Auto merge of #149572 - cuviper:beta-next, r=cuviper

[beta] backports

- rustdoc: Use configured target modifiers when collecting doctests rust-lang/rust#148068
- fix(rustdoc): Color doctest errors rust-lang/rust#148834
- Fix the issue of unused assignment from MIR liveness checking rust-lang/rust#149072
- Skip unused variables warning for unreachable code rust-lang/rust#149096
- In `BTreeMap::eq`, do not compare the elements if the sizes are different. rust-lang/rust#149125
- Handle cycles when checking impl candidates for `doc(hidden)` rust-lang/rust#149185
- Generalize branch references rust-lang/rust#148395
  - only the commit updating CI scripts
- Change default branch references rust-lang/rust#148564

r? cuviper

.github/workflows/post-merge.yml

@@ -6,7 +6,7 @@ name: Post merge analysis
 on:
   push:
     branches:
-      - master
+      - main
 
 jobs:
   analysis:

compiler/rustc_errors/src/emitter.rs

@@ -3465,14 +3465,9 @@ impl Drop for Buffy {
 
 pub fn stderr_destination(color: ColorConfig) -> Destination {
     let buffer_writer = std::io::stderr();
-    let choice = color.to_color_choice();
     // We need to resolve `ColorChoice::Auto` before `Box`ing since
     // `ColorChoice::Auto` on `dyn Write` will always resolve to `Never`
-    let choice = if matches!(choice, ColorChoice::Auto) {
-        AutoStream::choice(&buffer_writer)
-    } else {
-        choice
-    };
+    let choice = get_stderr_color_choice(color, &buffer_writer);
     // On Windows we'll be performing global synchronization on the entire
     // system for emitting rustc errors, so there's no need to buffer
     // anything.
@@ -3487,6 +3482,11 @@ pub fn stderr_destination(color: ColorConfig) -> Destination {
     }
 }
 
+pub fn get_stderr_color_choice(color: ColorConfig, stderr: &std::io::Stderr) -> ColorChoice {
+    let choice = color.to_color_choice();
+    if matches!(choice, ColorChoice::Auto) { AutoStream::choice(stderr) } else { choice }
+}
+
 /// On Windows, BRIGHT_BLUE is hard to read on black. Use cyan instead.
 ///
 /// See #36178.

compiler/rustc_mir_transform/src/liveness.rs

@@ -45,6 +45,9 @@ struct Access {
     /// When we encounter multiple statements at the same location, we only increase the liveness,
     /// in order to avoid false positives.
     live: bool,
+    /// Is this a direct access to the place itself, no projections, or to a field?
+    /// This helps distinguish `x = ...` from `x.field = ...`
+    is_direct: bool,
 }
 
 #[tracing::instrument(level = "debug", skip(tcx), ret)]
@@ -689,15 +692,17 @@ impl<'a, 'tcx> AssignmentResult<'a, 'tcx> {
             |place: Place<'tcx>, kind, source_info: SourceInfo, live: &DenseBitSet<PlaceIndex>| {
                 if let Some((index, extra_projections)) = checked_places.get(place.as_ref()) {
                     if !is_indirect(extra_projections) {
+                        let is_direct = extra_projections.is_empty();
                         match assignments[index].entry(source_info) {
                             IndexEntry::Vacant(v) => {
-                                let access = Access { kind, live: live.contains(index) };
+                                let access = Access { kind, live: live.contains(index), is_direct };
                                 v.insert(access);
                             }
                             IndexEntry::Occupied(mut o) => {
                                 // There were already a sighting. Mark this statement as live if it
                                 // was, to avoid false positives.
                                 o.get_mut().live |= live.contains(index);
+                                o.get_mut().is_direct &= is_direct;
                             }
                         }
                     }
@@ -781,7 +786,7 @@ impl<'a, 'tcx> AssignmentResult<'a, 'tcx> {
                     continue;
                 };
                 let source_info = body.local_decls[place.local].source_info;
-                let access = Access { kind, live: live.contains(index) };
+                let access = Access { kind, live: live.contains(index), is_direct: true };
                 assignments[index].insert(source_info, access);
             }
         }
@@ -875,6 +880,33 @@ impl<'a, 'tcx> AssignmentResult<'a, 'tcx> {
         dead_captures
     }
 
