Merge from rustc

compiler/rustc_ast/src/ast.rs

@@ -2418,11 +2418,22 @@ impl InlineAsmOperand {
     }
 }
 
+#[derive(Clone, Copy, Encodable, Decodable, Debug, HashStable_Generic)]
+pub enum AsmMacro {
+    /// The `asm!` macro
+    Asm,
+    /// The `global_asm!` macro
+    GlobalAsm,
+    /// The `naked_asm!` macro
+    NakedAsm,
+}
+
 /// Inline assembly.
 ///
 /// E.g., `asm!("NOP");`.
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct InlineAsm {
+    pub asm_macro: AsmMacro,
     pub template: Vec<InlineAsmTemplatePiece>,
     pub template_strs: Box<[(Symbol, Option<Symbol>, Span)]>,
     pub operands: Vec<(InlineAsmOperand, Span)>,

compiler/rustc_ast/src/ast_traits.rs

@@ -153,7 +153,7 @@ impl HasTokens for StmtKind {
             StmtKind::Let(local) => local.tokens.as_ref(),
             StmtKind::Item(item) => item.tokens(),
             StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.tokens(),
-            StmtKind::Empty => return None,
+            StmtKind::Empty => None,
             StmtKind::MacCall(mac) => mac.tokens.as_ref(),
         }
     }
@@ -162,7 +162,7 @@ impl HasTokens for StmtKind {
             StmtKind::Let(local) => Some(&mut local.tokens),
             StmtKind::Item(item) => item.tokens_mut(),
             StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.tokens_mut(),
-            StmtKind::Empty => return None,
+            StmtKind::Empty => None,
             StmtKind::MacCall(mac) => Some(&mut mac.tokens),
         }
     }

compiler/rustc_ast/src/mut_visit.rs

@@ -1388,6 +1388,7 @@ fn walk_anon_const<T: MutVisitor>(vis: &mut T, AnonConst { id, value }: &mut Ano
 fn walk_inline_asm<T: MutVisitor>(vis: &mut T, asm: &mut InlineAsm) {
     // FIXME: Visit spans inside all this currently ignored stuff.
     let InlineAsm {
+        asm_macro: _,
         template: _,
         template_strs: _,
         operands,

compiler/rustc_ast/src/visit.rs

@@ -976,6 +976,7 @@ pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonCo
 
 pub fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm) -> V::Result {
     let InlineAsm {
+        asm_macro: _,
         template: _,
         template_strs: _,
         operands,

compiler/rustc_ast_lowering/src/asm.rs

@@ -474,8 +474,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         );
         let line_spans =
             self.arena.alloc_from_iter(asm.line_spans.iter().map(|span| self.lower_span(*span)));
-        let hir_asm =
-            hir::InlineAsm { template, template_strs, operands, options: asm.options, line_spans };
+        let hir_asm = hir::InlineAsm {
+            asm_macro: asm.asm_macro,
+            template,
+            template_strs,
+            operands,
+            options: asm.options,
+            line_spans,
+        };
         self.arena.alloc(hir_asm)
     }
 }

compiler/rustc_ast_lowering/src/expr.rs

@@ -1837,7 +1837,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             Safety::Default,
             sym::allow,
             sym::unreachable_code,
-            self.lower_span(span),
+            try_span,
         );
         let attrs: AttrVec = thin_vec![attr];
 

compiler/rustc_attr/src/builtin.rs

@@ -1240,5 +1240,5 @@ pub fn parse_confusables(attr: &Attribute) -> Option<Vec<Symbol>> {
         candidates.push(meta_lit.symbol);
     }
 
-    return Some(candidates);
+    Some(candidates)
 }

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3669,7 +3669,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 reinits.push(location);
                 return true;
             }
-            return false;
+            false
         };
 
         while let Some(location) = stack.pop() {

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -214,7 +214,7 @@ impl<'me, 'bccx, 'tcx> NllTypeRelating<'me, 'bccx, 'tcx> {
         let delegate = FnMutDelegate {
             regions: &mut |br: ty::BoundRegion| {
                 if let Some(ex_reg_var) = reg_map.get(&br) {
-                    return *ex_reg_var;
+                    *ex_reg_var
                 } else {
                     let ex_reg_var = self.next_existential_region_var(true, br.kind.get_name());
                     debug!(?ex_reg_var);

compiler/rustc_builtin_macros/src/asm.rs

@@ -3,6 +3,7 @@ use lint::BuiltinLintDiag;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter};
 use rustc_ast::tokenstream::TokenStream;
+use rustc_ast::AsmMacro;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_errors::PResult;
 use rustc_expand::base::*;
@@ -484,6 +485,7 @@ fn parse_reg<'a>(
 
 fn expand_preparsed_asm(
     ecx: &mut ExtCtxt<'_>,
+    asm_macro: ast::AsmMacro,
     args: AsmArgs,
 ) -> ExpandResult<Result<ast::InlineAsm, ErrorGuaranteed>, ()> {
     let mut template = vec![];
@@ -774,6 +776,7 @@ fn expand_preparsed_asm(
     }
 
