Auto merge of #152450 - cuviper:stable-next, r=cuviper

[stable] prepare Rust 1.93.1

This includes the following backported fixes:

- Don't try to recover keyword as non-keyword identifier rust-lang/rust#150590
- Fix `panicking_unwrap` FP on field access with implicit deref rust-lang/rust-clippy#16196
- Revert "Update wasm-related dependencies in CI" rust-lang/rust#152259

And these are just to avoid recent CI issues:

- Remove rustdoc GUI flaky test rust-lang/rust#152116
- Remove the 4 failing tests from rustdoc-gui rust-lang/rust#152194

r? @rust-lang/release
@rustbot ping relnotes-interest-group

.github/FUNDING.yml

@@ -1 +0,0 @@
-custom: ["rust-lang.org/funding"]

.github/ISSUE_TEMPLATE/ice.md

@@ -2,7 +2,6 @@
 name: Internal Compiler Error
 about: Create a report for an internal compiler error in rustc.
 labels: C-bug, I-ICE, T-compiler
-title: "[ICE]: "
 ---
 <!--
 Thank you for finding an Internal Compiler Error! 🧊  If possible, try to provide

.github/workflows/ci.yml

@@ -11,9 +11,11 @@ name: CI
 on:
   push:
     branches:
-      - automation/bors/auto
+      - auto
-      - automation/bors/try
+      - try
       - try-perf
+      - automation/bors/try
+      - automation/bors/auto
   pull_request:
     branches:
       - "**"
@@ -31,10 +33,9 @@ defaults:
 
 concurrency:
   # For a given workflow, if we push to the same branch, cancel all previous builds on that branch.
-  # We add an exception for try builds (automation/bors/try branch) and unrolled rollup builds
+  # We add an exception for try builds (try branch) and unrolled rollup builds (try-perf), which
-  # (try-perf), which are all triggered on the same branch, but which should be able to run
+  # are all triggered on the same branch, but which should be able to run concurrently.
-  # concurrently.
+  group: ${{ github.workflow }}-${{ ((github.ref == 'refs/heads/try' || github.ref == 'refs/heads/try-perf' || github.ref == 'refs/heads/automation/bors/try') && github.sha) || github.ref }}
-  group: ${{ github.workflow }}-${{ ((github.ref == 'refs/heads/try-perf' || github.ref == 'refs/heads/automation/bors/try') && github.sha) || github.ref }}
   cancel-in-progress: true
 env:
   TOOLSTATE_REPO: "https://github.com/rust-lang-nursery/rust-toolstate"
@@ -56,7 +57,7 @@ jobs:
       - name: Test citool
         # Only test citool on the auto branch, to reduce latency of the calculate matrix job
         # on PR/try builds.
-        if: ${{ github.ref == 'refs/heads/automation/bors/auto' }}
+        if: ${{ github.ref == 'refs/heads/auto' || github.ref == 'refs/heads/automation/bors/auto' }}
         run: |
           cd src/ci/citool
           CARGO_INCREMENTAL=0 cargo test
@@ -79,7 +80,7 @@ jobs:
     # access the environment.
     #
     # We only enable the environment for the rust-lang/rust repository, so that CI works on forks.
-    environment: ${{ ((github.repository == 'rust-lang/rust' && (github.ref == 'refs/heads/try-perf' || github.ref == 'refs/heads/automation/bors/try' || github.ref == 'refs/heads/automation/bors/auto')) && 'bors') || '' }}
+    environment: ${{ ((github.repository == 'rust-lang/rust' && (github.ref == 'refs/heads/try' || github.ref == 'refs/heads/try-perf' || github.ref == 'refs/heads/automation/bors/try' || github.ref == 'refs/heads/auto' || github.ref == 'refs/heads/automation/bors/auto')) && 'bors') || '' }}
     env:
       CI_JOB_NAME: ${{ matrix.name }}
       CI_JOB_DOC_URL: ${{ matrix.doc_url }}
@@ -165,6 +166,9 @@ jobs:
       - name: install sccache
         run: src/ci/scripts/install-sccache.sh
 
+      - name: select Xcode
+        run: src/ci/scripts/select-xcode.sh
+
       - name: install clang
         run: src/ci/scripts/install-clang.sh
 
@@ -302,22 +306,30 @@ jobs:
           DD_GITHUB_JOB_NAME: ${{ matrix.full_name }}
         run: ./build/citool/debug/citool upload-build-metrics build/cpu-usage.csv
 
-  # This job is used to publish toolstate for successful auto builds.
+  # This job isused to tell bors the final status of the build, as there is no practical way to detect
+  # when a workflow is successful listening to webhooks only in our current bors implementation (homu).
   outcome:
-    name: publish toolstate
+    name: bors build finished
     runs-on: ubuntu-24.04
     needs: [ calculate_matrix, job ]
-    if: ${{ needs.calculate_matrix.outputs.run_type == 'auto' }}
+    # !cancelled() executes the job regardless of whether the previous jobs passed or failed
-    environment: ${{ (github.repository == 'rust-lang/rust' && 'bors') || '' }}
+    if: ${{ !cancelled() && contains(fromJSON('["auto", "try"]'), needs.calculate_matrix.outputs.run_type) }}
+    environment: ${{ ((github.repository == 'rust-lang/rust' && (github.ref == 'refs/heads/try' || github.ref == 'refs/heads/try-perf' || github.ref == 'refs/heads/automation/bors/try' || github.ref == 'refs/heads/auto' || github.ref == 'refs/heads/automation/bors/auto')) && 'bors') || '' }}
     steps:
       - name: checkout the source code
         uses: actions/checkout@v5
         with:
           fetch-depth: 2
+      # Calculate the exit status of the whole CI workflow.
+      # If all dependent jobs were successful, this exits with 0 (and the outcome job continues successfully).
+      # If a some dependent job has failed, this exits with 1.
+      - name: calculate the correct exit status
+        run: jq --exit-status 'all(.result == "success" or .result == "skipped")' <<< '${{ toJson(needs) }}'
       # Publish the toolstate if an auto build succeeds (just before push to the default branch)
       - name: publish toolstate
         run: src/ci/publish_toolstate.sh
         shell: bash
+        if: needs.calculate_matrix.outputs.run_type == 'auto'
         env:
           TOOLSTATE_ISSUES_API_URL: https://api.github.com/repos/rust-lang/rust/issues
           TOOLSTATE_PUBLISH: 1

.github/workflows/dependencies.yml

@@ -62,9 +62,19 @@ jobs:
           rustup toolchain install --no-self-update --profile minimal $TOOLCHAIN
           rustup default $TOOLCHAIN
 
-      - name: cargo update
+      - name: cargo update compiler & tools
-        run: ./src/tools/update-lockfile.sh
+        # Remove first line that always just says "Updating crates.io index"
-
+        run: |
+          echo -e "\ncompiler & tools dependencies:" >> cargo_update.log
+          cargo update 2>&1 | sed '/crates.io index/d' | tee -a cargo_update.log
+      - name: cargo update library
+        run: |
+          echo -e "\nlibrary dependencies:" >> cargo_update.log
+          cargo update --manifest-path library/Cargo.toml 2>&1 | sed '/crates.io index/d' | tee -a cargo_update.log
+      - name: cargo update rustbook
+        run: |
+          echo -e "\nrustbook dependencies:" >> cargo_update.log
+          cargo update --manifest-path src/tools/rustbook/Cargo.toml 2>&1 | sed '/crates.io index/d' | tee -a cargo_update.log
       - name: upload Cargo.lock artifact for use in PR
         uses: actions/upload-artifact@v4
         with:

.github/workflows/ghcr.yml

@@ -55,8 +55,6 @@ jobs:
           images=(
             # Mirrored because used by the tidy job, which doesn't cache Docker images
             "ubuntu:22.04"
-            # Mirrored because used by x86-64-gnu-miri
-            "ubuntu:24.04"
             # Mirrored because used by all linux CI jobs, including tidy
             "moby/buildkit:buildx-stable-1"
             # Mirrored because used when CI is running inside a Docker container

.gitmodules

@@ -25,7 +25,7 @@
 [submodule "src/llvm-project"]
 	path = src/llvm-project
 	url = https://github.com/rust-lang/llvm-project.git
-	branch = rustc/22.1-2026-01-27
+	branch = rustc/21.1-2025-08-01
 	shallow = true
 [submodule "src/doc/embedded-book"]
 	path = src/doc/embedded-book

.mailmap

@@ -83,7 +83,6 @@ Ben Sago <ogham@users.noreply.github.com> <ogham@bsago.me>
 Ben Striegel <ben.striegel@gmail.com>
 Benjamin Jackman <ben@jackman.biz>
 Benoît Cortier <benoit.cortier@fried-world.eu>
-binarycat <binarycat@envs.net> lolbinarycat <dogedoge61+github@gmail.com> <dogedoge61@gmail.com>
 Bheesham Persaud <bheesham123@hotmail.com> Bheesham Persaud <bheesham.persaud@live.ca>
 bjorn3 <17426603+bjorn3@users.noreply.github.com> <bjorn3@users.noreply.github.com>
 bjorn3 <17426603+bjorn3@users.noreply.github.com> <bjorn3_gh@protonmail.com>
@@ -96,7 +95,6 @@ boolean_coercion <booleancoercion@gmail.com>
 Boris Egorov <jightuse@gmail.com> <egorov@linux.com>
 bors <bors@rust-lang.org> bors[bot] <26634292+bors[bot]@users.noreply.github.com>
 bors <bors@rust-lang.org> bors[bot] <bors[bot]@users.noreply.github.com>
-bors <bors@rust-lang.org> <122020455+rust-bors[bot]@users.noreply.github.com>
 BoxyUwU <rust@boxyuwu.dev>
 BoxyUwU <rust@boxyuwu.dev> <supbscripter@gmail.com>
 Braden Nelson <moonheart08@users.noreply.github.com>
@@ -432,7 +430,6 @@ Lzu Tao <taolzu@gmail.com>
 Maik Klein <maikklein@googlemail.com>
 Maja Kądziołka <maya@compilercrim.es> <github@compilercrim.es>
 Maja Kądziołka <maya@compilercrim.es> <kuba@kadziolka.net>
-Makai <m4kai410@gmail.com>
 Malo Jaffré <jaffre.malo@gmail.com>
 Manish Goregaokar <manishsmail@gmail.com>
 Mara Bos <m-ou.se@m-ou.se>

CONTRIBUTING.md

@@ -10,7 +10,7 @@ the Zulip stream is the best place to *ask* for help.
 
 Documentation for contributing to the compiler or tooling is located in the [Guide to Rustc
 Development][rustc-dev-guide], commonly known as the [rustc-dev-guide]. Documentation for the
-standard library is in the [Standard library developers Guide][std-dev-guide], commonly known as the [std-dev-guide].
+standard library in the [Standard library developers Guide][std-dev-guide], commonly known as the [std-dev-guide].
 
 ## Making changes to subtrees and submodules
 

INSTALL.md

@@ -97,7 +97,7 @@ See [the rustc-dev-guide for more info][sysllvm].
       --set llvm.ninja=false \
       --set rust.debug-assertions=false \
       --set rust.jemalloc \
-      --set rust.bootstrap-override-lld=true \
+      --set rust.use-lld=true \
       --set rust.lto=thin \
       --set rust.codegen-units=1
    ```
@@ -233,7 +233,7 @@ itself back on after some time).
 
 ### MSVC
 
-MSVC builds of Rust additionally require an installation of:
+MSVC builds of Rust additionally requires an installation of:
 
 - Visual Studio 2022 (or later) build tools so `rustc` can use its linker. Older
   Visual Studio versions such as 2019 *may* work but aren't actively tested.

RELEASES.md

@@ -1555,7 +1555,7 @@ Compatibility Notes
 - [Check well-formedness of the source type's signature in fn pointer casts.](https://github.com/rust-lang/rust/pull/129021) This partly closes a soundness hole that comes when casting a function item to function pointer
 - [Use equality instead of subtyping when resolving type dependent paths.](https://github.com/rust-lang/rust/pull/129073)
 - Linking on macOS now correctly includes Rust's default deployment target. Due to a linker bug, you might have to pass `MACOSX_DEPLOYMENT_TARGET` or fix your `#[link]` attributes to point to the correct frameworks. See <https://github.com/rust-lang/rust/pull/129369>.
-- [Rust will now correctly raise an error for `repr(Rust)` written on non-`struct`/`enum`/`union` items, since it previously did not have any effect.](https://github.com/rust-lang/rust/pull/129422)
+- [Rust will now correctly raise an error for `repr(Rust)` written on non-`struct`/`enum`/`union` items, since it previous did not have any effect.](https://github.com/rust-lang/rust/pull/129422)
 - The future incompatibility lint `deprecated_cfg_attr_crate_type_name` [has been made into a hard error](https://github.com/rust-lang/rust/pull/129670). It was used to deny usage of `#![crate_type]` and `#![crate_name]` attributes in `#![cfg_attr]`, which required a hack in the compiler to be able to change the used crate type and crate name after cfg expansion.
   Users can use `--crate-type` instead of `#![cfg_attr(..., crate_type = "...")]` and `--crate-name` instead of `#![cfg_attr(..., crate_name = "...")]` when running `rustc`/`cargo rustc` on the command line.
   Use of those two attributes outside of `#![cfg_attr]` continue to be fully supported.
@@ -1731,7 +1731,7 @@ Cargo
 Compatibility Notes
 -------------------
  - We now [disallow setting some built-in cfgs via the command-line](https://github.com/rust-lang/rust/pull/126158) with the newly added [`explicit_builtin_cfgs_in_flags`](https://doc.rust-lang.org/rustc/lints/listing/deny-by-default.html#explicit-builtin-cfgs-in-flags) lint in order to prevent incoherent state, eg. `windows` cfg active but target is Linux based. The appropriate [`rustc` flag](https://doc.rust-lang.org/rustc/command-line-arguments.html) should be used instead.
-- The standard library has a new implementation of `binary_search` which significantly improves performance ([#128254](https://github.com/rust-lang/rust/pull/128254)). However when a sorted slice has multiple values which compare equal, the new implementation may select a different value among the equal ones than the old implementation.
+- The standard library has a new implementation of `binary_search` which is significantly improves performance ([#128254](https://github.com/rust-lang/rust/pull/128254)). However when a sorted slice has multiple values which compare equal, the new implementation may select a different value among the equal ones than the old implementation.
 - [illumos/Solaris now sets `MSG_NOSIGNAL` when writing to sockets](https://github.com/rust-lang/rust/pull/128259). This avoids killing the process with SIGPIPE when writing to a closed socket, which matches the existing behavior on other UNIX targets.
 - [Removes a problematic hack that always passed the --whole-archive linker flag for tests, which may cause linker errors for code accidentally relying on it.](https://github.com/rust-lang/rust/pull/128400)
 - The WebAssembly target features `multivalue` and `reference-types` are now
@@ -1881,7 +1881,7 @@ These changes do not affect any public interfaces of Rust, but they represent
 significant improvements to the performance or internals of rustc and related
 tools.
 
-- [Add a Rust-for-Linux `auto` CI job to check kernel builds.](https://github.com/rust-lang/rust/pull/125209/)
+- [Add a Rust-for Linux `auto` CI job to check kernel builds.](https://github.com/rust-lang/rust/pull/125209/)
 
 Version 1.80.1 (2024-08-08)
 ===========================
@@ -4519,7 +4519,7 @@ Compatibility Notes
   saturating to `0` instead][89926]. In the real world the panic happened mostly
   on platforms with buggy monotonic clock implementations rather than catching
   programming errors like reversing the start and end times. Such programming
-  errors will now result in `0` rather than a panic.
+  errors will now results in `0` rather than a panic.
 - In a future release we're planning to increase the baseline requirements for
   the Linux kernel to version 3.2, and for glibc to version 2.17. We'd love
   your feedback in [PR #95026][95026].

REUSE.toml

@@ -53,7 +53,7 @@ path = [
 ]
 precedence = "override"
 SPDX-FileCopyrightText = "The Rust Project Developers (see https://thanks.rust-lang.org)"
-SPDX-License-Identifier = "MIT OR Apache-2.0"
+SPDX-License-Identifier = "MIT or Apache-2.0"
 
 [[annotations]]
 path = "compiler/rustc_llvm/llvm-wrapper/SymbolWrapper.cpp"

bootstrap.example.toml

@@ -106,9 +106,6 @@
 # Whether to build LLVM with support for it's gpu offload runtime.
 #llvm.offload = false
 
-# Absolute path to the directory containing ClangConfig.cmake
-#llvm.offload-clang-dir = ""
-
 # When true, link libstdc++ statically into the rustc_llvm.
 # This is useful if you don't want to use the dynamic version of that
 # library provided by LLVM.
@@ -194,31 +191,6 @@
 # Currently, this is only supported for the `x86_64-unknown-linux-gnu` target.
 #gcc.download-ci-gcc = false
 
-# Provide a directory of prebuilt libgccjit.so dylibs for given (host, target) compilation pairs.
-# This is useful when you want to cross-compile `rustc` to another target since GCC is not a
-# multi-target compiler.
-# You have to use a directory structure that looks like this:
-# `<libgccjit-libs-dir>/<host>/<target>/libgccjit.so`.
-# For example:
-#
-# ```
-# <libgccjit-libs-dir>
-# ├── m68k-unknown-linux-gnu
-# │   └── m68k-unknown-linux-gnu
-# │       └── libgccjit.so
-# └── x86_64-unknown-linux-gnu
-#     ├── m68k-unknown-linux-gnu
-#     │   └── libgccjit.so
-#     └── x86_64-unknown-linux-gnu
-#         └── libgccjit.so
-# ```
-# The directory above would allow you to cross-compile rustc from x64 to m68k
-#
-# Note that this option has priority over `gcc.download-ci-gcc`.
-# If you set both, bootstrap will first try to load libgccjit.so from this directory.
-# Only if it isn't found, it will try to download it from CI or build it locally.
-#gcc.libgccjit-libs-dir = "/path/to/libgccjit-libs-dir"
-
 # =============================================================================
 # General build configuration options
 # =============================================================================

compiler/rustc/src/main.rs

@@ -3,8 +3,6 @@
 // Several crates are depended upon but unused so that they are present in the sysroot
 #![expect(unused_crate_dependencies)]
 
-use std::process::ExitCode;
-
 // A note about jemalloc: rustc uses jemalloc when built for CI and
 // distribution. The obvious way to do this is with the `#[global_allocator]`
 // mechanism. However, for complicated reasons (see
@@ -40,6 +38,6 @@ use std::process::ExitCode;
 #[cfg(feature = "jemalloc")]
 use tikv_jemalloc_sys as _;
 
-fn main() -> ExitCode {
+fn main() {
     rustc_driver::main()
 }

compiler/rustc_abi/src/callconv.rs

@@ -60,7 +60,6 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
     /// This is public so that it can be used in unit tests, but
     /// should generally only be relevant to the ABI details of
     /// specific targets.
-    #[tracing::instrument(skip(cx), level = "debug")]
     pub fn homogeneous_aggregate<C>(&self, cx: &C) -> Result<HomogeneousAggregate, Heterogeneous>
     where
         Ty: TyAbiInterface<'a, C> + Copy,
@@ -83,10 +82,6 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
                 }))
             }
 
-            BackendRepr::ScalableVector { .. } => {
-                unreachable!("`homogeneous_aggregate` should not be called for scalable vectors")
-            }
-
             BackendRepr::ScalarPair(..) | BackendRepr::Memory { sized: true } => {
                 // Helper for computing `homogeneous_aggregate`, allowing a custom
                 // starting offset (used below for handling variants).

compiler/rustc_abi/src/callconv/reg.rs

@@ -35,7 +35,6 @@ impl Reg {
 
     reg_ctor!(f32, Float, 32);
     reg_ctor!(f64, Float, 64);
-    reg_ctor!(f128, Float, 128);
 }
 
 impl Reg {

compiler/rustc_abi/src/canon_abi.rs

@@ -27,7 +27,6 @@ pub enum CanonAbi {
     C,
     Rust,
     RustCold,
-    RustPreserveNone,
 
     /// An ABI that rustc does not know how to call or define.
     Custom,
@@ -55,7 +54,7 @@ pub enum CanonAbi {
 impl CanonAbi {
     pub fn is_rustic_abi(self) -> bool {
         match self {
-            CanonAbi::Rust | CanonAbi::RustCold | CanonAbi::RustPreserveNone => true,
+            CanonAbi::Rust | CanonAbi::RustCold => true,
             CanonAbi::C
             | CanonAbi::Custom
             | CanonAbi::Arm(_)
@@ -75,7 +74,6 @@ impl fmt::Display for CanonAbi {
             CanonAbi::C => ExternAbi::C { unwind: false },
             CanonAbi::Rust => ExternAbi::Rust,
             CanonAbi::RustCold => ExternAbi::RustCold,
-            CanonAbi::RustPreserveNone => ExternAbi::RustPreserveNone,
             CanonAbi::Custom => ExternAbi::Custom,
             CanonAbi::Arm(arm_call) => match arm_call {
                 ArmCall::Aapcs => ExternAbi::Aapcs { unwind: false },

compiler/rustc_abi/src/extern_abi.rs

@@ -42,13 +42,6 @@ pub enum ExternAbi {
     /// in a platform-agnostic way.
     RustInvalid,
 
-    /// Preserves no registers.
-    ///
-    /// Note, that this ABI is not stable in the registers it uses, is intended as an optimization
-    /// and may fall-back to a more conservative calling convention if the backend does not support
-    /// forcing callers to save all registers.
-    RustPreserveNone,
-
     /// Unstable impl detail that directly uses Rust types to describe the ABI to LLVM.
     /// Even normally-compatible Rust types can become ABI-incompatible with this ABI!
     Unadjusted,
@@ -74,6 +67,7 @@ pub enum ExternAbi {
 
     /* gpu */
     /// An entry-point function called by the GPU's host
+    // FIXME: should not be callable from Rust on GPU targets, is for host's use only
     GpuKernel,
     /// An entry-point function called by the GPU's host
     // FIXME: why do we have two of these?
@@ -170,7 +164,6 @@ abi_impls! {
             RustCall =><= "rust-call",
             RustCold =><= "rust-cold",
             RustInvalid =><= "rust-invalid",
-            RustPreserveNone =><= "rust-preserve-none",
             Stdcall { unwind: false } =><= "stdcall",
             Stdcall { unwind: true } =><= "stdcall-unwind",
             System { unwind: false } =><= "system",
@@ -251,7 +244,7 @@ impl ExternAbi {
     /// - are subject to change between compiler versions
     pub fn is_rustic_abi(self) -> bool {
         use ExternAbi::*;
-        matches!(self, Rust | RustCall | RustCold | RustPreserveNone)
+        matches!(self, Rust | RustCall | RustCold)
     }
 
     /// Returns whether the ABI supports C variadics. This only controls whether we allow *imports*
@@ -323,8 +316,7 @@ impl ExternAbi {
             | Self::Thiscall { .. }
             | Self::Vectorcall { .. }
             | Self::SysV64 { .. }
-            | Self::Win64 { .. }
+            | Self::Win64 { .. } => true,
-            | Self::RustPreserveNone => true,
         }
     }
 }

compiler/rustc_abi/src/extern_abi/tests.rs

@@ -1,7 +1,6 @@
+use std::assert_matches::assert_matches;
 use std::str::FromStr;
 
-use rustc_data_structures::assert_matches;
-
 use super::*;
 
 #[allow(non_snake_case)]

compiler/rustc_abi/src/layout.rs

@@ -11,7 +11,7 @@ use tracing::{debug, trace};
 use crate::{
     AbiAlign, Align, BackendRepr, FieldsShape, HasDataLayout, IndexSlice, IndexVec, Integer,
     LayoutData, Niche, NonZeroUsize, Primitive, ReprOptions, Scalar, Size, StructKind, TagEncoding,
-    TargetDataLayout, Variants, WrappingRange,
+    Variants, WrappingRange,
 };
 
 mod coroutine;
@@ -143,32 +143,58 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
         })
     }
 
-    pub fn scalable_vector_type<FieldIdx, VariantIdx, F>(
+    pub fn simd_type<
-        &self,
-        element: F,
-        count: u64,
-    ) -> LayoutCalculatorResult<FieldIdx, VariantIdx, F>
-    where
         FieldIdx: Idx,
         VariantIdx: Idx,
         F: AsRef<LayoutData<FieldIdx, VariantIdx>> + fmt::Debug,
-    {
+    >(
-        vector_type_layout(VectorKind::Scalable, self.cx.data_layout(), element, count)
-    }
-
-    pub fn simd_type<FieldIdx, VariantIdx, F>(
         &self,
         element: F,
         count: u64,
         repr_packed: bool,
-    ) -> LayoutCalculatorResult<FieldIdx, VariantIdx, F>
+    ) -> LayoutCalculatorResult<FieldIdx, VariantIdx, F> {
-    where
+        let elt = element.as_ref();
-        FieldIdx: Idx,
+        if count == 0 {
-        VariantIdx: Idx,
+            return Err(LayoutCalculatorError::ZeroLengthSimdType);
-        F: AsRef<LayoutData<FieldIdx, VariantIdx>> + fmt::Debug,
+        } else if count > crate::MAX_SIMD_LANES {
-    {
+            return Err(LayoutCalculatorError::OversizedSimdType {
-        let kind = if repr_packed { VectorKind::PackedFixed } else { VectorKind::Fixed };
+                max_lanes: crate::MAX_SIMD_LANES,
-        vector_type_layout(kind, self.cx.data_layout(), element, count)
+            });
+        }
+
+        let BackendRepr::Scalar(e_repr) = elt.backend_repr else {
+            return Err(LayoutCalculatorError::NonPrimitiveSimdType(element));
+        };
+
+        // Compute the size and alignment of the vector
+        let dl = self.cx.data_layout();
+        let size =
+            elt.size.checked_mul(count, dl).ok_or_else(|| LayoutCalculatorError::SizeOverflow)?;
+        let (repr, align) = if repr_packed && !count.is_power_of_two() {
+            // Non-power-of-two vectors have padding up to the next power-of-two.
+            // If we're a packed repr, remove the padding while keeping the alignment as close
+            // to a vector as possible.
+            (BackendRepr::Memory { sized: true }, Align::max_aligned_factor(size))
+        } else {
+            (BackendRepr::SimdVector { element: e_repr, count }, dl.llvmlike_vector_align(size))
+        };
+        let size = size.align_to(align);
+
+        Ok(LayoutData {
+            variants: Variants::Single { index: VariantIdx::new(0) },
+            fields: FieldsShape::Arbitrary {
+                offsets: [Size::ZERO].into(),
+                memory_index: [0].into(),
+            },
+            backend_repr: repr,
+            largest_niche: elt.largest_niche,
+            uninhabited: false,
+            size,
+            align: AbiAlign::new(align),
+            max_repr_align: None,
+            unadjusted_abi_align: elt.align.abi,
+            randomization_seed: elt.randomization_seed.wrapping_add(Hash64::new(count)),
+        })
     }
 
     /// Compute the layout for a coroutine.
@@ -427,7 +453,6 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
                 BackendRepr::Scalar(..)
                 | BackendRepr::ScalarPair(..)
                 | BackendRepr::SimdVector { .. }
-                | BackendRepr::ScalableVector { .. }
                 | BackendRepr::Memory { .. } => repr,
             },
         };
@@ -499,8 +524,7 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
                     hide_niches(a);
                     hide_niches(b);
                 }
-                BackendRepr::SimdVector { element, .. }
+                BackendRepr::SimdVector { element, count: _ } => hide_niches(element),
-                | BackendRepr::ScalableVector { element, .. } => hide_niches(element),
                 BackendRepr::Memory { sized: _ } => {}
             }
             st.largest_niche = None;
@@ -714,7 +738,7 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
                 },
                 fields: FieldsShape::Arbitrary {
                     offsets: [niche_offset].into(),
-                    in_memory_order: [FieldIdx::new(0)].into(),
+                    memory_index: [0].into(),
                 },
                 backend_repr: abi,
                 largest_niche,
@@ -1008,8 +1032,8 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
                 let pair =
                     LayoutData::<FieldIdx, VariantIdx>::scalar_pair(&self.cx, tag, prim_scalar);
                 let pair_offsets = match pair.fields {
-                    FieldsShape::Arbitrary { ref offsets, ref in_memory_order } => {
+                    FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
-                        assert_eq!(in_memory_order.raw, [FieldIdx::new(0), FieldIdx::new(1)]);
+                        assert_eq!(memory_index.raw, [0, 1]);
                         offsets
                     }
                     _ => panic!("encountered a non-arbitrary layout during enum layout"),
@@ -1061,7 +1085,7 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
             },
             fields: FieldsShape::Arbitrary {
                 offsets: [Size::ZERO].into(),
-                in_memory_order: [FieldIdx::new(0)].into(),
+                memory_index: [0].into(),
             },
             largest_niche,
             uninhabited,
@@ -1110,10 +1134,10 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
         let pack = repr.pack;
         let mut align = if pack.is_some() { dl.i8_align } else { dl.aggregate_align };
         let mut max_repr_align = repr.align;
-        let mut in_memory_order: IndexVec<u32, FieldIdx> = fields.indices().collect();
+        let mut inverse_memory_index: IndexVec<u32, FieldIdx> = fields.indices().collect();
         let optimize_field_order = !repr.inhibit_struct_field_reordering();
         let end = if let StructKind::MaybeUnsized = kind { fields.len() - 1 } else { fields.len() };
-        let optimizing = &mut in_memory_order.raw[..end];
+        let optimizing = &mut inverse_memory_index.raw[..end];
         let fields_excluding_tail = &fields.raw[..end];
         // unsizable tail fields are excluded so that we use the same seed for the sized and unsized layouts.
         let field_seed = fields_excluding_tail
@@ -1248,10 +1272,12 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
                 //                 regardless of the status of `-Z randomize-layout`
             }
         }
-        // in_memory_order holds field indices by increasing memory offset.
+        // inverse_memory_index holds field indices by increasing memory offset.
-        // That is, if field 5 has offset 0, the first element of in_memory_order is 5.
+        // That is, if field 5 has offset 0, the first element of inverse_memory_index is 5.
         // We now write field offsets to the corresponding offset slot;
         // field 5 with offset 0 puts 0 in offsets[5].
+        // At the bottom of this function, we invert `inverse_memory_index` to
+        // produce `memory_index` (see `invert_mapping`).
         let mut unsized_field = None::<&F>;
         let mut offsets = IndexVec::from_elem(Size::ZERO, fields);
         let mut offset = Size::ZERO;
@@ -1263,7 +1289,7 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
             align = align.max(prefix_align);
             offset = prefix_size.align_to(prefix_align);
         }
-        for &i in &in_memory_order {
+        for &i in &inverse_memory_index {
             let field = &fields[i];
             if let Some(unsized_field) = unsized_field {
                 return Err(LayoutCalculatorError::UnexpectedUnsized(*unsized_field));
@@ -1320,6 +1346,18 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
 
         debug!("univariant min_size: {:?}", offset);
         let min_size = offset;
+        // As stated above, inverse_memory_index holds field indices by increasing offset.
+        // This makes it an already-sorted view of the offsets vec.
+        // To invert it, consider:
+        // If field 5 has offset 0, offsets[0] is 5, and memory_index[5] should be 0.
+        // Field 5 would be the first element, so memory_index is i:
+        // Note: if we didn't optimize, it's already right.
+        let memory_index = if optimize_field_order {
+            inverse_memory_index.invert_bijective_mapping()
+        } else {
+            debug_assert!(inverse_memory_index.iter().copied().eq(fields.indices()));
+            inverse_memory_index.into_iter().map(|it| it.index() as u32).collect()
+        };
         let size = min_size.align_to(align);
         // FIXME(oli-obk): deduplicate and harden these checks
         if size.bytes() >= dl.obj_size_bound() {
@@ -1375,11 +1413,8 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
                             let pair =
                                 LayoutData::<FieldIdx, VariantIdx>::scalar_pair(&self.cx, a, b);
                             let pair_offsets = match pair.fields {
-                                FieldsShape::Arbitrary { ref offsets, ref in_memory_order } => {
+                                FieldsShape::Arbitrary { ref offsets, ref memory_index } => {
-                                    assert_eq!(
+                                    assert_eq!(memory_index.raw, [0, 1]);
-                                        in_memory_order.raw,
-                                        [FieldIdx::new(0), FieldIdx::new(1)]
-                                    );
                                     offsets
                                 }
                                 FieldsShape::Primitive
@@ -1423,7 +1458,7 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
 
         Ok(LayoutData {
             variants: Variants::Single { index: VariantIdx::new(0) },
-            fields: FieldsShape::Arbitrary { offsets, in_memory_order },
+            fields: FieldsShape::Arbitrary { offsets, memory_index },
             backend_repr: abi,
             largest_niche,
             uninhabited,
@@ -1466,70 +1501,3 @@ impl<Cx: HasDataLayout> LayoutCalculator<Cx> {
         s
     }
 }
-
-enum VectorKind {
-    /// `#[rustc_scalable_vector]`
-    Scalable,
-    /// `#[repr(simd, packed)]`
-    PackedFixed,
-    /// `#[repr(simd)]`
-    Fixed,
-}
-
-fn vector_type_layout<FieldIdx, VariantIdx, F>(
-    kind: VectorKind,
-    dl: &TargetDataLayout,
-    element: F,
-    count: u64,
-) -> LayoutCalculatorResult<FieldIdx, VariantIdx, F>
-where
-    FieldIdx: Idx,
-    VariantIdx: Idx,
-    F: AsRef<LayoutData<FieldIdx, VariantIdx>> + fmt::Debug,
-{
-    let elt = element.as_ref();
-    if count == 0 {
-        return Err(LayoutCalculatorError::ZeroLengthSimdType);
-    } else if count > crate::MAX_SIMD_LANES {
-        return Err(LayoutCalculatorError::OversizedSimdType { max_lanes: crate::MAX_SIMD_LANES });
-    }
-
-    let BackendRepr::Scalar(element) = elt.backend_repr else {
-        return Err(LayoutCalculatorError::NonPrimitiveSimdType(element));
-    };
-
-    // Compute the size and alignment of the vector
-    let size =
-        elt.size.checked_mul(count, dl).ok_or_else(|| LayoutCalculatorError::SizeOverflow)?;
-    let (repr, align) = match kind {
-        VectorKind::Scalable => {
-            (BackendRepr::ScalableVector { element, count }, dl.llvmlike_vector_align(size))
-        }
-        // Non-power-of-two vectors have padding up to the next power-of-two.
-        // If we're a packed repr, remove the padding while keeping the alignment as close
-        // to a vector as possible.
-        VectorKind::PackedFixed if !count.is_power_of_two() => {
-            (BackendRepr::Memory { sized: true }, Align::max_aligned_factor(size))
-        }
-        VectorKind::PackedFixed | VectorKind::Fixed => {
-            (BackendRepr::SimdVector { element, count }, dl.llvmlike_vector_align(size))
-        }
-    };
-    let size = size.align_to(align);
-
-    Ok(LayoutData {
-        variants: Variants::Single { index: VariantIdx::new(0) },
-        fields: FieldsShape::Arbitrary {
-            offsets: [Size::ZERO].into(),
-            in_memory_order: [FieldIdx::new(0)].into(),
-        },
-        backend_repr: repr,
-        largest_niche: elt.largest_niche,
-        uninhabited: false,
-        size,
-        align: AbiAlign::new(align),
-        max_repr_align: None,
-        unadjusted_abi_align: elt.align.abi,
-        randomization_seed: elt.randomization_seed.wrapping_add(Hash64::new(count)),
-    })
-}

compiler/rustc_abi/src/layout/coroutine.rs

@@ -182,29 +182,33 @@ pub(super) fn layout<
     // CoroutineLayout.
     debug!("prefix = {:#?}", prefix);
     let (outer_fields, promoted_offsets, promoted_memory_index) = match prefix.fields {
-        FieldsShape::Arbitrary { mut offsets, in_memory_order } => {
+        FieldsShape::Arbitrary { mut offsets, memory_index } => {
+            let mut inverse_memory_index = memory_index.invert_bijective_mapping();
+
             // "a" (`0..b_start`) and "b" (`b_start..`) correspond to
             // "outer" and "promoted" fields respectively.
             let b_start = tag_index.plus(1);
             let offsets_b = IndexVec::from_raw(offsets.raw.split_off(b_start.index()));
             let offsets_a = offsets;
 
-            // Disentangle the "a" and "b" components of `in_memory_order`
+            // Disentangle the "a" and "b" components of `inverse_memory_index`
             // by preserving the order but keeping only one disjoint "half" each.
             // FIXME(eddyb) build a better abstraction for permutations, if possible.
-            let mut in_memory_order_a = IndexVec::<u32, FieldIdx>::new();
+            let inverse_memory_index_b: IndexVec<u32, FieldIdx> = inverse_memory_index
-            let mut in_memory_order_b = IndexVec::<u32, FieldIdx>::new();
+                .iter()
-            for i in in_memory_order {
+                .filter_map(|&i| i.index().checked_sub(b_start.index()).map(FieldIdx::new))
-                if let Some(j) = i.index().checked_sub(b_start.index()) {
+                .collect();
-                    in_memory_order_b.push(FieldIdx::new(j));
+            inverse_memory_index.raw.retain(|&i| i.index() < b_start.index());
-                } else {
+            let inverse_memory_index_a = inverse_memory_index;
-                    in_memory_order_a.push(i);
+
-                }
+            // Since `inverse_memory_index_{a,b}` each only refer to their
-            }
+            // respective fields, they can be safely inverted
+            let memory_index_a = inverse_memory_index_a.invert_bijective_mapping();
+            let memory_index_b = inverse_memory_index_b.invert_bijective_mapping();
 
             let outer_fields =
-                FieldsShape::Arbitrary { offsets: offsets_a, in_memory_order: in_memory_order_a };
+                FieldsShape::Arbitrary { offsets: offsets_a, memory_index: memory_index_a };
-            (outer_fields, offsets_b, in_memory_order_b.invert_bijective_mapping())
+            (outer_fields, offsets_b, memory_index_b)
         }
         _ => unreachable!(),
     };
@@ -232,7 +236,7 @@ pub(super) fn layout<
             )?;
             variant.variants = Variants::Single { index };
 
-            let FieldsShape::Arbitrary { offsets, in_memory_order } = variant.fields else {
+            let FieldsShape::Arbitrary { offsets, memory_index } = variant.fields else {
                 unreachable!();
             };
 
@@ -245,9 +249,8 @@ pub(super) fn layout<
             // promoted fields were being used, but leave the elements not in the
             // subset as `invalid_field_idx`, which we can filter out later to
             // obtain a valid (bijective) mapping.
-            let memory_index = in_memory_order.invert_bijective_mapping();
             let invalid_field_idx = promoted_memory_index.len() + memory_index.len();
-            let mut combined_in_memory_order =
+            let mut combined_inverse_memory_index =
                 IndexVec::from_elem_n(FieldIdx::new(invalid_field_idx), invalid_field_idx);
 
             let mut offsets_and_memory_index = iter::zip(offsets, memory_index);
@@ -265,18 +268,19 @@ pub(super) fn layout<
                             (promoted_offsets[field_idx], promoted_memory_index[field_idx])
                         }
                     };
-                    combined_in_memory_order[memory_index] = i;
+                    combined_inverse_memory_index[memory_index] = i;
                     offset
                 })
                 .collect();
 
-            // Remove the unused slots to obtain the combined `in_memory_order`
+            // Remove the unused slots and invert the mapping to obtain the
-            // (also see previous comment).
+            // combined `memory_index` (also see previous comment).
-            combined_in_memory_order.raw.retain(|&i| i.index() != invalid_field_idx);
+            combined_inverse_memory_index.raw.retain(|&i| i.index() != invalid_field_idx);
+            let combined_memory_index = combined_inverse_memory_index.invert_bijective_mapping();
 
             variant.fields = FieldsShape::Arbitrary {
                 offsets: combined_offsets,
-                in_memory_order: combined_in_memory_order,
+                memory_index: combined_memory_index,
             };
 
             size = size.max(variant.size);

compiler/rustc_abi/src/layout/simple.rs

@@ -16,7 +16,7 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
             variants: Variants::Single { index: VariantIdx::new(0) },
             fields: FieldsShape::Arbitrary {
                 offsets: IndexVec::new(),
-                in_memory_order: IndexVec::new(),
+                memory_index: IndexVec::new(),
             },
             backend_repr: BackendRepr::Memory { sized },
             largest_niche: None,
@@ -108,7 +108,7 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
             variants: Variants::Single { index: VariantIdx::new(0) },
             fields: FieldsShape::Arbitrary {
                 offsets: [Size::ZERO, b_offset].into(),
-                in_memory_order: [FieldIdx::new(0), FieldIdx::new(1)].into(),
+                memory_index: [0, 1].into(),
             },
             backend_repr: BackendRepr::ScalarPair(a, b),
             largest_niche,
@@ -133,7 +133,7 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
                 Some(fields) => FieldsShape::Union(fields),
                 None => FieldsShape::Arbitrary {
                     offsets: IndexVec::new(),
-                    in_memory_order: IndexVec::new(),
+                    memory_index: IndexVec::new(),
                 },
             },
             backend_repr: BackendRepr::Memory { sized: true },

compiler/rustc_abi/src/layout/ty.rs

@@ -155,7 +155,7 @@ impl<'a, Ty> AsRef<LayoutData<FieldIdx, VariantIdx>> for TyAndLayout<'a, Ty> {
 
 /// Trait that needs to be implemented by the higher-level type representation
 /// (e.g. `rustc_middle::ty::Ty`), to provide `rustc_target::abi` functionality.
-pub trait TyAbiInterface<'a, C>: Sized + std::fmt::Debug + std::fmt::Display {
+pub trait TyAbiInterface<'a, C>: Sized + std::fmt::Debug {
     fn ty_and_layout_for_variant(
         this: TyAndLayout<'a, Self>,
         cx: &C,
@@ -172,7 +172,6 @@ pub trait TyAbiInterface<'a, C>: Sized + std::fmt::Debug + std::fmt::Display {
     fn is_tuple(this: TyAndLayout<'a, Self>) -> bool;
     fn is_unit(this: TyAndLayout<'a, Self>) -> bool;
     fn is_transparent(this: TyAndLayout<'a, Self>) -> bool;
-    fn is_scalable_vector(this: TyAndLayout<'a, Self>) -> bool;
     /// See [`TyAndLayout::pass_indirectly_in_non_rustic_abis`] for details.
     fn is_pass_indirectly_in_non_rustic_abis_flag_set(this: TyAndLayout<'a, Self>) -> bool;
 }
@@ -272,13 +271,6 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
         Ty::is_transparent(self)
     }
 
-    pub fn is_scalable_vector<C>(self) -> bool
-    where
-        Ty: TyAbiInterface<'a, C>,
-    {
-        Ty::is_scalable_vector(self)
-    }
-
     /// If this method returns `true`, then this type should always have a `PassMode` of
     /// `Indirect { on_stack: false, .. }` when being used as the argument type of a function with a
     /// non-Rustic ABI (this is true for structs annotated with the
@@ -290,19 +282,7 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
     /// function call isn't allowed (a.k.a. `va_list`).
     ///
     /// This function handles transparent types automatically.
-    pub fn pass_indirectly_in_non_rustic_abis<C>(self, cx: &C) -> bool
+    pub fn pass_indirectly_in_non_rustic_abis<C>(mut self, cx: &C) -> bool
-    where
-        Ty: TyAbiInterface<'a, C> + Copy,
-    {
-        let base = self.peel_transparent_wrappers(cx);
-        Ty::is_pass_indirectly_in_non_rustic_abis_flag_set(base)
-    }
-
-    /// Recursively peel away transparent wrappers, returning the inner value.
-    ///
-    /// The return value is not `repr(transparent)` and/or does
-    /// not have a non-1zst field.
-    pub fn peel_transparent_wrappers<C>(mut self, cx: &C) -> Self
     where
         Ty: TyAbiInterface<'a, C> + Copy,
     {
@@ -312,7 +292,7 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
             self = field;
         }
 
-        self
+        Ty::is_pass_indirectly_in_non_rustic_abis_flag_set(self)
     }
 
     /// Finds the one field that is not a 1-ZST.

compiler/rustc_abi/src/lib.rs

@@ -1,6 +1,6 @@
 // tidy-alphabetical-start
-#![cfg_attr(all(feature = "nightly", bootstrap, test), feature(assert_matches))]
 #![cfg_attr(feature = "nightly", allow(internal_features))]
+#![cfg_attr(feature = "nightly", feature(assert_matches))]
 #![cfg_attr(feature = "nightly", feature(rustc_attrs))]
 #![cfg_attr(feature = "nightly", feature(step_trait))]
 // tidy-alphabetical-end
@@ -96,11 +96,9 @@ bitflags! {
         /// If true, the type is always passed indirectly by non-Rustic ABIs.
         /// See [`TyAndLayout::pass_indirectly_in_non_rustic_abis`] for details.
         const PASS_INDIRECTLY_IN_NON_RUSTIC_ABIS = 1 << 5;
-        const IS_SCALABLE        = 1 << 6;
+        /// Any of these flags being set prevent field reordering optimisation.
-         // Any of these flags being set prevent field reordering optimisation.
+        const FIELD_ORDER_UNOPTIMIZABLE   = ReprFlags::IS_C.bits()
-        const FIELD_ORDER_UNOPTIMIZABLE = ReprFlags::IS_C.bits()
                                  | ReprFlags::IS_SIMD.bits()
-                                 | ReprFlags::IS_SCALABLE.bits()
                                  | ReprFlags::IS_LINEAR.bits();
         const ABI_UNOPTIMIZABLE = ReprFlags::IS_C.bits() | ReprFlags::IS_SIMD.bits();
     }
@@ -137,19 +135,6 @@ impl IntegerType {
     }
 }
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
-#[cfg_attr(
-    feature = "nightly",
-    derive(Encodable_NoContext, Decodable_NoContext, HashStable_Generic)
-)]
-pub enum ScalableElt {
-    /// `N` in `rustc_scalable_vector(N)` - the element count of the scalable vector
-    ElementCount(u16),
-    /// `rustc_scalable_vector` w/out `N`, used for tuple types of scalable vectors that only
-    /// contain other scalable vectors
-    Container,
-}
-
 /// Represents the repr options provided by the user.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Default)]
 #[cfg_attr(
@@ -161,8 +146,6 @@ pub struct ReprOptions {
     pub align: Option<Align>,
     pub pack: Option<Align>,
     pub flags: ReprFlags,
-    /// `#[rustc_scalable_vector]`
-    pub scalable: Option<ScalableElt>,
     /// The seed to be used for randomizing a type's layout
     ///
     /// Note: This could technically be a `u128` which would
@@ -179,11 +162,6 @@ impl ReprOptions {
         self.flags.contains(ReprFlags::IS_SIMD)
     }
 
-    #[inline]
-    pub fn scalable(&self) -> bool {
-        self.flags.contains(ReprFlags::IS_SCALABLE)
-    }
-
     #[inline]
     pub fn c(&self) -> bool {
         self.flags.contains(ReprFlags::IS_C)
@@ -1636,14 +1614,19 @@ pub enum FieldsShape<FieldIdx: Idx> {
         // FIXME(eddyb) use small vector optimization for the common case.
         offsets: IndexVec<FieldIdx, Size>,
 
-        /// Maps memory order field indices to source order indices,
+        /// Maps source order field indices to memory order indices,
         /// depending on how the fields were reordered (if at all).
         /// This is a permutation, with both the source order and the
         /// memory order using the same (0..n) index ranges.
         ///
+        /// Note that during computation of `memory_index`, sometimes
+        /// it is easier to operate on the inverse mapping (that is,
+        /// from memory order to source order), and that is usually
+        /// named `inverse_memory_index`.
+        ///
         // FIXME(eddyb) build a better abstraction for permutations, if possible.
         // FIXME(camlorn) also consider small vector optimization here.
-        in_memory_order: IndexVec<u32, FieldIdx>,
+        memory_index: IndexVec<FieldIdx, u32>,
     },
 }
 
@@ -1677,17 +1660,51 @@ impl<FieldIdx: Idx> FieldsShape<FieldIdx> {
         }
     }
 
+    #[inline]
+    pub fn memory_index(&self, i: usize) -> usize {
+        match *self {
+            FieldsShape::Primitive => {
+                unreachable!("FieldsShape::memory_index: `Primitive`s have no fields")
+            }
+            FieldsShape::Union(_) | FieldsShape::Array { .. } => i,
+            FieldsShape::Arbitrary { ref memory_index, .. } => {
+                memory_index[FieldIdx::new(i)].try_into().unwrap()
+            }
+        }
+    }
+
     /// Gets source indices of the fields by increasing offsets.
     #[inline]
     pub fn index_by_increasing_offset(&self) -> impl ExactSizeIterator<Item = usize> {
+        let mut inverse_small = [0u8; 64];
+        let mut inverse_big = IndexVec::new();
+        let use_small = self.count() <= inverse_small.len();
+
+        // We have to write this logic twice in order to keep the array small.
+        if let FieldsShape::Arbitrary { ref memory_index, .. } = *self {
+            if use_small {
+                for (field_idx, &mem_idx) in memory_index.iter_enumerated() {
+                    inverse_small[mem_idx as usize] = field_idx.index() as u8;
+                }
+            } else {
+                inverse_big = memory_index.invert_bijective_mapping();
+            }
+        }
+
         // Primitives don't really have fields in the way that structs do,
         // but having this return an empty iterator for them is unhelpful
         // since that makes them look kinda like ZSTs, which they're not.
         let pseudofield_count = if let FieldsShape::Primitive = self { 1 } else { self.count() };
 
-        (0..pseudofield_count).map(move |i| match self {
+        (0..pseudofield_count).map(move |i| match *self {
             FieldsShape::Primitive | FieldsShape::Union(_) | FieldsShape::Array { .. } => i,
-            FieldsShape::Arbitrary { in_memory_order, .. } => in_memory_order[i as u32].index(),
+            FieldsShape::Arbitrary { .. } => {
+                if use_small {
+                    inverse_small[i] as usize
+                } else {
+                    inverse_big[i as u32].index()
+                }
+            }
         })
     }
 }
@@ -1719,10 +1736,6 @@ impl AddressSpace {
 pub enum BackendRepr {
     Scalar(Scalar),
     ScalarPair(Scalar, Scalar),
-    ScalableVector {
-        element: Scalar,
-        count: u64,
-    },
     SimdVector {
         element: Scalar,
         count: u64,
@@ -1741,12 +1754,6 @@ impl BackendRepr {
         match *self {
             BackendRepr::Scalar(_)
             | BackendRepr::ScalarPair(..)
-            // FIXME(rustc_scalable_vector): Scalable vectors are `Sized` while the
-            // `sized_hierarchy` feature is not yet fully implemented. After `sized_hierarchy` is
-            // fully implemented, scalable vectors will remain `Sized`, they just won't be
-            // `const Sized` - whether `is_unsized` continues to return `false` at that point will
-            // need to be revisited and will depend on what `is_unsized` is used for.
-            | BackendRepr::ScalableVector { .. }
             | BackendRepr::SimdVector { .. } => false,
             BackendRepr::Memory { sized } => !sized,
         }
@@ -1787,9 +1794,7 @@ impl BackendRepr {
             BackendRepr::Scalar(s) => Some(s.align(cx).abi),
             BackendRepr::ScalarPair(s1, s2) => Some(s1.align(cx).max(s2.align(cx)).abi),
             // The align of a Vector can vary in surprising ways
-            BackendRepr::SimdVector { .. }
+            BackendRepr::SimdVector { .. } | BackendRepr::Memory { .. } => None,
-            | BackendRepr::Memory { .. }
-            | BackendRepr::ScalableVector { .. } => None,
         }
     }
 
@@ -1811,9 +1816,7 @@ impl BackendRepr {
                 Some(size)
             }
             // The size of a Vector can vary in surprising ways
-            BackendRepr::SimdVector { .. }
+            BackendRepr::SimdVector { .. } | BackendRepr::Memory { .. } => None,
-            | BackendRepr::Memory { .. }
-            | BackendRepr::ScalableVector { .. } => None,
         }
     }
 
@@ -1828,9 +1831,6 @@ impl BackendRepr {
                 BackendRepr::SimdVector { element: element.to_union(), count }
             }
             BackendRepr::Memory { .. } => BackendRepr::Memory { sized: true },
-            BackendRepr::ScalableVector { element, count } => {
-                BackendRepr::ScalableVector { element: element.to_union(), count }
-            }
         }
     }
 
@@ -2071,9 +2071,7 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
     /// Returns `true` if this is an aggregate type (including a ScalarPair!)
     pub fn is_aggregate(&self) -> bool {
         match self.backend_repr {
-            BackendRepr::Scalar(_)
+            BackendRepr::Scalar(_) | BackendRepr::SimdVector { .. } => false,
-            | BackendRepr::SimdVector { .. }
-            | BackendRepr::ScalableVector { .. } => false,
             BackendRepr::ScalarPair(..) | BackendRepr::Memory { .. } => true,
         }
     }
@@ -2167,19 +2165,6 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
         self.is_sized() && self.size.bytes() == 0 && self.align.bytes() == 1
     }
 
-    /// Returns `true` if the size of the type is only known at runtime.
-    pub fn is_runtime_sized(&self) -> bool {
-        matches!(self.backend_repr, BackendRepr::ScalableVector { .. })
-    }
-
-    /// Returns the elements count of a scalable vector.
-    pub fn scalable_vector_element_count(&self) -> Option<u64> {
-        match self.backend_repr {
-            BackendRepr::ScalableVector { count, .. } => Some(count),
-            _ => None,
-        }
-    }
-
     /// Returns `true` if the type is a ZST and not unsized.
     ///
     /// Note that this does *not* imply that the type is irrelevant for layout! It can still have
@@ -2188,7 +2173,6 @@ impl<FieldIdx: Idx, VariantIdx: Idx> LayoutData<FieldIdx, VariantIdx> {
         match self.backend_repr {
             BackendRepr::Scalar(_)
             | BackendRepr::ScalarPair(..)
-            | BackendRepr::ScalableVector { .. }
             | BackendRepr::SimdVector { .. } => false,
             BackendRepr::Memory { sized } => sized && self.size.bytes() == 0,
         }

compiler/rustc_arena/src/lib.rs

@@ -10,9 +10,11 @@
 // tidy-alphabetical-start
 #![allow(clippy::mut_from_ref)] // Arena allocators are one place where this pattern is fine.
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(maybe_uninit_slice))]
 #![cfg_attr(test, feature(test))]
 #![deny(unsafe_op_in_unsafe_fn)]
 #![doc(test(no_crate_inject, attr(deny(warnings), allow(internal_features))))]
+#![feature(core_intrinsics)]
 #![feature(decl_macro)]
 #![feature(dropck_eyepatch)]
 #![feature(never_type)]
@@ -25,7 +27,7 @@ use std::cell::{Cell, RefCell};
 use std::marker::PhantomData;
 use std::mem::{self, MaybeUninit};
 use std::ptr::{self, NonNull};
-use std::{cmp, hint, slice};
+use std::{cmp, intrinsics, slice};
 
 use smallvec::SmallVec;
 
@@ -171,22 +173,8 @@ impl<T> TypedArena<T> {
         available_bytes >= additional_bytes
     }
 
-    /// Allocates storage for `len >= 1` values in this arena, and returns a
-    /// raw pointer to the first value's storage.
-    ///
-    /// # Safety
-    ///
-    /// Caller must initialize each of the `len` slots to a droppable value
-    /// before the arena is dropped.
-    ///
-    /// In practice, this typically means that the caller must be able to
-    /// raw-copy `len` already-initialized values into the slice without any
-    /// possibility of panicking.
-    ///
-    /// FIXME(Zalathar): This is *very* fragile; perhaps we need a different
-    /// approach to arena-allocating slices of droppable values.
     #[inline]
-    unsafe fn alloc_raw_slice(&self, len: usize) -> *mut T {
+    fn alloc_raw_slice(&self, len: usize) -> *mut T {
         assert!(size_of::<T>() != 0);
         assert!(len != 0);
 
@@ -221,7 +209,7 @@ impl<T> TypedArena<T> {
         &self,
         iter: impl IntoIterator<Item = Result<T, E>>,
     ) -> Result<&mut [T], E> {
-        // Despite the similarity with `DroplessArena`, we cannot reuse their fast case. The reason
+        // Despite the similarlty with `DroplessArena`, we cannot reuse their fast case. The reason
         // is subtle: these arenas are reentrant. In other words, `iter` may very well be holding a
         // reference to `self` and adding elements to the arena during iteration.
         //
@@ -242,15 +230,9 @@ impl<T> TypedArena<T> {
         }
         // Move the content to the arena by copying and then forgetting it.
         let len = vec.len();
-
+        let start_ptr = self.alloc_raw_slice(len);
-        // SAFETY: After allocating raw storage for exactly `len` values, we
-        // must fully initialize the storage without panicking, and we must
-        // also prevent the stale values in the vec from being dropped.
         Ok(unsafe {
-            let start_ptr = self.alloc_raw_slice(len);
-            // Initialize the newly-allocated storage without panicking.
             vec.as_ptr().copy_to_nonoverlapping(start_ptr, len);
-            // Prevent the stale values in the vec from being dropped.
             vec.set_len(0);
             slice::from_raw_parts_mut(start_ptr, len)
         })
@@ -451,7 +433,7 @@ impl DroplessArena {
             let bytes = align_up(layout.size(), DROPLESS_ALIGNMENT);
 
             // Tell LLVM that `end` is aligned to DROPLESS_ALIGNMENT.
-            unsafe { hint::assert_unchecked(end == align_down(end, DROPLESS_ALIGNMENT)) };
+            unsafe { intrinsics::assume(end == align_down(end, DROPLESS_ALIGNMENT)) };
 
             if let Some(sub) = end.checked_sub(bytes) {
                 let new_end = align_down(sub, layout.align());
@@ -509,6 +491,19 @@ impl DroplessArena {
         }
     }
 
+    /// Used by `Lift` to check whether this slice is allocated
+    /// in this arena.
+    #[inline]
+    pub fn contains_slice<T>(&self, slice: &[T]) -> bool {
+        for chunk in self.chunks.borrow_mut().iter_mut() {
+            let ptr = slice.as_ptr().cast::<u8>().cast_mut();
+            if chunk.start() <= ptr && chunk.end() >= ptr {
+                return true;
+            }
+        }
+        false
+    }
+
     /// Allocates a string slice that is copied into the `DroplessArena`, returning a
     /// reference to it. Will panic if passed an empty string.
     ///
@@ -590,7 +585,7 @@ impl DroplessArena {
         &self,
         iter: impl IntoIterator<Item = Result<T, E>>,
     ) -> Result<&mut [T], E> {
-        // Despite the similarity with `alloc_from_iter`, we cannot reuse their fast case, as we
+        // Despite the similarlty with `alloc_from_iter`, we cannot reuse their fast case, as we
         // cannot know the minimum length of the iterator in this case.
         assert!(size_of::<T>() != 0);
 