+    /// Check if a local is referenced in any reachable basic block.
+    /// Variables in unreachable code (e.g., after `todo!()`) should not trigger unused warnings.
+    fn is_local_in_reachable_code(&self, local: Local) -> bool {
+        struct LocalVisitor {
+            target_local: Local,
+            found: bool,
+        }
+
+        impl<'tcx> Visitor<'tcx> for LocalVisitor {
+            fn visit_local(&mut self, local: Local, _context: PlaceContext, _location: Location) {
+                if local == self.target_local {
+                    self.found = true;
+                }
+            }
+        }
+
+        let mut visitor = LocalVisitor { target_local: local, found: false };
+        for (bb, bb_data) in traversal::postorder(self.body) {
+            visitor.visit_basic_block_data(bb, bb_data);
+            if visitor.found {
+                return true;
+            }
+        }
+
+        false
+    }
+
     /// Report fully unused locals, and forget the corresponding assignments.
     fn report_fully_unused(&mut self) {
         let tcx = self.tcx;
@@ -928,6 +960,10 @@ impl<'a, 'tcx> AssignmentResult<'a, 'tcx> {
 
             let statements = &mut self.assignments[index];
             if statements.is_empty() {
+                if !self.is_local_in_reachable_code(local) {
+                    continue;
+                }
+
                 let sugg = if from_macro {
                     errors::UnusedVariableSugg::NoSugg { span: def_span, name }
                 } else {
@@ -977,8 +1013,10 @@ impl<'a, 'tcx> AssignmentResult<'a, 'tcx> {
                     self.checked_places,
                     self.body,
                 ) {
-                    statements.clear();
-                    continue;
+                    statements.retain(|_, access| access.is_direct);
+                    if statements.is_empty() {
+                        continue;
+                    }
                 }
 
                 let typo = maybe_suggest_typo();
@@ -1049,26 +1087,28 @@ impl<'a, 'tcx> AssignmentResult<'a, 'tcx> {
 
             let Some((name, decl_span)) = self.checked_places.names[index] else { continue };
 
-            // We have outstanding assignments and with non-trivial drop.
-            // This is probably a drop-guard, so we do not issue a warning there.
-            if maybe_drop_guard(
+            let is_maybe_drop_guard = maybe_drop_guard(
                 tcx,
                 self.typing_env,
                 index,
                 &self.ever_dropped,
                 self.checked_places,
                 self.body,
-            ) {
-                continue;
-            }
+            );
 
             // We probed MIR in reverse order for dataflow.
             // We revert the vector to give a consistent order to the user.
-            for (source_info, Access { live, kind }) in statements.into_iter().rev() {
+            for (source_info, Access { live, kind, is_direct }) in statements.into_iter().rev() {
                 if live {
                     continue;
                 }
 
+                // If this place was dropped and has non-trivial drop,
+                // skip reporting field assignments.
+                if !is_direct && is_maybe_drop_guard {
+                    continue;
+                }
+
                 // Report the dead assignment.
                 let Some(hir_id) = source_info.scope.lint_root(&self.body.source_scopes) else {
                     continue;

compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs

@@ -1,11 +1,12 @@
 use core::ops::ControlFlow;
 use std::borrow::Cow;
+use std::collections::hash_set;
 use std::path::PathBuf;
 
 use rustc_abi::ExternAbi;
 use rustc_ast::ast::LitKind;
 use rustc_ast::{LitIntType, TraitObjectSyntax};
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::UnordSet;
 use rustc_errors::codes::*;
 use rustc_errors::{
@@ -1927,11 +1928,17 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         if self.tcx.visibility(did).is_accessible_from(body_def_id, self.tcx) {
                             // don't suggest foreign `#[doc(hidden)]` types
                             if !did.is_local() {
-                                while let Some(parent) = parent_map.get(&did) {
+                                let mut previously_seen_dids: FxHashSet<DefId> = Default::default();
+                                previously_seen_dids.insert(did);
+                                while let Some(&parent) = parent_map.get(&did)
+                                    && let hash_set::Entry::Vacant(v) =
+                                        previously_seen_dids.entry(parent)
+                                {
                                     if self.tcx.is_doc_hidden(did) {
                                         return false;
                                     }
-                                    did = *parent;
+                                    v.insert();
+                                    did = parent;
                                 }
                             }
                             true

compiler/rustc_trait_selection/src/lib.rs

@@ -20,6 +20,7 @@
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(default_field_values)]
+#![feature(hash_set_entry)]
 #![feature(if_let_guard)]
 #![feature(iter_intersperse)]
 #![feature(iterator_try_reduce)]

library/alloc/src/collections/btree/map.rs

@@ -2414,7 +2414,7 @@ impl<K, V> Default for BTreeMap<K, V> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<K: PartialEq, V: PartialEq, A: Allocator + Clone> PartialEq for BTreeMap<K, V, A> {
     fn eq(&self, other: &BTreeMap<K, V, A>) -> bool {
-        self.iter().eq(other)
+        self.len() == other.len() && self.iter().zip(other).all(|(a, b)| a == b)
     }
 }
 