     ExpandResult::Ready(Ok(ast::InlineAsm {
+        asm_macro,
         template,
         template_strs: template_strs.into_boxed_slice(),
         operands: args.operands,
@@ -790,7 +793,7 @@ pub(super) fn expand_asm<'cx>(
 ) -> MacroExpanderResult<'cx> {
     ExpandResult::Ready(match parse_args(ecx, sp, tts, false) {
         Ok(args) => {
-            let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, args) else {
+            let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, AsmMacro::Asm, args) else {
                 return ExpandResult::Retry(());
             };
             let expr = match mac {
@@ -819,7 +822,8 @@ pub(super) fn expand_naked_asm<'cx>(
 ) -> MacroExpanderResult<'cx> {
     ExpandResult::Ready(match parse_args(ecx, sp, tts, false) {
         Ok(args) => {
-            let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, args) else {
+            let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, AsmMacro::NakedAsm, args)
+            else {
                 return ExpandResult::Retry(());
             };
             let expr = match mac {
@@ -857,7 +861,8 @@ pub(super) fn expand_global_asm<'cx>(
 ) -> MacroExpanderResult<'cx> {
     ExpandResult::Ready(match parse_args(ecx, sp, tts, true) {
         Ok(args) => {
-            let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, args) else {
+            let ExpandResult::Ready(mac) = expand_preparsed_asm(ecx, AsmMacro::GlobalAsm, args)
+            else {
                 return ExpandResult::Retry(());
             };
             match mac {

compiler/rustc_builtin_macros/src/test.rs

@@ -277,6 +277,8 @@ pub(crate) fn expand_test_or_bench(
                 cx.attr_nested_word(sym::cfg, sym::test, attr_sp),
                 // #[rustc_test_marker = "test_case_sort_key"]
                 cx.attr_name_value_str(sym::rustc_test_marker, test_path_symbol, attr_sp),
+                // #[doc(hidden)]
+                cx.attr_nested_word(sym::doc, sym::hidden, attr_sp),
             ],
             // const $ident: test::TestDescAndFn =
             ast::ItemKind::Const(

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -326,8 +326,8 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
     let main_attr = ecx.attr_word(sym::rustc_main, sp);
     // #[coverage(off)]
     let coverage_attr = ecx.attr_nested_word(sym::coverage, sym::off, sp);
-    // #[allow(missing_docs)]
-    let missing_docs_attr = ecx.attr_nested_word(sym::allow, sym::missing_docs, sp);
+    // #[doc(hidden)]
+    let doc_hidden_attr = ecx.attr_nested_word(sym::doc, sym::hidden, sp);
 
     // pub fn main() { ... }
     let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(ThinVec::new()));
@@ -357,7 +357,7 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
 
     let main = P(ast::Item {
         ident: main_id,
-        attrs: thin_vec![main_attr, coverage_attr, missing_docs_attr],
+        attrs: thin_vec![main_attr, coverage_attr, doc_hidden_attr],
         id: ast::DUMMY_NODE_ID,
         kind: main,
         vis: ast::Visibility { span: sp, kind: ast::VisibilityKind::Public, tokens: None },

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -290,7 +290,7 @@ pub(crate) fn check_tied_features(
             }
         }
     }
-    return None;
+    None
 }
 
 /// Used to generate cfg variables and apply features

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -438,7 +438,7 @@ fn link_rlib<'a>(
         ab.add_file(&lib)
     }
 
-    return Ok(ab);
+    Ok(ab)
 }
 
 /// Extract all symbols defined in raw-dylib libraries, collated by library name.
@@ -1319,7 +1319,7 @@ fn link_sanitizer_runtime(
     fn find_sanitizer_runtime(sess: &Session, filename: &str) -> PathBuf {
         let path = sess.target_tlib_path.dir.join(filename);
         if path.exists() {
-            return sess.target_tlib_path.dir.clone();
+            sess.target_tlib_path.dir.clone()
         } else {
             let default_sysroot =
                 filesearch::get_or_default_sysroot().expect("Failed finding sysroot");
@@ -1327,7 +1327,7 @@ fn link_sanitizer_runtime(
                 &default_sysroot,
                 sess.opts.target_triple.triple(),
             );
-            return default_tlib;
+            default_tlib
         }
     }
 

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -1484,7 +1484,6 @@ impl<'a> Linker for L4Bender<'a> {
     fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[String]) {
         // ToDo, not implemented, copy from GCC
         self.sess.dcx().emit_warn(errors::L4BenderExportingSymbolsUnimplemented);
-        return;
     }
 
     fn subsystem(&mut self, subsystem: &str) {

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -171,10 +171,10 @@ pub(super) fn get_metadata_xcoff<'a>(path: &Path, data: &'a [u8]) -> Result<&'a
                 "Metadata at offset {offset} with size {len} is beyond .info section"
             ));
         }
-        return Ok(&info_data[offset..(offset + len)]);
+        Ok(&info_data[offset..(offset + len)])
     } else {
-        return Err(format!("Unable to find symbol {AIX_METADATA_SYMBOL_NAME}"));
-    };
+        Err(format!("Unable to find symbol {AIX_METADATA_SYMBOL_NAME}"))
+    }
 }
 
 pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static>> {
@@ -413,7 +413,7 @@ fn macho_object_build_version_for_target(target: &Target) -> object::write::Mach
 