@@ -624,7 +619,7 @@ impl DroplessArena {
 /// - Types that are `!Copy` and `Drop`: these must be specified in the
 ///   arguments. The `TypedArena` will be used for them.
 ///
-#[rustc_macro_transparency = "semiopaque"]
+#[rustc_macro_transparency = "semitransparent"]
 pub macro declare_arena([$($a:tt $name:ident: $ty:ty,)*]) {
     #[derive(Default)]
     pub struct Arena<'tcx> {

compiler/rustc_ast/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2024"
 # tidy-alphabetical-start
 bitflags = "2.4.1"
 memchr = "2.7.6"
-rustc-literal-escaper = "0.0.7"
+rustc-literal-escaper = "0.0.5"
 rustc_ast_ir = { path = "../rustc_ast_ir" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_index = { path = "../rustc_index" }

compiler/rustc_ast/src/ast.rs

@@ -34,7 +34,6 @@ use rustc_span::source_map::{Spanned, respan};
 use rustc_span::{ByteSymbol, DUMMY_SP, ErrorGuaranteed, Ident, Span, Symbol, kw, sym};
 use thin_vec::{ThinVec, thin_vec};
 
-use crate::attr::data_structures::CfgEntry;
 pub use crate::format::*;
 use crate::token::{self, CommentKind, Delimiter};
 use crate::tokenstream::{DelimSpan, LazyAttrTokenStream, TokenStream};
@@ -142,11 +141,16 @@ impl Path {
     /// Check if this path is potentially a trivial const arg, i.e., one that can _potentially_
     /// be represented without an anon const in the HIR.
     ///
-    /// Returns true iff the path has exactly one segment, and it has no generic args
+    /// If `allow_mgca_arg` is true (as should be the case in most situations when
+    /// `#![feature(min_generic_const_args)]` is enabled), then this always returns true
+    /// because all paths are valid.
+    ///
+    /// Otherwise, it returns true iff the path has exactly one segment, and it has no generic args
     /// (i.e., it is _potentially_ a const parameter).
     #[tracing::instrument(level = "debug", ret)]
-    pub fn is_potential_trivial_const_arg(&self) -> bool {
+    pub fn is_potential_trivial_const_arg(&self, allow_mgca_arg: bool) -> bool {
-        self.segments.len() == 1 && self.segments.iter().all(|seg| seg.args.is_none())
+        allow_mgca_arg
+            || self.segments.len() == 1 && self.segments.iter().all(|seg| seg.args.is_none())
     }
 }
 
@@ -656,7 +660,11 @@ impl Pat {
             // A tuple pattern `(P0, .., Pn)` can be reparsed as `(T0, .., Tn)`
             // assuming `T0` to `Tn` are all syntactically valid as types.
             PatKind::Tuple(pats) => {
-                let tys = pats.iter().map(|pat| pat.to_ty()).collect::<Option<ThinVec<_>>>()?;
+                let mut tys = ThinVec::with_capacity(pats.len());
+                // FIXME(#48994) - could just be collected into an Option<Vec>
+                for pat in pats {
+                    tys.push(pat.to_ty()?);
+                }
                 TyKind::Tup(tys)
             }
             _ => return None,
@@ -1251,19 +1259,6 @@ pub enum StmtKind {
     MacCall(Box<MacCallStmt>),
 }
 
-impl StmtKind {
-    pub fn descr(&self) -> &'static str {
-        match self {
-            StmtKind::Let(_) => "local",
-            StmtKind::Item(_) => "item",
-            StmtKind::Expr(_) => "expression",
-            StmtKind::Semi(_) => "statement",
-            StmtKind::Empty => "semicolon",
-            StmtKind::MacCall(_) => "macro call",
-        }
-    }
-}
-
 #[derive(Clone, Encodable, Decodable, Debug, Walkable)]
 pub struct MacCallStmt {
     pub mac: Box<MacCall>,
@@ -1377,15 +1372,6 @@ pub enum UnsafeSource {
     UserProvided,
 }
 
-/// Track whether under `feature(min_generic_const_args)` this anon const
-/// was explicitly disambiguated as an anon const or not through the use of
-/// `const { ... }` syntax.
-#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, Walkable)]
-pub enum MgcaDisambiguation {
-    AnonConst,
-    Direct,
-}
-
 /// A constant (expression) that's not an item or associated item,
 /// but needs its own `DefId` for type-checking, const-eval, etc.
 /// These are usually found nested inside types (e.g., array lengths)
@@ -1395,7 +1381,6 @@ pub enum MgcaDisambiguation {
 pub struct AnonConst {
     pub id: NodeId,
     pub value: Box<Expr>,
-    pub mgca_disambiguation: MgcaDisambiguation,
 }
 
 /// An expression.
@@ -1414,20 +1399,26 @@ impl Expr {
     ///
     /// This will unwrap at most one block level (curly braces). After that, if the expression
     /// is a path, it mostly dispatches to [`Path::is_potential_trivial_const_arg`].
+    /// See there for more info about `allow_mgca_arg`.
     ///
-    /// This function will only allow paths with no qself, before dispatching to the `Path`
+    /// The only additional thing to note is that when `allow_mgca_arg` is false, this function
-    /// function of the same name.
+    /// will only allow paths with no qself, before dispatching to the `Path` function of
+    /// the same name.
     ///
     /// Does not ensure that the path resolves to a const param/item, the caller should check this.
     /// This also does not consider macros, so it's only correct after macro-expansion.
-    pub fn is_potential_trivial_const_arg(&self) -> bool {
+    pub fn is_potential_trivial_const_arg(&self, allow_mgca_arg: bool) -> bool {
         let this = self.maybe_unwrap_block();
-        if let ExprKind::Path(None, path) = &this.kind
+        if allow_mgca_arg {
-            && path.is_potential_trivial_const_arg()
+            matches!(this.kind, ExprKind::Path(..))
-        {
-            true
         } else {
-            false
+            if let ExprKind::Path(None, path) = &this.kind
+                && path.is_potential_trivial_const_arg(allow_mgca_arg)
+            {
+                true
+            } else {
+                false
+            }
         }
     }
 
@@ -1530,10 +1521,11 @@ impl Expr {
             // then type of result is trait object.
             // Otherwise we don't assume the result type.
             ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
-                let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) else {
+                if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
+                    TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
+                } else {
                     return None;
-                };
+                }
-                TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
             }
 
             ExprKind::Underscore => TyKind::Infer,
@@ -1807,21 +1799,15 @@ pub enum ExprKind {
     /// or a `gen` block (`gen move { ... }`).
     ///
     /// The span is the "decl", which is the header before the body `{ }`
-    /// including the `async`/`gen` keywords and possibly `move`.
+    /// including the `asyng`/`gen` keywords and possibly `move`.
     Gen(CaptureBy, Box<Block>, GenBlockKind, Span),
     /// An await expression (`my_future.await`). Span is of await keyword.
     Await(Box<Expr>, Span),
     /// A use expression (`x.use`). Span is of use keyword.
     Use(Box<Expr>, Span),
 
-    /// A try block (`try { ... }`), if the type is `None`, or
+    /// A try block (`try { ... }`).
-    /// A try block (`try bikeshed Ty { ... }`) if the type is `Some`.
+    TryBlock(Box<Block>),
-    ///
-    /// Note that `try bikeshed` is a *deliberately ridiculous* placeholder
-    /// syntax to avoid deciding what keyword or symbol should go there.
-    /// It's that way for experimentation only; an RFC to decide the final
-    /// semantics and syntax would be needed to put it on stabilization-track.
-    TryBlock(Box<Block>, Option<Box<Ty>>),
 
     /// An assignment (`a = foo()`).
     /// The `Span` argument is the span of the `=` token.
@@ -2104,20 +2090,6 @@ pub struct MacroDef {
     pub body: Box<DelimArgs>,
     /// `true` if macro was defined with `macro_rules`.
     pub macro_rules: bool,
-
-    /// Corresponds to `#[eii_declaration(...)]`.
-    /// `#[eii_declaration(...)]` is a built-in attribute macro, not a built-in attribute,
-    /// because we require some name resolution to occur in the parameters of this attribute.
-    /// Name resolution isn't possible in attributes otherwise, so we encode it in the AST.
-    /// During ast lowering, we turn it back into an attribute again
-    pub eii_declaration: Option<EiiDecl>,
-}
-
-#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
-pub struct EiiDecl {
-    /// path to the extern item we're targeting
-    pub foreign_item: Path,
-    pub impl_unsafe: bool,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug, Copy, Hash, Eq, PartialEq)]
@@ -2392,7 +2364,7 @@ impl FnSig {
 /// * the `G<Ty> = Ty` in `Trait<G<Ty> = Ty>`
 /// * the `A: Bound` in `Trait<A: Bound>`
 /// * the `RetTy` in `Trait(ArgTy, ArgTy) -> RetTy`
-/// * the `C = { Ct }` in `Trait<C = { Ct }>` (feature `min_generic_const_args`)
+/// * the `C = { Ct }` in `Trait<C = { Ct }>` (feature `associated_const_equality`)
 /// * the `f(..): Bound` in `Trait<f(..): Bound>` (feature `return_type_notation`)
 #[derive(Clone, Encodable, Decodable, Debug, Walkable)]
 pub struct AssocItemConstraint {
@@ -3131,16 +3103,8 @@ pub enum Const {
 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic, Walkable)]
 pub enum Defaultness {
-    /// Item is unmarked. Implicitly determined based off of position.
-    /// For impls, this is `final`; for traits, this is `default`.
-    ///
-    /// If you're expanding an item in a built-in macro or parsing an item
-    /// by hand, you probably want to use this.
-    Implicit,
-    /// `default`
     Default(Span),
-    /// `final`; per RFC 3678, only trait items may be *explicitly* marked final.
+    Final,
-    Final(Span),
 }
 
 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic, Walkable)]
@@ -3352,8 +3316,7 @@ impl UseTree {
 /// Distinguishes between `Attribute`s that decorate items and Attributes that
 /// are contained as statements within items. These two cases need to be
 /// distinguished for pretty-printing.
-#[derive(Clone, PartialEq, Eq, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy, HashStable_Generic, Walkable)]
-#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
 pub enum AttrStyle {
     Outer,
     Inner,
@@ -3397,7 +3360,7 @@ impl NormalAttr {
             item: AttrItem {
                 unsafety: Safety::Default,
                 path: Path::from_ident(ident),
-                args: AttrItemKind::Unparsed(AttrArgs::Empty),
+                args: AttrArgs::Empty,
                 tokens: None,
             },
             tokens: None,
@@ -3409,53 +3372,11 @@ impl NormalAttr {
 pub struct AttrItem {
     pub unsafety: Safety,
     pub path: Path,
-    pub args: AttrItemKind,
+    pub args: AttrArgs,
     // Tokens for the meta item, e.g. just the `foo` within `#[foo]` or `#![foo]`.
     pub tokens: Option<LazyAttrTokenStream>,
 }
 
-/// Some attributes are stored in a parsed form, for performance reasons.
-/// Their arguments don't have to be reparsed everytime they're used
-#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
-pub enum AttrItemKind {
-    Parsed(EarlyParsedAttribute),
-    Unparsed(AttrArgs),
-}
-
-impl AttrItemKind {
-    pub fn unparsed(self) -> Option<AttrArgs> {
-        match self {
-            AttrItemKind::Unparsed(args) => Some(args),
-            AttrItemKind::Parsed(_) => None,
-        }
-    }
-
-    pub fn unparsed_ref(&self) -> Option<&AttrArgs> {
-        match self {
-            AttrItemKind::Unparsed(args) => Some(args),
-            AttrItemKind::Parsed(_) => None,
-        }
-    }
-
-    pub fn span(&self) -> Option<Span> {
-        match self {
-            AttrItemKind::Unparsed(args) => args.span(),
-            AttrItemKind::Parsed(_) => None,
-        }
-    }
-}
-
-/// Some attributes are stored in parsed form in the AST.
-/// This is done for performance reasons, so the attributes don't need to be reparsed on every use.
-///
-/// Currently all early parsed attributes are excluded from pretty printing at rustc_ast_pretty::pprust::state::print_attribute_inline.
-/// When adding new early parsed attributes, consider whether they should be pretty printed.
-#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
-pub enum EarlyParsedAttribute {
-    CfgTrace(CfgEntry),
-    CfgAttrTrace,
-}
-
 impl AttrItem {
     pub fn is_valid_for_outer_style(&self) -> bool {
         self.path == sym::cfg_attr
@@ -3630,7 +3551,6 @@ impl Item {
     pub fn opt_generics(&self) -> Option<&Generics> {
         match &self.kind {
             ItemKind::ExternCrate(..)
-            | ItemKind::ConstBlock(_)
             | ItemKind::Use(_)
             | ItemKind::Mod(..)
             | ItemKind::ForeignMod(_)
@@ -3809,34 +3729,6 @@ pub struct Fn {
     pub contract: Option<Box<FnContract>>,
     pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
     pub body: Option<Box<Block>>,
-
-    /// This function is an implementation of an externally implementable item (EII).
-    /// This means, there was an EII declared somewhere and this function is the
-    /// implementation that should be run when the declaration is called.
-    pub eii_impls: ThinVec<EiiImpl>,
-}
-
-#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
-pub struct EiiImpl {
-    pub node_id: NodeId,
-    pub eii_macro_path: Path,
-    /// This field is an implementation detail that prevents a lot of bugs.
-    /// See <https://github.com/rust-lang/rust/issues/149981> for an example.
-    ///
-    /// The problem is, that if we generate a declaration *together* with its default,
-    /// we generate both a declaration and an implementation. The generated implementation
-    /// uses the same mechanism to register itself as a user-defined implementation would,
-    /// despite being invisible to users. What does happen is a name resolution step.
-    /// The invisible default implementation has to find the declaration.
-    /// Both are generated at the same time, so we can skip that name resolution step.
-    ///
-    /// This field is that shortcut: we prefill the extern target to skip a name resolution step,
-    /// making sure it never fails. It'd be awful UX if we fail name resolution in code invisible to the user.
-    pub known_eii_macro_resolution: Option<EiiDecl>,
-    pub impl_safety: Safety,
-    pub span: Span,
-    pub inner_span: Span,
-    pub is_default: bool,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug, Walkable)]
@@ -3877,55 +3769,27 @@ pub struct ConstItem {
     pub ident: Ident,
     pub generics: Generics,
     pub ty: Box<Ty>,
-    pub rhs_kind: ConstItemRhsKind,
+    pub rhs: Option<ConstItemRhs>,
     pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug, Walkable)]
-pub enum ConstItemRhsKind {
+pub enum ConstItemRhs {
-    Body { rhs: Option<Box<Expr>> },
+    TypeConst(AnonConst),
-    TypeConst { rhs: Option<AnonConst> },
+    Body(Box<Expr>),
 }
 
-impl ConstItemRhsKind {
+impl ConstItemRhs {
-    pub fn new_body(rhs: Box<Expr>) -> Self {
+    pub fn span(&self) -> Span {
-        Self::Body { rhs: Some(rhs) }
+        self.expr().span
     }
 
-    pub fn span(&self) -> Option<Span> {
+    pub fn expr(&self) -> &Expr {
-        Some(self.expr()?.span)
-    }
-
-    pub fn expr(&self) -> Option<&Expr> {
         match self {
-            Self::Body { rhs: Some(body) } => Some(&body),
+            ConstItemRhs::TypeConst(anon_const) => &anon_const.value,
-            Self::TypeConst { rhs: Some(anon) } => Some(&anon.value),
+            ConstItemRhs::Body(expr) => expr,
-            _ => None,
         }
     }
-
-    pub fn has_expr(&self) -> bool {
-        match self {
-            Self::Body { rhs: Some(_) } => true,
-            Self::TypeConst { rhs: Some(_) } => true,
-            _ => false,
-        }
-    }
-
-    pub fn is_type_const(&self) -> bool {
-        matches!(self, &Self::TypeConst { .. })
-    }
-}
-
-#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
-pub struct ConstBlockItem {
-    pub id: NodeId,
-    pub span: Span,
-    pub block: Box<Block>,
-}
-
-impl ConstBlockItem {
-    pub const IDENT: Ident = Ident { name: kw::Underscore, span: DUMMY_SP };
 }
 
 // Adding a new variant? Please update `test_item` in `tests/ui/macros/stringify.rs`.
@@ -3947,11 +3811,6 @@ pub enum ItemKind {
     ///
     /// E.g., `const FOO: i32 = 42;`.
     Const(Box<ConstItem>),
-    /// A module-level const block.
-    /// Equivalent to `const _: () = const { ... };`.
-    ///
-    /// E.g., `const { assert!(true) }`.
-    ConstBlock(ConstBlockItem),
     /// A function declaration (`fn`).
     ///
     /// E.g., `fn foo(bar: usize) -> usize { .. }`.
@@ -4028,8 +3887,6 @@ impl ItemKind {
             | ItemKind::MacroDef(ident, _)
             | ItemKind::Delegation(box Delegation { ident, .. }) => Some(ident),
 
-            ItemKind::ConstBlock(_) => Some(ConstBlockItem::IDENT),
-
             ItemKind::Use(_)
             | ItemKind::ForeignMod(_)
             | ItemKind::GlobalAsm(_)
@@ -4043,9 +3900,9 @@ impl ItemKind {
     pub fn article(&self) -> &'static str {
         use ItemKind::*;
         match self {
-            Use(..) | Static(..) | Const(..) | ConstBlock(..) | Fn(..) | Mod(..)
+            Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
-            | GlobalAsm(..) | TyAlias(..) | Struct(..) | Union(..) | Trait(..) | TraitAlias(..)
+            | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..)
-            | MacroDef(..) | Delegation(..) | DelegationMac(..) => "a",
+            | Delegation(..) | DelegationMac(..) => "a",
             ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
         }
     }
@@ -4056,7 +3913,6 @@ impl ItemKind {
             ItemKind::Use(..) => "`use` import",
             ItemKind::Static(..) => "static item",
             ItemKind::Const(..) => "constant item",
-            ItemKind::ConstBlock(..) => "const block",
             ItemKind::Fn(..) => "function",
             ItemKind::Mod(..) => "module",
             ItemKind::ForeignMod(..) => "extern block",
@@ -4086,18 +3942,7 @@ impl ItemKind {
             | Self::Trait(box Trait { generics, .. })
             | Self::TraitAlias(box TraitAlias { generics, .. })
             | Self::Impl(Impl { generics, .. }) => Some(generics),
-
+            _ => None,
-            Self::ExternCrate(..)
-            | Self::Use(..)
-            | Self::Static(..)
-            | Self::ConstBlock(..)
-            | Self::Mod(..)
-            | Self::ForeignMod(..)
-            | Self::GlobalAsm(..)
-            | Self::MacCall(..)
-            | Self::MacroDef(..)
-            | Self::Delegation(..)
-            | Self::DelegationMac(..) => None,
         }
     }
 }
@@ -4148,7 +3993,7 @@ impl AssocItemKind {
             | Self::Fn(box Fn { defaultness, .. })
             | Self::Type(box TyAlias { defaultness, .. }) => defaultness,
             Self::MacCall(..) | Self::Delegation(..) | Self::DelegationMac(..) => {
-                Defaultness::Implicit
+                Defaultness::Final
             }
         }
     }
@@ -4250,7 +4095,7 @@ mod size_asserts {
     static_assert_size!(Block, 32);
     static_assert_size!(Expr, 72);
     static_assert_size!(ExprKind, 40);
-    static_assert_size!(Fn, 192);
+    static_assert_size!(Fn, 184);
     static_assert_size!(ForeignItem, 80);
     static_assert_size!(ForeignItemKind, 16);
     static_assert_size!(GenericArg, 24);

compiler/rustc_ast/src/attr/data_structures.rs

@@ -1,101 +0,0 @@
-use std::fmt;
-
-use rustc_macros::{Decodable, Encodable, HashStable_Generic};
-use rustc_span::{Span, Symbol};
-use thin_vec::ThinVec;
-
-use crate::attr::version::RustcVersion;
-
-#[derive(Encodable, Decodable, Clone, Debug, PartialEq, Eq, Hash, HashStable_Generic)]
-pub enum CfgEntry {
-    All(ThinVec<CfgEntry>, Span),
-    Any(ThinVec<CfgEntry>, Span),
-    Not(Box<CfgEntry>, Span),
-    Bool(bool, Span),
-    NameValue { name: Symbol, value: Option<Symbol>, span: Span },
-    Version(Option<RustcVersion>, Span),
-}
-
-impl CfgEntry {
-    pub fn lower_spans(&mut self, lower_span: impl Copy + Fn(Span) -> Span) {
-        match self {
-            CfgEntry::All(subs, span) | CfgEntry::Any(subs, span) => {
-                *span = lower_span(*span);
-                subs.iter_mut().for_each(|sub| sub.lower_spans(lower_span));
-            }
-            CfgEntry::Not(sub, span) => {
-                *span = lower_span(*span);
-                sub.lower_spans(lower_span);
-            }
-            CfgEntry::Bool(_, span)
-            | CfgEntry::NameValue { span, .. }
-            | CfgEntry::Version(_, span) => {
-                *span = lower_span(*span);
-            }
-        }
-    }
-
-    pub fn span(&self) -> Span {
-        let (Self::All(_, span)
-        | Self::Any(_, span)
-        | Self::Not(_, span)
-        | Self::Bool(_, span)
-        | Self::NameValue { span, .. }
-        | Self::Version(_, span)) = self;
-        *span
-    }
-
-    /// Same as `PartialEq` but doesn't check spans and ignore order of cfgs.
-    pub fn is_equivalent_to(&self, other: &Self) -> bool {
-        match (self, other) {
-            (Self::All(a, _), Self::All(b, _)) | (Self::Any(a, _), Self::Any(b, _)) => {
-                a.len() == b.len() && a.iter().all(|a| b.iter().any(|b| a.is_equivalent_to(b)))
-            }
-            (Self::Not(a, _), Self::Not(b, _)) => a.is_equivalent_to(b),
-            (Self::Bool(a, _), Self::Bool(b, _)) => a == b,
-            (
-                Self::NameValue { name: name1, value: value1, .. },
-                Self::NameValue { name: name2, value: value2, .. },
-            ) => name1 == name2 && value1 == value2,
-            (Self::Version(a, _), Self::Version(b, _)) => a == b,
-            _ => false,
-        }
-    }
-}
-
-impl fmt::Display for CfgEntry {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fn write_entries(
-            name: &str,
-            entries: &[CfgEntry],
-            f: &mut fmt::Formatter<'_>,
-        ) -> fmt::Result {
-            write!(f, "{name}(")?;
-            for (nb, entry) in entries.iter().enumerate() {
-                if nb != 0 {
-                    f.write_str(", ")?;
-                }
-                entry.fmt(f)?;
-            }
-            f.write_str(")")
-        }
-        match self {
-            Self::All(entries, _) => write_entries("all", entries, f),
-            Self::Any(entries, _) => write_entries("any", entries, f),
-            Self::Not(entry, _) => write!(f, "not({entry})"),
-            Self::Bool(value, _) => write!(f, "{value}"),
-            Self::NameValue { name, value, .. } => {
-                match value {
-                    // We use `as_str` and debug display to have characters escaped and `"`
-                    // characters surrounding the string.
-                    Some(value) => write!(f, "{name} = {:?}", value.as_str()),
-                    None => write!(f, "{name}"),
-                }
-            }
-            Self::Version(version, _) => match version {
-                Some(version) => write!(f, "{version}"),
-                None => Ok(()),
-            },
-        }
-    }
-}

compiler/rustc_ast/src/attr/mod.rs

@@ -1,8 +1,5 @@
 //! Functions dealing with attributes and meta items.
 
-pub mod data_structures;
-pub mod version;
-
 use std::fmt::Debug;
 use std::sync::atomic::{AtomicU32, Ordering};
 
@@ -11,15 +8,12 @@ use rustc_span::{Ident, Span, Symbol, sym};
 use smallvec::{SmallVec, smallvec};
 use thin_vec::{ThinVec, thin_vec};
 
-use crate::AttrItemKind;
 use crate::ast::{
     AttrArgs, AttrId, AttrItem, AttrKind, AttrStyle, AttrVec, Attribute, DUMMY_NODE_ID, DelimArgs,
     Expr, ExprKind, LitKind, MetaItem, MetaItemInner, MetaItemKind, MetaItemLit, NormalAttr, Path,
     PathSegment, Safety,
 };
-use crate::token::{
+use crate::token::{self, CommentKind, Delimiter, InvisibleOrigin, MetaVarKind, Token};
-    self, CommentKind, Delimiter, DocFragmentKind, InvisibleOrigin, MetaVarKind, Token,
-};
 use crate::tokenstream::{
     DelimSpan, LazyAttrTokenStream, Spacing, TokenStream, TokenStreamIter, TokenTree,
 };
@@ -66,15 +60,6 @@ impl Attribute {
         }
     }
 
-    /// Replaces the arguments of this attribute with new arguments `AttrItemKind`.
-    /// This is useful for making this attribute into a trace attribute, and should otherwise be avoided.
-    pub fn replace_args(&mut self, new_args: AttrItemKind) {
-        match &mut self.kind {
-            AttrKind::Normal(normal) => normal.item.args = new_args,
-            AttrKind::DocComment(..) => panic!("unexpected doc comment"),
-        }
-    }
-
     pub fn unwrap_normal_item(self) -> AttrItem {
         match self.kind {
             AttrKind::Normal(normal) => normal.item,
@@ -90,7 +75,7 @@ impl AttributeExt for Attribute {
 
     fn value_span(&self) -> Option<Span> {
         match &self.kind {
-            AttrKind::Normal(normal) => match &normal.item.args.unparsed_ref()? {
+            AttrKind::Normal(normal) => match &normal.item.args {
                 AttrArgs::Eq { expr, .. } => Some(expr.span),
                 _ => None,
             },
@@ -109,11 +94,11 @@ impl AttributeExt for Attribute {
     }
 
     /// For a single-segment attribute, returns its name; otherwise, returns `None`.
-    fn name(&self) -> Option<Symbol> {
+    fn ident(&self) -> Option<Ident> {
         match &self.kind {
             AttrKind::Normal(normal) => {
                 if let [ident] = &*normal.item.path.segments {
-                    Some(ident.ident.name)
+                    Some(ident.ident)
                 } else {
                     None
                 }
@@ -122,18 +107,9 @@ impl AttributeExt for Attribute {
         }
     }
 
-    fn symbol_path(&self) -> Option<SmallVec<[Symbol; 1]>> {
+    fn ident_path(&self) -> Option<SmallVec<[Ident; 1]>> {
         match &self.kind {
-            AttrKind::Normal(p) => {
+            AttrKind::Normal(p) => Some(p.item.path.segments.iter().map(|i| i.ident).collect()),
-                Some(p.item.path.segments.iter().map(|i| i.ident.name).collect())
-            }
-            AttrKind::DocComment(_, _) => None,
-        }
-    }
-
-    fn path_span(&self) -> Option<Span> {
-        match &self.kind {
-            AttrKind::Normal(attr) => Some(attr.item.path.span),
             AttrKind::DocComment(_, _) => None,
         }
     }
@@ -160,7 +136,7 @@ impl AttributeExt for Attribute {
 
     fn is_word(&self) -> bool {
         if let AttrKind::Normal(normal) = &self.kind {
-            matches!(normal.item.args, AttrItemKind::Unparsed(AttrArgs::Empty))
+            matches!(normal.item.args, AttrArgs::Empty)
         } else {
             false
         }
@@ -203,21 +179,15 @@ impl AttributeExt for Attribute {
     }
 
     /// Returns the documentation and its kind if this is a doc comment or a sugared doc comment.
-    /// * `///doc` returns `Some(("doc", DocFragmentKind::Sugared(CommentKind::Line)))`.
+    /// * `///doc` returns `Some(("doc", CommentKind::Line))`.
-    /// * `/** doc */` returns `Some(("doc", DocFragmentKind::Sugared(CommentKind::Block)))`.
+    /// * `/** doc */` returns `Some(("doc", CommentKind::Block))`.
-    /// * `#[doc = "doc"]` returns `Some(("doc", DocFragmentKind::Raw))`.
+    /// * `#[doc = "doc"]` returns `Some(("doc", CommentKind::Line))`.
     /// * `#[doc(...)]` returns `None`.
-    fn doc_str_and_fragment_kind(&self) -> Option<(Symbol, DocFragmentKind)> {
+    fn doc_str_and_comment_kind(&self) -> Option<(Symbol, CommentKind)> {
         match &self.kind {
-            AttrKind::DocComment(kind, data) => Some((*data, DocFragmentKind::Sugared(*kind))),
+            AttrKind::DocComment(kind, data) => Some((*data, *kind)),
             AttrKind::Normal(normal) if normal.item.path == sym::doc => {
-                if let Some(value) = normal.item.value_str()
+                normal.item.value_str().map(|s| (s, CommentKind::Line))
-                    && let Some(value_span) = normal.item.value_span()
-                {
-                    Some((value, DocFragmentKind::Raw(value_span)))
-                } else {
-                    None
-                }
             }
             _ => None,
         }
@@ -235,34 +205,6 @@ impl AttributeExt for Attribute {
         }
     }
 
-    fn deprecation_note(&self) -> Option<Ident> {
-        match &self.kind {
-            AttrKind::Normal(normal) if normal.item.path == sym::deprecated => {
-                let meta = &normal.item;
-
-                // #[deprecated = "..."]
-                if let Some(s) = meta.value_str() {
-                    return Some(Ident { name: s, span: meta.span() });
-                }
-
-                // #[deprecated(note = "...")]
-                if let Some(list) = meta.meta_item_list() {
-                    for nested in list {
-                        if let Some(mi) = nested.meta_item()
-                            && mi.path == sym::note
-                            && let Some(s) = mi.value_str()
-                        {
-                            return Some(Ident { name: s, span: mi.span });
-                        }
-                    }
-                }
-
-                None
-            }
-            _ => None,
-        }
-    }
-
     fn doc_resolution_scope(&self) -> Option<AttrStyle> {
         match &self.kind {
             AttrKind::DocComment(..) => Some(self.style),
@@ -278,24 +220,6 @@ impl AttributeExt for Attribute {
     fn is_automatically_derived_attr(&self) -> bool {
         self.has_name(sym::automatically_derived)
     }
-
-    fn is_doc_hidden(&self) -> bool {
-        self.has_name(sym::doc)
-            && self.meta_item_list().is_some_and(|l| list_contains_name(&l, sym::hidden))
-    }
-
-    fn is_doc_keyword_or_attribute(&self) -> bool {
-        if self.has_name(sym::doc)
-            && let Some(items) = self.meta_item_list()
-        {
-            for item in items {
-                if item.has_name(sym::keyword) || item.has_name(sym::attribute) {
-                    return true;
-                }
-            }
-        }
-        false
-    }
 }
 
 impl Attribute {
@@ -305,7 +229,6 @@ impl Attribute {
 
     pub fn may_have_doc_links(&self) -> bool {
         self.doc_str().is_some_and(|s| comments::may_have_doc_links(s.as_str()))
-            || self.deprecation_note().is_some_and(|s| comments::may_have_doc_links(s.as_str()))
     }
 
     /// Extracts the MetaItem from inside this Attribute.
@@ -345,7 +268,7 @@ impl AttrItem {
     }
 
     pub fn meta_item_list(&self) -> Option<ThinVec<MetaItemInner>> {
-        match &self.args.unparsed_ref()? {
+        match &self.args {
             AttrArgs::Delimited(args) if args.delim == Delimiter::Parenthesis => {
                 MetaItemKind::list_from_tokens(args.tokens.clone())
             }
@@ -366,7 +289,7 @@ impl AttrItem {
     /// #[attr("value")]
     /// ```
     fn value_str(&self) -> Option<Symbol> {
-        match &self.args.unparsed_ref()? {
+        match &self.args {
             AttrArgs::Eq { expr, .. } => match expr.kind {
                 ExprKind::Lit(token_lit) => {
                     LitKind::from_token_lit(token_lit).ok().and_then(|lit| lit.str())
@@ -377,25 +300,6 @@ impl AttrItem {
         }
     }
 
-    /// Returns the span in:
-    ///
-    /// ```text
-    /// #[attribute = "value"]
-    ///               ^^^^^^^
-    /// ```
-    ///
-    /// It returns `None` in any other cases like:
-    ///
-    /// ```text
-    /// #[attr("value")]
-    /// ```
-    fn value_span(&self) -> Option<Span> {
-        match &self.args.unparsed_ref()? {
-            AttrArgs::Eq { expr, .. } => Some(expr.span),
-            AttrArgs::Delimited(_) | AttrArgs::Empty => None,
-        }
-    }
-
     pub fn meta(&self, span: Span) -> Option<MetaItem> {
         Some(MetaItem {
             unsafety: Safety::Default,
@@ -406,7 +310,7 @@ impl AttrItem {
     }
 
     pub fn meta_kind(&self) -> Option<MetaItemKind> {
-        MetaItemKind::from_attr_args(self.args.unparsed_ref()?)
+        MetaItemKind::from_attr_args(&self.args)
     }
 }
 
@@ -498,17 +402,20 @@ impl MetaItem {
                     thin_vec![PathSegment::path_root(span)]
                 };
                 loop {
-                    let Some(&TokenTree::Token(Token { kind: token::Ident(name, _), span }, _)) =
+                    if let Some(&TokenTree::Token(Token { kind: token::Ident(name, _), span }, _)) =
                         iter.next().map(|tt| TokenTree::uninterpolate(tt)).as_deref()
-                    else {
+                    {
+                        segments.push(PathSegment::from_ident(Ident::new(name, span)));
+                    } else {
                         return None;
-                    };
+                    }
-                    segments.push(PathSegment::from_ident(Ident::new(name, span)));
+                    if let Some(TokenTree::Token(Token { kind: token::PathSep, .. }, _)) =
-                    let Some(TokenTree::Token(Token { kind: token::PathSep, .. }, _)) = iter.peek()
+                        iter.peek()
-                    else {
+                    {
+                        iter.next();
+                    } else {
                         break;
-                    };
+                    }
-                    iter.next();
                 }
                 let span = span.with_hi(segments.last().unwrap().ident.span.hi());
                 Path { span, segments, tokens: None }
@@ -741,13 +648,7 @@ fn mk_attr(
     args: AttrArgs,
     span: Span,
 ) -> Attribute {
-    mk_attr_from_item(
+    mk_attr_from_item(g, AttrItem { unsafety, path, args, tokens: None }, None, style, span)
-        g,
-        AttrItem { unsafety, path, args: AttrItemKind::Unparsed(args), tokens: None },
-        None,
-        style,
-        span,
-    )
 }
 
 pub fn mk_attr_from_item(
@@ -851,7 +752,9 @@ pub trait AttributeExt: Debug {
 
     /// For a single-segment attribute (i.e., `#[attr]` and not `#[path::atrr]`),
     /// return the name of the attribute; otherwise, returns `None`.
-    fn name(&self) -> Option<Symbol>;
+    fn name(&self) -> Option<Symbol> {
+        self.ident().map(|ident| ident.name)
+    }
 
     /// Get the meta item list, `#[attr(meta item list)]`
     fn meta_item_list(&self) -> Option<ThinVec<MetaItemInner>>;
@@ -862,6 +765,9 @@ pub trait AttributeExt: Debug {
     /// Gets the span of the value literal, as string, when using `#[attr = value]`
     fn value_span(&self) -> Option<Span>;
 
+    /// For a single-segment attribute, returns its ident; otherwise, returns `None`.
+    fn ident(&self) -> Option<Ident>;
+
     /// Checks whether the path of this attribute matches the name.
     ///
     /// Matches one segment of the path to each element in `name`
@@ -874,7 +780,7 @@ pub trait AttributeExt: Debug {
 
     #[inline]
     fn has_name(&self, name: Symbol) -> bool {
-        self.name().map(|x| x == name).unwrap_or(false)
+        self.ident().map(|x| x.name == name).unwrap_or(false)
     }
 
     #[inline]
@@ -888,13 +794,13 @@ pub trait AttributeExt: Debug {
     fn is_word(&self) -> bool;
 
     fn path(&self) -> SmallVec<[Symbol; 1]> {
-        self.symbol_path().unwrap_or(smallvec![sym::doc])
+        self.ident_path()
+            .map(|i| i.into_iter().map(|i| i.name).collect())
+            .unwrap_or(smallvec![sym::doc])
     }
 
-    fn path_span(&self) -> Option<Span>;
-
     /// Returns None for doc comments
-    fn symbol_path(&self) -> Option<SmallVec<[Symbol; 1]>>;
+    fn ident_path(&self) -> Option<SmallVec<[Ident; 1]>>;
 
     /// Returns the documentation if this is a doc comment or a sugared doc comment.
     /// * `///doc` returns `Some("doc")`.
@@ -902,11 +808,6 @@ pub trait AttributeExt: Debug {
     /// * `#[doc(...)]` returns `None`.
     fn doc_str(&self) -> Option<Symbol>;
 
-    /// Returns the deprecation note if this is deprecation attribute.
-    /// * `#[deprecated = "note"]` returns `Some("note")`.
-    /// * `#[deprecated(note = "note", ...)]` returns `Some("note")`.
-    fn deprecation_note(&self) -> Option<Ident>;
-
     fn is_proc_macro_attr(&self) -> bool {
         [sym::proc_macro, sym::proc_macro_attribute, sym::proc_macro_derive]
             .iter()
@@ -919,7 +820,7 @@ pub trait AttributeExt: Debug {
     /// * `/** doc */` returns `Some(("doc", CommentKind::Block))`.
     /// * `#[doc = "doc"]` returns `Some(("doc", CommentKind::Line))`.
     /// * `#[doc(...)]` returns `None`.
-    fn doc_str_and_fragment_kind(&self) -> Option<(Symbol, DocFragmentKind)>;
+    fn doc_str_and_comment_kind(&self) -> Option<(Symbol, CommentKind)>;
 
     /// Returns outer or inner if this is a doc attribute or a sugared doc
     /// comment, otherwise None.
@@ -929,12 +830,6 @@ pub trait AttributeExt: Debug {
     /// commented module (for inner doc) vs within its parent module (for outer
     /// doc).
     fn doc_resolution_scope(&self) -> Option<AttrStyle>;
-
-    /// Returns `true` if this attribute contains `doc(hidden)`.
-    fn is_doc_hidden(&self) -> bool;
-
-    /// Returns `true` is this attribute contains `doc(keyword)` or `doc(attribute)`.
-    fn is_doc_keyword_or_attribute(&self) -> bool;
 }
 
 // FIXME(fn_delegation): use function delegation instead of manually forwarding
@@ -960,6 +855,10 @@ impl Attribute {
         AttributeExt::value_span(self)
     }
 
+    pub fn ident(&self) -> Option<Ident> {
+        AttributeExt::ident(self)
+    }
+
     pub fn path_matches(&self, name: &[Symbol]) -> bool {
         AttributeExt::path_matches(self, name)
     }
@@ -991,6 +890,10 @@ impl Attribute {
         AttributeExt::path(self)
     }
 
+    pub fn ident_path(&self) -> Option<SmallVec<[Ident; 1]>> {
+        AttributeExt::ident_path(self)
+    }
+
     pub fn doc_str(&self) -> Option<Symbol> {
         AttributeExt::doc_str(self)
     }
@@ -999,7 +902,7 @@ impl Attribute {
         AttributeExt::is_proc_macro_attr(self)
     }
 
-    pub fn doc_str_and_fragment_kind(&self) -> Option<(Symbol, DocFragmentKind)> {
+    pub fn doc_str_and_comment_kind(&self) -> Option<(Symbol, CommentKind)> {
-        AttributeExt::doc_str_and_fragment_kind(self)
+        AttributeExt::doc_str_and_comment_kind(self)
     }
 }

compiler/rustc_ast/src/attr/version.rs

@@ -1,43 +0,0 @@
-use std::fmt::{self, Display};
-use std::sync::OnceLock;
-
-use rustc_macros::{BlobDecodable, Encodable, HashStable_Generic, current_rustc_version};
-
-#[derive(Encodable, BlobDecodable, Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-#[derive(HashStable_Generic)]
-pub struct RustcVersion {
-    pub major: u16,
-    pub minor: u16,
-    pub patch: u16,
-}
-
-impl RustcVersion {
-    pub const CURRENT: Self = current_rustc_version!();
-    pub fn current_overridable() -> Self {
-        *CURRENT_OVERRIDABLE.get_or_init(|| {
-            if let Ok(override_var) = std::env::var("RUSTC_OVERRIDE_VERSION_STRING")
-                && let Some(override_) = Self::parse_str(&override_var)
-            {
-                override_
-            } else {
-                Self::CURRENT
-            }
-        })
-    }
-    fn parse_str(value: &str) -> Option<Self> {
-        // Ignore any suffixes such as "-dev" or "-nightly".
-        let mut components = value.split('-').next().unwrap().splitn(3, '.');
-        let major = components.next()?.parse().ok()?;
-        let minor = components.next()?.parse().ok()?;
-        let patch = components.next().unwrap_or("0").parse().ok()?;
-        Some(RustcVersion { major, minor, patch })
-    }
-}
-
-static CURRENT_OVERRIDABLE: OnceLock<RustcVersion> = OnceLock::new();
-
-impl Display for RustcVersion {
-    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(formatter, "{}.{}.{}", self.major, self.minor, self.patch)
-    }
-}

compiler/rustc_ast/src/lib.rs

@@ -6,6 +6,7 @@
 
 // tidy-alphabetical-start
 #![doc(test(attr(deny(warnings), allow(internal_features))))]
+#![feature(array_windows)]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]

compiler/rustc_ast/src/token.rs

@@ -16,37 +16,13 @@ use rustc_span::{Ident, Symbol};
 use crate::ast;
 use crate::util::case::Case;
 
-/// Represents the kind of doc comment it is, ie `///` or `#[doc = ""]`.
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
-#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
-pub enum DocFragmentKind {
-    /// A sugared doc comment: `///` or `//!` or `/**` or `/*!`.
-    Sugared(CommentKind),
-    /// A "raw" doc comment: `#[doc = ""]`. The `Span` represents the string literal.
-    Raw(Span),
-}
-
-impl DocFragmentKind {
-    pub fn is_sugared(self) -> bool {
-        matches!(self, Self::Sugared(_))
-    }
-
-    /// If it is `Sugared`, it will return its associated `CommentKind`, otherwise it will return
-    /// `CommentKind::Line`.
-    pub fn comment_kind(self) -> CommentKind {
-        match self {
-            Self::Sugared(kind) => kind,
-            Self::Raw(_) => CommentKind::Line,
-        }
-    }
-}
-
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum CommentKind {
     Line,
     Block,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Encodable, Decodable, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Debug, Encodable, Decodable, HashStable_Generic)]
 pub enum InvisibleOrigin {
     // From the expansion of a metavariable in a declarative macro.
     MetaVar(MetaVarKind),
@@ -123,7 +99,7 @@ impl fmt::Display for MetaVarKind {
 /// Describes how a sequence of token trees is delimited.
 /// Cannot use `proc_macro::Delimiter` directly because this
 /// structure should implement some additional traits.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+#[derive(Copy, Clone, Debug, PartialEq, Encodable, Decodable, HashStable_Generic)]
 pub enum Delimiter {
     /// `( ... )`
     Parenthesis,
@@ -186,7 +162,7 @@ impl Delimiter {
 // type. This means that float literals like `1f32` are classified by this type
 // as `Int`. Only upon conversion to `ast::LitKind` will such a literal be
 // given the `Float` kind.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, Debug, HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum LitKind {
     Bool, // AST only, must never appear in a `Token`
     Byte,
@@ -203,7 +179,7 @@ pub enum LitKind {
 }
 
 /// A literal token.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, Debug, HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct Lit {
     pub kind: LitKind,
     pub symbol: Symbol,
@@ -349,7 +325,7 @@ fn ident_can_begin_type(name: Symbol, span: Span, is_raw: IdentIsRaw) -> bool {
             .contains(&name)
 }
 
-#[derive(PartialEq, Eq, Encodable, Decodable, Hash, Debug, Copy, Clone, HashStable_Generic)]
+#[derive(PartialEq, Encodable, Decodable, Debug, Copy, Clone, HashStable_Generic)]
 pub enum IdentIsRaw {
     No,
     Yes,
@@ -376,7 +352,7 @@ impl From<bool> for IdentIsRaw {
     }
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, Debug, HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum TokenKind {
     /* Expression-operator symbols. */
     /// `=`
@@ -526,7 +502,7 @@ pub enum TokenKind {
     Eof,
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Encodable, Decodable, Debug, HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct Token {
     pub kind: TokenKind,
     pub span: Span,
@@ -625,12 +601,12 @@ impl TokenKind {
 }
 
 impl Token {
-    pub const fn new(kind: TokenKind, span: Span) -> Self {
+    pub fn new(kind: TokenKind, span: Span) -> Self {
         Token { kind, span }
     }
 
     /// Some token that will be thrown away later.
-    pub const fn dummy() -> Self {
+    pub fn dummy() -> Self {
         Token::new(TokenKind::Question, DUMMY_SP)
     }
 

compiler/rustc_ast/src/tokenstream.rs

@@ -5,7 +5,6 @@
 //! which are themselves a single [`Token`] or a `Delimited` subsequence of tokens.
 
 use std::borrow::Cow;
-use std::hash::Hash;
 use std::ops::Range;
 use std::sync::Arc;
 use std::{cmp, fmt, iter, mem};
@@ -23,7 +22,7 @@ use crate::token::{self, Delimiter, Token, TokenKind};
 use crate::{AttrVec, Attribute};
 
 /// Part of a `TokenStream`.
-#[derive(Debug, Clone, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+#[derive(Debug, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
 pub enum TokenTree {
     /// A single token. Should never be `OpenDelim` or `CloseDelim`, because
     /// delimiters are implicitly represented by `Delimited`.
@@ -354,13 +353,7 @@ fn make_attr_token_stream(
                         FrameData { open_delim_sp: Some((delim, span, spacing)), inner: vec![] },
                     ));
                 } else if let Some(delim) = kind.close_delim() {
-                    // If there's no matching opening delimiter, the token stream is malformed,
+                    let frame_data = mem::replace(&mut stack_top, stack_rest.pop().unwrap());
-                    // likely due to a improper delimiter positions in the source code.
-                    // It's not delimiter mismatch, and lexer can not detect it, so we just ignore it here.
-                    let Some(frame) = stack_rest.pop() else {
-                        return AttrTokenStream::new(stack_top.inner);
-                    };
-                    let frame_data = mem::replace(&mut stack_top, frame);
                     let (open_delim, open_sp, open_spacing) = frame_data.open_delim_sp.unwrap();
                     assert!(
                         open_delim.eq_ignoring_invisible_origin(&delim),
@@ -545,7 +538,7 @@ pub struct AttrsTarget {
 /// compound token. Used for conversions to `proc_macro::Spacing`. Also used to
 /// guide pretty-printing, which is where the `JointHidden` value (which isn't
 /// part of `proc_macro::Spacing`) comes in useful.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+#[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable, HashStable_Generic)]
 pub enum Spacing {
     /// The token cannot join with the following token to form a compound
     /// token.
@@ -602,7 +595,7 @@ pub enum Spacing {
 }
 
 /// A `TokenStream` is an abstract sequence of tokens, organized into [`TokenTree`]s.
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash, Encodable, Decodable)]
+#[derive(Clone, Debug, Default, Encodable, Decodable)]
 pub struct TokenStream(pub(crate) Arc<Vec<TokenTree>>);
 
 impl TokenStream {
@@ -818,6 +811,14 @@ impl TokenStream {
     }
 }
 
+impl PartialEq<TokenStream> for TokenStream {
+    fn eq(&self, other: &TokenStream) -> bool {
+        self.iter().eq(other.iter())
+    }
+}
+
+impl Eq for TokenStream {}
+
 impl FromIterator<TokenTree> for TokenStream {
     fn from_iter<I: IntoIterator<Item = TokenTree>>(iter: I) -> Self {
         TokenStream::new(iter.into_iter().collect::<Vec<TokenTree>>())
@@ -969,8 +970,7 @@ impl TokenCursor {
     }
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Copy, Clone, PartialEq, Encodable, Decodable, HashStable_Generic, Walkable)]
-#[derive(Encodable, Decodable, HashStable_Generic, Walkable)]
 pub struct DelimSpan {
     pub open: Span,
     pub close: Span,
@@ -994,7 +994,7 @@ impl DelimSpan {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
+#[derive(Copy, Clone, Debug, PartialEq, Encodable, Decodable, HashStable_Generic)]
 pub struct DelimSpacing {
     pub open: Spacing,
     pub close: Spacing,

compiler/rustc_ast/src/visit.rs

@@ -366,7 +366,6 @@ macro_rules! common_visitor_and_walkers {
             crate::token::LitKind,
             crate::tokenstream::LazyAttrTokenStream,
             crate::tokenstream::TokenStream,
-            EarlyParsedAttribute,
             Movability,
             Mutability,
             Pinnedness,
@@ -394,7 +393,6 @@ macro_rules! common_visitor_and_walkers {
             ThinVec<Pat>,
             ThinVec<Box<Ty>>,
             ThinVec<TyPat>,
-            ThinVec<EiiImpl>,
         );
 
         // This macro generates `impl Visitable` and `impl MutVisitable` that forward to `Walkable`
@@ -417,7 +415,6 @@ macro_rules! common_visitor_and_walkers {
             UnsafeBinderCastKind,
             BinOpKind,
             BlockCheckMode,
-            MgcaDisambiguation,
             BorrowKind,
             BoundAsyncness,
             BoundConstness,
@@ -425,9 +422,8 @@ macro_rules! common_visitor_and_walkers {
             ByRef,
             Closure,
             Const,
-            ConstBlockItem,
             ConstItem,
-            ConstItemRhsKind,
+            ConstItemRhs,
             Defaultness,
             Delegation,
             DelegationMac,
@@ -459,7 +455,6 @@ macro_rules! common_visitor_and_walkers {
             ModSpans,
             MutTy,
             NormalAttr,
-            AttrItemKind,
             Parens,
             ParenthesizedArgs,
             PatFieldsRest,
@@ -490,8 +485,6 @@ macro_rules! common_visitor_and_walkers {
             WhereEqPredicate,
             WhereRegionPredicate,
             YieldKind,
-            EiiDecl,
-            EiiImpl,
         );
 
         /// Each method of this trait is a hook to be potentially
@@ -826,8 +819,6 @@ macro_rules! common_visitor_and_walkers {
                         visit_visitable!($($mut)? vis, use_tree),
                     ItemKind::Static(item) =>
                         visit_visitable!($($mut)? vis, item),
-                    ItemKind::ConstBlock(item) =>
-                        visit_visitable!($($mut)? vis, item),
                     ItemKind::Const(item) =>
                         visit_visitable!($($mut)? vis, item),
                     ItemKind::Mod(safety, ident, mod_kind) =>
@@ -928,13 +919,13 @@ macro_rules! common_visitor_and_walkers {
                     _ctxt,
                     // Visibility is visited as a part of the item.
                     _vis,
-                    Fn { defaultness, ident, sig, generics, contract, body, define_opaque, eii_impls },
+                    Fn { defaultness, ident, sig, generics, contract, body, define_opaque },
                 ) => {
                     let FnSig { header, decl, span } = sig;
                     visit_visitable!($($mut)? vis,
                         defaultness, ident, header, generics, decl,
-                        contract, body, span, define_opaque, eii_impls
+                        contract, body, span, define_opaque
-                    );
+                    )
                 }
                 FnKind::Closure(binder, coroutine_kind, decl, body) =>
                     visit_visitable!($($mut)? vis, binder, coroutine_kind, decl, body),
@@ -1057,8 +1048,8 @@ macro_rules! common_visitor_and_walkers {
                     visit_visitable!($($mut)? vis, kind),
                 ExprKind::Try(subexpression) =>
                     visit_visitable!($($mut)? vis, subexpression),
-                ExprKind::TryBlock(body, optional_type) =>
+                ExprKind::TryBlock(body) =>
-                    visit_visitable!($($mut)? vis, body, optional_type),
+                    visit_visitable!($($mut)? vis, body),
                 ExprKind::Lit(token) =>
                     visit_visitable!($($mut)? vis, token),
                 ExprKind::IncludedBytes(bytes) =>

compiler/rustc_ast_lowering/Cargo.toml

@@ -15,6 +15,7 @@ rustc_attr_parsing = { path = "../rustc_attr_parsing" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
+rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }

compiler/rustc_ast_lowering/messages.ftl

@@ -0,0 +1,188 @@
+ast_lowering_abi_specified_multiple_times =
+    `{$prev_name}` ABI specified multiple times
+    .label = previously specified here
+    .note = these ABIs are equivalent on the current target
+
+ast_lowering_arbitrary_expression_in_pattern =
+    arbitrary expressions aren't allowed in patterns
+    .pattern_from_macro_note = the `expr` fragment specifier forces the metavariable's content to be an expression
+
+ast_lowering_argument = argument
+
+ast_lowering_assoc_ty_binding_in_dyn =
+    associated type bounds are not allowed in `dyn` types
+    .suggestion = use `impl Trait` to introduce a type instead
+
+ast_lowering_assoc_ty_parentheses =
+    parenthesized generic arguments cannot be used in associated type constraints
+
+ast_lowering_async_bound_not_on_trait =
+    `async` bound modifier only allowed on trait, not `{$descr}`
+
+ast_lowering_async_bound_only_for_fn_traits =
+    `async` bound modifier only allowed on `Fn`/`FnMut`/`FnOnce` traits
+
+ast_lowering_async_coroutines_not_supported =
+    `async` coroutines are not yet supported
+
+ast_lowering_att_syntax_only_x86 =
+    the `att_syntax` option is only supported on x86
+
+ast_lowering_await_only_in_async_fn_and_blocks =
+    `await` is only allowed inside `async` functions and blocks
+    .label = only allowed inside `async` functions and blocks
+
+ast_lowering_bad_return_type_notation_inputs =
+    argument types not allowed with return type notation
+    .suggestion = remove the input types
+
+ast_lowering_bad_return_type_notation_needs_dots = return type notation arguments must be elided with `..`
+    .suggestion = use the correct syntax by adding `..` to the arguments
+
+ast_lowering_bad_return_type_notation_output =
+    return type not allowed with return type notation
+ast_lowering_bad_return_type_notation_output_suggestion = use the right argument notation and remove the return type
+
+ast_lowering_bad_return_type_notation_position = return type notation not allowed in this position yet
+
+ast_lowering_clobber_abi_not_supported =
+    `clobber_abi` is not supported on this target
+
+ast_lowering_closure_cannot_be_static = closures cannot be static
+
+ast_lowering_coroutine_too_many_parameters =
+    too many parameters for a coroutine (expected 0 or 1 parameters)
+
+ast_lowering_default_field_in_tuple = default fields are not supported in tuple structs
+    .label = default fields are only supported on structs
+
+ast_lowering_does_not_support_modifiers =
+    the `{$class_name}` register class does not support template modifiers
+
+ast_lowering_extra_double_dot =
+    `..` can only be used once per {$ctx} pattern
+    .label = can only be used once per {$ctx} pattern
+
+ast_lowering_functional_record_update_destructuring_assignment =
+    functional record updates are not allowed in destructuring assignments
+    .suggestion = consider removing the trailing pattern
+
+ast_lowering_generic_param_default_in_binder =
+    defaults for generic parameters are not allowed in `for<...>` binders
+
+ast_lowering_generic_type_with_parentheses =
+    parenthesized type parameters may only be used with a `Fn` trait
+    .label = only `Fn` traits may use parentheses
+
+ast_lowering_inclusive_range_with_no_end = inclusive range with no end
+
+ast_lowering_inline_asm_unsupported_target =
+    inline assembly is unsupported on this target
+
+ast_lowering_invalid_abi =
+    invalid ABI: found `{$abi}`
+    .label = invalid ABI
+    .note = invoke `{$command}` for a full list of supported calling conventions
+
+ast_lowering_invalid_abi_clobber_abi =
+    invalid ABI for `clobber_abi`
+    .note = the following ABIs are supported on this target: {$supported_abis}
+
+ast_lowering_invalid_abi_suggestion = there's a similarly named valid ABI `{$suggestion}`
+
+ast_lowering_invalid_asm_template_modifier_const =
+    asm template modifiers are not allowed for `const` arguments
+
+ast_lowering_invalid_asm_template_modifier_label =
+    asm template modifiers are not allowed for `label` arguments
+
+ast_lowering_invalid_asm_template_modifier_reg_class =
+    invalid asm template modifier for this register class
+
+ast_lowering_invalid_asm_template_modifier_sym =
+    asm template modifiers are not allowed for `sym` arguments
+
+ast_lowering_invalid_legacy_const_generic_arg =
+    invalid argument to a legacy const generic: cannot have const blocks, closures, async blocks or items
+
+ast_lowering_invalid_legacy_const_generic_arg_suggestion =
+    try using a const generic argument instead
+
+ast_lowering_invalid_register =
+    invalid register `{$reg}`: {$error}
+
+ast_lowering_invalid_register_class =
+    invalid register class `{$reg_class}`: unknown register class
+    .note = the following register classes are supported on this target: {$supported_register_classes}
+
+ast_lowering_match_arm_with_no_body =
+    `match` arm with no body
+    .suggestion = add a body after the pattern
+
+ast_lowering_misplaced_double_dot =
+    `..` patterns are not allowed here
+    .note = only allowed in tuple, tuple struct, and slice patterns
+
+ast_lowering_misplaced_impl_trait =
+    `impl Trait` is not allowed in {$position}
+    .note = `impl Trait` is only allowed in arguments and return types of functions and methods
+
+ast_lowering_never_pattern_with_body =
+    a never pattern is always unreachable
+    .label = this will never be executed
+    .suggestion = remove this expression
+
+ast_lowering_never_pattern_with_guard =
+    a guard on a never pattern will never be run
+    .suggestion = remove this guard
+
+ast_lowering_no_precise_captures_on_apit = `use<...>` precise capturing syntax not allowed in argument-position `impl Trait`
+
+ast_lowering_previously_used_here = previously used here
+
+ast_lowering_register1 = register `{$reg1_name}`
+
+ast_lowering_register2 = register `{$reg2_name}`
+
+ast_lowering_register_class_only_clobber =
+    register class `{$reg_class_name}` can only be used as a clobber, not as an input or output
+ast_lowering_register_class_only_clobber_stable =
+    register class `{$reg_class_name}` can only be used as a clobber in stable
+
+ast_lowering_register_conflict =
+    register `{$reg1_name}` conflicts with register `{$reg2_name}`
+    .help = use `lateout` instead of `out` to avoid conflict
+
+ast_lowering_remove_parentheses = remove these parentheses
+
+ast_lowering_sub_tuple_binding =
+    `{$ident_name} @` is not allowed in a {$ctx}
+    .label = this is only allowed in slice patterns
+    .help = remove this and bind each tuple field independently
+
+ast_lowering_sub_tuple_binding_suggestion = if you don't need to use the contents of {$ident}, discard the tuple's remaining fields
+
+ast_lowering_support_modifiers =
+    the `{$class_name}` register class supports the following template modifiers: {$modifiers}
+
+ast_lowering_template_modifier = template modifier
+
+ast_lowering_this_not_async = this is not `async`
+
+ast_lowering_underscore_expr_lhs_assign =
+    in expressions, `_` can only be used on the left-hand side of an assignment
+    .label = `_` not allowed here
+
+ast_lowering_union_default_field_values = unions cannot have default field values
+
+ast_lowering_unstable_inline_assembly = inline assembly is not stable yet on this architecture
+ast_lowering_unstable_inline_assembly_label_operand_with_outputs =
+    using both label and output operands for inline assembly is unstable
+ast_lowering_unstable_may_unwind = the `may_unwind` option is unstable
+
+ast_lowering_use_angle_brackets = use angle brackets instead
+
+ast_lowering_yield = yield syntax is experimental
+ast_lowering_yield_in_closure =
+    `yield` can only be used in `#[coroutine]` closures, or `gen` blocks
+    .suggestion = use `#[coroutine]` to make this closure a coroutine

compiler/rustc_ast_lowering/src/asm.rs

@@ -3,7 +3,6 @@ use std::fmt::Write;
 
 use rustc_ast::*;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
-use rustc_errors::msg;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_session::parse::feature_err;
@@ -20,7 +19,8 @@ use super::errors::{
     RegisterConflict,
 };
 use crate::{
-    AllowReturnTypeNotation, ImplTraitContext, ImplTraitPosition, ParamMode, ResolverAstLoweringExt,
+    AllowReturnTypeNotation, ImplTraitContext, ImplTraitPosition, ParamMode,
+    ResolverAstLoweringExt, fluent_generated as fluent,
 };
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
@@ -51,23 +51,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     | asm::InlineAsmArch::LoongArch32
                     | asm::InlineAsmArch::LoongArch64
                     | asm::InlineAsmArch::S390x
-                    | asm::InlineAsmArch::PowerPC
-                    | asm::InlineAsmArch::PowerPC64
             );
-            if !is_stable
+            if !is_stable && !self.tcx.features().asm_experimental_arch() {
-                && !self.tcx.features().asm_experimental_arch()
-                && sp
-                    .ctxt()
-                    .outer_expn_data()
-                    .allow_internal_unstable
-                    .filter(|features| features.contains(&sym::asm_experimental_arch))
-                    .is_none()
-            {
                 feature_err(
                     &self.tcx.sess,
                     sym::asm_experimental_arch,
                     sp,
-                    msg!("inline assembly is not stable yet on this architecture"),
+                    fluent::ast_lowering_unstable_inline_assembly,
                 )
                 .emit();
             }
@@ -84,7 +74,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 &self.tcx.sess,
                 sym::asm_unwind,
                 sp,
-                msg!("the `may_unwind` option is unstable"),
+                fluent::ast_lowering_unstable_may_unwind,
             )
             .emit();
         }
@@ -499,7 +489,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     sess,
                     sym::asm_goto_with_outputs,
                     *op_sp,
-                    msg!("using both label and output operands for inline assembly is unstable"),
+                    fluent::ast_lowering_unstable_inline_assembly_label_operand_with_outputs,
                 )
                 .emit();
             }

compiler/rustc_ast_lowering/src/block.rs

@@ -98,7 +98,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // Let statements are allowed to have impl trait in bindings.
         let super_ = l.super_.map(|span| self.lower_span(span));
         let ty = l.ty.as_ref().map(|t| {
-            self.lower_ty_alloc(t, self.impl_trait_in_bindings_ctxt(ImplTraitPosition::Variable))
+            self.lower_ty(t, self.impl_trait_in_bindings_ctxt(ImplTraitPosition::Variable))
         });
         let init = l.kind.init().map(|init| self.lower_expr(init));
         let hir_id = self.lower_node_id(l.id);

compiler/rustc_ast_lowering/src/contract.rs

@@ -23,7 +23,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // The order in which things are lowered is important! I.e to
         // refer to variables in contract_decls from postcond/precond,
         // we must lower it first!
-        let contract_decls = self.lower_decls(contract);
+        let contract_decls = self.lower_stmts(&contract.declarations).0;
 
         match (&contract.requires, &contract.ensures) {
             (Some(req), Some(ens)) => {
@@ -124,18 +124,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn lower_decls(&mut self, contract: &rustc_ast::FnContract) -> &'hir [rustc_hir::Stmt<'hir>] {
-        let (decls, decls_tail) = self.lower_stmts(&contract.declarations);
-
-        if let Some(e) = decls_tail {
-            // include the tail expression in the declaration statements
-            let tail = self.stmt_expr(e.span, *e);
-            self.arena.alloc_from_iter(decls.into_iter().map(|d| *d).chain([tail].into_iter()))
-        } else {
-            decls
-        }
-    }
-
     /// Lower the precondition check intrinsic.
     fn lower_precond(&mut self, req: &Box<rustc_ast::Expr>) -> rustc_hir::Stmt<'hir> {
         let lowered_req = self.lower_expr_mut(&req);

compiler/rustc_ast_lowering/src/delegation.rs

@@ -43,21 +43,15 @@ use hir::def::{DefKind, PartialRes, Res};
 use hir::{BodyId, HirId};
 use rustc_abi::ExternAbi;
 use rustc_ast::*;
-use rustc_attr_parsing::{AttributeParser, ShouldEmit};
-use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::ErrorGuaranteed;
-use rustc_hir::Target;
+use rustc_hir::def_id::DefId;
-use rustc_hir::attrs::{AttributeKind, InlineAttr};
-use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::span_bug;
-use rustc_middle::ty::{Asyncness, DelegationAttrs, DelegationFnSigAttrs, ResolverAstLowering};
+use rustc_middle::ty::{Asyncness, ResolverAstLowering};
 use rustc_span::symbol::kw;
-use rustc_span::{DUMMY_SP, Ident, Span, Symbol};
+use rustc_span::{Ident, Span, Symbol};
-use smallvec::SmallVec;
 use {rustc_ast as ast, rustc_hir as hir};
 
 use super::{GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode};
-use crate::errors::{CycleInDelegationSignatureResolution, UnresolvedDelegationCallee};
 use crate::{AllowReturnTypeNotation, ImplTraitPosition, ResolverAstLoweringExt};
 
 pub(crate) struct DelegationResults<'hir> {
@@ -67,68 +61,6 @@ pub(crate) struct DelegationResults<'hir> {
     pub generics: &'hir hir::Generics<'hir>,
 }
 