library/alloctests/tests/collections/eq_diff_len.rs

@@ -0,0 +1,96 @@
+//! Regression tests which fail if some collections' `PartialEq::eq` impls compare
+//! elements when the collections have different sizes.
+//! This behavior is not guaranteed either way, so regressing these tests is fine
+//! if it is done on purpose.
+use std::cmp::Ordering;
+use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, LinkedList};
+
+/// This intentionally has a panicking `PartialEq` impl, to test that various
+/// collections' `PartialEq` impls don't actually compare elements if their sizes
+/// are unequal.
+///
+/// This is not advisable in normal code.
+#[derive(Debug, Clone, Copy, Hash)]
+struct Evil;
+
+impl PartialEq for Evil {
+    fn eq(&self, _: &Self) -> bool {
+        panic!("Evil::eq is evil");
+    }
+}
+impl Eq for Evil {}
+
+impl PartialOrd for Evil {
+    fn partial_cmp(&self, _: &Self) -> Option<Ordering> {
+        Some(Ordering::Equal)
+    }
+}
+
+impl Ord for Evil {
+    fn cmp(&self, _: &Self) -> Ordering {
+        // Constructing a `BTreeSet`/`BTreeMap` uses `cmp` on the elements,
+        // but comparing it with with `==` uses `eq` on the elements,
+        // so Evil::cmp doesn't need to be evil.
+        Ordering::Equal
+    }
+}
+
+// check Evil works
+#[test]
+#[should_panic = "Evil::eq is evil"]
+fn evil_eq_works() {
+    let v1 = vec![Evil];
+    let v2 = vec![Evil];
+
+    _ = v1 == v2;
+}
+
+// check various containers don't compare if their sizes are different
+
+#[test]
+fn vec_evil_eq() {
+    let v1 = vec![Evil];
+    let v2 = vec![Evil; 2];
+
+    assert_eq!(false, v1 == v2);
+}
+
+#[test]
+fn hashset_evil_eq() {
+    let s1 = HashSet::from([(0, Evil)]);
+    let s2 = HashSet::from([(0, Evil), (1, Evil)]);
+
+    assert_eq!(false, s1 == s2);
+}
+
+#[test]
+fn hashmap_evil_eq() {
+    let m1 = HashMap::from([(0, Evil)]);
+    let m2 = HashMap::from([(0, Evil), (1, Evil)]);
+
+    assert_eq!(false, m1 == m2);
+}
+
+#[test]
+fn btreeset_evil_eq() {
+    let s1 = BTreeSet::from([(0, Evil)]);
+    let s2 = BTreeSet::from([(0, Evil), (1, Evil)]);
+
+    assert_eq!(false, s1 == s2);
+}
+
+#[test]
+fn btreemap_evil_eq() {
+    let m1 = BTreeMap::from([(0, Evil)]);
+    let m2 = BTreeMap::from([(0, Evil), (1, Evil)]);
+
+    assert_eq!(false, m1 == m2);
+}
+
+#[test]
+fn linkedlist_evil_eq() {
+    let m1 = LinkedList::from([Evil]);
+    let m2 = LinkedList::from([Evil; 2]);
+
+    assert_eq!(false, m1 == m2);
+}

library/alloctests/tests/collections/mod.rs

@@ -1 +1,2 @@
 mod binary_heap;
+mod eq_diff_len;

src/ci/citool/src/jobs.rs

@@ -123,7 +123,7 @@ pub fn load_job_db(db: &str) -> anyhow::Result<JobDatabase> {
 /// modulo certain carve-outs" in [`validate_job_database`].
 ///
 /// This invariant is important to make sure that it's not easily possible (without modifying
-/// `citool`) to have PRs with red PR-only CI jobs merged into `master`, causing all subsequent PR
+/// `citool`) to have PRs with red PR-only CI jobs merged into `main`, causing all subsequent PR
 /// CI runs to be red until the cause is fixed.
 fn register_pr_jobs_as_auto_jobs(db: &mut JobDatabase) -> anyhow::Result<()> {
     for pr_job in &db.pr_jobs {
@@ -273,7 +273,7 @@ pub enum RunType {
     /// Merge attempt workflow
     AutoJob,
     /// Fake job only used for sharing Github Actions cache.
-    MasterJob,
+    MainJob,
 }
 