 /// Is Apple's CPU subtype `arm64e`s
 fn macho_is_arm64e(target: &Target) -> bool {
-    return target.llvm_target.starts_with("arm64e");
+    target.llvm_target.starts_with("arm64e")
 }
 
 pub enum MetadataPosition {

compiler/rustc_const_eval/src/interpret/call.rs

@@ -235,13 +235,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         if self.layout_compat(caller_abi.layout, callee_abi.layout)? {
             // Ensure that our checks imply actual ABI compatibility for this concrete call.
             assert!(caller_abi.eq_abi(callee_abi));
-            return Ok(true);
+            Ok(true)
         } else {
             trace!(
                 "check_argument_compat: incompatible ABIs:\ncaller: {:?}\ncallee: {:?}",
                 caller_abi, callee_abi
             );
-            return Ok(false);
+            Ok(false)
         }
     }
 

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -433,6 +433,7 @@ impl<'tcx, Prov: Provenance> Projectable<'tcx, Prov> for ImmTy<'tcx, Prov> {
         Ok(self.offset_(offset, layout, ecx))
     }
 
+    #[inline(always)]
     fn to_op<M: Machine<'tcx, Provenance = Prov>>(
         &self,
         _ecx: &InterpCx<'tcx, M>,
@@ -522,6 +523,7 @@ impl<'tcx, Prov: Provenance> Projectable<'tcx, Prov> for OpTy<'tcx, Prov> {
         }
     }
 
+    #[inline(always)]
     fn to_op<M: Machine<'tcx, Provenance = Prov>>(
         &self,
         _ecx: &InterpCx<'tcx, M>,

compiler/rustc_const_eval/src/interpret/operator.rs

@@ -303,8 +303,10 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let pointee_layout = self.layout_of(pointee_ty)?;
                 assert!(pointee_layout.abi.is_sized());
 
-                // We cannot overflow i64 as a type's size must be <= isize::MAX.
+                // The size always fits in `i64` as it can be at most `isize::MAX`.
                 let pointee_size = i64::try_from(pointee_layout.size.bytes()).unwrap();
+                // This uses the same type as `right`, which can be `isize` or `usize`.
+                // `pointee_size` is guaranteed to fit into both types.
                 let pointee_size = ImmTy::from_int(pointee_size, right.layout);
                 // Multiply element size and element count.
                 let (val, overflowed) = self
@@ -316,6 +318,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 }
 
                 let offset_bytes = val.to_target_isize(self)?;
+                if !right.layout.abi.is_signed() && offset_bytes < 0 {
+                    // We were supposed to do an unsigned offset but the result is negative -- this
+                    // can only mean that the cast wrapped around.
+                    throw_ub!(PointerArithOverflow)
+                }
                 let offset_ptr = self.ptr_offset_inbounds(ptr, offset_bytes)?;
                 Ok(ImmTy::from_scalar(Scalar::from_maybe_pointer(offset_ptr, self), left.layout))
             }

compiler/rustc_const_eval/src/interpret/place.rs

@@ -166,6 +166,7 @@ impl<'tcx, Prov: Provenance> Projectable<'tcx, Prov> for MPlaceTy<'tcx, Prov> {
         Ok(MPlaceTy { mplace: self.mplace.offset_with_meta_(offset, mode, meta, ecx)?, layout })
     }
 
+    #[inline(always)]
     fn to_op<M: Machine<'tcx, Provenance = Prov>>(
         &self,
         _ecx: &InterpCx<'tcx, M>,
@@ -299,6 +300,7 @@ impl<'tcx, Prov: Provenance> Projectable<'tcx, Prov> for PlaceTy<'tcx, Prov> {
         })
     }
 
+    #[inline(always)]
     fn to_op<M: Machine<'tcx, Provenance = Prov>>(
         &self,
         ecx: &InterpCx<'tcx, M>,
@@ -560,6 +562,7 @@ where
 
     /// Given a place, returns either the underlying mplace or a reference to where the value of
     /// this place is stored.
+    #[inline(always)]
     fn as_mplace_or_mutable_local(
         &mut self,
         place: &PlaceTy<'tcx, M::Provenance>,

compiler/rustc_errors/src/diagnostic.rs

@@ -8,11 +8,11 @@ use std::thread::panicking;
 
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_error_messages::{fluent_value_from_str_list_sep_by_and, FluentValue};
-use rustc_lint_defs::{Applicability, LintExpectationId};
+use rustc_lint_defs::Applicability;
 use rustc_macros::{Decodable, Encodable};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::Symbol;
-use rustc_span::{AttrId, Span, DUMMY_SP};
+use rustc_span::{Span, DUMMY_SP};
 use tracing::debug;
 
 use crate::snippet::Style;
@@ -354,26 +354,6 @@ impl DiagInner {
         }
     }
 