-struct AttrAdditionInfo {
-    pub equals: fn(&hir::Attribute) -> bool,
-    pub kind: AttrAdditionKind,
-}
-
-enum AttrAdditionKind {
-    Default { factory: fn(Span) -> hir::Attribute },
-    Inherit { flag: DelegationFnSigAttrs, factory: fn(Span, &hir::Attribute) -> hir::Attribute },
-}
-
-const PARENT_ID: hir::ItemLocalId = hir::ItemLocalId::ZERO;
-
-static ATTRS_ADDITIONS: &[AttrAdditionInfo] = &[
-    AttrAdditionInfo {
-        equals: |a| matches!(a, hir::Attribute::Parsed(AttributeKind::MustUse { .. })),
-        kind: AttrAdditionKind::Inherit {
-            factory: |span, original_attr| {
-                let reason = match original_attr {
-                    hir::Attribute::Parsed(AttributeKind::MustUse { reason, .. }) => *reason,
-                    _ => None,
-                };
-
-                hir::Attribute::Parsed(AttributeKind::MustUse { span, reason })
-            },
-            flag: DelegationFnSigAttrs::MUST_USE,
-        },
-    },
-    AttrAdditionInfo {
-        equals: |a| matches!(a, hir::Attribute::Parsed(AttributeKind::Inline(..))),
-        kind: AttrAdditionKind::Default {
-            factory: |span| hir::Attribute::Parsed(AttributeKind::Inline(InlineAttr::Hint, span)),
-        },
-    },
-];
-
-type DelegationIdsVec = SmallVec<[DefId; 1]>;
-
-// As delegations can now refer to another delegation, we have a delegation path
-// of the following type: reuse (current delegation) <- reuse (delegee_id) <- ... <- reuse <- function (root_function_id).
-// In its most basic and widely used form: reuse (current delegation) <- function (delegee_id, root_function_id)
-struct DelegationIds {
-    path: DelegationIdsVec,
-}
-
-impl DelegationIds {
-    fn new(path: DelegationIdsVec) -> Self {
-        assert!(!path.is_empty());
-        Self { path }
-    }
-
-    // Id of the first function in (non)local crate that is being reused
-    fn root_function_id(&self) -> DefId {
-        *self.path.last().expect("Ids vector can't be empty")
-    }
-
-    // Id of the first definition which is being reused,
-    // can be either function, in this case `root_id == delegee_id`, or other delegation
-    fn delegee_id(&self) -> DefId {
-        *self.path.first().expect("Ids vector can't be empty")
-    }
-}
-
 impl<'hir> LoweringContext<'_, 'hir> {
     fn is_method(&self, def_id: DefId, span: Span) -> bool {
         match self.tcx.def_kind(def_id) {
@@ -149,50 +81,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &mut self,
         delegation: &Delegation,
         item_id: NodeId,
+        is_in_trait_impl: bool,
     ) -> DelegationResults<'hir> {
         let span = self.lower_span(delegation.path.segments.last().unwrap().ident.span);
-
+        let sig_id = self.get_delegation_sig_id(item_id, delegation.id, span, is_in_trait_impl);
-        // Delegation can be unresolved in illegal places such as function bodies in extern blocks (see #151356)
+        match sig_id {
-        let ids = if let Some(delegation_info) =
+            Ok(sig_id) => {
-            self.resolver.delegation_infos.get(&self.local_def_id(item_id))
+                let is_method = self.is_method(sig_id, span);
-        {
+                let (param_count, c_variadic) = self.param_count(sig_id);
-            self.get_delegation_ids(delegation_info.resolution_node, span)
+                let decl = self.lower_delegation_decl(sig_id, param_count, c_variadic, span);
-        } else {
+                let sig = self.lower_delegation_sig(sig_id, decl, span);
-            return self.generate_delegation_error(
-                self.dcx().span_delayed_bug(
-                    span,
-                    format!("LoweringContext: the delegation {:?} is unresolved", item_id),
-                ),
-                span,
-                delegation,
-            );
-        };
-
-        match ids {
-            Ok(ids) => {
-                self.add_attrs_if_needed(span, &ids);
-
-                let delegee_id = ids.delegee_id();
-                let root_function_id = ids.root_function_id();
-
-                // `is_method` is used to choose the name of the first parameter (`self` or `arg0`),
-                // if the original function is not a method (without `self`), then it can not be added
-                // during chain of reuses, so we use `root_function_id` here
-                let is_method = self.is_method(root_function_id, span);
-
-                // Here we use `root_function_id` as we can not get params information out of potential delegation reuse,
-                // we need a function to extract this information
-                let (param_count, c_variadic) = self.param_count(root_function_id);
-
-                // Here we use `delegee_id`, as this id will then be used to calculate parent for generics
-                // inheritance, and we want this id to point on a delegee, not on the original
-                // function (see https://github.com/rust-lang/rust/issues/150152#issuecomment-3674834654)
-                let decl = self.lower_delegation_decl(delegee_id, param_count, c_variadic, span);
-
-                // Here we pass `root_function_id` as we want to inherit signature (including consts, async)
-                // from the root function that started delegation
-                let sig = self.lower_delegation_sig(root_function_id, decl, span);
-
                 let body_id = self.lower_delegation_body(delegation, is_method, param_count, span);
                 let ident = self.lower_ident(delegation.ident);
                 let generics = self.lower_delegation_generics(span);
@@ -202,163 +100,26 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    fn add_attrs_if_needed(&mut self, span: Span, ids: &DelegationIds) {
+    fn get_delegation_sig_id(
-        let new_attrs =
-            self.create_new_attrs(ATTRS_ADDITIONS, span, ids, self.attrs.get(&PARENT_ID));
-
-        if new_attrs.is_empty() {
-            return;
-        }
-
-        let new_arena_allocated_attrs = match self.attrs.get(&PARENT_ID) {
-            Some(existing_attrs) => self.arena.alloc_from_iter(
-                existing_attrs.iter().map(|a| a.clone()).chain(new_attrs.into_iter()),
-            ),
-            None => self.arena.alloc_from_iter(new_attrs.into_iter()),
-        };
-
-        self.attrs.insert(PARENT_ID, new_arena_allocated_attrs);
-    }
-
-    fn create_new_attrs(
         &self,
-        candidate_additions: &[AttrAdditionInfo],
+        item_id: NodeId,
+        path_id: NodeId,
         span: Span,
-        ids: &DelegationIds,
+        is_in_trait_impl: bool,
-        existing_attrs: Option<&&[hir::Attribute]>,
+    ) -> Result<DefId, ErrorGuaranteed> {
-    ) -> Vec<hir::Attribute> {
+        let sig_id = if is_in_trait_impl { item_id } else { path_id };
-        let defs_orig_attrs = ids
+        self.get_resolution_id(sig_id, span)
-            .path
-            .iter()
-            .map(|def_id| (*def_id, self.parse_local_original_attrs(*def_id)))
-            .collect::<Vec<_>>();
-
-        candidate_additions
-            .iter()
-            .filter_map(|addition_info| {
-                if let Some(existing_attrs) = existing_attrs
-                    && existing_attrs
-                        .iter()
-                        .any(|existing_attr| (addition_info.equals)(existing_attr))
-                {
-                    return None;
-                }
-
-                match addition_info.kind {
-                    AttrAdditionKind::Default { factory } => Some(factory(span)),
-                    AttrAdditionKind::Inherit { flag, factory } => {
-                        for (def_id, orig_attrs) in &defs_orig_attrs {
-                            let original_attr = match def_id.as_local() {
-                                Some(local_id) => self
-                                    .get_attrs(local_id)
-                                    .flags
-                                    .contains(flag)
-                                    .then(|| {
-                                        orig_attrs
-                                            .as_ref()
-                                            .map(|attrs| {
-                                                attrs.iter().find(|base_attr| {
-                                                    (addition_info.equals)(base_attr)
-                                                })
-                                            })
-                                            .flatten()
-                                    })
-                                    .flatten(),
-                                None => self
-                                    .tcx
-                                    .get_all_attrs(*def_id)
-                                    .iter()
-                                    .find(|base_attr| (addition_info.equals)(base_attr)),
-                            };
-
-                            if let Some(original_attr) = original_attr {
-                                return Some(factory(span, original_attr));
-                            }
-                        }
-
-                        None
-                    }
-                }
-            })
-            .collect::<Vec<_>>()
     }
 
-    fn parse_local_original_attrs(&self, def_id: DefId) -> Option<Vec<hir::Attribute>> {
+    fn get_resolution_id(&self, node_id: NodeId, span: Span) -> Result<DefId, ErrorGuaranteed> {
-        if let Some(local_id) = def_id.as_local() {
+        let def_id =
-            let attrs = &self.get_attrs(local_id).to_inherit;
+            self.resolver.get_partial_res(node_id).and_then(|r| r.expect_full_res().opt_def_id());
-
+        def_id.ok_or_else(|| {
-            if !attrs.is_empty() {
+            self.tcx.dcx().span_delayed_bug(
-                return Some(AttributeParser::parse_limited_all(
+                span,
-                    self.tcx.sess,
+                format!("LoweringContext: couldn't resolve node {:?} in delegation item", node_id),
-                    attrs,
+            )
-                    None,
+        })
-                    Target::Fn,
-                    DUMMY_SP,
-                    DUMMY_NODE_ID,
-                    Some(self.tcx.features()),
-                    ShouldEmit::Nothing,
-                ));
-            }
-        }
-
-        None
-    }
-
-    fn get_attrs(&self, local_id: LocalDefId) -> &DelegationAttrs {
-        // local_id can correspond either to a function or other delegation
-        if let Some(fn_sig) = self.resolver.delegation_fn_sigs.get(&local_id) {
-            &fn_sig.attrs
-        } else {
-            &self.resolver.delegation_infos[&local_id].attrs
-        }
-    }
-
-    fn get_delegation_ids(
-        &self,
-        mut node_id: NodeId,
-        span: Span,
-    ) -> Result<DelegationIds, ErrorGuaranteed> {
-        let mut visited: FxHashSet<NodeId> = Default::default();
-        let mut path: DelegationIdsVec = Default::default();
-
-        loop {
-            visited.insert(node_id);
-
-            let Some(def_id) = self.get_resolution_id(node_id) else {
-                return Err(self.tcx.dcx().span_delayed_bug(
-                    span,
-                    format!(
-                        "LoweringContext: couldn't resolve node {:?} in delegation item",
-                        node_id
-                    ),
-                ));
-            };
-
-            path.push(def_id);
-
-            // If def_id is in local crate and it corresponds to another delegation
-            // it means that we refer to another delegation as a callee, so in order to obtain
-            // a signature DefId we obtain NodeId of the callee delegation and try to get signature from it.
-            if let Some(local_id) = def_id.as_local()
-                && let Some(delegation_info) = self.resolver.delegation_infos.get(&local_id)
-            {
-                node_id = delegation_info.resolution_node;
-                if visited.contains(&node_id) {
-                    // We encountered a cycle in the resolution, or delegation callee refers to non-existent
-                    // entity, in this case emit an error.
-                    return Err(match visited.len() {
-                        1 => self.dcx().emit_err(UnresolvedDelegationCallee { span }),
-                        _ => self.dcx().emit_err(CycleInDelegationSignatureResolution { span }),
-                    });
-                }
-            } else {
-                return Ok(DelegationIds::new(path));
-            }
-        }
-    }
-
-    fn get_resolution_id(&self, node_id: NodeId) -> Option<DefId> {
-        self.resolver.get_partial_res(node_id).and_then(|r| r.expect_full_res().opt_def_id())
     }
 
     fn lower_delegation_generics(&mut self, span: Span) -> &'hir hir::Generics<'hir> {
@@ -372,14 +133,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     // Function parameter count, including C variadic `...` if present.
-    fn param_count(&self, def_id: DefId) -> (usize, bool /*c_variadic*/) {
+    fn param_count(&self, sig_id: DefId) -> (usize, bool /*c_variadic*/) {
-        if let Some(local_sig_id) = def_id.as_local() {
+        if let Some(local_sig_id) = sig_id.as_local() {
+            // Map may be filled incorrectly due to recursive delegation.
+            // Error will be emitted later during HIR ty lowering.
             match self.resolver.delegation_fn_sigs.get(&local_sig_id) {
                 Some(sig) => (sig.param_count, sig.c_variadic),
                 None => (0, false),
             }
         } else {
-            let sig = self.tcx.fn_sig(def_id).skip_binder().skip_binder();
+            let sig = self.tcx.fn_sig(sig_id).skip_binder().skip_binder();
             (sig.inputs().len() + usize::from(sig.c_variadic), sig.c_variadic)
         }
     }
@@ -429,9 +192,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     // We are not forwarding the attributes, as the delegation fn sigs are collected on the ast,
                     // and here we need the hir attributes.
                     let default_safety =
-                        if sig.attrs.flags.contains(DelegationFnSigAttrs::TARGET_FEATURE)
+                        if sig.target_feature || self.tcx.def_kind(parent) == DefKind::ForeignMod {
-                            || self.tcx.def_kind(parent) == DefKind::ForeignMod
-                        {
                             hir::Safety::Unsafe
                         } else {
                             hir::Safety::Safe
@@ -590,8 +351,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
             delegation.path.segments.iter().rev().skip(1).any(|segment| segment.args.is_some());
 
         let call = if self
-            .get_resolution_id(delegation.id)
+            .get_resolution_id(delegation.id, span)
-            .map(|def_id| self.is_method(def_id, span))
+            .and_then(|def_id| Ok(self.is_method(def_id, span)))
             .unwrap_or_default()
             && delegation.qself.is_none()
             && !has_generic_args

compiler/rustc_ast_lowering/src/errors.rs

@@ -4,17 +4,17 @@ use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Ident, Span, Symbol};
 
 #[derive(Diagnostic)]
-#[diag("parenthesized type parameters may only be used with a `Fn` trait", code = E0214)]
+#[diag(ast_lowering_generic_type_with_parentheses, code = E0214)]
 pub(crate) struct GenericTypeWithParentheses {
     #[primary_span]
-    #[label("only `Fn` traits may use parentheses")]
+    #[label]
     pub span: Span,
     #[subdiagnostic]
     pub sub: Option<UseAngleBrackets>,
 }
 
 #[derive(Subdiagnostic)]
-#[multipart_suggestion("use angle brackets instead", applicability = "maybe-incorrect")]
+#[multipart_suggestion(ast_lowering_use_angle_brackets, applicability = "maybe-incorrect")]
 pub(crate) struct UseAngleBrackets {
     #[suggestion_part(code = "<")]
     pub open_param: Span,
@@ -23,11 +23,11 @@ pub(crate) struct UseAngleBrackets {
 }
 
 #[derive(Diagnostic)]
-#[diag("invalid ABI: found `{$abi}`", code = E0703)]
+#[diag(ast_lowering_invalid_abi, code = E0703)]
-#[note("invoke `{$command}` for a full list of supported calling conventions")]
+#[note]
 pub(crate) struct InvalidAbi {
     #[primary_span]
-    #[label("invalid ABI")]
+    #[label]
     pub span: Span,
     pub abi: Symbol,
     pub command: String,
@@ -36,16 +36,16 @@ pub(crate) struct InvalidAbi {
 }
 
 #[derive(Diagnostic)]
-#[diag("default fields are not supported in tuple structs")]
+#[diag(ast_lowering_default_field_in_tuple)]
 pub(crate) struct TupleStructWithDefault {
     #[primary_span]
-    #[label("default fields are only supported on structs")]
+    #[label]
     pub span: Span,
 }
 
 #[derive(Subdiagnostic)]
 #[suggestion(
-    "there's a similarly named valid ABI `{$suggestion}`",
+    ast_lowering_invalid_abi_suggestion,
     code = "\"{suggestion}\"",
     applicability = "maybe-incorrect",
     style = "verbose"
@@ -57,7 +57,7 @@ pub(crate) struct InvalidAbiSuggestion {
 }
 
 #[derive(Diagnostic)]
-#[diag("parenthesized generic arguments cannot be used in associated type constraints")]
+#[diag(ast_lowering_assoc_ty_parentheses)]
 pub(crate) struct AssocTyParentheses {
     #[primary_span]
     pub span: Span,
@@ -67,12 +67,12 @@ pub(crate) struct AssocTyParentheses {
 
 #[derive(Subdiagnostic)]
 pub(crate) enum AssocTyParenthesesSub {
-    #[multipart_suggestion("remove these parentheses")]
+    #[multipart_suggestion(ast_lowering_remove_parentheses)]
     Empty {
         #[suggestion_part(code = "")]
         parentheses_span: Span,
     },
-    #[multipart_suggestion("use angle brackets instead")]
+    #[multipart_suggestion(ast_lowering_use_angle_brackets)]
     NotEmpty {
         #[suggestion_part(code = "<")]
         open_param: Span,
@@ -82,8 +82,8 @@ pub(crate) enum AssocTyParenthesesSub {
 }
 
 #[derive(Diagnostic)]
-#[diag("`impl Trait` is not allowed in {$position}", code = E0562)]
+#[diag(ast_lowering_misplaced_impl_trait, code = E0562)]
-#[note("`impl Trait` is only allowed in arguments and return types of functions and methods")]
+#[note]
 pub(crate) struct MisplacedImplTrait<'a> {
     #[primary_span]
     pub span: Span,
@@ -91,106 +91,97 @@ pub(crate) struct MisplacedImplTrait<'a> {
 }
 
 #[derive(Diagnostic)]
-#[diag("associated type bounds are not allowed in `dyn` types")]
+#[diag(ast_lowering_assoc_ty_binding_in_dyn)]
 pub(crate) struct MisplacedAssocTyBinding {
     #[primary_span]
     pub span: Span,
-    #[suggestion(
+    #[suggestion(code = " = impl", applicability = "maybe-incorrect", style = "verbose")]
-        "use `impl Trait` to introduce a type instead",
-        code = " = impl",
-        applicability = "maybe-incorrect",
-        style = "verbose"
-    )]
     pub suggestion: Option<Span>,
 }
 
 #[derive(Diagnostic)]
-#[diag("in expressions, `_` can only be used on the left-hand side of an assignment")]
+#[diag(ast_lowering_underscore_expr_lhs_assign)]
 pub(crate) struct UnderscoreExprLhsAssign {
     #[primary_span]
-    #[label("`_` not allowed here")]
+    #[label]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`await` is only allowed inside `async` functions and blocks", code = E0728)]
+#[diag(ast_lowering_await_only_in_async_fn_and_blocks, code = E0728)]
 pub(crate) struct AwaitOnlyInAsyncFnAndBlocks {
     #[primary_span]
-    #[label("only allowed inside `async` functions and blocks")]
+    #[label]
     pub await_kw_span: Span,
-    #[label("this is not `async`")]
+    #[label(ast_lowering_this_not_async)]
     pub item_span: Option<Span>,
 }
 
 #[derive(Diagnostic)]
-#[diag("too many parameters for a coroutine (expected 0 or 1 parameters)", code = E0628)]
+#[diag(ast_lowering_coroutine_too_many_parameters, code = E0628)]
 pub(crate) struct CoroutineTooManyParameters {
     #[primary_span]
     pub fn_decl_span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("closures cannot be static", code = E0697)]
+#[diag(ast_lowering_closure_cannot_be_static, code = E0697)]
 pub(crate) struct ClosureCannotBeStatic {
     #[primary_span]
     pub fn_decl_span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("functional record updates are not allowed in destructuring assignments")]
+#[diag(ast_lowering_functional_record_update_destructuring_assignment)]
 pub(crate) struct FunctionalRecordUpdateDestructuringAssignment {
     #[primary_span]
-    #[suggestion(
+    #[suggestion(code = "", applicability = "machine-applicable")]
-        "consider removing the trailing pattern",
-        code = "",
-        applicability = "machine-applicable"
-    )]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`async` coroutines are not yet supported", code = E0727)]
+#[diag(ast_lowering_async_coroutines_not_supported, code = E0727)]
 pub(crate) struct AsyncCoroutinesNotSupported {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("inline assembly is unsupported on this target", code = E0472)]
+#[diag(ast_lowering_inline_asm_unsupported_target, code = E0472)]
 pub(crate) struct InlineAsmUnsupportedTarget {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("the `att_syntax` option is only supported on x86")]
+#[diag(ast_lowering_att_syntax_only_x86)]
 pub(crate) struct AttSyntaxOnlyX86 {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`{$prev_name}` ABI specified multiple times")]
+#[diag(ast_lowering_abi_specified_multiple_times)]
 pub(crate) struct AbiSpecifiedMultipleTimes {
     #[primary_span]
     pub abi_span: Span,
     pub prev_name: Symbol,
-    #[label("previously specified here")]
+    #[label]
     pub prev_span: Span,
-    #[note("these ABIs are equivalent on the current target")]
+    #[note]
     pub equivalent: bool,
 }
 
 #[derive(Diagnostic)]
-#[diag("`clobber_abi` is not supported on this target")]
+#[diag(ast_lowering_clobber_abi_not_supported)]
 pub(crate) struct ClobberAbiNotSupported {
     #[primary_span]
     pub abi_span: Span,
 }
 
 #[derive(Diagnostic)]
-#[note("the following ABIs are supported on this target: {$supported_abis}")]
+#[note]
-#[diag("invalid ABI for `clobber_abi`")]
+#[diag(ast_lowering_invalid_abi_clobber_abi)]
 pub(crate) struct InvalidAbiClobberAbi {
     #[primary_span]
     pub abi_span: Span,
@@ -198,7 +189,7 @@ pub(crate) struct InvalidAbiClobberAbi {
 }
 
 #[derive(Diagnostic)]
-#[diag("invalid register `{$reg}`: {$error}")]
+#[diag(ast_lowering_invalid_register)]
 pub(crate) struct InvalidRegister<'a> {
     #[primary_span]
     pub op_span: Span,
@@ -207,10 +198,8 @@ pub(crate) struct InvalidRegister<'a> {
 }
 
 #[derive(Diagnostic)]
-#[note(
+#[note]
-    "the following register classes are supported on this target: {$supported_register_classes}"
+#[diag(ast_lowering_invalid_register_class)]
-)]
-#[diag("invalid register class `{$reg_class}`: unknown register class")]
 pub(crate) struct InvalidRegisterClass {
     #[primary_span]
     pub op_span: Span,
@@ -219,12 +208,12 @@ pub(crate) struct InvalidRegisterClass {
 }
 
 #[derive(Diagnostic)]
-#[diag("invalid asm template modifier for this register class")]
+#[diag(ast_lowering_invalid_asm_template_modifier_reg_class)]
 pub(crate) struct InvalidAsmTemplateModifierRegClass {
     #[primary_span]
-    #[label("template modifier")]
+    #[label(ast_lowering_template_modifier)]
     pub placeholder_span: Span,
-    #[label("argument")]
+    #[label(ast_lowering_argument)]
     pub op_span: Span,
     #[subdiagnostic]
     pub sub: InvalidAsmTemplateModifierRegClassSub,
@@ -232,48 +221,44 @@ pub(crate) struct InvalidAsmTemplateModifierRegClass {
 
 #[derive(Subdiagnostic)]
 pub(crate) enum InvalidAsmTemplateModifierRegClassSub {
-    #[note(
+    #[note(ast_lowering_support_modifiers)]
-        "the `{$class_name}` register class supports the following template modifiers: {$modifiers}"
-    )]
     SupportModifier { class_name: Symbol, modifiers: String },
-    #[note("the `{$class_name}` register class does not support template modifiers")]
+    #[note(ast_lowering_does_not_support_modifiers)]
     DoesNotSupportModifier { class_name: Symbol },
 }
 
 #[derive(Diagnostic)]
-#[diag("asm template modifiers are not allowed for `const` arguments")]
+#[diag(ast_lowering_invalid_asm_template_modifier_const)]
 pub(crate) struct InvalidAsmTemplateModifierConst {
     #[primary_span]
-    #[label("template modifier")]
+    #[label(ast_lowering_template_modifier)]
     pub placeholder_span: Span,
-    #[label("argument")]
+    #[label(ast_lowering_argument)]
     pub op_span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("asm template modifiers are not allowed for `sym` arguments")]
+#[diag(ast_lowering_invalid_asm_template_modifier_sym)]
 pub(crate) struct InvalidAsmTemplateModifierSym {
     #[primary_span]
-    #[label("template modifier")]
+    #[label(ast_lowering_template_modifier)]
     pub placeholder_span: Span,
-    #[label("argument")]
+    #[label(ast_lowering_argument)]
     pub op_span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("asm template modifiers are not allowed for `label` arguments")]
+#[diag(ast_lowering_invalid_asm_template_modifier_label)]
 pub(crate) struct InvalidAsmTemplateModifierLabel {
     #[primary_span]
-    #[label("template modifier")]
+    #[label(ast_lowering_template_modifier)]
     pub placeholder_span: Span,
-    #[label("argument")]
+    #[label(ast_lowering_argument)]
     pub op_span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag(
+#[diag(ast_lowering_register_class_only_clobber)]
-    "register class `{$reg_class_name}` can only be used as a clobber, not as an input or output"
-)]
 pub(crate) struct RegisterClassOnlyClobber {
     #[primary_span]
     pub op_span: Span,
@@ -281,7 +266,7 @@ pub(crate) struct RegisterClassOnlyClobber {
 }
 
 #[derive(Diagnostic)]
-#[diag("register class `{$reg_class_name}` can only be used as a clobber in stable")]
+#[diag(ast_lowering_register_class_only_clobber_stable)]
 pub(crate) struct RegisterClassOnlyClobberStable {
     #[primary_span]
     pub op_span: Span,
@@ -289,27 +274,27 @@ pub(crate) struct RegisterClassOnlyClobberStable {
 }
 
 #[derive(Diagnostic)]
-#[diag("register `{$reg1_name}` conflicts with register `{$reg2_name}`")]
+#[diag(ast_lowering_register_conflict)]
 pub(crate) struct RegisterConflict<'a> {
     #[primary_span]
-    #[label("register `{$reg1_name}`")]
+    #[label(ast_lowering_register1)]
     pub op_span1: Span,
-    #[label("register `{$reg2_name}`")]
+    #[label(ast_lowering_register2)]
     pub op_span2: Span,
     pub reg1_name: &'a str,
     pub reg2_name: &'a str,
-    #[help("use `lateout` instead of `out` to avoid conflict")]
+    #[help]
     pub in_out: Option<Span>,
 }
 
 #[derive(Diagnostic)]
-#[help("remove this and bind each tuple field independently")]
+#[help]
-#[diag("`{$ident_name} @` is not allowed in a {$ctx}")]
+#[diag(ast_lowering_sub_tuple_binding)]
 pub(crate) struct SubTupleBinding<'a> {
     #[primary_span]
-    #[label("this is only allowed in slice patterns")]
+    #[label]
     #[suggestion(
-        "if you don't need to use the contents of {$ident}, discard the tuple's remaining fields",
+        ast_lowering_sub_tuple_binding_suggestion,
         style = "verbose",
         code = "..",
         applicability = "maybe-incorrect"
@@ -321,67 +306,61 @@ pub(crate) struct SubTupleBinding<'a> {
 }
 
 #[derive(Diagnostic)]
-#[diag("`..` can only be used once per {$ctx} pattern")]
+#[diag(ast_lowering_extra_double_dot)]
 pub(crate) struct ExtraDoubleDot<'a> {
     #[primary_span]
-    #[label("can only be used once per {$ctx} pattern")]
+    #[label]
     pub span: Span,
-    #[label("previously used here")]
+    #[label(ast_lowering_previously_used_here)]
     pub prev_span: Span,
     pub ctx: &'a str,
 }
 
 #[derive(Diagnostic)]
-#[note("only allowed in tuple, tuple struct, and slice patterns")]
+#[note]
-#[diag("`..` patterns are not allowed here")]
+#[diag(ast_lowering_misplaced_double_dot)]
 pub(crate) struct MisplacedDoubleDot {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`match` arm with no body")]
+#[diag(ast_lowering_match_arm_with_no_body)]
 pub(crate) struct MatchArmWithNoBody {
     #[primary_span]
     pub span: Span,
-    #[suggestion(
+    #[suggestion(code = " => todo!(),", applicability = "has-placeholders")]
-        "add a body after the pattern",
-        code = " => todo!(),",
-        applicability = "has-placeholders"
-    )]
     pub suggestion: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("a never pattern is always unreachable")]
+#[diag(ast_lowering_never_pattern_with_body)]
 pub(crate) struct NeverPatternWithBody {
     #[primary_span]
-    #[label("this will never be executed")]
+    #[label]
-    #[suggestion("remove this expression", code = "", applicability = "maybe-incorrect")]
+    #[suggestion(code = "", applicability = "maybe-incorrect")]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("a guard on a never pattern will never be run")]
+#[diag(ast_lowering_never_pattern_with_guard)]
 pub(crate) struct NeverPatternWithGuard {
     #[primary_span]
-    #[suggestion("remove this guard", code = "", applicability = "maybe-incorrect")]
+    #[suggestion(code = "", applicability = "maybe-incorrect")]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("arbitrary expressions aren't allowed in patterns")]
+#[diag(ast_lowering_arbitrary_expression_in_pattern)]
 pub(crate) struct ArbitraryExpressionInPattern {
     #[primary_span]
     pub span: Span,
-    #[note("the `expr` fragment specifier forces the metavariable's content to be an expression")]
+    #[note(ast_lowering_pattern_from_macro_note)]
     pub pattern_from_macro_note: bool,
-    #[help("use a named `const`-item or an `if`-guard (`x if x == const {\"{ ... }\"}`) instead")]
-    pub const_block_in_pattern_help: bool,
 }
 
 #[derive(Diagnostic)]
-#[diag("inclusive range with no end")]
+#[diag(ast_lowering_inclusive_range_with_no_end)]
 pub(crate) struct InclusiveRangeWithNoEnd {
     #[primary_span]
     pub span: Span,
@@ -389,7 +368,7 @@ pub(crate) struct InclusiveRangeWithNoEnd {
 
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(
-    "use the right argument notation and remove the return type",
+    ast_lowering_bad_return_type_notation_output_suggestion,
     applicability = "machine-applicable",
     style = "verbose"
 )]
@@ -403,36 +382,26 @@ pub(crate) struct RTNSuggestion {
 
 #[derive(Diagnostic)]
 pub(crate) enum BadReturnTypeNotation {
-    #[diag("argument types not allowed with return type notation")]
+    #[diag(ast_lowering_bad_return_type_notation_inputs)]
     Inputs {
         #[primary_span]
-        #[suggestion(
+        #[suggestion(code = "(..)", applicability = "machine-applicable", style = "verbose")]
-            "remove the input types",
-            code = "(..)",
-            applicability = "machine-applicable",
-            style = "verbose"
-        )]
         span: Span,
     },
-    #[diag("return type not allowed with return type notation")]
+    #[diag(ast_lowering_bad_return_type_notation_output)]
     Output {
         #[primary_span]
         span: Span,
         #[subdiagnostic]
         suggestion: RTNSuggestion,
     },
-    #[diag("return type notation arguments must be elided with `..`")]
+    #[diag(ast_lowering_bad_return_type_notation_needs_dots)]
     NeedsDots {
         #[primary_span]
-        #[suggestion(
+        #[suggestion(code = "(..)", applicability = "machine-applicable", style = "verbose")]
-            "use the correct syntax by adding `..` to the arguments",
-            code = "(..)",
-            applicability = "machine-applicable",
-            style = "verbose"
-        )]
         span: Span,
     },
-    #[diag("return type notation not allowed in this position yet")]
+    #[diag(ast_lowering_bad_return_type_notation_position)]
     Position {
         #[primary_span]
         span: Span,
@@ -440,14 +409,14 @@ pub(crate) enum BadReturnTypeNotation {
 }
 
 #[derive(Diagnostic)]
-#[diag("defaults for generic parameters are not allowed in `for<...>` binders")]
+#[diag(ast_lowering_generic_param_default_in_binder)]
 pub(crate) struct GenericParamDefaultInBinder {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`async` bound modifier only allowed on trait, not `{$descr}`")]
+#[diag(ast_lowering_async_bound_not_on_trait)]
 pub(crate) struct AsyncBoundNotOnTrait {
     #[primary_span]
     pub span: Span,
@@ -455,37 +424,30 @@ pub(crate) struct AsyncBoundNotOnTrait {
 }
 
 #[derive(Diagnostic)]
-#[diag("`async` bound modifier only allowed on `Fn`/`FnMut`/`FnOnce` traits")]
+#[diag(ast_lowering_async_bound_only_for_fn_traits)]
 pub(crate) struct AsyncBoundOnlyForFnTraits {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`use<...>` precise capturing syntax not allowed in argument-position `impl Trait`")]
+#[diag(ast_lowering_no_precise_captures_on_apit)]
 pub(crate) struct NoPreciseCapturesOnApit {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag("`yield` can only be used in `#[coroutine]` closures, or `gen` blocks")]
+#[diag(ast_lowering_yield_in_closure)]
 pub(crate) struct YieldInClosure {
     #[primary_span]
     pub span: Span,
-    #[suggestion(
+    #[suggestion(code = "#[coroutine] ", applicability = "maybe-incorrect", style = "verbose")]
-        "use `#[coroutine]` to make this closure a coroutine",
-        code = "#[coroutine] ",
-        applicability = "maybe-incorrect",
-        style = "verbose"
-    )]
     pub suggestion: Option<Span>,
 }
 
 #[derive(Diagnostic)]
-#[diag(
+#[diag(ast_lowering_invalid_legacy_const_generic_arg)]
-    "invalid argument to a legacy const generic: cannot have const blocks, closures, async blocks or items"
-)]
 pub(crate) struct InvalidLegacyConstGenericArg {
     #[primary_span]
     pub span: Span,
@@ -495,7 +457,7 @@ pub(crate) struct InvalidLegacyConstGenericArg {
 
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(
-    "try using a const generic argument instead",
+    ast_lowering_invalid_legacy_const_generic_arg_suggestion,
     applicability = "maybe-incorrect"
 )]
 pub(crate) struct UseConstGenericArg {
@@ -508,22 +470,8 @@ pub(crate) struct UseConstGenericArg {
 }
 
 #[derive(Diagnostic)]
-#[diag("unions cannot have default field values")]
+#[diag(ast_lowering_union_default_field_values)]
 pub(crate) struct UnionWithDefault {
     #[primary_span]
     pub span: Span,
 }
-
-#[derive(Diagnostic)]
-#[diag("failed to resolve delegation callee")]
-pub(crate) struct UnresolvedDelegationCallee {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag("encountered a cycle during delegation signature resolution")]
-pub(crate) struct CycleInDelegationSignatureResolution {
-    #[primary_span]
-    pub span: Span,
-}

compiler/rustc_ast_lowering/src/expr.rs

@@ -1,11 +1,9 @@
-use std::mem;
 use std::ops::ControlFlow;
 use std::sync::Arc;
 
 use rustc_ast::*;
 use rustc_ast_pretty::pprust::expr_to_string;
 use rustc_data_structures::stack::ensure_sufficient_stack;
-use rustc_errors::msg;
 use rustc_hir as hir;
 use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, Res};
@@ -29,7 +27,7 @@ use super::{
     GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt,
 };
 use crate::errors::{InvalidLegacyConstGenericArg, UseConstGenericArg, YieldInClosure};
-use crate::{AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, TryBlockScope};
+use crate::{AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, fluent_generated};
 
 struct WillCreateDefIdsVisitor {}
 
@@ -113,8 +111,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
                 ExprKind::Call(f, args) => {
-                    if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f, self.tcx)
+                    if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) {
-                    {
                         self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args)
                     } else {
                         let f = self.lower_expr(f);
@@ -157,14 +154,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::Cast(expr, ty) => {
                     let expr = self.lower_expr(expr);
-                    let ty = self
+                    let ty =
-                        .lower_ty_alloc(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
+                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
                     hir::ExprKind::Cast(expr, ty)
                 }
                 ExprKind::Type(expr, ty) => {
                     let expr = self.lower_expr(expr);
-                    let ty = self
+                    let ty =
-                        .lower_ty_alloc(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
+                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
                     hir::ExprKind::Type(expr, ty)
                 }
                 ExprKind::AddrOf(k, m, ohs) => {
@@ -202,9 +199,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         )
                     })
                 }
-                ExprKind::TryBlock(body, opt_ty) => {
+                ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
-                    self.lower_expr_try_block(body, opt_ty.as_deref())
-                }
                 ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
                     self.lower_expr(expr),
                     self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
@@ -334,7 +329,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::FormatArgs(fmt) => self.lower_format_args(e.span, fmt),
                 ExprKind::OffsetOf(container, fields) => hir::ExprKind::OffsetOf(
-                    self.lower_ty_alloc(
+                    self.lower_ty(
                         container,
                         ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
                     ),
@@ -370,10 +365,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     *kind,
                     self.lower_expr(expr),
                     ty.as_ref().map(|ty| {
-                        self.lower_ty_alloc(
+                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
-                            ty,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Cast),
-                        )
                     }),
                 ),
 
@@ -492,11 +484,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     arg
                 };
 
-                let anon_const = AnonConst {
+                let anon_const = AnonConst { id: node_id, value: const_value };
-                    id: node_id,
-                    value: const_value,
-                    mgca_disambiguation: MgcaDisambiguation::AnonConst,
-                };
                 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
             } else {
                 real_args.push(arg);
@@ -574,14 +562,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// Desugar `try { <stmts>; <expr> }` into `{ <stmts>; ::std::ops::Try::from_output(<expr>) }`,
     /// `try { <stmts>; }` into `{ <stmts>; ::std::ops::Try::from_output(()) }`
     /// and save the block id to use it as a break target for desugaring of the `?` operator.
-    fn lower_expr_try_block(&mut self, body: &Block, opt_ty: Option<&Ty>) -> hir::ExprKind<'hir> {
+    fn lower_expr_try_block(&mut self, body: &Block) -> hir::ExprKind<'hir> {
         let body_hir_id = self.lower_node_id(body.id);
-        let new_scope = if opt_ty.is_some() {
+        self.with_catch_scope(body_hir_id, |this| {
-            TryBlockScope::Heterogeneous(body_hir_id)
-        } else {
-            TryBlockScope::Homogeneous(body_hir_id)
-        };
-        let whole_block = self.with_try_block_scope(new_scope, |this| {
             let mut block = this.lower_block_noalloc(body_hir_id, body, true);
 
             // Final expression of the block (if present) or `()` with span at the end of block
@@ -615,16 +598,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 ok_wrapped_span,
             ));
 
-            this.arena.alloc(block)
+            hir::ExprKind::Block(this.arena.alloc(block), None)
-        });
+        })
-
-        if let Some(ty) = opt_ty {
-            let ty = self.lower_ty_alloc(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Path));
-            let block_expr = self.arena.alloc(self.expr_block(whole_block));
-            hir::ExprKind::Type(block_expr, ty)
-        } else {
-            hir::ExprKind::Block(whole_block, None)
-        }
     }
 
     fn wrap_in_try_constructor(
@@ -966,14 +941,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
                 this.arena.alloc(this.expr(gen_future_span, expr_break))
             });
-            self.arm(ready_pat, break_x, span)
+            self.arm(ready_pat, break_x)
         };
 
         // `::std::task::Poll::Pending => {}`
         let pending_arm = {
             let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
             let empty_block = self.expr_block_empty(span);
-            self.arm(pending_pat, empty_block, span)
+            self.arm(pending_pat, empty_block)
         };
 
         let inner_match_stmt = {
@@ -1027,7 +1002,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         });
 
         // mut __awaitee => loop { ... }
-        let awaitee_arm = self.arm(awaitee_pat, loop_expr, span);
+        let awaitee_arm = self.arm(awaitee_pat, loop_expr);
 
         // `match ::std::future::IntoFuture::into_future(<expr>) { ... }`
         let into_future_expr = match await_kind {
@@ -1642,14 +1617,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    fn with_try_block_scope<T>(
+    fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
-        &mut self,
+        let old_scope = self.catch_scope.replace(catch_id);
-        scope: TryBlockScope,
-        f: impl FnOnce(&mut Self) -> T,
-    ) -> T {
-        let old_scope = mem::replace(&mut self.try_block_scope, scope);
         let result = f(self);
-        self.try_block_scope = old_scope;
+        self.catch_scope = old_scope;
         result
     }
 
@@ -1702,7 +1673,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 &self.tcx.sess,
                 sym::yield_expr,
                 span,
-                msg!("yield syntax is experimental"),
+                fluent_generated::ast_lowering_yield,
             )
             .emit();
         }
@@ -1817,7 +1788,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             let break_expr =
                 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
             let pat = self.pat_none(for_span);
-            self.arm(pat, break_expr, for_span)
+            self.arm(pat, break_expr)
         };
 
         // Some(<pat>) => <body>,
@@ -1826,7 +1797,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             let body_block =
                 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
             let body_expr = self.arena.alloc(self.expr_block(body_block));
-            self.arm(some_pat, body_expr, for_span)
+            self.arm(some_pat, body_expr)
         };
 
         // `mut iter`
@@ -1885,7 +1856,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
 
         // `mut iter => { ... }`
-        let iter_arm = self.arm(iter_pat, loop_expr, for_span);
+        let iter_arm = self.arm(iter_pat, loop_expr);
 
         let match_expr = match loop_kind {
             ForLoopKind::For => {
@@ -1930,7 +1901,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir::LangItem::IntoAsyncIterIntoIter,
                     arena_vec![self; head],
                 );
-                let iter_arm = self.arm(async_iter_pat, inner_match_expr, for_span);
+                let iter_arm = self.arm(async_iter_pat, inner_match_expr);
                 self.arena.alloc(self.expr_match(
                     for_span,
                     iter,
@@ -1997,7 +1968,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
             self.lower_attrs(val_expr.hir_id, &attrs, span, Target::Expression);
             let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
-            self.arm(continue_pat, val_expr, try_span)
+            self.arm(continue_pat, val_expr)
         };
 
         // `ControlFlow::Break(residual) =>
@@ -2007,25 +1978,18 @@ impl<'hir> LoweringContext<'_, 'hir> {
             let residual_ident = Ident::with_dummy_span(sym::residual);
             let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
             let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
-
-            let (constructor_item, target_id) = match self.try_block_scope {
-                TryBlockScope::Function => {
-                    (hir::LangItem::TryTraitFromResidual, Err(hir::LoopIdError::OutsideLoopScope))
-                }
-                TryBlockScope::Homogeneous(block_id) => {
-                    (hir::LangItem::ResidualIntoTryType, Ok(block_id))
-                }
-                TryBlockScope::Heterogeneous(block_id) => {
-                    (hir::LangItem::TryTraitFromResidual, Ok(block_id))
-                }
-            };
             let from_residual_expr = self.wrap_in_try_constructor(
-                constructor_item,
+                if self.catch_scope.is_some() {
+                    hir::LangItem::ResidualIntoTryType
+                } else {
+                    hir::LangItem::TryTraitFromResidual
+                },
                 try_span,
                 self.arena.alloc(residual_expr),
                 unstable_span,
             );
-            let ret_expr = if target_id.is_ok() {
+            let ret_expr = if let Some(catch_id) = self.catch_scope {
+                let target_id = Ok(catch_id);
                 self.arena.alloc(self.expr(
                     try_span,
                     hir::ExprKind::Break(
@@ -2040,7 +2004,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             self.lower_attrs(ret_expr.hir_id, &attrs, span, Target::Expression);
 
             let break_pat = self.pat_cf_break(try_span, residual_local);
-            self.arm(break_pat, ret_expr, try_span)
+            self.arm(break_pat, ret_expr)
         };
 
         hir::ExprKind::Match(
@@ -2080,14 +2044,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
             yeeted_span,
         );
 
-        match self.try_block_scope {
+        if let Some(catch_id) = self.catch_scope {
-            TryBlockScope::Homogeneous(block_id) | TryBlockScope::Heterogeneous(block_id) => {
+            let target_id = Ok(catch_id);
-                hir::ExprKind::Break(
+            hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
-                    hir::Destination { label: None, target_id: Ok(block_id) },
+        } else {
-                    Some(from_yeet_expr),
+            self.checked_return(Some(from_yeet_expr))
-                )
-            }
-            TryBlockScope::Function => self.checked_return(Some(from_yeet_expr)),
         }
     }
 
@@ -2368,13 +2329,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &mut self,
         pat: &'hir hir::Pat<'hir>,
         expr: &'hir hir::Expr<'hir>,
-        span: Span,
     ) -> hir::Arm<'hir> {
         hir::Arm {
             hir_id: self.next_id(),
             pat,
             guard: None,
-            span: self.lower_span(span),
+            span: self.lower_span(expr.span),
             body: expr,
         }
     }

compiler/rustc_ast_lowering/src/index.rs

@@ -281,13 +281,6 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    fn visit_const_arg_expr_field(&mut self, field: &'hir ConstArgExprField<'hir>) {
-        self.insert(field.span, field.hir_id, Node::ConstArgExprField(field));
-        self.with_parent(field.hir_id, |this| {
-            intravisit::walk_const_arg_expr_field(this, field);
-        })
-    }
-
     fn visit_stmt(&mut self, stmt: &'hir Stmt<'hir>) {
         self.insert(stmt.span, stmt.hir_id, Node::Stmt(stmt));
 
@@ -312,7 +305,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
 
     fn visit_const_arg(&mut self, const_arg: &'hir ConstArg<'hir, AmbigArg>) {
         self.insert(
-            const_arg.as_unambig_ct().span,
+            const_arg.as_unambig_ct().span(),
             const_arg.hir_id,
             Node::ConstArg(const_arg.as_unambig_ct()),
         );

compiler/rustc_ast_lowering/src/item.rs

@@ -2,7 +2,7 @@ use rustc_abi::ExternAbi;
 use rustc_ast::visit::AssocCtxt;
 use rustc_ast::*;
 use rustc_errors::{E0570, ErrorGuaranteed, struct_span_code_err};
-use rustc_hir::attrs::{AttributeKind, EiiImplResolution};
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, PerNS, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, LocalDefId};
 use rustc_hir::{
@@ -11,7 +11,6 @@ use rustc_hir::{
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::span_bug;
 use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
-use rustc_span::def_id::DefId;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, kw, sym};
 use smallvec::{SmallVec, smallvec};
@@ -134,108 +133,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    fn lower_eii_decl(
-        &mut self,
-        id: NodeId,
-        name: Ident,
-        EiiDecl { foreign_item, impl_unsafe }: &EiiDecl,
-    ) -> Option<hir::attrs::EiiDecl> {
-        self.lower_path_simple_eii(id, foreign_item).map(|did| hir::attrs::EiiDecl {
-            foreign_item: did,
-            impl_unsafe: *impl_unsafe,
-            name,
-        })
-    }
-
-    fn lower_eii_impl(
-        &mut self,
-        EiiImpl {
-            node_id,
-            eii_macro_path,
-            impl_safety,
-            span,
-            inner_span,
-            is_default,
-            known_eii_macro_resolution,
-        }: &EiiImpl,
-    ) -> hir::attrs::EiiImpl {
-        let resolution = if let Some(target) = known_eii_macro_resolution
-            && let Some(decl) = self.lower_eii_decl(
-                *node_id,
-                // the expect is ok here since we always generate this path in the eii macro.
-                eii_macro_path.segments.last().expect("at least one segment").ident,
-                target,
-            ) {
-            EiiImplResolution::Known(decl)
-        } else if let Some(macro_did) = self.lower_path_simple_eii(*node_id, eii_macro_path) {
-            EiiImplResolution::Macro(macro_did)
-        } else {
-            EiiImplResolution::Error(
-                self.dcx().span_delayed_bug(*span, "eii never resolved without errors given"),
-            )
-        };
-
-        hir::attrs::EiiImpl {
-            span: self.lower_span(*span),
-            inner_span: self.lower_span(*inner_span),
-            impl_marked_unsafe: self.lower_safety(*impl_safety, hir::Safety::Safe).is_unsafe(),
-            is_default: *is_default,
-            resolution,
-        }
-    }
-
-    fn generate_extra_attrs_for_item_kind(
-        &mut self,
-        id: NodeId,
-        i: &ItemKind,
-    ) -> Vec<hir::Attribute> {
-        match i {
-            ItemKind::Fn(box Fn { eii_impls, .. }) if eii_impls.is_empty() => Vec::new(),
-            ItemKind::Fn(box Fn { eii_impls, .. }) => {
-                vec![hir::Attribute::Parsed(AttributeKind::EiiImpls(
-                    eii_impls.iter().map(|i| self.lower_eii_impl(i)).collect(),
-                ))]
-            }
-            ItemKind::MacroDef(name, MacroDef { eii_declaration: Some(target), .. }) => self
-                .lower_eii_decl(id, *name, target)
-                .map(|decl| vec![hir::Attribute::Parsed(AttributeKind::EiiDeclaration(decl))])
-                .unwrap_or_default(),
-
-            ItemKind::ExternCrate(..)
-            | ItemKind::Use(..)
-            | ItemKind::Static(..)
-            | ItemKind::Const(..)
-            | ItemKind::ConstBlock(..)
-            | ItemKind::Mod(..)
-            | ItemKind::ForeignMod(..)
-            | ItemKind::GlobalAsm(..)
-            | ItemKind::TyAlias(..)
-            | ItemKind::Enum(..)
-            | ItemKind::Struct(..)
-            | ItemKind::Union(..)
-            | ItemKind::Trait(..)
-            | ItemKind::TraitAlias(..)
-            | ItemKind::Impl(..)
-            | ItemKind::MacCall(..)
-            | ItemKind::MacroDef(..)
-            | ItemKind::Delegation(..)
-            | ItemKind::DelegationMac(..) => Vec::new(),
-        }
-    }
-
     fn lower_item(&mut self, i: &Item) -> &'hir hir::Item<'hir> {
         let vis_span = self.lower_span(i.vis.span);
         let hir_id = hir::HirId::make_owner(self.current_hir_id_owner.def_id);
-
+        let attrs = self.lower_attrs(hir_id, &i.attrs, i.span, Target::from_ast_item(i));
-        let extra_hir_attributes = self.generate_extra_attrs_for_item_kind(i.id, &i.kind);
-        let attrs = self.lower_attrs_with_extra(
-            hir_id,
-            &i.attrs,
-            i.span,
-            Target::from_ast_item(i),
-            &extra_hir_attributes,
-        );
-
         let kind = self.lower_item_kind(i.span, i.id, hir_id, attrs, vis_span, &i.kind);
         let item = hir::Item {
             owner_id: hir_id.expect_owner(),
@@ -243,7 +144,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
             vis_span,
             span: self.lower_span(i.span),
             has_delayed_lints: !self.delayed_lints.is_empty(),
-            eii: find_attr!(attrs, AttributeKind::EiiImpls(..) | AttributeKind::EiiDeclaration(..)),
         };
         self.arena.alloc(item)
     }
@@ -277,19 +177,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 define_opaque,
             }) => {
                 let ident = self.lower_ident(*ident);
-                let ty = self
+                let ty =
-                    .lower_ty_alloc(ty, ImplTraitContext::Disallowed(ImplTraitPosition::StaticTy));
+                    self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::StaticTy));
                 let body_id = self.lower_const_body(span, e.as_deref());
                 self.lower_define_opaque(hir_id, define_opaque);
                 hir::ItemKind::Static(*m, ident, ty, body_id)
             }
-            ItemKind::Const(box ConstItem {
+            ItemKind::Const(box ast::ConstItem {
-                defaultness: _,
+                ident, generics, ty, rhs, define_opaque, ..
-                ident,
-                generics,
-                ty,
-                rhs_kind,
-                define_opaque,
             }) => {
                 let ident = self.lower_ident(*ident);
                 let (generics, (ty, rhs)) = self.lower_generics(
@@ -297,30 +192,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     id,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
-                        let ty = this.lower_ty_alloc(
+                        let ty = this
-                            ty,
+                            .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy));
-                            ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy),
+                        let rhs = this.lower_const_item_rhs(attrs, rhs.as_ref(), span);
-                        );
-                        let rhs = this.lower_const_item_rhs(rhs_kind, span);
                         (ty, rhs)
                     },
                 );
                 self.lower_define_opaque(hir_id, &define_opaque);
                 hir::ItemKind::Const(ident, generics, ty, rhs)
             }
-            ItemKind::ConstBlock(ConstBlockItem { span, id, block }) => hir::ItemKind::Const(
-                self.lower_ident(ConstBlockItem::IDENT),
-                hir::Generics::empty(),
-                self.arena.alloc(self.ty_tup(DUMMY_SP, &[])),
-                hir::ConstItemRhs::Body({
-                    let body = hir::Expr {
-                        hir_id: self.lower_node_id(*id),
-                        kind: hir::ExprKind::Block(self.lower_block(block, false), None),
-                        span: self.lower_span(*span),
-                    };
-                    self.record_body(&[], body)
-                }),
-            ),
             ItemKind::Fn(box Fn {
                 sig: FnSig { decl, header, span: fn_sig_span },
                 ident,
@@ -412,7 +292,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             );
                             this.arena.alloc(this.ty(span, hir::TyKind::Err(guar)))
                         }
-                        Some(ty) => this.lower_ty_alloc(
+                        Some(ty) => this.lower_ty(
                             ty,
                             ImplTraitContext::OpaqueTy {
                                 origin: hir::OpaqueTyOrigin::TyAlias {
@@ -486,7 +366,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             .as_deref()
                             .map(|of_trait| this.lower_trait_impl_header(of_trait));
 