 /// Maximum number of custom try jobs that can be requested in a single
@@ -323,7 +323,7 @@ fn calculate_jobs(
             (jobs, "try", &db.envs.try_env)
         }
         RunType::AutoJob => (db.auto_jobs.clone(), "auto", &db.envs.auto_env),
-        RunType::MasterJob => return Ok(vec![]),
+        RunType::MainJob => return Ok(vec![]),
     };
     let jobs = substitute_github_vars(jobs.clone())
         .context("Failed to substitute GitHub context variables in jobs")?;
@@ -376,7 +376,7 @@ pub fn calculate_job_matrix(
     eprintln!("Run type: {run_type:?}");
 
     let jobs = calculate_jobs(&run_type, &db, channel)?;
-    if jobs.is_empty() && !matches!(run_type, RunType::MasterJob) {
+    if jobs.is_empty() && !matches!(run_type, RunType::MainJob) {
         return Err(anyhow::anyhow!("Computed job list is empty"));
     }
 
@@ -384,7 +384,7 @@ pub fn calculate_job_matrix(
         RunType::PullRequest => "pr",
         RunType::TryJob { .. } => "try",
         RunType::AutoJob => "auto",
-        RunType::MasterJob => "master",
+        RunType::MainJob => "main",
     };
 
     eprintln!("Output");

src/ci/citool/src/main.rs

@@ -47,7 +47,7 @@ impl GitHubContext {
                 Some(RunType::TryJob { job_patterns: patterns })
             }
             ("push", "refs/heads/auto") => Some(RunType::AutoJob),
-            ("push", "refs/heads/master") => Some(RunType::MasterJob),
+            ("push", "refs/heads/main") => Some(RunType::MainJob),
             _ => None,
         }
     }

src/ci/citool/tests/jobs.rs

@@ -46,11 +46,11 @@ fn pr_jobs() {
 }
 
 #[test]
-fn master_jobs() {
-    let stdout = get_matrix("push", "commit", "refs/heads/master");
+fn main_jobs() {
+    let stdout = get_matrix("push", "commit", "refs/heads/main");
     insta::assert_snapshot!(stdout, @r#"
     jobs=[]
-    run_type=master
+    run_type=main
     "#);
 }
 

src/ci/scripts/checkout-submodules.sh

@@ -17,7 +17,7 @@ ci_dir=$(cd $(dirname $0) && pwd)/..
 # On the beta channel we'll be automatically calculating the prerelease version
 # via the git history, so unshallow our shallow clone from CI.
 if [ "$(releaseChannel)" = "beta" ]; then
-  git fetch origin --unshallow beta master
+  git fetch origin --unshallow beta main
 fi
 
 function fetch_github_commit_archive {

src/ci/scripts/verify-backported-commits.sh

@@ -1,5 +1,6 @@
 #!/bin/bash
-# Ensure commits in beta are in master & commits in stable are in beta + master.
+# Ensure commits in beta are in the default branch & commits in stable are in beta + the default
+# branch.
 set -euo pipefail
 IFS=$'\n\t'
 
@@ -19,11 +20,11 @@ verify_backported_commits_main() {
   fi
 
   if [[ $ci_base_branch == "beta" ]]; then
-    verify_cherries master "$BETA_LIMIT" \
+    verify_cherries HEAD "$BETA_LIMIT" \
       || exit 1
 
   elif [[ $ci_base_branch == "stable" ]]; then
-    (verify_cherries master "$STABLE_LIMIT" \
+    (verify_cherries HEAD "$STABLE_LIMIT" \
       & verify_cherries beta "$STABLE_LIMIT") \
       || exit 1
 
@@ -64,7 +65,7 @@ verify_cherries() {
       continue
     fi
 
-    if ! is_in_master "$backport_sha"; then
+    if ! is_in_default_branch "$backport_sha"; then
       bad_backports+=("$sha")
       continue
     fi
@@ -85,7 +86,7 @@ verify_cherries() {
         done
         echo
         echo "do not match any commits in \`$1\`. If this was intended, add the text"
-        echo '\`backport-of: <SHA of a commit already in master>\`'
+        echo '\`backport-of: <SHA of a commit already in the default branch>\`'
         echo 'somewhere in the message of each of these commits.'
         echo
         failure=1
@@ -101,7 +102,7 @@ verify_cherries() {
         done
         echo
         echo 'have commit messages marked \`backport-of: <SHA>\`, but the SHA is not in'
-        echo '\`master\`.'
+        echo 'the default branch.'
         echo
         failure=1
   fi
@@ -132,11 +133,11 @@ get_backport() {
     | sed -n '/^.*backport-of:\s\?\([a-f0-9]\+\|nothing\).*/{s//\1/p;q}'
 }
 
-# Check if a commit is in master.
+# Check if a commit is in the default branch.
 #
 # $1 = <sha>
-is_in_master() {
-  git merge-base --is-ancestor "$1" origin/master 2> /dev/null
+is_in_default_branch() {
+  git merge-base --is-ancestor "$1" origin/HEAD 2> /dev/null
 }
 
 verify_backported_commits_main

src/ci/scripts/verify-channel.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # We want to make sure all PRs are targeting the right branch when they're
 # opened, otherwise we risk (for example) to land a beta-specific change to the
-# master branch. This script ensures the branch of the PR matches the channel.
+# default branch. This script ensures the branch of the PR matches the channel.
 