-    pub(crate) fn update_unstable_expectation_id(
-        &mut self,
-        unstable_to_stable: &FxIndexMap<AttrId, LintExpectationId>,
-    ) {
-        if let Level::Expect(expectation_id) | Level::ForceWarning(Some(expectation_id)) =
-            &mut self.level
-            && let LintExpectationId::Unstable { attr_id, lint_index } = *expectation_id
-        {
-            // The unstable to stable map only maps the unstable `AttrId` to a stable `HirId` with an attribute index.
-            // The lint index inside the attribute is manually transferred here.
-            let Some(stable_id) = unstable_to_stable.get(&attr_id) else {
-                panic!("{expectation_id:?} must have a matching stable id")
-            };
-
-            let mut stable_id = *stable_id;
-            stable_id.set_lint_index(lint_index);
-            *expectation_id = stable_id;
-        }
-    }
-
     /// Indicates whether this diagnostic should show up in cargo's future breakage report.
     pub(crate) fn has_future_breakage(&self) -> bool {
         matches!(self.is_lint, Some(IsLint { has_future_breakage: true, .. }))

compiler/rustc_errors/src/lib.rs

@@ -69,7 +69,7 @@ use rustc_macros::{Decodable, Encodable};
 pub use rustc_span::fatal_error::{FatalError, FatalErrorMarker};
 use rustc_span::source_map::SourceMap;
 pub use rustc_span::ErrorGuaranteed;
-use rustc_span::{AttrId, Loc, Span, DUMMY_SP};
+use rustc_span::{Loc, Span, DUMMY_SP};
 pub use snippet::Style;
 // Used by external projects such as `rust-gpu`.
 // See https://github.com/rust-lang/rust/pull/115393.
@@ -497,28 +497,18 @@ struct DiagCtxtInner {
 
     future_breakage_diagnostics: Vec<DiagInner>,
 
-    /// The [`Self::unstable_expect_diagnostics`] should be empty when this struct is
-    /// dropped. However, it can have values if the compilation is stopped early
-    /// or is only partially executed. To avoid ICEs, like in rust#94953 we only
-    /// check if [`Self::unstable_expect_diagnostics`] is empty, if the expectation ids
-    /// have been converted.
-    check_unstable_expect_diagnostics: bool,
-
-    /// Expected [`DiagInner`][struct@diagnostic::DiagInner]s store a [`LintExpectationId`] as part
-    /// of the lint level. [`LintExpectationId`]s created early during the compilation
-    /// (before `HirId`s have been defined) are not stable and can therefore not be
-    /// stored on disk. This buffer stores these diagnostics until the ID has been
-    /// replaced by a stable [`LintExpectationId`]. The [`DiagInner`][struct@diagnostic::DiagInner]s
-    /// are submitted for storage and added to the list of fulfilled expectations.
-    unstable_expect_diagnostics: Vec<DiagInner>,
-
     /// expected diagnostic will have the level `Expect` which additionally
     /// carries the [`LintExpectationId`] of the expectation that can be
     /// marked as fulfilled. This is a collection of all [`LintExpectationId`]s
     /// that have been marked as fulfilled this way.
     ///
+    /// Emitting expectations after having stolen this field can happen. In particular, an
+    /// `#[expect(warnings)]` can easily make the `UNFULFILLED_LINT_EXPECTATIONS` lint expect
+    /// itself. To avoid needless complexity in this corner case, we tolerate failing to track
+    /// those expectations.
+    ///
     /// [RFC-2383]: https://rust-lang.github.io/rfcs/2383-lint-reasons.html
-    fulfilled_expectations: FxHashSet<LintExpectationId>,
+    fulfilled_expectations: FxIndexSet<LintExpectationId>,
 
     /// The file where the ICE information is stored. This allows delayed_span_bug backtraces to be
     /// stored along side the main panic backtrace.
@@ -605,13 +595,6 @@ impl Drop for DiagCtxtInner {
                 );
             }
         }
-
-        if self.check_unstable_expect_diagnostics {
-            assert!(
-                self.unstable_expect_diagnostics.is_empty(),
-                "all diagnostics with unstable expectations should have been converted",
-            );
-        }
     }
 }
 
@@ -740,8 +723,6 @@ impl DiagCtxt {
             emitted_diagnostics,
             stashed_diagnostics,
             future_breakage_diagnostics,
-            check_unstable_expect_diagnostics,
-            unstable_expect_diagnostics,
             fulfilled_expectations,
             ice_file: _,
         } = inner.deref_mut();
@@ -761,8 +742,6 @@ impl DiagCtxt {
         *emitted_diagnostics = Default::default();
         *stashed_diagnostics = Default::default();
         *future_breakage_diagnostics = Default::default();
-        *check_unstable_expect_diagnostics = false;
-        *unstable_expect_diagnostics = Default::default();
         *fulfilled_expectations = Default::default();
     }
 
@@ -1094,44 +1073,10 @@ impl<'a> DiagCtxtHandle<'a> {
         inner.emitter.emit_unused_externs(lint_level, unused_externs)
     }
 