-                        let lowered_ty = this.lower_ty_alloc(
+                        let lowered_ty = this.lower_ty(
                             ty,
                             ImplTraitContext::Disallowed(ImplTraitPosition::ImplSelf),
                         );
@@ -555,7 +435,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 );
                 hir::ItemKind::TraitAlias(constness, ident, generics, bounds)
             }
-            ItemKind::MacroDef(ident, MacroDef { body, macro_rules, eii_declaration: _ }) => {
+            ItemKind::MacroDef(ident, MacroDef { body, macro_rules }) => {
                 let ident = self.lower_ident(*ident);
                 let body = Box::new(self.lower_delim_args(body));
                 let def_id = self.local_def_id(id);
@@ -566,15 +446,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         def_kind.descr(def_id.to_def_id())
                     );
                 };
-                let macro_def = self.arena.alloc(ast::MacroDef {
+                let macro_def = self.arena.alloc(ast::MacroDef { body, macro_rules: *macro_rules });
-                    body,
-                    macro_rules: *macro_rules,
-                    eii_declaration: None,
-                });
                 hir::ItemKind::Macro(ident, macro_def, macro_kinds)
             }
             ItemKind::Delegation(box delegation) => {
-                let delegation_results = self.lower_delegation(delegation, id);
+                let delegation_results = self.lower_delegation(delegation, id, false);
                 hir::ItemKind::Fn {
                     sig: delegation_results.sig,
                     ident: delegation_results.ident,
@@ -589,16 +465,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    fn lower_path_simple_eii(&mut self, id: NodeId, path: &Path) -> Option<DefId> {
-        let res = self.resolver.get_partial_res(id)?;
-        let Some(did) = res.expect_full_res().opt_def_id() else {
-            self.dcx().span_delayed_bug(path.span, "should have errored in resolve");
-            return None;
-        };
-
-        Some(did)
-    }
-
     #[instrument(level = "debug", skip(self))]
     fn lower_use_tree(
         &mut self,
@@ -707,10 +573,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             vis_span,
                             span: this.lower_span(use_tree.span),
                             has_delayed_lints: !this.delayed_lints.is_empty(),
-                            eii: find_attr!(
-                                attrs,
-                                AttributeKind::EiiImpls(..) | AttributeKind::EiiDeclaration(..)
-                            ),
                         };
                         hir::OwnerNode::Item(this.arena.alloc(item))
                     });
@@ -791,8 +653,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 safety,
                 define_opaque,
             }) => {
-                let ty = self
+                let ty =
-                    .lower_ty_alloc(ty, ImplTraitContext::Disallowed(ImplTraitPosition::StaticTy));
+                    self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::StaticTy));
                 let safety = self.lower_safety(*safety, hir::Safety::Unsafe);
                 if define_opaque.is_some() {
                     self.dcx().span_err(i.span, "foreign statics cannot define opaque types");
@@ -827,10 +689,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir_id,
             def_id: self.local_def_id(v.id),
             data: self.lower_variant_data(hir_id, item_kind, &v.data),
-            disr_expr: v
+            disr_expr: v.disr_expr.as_ref().map(|e| self.lower_anon_const_to_anon_const(e)),
-                .disr_expr
-                .as_ref()
-                .map(|e| self.lower_anon_const_to_anon_const(e, e.value.span)),
             ident: self.lower_ident(v.ident),
             span: self.lower_span(v.span),
         }
@@ -906,8 +765,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &mut self,
         (index, f): (usize, &FieldDef),
     ) -> hir::FieldDef<'hir> {
-        let ty =
+        let ty = self.lower_ty(&f.ty, ImplTraitContext::Disallowed(ImplTraitPosition::FieldTy));
-            self.lower_ty_alloc(&f.ty, ImplTraitContext::Disallowed(ImplTraitPosition::FieldTy));
         let hir_id = self.lower_node_id(f.id);
         self.lower_attrs(hir_id, &f.attrs, f.span, Target::Field);
         hir::FieldDef {
@@ -920,10 +778,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 None => Ident::new(sym::integer(index), self.lower_span(f.span)),
             },
             vis_span: self.lower_span(f.vis.span),
-            default: f
+            default: f.default.as_ref().map(|v| self.lower_anon_const_to_anon_const(v)),
-                .default
-                .as_ref()
-                .map(|v| self.lower_anon_const_to_anon_const(v, v.value.span)),
             ty,
             safety: self.lower_safety(f.safety, hir::Safety::Safe),
         }
@@ -939,36 +794,26 @@ impl<'hir> LoweringContext<'_, 'hir> {
         );
         let trait_item_def_id = hir_id.expect_owner();
 
-        let (ident, generics, kind, has_value) = match &i.kind {
+        let (ident, generics, kind, has_default) = match &i.kind {
             AssocItemKind::Const(box ConstItem {
-                ident,
+                ident, generics, ty, rhs, define_opaque, ..
-                generics,
-                ty,
-                rhs_kind,
-                define_opaque,
-                ..
             }) => {
                 let (generics, kind) = self.lower_generics(
                     generics,
                     i.id,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
-                        let ty = this.lower_ty_alloc(
+                        let ty = this
-                            ty,
+                            .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy));
-                            ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy),
+                        let rhs = rhs
-                        );
+                            .as_ref()
-                        // Trait associated consts don't need an expression/body.
+                            .map(|rhs| this.lower_const_item_rhs(attrs, Some(rhs), i.span));
-                        let rhs = if rhs_kind.has_expr() {
+                        hir::TraitItemKind::Const(ty, rhs)
-                            Some(this.lower_const_item_rhs(rhs_kind, i.span))
-                        } else {
-                            None
-                        };
-                        hir::TraitItemKind::Const(ty, rhs, rhs_kind.is_type_const().into())
                     },
                 );
 
                 if define_opaque.is_some() {
-                    if rhs_kind.has_expr() {
+                    if rhs.is_some() {
                         self.lower_define_opaque(hir_id, &define_opaque);
                     } else {
                         self.dcx().span_err(
@@ -978,7 +823,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     }
                 }
 
-                (*ident, generics, kind, rhs_kind.has_expr())
+                (*ident, generics, kind, rhs.is_some())
             }
             AssocItemKind::Fn(box Fn {
                 sig, ident, generics, body: None, define_opaque, ..
@@ -1058,7 +903,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
                         let ty = ty.as_ref().map(|x| {
-                            this.lower_ty_alloc(
+                            this.lower_ty(
                                 x,
                                 ImplTraitContext::Disallowed(ImplTraitPosition::AssocTy),
                             )
@@ -1076,7 +921,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 (*ident, generics, kind, ty.is_some())
             }
             AssocItemKind::Delegation(box delegation) => {
-                let delegation_results = self.lower_delegation(delegation, i.id);
+                let delegation_results = self.lower_delegation(delegation, i.id, false);
                 let item_kind = hir::TraitItemKind::Fn(
                     delegation_results.sig,
                     hir::TraitFn::Provided(delegation_results.body_id),
@@ -1088,17 +933,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
         };
 
-        let (defaultness, _) = self.lower_defaultness(i.kind.defaultness(), has_value, || {
-            hir::Defaultness::Default { has_value }
-        });
-
         let item = hir::TraitItem {
             owner_id: trait_item_def_id,
             ident: self.lower_ident(ident),
             generics,
             kind,
             span: self.lower_span(i.span),
-            defaultness,
+            defaultness: hir::Defaultness::Default { has_value: has_default },
             has_delayed_lints: !self.delayed_lints.is_empty(),
         };
         self.arena.alloc(item)
@@ -1126,8 +967,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         // `defaultness.has_value()` is never called for an `impl`, always `true` in order
         // to not cause an assertion failure inside the `lower_defaultness` function.
         let has_val = true;
-        let (defaultness, defaultness_span) =
+        let (defaultness, defaultness_span) = self.lower_defaultness(defaultness, has_val);
-            self.lower_defaultness(defaultness, has_val, || hir::Defaultness::Final);
         let modifiers = TraitBoundModifiers {
             constness: BoundConstness::Never,
             asyncness: BoundAsyncness::Normal,
@@ -1156,8 +996,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     ) -> &'hir hir::ImplItem<'hir> {
         // Since `default impl` is not yet implemented, this is always true in impls.
         let has_value = true;
-        let (defaultness, _) =
+        let (defaultness, _) = self.lower_defaultness(i.kind.defaultness(), has_value);
-            self.lower_defaultness(i.kind.defaultness(), has_value, || hir::Defaultness::Final);
         let hir_id = hir::HirId::make_owner(self.current_hir_id_owner.def_id);
         let attrs = self.lower_attrs(
             hir_id,
@@ -1168,12 +1007,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         let (ident, (generics, kind)) = match &i.kind {
             AssocItemKind::Const(box ConstItem {
-                ident,
+                ident, generics, ty, rhs, define_opaque, ..
-                generics,
-                ty,
-                rhs_kind,
-                define_opaque,
-                ..
             }) => (
                 *ident,
                 self.lower_generics(
@@ -1181,12 +1015,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     i.id,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
-                        let ty = this.lower_ty_alloc(
+                        let ty = this
-                            ty,
+                            .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy));
-                            ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy),
-                        );
                         this.lower_define_opaque(hir_id, &define_opaque);
-                        let rhs = this.lower_const_item_rhs(rhs_kind, i.span);
+                        let rhs = this.lower_const_item_rhs(attrs, rhs.as_ref(), i.span);
                         hir::ImplItemKind::Const(ty, rhs)
                     },
                 ),
@@ -1243,7 +1075,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                                 hir::ImplItemKind::Type(ty)
                             }
                             Some(ty) => {
-                                let ty = this.lower_ty_alloc(
+                                let ty = this.lower_ty(
                                     ty,
                                     ImplTraitContext::OpaqueTy {
                                         origin: hir::OpaqueTyOrigin::TyAlias {
@@ -1259,7 +1091,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 )
             }
             AssocItemKind::Delegation(box delegation) => {
-                let delegation_results = self.lower_delegation(delegation, i.id);
+                let delegation_results = self.lower_delegation(delegation, i.id, is_in_trait_impl);
                 (
                     delegation.ident,
                     (
@@ -1310,14 +1142,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &self,
         d: Defaultness,
         has_value: bool,
-        implicit: impl FnOnce() -> hir::Defaultness,
     ) -> (hir::Defaultness, Option<Span>) {
         match d {
-            Defaultness::Implicit => (implicit(), None),
             Defaultness::Default(sp) => {
                 (hir::Defaultness::Default { has_value }, Some(self.lower_span(sp)))
             }
-            Defaultness::Final(sp) => (hir::Defaultness::Final, Some(self.lower_span(sp))),
+            Defaultness::Final => {
+                assert!(has_value);
+                (hir::Defaultness::Final, None)
+            }
         }
     }
 
@@ -1415,7 +1248,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             // create a fake body so that the entire rest of the compiler doesn't have to deal with
             // this as a special case.
             return self.lower_fn_body(decl, contract, |this| {
-                if find_attr!(attrs, AttributeKind::RustcIntrinsic)
+                if attrs.iter().any(|a| a.has_name(sym::rustc_intrinsic))
                     || this.tcx.is_sdylib_interface_build()
                 {
                     let span = this.lower_span(span);
@@ -1978,7 +1811,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         bound_generic_params,
                         hir::GenericParamSource::Binder,
                     ),
-                    bounded_ty: self.lower_ty_alloc(
+                    bounded_ty: self.lower_ty(
                         bounded_ty,
                         ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
                     ),
@@ -2007,14 +1840,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
             WherePredicateKind::EqPredicate(WhereEqPredicate { lhs_ty, rhs_ty }) => {
                 hir::WherePredicateKind::EqPredicate(hir::WhereEqPredicate {
-                    lhs_ty: self.lower_ty_alloc(
+                    lhs_ty: self
-                        lhs_ty,
+                        .lower_ty(lhs_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Bound)),
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
+                    rhs_ty: self
-                    ),
+                        .lower_ty(rhs_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Bound)),
-                    rhs_ty: self.lower_ty_alloc(
-                        rhs_ty,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
-                    ),
                 })
             }
         });

compiler/rustc_ast_lowering/src/lib.rs

@@ -35,7 +35,6 @@
 #![feature(if_let_guard)]
 // tidy-alphabetical-end
 
-use std::mem;
 use std::sync::Arc;
 
 use rustc_ast::node_id::NodeMap;
@@ -47,14 +46,13 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::spawn;
 use rustc_data_structures::tagged_ptr::TaggedRef;
 use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle};
-use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatorState};
-use rustc_hir::lints::{AttributeLint, DelayedLint};
+use rustc_hir::lints::DelayedLint;
 use rustc_hir::{
     self as hir, AngleBrackets, ConstArg, GenericArg, HirId, ItemLocalMap, LifetimeSource,
-    LifetimeSyntax, ParamName, Target, TraitCandidate, find_attr,
+    LifetimeSyntax, ParamName, Target, TraitCandidate,
 };
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_macros::extension;
@@ -88,6 +86,8 @@ mod pat;
 mod path;
 pub mod stability;
 
+rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
+
 struct LoweringContext<'a, 'hir> {
     tcx: TyCtxt<'hir>,
     resolver: &'a mut ResolverAstLowering,
@@ -117,7 +117,7 @@ struct LoweringContext<'a, 'hir> {
     /// outside of an `async fn`.
     current_item: Option<Span>,
 
-    try_block_scope: TryBlockScope,
+    catch_scope: Option<HirId>,
     loop_scope: Option<HirId>,
     is_in_loop_condition: bool,
     is_in_dyn_type: bool,
@@ -173,7 +173,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             trait_map: Default::default(),
 
             // Lowering state.
-            try_block_scope: TryBlockScope::Function,
+            catch_scope: None,
             loop_scope: None,
             is_in_loop_condition: false,
             is_in_dyn_type: false,
@@ -235,32 +235,29 @@ impl SpanLowerer {
 
 #[extension(trait ResolverAstLoweringExt)]
 impl ResolverAstLowering {
-    fn legacy_const_generic_args(&self, expr: &Expr, tcx: TyCtxt<'_>) -> Option<Vec<usize>> {
+    fn legacy_const_generic_args(&self, expr: &Expr) -> Option<Vec<usize>> {
-        let ExprKind::Path(None, path) = &expr.kind else {
+        if let ExprKind::Path(None, path) = &expr.kind {
-            return None;
+            // Don't perform legacy const generics rewriting if the path already
-        };
+            // has generic arguments.
+            if path.segments.last().unwrap().args.is_some() {
+                return None;
+            }
 
-        // Don't perform legacy const generics rewriting if the path already
+            if let Res::Def(DefKind::Fn, def_id) = self.partial_res_map.get(&expr.id)?.full_res()? {
-        // has generic arguments.
+                // We only support cross-crate argument rewriting. Uses
-        if path.segments.last().unwrap().args.is_some() {
+                // within the same crate should be updated to use the new
-            return None;
+                // const generics style.
+                if def_id.is_local() {
+                    return None;
+                }
+
+                if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
+                    return v.clone();
+                }
+            }
         }
 
-        let def_id = self.partial_res_map.get(&expr.id)?.full_res()?.opt_def_id()?;
+        None
-
-        // We only support cross-crate argument rewriting. Uses
-        // within the same crate should be updated to use the new
-        // const generics style.
-        if def_id.is_local() {
-            return None;
-        }
-
-        find_attr!(
-            // we can use parsed attrs here since for other crates they're already available
-            tcx.get_all_attrs(def_id),
-            AttributeKind::RustcLegacyConstGenerics{fn_indexes,..} => fn_indexes
-        )
-        .map(|fn_indexes| fn_indexes.iter().map(|(num, _)| *num).collect())
     }
 
     fn get_partial_res(&self, id: NodeId) -> Option<PartialRes> {
@@ -419,18 +416,6 @@ enum AstOwner<'a> {
     ForeignItem(&'a ast::ForeignItem),
 }
 
-#[derive(Copy, Clone, Debug)]
-enum TryBlockScope {
-    /// There isn't a `try` block, so a `?` will use `return`.
-    Function,
-    /// We're inside a `try { … }` block, so a `?` will block-break
-    /// from that block using a type depending only on the argument.
-    Homogeneous(HirId),
-    /// We're inside a `try as _ { … }` block, so a `?` will block-break
-    /// from that block using the type specified.
-    Heterogeneous(HirId),
-}
-
 fn index_crate<'a>(
     node_id_to_def_id: &NodeMap<LocalDefId>,
     krate: &'a Crate,
@@ -878,7 +863,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                 (hir::ParamName::Fresh, hir::LifetimeParamKind::Elided(kind))
             }
-            LifetimeRes::Static { .. } | LifetimeRes::Error(..) => return None,
+            LifetimeRes::Static { .. } | LifetimeRes::Error => return None,
             res => panic!(
                 "Unexpected lifetime resolution {:?} for {:?} at {:?}",
                 res, ident, ident.span
@@ -951,10 +936,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
         let old_contract = self.contract_ensures.take();
 
-        let try_block_scope = mem::replace(&mut self.try_block_scope, TryBlockScope::Function);
+        let catch_scope = self.catch_scope.take();
         let loop_scope = self.loop_scope.take();
         let ret = f(self);
-        self.try_block_scope = try_block_scope;
+        self.catch_scope = catch_scope;
         self.loop_scope = loop_scope;
 
         self.contract_ensures = old_contract;
@@ -973,23 +958,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         target_span: Span,
         target: Target,
     ) -> &'hir [hir::Attribute] {
-        self.lower_attrs_with_extra(id, attrs, target_span, target, &[])
+        if attrs.is_empty() {
-    }
-
-    fn lower_attrs_with_extra(
-        &mut self,
-        id: HirId,
-        attrs: &[Attribute],
-        target_span: Span,
-        target: Target,
-        extra_hir_attributes: &[hir::Attribute],
-    ) -> &'hir [hir::Attribute] {
-        if attrs.is_empty() && extra_hir_attributes.is_empty() {
             &[]
         } else {
-            let mut lowered_attrs =
+            let lowered_attrs =
                 self.lower_attrs_vec(attrs, self.lower_span(target_span), id, target);
-            lowered_attrs.extend(extra_hir_attributes.iter().cloned());
 
             assert_eq!(id.owner, self.current_hir_id_owner);
             let ret = self.arena.alloc_from_iter(lowered_attrs);
@@ -1020,16 +993,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.attribute_parser.parse_attribute_list(
             attrs,
             target_span,
+            target_hir_id,
             target,
             OmitDoc::Lower,
             |s| l.lower(s),
-            |lint_id, span, kind| {
+            |l| {
-                self.delayed_lints.push(DelayedLint::AttributeParsing(AttributeLint {
+                self.delayed_lints.push(DelayedLint::AttributeParsing(l));
-                    lint_id,
-                    id: target_hir_id,
-                    span,
-                    kind,
-                }));
             },
         )
     }
@@ -1127,8 +1096,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let kind = match &constraint.kind {
             AssocItemConstraintKind::Equality { term } => {
                 let term = match term {
-                    Term::Ty(ty) => self.lower_ty_alloc(ty, itctx).into(),
+                    Term::Ty(ty) => self.lower_ty(ty, itctx).into(),
-                    Term::Const(c) => self.lower_anon_const_to_const_arg_and_alloc(c).into(),
+                    Term::Const(c) => self.lower_anon_const_to_const_arg(c).into(),
                 };
                 hir::AssocItemConstraintKind::Equality { term }
             }
@@ -1237,7 +1206,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             .and_then(|partial_res| partial_res.full_res())
                         {
                             if !res.matches_ns(Namespace::TypeNS)
-                                && path.is_potential_trivial_const_arg()
+                                && path.is_potential_trivial_const_arg(false)
                             {
                                 debug!(
                                     "lower_generic_arg: Lowering type argument as const argument: {:?}",
@@ -1252,17 +1221,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }
                     _ => {}
                 }
-                GenericArg::Type(self.lower_ty_alloc(ty, itctx).try_as_ambig_ty().unwrap())
+                GenericArg::Type(self.lower_ty(ty, itctx).try_as_ambig_ty().unwrap())
+            }
+            ast::GenericArg::Const(ct) => {
+                GenericArg::Const(self.lower_anon_const_to_const_arg(ct).try_as_ambig_ct().unwrap())
             }
-            ast::GenericArg::Const(ct) => GenericArg::Const(
-                self.lower_anon_const_to_const_arg_and_alloc(ct).try_as_ambig_ct().unwrap(),
-            ),
         }
     }
 
     #[instrument(level = "debug", skip(self))]
-    fn lower_ty_alloc(&mut self, t: &Ty, itctx: ImplTraitContext) -> &'hir hir::Ty<'hir> {
+    fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> &'hir hir::Ty<'hir> {
-        self.arena.alloc(self.lower_ty(t, itctx))
+        self.arena.alloc(self.lower_ty_direct(t, itctx))
     }
 
     fn lower_path_ty(
@@ -1326,11 +1295,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.ty(span, hir::TyKind::Tup(tys))
     }
 
-    fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir> {
+    fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir> {
         let kind = match &t.kind {
             TyKind::Infer => hir::TyKind::Infer(()),
             TyKind::Err(guar) => hir::TyKind::Err(*guar),
-            TyKind::Slice(ty) => hir::TyKind::Slice(self.lower_ty_alloc(ty, itctx)),
+            TyKind::Slice(ty) => hir::TyKind::Slice(self.lower_ty(ty, itctx)),
             TyKind::Ptr(mt) => hir::TyKind::Ptr(self.lower_mt(mt, itctx)),
             TyKind::Ref(region, mt) => {
                 let lifetime = self.lower_ty_direct_lifetime(t, *region);
@@ -1364,15 +1333,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 let generic_params = self.lower_lifetime_binder(t.id, &f.generic_params);
                 hir::TyKind::UnsafeBinder(self.arena.alloc(hir::UnsafeBinderTy {
                     generic_params,
-                    inner_ty: self.lower_ty_alloc(&f.inner_ty, itctx),
+                    inner_ty: self.lower_ty(&f.inner_ty, itctx),
                 }))
             }
             TyKind::Never => hir::TyKind::Never,
             TyKind::Tup(tys) => hir::TyKind::Tup(
-                self.arena.alloc_from_iter(tys.iter().map(|ty| self.lower_ty(ty, itctx))),
+                self.arena.alloc_from_iter(tys.iter().map(|ty| self.lower_ty_direct(ty, itctx))),
             ),
             TyKind::Paren(ty) => {
-                return self.lower_ty(ty, itctx);
+                return self.lower_ty_direct(ty, itctx);
             }
             TyKind::Path(qself, path) => {
                 return self.lower_path_ty(t, qself, path, ParamMode::Explicit, itctx);
@@ -1395,7 +1364,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 ))
             }
             TyKind::Array(ty, length) => hir::TyKind::Array(
-                self.lower_ty_alloc(ty, itctx),
+                self.lower_ty(ty, itctx),
                 self.lower_array_length_to_const_arg(length),
             ),
             TyKind::TraitObject(bounds, kind) => {
@@ -1495,7 +1464,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 }
             }
             TyKind::Pat(ty, pat) => {
-                hir::TyKind::Pat(self.lower_ty_alloc(ty, itctx), self.lower_ty_pat(pat, ty.span))
+                hir::TyKind::Pat(self.lower_ty(ty, itctx), self.lower_ty_pat(pat, ty.span))
             }
             TyKind::MacCall(_) => {
                 span_bug!(t.span, "`TyKind::MacCall` should have been expanded by now")
@@ -1695,13 +1664,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     ImplTraitContext::Disallowed(ImplTraitPosition::PointerParam)
                 }
             };
-            self.lower_ty(&param.ty, itctx)
+            self.lower_ty_direct(&param.ty, itctx)
         }));
 
         let output = match coro {
             Some(coro) => {
                 let fn_def_id = self.local_def_id(fn_node_id);
-                self.lower_coroutine_fn_ret_ty(&decl.output, fn_def_id, coro, kind)
+                self.lower_coroutine_fn_ret_ty(&decl.output, fn_def_id, coro, kind, fn_span)
             }
             None => match &decl.output {
                 FnRetTy::Ty(ty) => {
@@ -1734,7 +1703,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             ImplTraitContext::Disallowed(ImplTraitPosition::PointerReturn)
                         }
                     };
-                    hir::FnRetTy::Return(self.lower_ty_alloc(ty, itctx))
+                    hir::FnRetTy::Return(self.lower_ty(ty, itctx))
                 }
                 FnRetTy::Default(span) => hir::FnRetTy::DefaultReturn(self.lower_span(*span)),
             },
@@ -1786,8 +1755,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         fn_def_id: LocalDefId,
         coro: CoroutineKind,
         fn_kind: FnDeclKind,
+        fn_span: Span,
     ) -> hir::FnRetTy<'hir> {
-        let span = self.lower_span(output.span());
+        let span = self.lower_span(fn_span);
 
         let (opaque_ty_node_id, allowed_features) = match coro {
             CoroutineKind::Async { return_impl_trait_id, .. } => (return_impl_trait_id, None),
@@ -1845,7 +1815,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 // Not `OpaqueTyOrigin::AsyncFn`: that's only used for the
                 // `impl Future` opaque type that `async fn` implicitly
                 // generates.
-                self.lower_ty_alloc(ty, itctx)
+                self.lower_ty(ty, itctx)
             }
             FnRetTy::Default(ret_ty_span) => self.arena.alloc(self.ty_tup(*ret_ty_span, &[])),
         };
@@ -1931,29 +1901,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         source: LifetimeSource,
         syntax: LifetimeSyntax,
     ) -> &'hir hir::Lifetime {
-        let res = if let Some(res) = self.resolver.get_lifetime_res(id) {
+        let res = self.resolver.get_lifetime_res(id).unwrap_or(LifetimeRes::Error);
-            match res {
+        let res = match res {
-                LifetimeRes::Param { param, .. } => hir::LifetimeKind::Param(param),
+            LifetimeRes::Param { param, .. } => hir::LifetimeKind::Param(param),
-                LifetimeRes::Fresh { param, .. } => {
+            LifetimeRes::Fresh { param, .. } => {
-                    assert_eq!(ident.name, kw::UnderscoreLifetime);
+                assert_eq!(ident.name, kw::UnderscoreLifetime);
-                    let param = self.local_def_id(param);
+                let param = self.local_def_id(param);
-                    hir::LifetimeKind::Param(param)
+                hir::LifetimeKind::Param(param)
-                }
+            }
-                LifetimeRes::Infer => {
+            LifetimeRes::Infer => {
-                    assert_eq!(ident.name, kw::UnderscoreLifetime);
+                assert_eq!(ident.name, kw::UnderscoreLifetime);
-                    hir::LifetimeKind::Infer
+                hir::LifetimeKind::Infer
-                }
+            }
-                LifetimeRes::Static { .. } => {
+            LifetimeRes::Static { .. } => {
-                    assert!(matches!(ident.name, kw::StaticLifetime | kw::UnderscoreLifetime));
+                assert!(matches!(ident.name, kw::StaticLifetime | kw::UnderscoreLifetime));
-                    hir::LifetimeKind::Static
+                hir::LifetimeKind::Static
-                }
+            }
-                LifetimeRes::Error(guar) => hir::LifetimeKind::Error(guar),
+            LifetimeRes::Error => hir::LifetimeKind::Error,
-                LifetimeRes::ElidedAnchor { .. } => {
+            LifetimeRes::ElidedAnchor { .. } => {
-                    panic!("Unexpected `ElidedAnchar` {:?} at {:?}", ident, ident.span);
+                panic!("Unexpected `ElidedAnchar` {:?} at {:?}", ident, ident.span);
-                }
             }
-        } else {
-            hir::LifetimeKind::Error(self.dcx().span_delayed_bug(ident.span, "unresolved lifetime"))
         };
 
         debug!(?res);
@@ -1991,9 +1958,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let (name, kind) = self.lower_generic_param_kind(param, source);
 
         let hir_id = self.lower_node_id(param.id);
-        let param_attrs = &param.attrs;
+        self.lower_attrs(hir_id, &param.attrs, param.span(), Target::Param);
-        let param_span = param.span();
+        hir::GenericParam {
-        let param = hir::GenericParam {
             hir_id,
             def_id: self.local_def_id(param.id),
             name,
@@ -2002,9 +1968,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             kind,
             colon_span: param.colon_span.map(|s| self.lower_span(s)),
             source,
-        };
+        }
-        self.lower_attrs(hir_id, param_attrs, param_span, Target::from_generic_param(&param));
-        param
     }
 
     fn lower_generic_param_kind(
@@ -2017,13 +1981,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 // AST resolution emitted an error on those parameters, so we lower them using
                 // `ParamName::Error`.
                 let ident = self.lower_ident(param.ident);
-                let param_name = if let Some(LifetimeRes::Error(..)) =
+                let param_name =
-                    self.resolver.get_lifetime_res(param.id)
+                    if let Some(LifetimeRes::Error) = self.resolver.get_lifetime_res(param.id) {
-                {
+                        ParamName::Error(ident)
-                    ParamName::Error(ident)
+                    } else {
-                } else {
+                        ParamName::Plain(ident)
-                    ParamName::Plain(ident)
+                    };
-                };
                 let kind =
                     hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit };
 
@@ -2045,7 +2008,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         }
                     })
                     .map(|def| {
-                        self.lower_ty_alloc(
+                        self.lower_ty(
                             def,
                             ImplTraitContext::Disallowed(ImplTraitPosition::GenericDefault),
                         )
@@ -2056,10 +2019,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 (hir::ParamName::Plain(self.lower_ident(param.ident)), kind)
             }
             GenericParamKind::Const { ty, span: _, default } => {
-                let ty = self.lower_ty_alloc(
+                let ty = self
-                    ty,
+                    .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::GenericDefault));
-                    ImplTraitContext::Disallowed(ImplTraitPosition::GenericDefault),
-                );
 
                 // Not only do we deny const param defaults in binders but we also map them to `None`
                 // since later compiler stages cannot handle them (and shouldn't need to be able to).
@@ -2075,7 +2036,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             false
                         }
                     })
-                    .map(|def| self.lower_anon_const_to_const_arg_and_alloc(def));
+                    .map(|def| self.lower_anon_const_to_const_arg(def));
 
                 (
                     hir::ParamName::Plain(self.lower_ident(param.ident)),
@@ -2209,7 +2170,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext) -> hir::MutTy<'hir> {
-        hir::MutTy { ty: self.lower_ty_alloc(&mt.ty, itctx), mutbl: mt.mutbl }
+        hir::MutTy { ty: self.lower_ty(&mt.ty, itctx), mutbl: mt.mutbl }
     }
 
     #[instrument(level = "debug", skip(self), ret)]
@@ -2294,14 +2255,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // `ExprKind::Paren(ExprKind::Underscore)` and should also be lowered to `GenericArg::Infer`
         match c.value.peel_parens().kind {
             ExprKind::Underscore => {
-                let ct_kind = hir::ConstArgKind::Infer(());
+                let ct_kind = hir::ConstArgKind::Infer(self.lower_span(c.value.span), ());
-                self.arena.alloc(hir::ConstArg {
+                self.arena.alloc(hir::ConstArg { hir_id: self.lower_node_id(c.id), kind: ct_kind })
-                    hir_id: self.lower_node_id(c.id),
-                    kind: ct_kind,
-                    span: self.lower_span(c.value.span),
-                })
             }
-            _ => self.lower_anon_const_to_const_arg_and_alloc(c),
+            _ => self.lower_anon_const_to_const_arg(c),
         }
     }
 
@@ -2318,9 +2275,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     ) -> &'hir hir::ConstArg<'hir> {
         let tcx = self.tcx;
 
-        let is_trivial_path = path.is_potential_trivial_const_arg()
+        let ct_kind = if path
-            && matches!(res, Res::Def(DefKind::ConstParam, _));
+            .is_potential_trivial_const_arg(tcx.features().min_generic_const_args())
-        let ct_kind = if is_trivial_path || tcx.features().min_generic_const_args() {
+            && (tcx.features().min_generic_const_args()
+                || matches!(res, Res::Def(DefKind::ConstParam, _)))
+        {
             let qpath = self.lower_qpath(
                 ty_id,
                 &None,
@@ -2369,242 +2328,45 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             hir::ConstArgKind::Anon(ct)
         };
 
-        self.arena.alloc(hir::ConstArg {
+        self.arena.alloc(hir::ConstArg { hir_id: self.next_id(), kind: ct_kind })
-            hir_id: self.next_id(),
-            kind: ct_kind,
-            span: self.lower_span(span),
-        })
     }
 
     fn lower_const_item_rhs(
         &mut self,
-        rhs_kind: &ConstItemRhsKind,
+        attrs: &[hir::Attribute],
+        rhs: Option<&ConstItemRhs>,
         span: Span,
     ) -> hir::ConstItemRhs<'hir> {
-        match rhs_kind {
+        match rhs {
-            ConstItemRhsKind::Body { rhs: Some(body) } => {
+            Some(ConstItemRhs::TypeConst(anon)) => {
-                hir::ConstItemRhs::Body(self.lower_const_body(span, Some(body)))
+                hir::ConstItemRhs::TypeConst(self.lower_anon_const_to_const_arg(anon))
             }
-            ConstItemRhsKind::Body { rhs: None } => {
+            None if attr::contains_name(attrs, sym::type_const) => {
-                hir::ConstItemRhs::Body(self.lower_const_body(span, None))
-            }
-            ConstItemRhsKind::TypeConst { rhs: Some(anon) } => {
-                hir::ConstItemRhs::TypeConst(self.lower_anon_const_to_const_arg_and_alloc(anon))
-            }
-            ConstItemRhsKind::TypeConst { rhs: None } => {
                 let const_arg = ConstArg {
                     hir_id: self.next_id(),
                     kind: hir::ConstArgKind::Error(
+                        DUMMY_SP,
                         self.dcx().span_delayed_bug(DUMMY_SP, "no block"),
                     ),
-                    span: DUMMY_SP,
                 };
                 hir::ConstItemRhs::TypeConst(self.arena.alloc(const_arg))
             }
-        }
+            Some(ConstItemRhs::Body(body)) => {
-    }
+                hir::ConstItemRhs::Body(self.lower_const_body(span, Some(body)))
-
-    #[instrument(level = "debug", skip(self), ret)]
-    fn lower_expr_to_const_arg_direct(&mut self, expr: &Expr) -> hir::ConstArg<'hir> {
-        let span = self.lower_span(expr.span);
-
-        let overly_complex_const = |this: &mut Self| {
-            let e = this.dcx().struct_span_err(
-                expr.span,
-                "complex const arguments must be placed inside of a `const` block",
-            );
-
-            ConstArg { hir_id: this.next_id(), kind: hir::ConstArgKind::Error(e.emit()), span }
-        };
-
-        match &expr.kind {
-            ExprKind::Call(func, args) if let ExprKind::Path(qself, path) = &func.kind => {
-                let qpath = self.lower_qpath(
-                    func.id,
-                    qself,
-                    path,
-                    ParamMode::Explicit,
-                    AllowReturnTypeNotation::No,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Path),
-                    None,
-                );
-
-                let lowered_args = self.arena.alloc_from_iter(args.iter().map(|arg| {
-                    let const_arg = self.lower_expr_to_const_arg_direct(arg);
-                    &*self.arena.alloc(const_arg)
-                }));
-
-                ConstArg {
-                    hir_id: self.next_id(),
-                    kind: hir::ConstArgKind::TupleCall(qpath, lowered_args),
-                    span,
-                }
             }
-            ExprKind::Tup(exprs) => {
+            None => hir::ConstItemRhs::Body(self.lower_const_body(span, None)),
-                let exprs = self.arena.alloc_from_iter(exprs.iter().map(|expr| {
-                    let expr = self.lower_expr_to_const_arg_direct(&expr);
-                    &*self.arena.alloc(expr)
-                }));
-
-                ConstArg { hir_id: self.next_id(), kind: hir::ConstArgKind::Tup(exprs), span }
-            }
-            ExprKind::Path(qself, path) => {
-                let qpath = self.lower_qpath(
-                    expr.id,
-                    qself,
-                    path,
-                    ParamMode::Explicit,
-                    AllowReturnTypeNotation::No,
-                    // FIXME(mgca): update for `fn foo() -> Bar<FOO<impl Trait>>` support
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Path),
-                    None,
-                );
-
-                ConstArg { hir_id: self.next_id(), kind: hir::ConstArgKind::Path(qpath), span }
-            }
-            ExprKind::Struct(se) => {
-                let path = self.lower_qpath(
-                    expr.id,
-                    &se.qself,
-                    &se.path,
-                    // FIXME(mgca): we may want this to be `Optional` instead, but
-                    // we would also need to make sure that HIR ty lowering errors
-                    // when these paths wind up in signatures.
-                    ParamMode::Explicit,
-                    AllowReturnTypeNotation::No,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Path),
-                    None,
-                );
-
-                let fields = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
-                    let hir_id = self.lower_node_id(f.id);
-                    // FIXME(mgca): This might result in lowering attributes that
-                    // then go unused as the `Target::ExprField` is not actually
-                    // corresponding to `Node::ExprField`.
-                    self.lower_attrs(hir_id, &f.attrs, f.span, Target::ExprField);
-                    let expr = self.lower_expr_to_const_arg_direct(&f.expr);
-
-                    &*self.arena.alloc(hir::ConstArgExprField {
-                        hir_id,
-                        field: self.lower_ident(f.ident),
-                        expr: self.arena.alloc(expr),
-                        span: self.lower_span(f.span),
-                    })
-                }));
-
-                ConstArg {
-                    hir_id: self.next_id(),
-                    kind: hir::ConstArgKind::Struct(path, fields),
-                    span,
-                }
-            }
-            ExprKind::Array(elements) => {
-                let lowered_elems = self.arena.alloc_from_iter(elements.iter().map(|element| {
-                    let const_arg = self.lower_expr_to_const_arg_direct(element);
-                    &*self.arena.alloc(const_arg)
-                }));
-                let array_expr = self.arena.alloc(hir::ConstArgArrayExpr {
-                    span: self.lower_span(expr.span),
-                    elems: lowered_elems,
-                });
-
-                ConstArg {
-                    hir_id: self.next_id(),
-                    kind: hir::ConstArgKind::Array(array_expr),
-                    span,
-                }
-            }
-            ExprKind::Underscore => ConstArg {
-                hir_id: self.lower_node_id(expr.id),
-                kind: hir::ConstArgKind::Infer(()),
-                span,
-            },
-            ExprKind::Block(block, _) => {
-                if let [stmt] = block.stmts.as_slice()
-                    && let StmtKind::Expr(expr) = &stmt.kind
-                    && matches!(
-                        expr.kind,
-                        ExprKind::Block(..)
-                            | ExprKind::Path(..)
-                            | ExprKind::Struct(..)
-                            | ExprKind::Call(..)
-                            | ExprKind::Tup(..)
-                            | ExprKind::Array(..)
-                            | ExprKind::ConstBlock(..)
-                    )
-                {
-                    return self.lower_expr_to_const_arg_direct(expr);
-                }
-
-                overly_complex_const(self)
-            }
-            ExprKind::Lit(literal) => {
-                let span = expr.span;
-                let literal = self.lower_lit(literal, span);
-
-                ConstArg {
-                    hir_id: self.lower_node_id(expr.id),
-                    kind: hir::ConstArgKind::Literal { lit: literal.node, negated: false },
-                    span,
-                }
-            }
-            ExprKind::Unary(UnOp::Neg, inner_expr)
-                if let ExprKind::Lit(literal) = &inner_expr.kind =>
-            {
-                let span = expr.span;
-                let literal = self.lower_lit(literal, span);
-
-                ConstArg {
-                    hir_id: self.lower_node_id(expr.id),
-                    kind: hir::ConstArgKind::Literal { lit: literal.node, negated: true },
-                    span,
-                }
-            }
-            ExprKind::ConstBlock(anon_const) => {
-                let def_id = self.local_def_id(anon_const.id);
-                assert_eq!(DefKind::AnonConst, self.tcx.def_kind(def_id));
-                self.lower_anon_const_to_const_arg(anon_const, span)
-            }
-            _ => overly_complex_const(self),
         }
     }
 
     /// See [`hir::ConstArg`] for when to use this function vs
     /// [`Self::lower_anon_const_to_anon_const`].
-    fn lower_anon_const_to_const_arg_and_alloc(
+    fn lower_anon_const_to_const_arg(&mut self, anon: &AnonConst) -> &'hir hir::ConstArg<'hir> {
-        &mut self,
+        self.arena.alloc(self.lower_anon_const_to_const_arg_direct(anon))
-        anon: &AnonConst,
-    ) -> &'hir hir::ConstArg<'hir> {
-        self.arena.alloc(self.lower_anon_const_to_const_arg(anon, anon.value.span))
     }
 
     #[instrument(level = "debug", skip(self))]
-    fn lower_anon_const_to_const_arg(
+    fn lower_anon_const_to_const_arg_direct(&mut self, anon: &AnonConst) -> hir::ConstArg<'hir> {
-        &mut self,
-        anon: &AnonConst,
-        span: Span,
-    ) -> hir::ConstArg<'hir> {
         let tcx = self.tcx;
-
-        // We cannot change parsing depending on feature gates available,
-        // we can only require feature gates to be active as a delayed check.
-        // Thus we just parse anon consts generally and make the real decision
-        // making in ast lowering.
-        // FIXME(min_generic_const_args): revisit once stable
-        if tcx.features().min_generic_const_args() {
-            return match anon.mgca_disambiguation {
-                MgcaDisambiguation::AnonConst => {
-                    let lowered_anon = self.lower_anon_const_to_anon_const(anon, span);
-                    ConstArg {
-                        hir_id: self.next_id(),
-                        kind: hir::ConstArgKind::Anon(lowered_anon),
-                        span: lowered_anon.span,
-                    }
-                }
-                MgcaDisambiguation::Direct => self.lower_expr_to_const_arg_direct(&anon.value),
-            };
-        }
-
         // Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments
         // currently have to be wrapped in curly brackets, so it's necessary to special-case.
         let expr = if let ExprKind::Block(block, _) = &anon.value.kind
@@ -2616,12 +2378,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         } else {
             &anon.value
         };
-
         let maybe_res =
             self.resolver.get_partial_res(expr.id).and_then(|partial_res| partial_res.full_res());
         if let ExprKind::Path(qself, path) = &expr.kind
-            && path.is_potential_trivial_const_arg()
+            && path.is_potential_trivial_const_arg(tcx.features().min_generic_const_args())
-            && matches!(maybe_res, Some(Res::Def(DefKind::ConstParam, _)))
+            && (tcx.features().min_generic_const_args()
+                || matches!(maybe_res, Some(Res::Def(DefKind::ConstParam, _))))
         {
             let qpath = self.lower_qpath(
                 expr.id,
@@ -2629,6 +2391,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 path,
                 ParamMode::Explicit,
                 AllowReturnTypeNotation::No,
+                // FIXME(mgca): update for `fn foo() -> Bar<FOO<impl Trait>>` support
                 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                 None,
             );
@@ -2636,25 +2399,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             return ConstArg {
                 hir_id: self.lower_node_id(anon.id),
                 kind: hir::ConstArgKind::Path(qpath),
-                span: self.lower_span(expr.span),
             };
         }
 
-        let lowered_anon = self.lower_anon_const_to_anon_const(anon, anon.value.span);
+        let lowered_anon = self.lower_anon_const_to_anon_const(anon);
-        ConstArg {
+        ConstArg { hir_id: self.next_id(), kind: hir::ConstArgKind::Anon(lowered_anon) }
-            hir_id: self.next_id(),
-            kind: hir::ConstArgKind::Anon(lowered_anon),
-            span: self.lower_span(expr.span),
-        }
     }
 
     /// See [`hir::ConstArg`] for when to use this function vs
     /// [`Self::lower_anon_const_to_const_arg`].
-    fn lower_anon_const_to_anon_const(
+    fn lower_anon_const_to_anon_const(&mut self, c: &AnonConst) -> &'hir hir::AnonConst {
-        &mut self,
-        c: &AnonConst,
-        span: Span,
-    ) -> &'hir hir::AnonConst {
         self.arena.alloc(self.with_new_scopes(c.value.span, |this| {
             let def_id = this.local_def_id(c.id);
             let hir_id = this.lower_node_id(c.id);
@@ -2662,7 +2416,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 def_id,
                 hir_id,
                 body: this.lower_const_body(c.value.span, Some(&c.value)),
-                span: this.lower_span(span),
+                span: this.lower_span(c.value.span),
             }
         }))
     }

compiler/rustc_ast_lowering/src/pat.rs

@@ -399,6 +399,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             ExprKind::Lit(lit) => {
                 hir::PatExprKind::Lit { lit: self.lower_lit(lit, span), negated: false }
             }
+            ExprKind::ConstBlock(c) => hir::PatExprKind::ConstBlock(self.lower_const_block(c)),
             ExprKind::IncludedBytes(byte_sym) => hir::PatExprKind::Lit {
                 lit: respan(span, LitKind::ByteStr(*byte_sym, StrStyle::Cooked)),
                 negated: false,
@@ -418,12 +419,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 hir::PatExprKind::Lit { lit: self.lower_lit(lit, span), negated: true }
             }
             _ => {
-                let is_const_block = matches!(expr.kind, ExprKind::ConstBlock(_));
                 let pattern_from_macro = expr.is_approximately_pattern();
                 let guar = self.dcx().emit_err(ArbitraryExpressionInPattern {
                     span,
                     pattern_from_macro_note: pattern_from_macro,
-                    const_block_in_pattern_help: is_const_block,
                 });
                 err(guar)
             }
@@ -444,18 +443,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let pat_hir_id = self.lower_node_id(pattern.id);
         let node = match &pattern.kind {
             TyPatKind::Range(e1, e2, Spanned { node: end, span }) => hir::TyPatKind::Range(
-                e1.as_deref()
+                e1.as_deref().map(|e| self.lower_anon_const_to_const_arg(e)).unwrap_or_else(|| {
-                    .map(|e| self.lower_anon_const_to_const_arg_and_alloc(e))
+                    self.lower_ty_pat_range_end(
-                    .unwrap_or_else(|| {
+                        hir::LangItem::RangeMin,
-                        self.lower_ty_pat_range_end(
+                        span.shrink_to_lo(),
-                            hir::LangItem::RangeMin,
+                        base_type,
-                            span.shrink_to_lo(),
+                    )
-                            base_type,
+                }),
-                        )
-                    }),
                 e2.as_deref()
                     .map(|e| match end {
-                        RangeEnd::Included(..) => self.lower_anon_const_to_const_arg_and_alloc(e),
+                        RangeEnd::Included(..) => self.lower_anon_const_to_const_arg(e),
                         RangeEnd::Excluded => self.lower_excluded_range_end(e),
                     })
                     .unwrap_or_else(|| {
@@ -513,7 +510,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.arena.alloc(hir::ConstArg {
             hir_id: self.next_id(),
             kind: hir::ConstArgKind::Anon(self.arena.alloc(anon_const)),
-            span,
         })
     }
 
@@ -558,6 +554,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             })
         });
         let hir_id = self.next_id();
-        self.arena.alloc(hir::ConstArg { kind: hir::ConstArgKind::Anon(ct), hir_id, span })
+        self.arena.alloc(hir::ConstArg { kind: hir::ConstArgKind::Anon(ct), hir_id })
     }
 }

compiler/rustc_ast_lowering/src/path.rs

@@ -36,9 +36,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let qself = qself
             .as_ref()
             // Reject cases like `<impl Trait>::Assoc` and `<impl Trait as Trait>::Assoc`.
-            .map(|q| {
+            .map(|q| self.lower_ty(&q.ty, ImplTraitContext::Disallowed(ImplTraitPosition::Path)));
-                self.lower_ty_alloc(&q.ty, ImplTraitContext::Disallowed(ImplTraitPosition::Path))
-            });
 
         let partial_res =
             self.resolver.get_partial_res(id).unwrap_or_else(|| PartialRes::new(Res::Err));
@@ -512,7 +510,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // we generally don't permit such things (see #51008).
         let ParenthesizedArgs { span, inputs, inputs_span, output } = data;
         let inputs = self.arena.alloc_from_iter(inputs.iter().map(|ty| {
-            self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitParam))
+            self.lower_ty_direct(ty, ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitParam))
         }));
         let output_ty = match output {
             // Only allow `impl Trait` in return position. i.e.:
@@ -522,9 +520,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             // ```
             FnRetTy::Ty(ty) if matches!(itctx, ImplTraitContext::OpaqueTy { .. }) => {
                 if self.tcx.features().impl_trait_in_fn_trait_return() {
-                    self.lower_ty_alloc(ty, itctx)
+                    self.lower_ty(ty, itctx)
                 } else {
-                    self.lower_ty_alloc(
+                    self.lower_ty(
                         ty,
                         ImplTraitContext::FeatureGated(
                             ImplTraitPosition::FnTraitReturn,
@@ -533,8 +531,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     )
                 }
             }
-            FnRetTy::Ty(ty) => self
+            FnRetTy::Ty(ty) => {
-                .lower_ty_alloc(ty, ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitReturn)),
+                self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitReturn))
+            }
             FnRetTy::Default(_) => self.arena.alloc(self.ty_tup(*span, &[])),
         };
         let args = smallvec![GenericArg::Type(

compiler/rustc_ast_lowering/src/stability.rs

@@ -29,6 +29,7 @@ pub(crate) fn extern_abi_enabled(
     })
 }
 
+#[allow(rustc::untranslatable_diagnostic)]
 pub(crate) fn gate_unstable_abi(sess: &Session, features: &Features, span: Span, abi: ExternAbi) {
     match extern_abi_enabled(features, span, abi) {
         Ok(_) => (),
@@ -95,11 +96,6 @@ pub fn extern_abi_stability(abi: ExternAbi) -> Result<(), UnstableAbi> {
         ExternAbi::RustCold => {
             Err(UnstableAbi { abi, feature: sym::rust_cold_cc, explain: GateReason::Experimental })
         }
-        ExternAbi::RustPreserveNone => Err(UnstableAbi {
-            abi,
-            feature: sym::rust_preserve_none_cc,
-            explain: GateReason::Experimental,
-        }),
         ExternAbi::RustInvalid => {
             Err(UnstableAbi { abi, feature: sym::rustc_attrs, explain: GateReason::ImplDetail })
         }

compiler/rustc_ast_passes/Cargo.toml

@@ -13,6 +13,7 @@ rustc_attr_parsing = { path = "../rustc_attr_parsing" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
+rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }

compiler/rustc_ast_passes/messages.ftl

@@ -0,0 +1,340 @@
+ast_passes_abi_cannot_be_coroutine =
+    functions with the {$abi} ABI cannot be `{$coroutine_kind_str}`
+    .suggestion = remove the `{$coroutine_kind_str}` keyword from this definition
+
+ast_passes_abi_custom_safe_foreign_function =
+    foreign functions with the "custom" ABI cannot be safe
+    .suggestion = remove the `safe` keyword from this definition
+
+ast_passes_abi_custom_safe_function =
+    functions with the "custom" ABI must be unsafe
+    .suggestion = add the `unsafe` keyword to this definition
+
+ast_passes_abi_must_not_have_parameters_or_return_type=
+    invalid signature for `extern {$abi}` function
+    .note = functions with the {$abi} ABI cannot have any parameters or return type
+    .suggestion = remove the parameters and return type
+
+ast_passes_abi_must_not_have_return_type=
+    invalid signature for `extern {$abi}` function
+    .note = functions with the {$abi} ABI cannot have a return type
+    .help = remove the return type
+
+ast_passes_abi_x86_interrupt =
+    invalid signature for `extern "x86-interrupt"` function
+    .note = functions with the "x86-interrupt" ABI must be have either 1 or 2 parameters (but found {$param_count})
+
+ast_passes_assoc_const_without_body =
+    associated constant in `impl` without body
+    .suggestion = provide a definition for the constant
+
+ast_passes_assoc_fn_without_body =
+    associated function in `impl` without body
+    .suggestion = provide a definition for the function
+
+ast_passes_assoc_type_without_body =
+    associated type in `impl` without body
+    .suggestion = provide a definition for the type
+
+ast_passes_async_fn_in_const_trait_or_trait_impl =
+    async functions are not allowed in `const` {$context ->
+        [trait_impl] trait impls
+        [impl] impls
+        *[trait] traits
+    }
+    .label = associated functions of `const` cannot be declared `async`
+
+ast_passes_at_least_one_trait = at least one trait must be specified
+
+ast_passes_auto_generic = auto traits cannot have generic parameters
+    .label = auto trait cannot have generic parameters
+    .suggestion = remove the parameters
+
+ast_passes_auto_items = auto traits cannot have associated items
+    .label = {ast_passes_auto_items}
+    .suggestion = remove the associated items
+
+ast_passes_auto_super_lifetime = auto traits cannot have super traits or lifetime bounds
+    .label = {ast_passes_auto_super_lifetime}
+    .suggestion = remove the super traits or lifetime bounds
+
+ast_passes_body_in_extern = incorrect `{$kind}` inside `extern` block
+    .cannot_have = cannot have a body
+    .invalid = the invalid body
+    .existing = `extern` blocks define existing foreign {$kind}s and {$kind}s inside of them cannot have a body
+
+ast_passes_bound_in_context = bounds on `type`s in {$ctx} have no effect
+
+ast_passes_c_variadic_bad_extern = `...` is not supported for `extern "{$abi}"` functions
+    .label = `extern "{$abi}"` because of this
+    .help = only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
+
+ast_passes_c_variadic_bad_naked_extern = `...` is not supported for `extern "{$abi}"` naked functions
+    .label = `extern "{$abi}"` because of this
+    .help = C-variadic function must have a compatible calling convention
+
+ast_passes_c_variadic_must_be_unsafe =
+    functions with a C variable argument list must be unsafe
+    .suggestion = add the `unsafe` keyword to this definition
+
+ast_passes_c_variadic_no_extern = `...` is not supported for non-extern functions
+    .help = only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
+
+ast_passes_c_variadic_not_supported = the `{$target}` target does not support c-variadic functions
+
+ast_passes_const_and_c_variadic = functions cannot be both `const` and C-variadic
+    .const = `const` because of this
+    .variadic = C-variadic because of this
+
+ast_passes_const_and_coroutine = functions cannot be both `const` and `{$coroutine_kind}`
+    .const = `const` because of this
+    .coroutine = `{$coroutine_kind}` because of this
+    .label = {""}
+
+ast_passes_const_auto_trait = auto traits cannot be const
+    .help = remove the `const` keyword
+
+ast_passes_const_bound_trait_object = const trait bounds are not allowed in trait object types
+
+ast_passes_const_without_body =
+    free constant item without body
+    .suggestion = provide a definition for the constant
+
+ast_passes_constraint_on_negative_bound =
+    associated type constraints not allowed on negative bounds
+
+ast_passes_coroutine_and_c_variadic = functions cannot be both `{$coroutine_kind}` and C-variadic
+    .const = `{$coroutine_kind}` because of this
+    .variadic = C-variadic because of this
+
+ast_passes_equality_in_where = equality constraints are not yet supported in `where` clauses
+    .label = not supported
+    .suggestion = if `{$ident}` is an associated type you're trying to set, use the associated type binding syntax
+    .suggestion_path = if `{$trait_segment}::{$potential_assoc}` is an associated type you're trying to set, use the associated type binding syntax
+    .note = see issue #20041 <https://github.com/rust-lang/rust/issues/20041> for more information
+
+ast_passes_extern_block_suggestion = if you meant to declare an externally defined function, use an `extern` block
+
+ast_passes_extern_fn_qualifiers = functions in `extern` blocks cannot have `{$kw}` qualifier
+    .label = in this `extern` block
+    .suggestion = remove the `{$kw}` qualifier
+
+ast_passes_extern_invalid_safety = items in `extern` blocks without an `unsafe` qualifier cannot have safety qualifiers
+    .suggestion = add `unsafe` to this `extern` block
+
+ast_passes_extern_item_ascii = items in `extern` blocks cannot use non-ascii identifiers
+    .label = in this `extern` block
+    .note = this limitation may be lifted in the future; see issue #83942 <https://github.com/rust-lang/rust/issues/83942> for more information
+
+ast_passes_extern_keyword_link = for more information, visit https://doc.rust-lang.org/std/keyword.extern.html
+
+ast_passes_extern_types_cannot = `type`s inside `extern` blocks cannot have {$descr}
+    .suggestion = remove the {$remove_descr}
+    .label = `extern` block begins here
+
+ast_passes_extern_without_abi = `extern` declarations without an explicit ABI are disallowed
+    .suggestion = specify an ABI
+    .help = prior to Rust 2024, a default ABI was inferred
+
+ast_passes_extern_without_abi_sugg = `extern` declarations without an explicit ABI are deprecated
+    .label = ABI should be specified here
+    .suggestion = explicitly specify the {$default_abi} ABI
+
+ast_passes_feature_on_non_nightly = `#![feature]` may not be used on the {$channel} release channel
+    .suggestion = remove the attribute
+    .stable_since = the feature `{$name}` has been stable since `{$since}` and no longer requires an attribute to enable
+
+ast_passes_fieldless_union = unions cannot have zero fields
+
+ast_passes_fn_body_extern = incorrect function inside `extern` block
+    .cannot_have = cannot have a body
+    .suggestion = remove the invalid body
+    .help = you might have meant to write a function accessible through FFI, which can be done by writing `extern fn` outside of the `extern` block
+    .label = `extern` blocks define existing foreign functions and functions inside of them cannot have a body
+
+ast_passes_fn_param_c_var_args_not_last =
+    `...` must be the last argument of a C-variadic function
+
+ast_passes_fn_param_doc_comment =
+    documentation comments cannot be applied to function parameters
+    .label = doc comments are not allowed here
+
+ast_passes_fn_param_forbidden_attr =
+    allow, cfg, cfg_attr, deny, expect, forbid, and warn are the only allowed built-in attributes in function parameters
+
+ast_passes_fn_param_forbidden_self =
+    `self` parameter is only allowed in associated functions
+    .label = not semantically valid as function parameter
+    .note = associated functions are those in `impl` or `trait` definitions
+
+ast_passes_fn_param_too_many =
+    function can not have more than {$max_num_args} arguments
+
+ast_passes_fn_ptr_invalid_safety = function pointers cannot be declared with `safe` safety qualifier
+    .suggestion = remove safe from this item
+
+ast_passes_fn_without_body =
+    free function without a body
+    .suggestion = provide a definition for the function
+
+ast_passes_forbidden_bound =
+    bounds cannot be used in this context
+
+ast_passes_forbidden_const_param =
+    late-bound const parameters cannot be used currently
+
+ast_passes_forbidden_default =
+    `default` is only allowed on items in trait impls
+    .label = `default` because of this
+
+ast_passes_forbidden_non_lifetime_param =
+    only lifetime parameters can be used in this context
+
+ast_passes_generic_before_constraints = generic arguments must come before the first constraint
+    .constraints = {$constraint_len ->
+    [one] constraint
+    *[other] constraints
+    }
+    .args = generic {$args_len ->
+    [one] argument
+    *[other] arguments
+    }
+    .empty_string = {""},
+    .suggestion = move the {$constraint_len ->
+    [one] constraint
+    *[other] constraints
+    } after the generic {$args_len ->
+    [one] argument
+    *[other] arguments
+    }
+
+ast_passes_generic_default_trailing = generic parameters with a default must be trailing
+
+ast_passes_impl_fn_const =
+    redundant `const` fn marker in const impl
+    .parent_constness = this declares all associated functions implicitly const
+    .label = remove the `const`
+
+ast_passes_incompatible_features = `{$f1}` and `{$f2}` are incompatible, using them at the same time is not allowed
+    .help = remove one of these features
+
+ast_passes_item_invalid_safety = items outside of `unsafe extern {"{ }"}` cannot be declared with `safe` safety qualifier
+    .suggestion = remove safe from this item
+
+ast_passes_item_underscore = `{$kind}` items in this context need a name
+    .label = `_` is not a valid name for this `{$kind}` item
+
+ast_passes_match_arm_with_no_body =
+    `match` arm with no body
+    .suggestion = add a body after the pattern
+
+ast_passes_missing_unsafe_on_extern = extern blocks must be unsafe
+    .suggestion = needs `unsafe` before the extern keyword
+
+ast_passes_missing_unsafe_on_extern_lint = extern blocks should be unsafe
+    .suggestion = needs `unsafe` before the extern keyword
+
+ast_passes_module_nonascii = trying to load file for module `{$name}` with non-ascii identifier name
+    .help = consider using the `#[path]` attribute to specify filesystem path
+
+ast_passes_negative_bound_not_supported =
+    negative bounds are not supported
+
+ast_passes_negative_bound_with_parenthetical_notation =
+    parenthetical notation may not be used for negative bounds
+
+ast_passes_nested_impl_trait = nested `impl Trait` is not allowed
+    .outer = outer `impl Trait`
+    .inner = nested `impl Trait` here
+
+ast_passes_nested_lifetimes = nested quantification of lifetimes
+
+ast_passes_nomangle_ascii = `#[no_mangle]` requires ASCII identifier
+
+ast_passes_obsolete_auto = `impl Trait for .. {"{}"}` is an obsolete syntax
+    .help = use `auto trait Trait {"{}"}` instead
+
+ast_passes_out_of_order_params = {$param_ord} parameters must be declared prior to {$max_param} parameters
+    .suggestion = reorder the parameters: lifetimes, then consts and types
+
+ast_passes_pattern_in_bodiless = patterns aren't allowed in functions without bodies
+    .label = pattern not allowed in function without body
+
+ast_passes_pattern_in_fn_pointer = patterns aren't allowed in function pointer types
+
+ast_passes_pattern_in_foreign = patterns aren't allowed in foreign function declarations
+    .label = pattern not allowed in foreign function
+
+ast_passes_precise_capturing_duplicated = duplicate `use<...>` precise capturing syntax
+    .label = second `use<...>` here
+
+ast_passes_precise_capturing_not_allowed_here = `use<...>` precise capturing syntax not allowed in {$loc}
+
+ast_passes_static_without_body =
+    free static item without body
+    .suggestion = provide a definition for the static
+
+ast_passes_tilde_const_disallowed = `[const]` is not allowed here
+    .closure = closures cannot have `[const]` trait bounds
+    .function = this function is not `const`, so it cannot have `[const]` trait bounds
+    .trait = this trait is not `const`, so it cannot have `[const]` trait bounds
+    .trait_impl = this impl is not `const`, so it cannot have `[const]` trait bounds
+    .impl = inherent impls cannot have `[const]` trait bounds
+    .trait_assoc_ty = associated types in non-`const` traits cannot have `[const]` trait bounds
+    .trait_impl_assoc_ty = associated types in non-const impls cannot have `[const]` trait bounds
+    .inherent_assoc_ty = inherent associated types cannot have `[const]` trait bounds
+    .struct = structs cannot have `[const]` trait bounds
+    .enum = enums cannot have `[const]` trait bounds
+    .union = unions cannot have `[const]` trait bounds
+    .anon_const = anonymous constants cannot have `[const]` trait bounds
+    .object = trait objects cannot have `[const]` trait bounds
+    .item = this item cannot have `[const]` trait bounds
+
+ast_passes_trait_fn_const =
+    functions in {$in_impl ->
+        [true] trait impls
+        *[false] traits
+    } cannot be declared const
+    .label = functions in {$in_impl ->
+        [true] trait impls
+        *[false] traits
+    } cannot be const
+    .const_context_label = this declares all associated functions implicitly const
+    .remove_const_sugg = remove the `const`{$requires_multiple_changes ->
+        [true] {" ..."}
+        *[false] {""}
+    }
+    .make_impl_const_sugg = ... and declare the impl to be const instead
+    .make_trait_const_sugg = ... and declare the trait to be const instead
+
+ast_passes_trait_object_single_bound = only a single explicit lifetime bound is permitted
+
+ast_passes_ty_alias_without_body =
+    free type alias without body
+    .suggestion = provide a definition for the type
+
+ast_passes_unsafe_item = {$kind} cannot be declared unsafe
+
+ast_passes_unsafe_negative_impl = negative impls cannot be unsafe
+    .negative = negative because of this
+    .unsafe = unsafe because of this
+
+ast_passes_unsafe_static =
+    static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+
+ast_passes_visibility_not_permitted =
+    visibility qualifiers are not permitted here
+    .enum_variant = enum variants and their fields always share the visibility of the enum they are in
+    .trait_impl = trait items always share the visibility of their trait
+    .individual_impl_items = place qualifiers on individual impl items instead
+    .individual_foreign_items = place qualifiers on individual foreign items instead
+    .remove_qualifier_sugg = remove the qualifier
+
+ast_passes_where_clause_after_type_alias = where clauses are not allowed after the type for type aliases
+    .note = see issue #112792 <https://github.com/rust-lang/rust/issues/112792> for more information
+    .help = add `#![feature(lazy_type_alias)]` to the crate attributes to enable
+
+ast_passes_where_clause_before_type_alias = where clauses are not allowed before the type for type aliases
+    .note = see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
+    .remove_suggestion = remove this `where`
+    .move_suggestion = move it to the end of the type declaration