 set -euo pipefail
 IFS=$'\n\t'
@@ -16,7 +16,7 @@ fi
 channel=$(cat "$(ciCheckoutPath)/src/ci/channel")
 case "${channel}" in
     nightly)
-        channel_branch="master"
+        channel_branch="main"
         ;;
     beta)
         channel_branch="beta"

src/librustdoc/doctest.rs

@@ -166,6 +166,7 @@ pub(crate) fn run(dcx: DiagCtxtHandle<'_>, input: Input, options: RustdocOptions
         remap_path_prefix: options.remap_path_prefix.clone(),
         unstable_opts: options.unstable_opts.clone(),
         error_format: options.error_format.clone(),
+        target_modifiers: options.target_modifiers.clone(),
         ..config::Options::default()
     };
 

src/librustdoc/doctest/make.rs

@@ -8,8 +8,8 @@ use std::sync::Arc;
 use rustc_ast::token::{Delimiter, TokenKind};
 use rustc_ast::tokenstream::TokenTree;
 use rustc_ast::{self as ast, AttrStyle, HasAttrs, StmtKind};
-use rustc_errors::emitter::stderr_destination;
-use rustc_errors::{AutoStream, ColorConfig, DiagCtxtHandle};
+use rustc_errors::emitter::get_stderr_color_choice;
+use rustc_errors::{AutoStream, ColorChoice, ColorConfig, DiagCtxtHandle};
 use rustc_parse::lexer::StripTokens;
 use rustc_parse::new_parser_from_source_str;
 use rustc_session::parse::ParseSess;
@@ -446,7 +446,7 @@ fn parse_source(
     span: Span,
 ) -> Result<ParseSourceInfo, ()> {
     use rustc_errors::DiagCtxt;
-    use rustc_errors::emitter::{Emitter, HumanEmitter};
+    use rustc_errors::emitter::HumanEmitter;
     use rustc_span::source_map::FilePathMapping;
 
     let mut info =
@@ -458,9 +458,12 @@ fn parse_source(
 
     let sm = Arc::new(SourceMap::new(FilePathMapping::empty()));
     let translator = rustc_driver::default_translator();
-    info.supports_color =
-        HumanEmitter::new(stderr_destination(ColorConfig::Auto), translator.clone())
-            .supports_color();
+    let supports_color = match get_stderr_color_choice(ColorConfig::Auto, &std::io::stderr()) {
+        ColorChoice::Auto => unreachable!(),
+        ColorChoice::AlwaysAnsi | ColorChoice::Always => true,
+        ColorChoice::Never => false,
+    };
+    info.supports_color = supports_color;
     // Any errors in parsing should also appear when the doctest is compiled for real, so just
     // send all the errors that the parser emits directly into a `Sink` instead of stderr.
     let emitter = HumanEmitter::new(AutoStream::never(Box::new(io::sink())), translator);

src/stage0

@@ -2,7 +2,7 @@ dist_server=https://static.rust-lang.org
 artifacts_server=https://ci-artifacts.rust-lang.org/rustc-builds
 artifacts_with_llvm_assertions_server=https://ci-artifacts.rust-lang.org/rustc-builds-alt
 git_merge_commit_email=bors@rust-lang.org
-nightly_branch=master
+nightly_branch=main
 
 # The configuration above this comment is editable, and can be changed
 # by forks of the repository if they have alternate values.

tests/run-make/rustdoc-target-modifiers/rmake.rs

@@ -25,4 +25,43 @@ fn main() {
         .target("aarch64-unknown-none-softfloat")
         .arg("-Zfixed-x18")
         .run();
+
+    rustdoc()
+        .input("c.rs")
+        .crate_type("rlib")
+        .extern_("d", "libd.rmeta")
+        .target("aarch64-unknown-none-softfloat")
+        .arg("-Zfixed-x18")
+        .arg("--test")
+        .run();
+
+    rustdoc()
+        .input("c.rs")
+        .edition("2024")
+        .crate_type("rlib")
+        .extern_("d", "libd.rmeta")
+        .target("aarch64-unknown-none-softfloat")
+        .arg("-Zfixed-x18")
+        .arg("--test")
+        .run();
+
+    // rustdoc --test detects ABI mismatch
+    rustdoc()
+        .input("c.rs")
+        .crate_type("rlib")
+        .extern_("d", "libd.rmeta")
+        .target("aarch64-unknown-none-softfloat")
+        .arg("--test")
+        .run_fail()
+        .assert_stderr_contains("mixing `-Zfixed-x18` will cause an ABI mismatch");
+
+    // rustdoc --test -Cunsafe-allow-abi-mismatch=... ignores the mismatch
+    rustdoc()
+        .input("c.rs")
+        .crate_type("rlib")
+        .extern_("d", "libd.rmeta")
+        .target("aarch64-unknown-none-softfloat")
+        .arg("--test")
+        .arg("-Cunsafe-allow-abi-mismatch=fixed-x18")
+        .run();
 }