-    pub fn update_unstable_expectation_id(
-        &self,
-        unstable_to_stable: FxIndexMap<AttrId, LintExpectationId>,
-    ) {
-        let mut inner = self.inner.borrow_mut();
-        let diags = std::mem::take(&mut inner.unstable_expect_diagnostics);
-        inner.check_unstable_expect_diagnostics = true;
-
-        if !diags.is_empty() {
-            inner.suppressed_expected_diag = true;
-            for mut diag in diags.into_iter() {
-                diag.update_unstable_expectation_id(&unstable_to_stable);
-
-                // Here the diagnostic is given back to `emit_diagnostic` where it was first
-                // intercepted. Now it should be processed as usual, since the unstable expectation
-                // id is now stable.
-                inner.emit_diagnostic(diag, self.tainted_with_errors);
-            }
-        }
-
-        inner
-            .stashed_diagnostics
-            .values_mut()
-            .for_each(|(diag, _guar)| diag.update_unstable_expectation_id(&unstable_to_stable));
-        inner
-            .future_breakage_diagnostics
-            .iter_mut()
-            .for_each(|diag| diag.update_unstable_expectation_id(&unstable_to_stable));
-    }
-
     /// This methods steals all [`LintExpectationId`]s that are stored inside
     /// [`DiagCtxtInner`] and indicate that the linked expectation has been fulfilled.
     #[must_use]
-    pub fn steal_fulfilled_expectation_ids(&self) -> FxHashSet<LintExpectationId> {
-        assert!(
-            self.inner.borrow().unstable_expect_diagnostics.is_empty(),
-            "`DiagCtxtInner::unstable_expect_diagnostics` should be empty at this point",
-        );
+    pub fn steal_fulfilled_expectation_ids(&self) -> FxIndexSet<LintExpectationId> {
         std::mem::take(&mut self.inner.borrow_mut().fulfilled_expectations)
     }
 
@@ -1440,8 +1385,6 @@ impl DiagCtxtInner {
             emitted_diagnostics: Default::default(),
             stashed_diagnostics: Default::default(),
             future_breakage_diagnostics: Vec::new(),
-            check_unstable_expect_diagnostics: false,
-            unstable_expect_diagnostics: Vec::new(),
             fulfilled_expectations: Default::default(),
             ice_file: None,
         }
@@ -1471,24 +1414,6 @@ impl DiagCtxtInner {
         mut diagnostic: DiagInner,
         taint: Option<&Cell<Option<ErrorGuaranteed>>>,
     ) -> Option<ErrorGuaranteed> {
-        match diagnostic.level {
-            Expect(expect_id) | ForceWarning(Some(expect_id)) => {
-                // The `LintExpectationId` can be stable or unstable depending on when it was
-                // created. Diagnostics created before the definition of `HirId`s are unstable and
-                // can not yet be stored. Instead, they are buffered until the `LintExpectationId`
-                // is replaced by a stable one by the `LintLevelsBuilder`.
-                if let LintExpectationId::Unstable { .. } = expect_id {
-                    // We don't call TRACK_DIAGNOSTIC because we wait for the
-                    // unstable ID to be updated, whereupon the diagnostic will be
-                    // passed into this method again.
-                    self.unstable_expect_diagnostics.push(diagnostic);
-                    return None;
-                }
-                // Continue through to the `Expect`/`ForceWarning` case below.
-            }
-            _ => {}
-        }
-
         if diagnostic.has_future_breakage() {
             // Future breakages aren't emitted if they're `Level::Allow` or
             // `Level::Expect`, but they still need to be constructed and
@@ -1564,9 +1489,6 @@ impl DiagCtxtInner {
                 return None;
             }
             Expect(expect_id) | ForceWarning(Some(expect_id)) => {
-                if let LintExpectationId::Unstable { .. } = expect_id {
-                    unreachable!(); // this case was handled at the top of this function
-                }
                 self.fulfilled_expectations.insert(expect_id);
                 if let Expect(_) = diagnostic.level {
                     // Nothing emitted here for expected lints.

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -773,18 +773,20 @@ fn extract_symbol_from_pnr<'a>(
     match pnr {
         ParseNtResult::Ident(nt_ident, is_raw) => {
             if let IdentIsRaw::Yes = is_raw {
-                return Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR));
+                Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR))
+            } else {
+                Ok(nt_ident.name)
             }
-            return Ok(nt_ident.name);
         }
         ParseNtResult::Tt(TokenTree::Token(
             Token { kind: TokenKind::Ident(symbol, is_raw), .. },
             _,
         )) => {
             if let IdentIsRaw::Yes = is_raw {
-                return Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR));
+                Err(dcx.struct_span_err(span_err, RAW_IDENT_ERR))
+            } else {
+                Ok(*symbol)
             }
-            return Ok(*symbol);
         }
         ParseNtResult::Tt(TokenTree::Token(
             Token {
@@ -792,15 +794,13 @@ fn extract_symbol_from_pnr<'a>(
                 ..
             },
             _,
-        )) => {
-            return Ok(*symbol);
-        }
+        )) => Ok(*symbol),
         ParseNtResult::Nt(nt)
             if let Nonterminal::NtLiteral(expr) = &**nt
                 && let ExprKind::Lit(Lit { kind: LitKind::Str, symbol, suffix: None }) =
                     &expr.kind =>
         {
-            return Ok(*symbol);
+            Ok(*symbol)
         }
         _ => Err(dcx
             .struct_err(

compiler/rustc_hir/src/hir.rs

@@ -2927,6 +2927,7 @@ impl<'hir> InlineAsmOperand<'hir> {
 
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct InlineAsm<'hir> {
+    pub asm_macro: ast::AsmMacro,
     pub template: &'hir [InlineAsmTemplatePiece],
     pub template_strs: &'hir [(Symbol, Option<Symbol>, Span)],
     pub operands: &'hir [(InlineAsmOperand<'hir>, Span)],