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -33,7 +33,7 @@ use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
     DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, MISSING_UNSAFE_ON_EXTERN,
-    PATTERNS_IN_FNS_WITHOUT_BODY, UNUSED_VISIBILITIES,
+    PATTERNS_IN_FNS_WITHOUT_BODY,
 };
 use rustc_session::parse::feature_err;
 use rustc_span::{Ident, Span, kw, sym};
@@ -65,28 +65,6 @@ impl TraitOrImpl {
     }
 }
 
-enum AllowDefault {
-    Yes,
-    No,
-}
-
-impl AllowDefault {
-    fn when(b: bool) -> Self {
-        if b { Self::Yes } else { Self::No }
-    }
-}
-
-enum AllowFinal {
-    Yes,
-    No,
-}
-
-impl AllowFinal {
-    fn when(b: bool) -> Self {
-        if b { Self::Yes } else { Self::No }
-    }
-}
-
 struct AstValidator<'a> {
     sess: &'a Session,
     features: &'a Features,
@@ -422,18 +400,10 @@ impl<'a> AstValidator<'a> {
                     CanonAbi::C
                     | CanonAbi::Rust
                     | CanonAbi::RustCold
-                    | CanonAbi::RustPreserveNone
                     | CanonAbi::Arm(_)
+                    | CanonAbi::GpuKernel
                     | CanonAbi::X86(_) => { /* nothing to check */ }
 
-                    CanonAbi::GpuKernel => {
-                        // An `extern "gpu-kernel"` function cannot be `async` and/or `gen`.
-                        self.reject_coroutine(abi, sig);
-
-                        // An `extern "gpu-kernel"` function cannot return a value.
-                        self.reject_return(abi, sig);
-                    }
-
                     CanonAbi::Custom => {
                         // An `extern "custom"` function must be unsafe.
                         self.reject_safe_fn(abi, ctxt, sig);
@@ -463,7 +433,18 @@ impl<'a> AstValidator<'a> {
                                 self.dcx().emit_err(errors::AbiX86Interrupt { spans, param_count });
                             }
 
-                            self.reject_return(abi, sig);
+                            if let FnRetTy::Ty(ref ret_ty) = sig.decl.output
+                                && match &ret_ty.kind {
+                                    TyKind::Never => false,
+                                    TyKind::Tup(tup) if tup.is_empty() => false,
+                                    _ => true,
+                                }
+                            {
+                                self.dcx().emit_err(errors::AbiMustNotHaveReturnType {
+                                    span: ret_ty.span,
+                                    abi,
+                                });
+                            }
                         } else {
                             // An `extern "interrupt"` function must have type `fn()`.
                             self.reject_params_or_return(abi, ident, sig);
@@ -515,18 +496,6 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn reject_return(&self, abi: ExternAbi, sig: &FnSig) {
-        if let FnRetTy::Ty(ref ret_ty) = sig.decl.output
-            && match &ret_ty.kind {
-                TyKind::Never => false,
-                TyKind::Tup(tup) if tup.is_empty() => false,
-                _ => true,
-            }
-        {
-            self.dcx().emit_err(errors::AbiMustNotHaveReturnType { span: ret_ty.span, abi });
-        }
-    }
-
     fn reject_params_or_return(&self, abi: ExternAbi, ident: &Ident, sig: &FnSig) {
         let mut spans: Vec<_> = sig.decl.inputs.iter().map(|p| p.span).collect();
         if let FnRetTy::Ty(ref ret_ty) = sig.decl.output
@@ -585,32 +554,10 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn check_defaultness(
+    fn check_defaultness(&self, span: Span, defaultness: Defaultness) {
-        &self,
+        if let Defaultness::Default(def_span) = defaultness {
-        span: Span,
+            let span = self.sess.source_map().guess_head_span(span);
-        defaultness: Defaultness,
+            self.dcx().emit_err(errors::ForbiddenDefault { span, def_span });
-        allow_default: AllowDefault,
-        allow_final: AllowFinal,
-    ) {
-        match defaultness {
-            Defaultness::Default(def_span) if matches!(allow_default, AllowDefault::No) => {
-                let span = self.sess.source_map().guess_head_span(span);
-                self.dcx().emit_err(errors::ForbiddenDefault { span, def_span });
-            }
-            Defaultness::Final(def_span) if matches!(allow_final, AllowFinal::No) => {
-                let span = self.sess.source_map().guess_head_span(span);
-                self.dcx().emit_err(errors::ForbiddenFinal { span, def_span });
-            }
-            _ => (),
-        }
-    }
-
-    fn check_final_has_body(&self, item: &Item<AssocItemKind>, defaultness: Defaultness) {
-        if let AssocItemKind::Fn(box Fn { body: None, .. }) = &item.kind
-            && let Defaultness::Final(def_span) = defaultness
-        {
-            let span = self.sess.source_map().guess_head_span(item.span);
-            self.dcx().emit_err(errors::ForbiddenFinalWithoutBody { span, def_span });
         }
     }
 
@@ -742,11 +689,13 @@ impl<'a> AstValidator<'a> {
             unreachable!("C variable argument list cannot be used in closures")
         };
 
-        if let Const::Yes(_) = sig.header.constness
+        // C-variadics are not yet implemented in const evaluation.
-            && !self.features.enabled(sym::const_c_variadic)
+        if let Const::Yes(const_span) = sig.header.constness {
-        {
+            self.dcx().emit_err(errors::ConstAndCVariadic {
-            let msg = format!("c-variadic const function definitions are unstable");
+                spans: vec![const_span, variadic_param.span],
-            feature_err(&self.sess, sym::const_c_variadic, sig.span, msg).emit();
+                const_span,
+                variadic_span: variadic_param.span,
+            });
         }
 
         if let Some(coroutine_kind) = sig.header.coroutine_kind {
@@ -1230,15 +1179,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     contract: _,
                     body,
                     define_opaque: _,
-                    eii_impls,
                 },
             ) => {
                 self.visit_attrs_vis_ident(&item.attrs, &item.vis, ident);
-                self.check_defaultness(item.span, *defaultness, AllowDefault::No, AllowFinal::No);
+                self.check_defaultness(item.span, *defaultness);
-
-                for EiiImpl { eii_macro_path, .. } in eii_impls {
-                    self.visit_path(eii_macro_path);
-                }
 
                 let is_intrinsic = item.attrs.iter().any(|a| a.has_name(sym::rustc_intrinsic));
                 if body.is_none() && !is_intrinsic && !self.is_sdylib_interface {
@@ -1370,14 +1314,6 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             }
             ItemKind::Struct(ident, generics, vdata) => {
                 self.with_tilde_const(Some(TildeConstReason::Struct { span: item.span }), |this| {
-                    // Scalable vectors can only be tuple structs
-                    let is_scalable_vector =
-                        item.attrs.iter().any(|attr| attr.has_name(sym::rustc_scalable_vector));
-                    if is_scalable_vector && !matches!(vdata, VariantData::Tuple(..)) {
-                        this.dcx()
-                            .emit_err(errors::ScalableVectorNotTupleStruct { span: item.span });
-                    }
-
                     match vdata {
                         VariantData::Struct { fields, .. } => {
                             this.visit_attrs_vis_ident(&item.attrs, &item.vis, ident);
@@ -1403,26 +1339,14 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     }
                 });
             }
-            ItemKind::Const(box ConstItem { defaultness, ident, rhs_kind, .. }) => {
+            ItemKind::Const(box ConstItem { defaultness, rhs, .. }) => {
-                self.check_defaultness(item.span, *defaultness, AllowDefault::No, AllowFinal::No);
+                self.check_defaultness(item.span, *defaultness);
-                if !rhs_kind.has_expr() {
+                if rhs.is_none() {
                     self.dcx().emit_err(errors::ConstWithoutBody {
                         span: item.span,
                         replace_span: self.ending_semi_or_hi(item.span),
                     });
                 }
-                if ident.name == kw::Underscore
-                    && !matches!(item.vis.kind, VisibilityKind::Inherited)
-                    && ident.span.eq_ctxt(item.vis.span)
-                {
-                    self.lint_buffer.buffer_lint(
-                        UNUSED_VISIBILITIES,
-                        item.id,
-                        item.vis.span,
-                        BuiltinLintDiag::UnusedVisibility(item.vis.span),
-                    )
-                }
-
                 visit::walk_item(self, item);
             }
             ItemKind::Static(box StaticItem { expr, safety, .. }) => {
@@ -1442,7 +1366,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             ItemKind::TyAlias(
                 ty_alias @ box TyAlias { defaultness, bounds, after_where_clause, ty, .. },
             ) => {
-                self.check_defaultness(item.span, *defaultness, AllowDefault::No, AllowFinal::No);
+                self.check_defaultness(item.span, *defaultness);
                 if ty.is_none() {
                     self.dcx().emit_err(errors::TyAliasWithoutBody {
                         span: item.span,
@@ -1472,7 +1396,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
     fn visit_foreign_item(&mut self, fi: &'a ForeignItem) {
         match &fi.kind {
             ForeignItemKind::Fn(box Fn { defaultness, ident, sig, body, .. }) => {
-                self.check_defaultness(fi.span, *defaultness, AllowDefault::No, AllowFinal::No);
+                self.check_defaultness(fi.span, *defaultness);
                 self.check_foreign_fn_bodyless(*ident, body.as_deref());
                 self.check_foreign_fn_headerless(sig.header);
                 self.check_foreign_item_ascii_only(*ident);
@@ -1492,7 +1416,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 ty,
                 ..
             }) => {
-                self.check_defaultness(fi.span, *defaultness, AllowDefault::No, AllowFinal::No);
+                self.check_defaultness(fi.span, *defaultness);
                 self.check_foreign_kind_bodyless(*ident, "type", ty.as_ref().map(|b| b.span));
                 self.check_type_no_bounds(bounds, "`extern` blocks");
                 self.check_foreign_ty_genericless(generics, after_where_clause);
@@ -1751,29 +1675,17 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             self.check_nomangle_item_asciionly(ident, item.span);
         }
 
-        let defaultness = item.kind.defaultness();
+        if ctxt == AssocCtxt::Trait || self.outer_trait_or_trait_impl.is_none() {
-        self.check_defaultness(
+            self.check_defaultness(item.span, item.kind.defaultness());
-            item.span,
+        }
-            defaultness,
-            // `default` is allowed on all associated items in impls.
-            AllowDefault::when(matches!(ctxt, AssocCtxt::Impl { .. })),
-            // `final` is allowed on all associated *functions* in traits.
-            AllowFinal::when(
-                ctxt == AssocCtxt::Trait && matches!(item.kind, AssocItemKind::Fn(..)),
-            ),
-        );
-
-        self.check_final_has_body(item, defaultness);
 
         if let AssocCtxt::Impl { .. } = ctxt {
             match &item.kind {
-                AssocItemKind::Const(box ConstItem { rhs_kind, .. }) => {
+                AssocItemKind::Const(box ConstItem { rhs: None, .. }) => {
-                    if !rhs_kind.has_expr() {
+                    self.dcx().emit_err(errors::AssocConstWithoutBody {
-                        self.dcx().emit_err(errors::AssocConstWithoutBody {
+                        span: item.span,
-                            span: item.span,
+                        replace_span: self.ending_semi_or_hi(item.span),
-                            replace_span: self.ending_semi_or_hi(item.span),
+                    });
-                        });
-                    }
                 }
                 AssocItemKind::Fn(box Fn { body, .. }) => {
                     if body.is_none() && !self.is_sdylib_interface {

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -1,6 +1,5 @@
 use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
 use rustc_ast::{self as ast, AttrVec, NodeId, PatKind, attr, token};
-use rustc_errors::msg;
 use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP, BuiltinAttribute, Features};
 use rustc_session::Session;
 use rustc_session::parse::{feature_err, feature_warn};
@@ -14,11 +13,15 @@ use crate::errors;
 macro_rules! gate {
     ($visitor:expr, $feature:ident, $span:expr, $explain:expr) => {{
         if !$visitor.features.$feature() && !$span.allows_unstable(sym::$feature) {
+            #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
             feature_err(&$visitor.sess, sym::$feature, $span, $explain).emit();
         }
     }};
     ($visitor:expr, $feature:ident, $span:expr, $explain:expr, $help:expr) => {{
         if !$visitor.features.$feature() && !$span.allows_unstable(sym::$feature) {
+            // FIXME: make this translatable
+            #[allow(rustc::diagnostic_outside_of_impl)]
+            #[allow(rustc::untranslatable_diagnostic)]
             feature_err(&$visitor.sess, sym::$feature, $span, $explain).with_help($help).emit();
         }
     }};
@@ -28,11 +31,13 @@ macro_rules! gate {
 macro_rules! gate_alt {
     ($visitor:expr, $has_feature:expr, $name:expr, $span:expr, $explain:expr) => {{
         if !$has_feature && !$span.allows_unstable($name) {
+            #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
             feature_err(&$visitor.sess, $name, $span, $explain).emit();
         }
     }};
     ($visitor:expr, $has_feature:expr, $name:expr, $span:expr, $explain:expr, $notes: expr) => {{
         if !$has_feature && !$span.allows_unstable($name) {
+            #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
             let mut diag = feature_err(&$visitor.sess, $name, $span, $explain);
             for note in $notes {
                 diag.note(*note);
@@ -125,7 +130,7 @@ impl<'a> PostExpansionVisitor<'a> {
             &self,
             non_lifetime_binders,
             non_lt_param_spans,
-            msg!("only lifetime parameters can be used in this context")
+            crate::fluent_generated::ast_passes_forbidden_non_lifetime_param
         );
 
         // FIXME(non_lifetime_binders): Const bound params are pretty broken.
@@ -155,7 +160,7 @@ impl<'a> PostExpansionVisitor<'a> {
 
 impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_attribute(&mut self, attr: &ast::Attribute) {
-        let attr_info = attr.name().and_then(|name| BUILTIN_ATTRIBUTE_MAP.get(&name));
+        let attr_info = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
         // Check feature gates for built-in attributes.
         if let Some(BuiltinAttribute {
             gate: AttributeGate::Gated { feature, message, check, notes, .. },
@@ -249,14 +254,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             ast::ItemKind::TyAlias(box ast::TyAlias { ty: Some(ty), .. }) => {
                 self.check_impl_trait(ty, false)
             }
-            ast::ItemKind::Const(box ast::ConstItem {
-                rhs_kind: ast::ConstItemRhsKind::TypeConst { .. },
-                ..
-            }) => {
-                // Make sure this is only allowed if the feature gate is enabled.
-                // #![feature(min_generic_const_args)]
-                gate!(&self, min_generic_const_args, i.span, "top-level `type const` are unstable");
-            }
 
             _ => {}
         }
@@ -304,12 +301,17 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         visit::walk_ty(self, ty)
     }
 
-    fn visit_where_predicate_kind(&mut self, kind: &'a ast::WherePredicateKind) {
+    fn visit_generics(&mut self, g: &'a ast::Generics) {
-        if let ast::WherePredicateKind::BoundPredicate(bound) = kind {
+        for predicate in &g.where_clause.predicates {
-            // A type bound (e.g., `for<'c> Foo: Send + Clone + 'c`).
+            match &predicate.kind {
-            self.check_late_bound_lifetime_defs(&bound.bound_generic_params);
+                ast::WherePredicateKind::BoundPredicate(bound_pred) => {
+                    // A type bound (e.g., `for<'c> Foo: Send + Clone + 'c`).
+                    self.check_late_bound_lifetime_defs(&bound_pred.bound_generic_params);
+                }
+                _ => {}
+            }
         }
-        visit::walk_where_predicate_kind(self, kind);
+        visit::walk_generics(self, g);
     }
 
     fn visit_fn_ret_ty(&mut self, ret_ty: &'a ast::FnRetTy) {
@@ -337,13 +339,9 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
 
     fn visit_expr(&mut self, e: &'a ast::Expr) {
         match e.kind {
-            ast::ExprKind::TryBlock(_, None) => {
+            ast::ExprKind::TryBlock(_) => {
-                // `try { ... }` is old and is only gated post-expansion here.
                 gate!(&self, try_blocks, e.span, "`try` expression is experimental");
             }
-            ast::ExprKind::TryBlock(_, Some(_)) => {
-                // `try_blocks_heterogeneous` is new, and gated pre-expansion instead.
-            }
             ast::ExprKind::Lit(token::Lit {
                 kind: token::LitKind::Float | token::LitKind::Integer,
                 suffix,
@@ -426,20 +424,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 }
                 false
             }
-            ast::AssocItemKind::Const(box ast::ConstItem {
-                rhs_kind: ast::ConstItemRhsKind::TypeConst { .. },
-                ..
-            }) => {
-                // Make sure this is only allowed if the feature gate is enabled.
-                // #![feature(min_generic_const_args)]
-                gate!(
-                    &self,
-                    min_generic_const_args,
-                    i.span,
-                    "associated `type const` are unstable"
-                );
-                false
-            }
             _ => false,
         };
         if let ast::Defaultness::Default(_) = i.kind.defaultness() {
@@ -459,7 +443,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
 pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     maybe_stage_features(sess, features, krate);
     check_incompatible_features(sess, features);
-    check_dependent_features(sess, features);
     check_new_solver_banned_features(sess, features);
 
     let mut visitor = PostExpansionVisitor { sess, features };
@@ -505,6 +488,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
                 && (!visitor.features.gen_blocks() && !span.allows_unstable(sym::gen_blocks))
                 && (!visitor.features.yield_expr() && !span.allows_unstable(sym::yield_expr))
             {
+                #[allow(rustc::untranslatable_diagnostic)]
                 // Emit yield_expr as the error, since that will be sufficient. You can think of it
                 // as coroutines and gen_blocks imply yield_expr.
                 feature_err(&visitor.sess, sym::yield_expr, *span, "yield syntax is experimental")
@@ -518,7 +502,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         half_open_range_patterns_in_slices,
         "half-open range patterns in slices are unstable"
     );
-    gate_all!(try_blocks_heterogeneous, "`try bikeshed` expression is experimental");
+    gate_all!(associated_const_equality, "associated const equality is incomplete");
     gate_all!(yeet_expr, "`do yeet` expression is experimental");
     gate_all!(const_closures, "const closures are experimental");
     gate_all!(builtin_syntax, "`builtin #` syntax is unstable");
@@ -530,44 +514,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(fn_delegation, "functions delegation is not yet fully implemented");
     gate_all!(postfix_match, "postfix match is experimental");
     gate_all!(mut_ref, "mutable by-reference bindings are experimental");
-    gate_all!(min_generic_const_args, "unbraced const blocks as const args are experimental");
-    // associated_const_equality is stabilized as part of min_generic_const_args
-    if let Some(spans) = spans.get(&sym::associated_const_equality) {
-        for span in spans {
-            if !visitor.features.min_generic_const_args()
-                && !span.allows_unstable(sym::min_generic_const_args)
-            {
-                feature_err(
-                    &visitor.sess,
-                    sym::min_generic_const_args,
-                    *span,
-                    "associated const equality is incomplete",
-                )
-                .emit();
-            }
-        }
-    }
-    // `mgca_type_const_syntax` is part of `min_generic_const_args` so either
-    // or both are enabled we don't need to emit a feature error.
-    if let Some(spans) = spans.get(&sym::mgca_type_const_syntax) {
-        for span in spans {
-            if visitor.features.min_generic_const_args()
-                || visitor.features.mgca_type_const_syntax()
-                || span.allows_unstable(sym::min_generic_const_args)
-                || span.allows_unstable(sym::mgca_type_const_syntax)
-            {
-                continue;
-            }
-            feature_err(
-                &visitor.sess,
-                sym::min_generic_const_args,
-                *span,
-                "`type const` syntax is experimental",
-            )
-            .emit();
-        }
-    }
-
     gate_all!(global_registration, "global registration is experimental");
     gate_all!(return_type_notation, "return type notation is experimental");
     gate_all!(pin_ergonomics, "pinned reference syntax is experimental");
@@ -579,8 +525,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(super_let, "`super let` is experimental");
     gate_all!(frontmatter, "frontmatters are experimental");
     gate_all!(coroutines, "coroutine syntax is experimental");
-    gate_all!(const_block_items, "const block items are experimental");
-    gate_all!(final_associated_functions, "`final` on trait functions is experimental");
 
     if !visitor.features.never_patterns() {
         if let Some(spans) = spans.get(&sym::never_patterns) {
@@ -595,6 +539,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
                 if let Ok(snippet) = sm.span_to_snippet(span)
                     && snippet == "!"
                 {
+                    #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
                     feature_err(sess, sym::never_patterns, span, "`!` patterns are experimental")
                         .emit();
                 } else {
@@ -691,27 +636,6 @@ fn check_incompatible_features(sess: &Session, features: &Features) {
     }
 }
 
-fn check_dependent_features(sess: &Session, features: &Features) {
-    for &(parent, children) in
-        rustc_feature::DEPENDENT_FEATURES.iter().filter(|(parent, _)| features.enabled(*parent))
-    {
-        if children.iter().any(|f| !features.enabled(*f)) {
-            let parent_span = features
-                .enabled_features_iter_stable_order()
-                .find_map(|(name, span)| (name == parent).then_some(span))
-                .unwrap();
-            // FIXME: should probably format this in fluent instead of here
-            let missing = children
-                .iter()
-                .filter(|f| !features.enabled(**f))
-                .map(|s| format!("`{}`", s.as_str()))
-                .intersperse(String::from(", "))
-                .collect();
-            sess.dcx().emit_err(errors::MissingDependentFeatures { parent_span, parent, missing });
-        }
-    }
-}
-
 fn check_new_solver_banned_features(sess: &Session, features: &Features) {
     if !sess.opts.unstable_opts.next_solver.globally {
         return;

compiler/rustc_ast_passes/src/lib.rs

@@ -5,10 +5,11 @@
 // tidy-alphabetical-start
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
-#![feature(iter_intersperse)]
 #![feature(iter_is_partitioned)]
 // tidy-alphabetical-end
 
 pub mod ast_validation;
 mod errors;
 pub mod feature_gate;
+
+rustc_fluent_macro::fluent_messages! { "../messages.ftl" }

compiler/rustc_ast_pretty/src/pprust/mod.rs

@@ -33,9 +33,6 @@ pub fn where_bound_predicate_to_string(where_bound_predicate: &ast::WhereBoundPr
     State::new().where_bound_predicate_to_string(where_bound_predicate)
 }
 
-/// # Panics
-///
-/// Panics if `pat.kind` is `PatKind::Missing`.
 pub fn pat_to_string(pat: &ast::Pat) -> String {
     State::new().pat_to_string(pat)
 }

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -10,7 +10,7 @@ use std::borrow::Cow;
 use std::sync::Arc;
 
 use rustc_ast::attr::AttrIdGenerator;
-use rustc_ast::token::{self, CommentKind, Delimiter, DocFragmentKind, Token, TokenKind};
+use rustc_ast::token::{self, CommentKind, Delimiter, Token, TokenKind};
 use rustc_ast::tokenstream::{Spacing, TokenStream, TokenTree};
 use rustc_ast::util::classify;
 use rustc_ast::util::comments::{Comment, CommentStyle};
@@ -381,24 +381,15 @@ fn space_between(tt1: &TokenTree, tt2: &TokenTree) -> bool {
 }
 
 pub fn doc_comment_to_string(
-    fragment_kind: DocFragmentKind,
+    comment_kind: CommentKind,
     attr_style: ast::AttrStyle,
     data: Symbol,
 ) -> String {
-    match fragment_kind {
+    match (comment_kind, attr_style) {
-        DocFragmentKind::Sugared(comment_kind) => match (comment_kind, attr_style) {
+        (CommentKind::Line, ast::AttrStyle::Outer) => format!("///{data}"),
-            (CommentKind::Line, ast::AttrStyle::Outer) => format!("///{data}"),
+        (CommentKind::Line, ast::AttrStyle::Inner) => format!("//!{data}"),
-            (CommentKind::Line, ast::AttrStyle::Inner) => format!("//!{data}"),
+        (CommentKind::Block, ast::AttrStyle::Outer) => format!("/**{data}*/"),
-            (CommentKind::Block, ast::AttrStyle::Outer) => format!("/**{data}*/"),
+        (CommentKind::Block, ast::AttrStyle::Inner) => format!("/*!{data}*/"),
-            (CommentKind::Block, ast::AttrStyle::Inner) => format!("/*!{data}*/"),
-        },
-        DocFragmentKind::Raw(_) => {
-            format!(
-                "#{}[doc = {:?}]",
-                if attr_style == ast::AttrStyle::Inner { "!" } else { "" },
-                data.to_string(),
-            )
-        }
     }
 }
 
@@ -674,11 +665,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                 self.word("]");
             }
             ast::AttrKind::DocComment(comment_kind, data) => {
-                self.word(doc_comment_to_string(
+                self.word(doc_comment_to_string(*comment_kind, attr.style, *data));
-                    DocFragmentKind::Sugared(*comment_kind),
-                    attr.style,
-                    *data,
-                ));
                 self.hardbreak()
             }
         }
@@ -694,7 +681,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
             }
             ast::Safety::Default | ast::Safety::Safe(_) => {}
         }
-        match &item.args.unparsed_ref().expect("Parsed attributes are never printed") {
+        match &item.args {
             AttrArgs::Delimited(DelimArgs { dspan: _, delim, tokens }) => self.print_mac_common(
                 Some(MacHeader::Path(&item.path)),
                 false,
@@ -865,17 +852,6 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         sp: Span,
         print_visibility: impl FnOnce(&mut Self),
     ) {
-        if let Some(eii_decl) = &macro_def.eii_declaration {
-            self.word("#[eii_declaration(");
-            self.print_path(&eii_decl.foreign_item, false, 0);
-            if eii_decl.impl_unsafe {
-                self.word(",");
-                self.space();
-                self.word("unsafe");
-            }
-            self.word(")]");
-            self.hardbreak();
-        }
         let (kw, has_bang) = if macro_def.macro_rules {
             ("macro_rules", true)
         } else {
@@ -1053,8 +1029,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
 
             /* Other */
             token::DocComment(comment_kind, attr_style, data) => {
-                doc_comment_to_string(DocFragmentKind::Sugared(comment_kind), attr_style, data)
+                doc_comment_to_string(comment_kind, attr_style, data).into()
-                    .into()
             }
             token::Eof => "<eof>".into(),
         }
@@ -1961,8 +1936,7 @@ impl<'a> State<'a> {
     }
 
     fn print_lifetime(&mut self, lifetime: ast::Lifetime) {
-        self.word(lifetime.ident.name.to_string());
+        self.print_name(lifetime.ident.name)
-        self.ann_post(lifetime.ident)
     }
 
     fn print_lifetime_bounds(&mut self, bounds: &ast::GenericBounds) {
@@ -2174,15 +2148,6 @@ impl<'a> State<'a> {
 
     fn print_meta_item(&mut self, item: &ast::MetaItem) {
         let ib = self.ibox(INDENT_UNIT);
-
-        match item.unsafety {
-            ast::Safety::Unsafe(_) => {
-                self.word("unsafe");
-                self.popen();
-            }
-            ast::Safety::Default | ast::Safety::Safe(_) => {}
-        }
-
         match &item.kind {
             ast::MetaItemKind::Word => self.print_path(&item.path, false, 0),
             ast::MetaItemKind::NameValue(value) => {
@@ -2198,12 +2163,6 @@ impl<'a> State<'a> {
                 self.pclose();
             }
         }
-
-        match item.unsafety {
-            ast::Safety::Unsafe(_) => self.pclose(),
-            ast::Safety::Default | ast::Safety::Safe(_) => {}
-        }
-
         self.end(ib);
     }
 

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -818,15 +818,10 @@ impl<'a> State<'a> {
                 );
                 self.word("?")
             }
-            ast::ExprKind::TryBlock(blk, opt_ty) => {
+            ast::ExprKind::TryBlock(blk) => {
                 let cb = self.cbox(0);
                 let ib = self.ibox(0);
                 self.word_nbsp("try");
-                if let Some(ty) = opt_ty {
-                    self.word_nbsp("bikeshed");
-                    self.print_type(ty);
-                    self.space();
-                }
                 self.print_block_with_attrs(blk, attrs, cb, ib)
             }
             ast::ExprKind::UnsafeBinderCast(kind, expr, ty) => {

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -1,6 +1,6 @@
 use ast::StaticItem;
 use itertools::{Itertools, Position};
-use rustc_ast::{self as ast, EiiImpl, ModKind, Safety, TraitAlias};
+use rustc_ast::{self as ast, ModKind, TraitAlias};
 use rustc_span::Ident;
 
 use crate::pp::BoxMarker;
@@ -51,7 +51,7 @@ impl<'a> State<'a> {
                 expr.as_deref(),
                 vis,
                 *safety,
-                ast::Defaultness::Implicit,
+                ast::Defaultness::Final,
                 define_opaque.as_deref(),
             ),
             ast::ForeignItemKind::TyAlias(box ast::TyAlias {
@@ -201,27 +201,16 @@ impl<'a> State<'a> {
                     body.as_deref(),
                     &item.vis,
                     ast::Safety::Default,
-                    ast::Defaultness::Implicit,
+                    ast::Defaultness::Final,
                     define_opaque.as_deref(),
                 );
             }
-            ast::ItemKind::ConstBlock(ast::ConstBlockItem { id: _, span: _, block }) => {
-                let ib = self.ibox(INDENT_UNIT);
-                self.word("const");
-                self.nbsp();
-                {
-                    let cb = self.cbox(0);
-                    let ib = self.ibox(0);
-                    self.print_block_with_attrs(block, &[], cb, ib);
-                }
-                self.end(ib);
-            }
             ast::ItemKind::Const(box ast::ConstItem {
                 defaultness,
                 ident,
                 generics,
                 ty,
-                rhs_kind,
+                rhs,
                 define_opaque,
             }) => {
                 self.print_item_const(
@@ -229,7 +218,7 @@ impl<'a> State<'a> {
                     None,
                     generics,
                     ty,
-                    rhs_kind.expr(),
+                    rhs.as_ref().map(|ct| ct.expr()),
                     &item.vis,
                     ast::Safety::Default,
                     *defaultness,
@@ -573,7 +562,7 @@ impl<'a> State<'a> {
                 ident,
                 generics,
                 ty,
-                rhs_kind,
+                rhs,
                 define_opaque,
             }) => {
                 self.print_item_const(
@@ -581,7 +570,7 @@ impl<'a> State<'a> {
                     None,
                     generics,
                     ty,
-                    rhs_kind.expr(),
+                    rhs.as_ref().map(|ct| ct.expr()),
                     vis,
                     ast::Safety::Default,
                     *defaultness,
@@ -682,25 +671,10 @@ impl<'a> State<'a> {
     }
 
     fn print_fn_full(&mut self, vis: &ast::Visibility, attrs: &[ast::Attribute], func: &ast::Fn) {
-        let ast::Fn { defaultness, ident, generics, sig, contract, body, define_opaque, eii_impls } =
+        let ast::Fn { defaultness, ident, generics, sig, contract, body, define_opaque } = func;
-            func;
 
         self.print_define_opaques(define_opaque.as_deref());
 
-        for EiiImpl { eii_macro_path, impl_safety, .. } in eii_impls {
-            self.word("#[");
-            if let Safety::Unsafe(..) = impl_safety {
-                self.word("unsafe");
-                self.popen();
-            }
-            self.print_path(eii_macro_path, false, 0);
-            if let Safety::Unsafe(..) = impl_safety {
-                self.pclose();
-            }
-            self.word("]");
-            self.hardbreak();
-        }
-
         let body_cb_ib = body.as_ref().map(|body| (body, self.head("")));
 
         self.print_visibility(vis);

compiler/rustc_attr_parsing/Cargo.toml

@@ -8,9 +8,9 @@ edition = "2024"
 rustc_abi = { path = "../rustc_abi" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
-rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
+rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_macros = { path = "../rustc_macros" }

compiler/rustc_attr_parsing/messages.ftl

@@ -0,0 +1,268 @@
+attr_parsing_as_needed_compatibility =
+    linking modifier `as-needed` is only compatible with `dylib`, `framework` and `raw-dylib` linking kinds
+
+attr_parsing_bundle_needs_static =
+    linking modifier `bundle` is only compatible with `static` linking kind
+
+attr_parsing_cfg_attr_bad_delim = wrong `cfg_attr` delimiters
+
+attr_parsing_cfg_predicate_identifier =
+    `cfg` predicate key must be an identifier
+
+attr_parsing_deprecated_item_suggestion =
+    suggestions on deprecated items are unstable
+    .help = add `#![feature(deprecated_suggestion)]` to the crate root
+    .note = see #94785 for more details
+
+attr_parsing_empty_attribute =
+    unused attribute
+    .suggestion = {$valid_without_list ->
+        [true] remove these parentheses
+        *[other] remove this attribute
+    }
+    .note = {$valid_without_list ->
+        [true] using `{$attr_path}` with an empty list is equivalent to not using a list at all
+        *[other] using `{$attr_path}` with an empty list has no effect
+    }
+
+
+attr_parsing_empty_confusables =
+    expected at least one confusable name
+attr_parsing_empty_link_name =
+    link name must not be empty
+    .label = empty link name
+
+attr_parsing_expected_one_cfg_pattern =
+    expected 1 cfg-pattern
+
+attr_parsing_expected_single_version_literal =
+    expected single version literal
+
+attr_parsing_expected_version_literal =
+    expected a version literal
+
+attr_parsing_expects_feature_list =
+    `{$name}` expects a list of feature names
+
+attr_parsing_expects_features =
+    `{$name}` expects feature names
+
+attr_parsing_ill_formed_attribute_input = {$num_suggestions ->
+        [1] attribute must be of the form {$suggestions}
+        *[other] valid forms for the attribute are {$suggestions}
+    }
+
+attr_parsing_import_name_type_raw =
+    import name type can only be used with link kind `raw-dylib`
+
+attr_parsing_import_name_type_x86 =
+    import name type is only supported on x86
+
+attr_parsing_incompatible_wasm_link =
+    `wasm_import_module` is incompatible with other arguments in `#[link]` attributes
+
+attr_parsing_incorrect_repr_format_align_one_arg =
+    incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
+
+attr_parsing_incorrect_repr_format_expect_literal_integer =
+    incorrect `repr(align)` attribute format: `align` expects a literal integer as argument
+
+attr_parsing_incorrect_repr_format_generic =
+    incorrect `repr({$repr_arg})` attribute format
+    .suggestion = use parentheses instead
+
+attr_parsing_incorrect_repr_format_packed_expect_integer =
+    incorrect `repr(packed)` attribute format: `packed` expects a literal integer as argument
+
+attr_parsing_incorrect_repr_format_packed_one_or_zero_arg =
+    incorrect `repr(packed)` attribute format: `packed` takes exactly one parenthesized argument, or no parentheses at all
+
+attr_parsing_invalid_alignment_value =
+    invalid alignment value: {$error_part}
+
+attr_parsing_invalid_attr_unsafe = `{$name}` is not an unsafe attribute
+    .label = this is not an unsafe attribute
+    .suggestion = remove the `unsafe(...)`
+    .note = extraneous unsafe is not allowed in attributes
+
+attr_parsing_invalid_issue_string =
+    `issue` must be a non-zero numeric string or "none"
+    .must_not_be_zero = `issue` must not be "0", use "none" instead
+    .empty = cannot parse integer from empty string
+    .invalid_digit = invalid digit found in string
+    .pos_overflow = number too large to fit in target type
+    .neg_overflow = number too small to fit in target type
+
+attr_parsing_invalid_link_modifier =
+    invalid linking modifier syntax, expected '+' or '-' prefix before one of: bundle, verbatim, whole-archive, as-needed
+
+attr_parsing_invalid_meta_item = expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found {$descr}
+    .remove_neg_sugg = negative numbers are not literals, try removing the `-` sign
+    .quote_ident_sugg = surround the identifier with quotation marks to make it into a string literal
+
+attr_parsing_invalid_predicate =
+    invalid predicate `{$predicate}`
+
+attr_parsing_invalid_repr_align_need_arg =
+    invalid `repr(align)` attribute: `align` needs an argument
+    .suggestion = supply an argument here
+
+attr_parsing_invalid_repr_generic =
+    invalid `repr({$repr_arg})` attribute: {$error_part}
+
+attr_parsing_invalid_repr_hint_no_paren =
+    invalid representation hint: `{$name}` does not take a parenthesized argument list
+
+attr_parsing_invalid_repr_hint_no_value =
+    invalid representation hint: `{$name}` does not take a value
+
+attr_parsing_invalid_since =
+    'since' must be a Rust version number, such as "1.31.0"
+
+attr_parsing_invalid_style = {$is_used_as_inner ->
+        [false] crate-level attribute should be an inner attribute: add an exclamation mark: `#![{$name}]`
+        *[other] the `#![{$name}]` attribute can only be used at the crate root
+    }
+    .note = This attribute does not have an `!`, which means it is applied to this {$target}
+
+attr_parsing_invalid_target = `#[{$name}]` attribute cannot be used on {$target}
+    .help = `#[{$name}]` can {$only}be applied to {$applied}
+    .suggestion = remove the attribute
+attr_parsing_invalid_target_lint = `#[{$name}]` attribute cannot be used on {$target}
+    .warn = {-attr_parsing_previously_accepted}
+    .help = `#[{$name}]` can {$only}be applied to {$applied}
+    .suggestion = remove the attribute
+
+attr_parsing_limit_invalid =
+    `limit` must be a non-negative integer
+    .label = {$error_str}
+attr_parsing_link_arg_unstable =
+    link kind `link-arg` is unstable
+
+attr_parsing_link_cfg_unstable =
+    link cfg is unstable
+
+attr_parsing_link_framework_apple =
+    link kind `framework` is only supported on Apple targets
+
+attr_parsing_link_ordinal_out_of_range = ordinal value in `link_ordinal` is too large: `{$ordinal}`
+    .note = the value may not exceed `u16::MAX`
+
+attr_parsing_link_requires_name =
+    `#[link]` attribute requires a `name = "string"` argument
+    .label = missing `name` argument
+
+attr_parsing_meta_bad_delim = wrong meta list delimiters
+attr_parsing_meta_bad_delim_suggestion = the delimiters should be `(` and `)`
+
+attr_parsing_missing_feature =
+    missing 'feature'
+
+attr_parsing_missing_issue =
+    missing 'issue'
+
+attr_parsing_missing_note =
+    missing 'note'
+
+attr_parsing_missing_since =
+    missing 'since'
+
+attr_parsing_multiple_modifiers =
+    multiple `{$modifier}` modifiers in a single `modifiers` argument
+
+attr_parsing_multiple_stability_levels =
+    multiple stability levels
+
+attr_parsing_naked_functions_incompatible_attribute =
+    attribute incompatible with `#[unsafe(naked)]`
+    .label = the `{$attr}` attribute is incompatible with `#[unsafe(naked)]`
+    .naked_attribute = function marked with `#[unsafe(naked)]` here
+
+attr_parsing_non_ident_feature =
+    'feature' is not an identifier
+
+attr_parsing_null_on_export = `export_name` may not contain null characters
+
+attr_parsing_null_on_link_section = `link_section` may not contain null characters
+
+attr_parsing_null_on_objc_class = `objc::class!` may not contain null characters
+
+attr_parsing_null_on_objc_selector = `objc::selector!` may not contain null characters
+
+attr_parsing_objc_class_expected_string_literal = `objc::class!` expected a string literal
+
+attr_parsing_objc_selector_expected_string_literal = `objc::selector!` expected a string literal
+
+attr_parsing_raw_dylib_elf_unstable =
+    link kind `raw-dylib` is unstable on ELF platforms
+
+attr_parsing_raw_dylib_no_nul =
+    link name must not contain NUL characters if link kind is `raw-dylib`
+
+attr_parsing_raw_dylib_only_windows =
+    link kind `raw-dylib` is only supported on Windows targets
+
+attr_parsing_repr_ident =
+    meta item in `repr` must be an identifier
+
+attr_parsing_rustc_allowed_unstable_pairing =
+    `rustc_allowed_through_unstable_modules` attribute must be paired with a `stable` attribute
+
+attr_parsing_rustc_promotable_pairing =
+    `rustc_promotable` attribute must be paired with either a `rustc_const_unstable` or a `rustc_const_stable` attribute
+
+attr_parsing_soft_no_args =
+    `soft` should not have any arguments
+
+attr_parsing_stability_outside_std = stability attributes may not be used outside of the standard library
+
+attr_parsing_suffixed_literal_in_attribute = suffixed literals are not allowed in attributes
+    .help = instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), use an unsuffixed version (`1`, `1.0`, etc.)
+
+attr_parsing_unknown_meta_item =
+    unknown meta item '{$item}'
+    .label = expected one of {$expected}
+
+attr_parsing_unknown_version_literal =
+    unknown version literal format, assuming it refers to a future version
+
+attr_parsing_unrecognized_repr_hint =
+    unrecognized representation hint
+    .help = valid reprs are `Rust` (default), `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
+    .note = for more information, visit <https://doc.rust-lang.org/reference/type-layout.html?highlight=repr#representations>
+
+attr_parsing_unsafe_attr_outside_unsafe = unsafe attribute used without unsafe
+    .label = usage of unsafe attribute
+attr_parsing_unsafe_attr_outside_unsafe_suggestion = wrap the attribute in `unsafe(...)`
+
+attr_parsing_unstable_cfg_target_compact =
+    compact `cfg(target(..))` is experimental and subject to change
+
+attr_parsing_unstable_feature_bound_incompatible_stability = item annotated with `#[unstable_feature_bound]` should not be stable
+    .help = If this item is meant to be stable, do not use any functions annotated with `#[unstable_feature_bound]`. Otherwise, mark this item as unstable with `#[unstable]`
+
+attr_parsing_unsupported_literal_cfg_boolean =
+    literal in `cfg` predicate value must be a boolean
+attr_parsing_unsupported_literal_cfg_string =
+    literal in `cfg` predicate value must be a string
+attr_parsing_unsupported_literal_generic =
+    unsupported literal
+attr_parsing_unsupported_literal_suggestion =
+    consider removing the prefix
+
+attr_parsing_unused_duplicate =
+    unused attribute
+    .suggestion = remove this attribute
+    .note = attribute also specified here
+    .warn = {-attr_parsing_previously_accepted}
+
+attr_parsing_unused_multiple =
+    multiple `{$name}` attributes
+    .suggestion = remove this attribute
+    .note = attribute also specified here
+
+-attr_parsing_previously_accepted =
+    this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+
+attr_parsing_whole_archive_needs_static =
+    linking modifier `whole-archive` is only compatible with `static` linking kind

compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs

@@ -17,9 +17,9 @@ impl<S: Stage> CombineAttributeParser<S> for AllowInternalUnstableParser {
     ]);
     const TEMPLATE: AttributeTemplate = template!(Word, List: &["feat1, feat2, ..."]);
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
     ) -> impl IntoIterator<Item = Self::Item> {
         parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
             .into_iter()
@@ -29,7 +29,7 @@ impl<S: Stage> CombineAttributeParser<S> for AllowInternalUnstableParser {
 
 pub(crate) struct UnstableFeatureBoundParser;
 impl<S: Stage> CombineAttributeParser<S> for UnstableFeatureBoundParser {
-    const PATH: &[rustc_span::Symbol] = &[sym::unstable_feature_bound];
+    const PATH: &'static [rustc_span::Symbol] = &[sym::unstable_feature_bound];
     type Item = (Symbol, Span);
     const CONVERT: ConvertFn<Self::Item> = |items, _| AttributeKind::UnstableFeatureBound(items);
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
@@ -39,9 +39,9 @@ impl<S: Stage> CombineAttributeParser<S> for UnstableFeatureBoundParser {
     ]);
     const TEMPLATE: AttributeTemplate = template!(Word, List: &["feat1, feat2, ..."]);
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
     ) -> impl IntoIterator<Item = Self::Item> {
         if !cx.features().staged_api() {
             cx.emit_err(session_diagnostics::StabilityOutsideStd { span: cx.attr_span });
@@ -57,26 +57,27 @@ impl<S: Stage> CombineAttributeParser<S> for AllowConstFnUnstableParser {
     const PATH: &[Symbol] = &[sym::rustc_allow_const_fn_unstable];
     type Item = Symbol;
     const CONVERT: ConvertFn<Self::Item> =
-        |items, first_span| AttributeKind::RustcAllowConstFnUnstable(items, first_span);
+        |items, first_span| AttributeKind::AllowConstFnUnstable(items, first_span);
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
+        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
     ]);
     const TEMPLATE: AttributeTemplate = template!(Word, List: &["feat1, feat2, ..."]);
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item> {
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
         parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
     }
 }
 
 fn parse_unstable<S: Stage>(
     cx: &AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &ArgParser<'_>,
     symbol: Symbol,
 ) -> impl IntoIterator<Item = Symbol> {
     let mut res = Vec::new();

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -2,18 +2,16 @@ use std::convert::identity;
 
 use rustc_ast::token::Delimiter;
 use rustc_ast::tokenstream::DelimSpan;
-use rustc_ast::{AttrItem, Attribute, CRATE_NODE_ID, LitKind, ast, token};
+use rustc_ast::{AttrItem, Attribute, CRATE_NODE_ID, LitKind, NodeId, ast, token};
-use rustc_errors::{Applicability, PResult, msg};
+use rustc_errors::{Applicability, PResult};
-use rustc_feature::{
+use rustc_feature::{AttrSuggestionStyle, AttributeTemplate, Features, template};
-    AttrSuggestionStyle, AttributeTemplate, Features, GatedCfg, find_gated_cfg, template,
-};
 use rustc_hir::attrs::CfgEntry;
-use rustc_hir::lints::AttributeLintKind;
+use rustc_hir::{AttrPath, RustcVersion};
-use rustc_hir::{AttrPath, RustcVersion, Target};
+use rustc_parse::parser::{ForceCollect, Parser};
-use rustc_parse::parser::{ForceCollect, Parser, Recovery};
 use rustc_parse::{exp, parse_in};
 use rustc_session::Session;
 use rustc_session::config::ExpectedValues;
+use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::UNEXPECTED_CFGS;
 use rustc_session::parse::{ParseSess, feature_err};
 use rustc_span::{ErrorGuaranteed, Span, Symbol, sym};
@@ -25,7 +23,10 @@ use crate::session_diagnostics::{
     AttributeParseError, AttributeParseErrorReason, CfgAttrBadDelim, MetaBadDelimSugg,
     ParsedDescription,
 };
-use crate::{AttributeParser, parse_version, session_diagnostics};
+use crate::{
+    AttributeParser, CfgMatchesLintEmitter, fluent_generated, parse_version, session_diagnostics,
+    try_gate_cfg,
+};
 
 pub const CFG_TEMPLATE: AttributeTemplate = template!(
     List: &["predicate"],
@@ -37,12 +38,12 @@ const CFG_ATTR_TEMPLATE: AttributeTemplate = template!(
     "https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute"
 );
 
-pub fn parse_cfg<S: Stage>(
+pub fn parse_cfg<'c, S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &'c mut AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &'c ArgParser<'_>,
 ) -> Option<CfgEntry> {
     let ArgParser::List(list) = args else {
-        cx.expected_list(cx.attr_span, args);
+        cx.expected_list(cx.attr_span);
         return None;
     };
     let Some(single) = list.single() else {
@@ -54,7 +55,7 @@ pub fn parse_cfg<S: Stage>(
 
 pub fn parse_cfg_entry<S: Stage>(
     cx: &mut AcceptContext<'_, '_, S>,
-    item: &MetaItemOrLitParser,
+    item: &MetaItemOrLitParser<'_>,
 ) -> Result<CfgEntry, ErrorGuaranteed> {
     Ok(match item {
         MetaItemOrLitParser::MetaItemParser(meta) => match meta.args() {
@@ -94,12 +95,13 @@ pub fn parse_cfg_entry<S: Stage>(
             LitKind::Bool(b) => CfgEntry::Bool(b, lit.span),
             _ => return Err(cx.expected_identifier(lit.span)),
         },
+        MetaItemOrLitParser::Err(_, err) => return Err(*err),
     })
 }
 
 fn parse_cfg_entry_version<S: Stage>(
     cx: &mut AcceptContext<'_, '_, S>,
-    list: &MetaItemListParser,
+    list: &MetaItemListParser<'_>,
     meta_span: Span,
 ) -> Result<CfgEntry, ErrorGuaranteed> {
     try_gate_cfg(sym::version, meta_span, cx.sess(), cx.features_option());
@@ -131,7 +133,7 @@ fn parse_cfg_entry_version<S: Stage>(
 
 fn parse_cfg_entry_target<S: Stage>(
     cx: &mut AcceptContext<'_, '_, S>,
-    list: &MetaItemListParser,
+    list: &MetaItemListParser<'_>,
     meta_span: Span,
 ) -> Result<CfgEntry, ErrorGuaranteed> {
     if let Some(features) = cx.features_option()
@@ -141,7 +143,7 @@ fn parse_cfg_entry_target<S: Stage>(
             cx.sess(),
             sym::cfg_target_compact,
             meta_span,
-            msg!("compact `cfg(target(..))` is experimental and subject to change"),
+            fluent_generated::attr_parsing_unstable_cfg_target_compact,
         )
         .emit();
     }
@@ -172,7 +174,7 @@ fn parse_cfg_entry_target<S: Stage>(
     Ok(CfgEntry::All(result, list.span))
 }
 
-pub(crate) fn parse_name_value<S: Stage>(
+fn parse_name_value<S: Stage>(
     name: Symbol,
     name_span: Span,
     value: Option<&NameValueParser>,
@@ -193,46 +195,43 @@ pub(crate) fn parse_name_value<S: Stage>(
         }
     };
 
-    match cx.sess.psess.check_config.expecteds.get(&name) {
+    Ok(CfgEntry::NameValue { name, name_span, value, span })
-        Some(ExpectedValues::Some(values)) if !values.contains(&value.map(|(v, _)| v)) => cx
-            .emit_lint(
-                UNEXPECTED_CFGS,
-                AttributeLintKind::UnexpectedCfgValue((name, name_span), value),
-                span,
-            ),
-        None if cx.sess.psess.check_config.exhaustive_names => cx.emit_lint(
-            UNEXPECTED_CFGS,
-            AttributeLintKind::UnexpectedCfgName((name, name_span), value),
-            span,
-        ),
-        _ => { /* not unexpected */ }
-    }
-
-    Ok(CfgEntry::NameValue { name, value: value.map(|(v, _)| v), span })
 }
 