tests/ui/drop/or-pattern-drop-order.rs

@@ -33,15 +33,15 @@ fn main() {
         // Drops are right-to-left: `z`, `y`, `x`.
         let (x, Ok(y) | Err(y), z);
         // Assignment order doesn't matter.
-        z = LogDrop(o, 1);
-        y = LogDrop(o, 2);
-        x = LogDrop(o, 3);
+        z = LogDrop(o, 1); //~ WARN value assigned to `z` is never read
+        y = LogDrop(o, 2); //~ WARN value assigned to `y` is never read
+        x = LogDrop(o, 3); //~ WARN value assigned to `x` is never read
     });
     assert_drop_order(1..=2, |o| {
         // The first or-pattern alternative determines the bindings' drop order: `y`, `x`.
         let ((true, x, y) | (false, y, x));
-        x = LogDrop(o, 2);
-        y = LogDrop(o, 1);
+        x = LogDrop(o, 2); //~ WARN value assigned to `x` is never read
+        y = LogDrop(o, 1); //~ WARN value assigned to `y` is never read
     });
 
     // `let pat = expr;` should have the same drop order.
@@ -61,15 +61,21 @@ fn main() {
     // `match` should have the same drop order.
     assert_drop_order(1..=3, |o| {
         // Drops are right-to-left: `z`, `y` `x`.
-        match (LogDrop(o, 3), Ok(LogDrop(o, 2)), LogDrop(o, 1)) { (x, Ok(y) | Err(y), z) => {} }
+        match (LogDrop(o, 3), Ok(LogDrop(o, 2)), LogDrop(o, 1)) {
+            (x, Ok(y) | Err(y), z) => {}
+        }
     });
     assert_drop_order(1..=2, |o| {
         // The first or-pattern alternative determines the bindings' drop order: `y`, `x`.
-        match (true, LogDrop(o, 2), LogDrop(o, 1)) { (true, x, y) | (false, y, x) => {} }
+        match (true, LogDrop(o, 2), LogDrop(o, 1)) {
+            (true, x, y) | (false, y, x) => {}
+        }
     });
     assert_drop_order(1..=2, |o| {
         // That drop order is used regardless of which or-pattern alternative matches: `y`, `x`.
-        match (false, LogDrop(o, 1), LogDrop(o, 2)) { (true, x, y) | (false, y, x) => {} }
+        match (false, LogDrop(o, 1), LogDrop(o, 2)) {
+            (true, x, y) | (false, y, x) => {}
+        }
     });
 
     // Function params are visited one-by-one, and the order of bindings within a param's pattern is

tests/ui/drop/or-pattern-drop-order.stderr

@@ -0,0 +1,43 @@
+warning: value assigned to `x` is never read
+  --> $DIR/or-pattern-drop-order.rs:43:9
+   |
+LL |         x = LogDrop(o, 2);
+   |         ^
+   |
+   = help: maybe it is overwritten before being read?
+   = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
+
+warning: value assigned to `y` is never read
+  --> $DIR/or-pattern-drop-order.rs:44:9
+   |
+LL |         y = LogDrop(o, 1);
+   |         ^
+   |
+   = help: maybe it is overwritten before being read?
+
+warning: value assigned to `x` is never read
+  --> $DIR/or-pattern-drop-order.rs:38:9
+   |
+LL |         x = LogDrop(o, 3);
+   |         ^
+   |
+   = help: maybe it is overwritten before being read?
+
+warning: value assigned to `y` is never read
+  --> $DIR/or-pattern-drop-order.rs:37:9
+   |
+LL |         y = LogDrop(o, 2);
+   |         ^
+   |
+   = help: maybe it is overwritten before being read?
+
+warning: value assigned to `z` is never read
+  --> $DIR/or-pattern-drop-order.rs:36:9
+   |
+LL |         z = LogDrop(o, 1);
+   |         ^
+   |
+   = help: maybe it is overwritten before being read?
+
+warning: 5 warnings emitted
+