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1038,7 +1038,7 @@ fn report_trait_method_mismatch<'tcx>(
         false,
     );
 
-    return diag.emit();
+    diag.emit()
 }
 
 fn check_region_bounds_on_impl_item<'tcx>(

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -274,7 +274,7 @@ fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<()
                         return false;
                     }
 
-                    return true;
+                    true
                 })
                 .collect::<Vec<_>>();
 

compiler/rustc_hir_typeck/src/_match.rs

@@ -389,7 +389,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             {
                 // check that the `if` expr without `else` is the fn body's expr
                 if expr.span == sp {
-                    return self.get_fn_decl(hir_id).map(|(_, fn_decl, _)| {
+                    return self.get_fn_decl(hir_id).map(|(_, fn_decl)| {
                         let (ty, span) = match fn_decl.output {
                             hir::FnRetTy::DefaultReturn(span) => ("()".to_string(), span),
                             hir::FnRetTy::Return(ty) => (ty_to_string(&self.tcx, ty), ty.span),

compiler/rustc_hir_typeck/src/closure.rs

@@ -605,7 +605,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             Abi::Rust,
         ));
 
-        return Some(ExpectedSig { cause_span, sig });
+        Some(ExpectedSig { cause_span, sig })
     }
 
     fn sig_of_closure(

compiler/rustc_hir_typeck/src/coercion.rs

@@ -1860,10 +1860,10 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         };
 
         // If this is due to an explicit `return`, suggest adding a return type.
-        if let Some((fn_id, fn_decl, can_suggest)) = fcx.get_fn_decl(block_or_return_id)
+        if let Some((fn_id, fn_decl)) = fcx.get_fn_decl(block_or_return_id)
             && !due_to_block
         {
-            fcx.suggest_missing_return_type(&mut err, fn_decl, expected, found, can_suggest, fn_id);
+            fcx.suggest_missing_return_type(&mut err, fn_decl, expected, found, fn_id);
         }
 
         // If this is due to a block, then maybe we forgot a `return`/`break`.

compiler/rustc_hir_typeck/src/demand.rs

@@ -1042,7 +1042,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return true;
             }
         }
-        return false;
+        false
     }
 
     fn explain_self_literal(

compiler/rustc_hir_typeck/src/expr.rs

@@ -774,7 +774,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.ret_coercion_span.set(Some(expr.span));
             }
             let cause = self.cause(expr.span, ObligationCauseCode::ReturnNoExpression);
-            if let Some((_, fn_decl, _)) = self.get_fn_decl(expr.hir_id) {
+            if let Some((_, fn_decl)) = self.get_fn_decl(expr.hir_id) {
                 coercion.coerce_forced_unit(
                     self,
                     &cause,

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -30,7 +30,7 @@ use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
-use rustc_span::symbol::{kw, sym};
+use rustc_span::symbol::kw;
 use rustc_span::Span;
 use rustc_target::abi::FieldIdx;
 use rustc_trait_selection::error_reporting::infer::need_type_info::TypeAnnotationNeeded;
@@ -859,38 +859,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )
     }
 
-    /// Given a `HirId`, return the `HirId` of the enclosing function, its `FnDecl`, and whether a
-    /// suggestion can be made, `None` otherwise.
+    /// Given a `HirId`, return the `HirId` of the enclosing function and its `FnDecl`.
     pub(crate) fn get_fn_decl(
         &self,
         blk_id: HirId,
-    ) -> Option<(LocalDefId, &'tcx hir::FnDecl<'tcx>, bool)> {
+    ) -> Option<(LocalDefId, &'tcx hir::FnDecl<'tcx>)> {
         // Get enclosing Fn, if it is a function or a trait method, unless there's a `loop` or
         // `while` before reaching it, as block tail returns are not available in them.
         self.tcx.hir().get_fn_id_for_return_block(blk_id).and_then(|item_id| {
             match self.tcx.hir_node(item_id) {
                 Node::Item(&hir::Item {
-                    ident,
-                    kind: hir::ItemKind::Fn(ref sig, ..),
-                    owner_id,
-                    ..
-                }) => {
-                    // This is less than ideal, it will not suggest a return type span on any
-                    // method called `main`, regardless of whether it is actually the entry point,
-                    // but it will still present it as the reason for the expected type.
-                    Some((owner_id.def_id, sig.decl, ident.name != sym::main))
-                }
+                    kind: hir::ItemKind::Fn(ref sig, ..), owner_id, ..
+                }) => Some((owner_id.def_id, sig.decl)),
                 Node::TraitItem(&hir::TraitItem {
                     kind: hir::TraitItemKind::Fn(ref sig, ..),
                     owner_id,
                     ..
-                }) => Some((owner_id.def_id, sig.decl, true)),
-                // FIXME: Suggestable if this is not a trait implementation
+                }) => Some((owner_id.def_id, sig.decl)),
                 Node::ImplItem(&hir::ImplItem {
                     kind: hir::ImplItemKind::Fn(ref sig, ..),
                     owner_id,
                     ..
-                }) => Some((owner_id.def_id, sig.decl, false)),
+                }) => Some((owner_id.def_id, sig.decl)),
                 Node::Expr(&hir::Expr {
                     hir_id,
                     kind: hir::ExprKind::Closure(&hir::Closure { def_id, kind, fn_decl, .. }),
@@ -901,33 +891,30 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             // FIXME(async_closures): Implement this.
                             return None;
                         }
-                        hir::ClosureKind::Closure => Some((def_id, fn_decl, true)),
+                        hir::ClosureKind::Closure => Some((def_id, fn_decl)),
                         hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
                             _,
                             hir::CoroutineSource::Fn,
                         )) => {
-                            let (ident, sig, owner_id) = match self.tcx.parent_hir_node(hir_id) {
+                            let (sig, owner_id) = match self.tcx.parent_hir_node(hir_id) {
                                 Node::Item(&hir::Item {
-                                    ident,
                                     kind: hir::ItemKind::Fn(ref sig, ..),
                                     owner_id,
                                     ..
-                                }) => (ident, sig, owner_id),
+                                }) => (sig, owner_id),
                                 Node::TraitItem(&hir::TraitItem {
-                                    ident,
                                     kind: hir::TraitItemKind::Fn(ref sig, ..),
                                     owner_id,
                                     ..
-                                }) => (ident, sig, owner_id),
+                                }) => (sig, owner_id),
                                 Node::ImplItem(&hir::ImplItem {
-                                    ident,
                                     kind: hir::ImplItemKind::Fn(ref sig, ..),
                                     owner_id,
                                     ..
-                                }) => (ident, sig, owner_id),
+                                }) => (sig, owner_id),
                                 _ => return None,
                             };
-                            Some((owner_id.def_id, sig.decl, ident.name != sym::main))
+                            Some((owner_id.def_id, sig.decl))
                         }
                         _ => None,
                     }

compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs

@@ -307,7 +307,7 @@ impl<'tcx> ArgMatrix<'tcx> {
                 permutation.into_iter().map(|x| x.unwrap()).collect();
             return Some(Issue::Permutation(final_permutation));
         }
-        return None;
+        None
     }
 
     // Obviously, detecting exact user intention is impossible, so the goal here is to
@@ -410,6 +410,6 @@ impl<'tcx> ArgMatrix<'tcx> {
         // sort errors with same type by the order they appear in the source
         // so that suggestion will be handled properly, see #112507
         errors.sort();
-        return (errors, matched_inputs);
+        (errors, matched_inputs)
     }
 }

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1873,7 +1873,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // that highlight errors inline.
                     let mut sp = blk.span;
                     let mut fn_span = None;
-                    if let Some((fn_def_id, decl, _)) = self.get_fn_decl(blk.hir_id) {
+                    if let Some((fn_def_id, decl)) = self.get_fn_decl(blk.hir_id) {
                         let ret_sp = decl.output.span();
                         if let Some(block_sp) = self.parent_item_span(blk.hir_id) {
                             // HACK: on some cases (`ui/liveness/liveness-issue-2163.rs`) the

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -79,9 +79,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // `break` type mismatches provide better context for tail `loop` expressions.
             return false;
         }
-        if let Some((fn_id, fn_decl, can_suggest)) = self.get_fn_decl(blk_id) {
+        if let Some((fn_id, fn_decl)) = self.get_fn_decl(blk_id) {
             pointing_at_return_type =
-                self.suggest_missing_return_type(err, fn_decl, expected, found, can_suggest, fn_id);
+                self.suggest_missing_return_type(err, fn_decl, expected, found, fn_id);
             self.suggest_missing_break_or_return_expr(
                 err, expr, fn_decl, expected, found, blk_id, fn_id,
             );
@@ -813,7 +813,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         fn_decl: &hir::FnDecl<'tcx>,
         expected: Ty<'tcx>,
         found: Ty<'tcx>,
-        can_suggest: bool,
         fn_id: LocalDefId,
     ) -> bool {
         // Can't suggest `->` on a block-like coroutine
@@ -826,28 +825,26 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let found =
             self.resolve_numeric_literals_with_default(self.resolve_vars_if_possible(found));
         // Only suggest changing the return type for methods that
-        // haven't set a return type at all (and aren't `fn main()` or an impl).
+        // haven't set a return type at all (and aren't `fn main()`, impl or closure).
         match &fn_decl.output {
-            &hir::FnRetTy::DefaultReturn(span) if expected.is_unit() && !can_suggest => {
-                // `fn main()` must return `()`, do not suggest changing return type
-                err.subdiagnostic(errors::ExpectedReturnTypeLabel::Unit { span });
-                return true;
-            }
+            // For closure with default returns, don't suggest adding return type
+            &hir::FnRetTy::DefaultReturn(_) if self.tcx.is_closure_like(fn_id.to_def_id()) => {}
             &hir::FnRetTy::DefaultReturn(span) if expected.is_unit() => {
-                if let Some(found) = found.make_suggestable(self.tcx, false, None) {
+                if !self.can_add_return_type(fn_id) {
+                    err.subdiagnostic(errors::ExpectedReturnTypeLabel::Unit { span });
+                } else if let Some(found) = found.make_suggestable(self.tcx, false, None) {
                     err.subdiagnostic(errors::AddReturnTypeSuggestion::Add {
                         span,
                         found: found.to_string(),
                     });
-                    return true;
                 } else if let Some(sugg) = suggest_impl_trait(self, self.param_env, found) {
                     err.subdiagnostic(errors::AddReturnTypeSuggestion::Add { span, found: sugg });
-                    return true;
                 } else {
                     // FIXME: if `found` could be `impl Iterator` we should suggest that.
                     err.subdiagnostic(errors::AddReturnTypeSuggestion::MissingHere { span });
-                    return true;
                 }
+
+                return true;
             }
             hir::FnRetTy::Return(hir_ty) => {
                 if let hir::TyKind::OpaqueDef(item_id, ..) = hir_ty.kind
@@ -905,6 +902,32 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         false
     }
 