-pub fn eval_config_entry(sess: &Session, cfg_entry: &CfgEntry) -> EvalConfigResult {
+pub fn eval_config_entry(
+    sess: &Session,
+    cfg_entry: &CfgEntry,
+    id: NodeId,
+    emit_lints: ShouldEmit,
+) -> EvalConfigResult {
     match cfg_entry {
         CfgEntry::All(subs, ..) => {
+            let mut all = None;
             for sub in subs {
-                let res = eval_config_entry(sess, sub);
+                let res = eval_config_entry(sess, sub, id, emit_lints);
+                // We cannot short-circuit because `eval_config_entry` emits some lints
                 if !res.as_bool() {
-                    return res;
+                    all.get_or_insert(res);
                 }
             }
-            EvalConfigResult::True
+            all.unwrap_or_else(|| EvalConfigResult::True)
         }
         CfgEntry::Any(subs, span) => {
+            let mut any = None;
             for sub in subs {
-                let res = eval_config_entry(sess, sub);
+                let res = eval_config_entry(sess, sub, id, emit_lints);
+                // We cannot short-circuit because `eval_config_entry` emits some lints
                 if res.as_bool() {
-                    return res;
+                    any.get_or_insert(res);
                 }
             }
-            EvalConfigResult::False { reason: cfg_entry.clone(), reason_span: *span }
+            any.unwrap_or_else(|| EvalConfigResult::False {
+                reason: cfg_entry.clone(),
+                reason_span: *span,
+            })
         }
         CfgEntry::Not(sub, span) => {
-            if eval_config_entry(sess, sub).as_bool() {
+            if eval_config_entry(sess, sub, id, emit_lints).as_bool() {
                 EvalConfigResult::False { reason: cfg_entry.clone(), reason_span: *span }
             } else {
                 EvalConfigResult::True
@@ -245,8 +244,32 @@ pub fn eval_config_entry(sess: &Session, cfg_entry: &CfgEntry) -> EvalConfigResu
                 EvalConfigResult::False { reason: cfg_entry.clone(), reason_span: *span }
             }
         }
-        CfgEntry::NameValue { name, value, span } => {
+        CfgEntry::NameValue { name, name_span, value, span } => {
-            if sess.psess.config.contains(&(*name, *value)) {
+            if let ShouldEmit::ErrorsAndLints = emit_lints {
+                match sess.psess.check_config.expecteds.get(name) {
+                    Some(ExpectedValues::Some(values))
+                        if !values.contains(&value.map(|(v, _)| v)) =>
+                    {
+                        id.emit_span_lint(
+                            sess,
+                            UNEXPECTED_CFGS,
+                            *span,
+                            BuiltinLintDiag::UnexpectedCfgValue((*name, *name_span), *value),
+                        );
+                    }
+                    None if sess.psess.check_config.exhaustive_names => {
+                        id.emit_span_lint(
+                            sess,
+                            UNEXPECTED_CFGS,
+                            *span,
+                            BuiltinLintDiag::UnexpectedCfgName((*name, *name_span), *value),
+                        );
+                    }
+                    _ => { /* not unexpected */ }
+                }
+            }
+
+            if sess.psess.config.contains(&(*name, value.map(|(v, _)| v))) {
                 EvalConfigResult::True
             } else {
                 EvalConfigResult::False { reason: cfg_entry.clone(), reason_span: *span }
@@ -293,9 +316,11 @@ pub fn parse_cfg_attr(
     sess: &Session,
     features: Option<&Features>,
 ) -> Option<(CfgEntry, Vec<(AttrItem, Span)>)> {
-    match cfg_attr.get_normal_item().args.unparsed_ref().unwrap() {
+    match cfg_attr.get_normal_item().args {
-        ast::AttrArgs::Delimited(ast::DelimArgs { dspan, delim, tokens }) if !tokens.is_empty() => {
+        ast::AttrArgs::Delimited(ast::DelimArgs { dspan, delim, ref tokens })
-            check_cfg_attr_bad_delim(&sess.psess, *dspan, *delim);
+            if !tokens.is_empty() =>
+        {
+            check_cfg_attr_bad_delim(&sess.psess, dspan, delim);
             match parse_in(&sess.psess, tokens.clone(), "`cfg_attr` input", |p| {
                 parse_cfg_attr_internal(p, sess, features, cfg_attr)
             }) {
@@ -319,7 +344,7 @@ pub fn parse_cfg_attr(
         }
         _ => {
             let (span, reason) = if let ast::AttrArgs::Delimited(ast::DelimArgs { dspan, .. }) =
-                cfg_attr.get_normal_item().args.unparsed_ref()?
+                cfg_attr.get_normal_item().args
             {
                 (dspan.entire(), AttributeParseErrorReason::ExpectedAtLeastOneArgument)
             } else {
@@ -360,10 +385,7 @@ fn parse_cfg_attr_internal<'a>(
 ) -> PResult<'a, (CfgEntry, Vec<(ast::AttrItem, Span)>)> {
     // Parse cfg predicate
     let pred_start = parser.token.span;
-    let meta = MetaItemOrLitParser::parse_single(
+    let meta = MetaItemOrLitParser::parse_single(parser, ShouldEmit::ErrorsAndLints)?;
-        parser,
-        ShouldEmit::ErrorsAndLints { recovery: Recovery::Allowed },
-    )?;
     let pred_span = pred_start.with_hi(parser.token.span.hi());
 
     let cfg_predicate = AttributeParser::parse_single_args(
@@ -371,14 +393,19 @@ fn parse_cfg_attr_internal<'a>(
         attribute.span,
         attribute.get_normal_item().span(),
         attribute.style,
-        AttrPath { segments: attribute.path().into_boxed_slice(), span: attribute.span },
+        AttrPath {
+            segments: attribute
+                .ident_path()
+                .expect("cfg_attr is not a doc comment")
+                .into_boxed_slice(),
+            span: attribute.span,
+        },
         Some(attribute.get_normal_item().unsafety),
         ParsedDescription::Attribute,
         pred_span,
         CRATE_NODE_ID,
-        Target::Crate,
         features,
-        ShouldEmit::ErrorsAndLints { recovery: Recovery::Allowed },
+        ShouldEmit::ErrorsAndLints,
         &meta,
         parse_cfg_entry,
         &CFG_ATTR_TEMPLATE,
@@ -407,18 +434,3 @@ fn parse_cfg_attr_internal<'a>(
 
     Ok((cfg_predicate, expanded_attrs))
 }
-
-fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, features: Option<&Features>) {
-    let gate = find_gated_cfg(|sym| sym == name);
-    if let (Some(feats), Some(gated_cfg)) = (features, gate) {
-        gate_cfg(gated_cfg, span, sess, feats);
-    }
-}
-
-fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) {
-    let (cfg, feature, has_feature) = gated_cfg;
-    if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
-        let explain = format!("`cfg({cfg})` is experimental and subject to change");
-        feature_err(sess, *feature, cfg_span, explain).emit();
-    }
-}

compiler/rustc_attr_parsing/src/attributes/cfg_old.rs

@@ -0,0 +1,250 @@
+use rustc_ast::{LitKind, MetaItem, MetaItemInner, MetaItemKind, MetaItemLit, NodeId};
+use rustc_ast_pretty::pprust;
+use rustc_feature::{Features, GatedCfg, find_gated_cfg};
+use rustc_hir::RustcVersion;
+use rustc_session::Session;
+use rustc_session::config::ExpectedValues;
+use rustc_session::lint::builtin::UNEXPECTED_CFGS;
+use rustc_session::lint::{BuiltinLintDiag, Lint};
+use rustc_session::parse::feature_err;
+use rustc_span::{Span, Symbol, sym};
+
+use crate::session_diagnostics::{self, UnsupportedLiteralReason};
+use crate::{fluent_generated, parse_version};
+
+/// Emitter of a builtin lint from `cfg_matches`.
+///
+/// Used to support emitting a lint (currently on check-cfg), either:
+///  - as an early buffered lint (in `rustc`)
+///  - or has a "normal" lint from HIR (in `rustdoc`)
+pub trait CfgMatchesLintEmitter {
+    fn emit_span_lint(&self, sess: &Session, lint: &'static Lint, sp: Span, diag: BuiltinLintDiag);
+}
+
+impl CfgMatchesLintEmitter for NodeId {
+    fn emit_span_lint(&self, sess: &Session, lint: &'static Lint, sp: Span, diag: BuiltinLintDiag) {
+        sess.psess.buffer_lint(lint, sp, *self, diag);
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct Condition {
+    pub name: Symbol,
+    pub name_span: Span,
+    pub value: Option<Symbol>,
+    pub value_span: Option<Span>,
+    pub span: Span,
+}
+
+/// Tests if a cfg-pattern matches the cfg set
+pub fn cfg_matches(
+    cfg: &MetaItemInner,
+    sess: &Session,
+    lint_emitter: impl CfgMatchesLintEmitter,
+    features: Option<&Features>,
+) -> bool {
+    eval_condition(cfg, sess, features, &mut |cfg| {
+        try_gate_cfg(cfg.name, cfg.span, sess, features);
+        match sess.psess.check_config.expecteds.get(&cfg.name) {
+            Some(ExpectedValues::Some(values)) if !values.contains(&cfg.value) => {
+                lint_emitter.emit_span_lint(
+                    sess,
+                    UNEXPECTED_CFGS,
+                    cfg.span,
+                    BuiltinLintDiag::UnexpectedCfgValue(
+                        (cfg.name, cfg.name_span),
+                        cfg.value.map(|v| (v, cfg.value_span.unwrap())),
+                    ),
+                );
+            }
+            None if sess.psess.check_config.exhaustive_names => {
+                lint_emitter.emit_span_lint(
+                    sess,
+                    UNEXPECTED_CFGS,
+                    cfg.span,
+                    BuiltinLintDiag::UnexpectedCfgName(
+                        (cfg.name, cfg.name_span),
+                        cfg.value.map(|v| (v, cfg.value_span.unwrap())),
+                    ),
+                );
+            }
+            _ => { /* not unexpected */ }
+        }
+        sess.psess.config.contains(&(cfg.name, cfg.value))
+    })
+}
+
+pub fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, features: Option<&Features>) {
+    let gate = find_gated_cfg(|sym| sym == name);
+    if let (Some(feats), Some(gated_cfg)) = (features, gate) {
+        gate_cfg(gated_cfg, span, sess, feats);
+    }
+}
+
+#[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
+fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) {
+    let (cfg, feature, has_feature) = gated_cfg;
+    if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
+        let explain = format!("`cfg({cfg})` is experimental and subject to change");
+        feature_err(sess, *feature, cfg_span, explain).emit();
+    }
+}
+
+/// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to
+/// evaluate individual items.
+pub fn eval_condition(
+    cfg: &MetaItemInner,
+    sess: &Session,
+    features: Option<&Features>,
+    eval: &mut impl FnMut(Condition) -> bool,
+) -> bool {
+    let dcx = sess.dcx();
+
+    let cfg = match cfg {
+        MetaItemInner::MetaItem(meta_item) => meta_item,
+        MetaItemInner::Lit(MetaItemLit { kind: LitKind::Bool(b), .. }) => {
+            return *b;
+        }
+        _ => {
+            dcx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: cfg.span(),
+                reason: UnsupportedLiteralReason::CfgBoolean,
+                is_bytestr: false,
+                start_point_span: sess.source_map().start_point(cfg.span()),
+            });
+            return false;
+        }
+    };
+
+    match &cfg.kind {
+        MetaItemKind::List(mis) if cfg.has_name(sym::version) => {
+            try_gate_cfg(sym::version, cfg.span, sess, features);
+            let (min_version, span) = match &mis[..] {
+                [MetaItemInner::Lit(MetaItemLit { kind: LitKind::Str(sym, ..), span, .. })] => {
+                    (sym, span)
+                }
+                [
+                    MetaItemInner::Lit(MetaItemLit { span, .. })
+                    | MetaItemInner::MetaItem(MetaItem { span, .. }),
+                ] => {
+                    dcx.emit_err(session_diagnostics::ExpectedVersionLiteral { span: *span });
+                    return false;
+                }
+                [..] => {
+                    dcx.emit_err(session_diagnostics::ExpectedSingleVersionLiteral {
+                        span: cfg.span,
+                    });
+                    return false;
+                }
+            };
+            let Some(min_version) = parse_version(*min_version) else {
+                dcx.emit_warn(session_diagnostics::UnknownVersionLiteral { span: *span });
+                return false;
+            };
+
+            // See https://github.com/rust-lang/rust/issues/64796#issuecomment-640851454 for details
+            if sess.psess.assume_incomplete_release {
+                RustcVersion::current_overridable() > min_version
+            } else {
+                RustcVersion::current_overridable() >= min_version
+            }
+        }
+        MetaItemKind::List(mis) => {
+            for mi in mis.iter() {
+                if mi.meta_item_or_bool().is_none() {
+                    dcx.emit_err(session_diagnostics::UnsupportedLiteral {
+                        span: mi.span(),
+                        reason: UnsupportedLiteralReason::Generic,
+                        is_bytestr: false,
+                        start_point_span: sess.source_map().start_point(mi.span()),
+                    });
+                    return false;
+                }
+            }
+
+            // The unwraps below may look dangerous, but we've already asserted
+            // that they won't fail with the loop above.
+            match cfg.name() {
+                Some(sym::any) => mis
+                    .iter()
+                    // We don't use any() here, because we want to evaluate all cfg condition
+                    // as eval_condition can (and does) extra checks
+                    .fold(false, |res, mi| res | eval_condition(mi, sess, features, eval)),
+                Some(sym::all) => mis
+                    .iter()
+                    // We don't use all() here, because we want to evaluate all cfg condition
+                    // as eval_condition can (and does) extra checks
+                    .fold(true, |res, mi| res & eval_condition(mi, sess, features, eval)),
+                Some(sym::not) => {
+                    let [mi] = mis.as_slice() else {
+                        dcx.emit_err(session_diagnostics::ExpectedOneCfgPattern { span: cfg.span });
+                        return false;
+                    };
+
+                    !eval_condition(mi, sess, features, eval)
+                }
+                Some(sym::target) => {
+                    if let Some(features) = features
+                        && !features.cfg_target_compact()
+                    {
+                        feature_err(
+                            sess,
+                            sym::cfg_target_compact,
+                            cfg.span,
+                            fluent_generated::attr_parsing_unstable_cfg_target_compact,
+                        )
+                        .emit();
+                    }
+
+                    mis.iter().fold(true, |res, mi| {
+                        let Some(mut mi) = mi.meta_item().cloned() else {
+                            dcx.emit_err(session_diagnostics::CfgPredicateIdentifier {
+                                span: mi.span(),
+                            });
+                            return false;
+                        };
+
+                        if let [seg, ..] = &mut mi.path.segments[..] {
+                            seg.ident.name = Symbol::intern(&format!("target_{}", seg.ident.name));
+                        }
+
+                        res & eval_condition(&MetaItemInner::MetaItem(mi), sess, features, eval)
+                    })
+                }
+                _ => {
+                    dcx.emit_err(session_diagnostics::InvalidPredicate {
+                        span: cfg.span,
+                        predicate: pprust::path_to_string(&cfg.path),
+                    });
+                    false
+                }
+            }
+        }
+        MetaItemKind::Word | MetaItemKind::NameValue(..)
+            if cfg.path.segments.len() != 1
+                || cfg.path.segments[0].ident.is_path_segment_keyword() =>
+        {
+            dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span });
+            true
+        }
+        MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
+            dcx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: lit.span,
+                reason: UnsupportedLiteralReason::CfgString,
+                is_bytestr: lit.kind.is_bytestr(),
+                start_point_span: sess.source_map().start_point(lit.span),
+            });
+            true
+        }
+        MetaItemKind::Word | MetaItemKind::NameValue(..) => {
+            let ident = cfg.ident().expect("multi-segment cfg predicate");
+            eval(Condition {
+                name: ident.name,
+                name_span: ident.span,
+                value: cfg.value_str(),
+                value_span: cfg.name_value_literal_span(),
+                span: cfg.span,
+            })
+        }
+    }
+}

compiler/rustc_attr_parsing/src/attributes/cfg_select.rs

@@ -1,35 +1,22 @@
 use rustc_ast::token::Token;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::{AttrStyle, NodeId, token};
-use rustc_data_structures::fx::FxHashMap;
 use rustc_feature::{AttributeTemplate, Features};
+use rustc_hir::AttrPath;
 use rustc_hir::attrs::CfgEntry;
-use rustc_hir::{AttrPath, Target};
 use rustc_parse::exp;
-use rustc_parse::parser::{Parser, Recovery};
+use rustc_parse::parser::Parser;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
+use rustc_span::{ErrorGuaranteed, Ident, Span};
-use rustc_session::lint::builtin::UNREACHABLE_CFG_SELECT_PREDICATES;
-use rustc_span::{ErrorGuaranteed, Span, Symbol, sym};
 
 use crate::parser::MetaItemOrLitParser;
 use crate::{AttributeParser, ParsedDescription, ShouldEmit, parse_cfg_entry};
 
-#[derive(Clone)]
 pub enum CfgSelectPredicate {
     Cfg(CfgEntry),
     Wildcard(Token),
 }
 
-impl CfgSelectPredicate {
-    fn span(&self) -> Span {
-        match self {
-            CfgSelectPredicate::Cfg(cfg_entry) => cfg_entry.span(),
-            CfgSelectPredicate::Wildcard(token) => token.span,
-        }
-    }
-}
-
 #[derive(Default)]
 pub struct CfgSelectBranches {
     /// All the conditional branches.
@@ -41,33 +28,6 @@ pub struct CfgSelectBranches {
     pub unreachable: Vec<(CfgSelectPredicate, TokenStream, Span)>,
 }
 
-impl CfgSelectBranches {
-    /// Removes the top-most branch for which `predicate` returns `true`,
-    /// or the wildcard if none of the reachable branches satisfied the predicate.
-    pub fn pop_first_match<F>(&mut self, predicate: F) -> Option<(TokenStream, Span)>
-    where
-        F: Fn(&CfgEntry) -> bool,
-    {
-        for (index, (cfg, _, _)) in self.reachable.iter().enumerate() {
-            if predicate(cfg) {
-                let matched = self.reachable.remove(index);
-                return Some((matched.1, matched.2));
-            }
-        }
-
-        self.wildcard.take().map(|(_, tts, span)| (tts, span))
-    }
-
-    /// Consume this value and iterate over all the `TokenStream`s that it stores.
-    pub fn into_iter_tts(self) -> impl Iterator<Item = (TokenStream, Span)> {
-        let it1 = self.reachable.into_iter().map(|(_, tts, span)| (tts, span));
-        let it2 = self.wildcard.into_iter().map(|(_, tts, span)| (tts, span));
-        let it3 = self.unreachable.into_iter().map(|(_, tts, span)| (tts, span));
-
-        it1.chain(it2).chain(it3)
-    }
-}
-
 pub fn parse_cfg_select(
     p: &mut Parser<'_>,
     sess: &Session,
@@ -91,26 +51,24 @@ pub fn parse_cfg_select(
                 }
             }
         } else {
-            let meta = MetaItemOrLitParser::parse_single(
+            let meta = MetaItemOrLitParser::parse_single(p, ShouldEmit::ErrorsAndLints)
-                p,
+                .map_err(|diag| diag.emit())?;
-                ShouldEmit::ErrorsAndLints { recovery: Recovery::Allowed },
-            )
-            .map_err(|diag| diag.emit())?;
             let cfg_span = meta.span();
             let cfg = AttributeParser::parse_single_args(
                 sess,
                 cfg_span,
                 cfg_span,
                 AttrStyle::Inner,
-                AttrPath { segments: vec![sym::cfg_select].into_boxed_slice(), span: cfg_span },
+                AttrPath {
+                    segments: vec![Ident::from_str("cfg_select")].into_boxed_slice(),
+                    span: cfg_span,
+                },
                 None,
                 ParsedDescription::Macro,
                 cfg_span,
                 lint_node_id,
-                // Doesn't matter what the target actually is here.
-                Target::Crate,
                 features,
-                ShouldEmit::ErrorsAndLints { recovery: Recovery::Allowed },
+                ShouldEmit::ErrorsAndLints,
                 &meta,
                 parse_cfg_entry,
                 &AttributeTemplate::default(),
@@ -128,102 +86,5 @@ pub fn parse_cfg_select(
         }
     }
 
-    if let Some(features) = features
-        && features.enabled(sym::cfg_select)
-    {
-        let it = branches
-            .reachable
-            .iter()
-            .map(|(entry, _, _)| CfgSelectPredicate::Cfg(entry.clone()))
-            .chain(branches.wildcard.as_ref().map(|(t, _, _)| CfgSelectPredicate::Wildcard(*t)))
-            .chain(
-                branches.unreachable.iter().map(|(entry, _, _)| CfgSelectPredicate::clone(entry)),
-            );
-
-        lint_unreachable(p, it, lint_node_id);
-    }
-
     Ok(branches)
 }
-
-fn lint_unreachable(
-    p: &mut Parser<'_>,
-    predicates: impl Iterator<Item = CfgSelectPredicate>,
-    lint_node_id: NodeId,
-) {
-    // Symbols that have a known value.
-    let mut known = FxHashMap::<Symbol, bool>::default();
-    let mut wildcard_span = None;
-    let mut it = predicates;
-
-    let branch_is_unreachable = |predicate: CfgSelectPredicate, wildcard_span| {
-        let span = predicate.span();
-        p.psess.buffer_lint(
-            UNREACHABLE_CFG_SELECT_PREDICATES,
-            span,
-            lint_node_id,
-            BuiltinLintDiag::UnreachableCfg { span, wildcard_span },
-        );
-    };
-
-    for predicate in &mut it {
-        let CfgSelectPredicate::Cfg(ref cfg_entry) = predicate else {
-            wildcard_span = Some(predicate.span());
-            break;
-        };
-
-        match cfg_entry {
-            CfgEntry::Bool(true, _) => {
-                wildcard_span = Some(predicate.span());
-                break;
-            }
-            CfgEntry::Bool(false, _) => continue,
-            CfgEntry::NameValue { name, value, .. } => match value {
-                None => {
-                    // `name` will be false in all subsequent branches.
-                    let current = known.insert(*name, false);
-
-                    match current {
-                        None => continue,
-                        Some(false) => {
-                            branch_is_unreachable(predicate, None);
-                            break;
-                        }
-                        Some(true) => {
-                            // this branch will be taken, so all subsequent branches are unreachable.
-                            break;
-                        }
-                    }
-                }
-                Some(_) => { /* for now we don't bother solving these */ }
-            },
-            CfgEntry::Not(inner, _) => match &**inner {
-                CfgEntry::NameValue { name, value: None, .. } => {
-                    // `name` will be true in all subsequent branches.
-                    let current = known.insert(*name, true);
-
-                    match current {
-                        None => continue,
-                        Some(true) => {
-                            branch_is_unreachable(predicate, None);
-                            break;
-                        }
-                        Some(false) => {
-                            // this branch will be taken, so all subsequent branches are unreachable.
-                            break;
-                        }
-                    }
-                }
-                _ => { /* for now we don't bother solving these */ }
-            },
-            CfgEntry::All(_, _) | CfgEntry::Any(_, _) => {
-                /* for now we don't bother solving these */
-            }
-            CfgEntry::Version(..) => { /* don't bother solving these */ }
-        }
-    }
-
-    for predicate in it {
-        branch_is_unreachable(predicate, wildcard_span)
-    }
-}

compiler/rustc_attr_parsing/src/attributes/cfi_encoding.rs

@@ -1,33 +0,0 @@
-use super::prelude::*;
-pub(crate) struct CfiEncodingParser;
-impl<S: Stage> SingleAttributeParser<S> for CfiEncodingParser {
-    const PATH: &[Symbol] = &[sym::cfi_encoding];
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowListWarnRest(&[
-        Allow(Target::Struct),
-        Allow(Target::ForeignTy),
-        Allow(Target::Enum),
-        Allow(Target::Union),
-    ]);
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "encoding");
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(name_value) = args.name_value() else {
-            cx.expected_name_value(cx.attr_span, Some(sym::cfi_encoding));
-            return None;
-        };
-
-        let Some(value_str) = name_value.value_as_str() else {
-            cx.expected_string_literal(name_value.value_span, None);
-            return None;
-        };
-
-        if value_str.as_str().trim().is_empty() {
-            cx.expected_non_empty_string_literal(name_value.value_span);
-            return None;
-        }
-
-        Some(AttributeKind::CfiEncoding { encoding: value_str })
-    }
-}

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -23,9 +23,9 @@ impl<S: Stage> SingleAttributeParser<S> for OptimizeParser {
     ]);
     const TEMPLATE: AttributeTemplate = template!(List: &["size", "speed", "none"]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
+            cx.expected_list(cx.attr_span);
             return None;
         };
 
@@ -57,6 +57,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for ColdParser {
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
+        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::ForeignFn),
         Allow(Target::Closure),
@@ -83,7 +84,7 @@ impl<S: Stage> SingleAttributeParser<S> for CoverageParser {
     ]);
     const TEMPLATE: AttributeTemplate = template!(OneOf: &[sym::off, sym::on]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(args) = args.list() else {
             cx.expected_specific_argument_and_list(cx.attr_span, &[sym::on, sym::off]);
             return None;
@@ -134,7 +135,7 @@ impl<S: Stage> SingleAttributeParser<S> for ExportNameParser {
     ]);
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -163,7 +164,7 @@ impl<S: Stage> SingleAttributeParser<S> for ObjcClassParser {
         AllowedTargets::AllowList(&[Allow(Target::ForeignStatic)]);
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "ClassName");
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -181,7 +182,7 @@ impl<S: Stage> SingleAttributeParser<S> for ObjcClassParser {
             cx.emit_err(NullOnObjcClass { span: nv.value_span });
             return None;
         }
-        Some(AttributeKind::RustcObjcClass { classname, span: cx.attr_span })
+        Some(AttributeKind::ObjcClass { classname, span: cx.attr_span })
     }
 }
 
@@ -195,7 +196,7 @@ impl<S: Stage> SingleAttributeParser<S> for ObjcSelectorParser {
         AllowedTargets::AllowList(&[Allow(Target::ForeignStatic)]);
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "methodName");
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -213,7 +214,7 @@ impl<S: Stage> SingleAttributeParser<S> for ObjcSelectorParser {
             cx.emit_err(NullOnObjcSelector { span: nv.value_span });
             return None;
         }
-        Some(AttributeKind::RustcObjcSelector { methname, span: cx.attr_span })
+        Some(AttributeKind::ObjcSelector { methname, span: cx.attr_span })
     }
 }
 
@@ -342,7 +343,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for TrackCallerParser {
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: false })), // `#[track_caller]` is inherited from trait methods
+        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::ForeignFn),
         Allow(Target::Closure),
         Warn(Target::MacroDef),
@@ -471,13 +472,13 @@ impl<S: Stage> AttributeParser<S> for UsedParser {
     }
 }
 
-fn parse_tf_attribute<S: Stage>(
+fn parse_tf_attribute<'c, S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
+    cx: &'c mut AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &'c ArgParser<'_>,
-) -> impl IntoIterator<Item = (Symbol, Span)> {
+) -> impl IntoIterator<Item = (Symbol, Span)> + 'c {
     let mut features = Vec::new();
     let ArgParser::List(list) = args else {
-        cx.expected_list(cx.attr_span, args);
+        cx.expected_list(cx.attr_span);
         return features;
     };
     if list.is_empty() {
@@ -528,10 +529,10 @@ impl<S: Stage> CombineAttributeParser<S> for TargetFeatureParser {
     };
     const TEMPLATE: AttributeTemplate = template!(List: &["enable = \"feat1, feat2\""]);
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item> {
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
         parse_tf_attribute(cx, args)
     }
 
@@ -566,10 +567,10 @@ impl<S: Stage> CombineAttributeParser<S> for ForceTargetFeatureParser {
         Allow(Target::Method(MethodKind::TraitImpl)),
     ]);
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item> {
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
         parse_tf_attribute(cx, args)
     }
 }
@@ -598,9 +599,9 @@ impl<S: Stage> SingleAttributeParser<S> for SanitizeParser {
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
+            cx.expected_list(cx.attr_span);
             return None;
         };
 
@@ -690,16 +691,6 @@ impl<S: Stage> SingleAttributeParser<S> for SanitizeParser {
     }
 }
 
-pub(crate) struct ThreadLocalParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for ThreadLocalParser {
-    const PATH: &[Symbol] = &[sym::thread_local];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const ALLOWED_TARGETS: AllowedTargets =
-        AllowedTargets::AllowList(&[Allow(Target::Static), Allow(Target::ForeignStatic)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::ThreadLocal;
-}
-
 pub(crate) struct RustcPassIndirectlyInNonRusticAbisParser;
 
 impl<S: Stage> NoArgsAttributeParser<S> for RustcPassIndirectlyInNonRusticAbisParser {
@@ -708,109 +699,3 @@ impl<S: Stage> NoArgsAttributeParser<S> for RustcPassIndirectlyInNonRusticAbisPa
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Struct)]);
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcPassIndirectlyInNonRusticAbis;
 }
-
-pub(crate) struct EiiForeignItemParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for EiiForeignItemParser {
-    const PATH: &[Symbol] = &[sym::rustc_eii_foreign_item];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::ForeignFn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::EiiForeignItem;
-}
-
-pub(crate) struct PatchableFunctionEntryParser;
-
-impl<S: Stage> SingleAttributeParser<S> for PatchableFunctionEntryParser {
-    const PATH: &[Symbol] = &[sym::patchable_function_entry];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
-    const TEMPLATE: AttributeTemplate = template!(List: &["prefix_nops = m, entry_nops = n"]);
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(meta_item_list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
-            return None;
-        };
-
-        let mut prefix = None;
-        let mut entry = None;
-
-        if meta_item_list.len() == 0 {
-            cx.expected_list(meta_item_list.span, args);
-            return None;
-        }
-
-        let mut errored = false;
-
-        for item in meta_item_list.mixed() {
-            let Some(meta_item) = item.meta_item() else {
-                errored = true;
-                cx.expected_name_value(item.span(), None);
-                continue;
-            };
-
-            let Some(name_value_lit) = meta_item.args().name_value() else {
-                errored = true;
-                cx.expected_name_value(item.span(), None);
-                continue;
-            };
-
-            let attrib_to_write = match meta_item.ident().map(|ident| ident.name) {
-                Some(sym::prefix_nops) => {
-                    // Duplicate prefixes are not allowed
-                    if prefix.is_some() {
-                        errored = true;
-                        cx.duplicate_key(meta_item.path().span(), sym::prefix_nops);
-                        continue;
-                    }
-                    &mut prefix
-                }
-                Some(sym::entry_nops) => {
-                    // Duplicate entries are not allowed
-                    if entry.is_some() {
-                        errored = true;
-                        cx.duplicate_key(meta_item.path().span(), sym::entry_nops);
-                        continue;
-                    }
-                    &mut entry
-                }
-                _ => {
-                    errored = true;
-                    cx.expected_specific_argument(
-                        meta_item.path().span(),
-                        &[sym::prefix_nops, sym::entry_nops],
-                    );
-                    continue;
-                }
-            };
-
-            let rustc_ast::LitKind::Int(val, _) = name_value_lit.value_as_lit().kind else {
-                errored = true;
-                cx.expected_integer_literal(name_value_lit.value_span);
-                continue;
-            };
-
-            let Ok(val) = val.get().try_into() else {
-                errored = true;
-                cx.expected_integer_literal_in_range(
-                    name_value_lit.value_span,
-                    u8::MIN as isize,
-                    u8::MAX as isize,
-                );
-                continue;
-            };
-
-            *attrib_to_write = Some(val);
-        }
-
-        if errored {
-            None
-        } else {
-            Some(AttributeKind::PatchableFunctionEntry {
-                prefix: prefix.unwrap_or(0),
-                entry: entry.unwrap_or(0),
-            })
-        }
-    }
-}

compiler/rustc_attr_parsing/src/attributes/confusables.rs

@@ -13,7 +13,7 @@ impl<S: Stage> AttributeParser<S> for ConfusablesParser {
         template!(List: &[r#""name1", "name2", ..."#]),
         |this, cx, args| {
             let Some(list) = args.list() else {
-                cx.expected_list(cx.attr_span, args);
+                cx.expected_list(cx.attr_span);
                 return;
             };
 
@@ -43,7 +43,7 @@ impl<S: Stage> AttributeParser<S> for ConfusablesParser {
             return None;
         }
 
-        Some(AttributeKind::RustcConfusables {
+        Some(AttributeKind::Confusables {
             symbols: self.confusables,
             first_span: self.first_span.unwrap(),
         })

compiler/rustc_attr_parsing/src/attributes/crate_level.rs

@@ -1,8 +1,4 @@
-use rustc_hir::attrs::{CrateType, WindowsSubsystemKind};
+use rustc_hir::attrs::WindowsSubsystemKind;
-use rustc_hir::lints::AttributeLintKind;
-use rustc_session::lint::builtin::UNKNOWN_CRATE_TYPES;
-use rustc_span::Symbol;
-use rustc_span::edit_distance::find_best_match_for_name;
 
 use super::prelude::*;
 
@@ -13,9 +9,9 @@ impl<S: Stage> SingleAttributeParser<S> for CrateNameParser {
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ArgParser::NameValue(n) = args else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -30,56 +26,6 @@ impl<S: Stage> SingleAttributeParser<S> for CrateNameParser {
     }
 }
 
-pub(crate) struct CrateTypeParser;
-
-impl<S: Stage> CombineAttributeParser<S> for CrateTypeParser {
-    const PATH: &[Symbol] = &[sym::crate_type];
-    type Item = CrateType;
-    const CONVERT: ConvertFn<Self::Item> = |items, _| AttributeKind::CrateType(items);
-
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-
-    const TEMPLATE: AttributeTemplate =
-        template!(NameValueStr: "crate type", "https://doc.rust-lang.org/reference/linkage.html");
-
-    fn extend(
-        cx: &mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
-    ) -> impl IntoIterator<Item = Self::Item> {
-        let ArgParser::NameValue(n) = args else {
-            cx.expected_name_value(cx.attr_span, None);
-            return None;
-        };
-
-        let Some(crate_type) = n.value_as_str() else {
-            cx.expected_string_literal(n.value_span, Some(n.value_as_lit()));
-            return None;
-        };
-
-        let Ok(crate_type) = crate_type.try_into() else {
-            // We don't error on invalid `#![crate_type]` when not applied to a crate
-            if cx.shared.target == Target::Crate {
-                let candidate = find_best_match_for_name(
-                    &CrateType::all_stable().iter().map(|(name, _)| *name).collect::<Vec<_>>(),
-                    crate_type,
-                    None,
-                );
-                cx.emit_lint(
-                    UNKNOWN_CRATE_TYPES,
-                    AttributeLintKind::CrateTypeUnknown {
-                        span: n.value_span,
-                        suggested: candidate,
-                    },
-                    n.value_span,
-                );
-            }
-            return None;
-        };
-
-        Some(crate_type)
-    }
-}
-
 pub(crate) struct RecursionLimitParser;
 
 impl<S: Stage> SingleAttributeParser<S> for RecursionLimitParser {
@@ -87,9 +33,9 @@ impl<S: Stage> SingleAttributeParser<S> for RecursionLimitParser {
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "N", "https://doc.rust-lang.org/reference/attributes/limits.html#the-recursion_limit-attribute");
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ArgParser::NameValue(nv) = args else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -110,9 +56,9 @@ impl<S: Stage> SingleAttributeParser<S> for MoveSizeLimitParser {
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "N");
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ArgParser::NameValue(nv) = args else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -133,9 +79,9 @@ impl<S: Stage> SingleAttributeParser<S> for TypeLengthLimitParser {
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "N");
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ArgParser::NameValue(nv) = args else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -156,9 +102,9 @@ impl<S: Stage> SingleAttributeParser<S> for PatternComplexityLimitParser {
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "N");
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ArgParser::NameValue(nv) = args else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -177,7 +123,7 @@ pub(crate) struct NoCoreParser;
 impl<S: Stage> NoArgsAttributeParser<S> for NoCoreParser {
     const PATH: &[Symbol] = &[sym::no_core];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::NoCore;
 }
 
@@ -186,25 +132,16 @@ pub(crate) struct NoStdParser;
 impl<S: Stage> NoArgsAttributeParser<S> for NoStdParser {
     const PATH: &[Symbol] = &[sym::no_std];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::NoStd;
 }
 
-pub(crate) struct NoMainParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for NoMainParser {
-    const PATH: &[Symbol] = &[sym::no_main];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::NoMain;
-}
-
 pub(crate) struct RustcCoherenceIsCoreParser;
 
 impl<S: Stage> NoArgsAttributeParser<S> for RustcCoherenceIsCoreParser {
     const PATH: &[Symbol] = &[sym::rustc_coherence_is_core];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcCoherenceIsCore;
 }
 
@@ -214,10 +151,10 @@ impl<S: Stage> SingleAttributeParser<S> for WindowsSubsystemParser {
     const PATH: &[Symbol] = &[sym::windows_subsystem];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::CrateLevel;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: ["windows", "console"], "https://doc.rust-lang.org/reference/runtime.html#the-windows_subsystem-attribute");
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(
                 args.span().unwrap_or(cx.inner_span),
@@ -238,66 +175,3 @@ impl<S: Stage> SingleAttributeParser<S> for WindowsSubsystemParser {
         Some(AttributeKind::WindowsSubsystem(kind, cx.attr_span))
     }
 }
-
-pub(crate) struct PanicRuntimeParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for PanicRuntimeParser {
-    const PATH: &[Symbol] = &[sym::panic_runtime];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::PanicRuntime;
-}
-
-pub(crate) struct NeedsPanicRuntimeParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for NeedsPanicRuntimeParser {
-    const PATH: &[Symbol] = &[sym::needs_panic_runtime];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::NeedsPanicRuntime;
-}
-
-pub(crate) struct ProfilerRuntimeParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for ProfilerRuntimeParser {
-    const PATH: &[Symbol] = &[sym::profiler_runtime];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::ProfilerRuntime;
-}
-
-pub(crate) struct NoBuiltinsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for NoBuiltinsParser {
-    const PATH: &[Symbol] = &[sym::no_builtins];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::NoBuiltins;
-}
-
-pub(crate) struct RustcPreserveUbChecksParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcPreserveUbChecksParser {
-    const PATH: &[Symbol] = &[sym::rustc_preserve_ub_checks];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcPreserveUbChecks;
-}
-
-pub(crate) struct RustcNoImplicitBoundsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcNoImplicitBoundsParser {
-    const PATH: &[Symbol] = &[sym::rustc_no_implicit_bounds];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcNoImplicitBounds;
-}
-
-pub(crate) struct DefaultLibAllocatorParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for DefaultLibAllocatorParser {
-    const PATH: &[Symbol] = &[sym::default_lib_allocator];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::DefaultLibAllocator;
-}

compiler/rustc_attr_parsing/src/attributes/debugger.rs

@@ -16,12 +16,12 @@ impl<S: Stage> CombineAttributeParser<S> for DebuggerViualizerParser {
     type Item = DebugVisualizer;
     const CONVERT: ConvertFn<Self::Item> = |v, _| AttributeKind::DebuggerVisualizer(v);
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item> {
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
         let Some(l) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
+            cx.expected_list(args.span().unwrap_or(cx.attr_span));
             return None;
         };
         let Some(single) = l.single() else {

compiler/rustc_attr_parsing/src/attributes/deprecation.rs

@@ -1,5 +1,4 @@
 use rustc_hir::attrs::{DeprecatedSince, Deprecation};
-use rustc_hir::{RustcVersion, VERSION_PLACEHOLDER};
 
 use super::prelude::*;
 use super::util::parse_version;
@@ -13,15 +12,15 @@ fn get<S: Stage>(
     cx: &AcceptContext<'_, '_, S>,
     name: Symbol,
     param_span: Span,
-    arg: &ArgParser,
+    arg: &ArgParser<'_>,
-    item: Option<Symbol>,
+    item: &Option<Symbol>,
-) -> Option<Ident> {
+) -> Option<Symbol> {
     if item.is_some() {
         cx.duplicate_key(param_span, name);
         return None;
     }
     if let Some(v) = arg.name_value() {
-        if let Some(value_str) = v.value_as_ident() {
+        if let Some(value_str) = v.value_as_str() {
             Some(value_str)
         } else {
             cx.expected_string_literal(v.value_span, Some(&v.value_as_lit()));
@@ -69,11 +68,11 @@ impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
         NameValueStr: "reason"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let features = cx.features();
 
         let mut since = None;
-        let mut note: Option<Ident> = None;
+        let mut note = None;
         let mut suggestion = None;
 
         let is_rustc = features.staged_api();
@@ -93,16 +92,10 @@ impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
 
                     match ident_name {
                         Some(name @ sym::since) => {
-                            since = Some(get(cx, name, param.span(), param.args(), since)?.name);
+                            since = Some(get(cx, name, param.span(), param.args(), &since)?);
                         }
                         Some(name @ sym::note) => {
-                            note = Some(get(
+                            note = Some(get(cx, name, param.span(), param.args(), &note)?);
-                                cx,
-                                name,
-                                param.span(),
-                                param.args(),
-                                note.map(|ident| ident.name),
-                            )?);
                         }
                         Some(name @ sym::suggestion) => {
                             if !features.deprecated_suggestion() {
@@ -114,15 +107,16 @@ impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
                             }
 
                             suggestion =
-                                Some(get(cx, name, param.span(), param.args(), suggestion)?.name);
+                                Some(get(cx, name, param.span(), param.args(), &suggestion)?);
                         }
                         _ => {
-                            cx.expected_specific_argument(
+                            cx.unknown_key(
                                 param.span(),
+                                param.path().to_string(),
                                 if features.deprecated_suggestion() {
-                                    &[sym::since, sym::note, sym::suggestion]
+                                    &["since", "note", "suggestion"]
                                 } else {
-                                    &[sym::since, sym::note]
+                                    &["since", "note"]
                                 },
                             );
                             return None;
@@ -131,7 +125,7 @@ impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
                 }
             }
             ArgParser::NameValue(v) => {
-                let Some(value) = v.value_as_ident() else {
+                let Some(value) = v.value_as_str() else {
                     cx.expected_string_literal(v.value_span, Some(v.value_as_lit()));
                     return None;
                 };
@@ -144,8 +138,6 @@ impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
                 DeprecatedSince::Future
             } else if !is_rustc {
                 DeprecatedSince::NonStandard(since)
-            } else if since.as_str() == VERSION_PLACEHOLDER {
-                DeprecatedSince::RustcVersion(RustcVersion::CURRENT)
             } else if let Some(version) = parse_version(since) {
                 DeprecatedSince::RustcVersion(version)
             } else {

compiler/rustc_attr_parsing/src/attributes/do_not_recommend.rs

@@ -1,31 +0,0 @@
-use rustc_feature::{AttributeTemplate, template};
-use rustc_hir::attrs::AttributeKind;
-use rustc_hir::lints::AttributeLintKind;
-use rustc_session::lint::builtin::MALFORMED_DIAGNOSTIC_ATTRIBUTES;
-use rustc_span::{Symbol, sym};
-
-use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
-use crate::context::{AcceptContext, Stage};
-use crate::parser::ArgParser;
-use crate::target_checking::{ALL_TARGETS, AllowedTargets};
-
-pub(crate) struct DoNotRecommendParser;
-impl<S: Stage> SingleAttributeParser<S> for DoNotRecommendParser {
-    const PATH: &[Symbol] = &[sym::diagnostic, sym::do_not_recommend];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS); // Checked in check_attr.
-    const TEMPLATE: AttributeTemplate = template!(Word /*doesn't matter */);
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let attr_span = cx.attr_span;
-        if !matches!(args, ArgParser::NoArgs) {
-            cx.emit_lint(
-                MALFORMED_DIAGNOSTIC_ATTRIBUTES,
-                AttributeLintKind::DoNotRecommendDoesNotExpectArgs,
-                attr_span,
-            );
-        }
-        Some(AttributeKind::DoNotRecommend { attr_span })
-    }
-}

compiler/rustc_attr_parsing/src/attributes/doc.rs

@@ -1,760 +0,0 @@
-use rustc_ast::ast::{AttrStyle, LitKind, MetaItemLit};
-use rustc_feature::template;
-use rustc_hir::Target;
-use rustc_hir::attrs::{
-    AttributeKind, CfgEntry, CfgHideShow, CfgInfo, DocAttribute, DocInline, HideOrShow,
-};
-use rustc_hir::lints::AttributeLintKind;
-use rustc_span::{Span, Symbol, edition, sym};
-use thin_vec::ThinVec;
-
-use super::prelude::{ALL_TARGETS, AllowedTargets};
-use super::{AcceptMapping, AttributeParser};
-use crate::context::{AcceptContext, FinalizeContext, Stage};
-use crate::parser::{ArgParser, MetaItemOrLitParser, MetaItemParser, OwnedPathParser};
-use crate::session_diagnostics::{
-    DocAliasBadChar, DocAliasEmpty, DocAliasMalformed, DocAliasStartEnd, DocAttrNotCrateLevel,
-    DocAttributeNotAttribute, DocKeywordNotKeyword,
-};
-
-fn check_keyword<S: Stage>(cx: &mut AcceptContext<'_, '_, S>, keyword: Symbol, span: Span) -> bool {
-    // FIXME: Once rustdoc can handle URL conflicts on case insensitive file systems, we
-    // can remove the `SelfTy` case here, remove `sym::SelfTy`, and update the
-    // `#[doc(keyword = "SelfTy")` attribute in `library/std/src/keyword_docs.rs`.
-    if keyword.is_reserved(|| edition::LATEST_STABLE_EDITION)
-        || keyword.is_weak()
-        || keyword == sym::SelfTy
-    {
-        return true;
-    }
-    cx.emit_err(DocKeywordNotKeyword { span, keyword });
-    false
-}
-
-fn check_attribute<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
-    attribute: Symbol,
-    span: Span,
-) -> bool {
-    // FIXME: This should support attributes with namespace like `diagnostic::do_not_recommend`.
-    if rustc_feature::BUILTIN_ATTRIBUTE_MAP.contains_key(&attribute) {
-        return true;
-    }
-    cx.emit_err(DocAttributeNotAttribute { span, attribute });
-    false
-}
-
-/// Checks that an attribute is *not* used at the crate level. Returns `true` if valid.
-fn check_attr_not_crate_level<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
-    span: Span,
-    attr_name: Symbol,
-) -> bool {
-    if cx.shared.target == Target::Crate {
-        cx.emit_err(DocAttrNotCrateLevel { span, attr_name });
-        return false;
-    }
-    true
-}
-
-/// Checks that an attribute is used at the crate level. Returns `true` if valid.
-fn check_attr_crate_level<S: Stage>(cx: &mut AcceptContext<'_, '_, S>, span: Span) -> bool {
-    if cx.shared.target != Target::Crate {
-        cx.emit_lint(
-            rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-            AttributeLintKind::AttrCrateLevelOnly,
-            span,
-        );
-        return false;
-    }
-    true
-}
-
-// FIXME: To be removed once merged and replace with `cx.expected_name_value(span, _name)`.
-fn expected_name_value<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
-    span: Span,
-    _name: Option<Symbol>,
-) {
-    cx.emit_lint(
-        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-        AttributeLintKind::ExpectedNameValue,
-        span,
-    );
-}
-
-// FIXME: remove this method once merged and use `cx.expected_no_args(span)` instead.
-fn expected_no_args<S: Stage>(cx: &mut AcceptContext<'_, '_, S>, span: Span) {
-    cx.emit_lint(
-        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-        AttributeLintKind::ExpectedNoArgs,
-        span,
-    );
-}
-
-// FIXME: remove this method once merged and use `cx.expected_no_args(span)` instead.
-// cx.expected_string_literal(span, _actual_literal);
-fn expected_string_literal<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
-    span: Span,
-    _actual_literal: Option<&MetaItemLit>,
-) {
-    cx.emit_lint(
-        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-        AttributeLintKind::MalformedDoc,
-        span,
-    );
-}
-
-fn parse_keyword_and_attribute<S: Stage>(
-    cx: &mut AcceptContext<'_, '_, S>,
-    path: &OwnedPathParser,
-    args: &ArgParser,
-    attr_value: &mut Option<(Symbol, Span)>,
-    attr_name: Symbol,
-) {
-    let Some(nv) = args.name_value() else {
-        expected_name_value(cx, args.span().unwrap_or(path.span()), path.word_sym());
-        return;
-    };
-
-    let Some(value) = nv.value_as_str() else {
-        expected_string_literal(cx, nv.value_span, Some(nv.value_as_lit()));
-        return;
-    };
-
-    let ret = if attr_name == sym::keyword {
-        check_keyword(cx, value, nv.value_span)
-    } else {
-        check_attribute(cx, value, nv.value_span)
-    };
-    if !ret {
-        return;
-    }
-
-    let span = path.span();
-    if attr_value.is_some() {
-        cx.duplicate_key(span, path.word_sym().unwrap());
-        return;
-    }
-
-    if !check_attr_not_crate_level(cx, span, attr_name) {
-        return;
-    }
-
-    *attr_value = Some((value, span));
-}
-
-#[derive(Default, Debug)]
-pub(crate) struct DocParser {
-    attribute: DocAttribute,
-    nb_doc_attrs: usize,
-}
-
-impl DocParser {
-    fn parse_single_test_doc_attr_item<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        mip: &MetaItemParser,
-    ) {
-        let path = mip.path();
-        let args = mip.args();
-
-        match path.word_sym() {
-            Some(sym::no_crate_inject) => {
-                if let Err(span) = args.no_args() {
-                    expected_no_args(cx, span);
-                    return;
-                }
-
-                if let Some(used_span) = self.attribute.no_crate_inject {
-                    let unused_span = path.span();
-                    cx.emit_lint(
-                        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                        AttributeLintKind::UnusedDuplicate {
-                            this: unused_span,
-                            other: used_span,
-                            warning: true,
-                        },
-                        unused_span,
-                    );
-                    return;
-                }
-
-                if !check_attr_crate_level(cx, path.span()) {
-                    return;
-                }
-
-                self.attribute.no_crate_inject = Some(path.span())
-            }
-            Some(sym::attr) => {
-                let Some(list) = args.list() else {
-                    // FIXME: remove this method once merged and uncomment the line below instead.
-                    // cx.expected_list(cx.attr_span, args);
-                    let span = cx.attr_span;
-                    cx.emit_lint(
-                        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                        AttributeLintKind::MalformedDoc,
-                        span,
-                    );
-                    return;
-                };
-
-                // FIXME: convert list into a Vec of `AttributeKind` because current code is awful.
-                for attr in list.mixed() {
-                    self.attribute.test_attrs.push(attr.span());
-                }
-            }
-            Some(name) => {
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocTestUnknown { name },
-                    path.span(),
-                );
-            }
-            None => {
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocTestLiteral,
-                    path.span(),
-                );
-            }
-        }
-    }
-
-    fn add_alias<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        alias: Symbol,
-        span: Span,
-    ) {
-        let attr_str = "`#[doc(alias = \"...\")]`";
-        if alias == sym::empty {
-            cx.emit_err(DocAliasEmpty { span, attr_str });
-            return;
-        }
-
-        let alias_str = alias.as_str();
-        if let Some(c) =
-            alias_str.chars().find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
-        {
-            cx.emit_err(DocAliasBadChar { span, attr_str, char_: c });
-            return;
-        }
-        if alias_str.starts_with(' ') || alias_str.ends_with(' ') {
-            cx.emit_err(DocAliasStartEnd { span, attr_str });
-            return;
-        }
-        if !check_attr_not_crate_level(cx, span, sym::alias) {
-            return;
-        }
-
-        if let Some(first_definition) = self.attribute.aliases.get(&alias).copied() {
-            cx.emit_lint(
-                rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
-                AttributeLintKind::DuplicateDocAlias { first_definition },
-                span,
-            );
-        }
-
-        self.attribute.aliases.insert(alias, span);
-    }
-
-    fn parse_alias<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        path: &OwnedPathParser,
-        args: &ArgParser,
-    ) {
-        match args {
-            ArgParser::NoArgs => {
-                cx.emit_err(DocAliasMalformed { span: args.span().unwrap_or(path.span()) });
-            }
-            ArgParser::List(list) => {
-                for i in list.mixed() {
-                    let Some(alias) = i.lit().and_then(|i| i.value_str()) else {
-                        cx.expected_string_literal(i.span(), i.lit());
-                        continue;
-                    };
-
-                    self.add_alias(cx, alias, i.span());
-                }
-            }
-            ArgParser::NameValue(nv) => {
-                let Some(alias) = nv.value_as_str() else {
-                    cx.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
-                    return;
-                };
-                self.add_alias(cx, alias, nv.value_span);
-            }
-        }
-    }
-
-    fn parse_inline<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        path: &OwnedPathParser,
-        args: &ArgParser,
-        inline: DocInline,
-    ) {
-        if let Err(span) = args.no_args() {
-            expected_no_args(cx, span);
-            return;
-        }
-
-        self.attribute.inline.push((inline, path.span()));
-    }
-
-    fn parse_cfg<S: Stage>(&mut self, cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) {
-        // This function replaces cases like `cfg(all())` with `true`.
-        fn simplify_cfg(cfg_entry: &mut CfgEntry) {
-            match cfg_entry {
-                CfgEntry::All(cfgs, span) if cfgs.is_empty() => {
-                    *cfg_entry = CfgEntry::Bool(true, *span)
-                }
-                CfgEntry::Any(cfgs, span) if cfgs.is_empty() => {
-                    *cfg_entry = CfgEntry::Bool(false, *span)
-                }
-                CfgEntry::Not(cfg, _) => simplify_cfg(cfg),
-                _ => {}
-            }
-        }
-        if let Some(mut cfg_entry) = super::cfg::parse_cfg(cx, args) {
-            simplify_cfg(&mut cfg_entry);
-            self.attribute.cfg.push(cfg_entry);
-        }
-    }
-
-    fn parse_auto_cfg<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        path: &OwnedPathParser,
-        args: &ArgParser,
-    ) {
-        match args {
-            ArgParser::NoArgs => {
-                self.attribute.auto_cfg_change.push((true, path.span()));
-            }
-            ArgParser::List(list) => {
-                for meta in list.mixed() {
-                    let MetaItemOrLitParser::MetaItemParser(item) = meta else {
-                        cx.emit_lint(
-                            rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                            AttributeLintKind::DocAutoCfgExpectsHideOrShow,
-                            meta.span(),
-                        );
-                        continue;
-                    };
-                    let (kind, attr_name) = match item.path().word_sym() {
-                        Some(sym::hide) => (HideOrShow::Hide, sym::hide),
-                        Some(sym::show) => (HideOrShow::Show, sym::show),
-                        _ => {
-                            cx.emit_lint(
-                                rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                                AttributeLintKind::DocAutoCfgExpectsHideOrShow,
-                                item.span(),
-                            );
-                            continue;
-                        }
-                    };
-                    let ArgParser::List(list) = item.args() else {
-                        cx.emit_lint(
-                            rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                            AttributeLintKind::DocAutoCfgHideShowExpectsList { attr_name },
-                            item.span(),
-                        );
-                        continue;
-                    };
-
-                    let mut cfg_hide_show = CfgHideShow { kind, values: ThinVec::new() };
-
-                    for item in list.mixed() {
-                        let MetaItemOrLitParser::MetaItemParser(sub_item) = item else {
-                            cx.emit_lint(
-                                rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                                AttributeLintKind::DocAutoCfgHideShowUnexpectedItem { attr_name },
-                                item.span(),
-                            );
-                            continue;
-                        };
-                        match sub_item.args() {
-                            a @ (ArgParser::NoArgs | ArgParser::NameValue(_)) => {
-                                let Some(name) = sub_item.path().word_sym() else {
-                                    // FIXME: remove this method once merged and uncomment the line
-                                    // below instead.
-                                    // cx.expected_identifier(sub_item.path().span());
-                                    cx.emit_lint(
-                                        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                                        AttributeLintKind::MalformedDoc,
-                                        sub_item.path().span(),
-                                    );
-                                    continue;
-                                };
-                                if let Ok(CfgEntry::NameValue { name, value, .. }) =
-                                    super::cfg::parse_name_value(
-                                        name,
-                                        sub_item.path().span(),
-                                        a.name_value(),
-                                        sub_item.span(),
-                                        cx,
-                                    )
-                                {
-                                    cfg_hide_show.values.push(CfgInfo {
-                                        name,
-                                        name_span: sub_item.path().span(),
-                                        // If `value` is `Some`, `a.name_value()` will always return
-                                        // `Some` as well.
-                                        value: value
-                                            .map(|v| (v, a.name_value().unwrap().value_span)),
-                                    })
-                                }
-                            }
-                            _ => {
-                                cx.emit_lint(
-                                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                                    AttributeLintKind::DocAutoCfgHideShowUnexpectedItem {
-                                        attr_name,
-                                    },
-                                    sub_item.span(),
-                                );
-                                continue;
-                            }
-                        }
-                    }
-                    self.attribute.auto_cfg.push((cfg_hide_show, path.span()));
-                }
-            }
-            ArgParser::NameValue(nv) => {
-                let MetaItemLit { kind: LitKind::Bool(bool_value), span, .. } = nv.value_as_lit()
-                else {
-                    cx.emit_lint(
-                        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                        AttributeLintKind::DocAutoCfgWrongLiteral,
-                        nv.value_span,
-                    );
-                    return;
-                };
-                self.attribute.auto_cfg_change.push((*bool_value, *span));
-            }
-        }
-    }
-
-    fn parse_single_doc_attr_item<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        mip: &MetaItemParser,
-    ) {
-        let path = mip.path();
-        let args = mip.args();
-
-        macro_rules! no_args {
-            ($ident: ident) => {{
-                if let Err(span) = args.no_args() {
-                    expected_no_args(cx, span);
-                    return;
-                }
-
-                // FIXME: It's errorring when the attribute is passed multiple times on the command
-                // line.
-                // The right fix for this would be to only check this rule if the attribute is
-                // not set on the command line but directly in the code.
-                // if self.attribute.$ident.is_some() {
-                //     cx.duplicate_key(path.span(), path.word_sym().unwrap());
-                //     return;
-                // }
-
-                self.attribute.$ident = Some(path.span());
-            }};
-        }
-        macro_rules! no_args_and_not_crate_level {
-            ($ident: ident) => {{
-                if let Err(span) = args.no_args() {
-                    expected_no_args(cx, span);
-                    return;
-                }
-                let span = path.span();
-                if !check_attr_not_crate_level(cx, span, sym::$ident) {
-                    return;
-                }
-                self.attribute.$ident = Some(span);
-            }};
-        }
-        macro_rules! no_args_and_crate_level {
-            ($ident: ident) => {{
-                if let Err(span) = args.no_args() {
-                    expected_no_args(cx, span);
-                    return;
-                }
-                let span = path.span();
-                if !check_attr_crate_level(cx, span) {
-                    return;
-                }
-                self.attribute.$ident = Some(span);
-            }};
-        }
-        macro_rules! string_arg_and_crate_level {
-            ($ident: ident) => {{
-                let Some(nv) = args.name_value() else {
-                    expected_name_value(cx, args.span().unwrap_or(path.span()), path.word_sym());
-                    return;
-                };
-
-                let Some(s) = nv.value_as_str() else {
-                    expected_string_literal(cx, nv.value_span, Some(nv.value_as_lit()));
-                    return;
-                };
-
-                if !check_attr_crate_level(cx, path.span()) {
-                    return;
-                }
-
-                // FIXME: It's errorring when the attribute is passed multiple times on the command
-                // line.
-                // The right fix for this would be to only check this rule if the attribute is
-                // not set on the command line but directly in the code.
-                // if self.attribute.$ident.is_some() {
-                //     cx.duplicate_key(path.span(), path.word_sym().unwrap());
-                //     return;
-                // }
-
-                self.attribute.$ident = Some((s, path.span()));
-            }};
-        }
-
-        match path.word_sym() {
-            Some(sym::alias) => self.parse_alias(cx, path, args),
-            Some(sym::hidden) => no_args!(hidden),
-            Some(sym::html_favicon_url) => string_arg_and_crate_level!(html_favicon_url),
-            Some(sym::html_logo_url) => string_arg_and_crate_level!(html_logo_url),
-            Some(sym::html_no_source) => no_args_and_crate_level!(html_no_source),
-            Some(sym::html_playground_url) => string_arg_and_crate_level!(html_playground_url),
-            Some(sym::html_root_url) => string_arg_and_crate_level!(html_root_url),
-            Some(sym::issue_tracker_base_url) => {
-                string_arg_and_crate_level!(issue_tracker_base_url)
-            }
-            Some(sym::inline) => self.parse_inline(cx, path, args, DocInline::Inline),
-            Some(sym::no_inline) => self.parse_inline(cx, path, args, DocInline::NoInline),
-            Some(sym::masked) => no_args!(masked),
-            Some(sym::cfg) => self.parse_cfg(cx, args),
-            Some(sym::notable_trait) => no_args!(notable_trait),
-            Some(sym::keyword) => parse_keyword_and_attribute(
-                cx,
-                path,
-                args,
-                &mut self.attribute.keyword,
-                sym::keyword,
-            ),
-            Some(sym::attribute) => parse_keyword_and_attribute(
-                cx,
-                path,
-                args,
-                &mut self.attribute.attribute,
-                sym::attribute,
-            ),
-            Some(sym::fake_variadic) => no_args_and_not_crate_level!(fake_variadic),
-            Some(sym::search_unbox) => no_args_and_not_crate_level!(search_unbox),
-            Some(sym::rust_logo) => no_args_and_crate_level!(rust_logo),
-            Some(sym::auto_cfg) => self.parse_auto_cfg(cx, path, args),
-            Some(sym::test) => {
-                let Some(list) = args.list() else {
-                    cx.emit_lint(
-                        rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                        AttributeLintKind::DocTestTakesList,
-                        args.span().unwrap_or(path.span()),
-                    );
-                    return;
-                };
-
-                for i in list.mixed() {
-                    match i {
-                        MetaItemOrLitParser::MetaItemParser(mip) => {
-                            self.parse_single_test_doc_attr_item(cx, mip);
-                        }
-                        MetaItemOrLitParser::Lit(lit) => {
-                            // FIXME: remove this method once merged and uncomment the line
-                            // below instead.
-                            // cx.unexpected_literal(lit.span);
-                            cx.emit_lint(
-                                rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                                AttributeLintKind::MalformedDoc,
-                                lit.span,
-                            );
-                        }
-                    }
-                }
-            }
-            Some(sym::spotlight) => {
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocUnknownSpotlight { span: path.span() },
-                    path.span(),
-                );
-            }
-            Some(sym::include) if let Some(nv) = args.name_value() => {
-                let inner = match cx.attr_style {
-                    AttrStyle::Outer => "",
-                    AttrStyle::Inner => "!",
-                };
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocUnknownInclude {
-                        inner,
-                        value: nv.value_as_lit().symbol,
-                        span: path.span(),
-                    },
-                    path.span(),
-                );
-            }
-            Some(name @ (sym::passes | sym::no_default_passes)) => {
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocUnknownPasses { name, span: path.span() },
-                    path.span(),
-                );
-            }
-            Some(sym::plugins) => {
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocUnknownPlugins { span: path.span() },
-                    path.span(),
-                );
-            }
-            Some(name) => {
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocUnknownAny { name },
-                    path.span(),
-                );
-            }
-            None => {
-                let full_name =
-                    path.segments().map(|s| s.as_str()).intersperse("::").collect::<String>();
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::DocUnknownAny { name: Symbol::intern(&full_name) },
-                    path.span(),
-                );
-            }
-        }
-    }
-
-    fn accept_single_doc_attr<S: Stage>(
-        &mut self,
-        cx: &mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
-    ) {
-        match args {
-            ArgParser::NoArgs => {
-                let suggestions = cx.suggestions();
-                let span = cx.attr_span;
-                cx.emit_lint(
-                    rustc_session::lint::builtin::INVALID_DOC_ATTRIBUTES,
-                    AttributeLintKind::IllFormedAttributeInput { suggestions, docs: None },
-                    span,
-                );
-            }
-            ArgParser::List(items) => {
-                for i in items.mixed() {
-                    match i {
-                        MetaItemOrLitParser::MetaItemParser(mip) => {
-                            self.nb_doc_attrs += 1;
-                            self.parse_single_doc_attr_item(cx, mip);
-                        }
-                        MetaItemOrLitParser::Lit(lit) => {
-                            expected_name_value(cx, lit.span, None);
-                        }
-                    }
-                }
-            }
-            ArgParser::NameValue(nv) => {
-                if nv.value_as_str().is_none() {
-                    expected_string_literal(cx, nv.value_span, Some(nv.value_as_lit()));
-                } else {
-                    unreachable!(
-                        "Should have been handled at the same time as sugar-syntaxed doc comments"
-                    );
-                }
-            }
-        }
-    }
-}
-
-impl<S: Stage> AttributeParser<S> for DocParser {
-    const ATTRIBUTES: AcceptMapping<Self, S> = &[(
-        &[sym::doc],
-        template!(
-            List: &[
-                "alias",
-                "attribute",
-                "hidden",
-                "html_favicon_url",
-                "html_logo_url",
-                "html_no_source",
-                "html_playground_url",
-                "html_root_url",
-                "issue_tracker_base_url",
-                "inline",
-                "no_inline",
-                "masked",
-                "cfg",
-                "notable_trait",
-                "keyword",
-                "fake_variadic",
-                "search_unbox",
-                "rust_logo",
-                "auto_cfg",
-                "test",
-                "spotlight",
-                "include",
-                "no_default_passes",
-                "passes",
-                "plugins",
-            ],
-            NameValueStr: "string"
-        ),
-        |this, cx, args| {
-            this.accept_single_doc_attr(cx, args);
-        },
-    )];
-    // FIXME: Currently emitted from 2 different places, generating duplicated warnings.
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS);
-    // const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowListWarnRest(&[
-    //     Allow(Target::ExternCrate),
-    //     Allow(Target::Use),
-    //     Allow(Target::Static),
-    //     Allow(Target::Const),
-    //     Allow(Target::Fn),
-    //     Allow(Target::Mod),
-    //     Allow(Target::ForeignMod),
-    //     Allow(Target::TyAlias),
-    //     Allow(Target::Enum),
-    //     Allow(Target::Variant),
-    //     Allow(Target::Struct),
-    //     Allow(Target::Field),
-    //     Allow(Target::Union),
-    //     Allow(Target::Trait),
-    //     Allow(Target::TraitAlias),
-    //     Allow(Target::Impl { of_trait: true }),
-    //     Allow(Target::Impl { of_trait: false }),
-    //     Allow(Target::AssocConst),
-    //     Allow(Target::Method(MethodKind::Inherent)),
-    //     Allow(Target::Method(MethodKind::Trait { body: true })),
-    //     Allow(Target::Method(MethodKind::Trait { body: false })),
-    //     Allow(Target::Method(MethodKind::TraitImpl)),
-    //     Allow(Target::AssocTy),
-    //     Allow(Target::ForeignFn),
-    //     Allow(Target::ForeignStatic),
-    //     Allow(Target::ForeignTy),
-    //     Allow(Target::MacroDef),
-    //     Allow(Target::Crate),
-    //     Error(Target::WherePredicate),
-    // ]);
-
-    fn finalize(self, _cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
-        if self.nb_doc_attrs != 0 {
-            Some(AttributeKind::Doc(Box::new(self.attribute)))
-        } else {
-            None
-        }
-    }
-}

compiler/rustc_attr_parsing/src/attributes/dummy.rs

@@ -15,7 +15,7 @@ impl<S: Stage> SingleAttributeParser<S> for DummyParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS);
     const TEMPLATE: AttributeTemplate = template!(Word); // Anything, really
 