tests/ui/lint/unused/unused-assign-148960.rs

@@ -0,0 +1,42 @@
+//@ check-fail
+#![deny(unused)]
+#![allow(dead_code)]
+
+fn test_one_extra_assign() {
+    let mut value = b"0".to_vec(); //~ ERROR value assigned to `value` is never read
+    value = b"1".to_vec();
+    println!("{:?}", value);
+}
+
+fn test_two_extra_assign() {
+    let mut x = 1; //~ ERROR value assigned to `x` is never read
+    x = 2; //~ ERROR value assigned to `x` is never read
+    x = 3;
+    println!("{}", x);
+}
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn test_indirect_assign() {
+    let mut p = Point { x: 1, y: 1 }; //~ ERROR value assigned to `p` is never read
+    p = Point { x: 2, y: 2 };
+    p.x = 3;
+    println!("{}", p.y);
+}
+
+struct Foo;
+
+impl Drop for Foo {
+    fn drop(&mut self) {}
+}
+
+// testcase for issue #148418
+fn test_unused_variable() {
+    let mut foo = Foo; //~ ERROR variable `foo` is assigned to, but never used
+    foo = Foo; //~ ERROR value assigned to `foo` is never read
+}
+
+fn main() {}

tests/ui/lint/unused/unused-assign-148960.stderr

@@ -0,0 +1,62 @@
+error: value assigned to `value` is never read
+  --> $DIR/unused-assign-148960.rs:6:21
+   |
+LL |     let mut value = b"0".to_vec();
+   |                     ^^^^^^^^^^^^^
+   |
+   = help: maybe it is overwritten before being read?
+note: the lint level is defined here
+  --> $DIR/unused-assign-148960.rs:2:9
+   |
+LL | #![deny(unused)]
+   |         ^^^^^^
+   = note: `#[deny(unused_assignments)]` implied by `#[deny(unused)]`
+
+error: value assigned to `x` is never read
+  --> $DIR/unused-assign-148960.rs:12:17
+   |
+LL |     let mut x = 1;
+   |                 ^
+   |
+   = help: maybe it is overwritten before being read?
+
+error: value assigned to `x` is never read
+  --> $DIR/unused-assign-148960.rs:13:5
+   |
+LL |     x = 2;
+   |     ^^^^^
+   |
+   = help: maybe it is overwritten before being read?
+
+error: value assigned to `p` is never read
+  --> $DIR/unused-assign-148960.rs:24:17
+   |
+LL |     let mut p = Point { x: 1, y: 1 };
+   |                 ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: maybe it is overwritten before being read?
+
+error: variable `foo` is assigned to, but never used
+  --> $DIR/unused-assign-148960.rs:38:9
+   |
+LL |     let mut foo = Foo;
+   |         ^^^^^^^
+   |
+   = note: consider using `_foo` instead
+   = note: `#[deny(unused_variables)]` implied by `#[deny(unused)]`
+help: you might have meant to pattern match on the similarly named struct `Foo`
+   |
+LL -     let mut foo = Foo;
+LL +     let Foo = Foo;
+   |
+
+error: value assigned to `foo` is never read
+  --> $DIR/unused-assign-148960.rs:39:5
+   |
+LL |     foo = Foo;
+   |     ^^^
+   |
+   = help: maybe it is overwritten before being read?
+
+error: aborting due to 6 previous errors
+

tests/ui/lint/unused/unused-var-in-unreachable-code.rs

@@ -0,0 +1,46 @@
+//@ check-pass
+
+#![allow(unreachable_code)]
+#![allow(dead_code)]
+#![warn(unused_variables)]
+
+fn after_todo() {
+    todo!("not implemented");
+
+    // This should not warn - the code is unreachable
+    let a = 1;
+    if a < 2 {
+        eprintln!("a: {}", a);
+    }
+}
+
+fn after_panic() {
+    panic!("oops");
+
+    // This should not warn - the code is unreachable
+    let b = 2;
+    println!("{}", b);
+}
+
+fn after_unimplemented() {
+    unimplemented!();
+
+    // This should not warn - the code is unreachable
+    let c = 3;
+    println!("{}", c);
+}
+
+fn after_unreachable() {
+    unsafe { std::hint::unreachable_unchecked() }
+
+    // This should not warn - the code is unreachable
+    let d = 4;
+    println!("{}", d);
+}
+
+fn reachable_unused() {
+    // This SHOULD warn - the code is reachable
+    let e = 5; //~ WARN unused variable: `e`
+}
+
+fn main() {}

tests/ui/lint/unused/unused-var-in-unreachable-code.stderr

@@ -0,0 +1,14 @@
+warning: unused variable: `e`
+  --> $DIR/unused-var-in-unreachable-code.rs:43:9
+   |
+LL |     let e = 5;
+   |         ^ help: if this is intentional, prefix it with an underscore: `_e`
+   |
+note: the lint level is defined here
+  --> $DIR/unused-var-in-unreachable-code.rs:5:9
+   |
+LL | #![warn(unused_variables)]
+   |         ^^^^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+

tests/ui/liveness/liveness-unused.rs

@@ -244,8 +244,8 @@ fn f10<T>(mut a: T, b: T) {
     //~^ ERROR value assigned to `a` is never read
 }
 