-    fn convert(_: &mut AcceptContext<'_, '_, S>, _: &ArgParser) -> Option<AttributeKind> {
+    fn convert(_: &mut AcceptContext<'_, '_, S>, _: &ArgParser<'_>) -> Option<AttributeKind> {
-        Some(AttributeKind::RustcDummy)
+        Some(AttributeKind::Dummy)
     }
 }

compiler/rustc_attr_parsing/src/attributes/inline.rs

@@ -3,14 +3,13 @@
 //                      SingleAttributeParser which is what we have two of here.
 
 use rustc_hir::attrs::{AttributeKind, InlineAttr};
-use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
 
 use super::prelude::*;
 
 pub(crate) struct InlineParser;
 
 impl<S: Stage> SingleAttributeParser<S> for InlineParser {
-    const PATH: &[Symbol] = &[sym::inline];
+    const PATH: &'static [Symbol] = &[sym::inline];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
@@ -34,7 +33,7 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
         "https://doc.rust-lang.org/reference/attributes/codegen.html#the-inline-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         match args {
             ArgParser::NoArgs => Some(AttributeKind::Inline(InlineAttr::Hint, cx.attr_span)),
             ArgParser::List(list) => {
@@ -57,7 +56,9 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
                 }
             }
             ArgParser::NameValue(_) => {
-                cx.warn_ill_formed_attribute_input(ILL_FORMED_ATTRIBUTE_INPUT);
+                let suggestions = cx.suggestions();
+                let span = cx.attr_span;
+                cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                 return None;
             }
         }
@@ -67,7 +68,7 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
 pub(crate) struct RustcForceInlineParser;
 
 impl<S: Stage> SingleAttributeParser<S> for RustcForceInlineParser {
-    const PATH: &[Symbol] = &[sym::rustc_force_inline];
+    const PATH: &'static [Symbol] = &[sym::rustc_force_inline];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
@@ -77,7 +78,7 @@ impl<S: Stage> SingleAttributeParser<S> for RustcForceInlineParser {
 
     const TEMPLATE: AttributeTemplate = template!(Word, List: &["reason"], NameValueStr: "reason");
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let reason = match args {
             ArgParser::NoArgs => None,
             ArgParser::List(list) => {

compiler/rustc_attr_parsing/src/attributes/instruction_set.rs

@@ -1,73 +0,0 @@
-use rustc_hir::attrs::InstructionSetAttr;
-
-use super::prelude::*;
-use crate::session_diagnostics;
-
-pub(crate) struct InstructionSetParser;
-
-impl<S: Stage> SingleAttributeParser<S> for InstructionSetParser {
-    const PATH: &[Symbol] = &[sym::instruction_set];
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowListWarnRest(&[
-        Allow(Target::Fn),
-        Allow(Target::Closure),
-        Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: true })),
-    ]);
-    const TEMPLATE: AttributeTemplate = template!(List: &["set"], "https://doc.rust-lang.org/reference/attributes/codegen.html#the-instruction_set-attribute");
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        const POSSIBLE_SYMBOLS: &[Symbol] = &[sym::arm_a32, sym::arm_t32];
-        const POSSIBLE_ARM_SYMBOLS: &[Symbol] = &[sym::a32, sym::t32];
-        let Some(maybe_meta_item) = args.list().and_then(MetaItemListParser::single) else {
-            cx.expected_specific_argument(cx.attr_span, POSSIBLE_SYMBOLS);
-            return None;
-        };
-
-        let Some(meta_item) = maybe_meta_item.meta_item() else {
-            cx.expected_specific_argument(maybe_meta_item.span(), POSSIBLE_SYMBOLS);
-            return None;
-        };
-
-        let mut segments = meta_item.path().segments();
-
-        let Some(architecture) = segments.next() else {
-            cx.expected_specific_argument(meta_item.span(), POSSIBLE_SYMBOLS);
-            return None;
-        };
-
-        let Some(instruction_set) = segments.next() else {
-            cx.expected_specific_argument(architecture.span, POSSIBLE_SYMBOLS);
-            return None;
-        };
-
-        let instruction_set = match architecture.name {
-            sym::arm => {
-                if !cx.sess.target.has_thumb_interworking {
-                    cx.dcx().emit_err(session_diagnostics::UnsupportedInstructionSet {
-                        span: cx.attr_span,
-                        instruction_set: sym::arm,
-                        current_target: &cx.sess.opts.target_triple,
-                    });
-                    return None;
-                }
-                match instruction_set.name {
-                    sym::a32 => InstructionSetAttr::ArmA32,
-                    sym::t32 => InstructionSetAttr::ArmT32,
-                    _ => {
-                        cx.expected_specific_argument(instruction_set.span, POSSIBLE_ARM_SYMBOLS);
-                        return None;
-                    }
-                }
-            }
-            _ => {
-                cx.expected_specific_argument(architecture.span, POSSIBLE_SYMBOLS);
-                return None;
-            }
-        };
-
-        Some(AttributeKind::InstructionSet(instruction_set))
-    }
-}

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -1,9 +1,7 @@
-use rustc_errors::msg;
 use rustc_feature::Features;
 use rustc_hir::attrs::AttributeKind::{LinkName, LinkOrdinal, LinkSection};
 use rustc_hir::attrs::*;
 use rustc_session::Session;
-use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
 use rustc_session::parse::feature_err;
 use rustc_span::kw;
 use rustc_target::spec::{Arch, BinaryFormat};
@@ -11,11 +9,12 @@ use rustc_target::spec::{Arch, BinaryFormat};
 use super::prelude::*;
 use super::util::parse_single_integer;
 use crate::attributes::cfg::parse_cfg_entry;
+use crate::fluent_generated;
 use crate::session_diagnostics::{
-    AsNeededCompatibility, BundleNeedsStatic, EmptyLinkName, ExportSymbolsNeedsStatic,
+    AsNeededCompatibility, BundleNeedsStatic, EmptyLinkName, ImportNameTypeRaw, ImportNameTypeX86,
-    ImportNameTypeRaw, ImportNameTypeX86, IncompatibleWasmLink, InvalidLinkModifier,
+    IncompatibleWasmLink, InvalidLinkModifier, LinkFrameworkApple, LinkOrdinalOutOfRange,
-    LinkFrameworkApple, LinkOrdinalOutOfRange, LinkRequiresName, MultipleModifiers,
+    LinkRequiresName, MultipleModifiers, NullOnLinkSection, RawDylibNoNul, RawDylibOnlyWindows,
-    NullOnLinkSection, RawDylibNoNul, RawDylibOnlyWindows, WholeArchiveNeedsStatic,
+    WholeArchiveNeedsStatic,
 };
 
 pub(crate) struct LinkNameParser;
@@ -33,7 +32,7 @@ impl<S: Stage> SingleAttributeParser<S> for LinkNameParser {
         "https://doc.rust-lang.org/reference/items/external-blocks.html#the-link_name-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -62,21 +61,23 @@ impl<S: Stage> CombineAttributeParser<S> for LinkParser {
         ], "https://doc.rust-lang.org/reference/items/external-blocks.html#the-link-attribute");
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS); //FIXME Still checked fully in `check_attr.rs`
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item> {
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
         let items = match args {
             ArgParser::List(list) => list,
             // This is an edgecase added because making this a hard error would break too many crates
             // Specifically `#[link = "dl"]` is accepted with a FCW
             // For more information, see https://github.com/rust-lang/rust/pull/143193
             ArgParser::NameValue(nv) if nv.value_as_str().is_some_and(|v| v == sym::dl) => {
-                cx.warn_ill_formed_attribute_input(ILL_FORMED_ATTRIBUTE_INPUT);
+                let suggestions = cx.suggestions();
+                let span = cx.attr_span;
+                cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                 return None;
             }
             _ => {
-                cx.expected_list(cx.attr_span, args);
+                cx.expected_list(cx.attr_span);
                 return None;
             }
         };
@@ -141,6 +142,8 @@ impl<S: Stage> CombineAttributeParser<S> for LinkParser {
 
                 macro report_unstable_modifier($feature: ident) {
                     if !features.$feature() {
+                        // FIXME: make this translatable
+                        #[expect(rustc::untranslatable_diagnostic)]
                         feature_err(
                             sess,
                             sym::$feature,
@@ -165,14 +168,6 @@ impl<S: Stage> CombineAttributeParser<S> for LinkParser {
                         cx.emit_err(BundleNeedsStatic { span });
                     }
 
-                    (sym::export_symbols, Some(NativeLibKind::Static { export_symbols, .. })) => {
-                        assign_modifier(export_symbols)
-                    }
-
-                    (sym::export_symbols, _) => {
-                        cx.emit_err(ExportSymbolsNeedsStatic { span });
-                    }
-
                     (sym::verbatim, _) => assign_modifier(&mut verbatim),
 
                     (
@@ -198,7 +193,6 @@ impl<S: Stage> CombineAttributeParser<S> for LinkParser {
                             span,
                             &[
                                 sym::bundle,
-                                sym::export_symbols,
                                 sym::verbatim,
                                 sym::whole_dash_archive,
                                 sym::as_dash_needed,
@@ -249,7 +243,7 @@ impl<S: Stage> CombineAttributeParser<S> for LinkParser {
 
 impl LinkParser {
     fn parse_link_name<S: Stage>(
-        item: &MetaItemParser,
+        item: &MetaItemParser<'_>,
         name: &mut Option<(Symbol, Span)>,
         cx: &mut AcceptContext<'_, '_, S>,
     ) -> bool {
@@ -274,7 +268,7 @@ impl LinkParser {
     }
 
     fn parse_link_kind<S: Stage>(
-        item: &MetaItemParser,
+        item: &MetaItemParser<'_>,
         kind: &mut Option<NativeLibKind>,
         cx: &mut AcceptContext<'_, '_, S>,
         sess: &Session,
@@ -294,9 +288,7 @@ impl LinkParser {
         };
 
         let link_kind = match link_kind {
-            kw::Static => {
+            kw::Static => NativeLibKind::Static { bundle: None, whole_archive: None },
-                NativeLibKind::Static { bundle: None, whole_archive: None, export_symbols: None }
-            }
             sym::dylib => NativeLibKind::Dylib { as_needed: None },
             sym::framework => {
                 if !sess.target.is_like_darwin {
@@ -316,7 +308,7 @@ impl LinkParser {
                         sess,
                         sym::raw_dylib_elf,
                         nv.value_span,
-                        msg!("link kind `raw-dylib` is unstable on ELF platforms"),
+                        fluent_generated::attr_parsing_raw_dylib_elf_unstable,
                     )
                     .emit();
                 } else {
@@ -331,7 +323,7 @@ impl LinkParser {
                         sess,
                         sym::link_arg_attribute,
                         nv.value_span,
-                        msg!("link kind `link-arg` is unstable"),
+                        fluent_generated::attr_parsing_link_arg_unstable,
                     )
                     .emit();
                 }
@@ -356,7 +348,7 @@ impl LinkParser {
     }
 
     fn parse_link_modifiers<S: Stage>(
-        item: &MetaItemParser,
+        item: &MetaItemParser<'_>,
         modifiers: &mut Option<(Symbol, Span)>,
         cx: &mut AcceptContext<'_, '_, S>,
     ) -> bool {
@@ -377,7 +369,7 @@ impl LinkParser {
     }
 
     fn parse_link_cfg<S: Stage>(
-        item: &MetaItemParser,
+        item: &MetaItemParser<'_>,
         cfg: &mut Option<CfgEntry>,
         cx: &mut AcceptContext<'_, '_, S>,
         sess: &Session,
@@ -388,7 +380,7 @@ impl LinkParser {
             return true;
         }
         let Some(link_cfg) = item.args().list() else {
-            cx.expected_list(item.span(), item.args());
+            cx.expected_list(item.span());
             return true;
         };
         let Some(link_cfg) = link_cfg.single() else {
@@ -396,14 +388,20 @@ impl LinkParser {
             return true;
         };
         if !features.link_cfg() {
-            feature_err(sess, sym::link_cfg, item.span(), msg!("link cfg is unstable")).emit();
+            feature_err(
+                sess,
+                sym::link_cfg,
+                item.span(),
+                fluent_generated::attr_parsing_link_cfg_unstable,
+            )
+            .emit();
         }
         *cfg = parse_cfg_entry(cx, link_cfg).ok();
         true
     }
 
     fn parse_link_wasm_import_module<S: Stage>(
-        item: &MetaItemParser,
+        item: &MetaItemParser<'_>,
         wasm_import_module: &mut Option<(Symbol, Span)>,
         cx: &mut AcceptContext<'_, '_, S>,
     ) -> bool {
@@ -424,7 +422,7 @@ impl LinkParser {
     }
 
     fn parse_link_import_name_type<S: Stage>(
-        item: &MetaItemParser,
+        item: &MetaItemParser<'_>,
         import_name_type: &mut Option<(PeImportNameType, Span)>,
         cx: &mut AcceptContext<'_, '_, S>,
     ) -> bool {
@@ -472,6 +470,7 @@ impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
         Allow(Target::Static),
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
+        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
     ]);
@@ -480,7 +479,7 @@ impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
         "https://doc.rust-lang.org/reference/abi.html#the-link_section-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
@@ -534,7 +533,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for StdInternalSymbolParser {
         Allow(Target::Static),
         Allow(Target::ForeignStatic),
     ]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcStdInternalSymbol;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::StdInternalSymbol;
 }
 
 pub(crate) struct LinkOrdinalParser;
@@ -553,7 +552,7 @@ impl<S: Stage> SingleAttributeParser<S> for LinkOrdinalParser {
         "https://doc.rust-lang.org/reference/items/external-blocks.html#the-link_ordinal-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ordinal = parse_single_integer(cx, args)?;
 
         // According to the table at
@@ -589,12 +588,12 @@ impl<S: Stage> SingleAttributeParser<S> for LinkageParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
+        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
         Allow(Target::Static),
         Allow(Target::ForeignStatic),
         Allow(Target::ForeignFn),
-        Warn(Target::Method(MethodKind::Trait { body: false })), // Not inherited
     ]);
 
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: [
@@ -609,7 +608,7 @@ impl<S: Stage> SingleAttributeParser<S> for LinkageParser {
         "weak_odr",
     ]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(name_value) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, Some(sym::linkage));
             return None;
@@ -661,21 +660,3 @@ impl<S: Stage> SingleAttributeParser<S> for LinkageParser {
         Some(AttributeKind::Linkage(linkage, cx.attr_span))
     }
 }
-
-pub(crate) struct NeedsAllocatorParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for NeedsAllocatorParser {
-    const PATH: &[Symbol] = &[sym::needs_allocator];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::NeedsAllocator;
-}
-
-pub(crate) struct CompilerBuiltinsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for CompilerBuiltinsParser {
-    const PATH: &[Symbol] = &[sym::compiler_builtins];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::CompilerBuiltins;
-}

compiler/rustc_attr_parsing/src/attributes/lint_helpers.rs

@@ -11,7 +11,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for AsPtrParser {
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
     ]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcAsPtr;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::AsPtr;
 }
 
 pub(crate) struct PubTransparentParser;
@@ -23,7 +23,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for PubTransparentParser {
         Allow(Target::Enum),
         Allow(Target::Union),
     ]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcPubTransparent;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::PubTransparent;
 }
 
 pub(crate) struct PassByValueParser;
@@ -35,7 +35,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for PassByValueParser {
         Allow(Target::Enum),
         Allow(Target::TyAlias),
     ]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcPassByValue;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::PassByValue;
 }
 
 pub(crate) struct RustcShouldNotBeCalledOnConstItems;

compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs

@@ -1,7 +1,8 @@
-use rustc_hir::attrs::{CollapseMacroDebuginfo, MacroUseArgs};
+use rustc_errors::DiagArgValue;
-use rustc_session::lint::builtin::INVALID_MACRO_EXPORT_ARGUMENTS;
+use rustc_hir::attrs::MacroUseArgs;
 
 use super::prelude::*;
+use crate::session_diagnostics::IllFormedAttributeInputLint;
 
 pub(crate) struct MacroEscapeParser;
 impl<S: Stage> NoArgsAttributeParser<S> for MacroEscapeParser {
@@ -99,8 +100,15 @@ impl<S: Stage> AttributeParser<S> for MacroUseParser {
                         }
                     }
                 }
-                ArgParser::NameValue(nv) => {
+                ArgParser::NameValue(_) => {
-                    cx.expected_list_or_no_args(nv.args_span());
+                    let suggestions = cx.suggestions();
+                    cx.emit_err(IllFormedAttributeInputLint {
+                        num_suggestions: suggestions.len(),
+                        suggestions: DiagArgValue::StrListSepByAnd(
+                            suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                        ),
+                        span,
+                    });
                 }
             }
         },
@@ -139,79 +147,45 @@ impl<S: Stage> SingleAttributeParser<S> for MacroExportParser {
         Error(Target::Crate),
     ]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let local_inner_macros = match args {
             ArgParser::NoArgs => false,
             ArgParser::List(list) => {
                 let Some(l) = list.single() else {
-                    cx.warn_ill_formed_attribute_input(INVALID_MACRO_EXPORT_ARGUMENTS);
+                    let span = cx.attr_span;
+                    let suggestions = cx.suggestions();
+                    cx.emit_lint(
+                        AttributeLintKind::InvalidMacroExportArguments { suggestions },
+                        span,
+                    );
                     return None;
                 };
                 match l.meta_item().and_then(|i| i.path().word_sym()) {
                     Some(sym::local_inner_macros) => true,
                     _ => {
-                        cx.warn_ill_formed_attribute_input(INVALID_MACRO_EXPORT_ARGUMENTS);
+                        let span = cx.attr_span;
+                        let suggestions = cx.suggestions();
+                        cx.emit_lint(
+                            AttributeLintKind::InvalidMacroExportArguments { suggestions },
+                            span,
+                        );
                         return None;
                     }
                 }
             }
-            ArgParser::NameValue(nv) => {
+            ArgParser::NameValue(_) => {
-                cx.expected_list_or_no_args(nv.args_span());
+                let span = cx.attr_span;
+                let suggestions = cx.suggestions();
+                cx.emit_err(IllFormedAttributeInputLint {
+                    num_suggestions: suggestions.len(),
+                    suggestions: DiagArgValue::StrListSepByAnd(
+                        suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                    ),
+                    span,
+                });
                 return None;
             }
         };
         Some(AttributeKind::MacroExport { span: cx.attr_span, local_inner_macros })
     }
 }
-
-pub(crate) struct CollapseDebugInfoParser;
-
-impl<S: Stage> SingleAttributeParser<S> for CollapseDebugInfoParser {
-    const PATH: &[Symbol] = &[sym::collapse_debuginfo];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const TEMPLATE: AttributeTemplate = template!(
-        List: &["no", "external", "yes"],
-        "https://doc.rust-lang.org/reference/attributes/debugger.html#the-collapse_debuginfo-attribute"
-    );
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::MacroDef)]);
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
-            return None;
-        };
-        let Some(single) = list.single() else {
-            cx.expected_single_argument(list.span);
-            return None;
-        };
-        let Some(mi) = single.meta_item() else {
-            cx.unexpected_literal(single.span());
-            return None;
-        };
-        if let Err(err) = mi.args().no_args() {
-            cx.expected_no_args(err);
-        }
-        let path = mi.path().word_sym();
-        let info = match path {
-            Some(sym::yes) => CollapseMacroDebuginfo::Yes,
-            Some(sym::no) => CollapseMacroDebuginfo::No,
-            Some(sym::external) => CollapseMacroDebuginfo::External,
-            _ => {
-                cx.expected_specific_argument(mi.span(), &[sym::yes, sym::no, sym::external]);
-                return None;
-            }
-        };
-
-        Some(AttributeKind::CollapseDebugInfo(info))
-    }
-}
-
-pub(crate) struct RustcProcMacroDeclsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcProcMacroDeclsParser {
-    const PATH: &[Symbol] = &[sym::rustc_proc_macro_decls];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Static)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcProcMacroDecls;
-}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -32,34 +32,27 @@ mod prelude;
 pub(crate) mod allow_unstable;
 pub(crate) mod body;
 pub(crate) mod cfg;
+pub(crate) mod cfg_old;
 pub(crate) mod cfg_select;
-pub(crate) mod cfi_encoding;
 pub(crate) mod codegen_attrs;
 pub(crate) mod confusables;
 pub(crate) mod crate_level;
 pub(crate) mod debugger;
 pub(crate) mod deprecation;
-pub(crate) mod do_not_recommend;
-pub(crate) mod doc;
 pub(crate) mod dummy;
 pub(crate) mod inline;
-pub(crate) mod instruction_set;
 pub(crate) mod link_attrs;
 pub(crate) mod lint_helpers;
 pub(crate) mod loop_match;
 pub(crate) mod macro_attrs;
-pub(crate) mod must_not_suspend;
 pub(crate) mod must_use;
 pub(crate) mod no_implicit_prelude;
-pub(crate) mod no_link;
 pub(crate) mod non_exhaustive;
 pub(crate) mod path;
 pub(crate) mod pin_v2;
 pub(crate) mod proc_macro_attrs;
 pub(crate) mod prototype;
 pub(crate) mod repr;
-pub(crate) mod rustc_allocator;
-pub(crate) mod rustc_dump;
 pub(crate) mod rustc_internal;
 pub(crate) mod semantics;
 pub(crate) mod stability;
@@ -68,7 +61,7 @@ pub(crate) mod traits;
 pub(crate) mod transparency;
 pub(crate) mod util;
 
-type AcceptFn<T, S> = for<'sess> fn(&mut T, &mut AcceptContext<'_, 'sess, S>, &ArgParser);
+type AcceptFn<T, S> = for<'sess> fn(&mut T, &mut AcceptContext<'_, 'sess, S>, &ArgParser<'_>);
 type AcceptMapping<T, S> = &'static [(&'static [Symbol], AttributeTemplate, AcceptFn<T, S>)];
 
 /// An [`AttributeParser`] is a type which searches for syntactic attributes.
@@ -139,7 +132,7 @@ pub(crate) trait SingleAttributeParser<S: Stage>: 'static {
     const TEMPLATE: AttributeTemplate;
 
     /// Converts a single syntactical attribute to a single semantic attribute, or [`AttributeKind`]
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind>;
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind>;
 }
 
 /// Use in combination with [`SingleAttributeParser`].
@@ -288,7 +281,7 @@ impl<T: NoArgsAttributeParser<S>, S: Stage> SingleAttributeParser<S> for Without
     const ALLOWED_TARGETS: AllowedTargets = T::ALLOWED_TARGETS;
     const TEMPLATE: AttributeTemplate = template!(Word);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         if let Err(span) = args.no_args() {
             cx.expected_no_args(span);
         }
@@ -321,10 +314,10 @@ pub(crate) trait CombineAttributeParser<S: Stage>: 'static {
     const TEMPLATE: AttributeTemplate;
 
     /// Converts a single syntactical attribute to a number of elements of the semantic attribute, or [`AttributeKind`]
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item>;
+    ) -> impl IntoIterator<Item = Self::Item> + 'c;
 }
 
 /// Use in combination with [`CombineAttributeParser`].

compiler/rustc_attr_parsing/src/attributes/must_not_suspend.rs

@@ -1,35 +0,0 @@
-use super::prelude::*;
-
-pub(crate) struct MustNotSuspendParser;
-
-impl<S: Stage> SingleAttributeParser<S> for MustNotSuspendParser {
-    const PATH: &[rustc_span::Symbol] = &[sym::must_not_suspend];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Struct),
-        Allow(Target::Enum),
-        Allow(Target::Union),
-        Allow(Target::Trait),
-    ]);
-    const TEMPLATE: AttributeTemplate = template!(Word, List: &["count"]);
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let reason = match args {
-            ArgParser::NameValue(reason) => match reason.value_as_str() {
-                Some(val) => Some(val),
-                None => {
-                    cx.expected_nv_or_no_args(reason.value_span);
-                    return None;
-                }
-            },
-            ArgParser::NoArgs => None,
-            ArgParser::List(list) => {
-                cx.expected_nv_or_no_args(list.span);
-                return None;
-            }
-        };
-
-        Some(AttributeKind::MustNotSupend { reason })
-    }
-}

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -1,4 +1,7 @@
+use rustc_errors::DiagArgValue;
+
 use super::prelude::*;
+use crate::session_diagnostics::IllFormedAttributeInputLint;
 
 pub(crate) struct MustUseParser;
 
@@ -26,7 +29,7 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
         "https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         Some(AttributeKind::MustUse {
             span: cx.attr_span,
             reason: match args {
@@ -41,8 +44,15 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
                     };
                     Some(value_str)
                 }
-                ArgParser::List(list) => {
+                ArgParser::List(_) => {
-                    cx.expected_nv_or_no_args(list.span);
+                    let suggestions = cx.suggestions();
+                    cx.emit_err(IllFormedAttributeInputLint {
+                        num_suggestions: suggestions.len(),
+                        suggestions: DiagArgValue::StrListSepByAnd(
+                            suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                        ),
+                        span: cx.attr_span,
+                    });
                     return None;
                 }
             },

compiler/rustc_attr_parsing/src/attributes/no_link.rs

@@ -1,14 +0,0 @@
-use super::prelude::*;
-
-pub(crate) struct NoLinkParser;
-impl<S: Stage> NoArgsAttributeParser<S> for NoLinkParser {
-    const PATH: &[Symbol] = &[sym::no_link];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::ExternCrate),
-        Warn(Target::Field),
-        Warn(Target::Arm),
-        Warn(Target::MacroDef),
-    ]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::NoLink;
-}

compiler/rustc_attr_parsing/src/attributes/path.rs

@@ -13,7 +13,7 @@ impl<S: Stage> SingleAttributeParser<S> for PathParser {
         "https://doc.rust-lang.org/reference/items/modules.html#the-path-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;

compiler/rustc_attr_parsing/src/attributes/prelude.rs

@@ -4,6 +4,8 @@ pub(super) use rustc_feature::{AttributeTemplate, template};
 #[doc(hidden)]
 pub(super) use rustc_hir::attrs::AttributeKind;
 #[doc(hidden)]
+pub(super) use rustc_hir::lints::AttributeLintKind;
+#[doc(hidden)]
 pub(super) use rustc_hir::{MethodKind, Target};
 #[doc(hidden)]
 pub(super) use rustc_span::{DUMMY_SP, Ident, Span, Symbol, sym};

compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs

@@ -1,6 +1,3 @@
-use rustc_hir::lints::AttributeLintKind;
-use rustc_session::lint::builtin::AMBIGUOUS_DERIVE_HELPERS;
-
 use super::prelude::*;
 
 const PROC_MACRO_ALLOWED_TARGETS: AllowedTargets =
@@ -33,7 +30,7 @@ impl<S: Stage> SingleAttributeParser<S> for ProcMacroDeriveParser {
         "https://doc.rust-lang.org/reference/procedural-macros.html#derive-macros"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let (trait_name, helper_attrs) = parse_derive_like(cx, args, true)?;
         Some(AttributeKind::ProcMacroDerive {
             trait_name: trait_name.expect("Trait name is mandatory, so it is present"),
@@ -52,7 +49,7 @@ impl<S: Stage> SingleAttributeParser<S> for RustcBuiltinMacroParser {
     const TEMPLATE: AttributeTemplate =
         template!(List: &["TraitName", "TraitName, attributes(name1, name2, ...)"]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let (builtin_name, helper_attrs) = parse_derive_like(cx, args, false)?;
         Some(AttributeKind::RustcBuiltinMacro { builtin_name, helper_attrs, span: cx.attr_span })
     }
@@ -60,7 +57,7 @@ impl<S: Stage> SingleAttributeParser<S> for RustcBuiltinMacroParser {
 
 fn parse_derive_like<S: Stage>(
     cx: &mut AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &ArgParser<'_>,
     trait_name_mandatory: bool,
 ) -> Option<(Option<Symbol>, ThinVec<Symbol>)> {
     let Some(list) = args.list() else {
@@ -68,7 +65,7 @@ fn parse_derive_like<S: Stage>(
         if args.no_args().is_ok() && !trait_name_mandatory {
             return Some((None, ThinVec::new()));
         }
-        cx.expected_list(cx.attr_span, args);
+        cx.expected_list(cx.attr_span);
         return None;
     };
     let mut items = list.mixed();
@@ -99,7 +96,7 @@ fn parse_derive_like<S: Stage>(
     let mut attributes = ThinVec::new();
     if let Some(attrs) = items.next() {
         let Some(attr_list) = attrs.meta_item() else {
-            cx.unexpected_literal(attrs.span());
+            cx.expected_list(attrs.span());
             return None;
         };
         if !attr_list.path().word_is(sym::attributes) {
@@ -107,7 +104,7 @@ fn parse_derive_like<S: Stage>(
             return None;
         }
         let Some(attr_list) = attr_list.args().list() else {
-            cx.expected_list(attrs.span(), attr_list.args());
+            cx.expected_list(attrs.span());
             return None;
         };
 
@@ -129,13 +126,6 @@ fn parse_derive_like<S: Stage>(
                 cx.expected_identifier(ident.span);
                 return None;
             }
-            if rustc_feature::is_builtin_attr_name(ident.name) {
-                cx.emit_lint(
-                    AMBIGUOUS_DERIVE_HELPERS,
-                    AttributeLintKind::AmbiguousDeriveHelpers,
-                    ident.span,
-                );
-            }
             attributes.push(ident.name);
         }
     }

compiler/rustc_attr_parsing/src/attributes/prototype.rs

@@ -25,9 +25,9 @@ impl<S: Stage> SingleAttributeParser<S> for CustomMirParser {
 
     const TEMPLATE: AttributeTemplate = template!(List: &[r#"dialect = "...", phase = "...""#]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
+            cx.expected_list(cx.attr_span);
             return None;
         };
 
@@ -46,8 +46,9 @@ impl<S: Stage> SingleAttributeParser<S> for CustomMirParser {
                 extract_value(cx, sym::dialect, arg, meta_item.span(), &mut dialect, &mut failed);
             } else if let Some(arg) = meta_item.word_is(sym::phase) {
                 extract_value(cx, sym::phase, arg, meta_item.span(), &mut phase, &mut failed);
-            } else if let Some(..) = meta_item.path().word() {
+            } else if let Some(word) = meta_item.path().word() {
-                cx.expected_specific_argument(meta_item.span(), &[sym::dialect, sym::phase]);
+                let word = word.to_string();
+                cx.unknown_key(meta_item.span(), word, &["dialect", "phase"]);
                 failed = true;
             } else {
                 cx.expected_name_value(meta_item.span(), None);
@@ -69,7 +70,7 @@ impl<S: Stage> SingleAttributeParser<S> for CustomMirParser {
 fn extract_value<S: Stage>(
     cx: &mut AcceptContext<'_, '_, S>,
     key: Symbol,
-    arg: &ArgParser,
+    arg: &ArgParser<'_>,
     span: Span,
     out_val: &mut Option<(Symbol, Span)>,
     failed: &mut bool,

compiler/rustc_attr_parsing/src/attributes/repr.rs

@@ -26,14 +26,14 @@ impl<S: Stage> CombineAttributeParser<S> for ReprParser {
         "https://doc.rust-lang.org/reference/type-layout.html#representations"
     );
 
-    fn extend(
+    fn extend<'c>(
-        cx: &mut AcceptContext<'_, '_, S>,
+        cx: &'c mut AcceptContext<'_, '_, S>,
-        args: &ArgParser,
+        args: &'c ArgParser<'_>,
-    ) -> impl IntoIterator<Item = Self::Item> {
+    ) -> impl IntoIterator<Item = Self::Item> + 'c {
         let mut reprs = Vec::new();
 
         let Some(list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
+            cx.expected_list(cx.attr_span);
             return reprs;
         };
 
@@ -98,7 +98,10 @@ fn int_type_of_word(s: Symbol) -> Option<IntType> {
     }
 }
 
-fn parse_repr<S: Stage>(cx: &AcceptContext<'_, '_, S>, param: &MetaItemParser) -> Option<ReprAttr> {
+fn parse_repr<S: Stage>(
+    cx: &AcceptContext<'_, '_, S>,
+    param: &MetaItemParser<'_>,
+) -> Option<ReprAttr> {
     use ReprAttr::*;
 
     // FIXME(jdonszelmann): invert the parsing here to match on the word first and then the
@@ -189,7 +192,7 @@ enum AlignKind {
 
 fn parse_repr_align<S: Stage>(
     cx: &AcceptContext<'_, '_, S>,
-    list: &MetaItemListParser,
+    list: &MetaItemListParser<'_>,
     param_span: Span,
     align_kind: AlignKind,
 ) -> Option<ReprAttr> {
@@ -272,13 +275,17 @@ fn parse_alignment(node: &LitKind) -> Result<Align, &'static str> {
 pub(crate) struct AlignParser(Option<(Align, Span)>);
 
 impl AlignParser {
-    const PATH: &[Symbol] = &[sym::rustc_align];
+    const PATH: &'static [Symbol] = &[sym::rustc_align];
     const TEMPLATE: AttributeTemplate = template!(List: &["<alignment in bytes>"]);
 
-    fn parse<S: Stage>(&mut self, cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) {
+    fn parse<'c, S: Stage>(
+        &mut self,
+        cx: &'c mut AcceptContext<'_, '_, S>,
+        args: &'c ArgParser<'_>,
+    ) {
         match args {
             ArgParser::NoArgs | ArgParser::NameValue(_) => {
-                cx.expected_list(cx.attr_span, args);
+                cx.expected_list(cx.attr_span);
             }
             ArgParser::List(list) => {
                 let Some(align) = list.single() else {
@@ -315,7 +322,7 @@ impl<S: Stage> AttributeParser<S> for AlignParser {
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: false })), // `#[align]` is inherited from trait methods
+        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::ForeignFn),
     ]);
 
@@ -329,10 +336,14 @@ impl<S: Stage> AttributeParser<S> for AlignParser {
 pub(crate) struct AlignStaticParser(AlignParser);
 
 impl AlignStaticParser {
-    const PATH: &[Symbol] = &[sym::rustc_align_static];
+    const PATH: &'static [Symbol] = &[sym::rustc_align_static];
     const TEMPLATE: AttributeTemplate = AlignParser::TEMPLATE;
 
-    fn parse<S: Stage>(&mut self, cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) {
+    fn parse<'c, S: Stage>(
+        &mut self,
+        cx: &'c mut AcceptContext<'_, '_, S>,
+        args: &'c ArgParser<'_>,
+    ) {
         self.0.parse(cx, args)
     }
 }

compiler/rustc_attr_parsing/src/attributes/rustc_allocator.rs

@@ -1,60 +0,0 @@
-use super::prelude::*;
-
-pub(crate) struct RustcAllocatorParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcAllocatorParser {
-    const PATH: &[Symbol] = &[sym::rustc_allocator];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets =
-        AllowedTargets::AllowList(&[Allow(Target::Fn), Allow(Target::ForeignFn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcAllocator;
-}
-
-pub(crate) struct RustcAllocatorZeroedParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcAllocatorZeroedParser {
-    const PATH: &[Symbol] = &[sym::rustc_allocator_zeroed];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets =
-        AllowedTargets::AllowList(&[Allow(Target::Fn), Allow(Target::ForeignFn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcAllocatorZeroed;
-}
-
-pub(crate) struct RustcAllocatorZeroedVariantParser;
-
-impl<S: Stage> SingleAttributeParser<S> for RustcAllocatorZeroedVariantParser {
-    const PATH: &[Symbol] = &[sym::rustc_allocator_zeroed_variant];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets =
-        AllowedTargets::AllowList(&[Allow(Target::Fn), Allow(Target::ForeignFn)]);
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "function");
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(name) = args.name_value().and_then(NameValueParser::value_as_str) else {
-            cx.expected_name_value(cx.attr_span, None);
-            return None;
-        };
-
-        Some(AttributeKind::RustcAllocatorZeroedVariant { name })
-    }
-}
-
-pub(crate) struct RustcDeallocatorParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDeallocatorParser {
-    const PATH: &[Symbol] = &[sym::rustc_deallocator];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets =
-        AllowedTargets::AllowList(&[Allow(Target::Fn), Allow(Target::ForeignFn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcDeallocator;
-}
-
-pub(crate) struct RustcReallocatorParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcReallocatorParser {
-    const PATH: &[Symbol] = &[sym::rustc_reallocator];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets =
-        AllowedTargets::AllowList(&[Allow(Target::Fn), Allow(Target::ForeignFn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcReallocator;
-}

compiler/rustc_attr_parsing/src/attributes/rustc_dump.rs

@@ -1,62 +0,0 @@
-use rustc_hir::Target;
-use rustc_hir::attrs::AttributeKind;
-use rustc_span::{Span, Symbol, sym};
-
-use crate::attributes::prelude::Allow;
-use crate::attributes::{NoArgsAttributeParser, OnDuplicate};
-use crate::context::Stage;
-use crate::target_checking::AllowedTargets;
-
-pub(crate) struct RustcDumpUserArgsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDumpUserArgsParser {
-    const PATH: &[Symbol] = &[sym::rustc_dump_user_args];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcDumpUserArgs;
-}
-
-pub(crate) struct RustcDumpDefParentsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDumpDefParentsParser {
-    const PATH: &[Symbol] = &[sym::rustc_dump_def_parents];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcDumpDefParents;
-}
-
-pub(crate) struct RustcDumpItemBoundsParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDumpItemBoundsParser {
-    const PATH: &[Symbol] = &[sym::rustc_dump_item_bounds];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::AssocTy)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcDumpItemBounds;
-}
-
-pub(crate) struct RustcDumpPredicatesParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDumpPredicatesParser {
-    const PATH: &[Symbol] = &[sym::rustc_dump_predicates];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Struct),
-        Allow(Target::Enum),
-        Allow(Target::Union),
-        Allow(Target::Trait),
-        Allow(Target::AssocTy),
-    ]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcDumpPredicates;
-}
-
-pub(crate) struct RustcDumpVtableParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDumpVtableParser {
-    const PATH: &[Symbol] = &[sym::rustc_dump_vtable];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Impl { of_trait: true }),
-        Allow(Target::TyAlias),
-    ]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcDumpVtable;
-}

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -1,7 +1,6 @@
 use std::num::NonZero;
 
 use rustc_errors::ErrorGuaranteed;
-use rustc_hir::target::GenericParamKind;
 use rustc_hir::{
     DefaultBodyStability, MethodKind, PartialConstStability, Stability, StabilityLevel,
     StableSince, Target, UnstableReason, VERSION_PLACEHOLDER,
@@ -9,7 +8,7 @@ use rustc_hir::{
 
 use super::prelude::*;
 use super::util::parse_version;
-use crate::session_diagnostics::{self};
+use crate::session_diagnostics::{self, UnsupportedLiteralReason};
 
 macro_rules! reject_outside_std {
     ($cx: ident) => {
@@ -44,7 +43,7 @@ const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
     Allow(Target::TyAlias),
     Allow(Target::Variant),
     Allow(Target::Field),
-    Allow(Target::GenericParam { kind: GenericParamKind::Type, has_default: true }),
+    Allow(Target::Param),
     Allow(Target::Static),
     Allow(Target::ForeignFn),
     Allow(Target::ForeignStatic),
@@ -173,7 +172,7 @@ impl<S: Stage> AttributeParser<S> for BodyStabilityParser {
     fn finalize(self, _cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
         let (stability, span) = self.stability?;
 
-        Some(AttributeKind::RustcBodyStability { stability, span })
+        Some(AttributeKind::BodyStability { stability, span })
     }
 }
 
@@ -185,7 +184,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for ConstStabilityIndirectParser {
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
     ]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcConstStabilityIndirect;
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::ConstStabilityIndirect;
 }
 
 #[derive(Default)]
@@ -244,20 +243,7 @@ impl<S: Stage> AttributeParser<S> for ConstStabilityParser {
             this.promotable = true;
         }),
     ];
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
+    const ALLOWED_TARGETS: AllowedTargets = ALLOWED_TARGETS;
-        Allow(Target::Fn),
-        Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: true })),
-        Allow(Target::Impl { of_trait: false }),
-        Allow(Target::Impl { of_trait: true }),
-        Allow(Target::Use), // FIXME I don't think this does anything?
-        Allow(Target::Const),
-        Allow(Target::AssocConst),
-        Allow(Target::Trait),
-        Allow(Target::Static),
-        Allow(Target::Crate),
-    ]);
 
     fn finalize(mut self, cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
         if self.promotable {
@@ -271,7 +257,7 @@ impl<S: Stage> AttributeParser<S> for ConstStabilityParser {
 
         let (stability, span) = self.stability?;
 
-        Some(AttributeKind::RustcConstStability { stability, span })
+        Some(AttributeKind::ConstStability { stability, span })
     }
 }
 
@@ -281,7 +267,7 @@ impl<S: Stage> AttributeParser<S> for ConstStabilityParser {
 /// `name = value`
 fn insert_value_into_option_or_error<S: Stage>(
     cx: &AcceptContext<'_, '_, S>,
-    param: &MetaItemParser,
+    param: &MetaItemParser<'_>,
     item: &mut Option<Symbol>,
     name: Ident,
 ) -> Option<()> {
@@ -303,20 +289,25 @@ fn insert_value_into_option_or_error<S: Stage>(
 /// its stability information.
 pub(crate) fn parse_stability<S: Stage>(
     cx: &AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &ArgParser<'_>,
 ) -> Option<(Symbol, StabilityLevel)> {
     let mut feature = None;
     let mut since = None;
 
     let ArgParser::List(list) = args else {
-        cx.expected_list(cx.attr_span, args);
+        cx.expected_list(cx.attr_span);
         return None;
     };
 
     for param in list.mixed() {
         let param_span = param.span();
         let Some(param) = param.meta_item() else {
-            cx.unexpected_literal(param.span());
+            cx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: param_span,
+                reason: UnsupportedLiteralReason::Generic,
+                is_bytestr: false,
+                start_point_span: cx.sess().source_map().start_point(param_span),
+            });
             return None;
         };
 
@@ -329,7 +320,11 @@ pub(crate) fn parse_stability<S: Stage>(
                 insert_value_into_option_or_error(cx, &param, &mut since, word.unwrap())?
             }
             _ => {
-                cx.expected_specific_argument(param_span, &[sym::feature, sym::since]);
+                cx.emit_err(session_diagnostics::UnknownMetaItem {
+                    span: param_span,
+                    item: param.path().to_string(),
+                    expected: &["feature", "since"],
+                });
                 return None;
             }
         }
@@ -370,7 +365,7 @@ pub(crate) fn parse_stability<S: Stage>(
 /// attribute, and return the feature name and its stability information.
 pub(crate) fn parse_unstability<S: Stage>(
     cx: &AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &ArgParser<'_>,
 ) -> Option<(Symbol, StabilityLevel)> {
     let mut feature = None;
     let mut reason = None;
@@ -381,13 +376,18 @@ pub(crate) fn parse_unstability<S: Stage>(
     let mut old_name = None;
 
     let ArgParser::List(list) = args else {
-        cx.expected_list(cx.attr_span, args);
+        cx.expected_list(cx.attr_span);
         return None;
     };
 
     for param in list.mixed() {
         let Some(param) = param.meta_item() else {
-            cx.unexpected_literal(param.span());
+            cx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: param.span(),
+                reason: UnsupportedLiteralReason::Generic,
+                is_bytestr: false,
+                start_point_span: cx.sess().source_map().start_point(param.span()),
+            });
             return None;
         };
 
@@ -436,17 +436,11 @@ pub(crate) fn parse_unstability<S: Stage>(
                 insert_value_into_option_or_error(cx, &param, &mut old_name, word.unwrap())?
             }
             _ => {
-                cx.expected_specific_argument(
+                cx.emit_err(session_diagnostics::UnknownMetaItem {
-                    param.span(),
+                    span: param.span(),
-                    &[
+                    item: param.path().to_string(),
-                        sym::feature,
+                    expected: &["feature", "reason", "issue", "soft", "implied_by", "old_name"],
-                        sym::reason,
+                });
-                        sym::issue,
-                        sym::soft,
-                        sym::implied_by,
-                        sym::old_name,
-                    ],
-                );
                 return None;
             }
         }

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -1,6 +1,3 @@
-use rustc_hir::attrs::RustcAbiAttrKind;
-use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
-
 use super::prelude::*;
 
 pub(crate) struct IgnoreParser;
@@ -16,20 +13,27 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
         "https://doc.rust-lang.org/reference/attributes/testing.html#the-ignore-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         Some(AttributeKind::Ignore {
             span: cx.attr_span,
             reason: match args {
                 ArgParser::NoArgs => None,
                 ArgParser::NameValue(name_value) => {
                     let Some(str_value) = name_value.value_as_str() else {
-                        cx.warn_ill_formed_attribute_input(ILL_FORMED_ATTRIBUTE_INPUT);
+                        let suggestions = cx.suggestions();
+                        let span = cx.attr_span;
+                        cx.emit_lint(
+                            AttributeLintKind::IllFormedAttributeInput { suggestions },
+                            span,
+                        );
                         return None;
                     };
                     Some(str_value)
                 }
                 ArgParser::List(_) => {
-                    cx.warn_ill_formed_attribute_input(ILL_FORMED_ATTRIBUTE_INPUT);
+                    let suggestions = cx.suggestions();
+                    let span = cx.attr_span;
+                    cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                     return None;
                 }
             },
@@ -50,7 +54,7 @@ impl<S: Stage> SingleAttributeParser<S> for ShouldPanicParser {
         "https://doc.rust-lang.org/reference/attributes/testing.html#the-should_panic-attribute"
     );
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         Some(AttributeKind::ShouldPanic {
             span: cx.attr_span,
             reason: match args {
@@ -92,201 +96,3 @@ impl<S: Stage> SingleAttributeParser<S> for ShouldPanicParser {
         })
     }
 }
-
-pub(crate) struct RustcVarianceParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcVarianceParser {
-    const PATH: &[Symbol] = &[sym::rustc_variance];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Struct),
-        Allow(Target::Enum),
-        Allow(Target::Union),
-    ]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcVariance;
-}
-
-pub(crate) struct RustcVarianceOfOpaquesParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcVarianceOfOpaquesParser {
-    const PATH: &[Symbol] = &[sym::rustc_variance_of_opaques];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcVarianceOfOpaques;
-}
-
-pub(crate) struct ReexportTestHarnessMainParser;
-
-impl<S: Stage> SingleAttributeParser<S> for ReexportTestHarnessMainParser {
-    const PATH: &[Symbol] = &[sym::reexport_test_harness_main];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(nv) = args.name_value() else {
-            cx.expected_name_value(
-                args.span().unwrap_or(cx.inner_span),
-                Some(sym::reexport_test_harness_main),
-            );
-            return None;
-        };
-
-        let Some(name) = nv.value_as_str() else {
-            cx.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
-            return None;
-        };
-
-        Some(AttributeKind::ReexportTestHarnessMain(name))
-    }
-}
-
-pub(crate) struct RustcAbiParser;
-
-impl<S: Stage> SingleAttributeParser<S> for RustcAbiParser {
-    const PATH: &[Symbol] = &[sym::rustc_abi];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const TEMPLATE: AttributeTemplate = template!(OneOf: &[sym::debug, sym::assert_eq]);
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::TyAlias),
-        Allow(Target::Fn),
-        Allow(Target::ForeignFn),
-        Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::Trait { body: true })),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
-        Allow(Target::Method(MethodKind::TraitImpl)),
-    ]);
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(args) = args.list() else {
-            cx.expected_specific_argument_and_list(cx.attr_span, &[sym::assert_eq, sym::debug]);
-            return None;
-        };
-
-        let Some(arg) = args.single() else {
-            cx.expected_single_argument(cx.attr_span);
-            return None;
-        };
-
-        let fail_incorrect_argument =
-            |span| cx.expected_specific_argument(span, &[sym::assert_eq, sym::debug]);
-
-        let Some(arg) = arg.meta_item() else {
-            fail_incorrect_argument(args.span);
-            return None;
-        };
-
-        let kind: RustcAbiAttrKind = match arg.path().word_sym() {
-            Some(sym::assert_eq) => RustcAbiAttrKind::AssertEq,
-            Some(sym::debug) => RustcAbiAttrKind::Debug,
-            None | Some(_) => {
-                fail_incorrect_argument(arg.span());
-                return None;
-            }
-        };
-
-        Some(AttributeKind::RustcAbi { attr_span: cx.attr_span, kind })
-    }
-}
-
-pub(crate) struct RustcDelayedBugFromInsideQueryParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcDelayedBugFromInsideQueryParser {
-    const PATH: &[Symbol] = &[sym::rustc_delayed_bug_from_inside_query];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcDelayedBugFromInsideQuery;
-}
-
-pub(crate) struct RustcEvaluateWhereClausesParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcEvaluateWhereClausesParser {
-    const PATH: &[Symbol] = &[sym::rustc_evaluate_where_clauses];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Fn),
-        Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::Trait { body: true })),
-        Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
-    ]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcEvaluateWhereClauses;
-}
-
-pub(crate) struct RustcOutlivesParser;
-
-impl<S: Stage> NoArgsAttributeParser<S> for RustcOutlivesParser {
-    const PATH: &[Symbol] = &[sym::rustc_outlives];
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Struct),
-        Allow(Target::Enum),
-        Allow(Target::Union),
-        Allow(Target::TyAlias),
-    ]);
-    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcOutlives;
-}
-
-pub(crate) struct TestRunnerParser;
-
-impl<S: Stage> SingleAttributeParser<S> for TestRunnerParser {
-    const PATH: &[Symbol] = &[sym::test_runner];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
-    const TEMPLATE: AttributeTemplate = template!(List: &["path"]);
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(list) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
-            return None;
-        };
-
-        let Some(single) = list.single() else {
-            cx.expected_single_argument(list.span);
-            return None;
-        };
-
-        let Some(meta) = single.meta_item() else {
-            cx.unexpected_literal(single.span());
-            return None;
-        };
-
-        Some(AttributeKind::TestRunner(meta.path().0.clone()))
-    }
-}
-
-pub(crate) struct RustcTestMarkerParser;
-
-impl<S: Stage> SingleAttributeParser<S> for RustcTestMarkerParser {
-    const PATH: &[Symbol] = &[sym::rustc_test_marker];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
-    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
-        Allow(Target::Const),
-        Allow(Target::Fn),
-        Allow(Target::Static),
-    ]);
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "test_path");
-
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
-        let Some(name_value) = args.name_value() else {
-            cx.expected_name_value(cx.attr_span, Some(sym::rustc_test_marker));
-            return None;
-        };
-
-        let Some(value_str) = name_value.value_as_str() else {
-            cx.expected_string_literal(name_value.value_span, None);
-            return None;
-        };
-
-        if value_str.as_str().trim().is_empty() {
-            cx.expected_non_empty_string_literal(name_value.value_span);
-            return None;
-        }
-
-        Some(AttributeKind::RustcTestMarker(value_str))
-    }
-}

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -18,11 +18,11 @@ impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
 
     const TEMPLATE: AttributeTemplate = template!(List: &["array, boxed_slice"]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let mut array = false;
         let mut boxed_slice = false;
         let Some(args) = args.list() else {
-            cx.expected_list(cx.attr_span, args);
+            cx.expected_list(cx.attr_span);
             return None;
         };
         if args.is_empty() {
@@ -50,11 +50,7 @@ impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
                 cx.duplicate_key(arg.span(), key);
             }
         }
-        Some(AttributeKind::RustcSkipDuringMethodDispatch {
+        Some(AttributeKind::SkipDuringMethodDispatch { array, boxed_slice, span: cx.attr_span })
-            array,
-            boxed_slice,
-            span: cx.attr_span,
-        })
     }
 }
 
@@ -63,7 +59,16 @@ impl<S: Stage> NoArgsAttributeParser<S> for ParenSugarParser {
     const PATH: &[Symbol] = &[sym::rustc_paren_sugar];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcParenSugar;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::ParenSugar;
+}
+
+pub(crate) struct TypeConstParser;
+impl<S: Stage> NoArgsAttributeParser<S> for TypeConstParser {
+    const PATH: &[Symbol] = &[sym::type_const];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[Allow(Target::Const), Allow(Target::AssocConst)]);
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::TypeConst;
 }
 
 // Markers
@@ -86,15 +91,15 @@ impl<S: Stage> NoArgsAttributeParser<S> for DenyExplicitImplParser {
     const PATH: &[Symbol] = &[sym::rustc_deny_explicit_impl];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcDenyExplicitImpl;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::DenyExplicitImpl;
 }
 
-pub(crate) struct DynIncompatibleTraitParser;
+pub(crate) struct DoNotImplementViaObjectParser;
-impl<S: Stage> NoArgsAttributeParser<S> for DynIncompatibleTraitParser {
+impl<S: Stage> NoArgsAttributeParser<S> for DoNotImplementViaObjectParser {
-    const PATH: &[Symbol] = &[sym::rustc_dyn_incompatible_trait];
+    const PATH: &[Symbol] = &[sym::rustc_do_not_implement_via_object];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcDynIncompatibleTrait;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::DoNotImplementViaObject;
 }
 
 // Specialization
@@ -104,7 +109,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for SpecializationTraitParser {
     const PATH: &[Symbol] = &[sym::rustc_specialization_trait];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcSpecializationTrait;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::SpecializationTrait;
 }
 
 pub(crate) struct UnsafeSpecializationMarkerParser;
@@ -112,7 +117,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for UnsafeSpecializationMarkerParser {
     const PATH: &[Symbol] = &[sym::rustc_unsafe_specialization_marker];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcUnsafeSpecializationMarker;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::UnsafeSpecializationMarker;
 }
 
 // Coherence
@@ -122,7 +127,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for CoinductiveParser {
     const PATH: &[Symbol] = &[sym::rustc_coinductive];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Trait)]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcCoinductive;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::Coinductive;
 }
 
 pub(crate) struct AllowIncoherentImplParser;
@@ -131,7 +136,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for AllowIncoherentImplParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const ALLOWED_TARGETS: AllowedTargets =
         AllowedTargets::AllowList(&[Allow(Target::Method(MethodKind::Inherent))]);
-    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcAllowIncoherentImpl;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::AllowIncoherentImpl;
 }
 
 pub(crate) struct FundamentalParser;

compiler/rustc_attr_parsing/src/attributes/transparency.rs

@@ -4,6 +4,9 @@ use super::prelude::*;
 
 pub(crate) struct TransparencyParser;
 
+// FIXME(jdonszelmann): make these proper diagnostics
+#[allow(rustc::untranslatable_diagnostic)]
+#[allow(rustc::diagnostic_outside_of_impl)]
 impl<S: Stage> SingleAttributeParser<S> for TransparencyParser {
     const PATH: &[Symbol] = &[sym::rustc_macro_transparency];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
@@ -12,26 +15,26 @@ impl<S: Stage> SingleAttributeParser<S> for TransparencyParser {
     });
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::MacroDef)]);
     const TEMPLATE: AttributeTemplate =
-        template!(NameValueStr: ["transparent", "semiopaque", "opaque"]);
+        template!(NameValueStr: ["transparent", "semitransparent", "opaque"]);
 
-    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
             cx.expected_name_value(cx.attr_span, None);
             return None;
         };
         match nv.value_as_str() {
             Some(sym::transparent) => Some(Transparency::Transparent),
-            Some(sym::semiopaque) => Some(Transparency::SemiOpaque),
+            Some(sym::semiopaque | sym::semitransparent) => Some(Transparency::SemiOpaque),
             Some(sym::opaque) => Some(Transparency::Opaque),
             Some(_) => {
                 cx.expected_specific_argument_strings(
                     nv.value_span,
-                    &[sym::transparent, sym::semiopaque, sym::opaque],
+                    &[sym::transparent, sym::semitransparent, sym::opaque],
                 );
                 None
             }
             None => None,
         }
-        .map(AttributeKind::RustcMacroTransparency)
+        .map(AttributeKind::MacroTransparency)
     }
 }

compiler/rustc_attr_parsing/src/attributes/util.rs

@@ -5,7 +5,7 @@ use rustc_ast::attr::AttributeExt;
 use rustc_feature::is_builtin_attr_name;
 use rustc_hir::RustcVersion;
 use rustc_hir::limit::Limit;
-use rustc_span::Symbol;
+use rustc_span::{Symbol, sym};
 
 use crate::context::{AcceptContext, Stage};
 use crate::parser::{ArgParser, NameValueParser};
@@ -28,7 +28,38 @@ pub fn parse_version(s: Symbol) -> Option<RustcVersion> {
 }
 
 pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
-    attr.is_doc_comment().is_some() || attr.name().is_some_and(|name| is_builtin_attr_name(name))
+    attr.is_doc_comment().is_some()
+        || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
+}
+
+pub fn is_doc_alias_attrs_contain_symbol<'tcx, T: AttributeExt + 'tcx>(
+    attrs: impl Iterator<Item = &'tcx T>,
+    symbol: Symbol,
+) -> bool {
+    let doc_attrs = attrs.filter(|attr| attr.has_name(sym::doc));
+    for attr in doc_attrs {
+        let Some(values) = attr.meta_item_list() else {
+            continue;
+        };
+        let alias_values = values.iter().filter(|v| v.has_name(sym::alias));
+        for v in alias_values {
+            if let Some(nested) = v.meta_item_list() {
+                // #[doc(alias("foo", "bar"))]
+                let mut iter = nested.iter().filter_map(|item| item.lit()).map(|item| item.symbol);
+                if iter.any(|s| s == symbol) {
+                    return true;
+                }
+            } else if let Some(meta) = v.meta_item()
+                && let Some(lit) = meta.name_value_literal()
+            {
+                // #[doc(alias = "foo")]
+                if lit.symbol == symbol {
+                    return true;
+                }
+            }
+        }
+    }
+    false
 }
 
 /// Parse a single integer.
@@ -39,10 +70,10 @@ pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
 /// `args` is the parser for the attribute arguments.
 pub(crate) fn parse_single_integer<S: Stage>(
     cx: &mut AcceptContext<'_, '_, S>,
-    args: &ArgParser,
+    args: &ArgParser<'_>,
 ) -> Option<u128> {
     let Some(list) = args.list() else {
-        cx.expected_list(cx.attr_span, args);
+        cx.expected_list(cx.attr_span);
         return None;
     };
     let Some(single) = list.single() else {

compiler/rustc_attr_parsing/src/context.rs

@@ -1,80 +1,100 @@
 use std::cell::RefCell;
 use std::collections::BTreeMap;
-use std::collections::btree_map::Entry;
 use std::ops::{Deref, DerefMut};
 use std::sync::LazyLock;
 
 use private::Sealed;
-use rustc_ast::{AttrStyle, MetaItemLit, NodeId};
+use rustc_ast::{AttrStyle, CRATE_NODE_ID, MetaItemLit, NodeId};
 use rustc_errors::{Diag, Diagnostic, Level};
 use rustc_feature::{AttrSuggestionStyle, AttributeTemplate};
 use rustc_hir::attrs::AttributeKind;
-use rustc_hir::lints::AttributeLintKind;
+use rustc_hir::lints::{AttributeLint, AttributeLintKind};
-use rustc_hir::{AttrPath, HirId};
+use rustc_hir::{AttrPath, CRATE_HIR_ID, HirId};
-use rustc_parse::parser::Recovery;
 use rustc_session::Session;
-use rustc_session::lint::{Lint, LintId};
 use rustc_span::{ErrorGuaranteed, Span, Symbol};
 
 use crate::AttributeParser;
-// Glob imports to avoid big, bitrotty import lists
+use crate::attributes::allow_unstable::{
-use crate::attributes::allow_unstable::*;
+    AllowConstFnUnstableParser, AllowInternalUnstableParser, UnstableFeatureBoundParser,
-use crate::attributes::body::*;
+};
-use crate::attributes::cfi_encoding::*;
+use crate::attributes::body::CoroutineParser;
-use crate::attributes::codegen_attrs::*;
+use crate::attributes::codegen_attrs::{
-use crate::attributes::confusables::*;
+    ColdParser, CoverageParser, ExportNameParser, ForceTargetFeatureParser, NakedParser,
-use crate::attributes::crate_level::*;
+    NoMangleParser, ObjcClassParser, ObjcSelectorParser, OptimizeParser,
-use crate::attributes::debugger::*;
+    RustcPassIndirectlyInNonRusticAbisParser, SanitizeParser, TargetFeatureParser,
-use crate::attributes::deprecation::*;
+    TrackCallerParser, UsedParser,
-use crate::attributes::do_not_recommend::*;
+};
-use crate::attributes::doc::*;
+use crate::attributes::confusables::ConfusablesParser;
-use crate::attributes::dummy::*;
+use crate::attributes::crate_level::{
-use crate::attributes::inline::*;
+    CrateNameParser, MoveSizeLimitParser, NoCoreParser, NoStdParser, PatternComplexityLimitParser,
-use crate::attributes::instruction_set::*;
+    RecursionLimitParser, RustcCoherenceIsCoreParser, TypeLengthLimitParser,
-use crate::attributes::link_attrs::*;
+    WindowsSubsystemParser,
-use crate::attributes::lint_helpers::*;
+};
-use crate::attributes::loop_match::*;
+use crate::attributes::debugger::DebuggerViualizerParser;
-use crate::attributes::macro_attrs::*;
+use crate::attributes::deprecation::DeprecationParser;
-use crate::attributes::must_not_suspend::*;
+use crate::attributes::dummy::DummyParser;
-use crate::attributes::must_use::*;
+use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
-use crate::attributes::no_implicit_prelude::*;
+use crate::attributes::link_attrs::{
-use crate::attributes::no_link::*;
+    ExportStableParser, FfiConstParser, FfiPureParser, LinkNameParser, LinkOrdinalParser,
-use crate::attributes::non_exhaustive::*;
+    LinkParser, LinkSectionParser, LinkageParser, StdInternalSymbolParser,
+};
+use crate::attributes::lint_helpers::{
+    AsPtrParser, AutomaticallyDerivedParser, PassByValueParser, PubTransparentParser,
+    RustcShouldNotBeCalledOnConstItems,
+};
+use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
+use crate::attributes::macro_attrs::{
+    AllowInternalUnsafeParser, MacroEscapeParser, MacroExportParser, MacroUseParser,
+};
+use crate::attributes::must_use::MustUseParser;
+use crate::attributes::no_implicit_prelude::NoImplicitPreludeParser;
+use crate::attributes::non_exhaustive::NonExhaustiveParser;
 use crate::attributes::path::PathParser as PathAttributeParser;
-use crate::attributes::pin_v2::*;
+use crate::attributes::pin_v2::PinV2Parser;
-use crate::attributes::proc_macro_attrs::*;
+use crate::attributes::proc_macro_attrs::{
-use crate::attributes::prototype::*;
+    ProcMacroAttributeParser, ProcMacroDeriveParser, ProcMacroParser, RustcBuiltinMacroParser,
-use crate::attributes::repr::*;
+};
-use crate::attributes::rustc_allocator::*;
+use crate::attributes::prototype::CustomMirParser;
-use crate::attributes::rustc_dump::*;
+use crate::attributes::repr::{AlignParser, AlignStaticParser, ReprParser};
-use crate::attributes::rustc_internal::*;
+use crate::attributes::rustc_internal::{
-use crate::attributes::semantics::*;
+    RustcLayoutScalarValidRangeEndParser, RustcLayoutScalarValidRangeStartParser, RustcMainParser,
-use crate::attributes::stability::*;
+    RustcObjectLifetimeDefaultParser, RustcSimdMonomorphizeLaneLimitParser,
-use crate::attributes::test_attrs::*;
+};
-use crate::attributes::traits::*;
+use crate::attributes::semantics::MayDangleParser;
-use crate::attributes::transparency::*;
+use crate::attributes::stability::{
+    BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
+};
+use crate::attributes::test_attrs::{IgnoreParser, ShouldPanicParser};
+use crate::attributes::traits::{
+    AllowIncoherentImplParser, CoinductiveParser, DenyExplicitImplParser,
+    DoNotImplementViaObjectParser, FundamentalParser, MarkerParser, ParenSugarParser,
+    PointeeParser, SkipDuringMethodDispatchParser, SpecializationTraitParser, TypeConstParser,
+    UnsafeSpecializationMarkerParser,
+};
+use crate::attributes::transparency::TransparencyParser;
 use crate::attributes::{AttributeParser as _, Combine, Single, WithoutArgs};
-use crate::parser::{ArgParser, RefPathParser};
+use crate::parser::{ArgParser, PathParser};
 use crate::session_diagnostics::{
-    AttributeParseError, AttributeParseErrorReason, ParsedDescription,
+    AttributeParseError, AttributeParseErrorReason, ParsedDescription, UnknownMetaItem,
 };
 use crate::target_checking::AllowedTargets;
+
 type GroupType<S> = LazyLock<GroupTypeInner<S>>;
 
 pub(super) struct GroupTypeInner<S: Stage> {
-    pub(super) accepters: BTreeMap<&'static [Symbol], GroupTypeInnerAccept<S>>,
+    pub(super) accepters: BTreeMap<&'static [Symbol], Vec<GroupTypeInnerAccept<S>>>,
+    pub(super) finalizers: Vec<FinalizeFn<S>>,
 }
 
 pub(super) struct GroupTypeInnerAccept<S: Stage> {
     pub(super) template: AttributeTemplate,
     pub(super) accept_fn: AcceptFn<S>,
     pub(super) allowed_targets: AllowedTargets,
-    pub(super) finalizer: FinalizeFn<S>,
 }
 
-pub(crate) type AcceptFn<S> =
+type AcceptFn<S> =
-    Box<dyn for<'sess, 'a> Fn(&mut AcceptContext<'_, 'sess, S>, &ArgParser) + Send + Sync>;
+    Box<dyn for<'sess, 'a> Fn(&mut AcceptContext<'_, 'sess, S>, &ArgParser<'a>) + Send + Sync>;
-pub(crate) type FinalizeFn<S> =
+type FinalizeFn<S> =
     Box<dyn Send + Sync + Fn(&mut FinalizeContext<'_, '_, S>) -> Option<AttributeKind>>;
 
 macro_rules! attribute_parsers {
@@ -102,7 +122,8 @@ macro_rules! attribute_parsers {
         @[$stage: ty] pub(crate) static $name: ident = [$($names: ty),* $(,)?];
     ) => {
         pub(crate) static $name: GroupType<$stage> = LazyLock::new(|| {
-            let mut accepters = BTreeMap::<_, GroupTypeInnerAccept<$stage>>::new();
+            let mut accepts = BTreeMap::<_, Vec<GroupTypeInnerAccept<$stage>>>::new();
+            let mut finalizes = Vec::<FinalizeFn<$stage>>::new();
             $(
                 {
                     thread_local! {
@@ -110,29 +131,25 @@ macro_rules! attribute_parsers {
                     };
 
                     for (path, template, accept_fn) in <$names>::ATTRIBUTES {
-                        match accepters.entry(*path) {
+                        accepts.entry(*path).or_default().push(GroupTypeInnerAccept {
-                            Entry::Vacant(e) => {
+                            template: *template,
-                                e.insert(GroupTypeInnerAccept {
+                            accept_fn: Box::new(|cx, args| {
-                                    template: *template,
+                                STATE_OBJECT.with_borrow_mut(|s| {
-                                    accept_fn: Box::new(|cx, args| {
+                                    accept_fn(s, cx, args)
-                                        STATE_OBJECT.with_borrow_mut(|s| {
+                                })
-                                            accept_fn(s, cx, args)
+                            }),
-                                        })
+                            allowed_targets: <$names as crate::attributes::AttributeParser<$stage>>::ALLOWED_TARGETS,
-                                    }),
+                        });
-                                    allowed_targets: <$names as crate::attributes::AttributeParser<$stage>>::ALLOWED_TARGETS,
-                                    finalizer: Box::new(|cx| {
-                                        let state = STATE_OBJECT.take();
-                                        state.finalize(cx)
-                                    })
-                                });
-                            }
-                            Entry::Occupied(_) => panic!("Attribute {path:?} has multiple accepters"),
-                        }
                     }
+
+                    finalizes.push(Box::new(|cx| {
+                        let state = STATE_OBJECT.take();
+                        state.finalize(cx)
+                    }));
                 }
             )*
 
-            GroupTypeInner { accepters }
+            GroupTypeInner { accepters:accepts, finalizers:finalizes }
         });
     };
 }
@@ -144,10 +161,8 @@ attribute_parsers!(
         BodyStabilityParser,
         ConfusablesParser,
         ConstStabilityParser,
-        DocParser,
         MacroUseParser,
         NakedParser,
-        RustcCguTestAttributeParser,
         StabilityParser,
         UsedParser,
         // tidy-alphabetical-end
@@ -155,73 +170,46 @@ attribute_parsers!(
         // tidy-alphabetical-start
         Combine<AllowConstFnUnstableParser>,
         Combine<AllowInternalUnstableParser>,
-        Combine<CrateTypeParser>,
         Combine<DebuggerViualizerParser>,
         Combine<ForceTargetFeatureParser>,
         Combine<LinkParser>,
         Combine<ReprParser>,
-        Combine<RustcCleanParser>,
-        Combine<RustcLayoutParser>,
-        Combine<RustcMirParser>,
-        Combine<RustcThenThisWouldNeedParser>,
         Combine<TargetFeatureParser>,
         Combine<UnstableFeatureBoundParser>,
         // tidy-alphabetical-end
 
         // tidy-alphabetical-start
-        Single<CfiEncodingParser>,
-        Single<CollapseDebugInfoParser>,
         Single<CoverageParser>,
         Single<CrateNameParser>,
         Single<CustomMirParser>,
         Single<DeprecationParser>,
-        Single<DoNotRecommendParser>,
         Single<DummyParser>,
         Single<ExportNameParser>,
         Single<IgnoreParser>,
         Single<InlineParser>,
-        Single<InstructionSetParser>,
-        Single<LangParser>,
         Single<LinkNameParser>,
         Single<LinkOrdinalParser>,
         Single<LinkSectionParser>,
         Single<LinkageParser>,
         Single<MacroExportParser>,
         Single<MoveSizeLimitParser>,
-        Single<MustNotSuspendParser>,
         Single<MustUseParser>,
         Single<ObjcClassParser>,
         Single<ObjcSelectorParser>,
         Single<OptimizeParser>,
-        Single<PatchableFunctionEntryParser>,
         Single<PathAttributeParser>,
         Single<PatternComplexityLimitParser>,
         Single<ProcMacroDeriveParser>,
         Single<RecursionLimitParser>,
-        Single<ReexportTestHarnessMainParser>,
-        Single<RustcAbiParser>,
-        Single<RustcAllocatorZeroedVariantParser>,
         Single<RustcBuiltinMacroParser>,
-        Single<RustcDefPath>,
-        Single<RustcDeprecatedSafe2024Parser>,
-        Single<RustcDiagnosticItemParser>,
         Single<RustcForceInlineParser>,
-        Single<RustcIfThisChangedParser>,
         Single<RustcLayoutScalarValidRangeEndParser>,
         Single<RustcLayoutScalarValidRangeStartParser>,
-        Single<RustcLegacyConstGenericsParser>,
+        Single<RustcObjectLifetimeDefaultParser>,
-        Single<RustcLintOptDenyFieldAccessParser>,
-        Single<RustcMustImplementOneOfParser>,
-        Single<RustcNeverTypeOptionsParser>,
-        Single<RustcReservationImplParser>,
-        Single<RustcScalableVectorParser>,
         Single<RustcSimdMonomorphizeLaneLimitParser>,
-        Single<RustcSymbolName>,
-        Single<RustcTestMarkerParser>,
         Single<SanitizeParser>,
         Single<ShouldPanicParser>,
         Single<SkipDuringMethodDispatchParser>,
-        Single<TestRunnerParser>,
         Single<TransparencyParser>,
         Single<TypeLengthLimitParser>,
         Single<WindowsSubsystemParser>,
@@ -231,14 +219,11 @@ attribute_parsers!(
         Single<WithoutArgs<AutomaticallyDerivedParser>>,
         Single<WithoutArgs<CoinductiveParser>>,
         Single<WithoutArgs<ColdParser>>,
-        Single<WithoutArgs<CompilerBuiltinsParser>>,
         Single<WithoutArgs<ConstContinueParser>>,
         Single<WithoutArgs<ConstStabilityIndirectParser>>,
         Single<WithoutArgs<CoroutineParser>>,
-        Single<WithoutArgs<DefaultLibAllocatorParser>>,
         Single<WithoutArgs<DenyExplicitImplParser>>,
-        Single<WithoutArgs<DynIncompatibleTraitParser>>,
+        Single<WithoutArgs<DoNotImplementViaObjectParser>>,
-        Single<WithoutArgs<EiiForeignItemParser>>,
         Single<WithoutArgs<ExportStableParser>>,
         Single<WithoutArgs<FfiConstParser>>,
         Single<WithoutArgs<FfiPureParser>>,
@@ -247,75 +232,26 @@ attribute_parsers!(
         Single<WithoutArgs<MacroEscapeParser>>,
         Single<WithoutArgs<MarkerParser>>,
         Single<WithoutArgs<MayDangleParser>>,
-        Single<WithoutArgs<NeedsAllocatorParser>>,
-        Single<WithoutArgs<NeedsPanicRuntimeParser>>,
-        Single<WithoutArgs<NoBuiltinsParser>>,
         Single<WithoutArgs<NoCoreParser>>,
         Single<WithoutArgs<NoImplicitPreludeParser>>,
-        Single<WithoutArgs<NoLinkParser>>,
-        Single<WithoutArgs<NoMainParser>>,
         Single<WithoutArgs<NoMangleParser>>,
         Single<WithoutArgs<NoStdParser>>,
         Single<WithoutArgs<NonExhaustiveParser>>,
-        Single<WithoutArgs<PanicHandlerParser>>,
-        Single<WithoutArgs<PanicRuntimeParser>>,
         Single<WithoutArgs<ParenSugarParser>>,
         Single<WithoutArgs<PassByValueParser>>,
         Single<WithoutArgs<PinV2Parser>>,
         Single<WithoutArgs<PointeeParser>>,
-        Single<WithoutArgs<PreludeImportParser>>,
         Single<WithoutArgs<ProcMacroAttributeParser>>,
         Single<WithoutArgs<ProcMacroParser>>,
-        Single<WithoutArgs<ProfilerRuntimeParser>>,
         Single<WithoutArgs<PubTransparentParser>>,
-        Single<WithoutArgs<RustcAllocatorParser>>,
-        Single<WithoutArgs<RustcAllocatorZeroedParser>>,
-        Single<WithoutArgs<RustcCaptureAnalysisParser>>,
         Single<WithoutArgs<RustcCoherenceIsCoreParser>>,
-        Single<WithoutArgs<RustcConversionSuggestionParser>>,
-        Single<WithoutArgs<RustcDeallocatorParser>>,
-        Single<WithoutArgs<RustcDelayedBugFromInsideQueryParser>>,
-        Single<WithoutArgs<RustcDoNotConstCheckParser>>,
-        Single<WithoutArgs<RustcDumpDefParentsParser>>,
-        Single<WithoutArgs<RustcDumpItemBoundsParser>>,
-        Single<WithoutArgs<RustcDumpPredicatesParser>>,
-        Single<WithoutArgs<RustcDumpUserArgsParser>>,
-        Single<WithoutArgs<RustcDumpVtableParser>>,
-        Single<WithoutArgs<RustcEffectiveVisibilityParser>>,
-        Single<WithoutArgs<RustcEvaluateWhereClausesParser>>,
-        Single<WithoutArgs<RustcHasIncoherentInherentImplsParser>>,
-        Single<WithoutArgs<RustcHiddenTypeOfOpaquesParser>>,
-        Single<WithoutArgs<RustcInsignificantDtorParser>>,
-        Single<WithoutArgs<RustcIntrinsicConstStableIndirectParser>>,
-        Single<WithoutArgs<RustcIntrinsicParser>>,
-        Single<WithoutArgs<RustcLintOptTyParser>>,
-        Single<WithoutArgs<RustcLintQueryInstabilityParser>>,
-        Single<WithoutArgs<RustcLintUntrackedQueryInformationParser>>,
         Single<WithoutArgs<RustcMainParser>>,
-        Single<WithoutArgs<RustcNeverReturnsNullPointerParser>>,
-        Single<WithoutArgs<RustcNoImplicitAutorefsParser>>,
-        Single<WithoutArgs<RustcNoImplicitBoundsParser>>,
-        Single<WithoutArgs<RustcNoMirInlineParser>>,
-        Single<WithoutArgs<RustcNonConstTraitMethodParser>>,
-        Single<WithoutArgs<RustcNonnullOptimizationGuaranteedParser>>,
-        Single<WithoutArgs<RustcNounwindParser>>,
-        Single<WithoutArgs<RustcObjectLifetimeDefaultParser>>,
-        Single<WithoutArgs<RustcOffloadKernelParser>>,
-        Single<WithoutArgs<RustcOutlivesParser>>,
         Single<WithoutArgs<RustcPassIndirectlyInNonRusticAbisParser>>,
-        Single<WithoutArgs<RustcPreserveUbChecksParser>>,
-        Single<WithoutArgs<RustcProcMacroDeclsParser>>,
-        Single<WithoutArgs<RustcReallocatorParser>>,
-        Single<WithoutArgs<RustcRegionsParser>>,
         Single<WithoutArgs<RustcShouldNotBeCalledOnConstItems>>,
-        Single<WithoutArgs<RustcStrictCoherenceParser>>,
-        Single<WithoutArgs<RustcTrivialFieldReadsParser>>,
-        Single<WithoutArgs<RustcVarianceOfOpaquesParser>>,
-        Single<WithoutArgs<RustcVarianceParser>>,
         Single<WithoutArgs<SpecializationTraitParser>>,
         Single<WithoutArgs<StdInternalSymbolParser>>,
-        Single<WithoutArgs<ThreadLocalParser>>,
         Single<WithoutArgs<TrackCallerParser>>,
+        Single<WithoutArgs<TypeConstParser>>,
         Single<WithoutArgs<UnsafeSpecializationMarkerParser>>,
         // tidy-alphabetical-end
     ];
@@ -341,6 +277,8 @@ pub trait Stage: Sized + 'static + Sealed {
     ) -> ErrorGuaranteed;
 
     fn should_emit(&self) -> ShouldEmit;
+
+    fn id_is_crate_root(id: Self::Id) -> bool;
 }
 
 // allow because it's a sealed trait
@@ -362,6 +300,10 @@ impl Stage for Early {
     fn should_emit(&self) -> ShouldEmit {
         self.emit_errors
     }
+
+    fn id_is_crate_root(id: Self::Id) -> bool {
+        id == CRATE_NODE_ID
+    }
 }
 
 // allow because it's a sealed trait
@@ -381,7 +323,11 @@ impl Stage for Late {
     }
 
     fn should_emit(&self) -> ShouldEmit {
-        ShouldEmit::ErrorsAndLints { recovery: Recovery::Allowed }
+        ShouldEmit::ErrorsAndLints
+    }
+
+    fn id_is_crate_root(id: Self::Id) -> bool {
+        id == CRATE_HIR_ID
     }
 }
 
@@ -435,19 +381,19 @@ impl<'f, 'sess: 'f, S: Stage> SharedContext<'f, 'sess, S> {
     /// Emit a lint. This method is somewhat special, since lints emitted during attribute parsing
     /// must be delayed until after HIR is built. This method will take care of the details of
     /// that.
-    pub(crate) fn emit_lint(&mut self, lint: &'static Lint, kind: AttributeLintKind, span: Span) {
+    pub(crate) fn emit_lint(&mut self, lint: AttributeLintKind, span: Span) {
         if !matches!(
             self.stage.should_emit(),
-            ShouldEmit::ErrorsAndLints { .. } | ShouldEmit::EarlyFatal { also_emit_lints: true }
+            ShouldEmit::ErrorsAndLints | ShouldEmit::EarlyFatal { also_emit_lints: true }
         ) {
             return;
         }
-        (self.emit_lint)(LintId::of(lint), span, kind);
+        let id = self.target_id;
+        (self.emit_lint)(AttributeLint { id, span, kind: lint });
     }
 
     pub(crate) fn warn_unused_duplicate(&mut self, used_span: Span, unused_span: Span) {
         self.emit_lint(
-            rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
             AttributeLintKind::UnusedDuplicate {
                 this: unused_span,
                 other: used_span,
@@ -463,7 +409,6 @@ impl<'f, 'sess: 'f, S: Stage> SharedContext<'f, 'sess, S> {
         unused_span: Span,
     ) {
         self.emit_lint(
-            rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
             AttributeLintKind::UnusedDuplicate {
                 this: unused_span,
                 other: used_span,
@@ -475,20 +420,13 @@ impl<'f, 'sess: 'f, S: Stage> SharedContext<'f, 'sess, S> {
 }
 
 impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
-    fn emit_parse_error(
+    pub(crate) fn unknown_key(
         &self,
         span: Span,
-        reason: AttributeParseErrorReason<'_>,
+        found: String,
+        options: &'static [&'static str],
     ) -> ErrorGuaranteed {
-        self.emit_err(AttributeParseError {
+        self.emit_err(UnknownMetaItem { span, item: found, expected: options })
-            span,
-            attr_span: self.attr_span,
-            template: self.template.clone(),
-            path: self.attr_path.clone(),
-            description: self.parsed_description,
-            reason,
-            suggestions: self.suggestions(),
-        })
     }
 
     /// error that a string literal was expected.
@@ -500,101 +438,133 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         span: Span,
         actual_literal: Option<&MetaItemLit>,
     ) -> ErrorGuaranteed {
-        self.emit_parse_error(
+        self.emit_err(AttributeParseError {
             span,
-            AttributeParseErrorReason::ExpectedStringLiteral {
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedStringLiteral {
                 byte_string: actual_literal.and_then(|i| {
                     i.kind.is_bytestr().then(|| self.sess().source_map().start_point(i.span))
                 }),
             },
-        )
+            suggestions: self.suggestions(),
-    }
+        })
-
-    /// Error that a filename string literal was expected.
-    pub(crate) fn expected_filename_literal(&self, span: Span) {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedFilenameLiteral);
     }
 
     pub(crate) fn expected_integer_literal(&self, span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedIntegerLiteral)
+        self.emit_err(AttributeParseError {
-    }
-
-    pub(crate) fn expected_integer_literal_in_range(
-        &self,
-        span: Span,
-        lower_bound: isize,
-        upper_bound: isize,
-    ) -> ErrorGuaranteed {
-        self.emit_parse_error(
             span,
-            AttributeParseErrorReason::ExpectedIntegerLiteralInRange { lower_bound, upper_bound },
+            attr_span: self.attr_span,
-        )
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedIntegerLiteral,
+            suggestions: self.suggestions(),
+        })
     }
 
-    pub(crate) fn expected_list(&self, span: Span, args: &ArgParser) -> ErrorGuaranteed {
+    pub(crate) fn expected_list(&self, span: Span) -> ErrorGuaranteed {
-        let span = match args {
+        self.emit_err(AttributeParseError {
-            ArgParser::NoArgs => span,
-            ArgParser::List(list) => list.span,
-            ArgParser::NameValue(nv) => nv.args_span(),
-        };
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedList)
-    }
-
-    pub(crate) fn expected_list_with_num_args_or_more(
-        &self,
-        args: usize,
-        span: Span,
-    ) -> ErrorGuaranteed {
-        self.emit_parse_error(
             span,
-            AttributeParseErrorReason::ExpectedListWithNumArgsOrMore { args },
+            attr_span: self.attr_span,
-        )
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedList,
+            suggestions: self.suggestions(),
+        })
     }
 
-    pub(crate) fn expected_list_or_no_args(&self, span: Span) -> ErrorGuaranteed {
+    pub(crate) fn expected_no_args(&self, args_span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedListOrNoArgs)
+        self.emit_err(AttributeParseError {
-    }
+            span: args_span,
-
+            attr_span: self.attr_span,
-    pub(crate) fn expected_nv_or_no_args(&self, span: Span) -> ErrorGuaranteed {
+            template: self.template.clone(),
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedNameValueOrNoArgs)
+            path: self.attr_path.clone(),
-    }
+            description: self.parsed_description,
-
+            reason: AttributeParseErrorReason::ExpectedNoArgs,
-    pub(crate) fn expected_non_empty_string_literal(&self, span: Span) -> ErrorGuaranteed {
+            suggestions: self.suggestions(),
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedNonEmptyStringLiteral)
+        })
-    }
-
-    pub(crate) fn expected_no_args(&self, span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedNoArgs)
     }
 
     /// emit an error that a `name` was expected here
     pub(crate) fn expected_identifier(&self, span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedIdentifier)
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedIdentifier,
+            suggestions: self.suggestions(),
+        })
     }
 
     /// emit an error that a `name = value` pair was expected at this span. The symbol can be given for
     /// a nicer error message talking about the specific name that was found lacking a value.
     pub(crate) fn expected_name_value(&self, span: Span, name: Option<Symbol>) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedNameValue(name))
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedNameValue(name),
+            suggestions: self.suggestions(),
+        })
     }
 
     /// emit an error that a `name = value` pair was found where that name was already seen.
     pub(crate) fn duplicate_key(&self, span: Span, key: Symbol) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::DuplicateKey(key))
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::DuplicateKey(key),
+            suggestions: self.suggestions(),
+        })
     }
 
     /// an error that should be emitted when a [`MetaItemOrLitParser`](crate::parser::MetaItemOrLitParser)
     /// was expected *not* to be a literal, but instead a meta item.
     pub(crate) fn unexpected_literal(&self, span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::UnexpectedLiteral)
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::UnexpectedLiteral,
+            suggestions: self.suggestions(),
+        })
     }
 
     pub(crate) fn expected_single_argument(&self, span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedSingleArgument)
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedSingleArgument,
+            suggestions: self.suggestions(),
+        })
     }
 
     pub(crate) fn expected_at_least_one_argument(&self, span: Span) -> ErrorGuaranteed {
-        self.emit_parse_error(span, AttributeParseErrorReason::ExpectedAtLeastOneArgument)
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedAtLeastOneArgument,
+            suggestions: self.suggestions(),
+        })
     }
 
     /// produces an error along the lines of `expected one of [foo, meow]`
@@ -603,14 +573,19 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         span: Span,
         possibilities: &[Symbol],
     ) -> ErrorGuaranteed {
-        self.emit_parse_error(
+        self.emit_err(AttributeParseError {
             span,
-            AttributeParseErrorReason::ExpectedSpecificArgument {
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedSpecificArgument {
                 possibilities,
                 strings: false,
                 list: false,
             },
-        )
+            suggestions: self.suggestions(),
+        })
     }
 
     /// produces an error along the lines of `expected one of [foo, meow] as an argument`.
@@ -620,14 +595,19 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         span: Span,
         possibilities: &[Symbol],
     ) -> ErrorGuaranteed {
-        self.emit_parse_error(
+        self.emit_err(AttributeParseError {
             span,
-            AttributeParseErrorReason::ExpectedSpecificArgument {
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedSpecificArgument {
                 possibilities,
                 strings: false,
                 list: true,
             },
-        )
+            suggestions: self.suggestions(),
+        })
     }
 
     /// produces an error along the lines of `expected one of ["foo", "meow"]`
@@ -636,36 +616,30 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         span: Span,
         possibilities: &[Symbol],
     ) -> ErrorGuaranteed {
-        self.emit_parse_error(
+        self.emit_err(AttributeParseError {
             span,
-            AttributeParseErrorReason::ExpectedSpecificArgument {
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            path: self.attr_path.clone(),
+            description: self.parsed_description,
+            reason: AttributeParseErrorReason::ExpectedSpecificArgument {
                 possibilities,
                 strings: true,
                 list: false,
             },
-        )
+            suggestions: self.suggestions(),
+        })
     }
 
     pub(crate) fn warn_empty_attribute(&mut self, span: Span) {
-        let attr_path = self.attr_path.clone().to_string();
+        let attr_path = self.attr_path.clone();
         let valid_without_list = self.template.word;
         self.emit_lint(
-            rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
             AttributeLintKind::EmptyAttribute { first_span: span, attr_path, valid_without_list },
             span,
         );
     }
 
-    pub(crate) fn warn_ill_formed_attribute_input(&mut self, lint: &'static Lint) {
-        let suggestions = self.suggestions();
-        let span = self.attr_span;
-        self.emit_lint(
-            lint,
-            AttributeLintKind::IllFormedAttributeInput { suggestions, docs: None },
-            span,
-        );
-    }
-
     pub(crate) fn suggestions(&self) -> Vec<String> {
         let style = match self.parsed_description {
             // If the outer and inner spans are equal, we are parsing an embedded attribute
@@ -704,11 +678,10 @@ pub struct SharedContext<'p, 'sess, S: Stage> {
     pub(crate) cx: &'p mut AttributeParser<'sess, S>,
     /// The span of the syntactical component this attribute was applied to
     pub(crate) target_span: Span,
-    pub(crate) target: rustc_hir::Target,
+    /// The id ([`NodeId`] if `S` is `Early`, [`HirId`] if `S` is `Late`) of the syntactical component this attribute was applied to
+    pub(crate) target_id: S::Id,
 
-    /// The second argument of the closure is a [`NodeId`] if `S` is `Early` and a [`HirId`] if `S`
+    pub(crate) emit_lint: &'p mut dyn FnMut(AttributeLint<S::Id>),
-    /// is `Late` and is the ID of the syntactical component this attribute was applied to.
-    pub(crate) emit_lint: &'p mut dyn FnMut(LintId, Span, AttributeLintKind),
 }
 
 /// Context given to every attribute parser during finalization.
@@ -724,7 +697,7 @@ pub(crate) struct FinalizeContext<'p, 'sess, S: Stage> {
     ///
     /// Usually, you should use normal attribute parsing logic instead,
     /// especially when making a *denylist* of other attributes.
-    pub(crate) all_attrs: &'p [RefPathParser<'p>],
+    pub(crate) all_attrs: &'p [PathParser<'p>],
 }
 
 impl<'p, 'sess: 'p, S: Stage> Deref for FinalizeContext<'p, 'sess, S> {
@@ -770,18 +743,9 @@ pub enum ShouldEmit {
     EarlyFatal { also_emit_lints: bool },
     /// The operation will emit errors and lints.
     /// This is usually what you need.
-    ErrorsAndLints {
+    ErrorsAndLints,
-        /// Whether [`ArgParser`] will attempt to recover from errors.
+    /// The operation will emit *not* errors and lints.
-        ///
+    /// Use this if you are *sure* that this operation will be called at a different time with `ShouldEmit::ErrorsAndLints`.
-        /// Whether it is allowed to recover from bad input (like an invalid literal). Setting
-        /// this to `Forbidden` will instead return early, and not raise errors except at the top
-        /// level (in [`ArgParser::from_attr_args`]).
-        recovery: Recovery,
-    },
-    /// The operation will *not* emit errors and lints.
-    ///
-    /// The parser can still call `delay_bug`, so you *must* ensure that this operation will also be
-    /// called with `ShouldEmit::ErrorsAndLints`.
     Nothing,
 }
 
@@ -790,7 +754,7 @@ impl ShouldEmit {
         match self {
             ShouldEmit::EarlyFatal { .. } if diag.level() == Level::DelayedBug => diag.emit(),
             ShouldEmit::EarlyFatal { .. } => diag.upgrade_to_fatal().emit(),
-            ShouldEmit::ErrorsAndLints { .. } => diag.emit(),
+            ShouldEmit::ErrorsAndLints => diag.emit(),
             ShouldEmit::Nothing => diag.delay_as_bug(),
         }
     }

compiler/rustc_attr_parsing/src/early_parsed.rs

@@ -1,53 +0,0 @@
-use rustc_ast::EarlyParsedAttribute;
-use rustc_ast::attr::data_structures::CfgEntry;
-use rustc_hir::Attribute;
-use rustc_hir::attrs::AttributeKind;
-use rustc_span::{Span, Symbol, sym};
-use thin_vec::ThinVec;
-
-pub(crate) const EARLY_PARSED_ATTRIBUTES: &[&[Symbol]] =
-    &[&[sym::cfg_trace], &[sym::cfg_attr_trace]];
-
-/// This struct contains the state necessary to convert early parsed attributes to hir attributes
-/// The only conversion that really happens here is that multiple early parsed attributes are
-/// merged into a single hir attribute, representing their combined state.
-/// FIXME: We should make this a nice and extendable system if this is going to be used more often
-#[derive(Default)]
-pub(crate) struct EarlyParsedState {
-    /// Attribute state for `#[cfg]` trace attributes
-    cfg_trace: ThinVec<(CfgEntry, Span)>,
-
-    /// Attribute state for `#[cfg_attr]` trace attributes
-    /// The arguments of these attributes is no longer relevant for any later passes, only their presence.
-    /// So we discard the arguments here.
-    cfg_attr_trace: bool,
-}
-
-impl EarlyParsedState {
-    pub(crate) fn accept_early_parsed_attribute(
-        &mut self,
-        attr_span: Span,
-        lower_span: impl Copy + Fn(Span) -> Span,
-        parsed: &EarlyParsedAttribute,
-    ) {
-        match parsed {
-            EarlyParsedAttribute::CfgTrace(cfg) => {
-                let mut cfg = cfg.clone();
-                cfg.lower_spans(lower_span);
-                self.cfg_trace.push((cfg, attr_span));
-            }
-            EarlyParsedAttribute::CfgAttrTrace => {
-                self.cfg_attr_trace = true;
-            }
-        }
-    }
-
-    pub(crate) fn finalize_early_parsed_attributes(self, attributes: &mut Vec<Attribute>) {
-        if !self.cfg_trace.is_empty() {
-            attributes.push(Attribute::Parsed(AttributeKind::CfgTrace(self.cfg_trace)));
-        }
-        if self.cfg_attr_trace {
-            attributes.push(Attribute::Parsed(AttributeKind::CfgAttrTrace));
-        }
-    }
-}

compiler/rustc_attr_parsing/src/interface.rs

@@ -1,20 +1,17 @@
-use std::convert::identity;
+use std::borrow::Cow;
 
 use rustc_ast as ast;
-use rustc_ast::token::DocFragmentKind;
+use rustc_ast::{AttrStyle, NodeId, Safety};
-use rustc_ast::{AttrItemKind, AttrStyle, NodeId, Safety};
 use rustc_errors::DiagCtxtHandle;
 use rustc_feature::{AttributeTemplate, Features};
 use rustc_hir::attrs::AttributeKind;
-use rustc_hir::lints::AttributeLintKind;
+use rustc_hir::lints::AttributeLint;
 use rustc_hir::{AttrArgs, AttrItem, AttrPath, Attribute, HashIgnoredAttrId, Target};
 use rustc_session::Session;
-use rustc_session::lint::{BuiltinLintDiag, LintId};
 use rustc_span::{DUMMY_SP, Span, Symbol, sym};
 
-use crate::context::{AcceptContext, FinalizeContext, FinalizeFn, SharedContext, Stage};
+use crate::context::{AcceptContext, FinalizeContext, SharedContext, Stage};
-use crate::early_parsed::{EARLY_PARSED_ATTRIBUTES, EarlyParsedState};
+use crate::parser::{ArgParser, MetaItemParser, PathParser};
-use crate::parser::{ArgParser, PathParser, RefPathParser};
 use crate::session_diagnostics::ParsedDescription;
 use crate::{Early, Late, OmitDoc, ShouldEmit};
 
@@ -113,16 +110,12 @@ impl<'sess> AttributeParser<'sess, Early> {
         p.parse_attribute_list(
             attrs,
             target_span,
+            target_node_id,
             target,
             OmitDoc::Skip,
             std::convert::identity,
-            |lint_id, span, kind| {
+            |lint| {
-                sess.psess.buffer_lint(
+                crate::lints::emit_attribute_lint(&lint, sess);
-                    lint_id.lint,
-                    span,
-                    target_node_id,
-                    BuiltinLintDiag::AttributeLint(kind),
-                )
             },
         )
     }
@@ -134,10 +127,9 @@ impl<'sess> AttributeParser<'sess, Early> {
         attr: &ast::Attribute,
         target_span: Span,
         target_node_id: NodeId,
-        target: Target,
         features: Option<&'sess Features>,
         emit_errors: ShouldEmit,
-        parse_fn: fn(cx: &mut AcceptContext<'_, '_, Early>, item: &ArgParser) -> Option<T>,
+        parse_fn: fn(cx: &mut AcceptContext<'_, '_, Early>, item: &ArgParser<'_>) -> Option<T>,
         template: &AttributeTemplate,
     ) -> Option<T> {
         let ast::AttrKind::Normal(normal_attr) = &attr.kind else {
@@ -145,28 +137,22 @@ impl<'sess> AttributeParser<'sess, Early> {
         };
         let parts =
             normal_attr.item.path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>();
-
+        let meta_parser = MetaItemParser::from_attr(normal_attr, &parts, &sess.psess, emit_errors)?;
-        let path = AttrPath::from_ast(&normal_attr.item.path, identity);
+        let path = meta_parser.path();
-        let args = ArgParser::from_attr_args(
+        let args = meta_parser.args();
-            &normal_attr.item.args.unparsed_ref().unwrap(),
-            &parts,
-            &sess.psess,
-            emit_errors,
-        )?;
         Self::parse_single_args(
             sess,
             attr.span,
             normal_attr.item.span(),
             attr.style,
-            path,
+            path.get_attribute_path(),
             Some(normal_attr.item.unsafety),
             ParsedDescription::Attribute,
             target_span,
             target_node_id,
-            target,
             features,
             emit_errors,
-            &args,
+            args,
             parse_fn,
             template,
         )
@@ -184,7 +170,6 @@ impl<'sess> AttributeParser<'sess, Early> {
         parsed_description: ParsedDescription,
         target_span: Span,
         target_node_id: NodeId,
-        target: Target,
         features: Option<&'sess Features>,
         emit_errors: ShouldEmit,
         args: &I,
@@ -198,22 +183,23 @@ impl<'sess> AttributeParser<'sess, Early> {
             sess,
             stage: Early { emit_errors },
         };
-        let mut emit_lint = |lint_id: LintId, span: Span, kind: AttributeLintKind| {
+        let mut emit_lint = |lint| {
-            sess.psess.buffer_lint(
+            crate::lints::emit_attribute_lint(&lint, sess);
-                lint_id.lint,
-                span,
-                target_node_id,
-                BuiltinLintDiag::AttributeLint(kind),
-            )
         };
         if let Some(safety) = attr_safety {
-            parser.check_attribute_safety(&attr_path, inner_span, safety, &mut emit_lint)
+            parser.check_attribute_safety(
+                &attr_path,
+                inner_span,
+                safety,
+                &mut emit_lint,
+                target_node_id,
+            )
         }
         let mut cx: AcceptContext<'_, 'sess, Early> = AcceptContext {
             shared: SharedContext {
                 cx: &mut parser,
                 target_span,
-                target,
+                target_id: target_node_id,
                 emit_lint: &mut emit_lint,
             },
             attr_span,
@@ -261,16 +247,15 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
         &mut self,
         attrs: &[ast::Attribute],
         target_span: Span,
+        target_id: S::Id,
         target: Target,
         omit_doc: OmitDoc,
+
         lower_span: impl Copy + Fn(Span) -> Span,
-        mut emit_lint: impl FnMut(LintId, Span, AttributeLintKind),
+        mut emit_lint: impl FnMut(AttributeLint<S::Id>),
     ) -> Vec<Attribute> {
         let mut attributes = Vec::new();
-        let mut attr_paths: Vec<RefPathParser<'_>> = Vec::new();
+        let mut attr_paths = Vec::new();
-        let mut early_parsed_state = EarlyParsedState::default();
-
-        let mut finalizers: Vec<&FinalizeFn<S>> = Vec::with_capacity(attrs.len());
 
         for attr in attrs {
             // If we're only looking for a single attribute, skip all the ones we don't care about.
@@ -285,12 +270,10 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
             // that's expanded right? But no, sometimes, when parsing attributes on macros,
             // we already use the lowering logic and these are still there. So, when `omit_doc`
             // is set we *also* want to ignore these.
-            let is_doc_attribute = attr.has_name(sym::doc);
+            if omit_doc == OmitDoc::Skip && attr.has_name(sym::doc) {
-            if omit_doc == OmitDoc::Skip && is_doc_attribute {
                 continue;
             }
 
-            let attr_span = lower_span(attr.span);
             match &attr.kind {
                 ast::AttrKind::DocComment(comment_kind, symbol) => {
                     if omit_doc == OmitDoc::Skip {
@@ -299,95 +282,67 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
 
                     attributes.push(Attribute::Parsed(AttributeKind::DocComment {
                         style: attr.style,
-                        kind: DocFragmentKind::Sugared(*comment_kind),
+                        kind: *comment_kind,
-                        span: attr_span,
+                        span: lower_span(attr.span),
                         comment: *symbol,
                     }))
                 }
+                // // FIXME: make doc attributes go through a proper attribute parser
+                // ast::AttrKind::Normal(n) if n.has_name(sym::doc) => {
+                //     let p = GenericMetaItemParser::from_attr(&n, self.dcx());
+                //
+                //     attributes.push(Attribute::Parsed(AttributeKind::DocComment {
+                //         style: attr.style,
+                //         kind: CommentKind::Line,
+                //         span: attr.span,
+                //         comment: p.args().name_value(),
+                //     }))
+                // }
                 ast::AttrKind::Normal(n) => {
-                    attr_paths.push(PathParser(&n.item.path));
+                    attr_paths.push(PathParser(Cow::Borrowed(&n.item.path)));
                     let attr_path = AttrPath::from_ast(&n.item.path, lower_span);
 
-                    let args = match &n.item.args {
-                        AttrItemKind::Unparsed(args) => args,
-                        AttrItemKind::Parsed(parsed) => {
-                            early_parsed_state
-                                .accept_early_parsed_attribute(attr_span, lower_span, parsed);
-                            continue;
-                        }
-                    };
-
                     self.check_attribute_safety(
                         &attr_path,
                         lower_span(n.item.span()),
                         n.item.unsafety,
                         &mut emit_lint,
+                        target_id,
                     );
 
                     let parts =
                         n.item.path.segments.iter().map(|seg| seg.ident.name).collect::<Vec<_>>();
 
-                    if let Some(accept) = S::parsers().accepters.get(parts.as_slice()) {
+                    if let Some(accepts) = S::parsers().accepters.get(parts.as_slice()) {
-                        let Some(args) = ArgParser::from_attr_args(
+                        let Some(parser) = MetaItemParser::from_attr(
-                            args,
+                            n,
                             &parts,
                             &self.sess.psess,
                             self.stage.should_emit(),
                         ) else {
                             continue;
                         };
+                        let args = parser.args();
+                        for accept in accepts {
+                            let mut cx: AcceptContext<'_, 'sess, S> = AcceptContext {
+                                shared: SharedContext {
+                                    cx: self,
+                                    target_span,
+                                    target_id,
+                                    emit_lint: &mut emit_lint,
+                                },
+                                attr_span: lower_span(attr.span),
+                                inner_span: lower_span(n.item.span()),
+                                attr_style: attr.style,
+                                parsed_description: ParsedDescription::Attribute,
+                                template: &accept.template,
+                                attr_path: attr_path.clone(),
+                            };
 
-                        // Special-case handling for `#[doc = "..."]`: if we go through with
+                            (accept.accept_fn)(&mut cx, args);
-                        // `DocParser`, the order of doc comments will be messed up because `///`
+                            if !matches!(cx.stage.should_emit(), ShouldEmit::Nothing) {
-                        // doc comments are added into `attributes` whereas attributes parsed with
+                                Self::check_target(&accept.allowed_targets, target, &mut cx);
-                        // `DocParser` are added into `parsed_attributes` which are then appended
+                            }
-                        // to `attributes`. So if you have:
-                        //
-                        // /// bla
-                        // #[doc = "a"]
-                        // /// blob
-                        //
-                        // You would get:
-                        //
-                        // bla
-                        // blob
-                        // a
-                        if is_doc_attribute
-                            && let ArgParser::NameValue(nv) = &args
-                            // If not a string key/value, it should emit an error, but to make
-                            // things simpler, it's handled in `DocParser` because it's simpler to
-                            // emit an error with `AcceptContext`.
-                            && let Some(comment) = nv.value_as_str()
-                        {
-                            attributes.push(Attribute::Parsed(AttributeKind::DocComment {
-                                style: attr.style,
-                                kind: DocFragmentKind::Raw(nv.value_span),
-                                span: attr_span,
-                                comment,
-                            }));
-                            continue;
-                        }
-
-                        let mut cx: AcceptContext<'_, 'sess, S> = AcceptContext {
-                            shared: SharedContext {
-                                cx: self,
-                                target_span,
-                                target,
-                                emit_lint: &mut emit_lint,
-                            },
-                            attr_span,
-                            inner_span: lower_span(n.item.span()),
-                            attr_style: attr.style,
-                            parsed_description: ParsedDescription::Attribute,
-                            template: &accept.template,
-                            attr_path: attr_path.clone(),
-                        };
-
-                        (accept.accept_fn)(&mut cx, &args);
-                        finalizers.push(&accept.finalizer);
-
-                        if !matches!(cx.stage.should_emit(), ShouldEmit::Nothing) {
-                            Self::check_target(&accept.allowed_targets, target, &mut cx);
                         }
                     } else {
                         // If we're here, we must be compiling a tool attribute... Or someone
@@ -407,43 +362,39 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
 
                         attributes.push(Attribute::Unparsed(Box::new(AttrItem {
                             path: attr_path.clone(),
-                            args: self
+                            args: self.lower_attr_args(&n.item.args, lower_span),
-                                .lower_attr_args(n.item.args.unparsed_ref().unwrap(), lower_span),
                             id: HashIgnoredAttrId { attr_id: attr.id },
                             style: attr.style,
-                            span: attr_span,
+                            span: lower_span(attr.span),
                         })));
                     }
                 }
             }
         }
 
-        early_parsed_state.finalize_early_parsed_attributes(&mut attributes);
+        let mut parsed_attributes = Vec::new();
-        for f in &finalizers {
+        for f in &S::parsers().finalizers {
             if let Some(attr) = f(&mut FinalizeContext {
-                shared: SharedContext { cx: self, target_span, target, emit_lint: &mut emit_lint },
+                shared: SharedContext {
+                    cx: self,
+                    target_span,
+                    target_id,
+                    emit_lint: &mut emit_lint,
+                },
                 all_attrs: &attr_paths,
             }) {
-                attributes.push(Attribute::Parsed(attr));
+                parsed_attributes.push(Attribute::Parsed(attr));
             }
         }
 
+        attributes.extend(parsed_attributes);
+
         attributes
     }
 
     /// Returns whether there is a parser for an attribute with this name
     pub fn is_parsed_attribute(path: &[Symbol]) -> bool {
-        /// The list of attributes that are parsed attributes,
-        /// even though they don't have a parser in `Late::parsers()`
-        const SPECIAL_ATTRIBUTES: &[&[Symbol]] = &[
-            // Cfg attrs are removed after being early-parsed, so don't need to be in the parser list
-            &[sym::cfg],
-            &[sym::cfg_attr],
-        ];
-
         Late::parsers().accepters.contains_key(path)
-            || EARLY_PARSED_ATTRIBUTES.contains(&path)
-            || SPECIAL_ATTRIBUTES.contains(&path)
     }
 
     fn lower_attr_args(&self, args: &ast::AttrArgs, lower_span: impl Fn(Span) -> Span) -> AttrArgs {

compiler/rustc_attr_parsing/src/lib.rs

@@ -78,8 +78,6 @@
 
 // tidy-alphabetical-start
 #![feature(decl_macro)]
-#![feature(if_let_guard)]
-#![feature(iter_intersperse)]
 #![recursion_limit = "256"]
 // tidy-alphabetical-end
 
@@ -99,7 +97,7 @@ mod interface;
 /// like lists or name-value pairs.
 pub mod parser;
 
-mod early_parsed;
+mod lints;
 mod safety;
 mod session_diagnostics;
 mod target_checking;
@@ -108,8 +106,12 @@ pub mod validate_attr;
 pub use attributes::cfg::{
     CFG_TEMPLATE, EvalConfigResult, eval_config_entry, parse_cfg, parse_cfg_attr, parse_cfg_entry,
 };
+pub use attributes::cfg_old::*;
 pub use attributes::cfg_select::*;
-pub use attributes::util::{is_builtin_attr, parse_version};
+pub use attributes::util::{is_builtin_attr, is_doc_alias_attrs_contain_symbol, parse_version};
 pub use context::{Early, Late, OmitDoc, ShouldEmit};
 pub use interface::AttributeParser;
+pub use lints::emit_attribute_lint;
 pub use session_diagnostics::ParsedDescription;
+
+rustc_fluent_macro::fluent_messages! { "../messages.ftl" }

compiler/rustc_attr_parsing/src/lints.rs

@@ -0,0 +1,114 @@
+use std::borrow::Cow;
+
+use rustc_errors::{DiagArgValue, LintEmitter};
+use rustc_hir::Target;
+use rustc_hir::lints::{AttributeLint, AttributeLintKind};
+use rustc_span::sym;
+
+use crate::session_diagnostics;
+
+pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<L::Id>, lint_emitter: L) {
+    let AttributeLint { id, span, kind } = lint;
+
+    match kind {
+        &AttributeLintKind::UnusedDuplicate { this, other, warning } => lint_emitter
+            .emit_node_span_lint(
+                rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
+                *id,
+                *span,
+                session_diagnostics::UnusedDuplicate { this, other, warning },
+            ),
+        AttributeLintKind::IllFormedAttributeInput { suggestions } => {
+            lint_emitter.emit_node_span_lint(
+                rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT,
+                *id,
+                *span,
+                session_diagnostics::IllFormedAttributeInput {
+                    num_suggestions: suggestions.len(),
+                    suggestions: DiagArgValue::StrListSepByAnd(
+                        suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                    ),
+                },
+            );
+        }
+        AttributeLintKind::InvalidMacroExportArguments { suggestions } => lint_emitter
+            .emit_node_span_lint(
+                rustc_session::lint::builtin::INVALID_MACRO_EXPORT_ARGUMENTS,
+                *id,
+                *span,
+                session_diagnostics::IllFormedAttributeInput {
+                    num_suggestions: suggestions.len(),
+                    suggestions: DiagArgValue::StrListSepByAnd(
+                        suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                    ),
+                },
+            ),
+        AttributeLintKind::EmptyAttribute { first_span, attr_path, valid_without_list } => {
+            lint_emitter.emit_node_span_lint(
+                rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
+                *id,
+                *first_span,
+                session_diagnostics::EmptyAttributeList {
+                    attr_span: *first_span,
+                    attr_path: attr_path.clone(),
+                    valid_without_list: *valid_without_list,
+                },
+            )
+        }
+        AttributeLintKind::InvalidTarget { name, target, applied, only } => lint_emitter
+            .emit_node_span_lint(
+                // This check is here because `deprecated` had its own lint group and removing this would be a breaking change
+                if name.segments[0].name == sym::deprecated
+                    && ![
+                        Target::Closure,
+                        Target::Expression,
+                        Target::Statement,
+                        Target::Arm,
+                        Target::MacroCall,
+                    ]
+                    .contains(target)
+                {
+                    rustc_session::lint::builtin::USELESS_DEPRECATED
+                } else {
+                    rustc_session::lint::builtin::UNUSED_ATTRIBUTES
+                },
+                *id,
+                *span,
+                session_diagnostics::InvalidTargetLint {
+                    name: name.clone(),
+                    target: target.plural_name(),
+                    applied: DiagArgValue::StrListSepByAnd(
+                        applied.into_iter().map(|i| Cow::Owned(i.to_string())).collect(),
+                    ),
+                    only,
+                    attr_span: *span,
+                },
+            ),
+
+        &AttributeLintKind::InvalidStyle { ref name, is_used_as_inner, target, target_span } => {
+            lint_emitter.emit_node_span_lint(
+                rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
+                *id,
+                *span,
+                session_diagnostics::InvalidAttrStyle {
+                    name: name.clone(),
+                    is_used_as_inner,
+                    target_span: (!is_used_as_inner).then_some(target_span),
+                    target,
+                },
+            )
+        }
+        &AttributeLintKind::UnsafeAttrOutsideUnsafe {
+            attribute_name_span,
+            sugg_spans: (left, right),
+        } => lint_emitter.emit_node_span_lint(
+            rustc_session::lint::builtin::UNSAFE_ATTR_OUTSIDE_UNSAFE,
+            *id,
+            *span,
+            session_diagnostics::UnsafeAttrOutsideUnsafeLint {
+                span: attribute_name_span,
+                suggestion: session_diagnostics::UnsafeAttrOutsideUnsafeSuggestion { left, right },
+            },
+        ),
+    }
+}