-fn f10b<T>(mut a: Box<T>, b: Box<T>) {
-    a = b;
+fn f10b<T>(mut a: Box<T>, b: Box<T>) { //~ ERROR variable `a` is assigned to, but never used
+    a = b; //~ ERROR value assigned to `a` is never read
 }
 
 // unused params warnings are not needed for intrinsic functions without bodies

tests/ui/liveness/liveness-unused.stderr

@@ -283,5 +283,21 @@ LL |     a = b;
    |
    = help: maybe it is overwritten before being read?
 
-error: aborting due to 34 previous errors; 1 warning emitted
+error: variable `a` is assigned to, but never used
+  --> $DIR/liveness-unused.rs:247:12
+   |
+LL | fn f10b<T>(mut a: Box<T>, b: Box<T>) {
+   |            ^^^^^
+   |
+   = note: consider using `_a` instead
+
+error: value assigned to `a` is never read
+  --> $DIR/liveness-unused.rs:248:5
+   |
+LL |     a = b;
+   |     ^
+   |
+   = help: maybe it is overwritten before being read?
+
+error: aborting due to 36 previous errors; 1 warning emitted
 

tests/ui/return/early-return-with-unreachable-code-24353.rs

@@ -4,7 +4,6 @@ fn main() {
     return ();
 
     let x = ();
-    //~^ WARN unused variable: `x`
     x
 }
 

tests/ui/return/early-return-with-unreachable-code-24353.stderr

@@ -1,10 +0,0 @@
-warning: unused variable: `x`
-  --> $DIR/early-return-with-unreachable-code-24353.rs:6:9
-   |
-LL |     let x = ();
-   |         ^ help: if this is intentional, prefix it with an underscore: `_x`
-   |
-   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
-
-warning: 1 warning emitted
-

tests/ui/suggestions/auxiliary/hidden-struct.rs

@@ -33,3 +33,6 @@ impl Marker for hidden::Foo {}
 impl Marker for hidden1::Bar {}
 impl Marker for Baz {}
 impl Marker for Quux {}
+
+
+pub use crate as library;

tests/ui/suggestions/dont-suggest-foreign-doc-hidden.rs

@@ -21,7 +21,12 @@ pub fn test4(_: Quux) {}
 
 fn test5<T: hidden_struct::Marker>() {}
 
+fn test6<T: hidden_struct::library::Marker>() {}
+
 fn main() {
     test5::<i32>();
     //~^ ERROR [E0277]
+
+    test6::<i32>();
+    //~^ ERROR [E0277]
 }

tests/ui/suggestions/dont-suggest-foreign-doc-hidden.stderr

@@ -38,7 +38,7 @@ LL + use hidden_struct::Quux;
    |
 
 error[E0277]: the trait bound `i32: Marker` is not satisfied
-  --> $DIR/dont-suggest-foreign-doc-hidden.rs:25:13
+  --> $DIR/dont-suggest-foreign-doc-hidden.rs:27:13
    |
 LL |     test5::<i32>();
    |             ^^^ the trait `Marker` is not implemented for `i32`
@@ -53,7 +53,23 @@ note: required by a bound in `test5`
 LL | fn test5<T: hidden_struct::Marker>() {}
    |             ^^^^^^^^^^^^^^^^^^^^^ required by this bound in `test5`
 
-error: aborting due to 5 previous errors
+error[E0277]: the trait bound `i32: Marker` is not satisfied
+  --> $DIR/dont-suggest-foreign-doc-hidden.rs:30:13
+   |
+LL |     test6::<i32>();
+   |             ^^^ the trait `Marker` is not implemented for `i32`
+   |
+   = help: the following other types implement trait `Marker`:
+             Baz
+             Option<u32>
+             Quux
+note: required by a bound in `test6`
+  --> $DIR/dont-suggest-foreign-doc-hidden.rs:24:13
+   |
+LL | fn test6<T: hidden_struct::library::Marker>() {}
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `test6`
+
+error: aborting due to 6 previous errors
 
 Some errors have detailed explanations: E0277, E0412.
 For more information about an error, try `rustc --explain E0277`.

triagebot.toml

@@ -1605,7 +1605,7 @@ labels = ["has-merge-commits", "S-waiting-on-author"]
 format = "rustc"
 project-name = "Rust"
 changelog-path = "RELEASES.md"
-changelog-branch = "master"
+changelog-branch = "main"
 
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