+    /// Checks whether we can add a return type to a function.
+    /// Assumes given function doesn't have a explicit return type.
+    fn can_add_return_type(&self, fn_id: LocalDefId) -> bool {
+        match self.tcx.hir_node_by_def_id(fn_id) {
+            Node::Item(&hir::Item { ident, .. }) => {
+                // This is less than ideal, it will not suggest a return type span on any
+                // method called `main`, regardless of whether it is actually the entry point,
+                // but it will still present it as the reason for the expected type.
+                ident.name != sym::main
+            }
+            Node::ImplItem(item) => {
+                // If it doesn't impl a trait, we can add a return type
+                let Node::Item(&hir::Item {
+                    kind: hir::ItemKind::Impl(&hir::Impl { of_trait, .. }),
+                    ..
+                }) = self.tcx.parent_hir_node(item.hir_id())
+                else {
+                    unreachable!();
+                };
+
+                of_trait.is_none()
+            }
+            _ => true,
+        }
+    }
+
     fn try_note_caller_chooses_ty_for_ty_param(
         &self,
         diag: &mut Diag<'_>,
@@ -2028,7 +2051,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let span = expr.span.find_oldest_ancestor_in_same_ctxt();
         err.span_suggestion_verbose(span.shrink_to_hi(), msg, sugg, Applicability::HasPlaceholders);
-        return true;
+        true
     }
 
     pub(crate) fn suggest_coercing_result_via_try_operator(

compiler/rustc_hir_typeck/src/lib.rs

@@ -43,7 +43,7 @@ pub use coercion::can_coerce;
 use fn_ctxt::FnCtxt;
 use rustc_data_structures::unord::UnordSet;
 use rustc_errors::codes::*;
-use rustc_errors::{struct_span_code_err, Applicability, ErrorGuaranteed};
+use rustc_errors::{pluralize, struct_span_code_err, Applicability, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::Visitor;
@@ -423,6 +423,36 @@ fn report_unexpected_variant_res(
             err.multipart_suggestion_verbose(descr, suggestion, Applicability::MaybeIncorrect);
             err
         }
+        Res::Def(DefKind::Variant, _) if expr.is_none() => {
+            err.span_label(span, format!("not a {expected}"));
+
+            let fields = &tcx.expect_variant_res(res).fields.raw;
+            let span = qpath.span().shrink_to_hi().to(span.shrink_to_hi());
+            let (msg, sugg) = if fields.is_empty() {
+                ("use the struct variant pattern syntax".to_string(), " {}".to_string())
+            } else {
+                let msg = format!(
+                    "the struct variant's field{s} {are} being ignored",
+                    s = pluralize!(fields.len()),
+                    are = pluralize!("is", fields.len())
+                );
+                let fields = fields
+                    .iter()
+                    .map(|field| format!("{}: _", field.name.to_ident_string()))
+                    .collect::<Vec<_>>()
+                    .join(", ");
+                let sugg = format!(" {{ {} }}", fields);
+                (msg, sugg)
+            };
+
+            err.span_suggestion_verbose(
+                qpath.span().shrink_to_hi().to(span.shrink_to_hi()),
+                msg,
+                sugg,
+                Applicability::HasPlaceholders,
+            );
+            err
+        }
         _ => err.with_span_label(span, format!("not a {expected}")),
     }
     .emit()

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -1317,7 +1317,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let actual_prefix = rcvr_ty.prefix_string(self.tcx);
                 info!("unimplemented_traits.len() == {}", unimplemented_traits.len());
                 let mut long_ty_file = None;
-                let (primary_message, label) = if unimplemented_traits.len() == 1
+                let (primary_message, label, notes) = if unimplemented_traits.len() == 1
                     && unimplemented_traits_only
                 {
                     unimplemented_traits
@@ -1327,16 +1327,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             if trait_ref.self_ty().references_error() || rcvr_ty.references_error()
                             {
                                 // Avoid crashing.
-                                return (None, None);
+                                return (None, None, Vec::new());
                             }
-                            let OnUnimplementedNote { message, label, .. } = self
+                            let OnUnimplementedNote { message, label, notes, .. } = self
                                 .err_ctxt()
                                 .on_unimplemented_note(trait_ref, &obligation, &mut long_ty_file);
-                            (message, label)
+                            (message, label, notes)
                         })
                         .unwrap()
                 } else {
-                    (None, None)
+                    (None, None, Vec::new())
                 };
                 let primary_message = primary_message.unwrap_or_else(|| {
                     format!(
@@ -1363,6 +1363,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         "the following trait bounds were not satisfied:\n{bound_list}"
                     ));
                 }
+                for note in notes {
+                    err.note(note);
+                }
+
                 suggested_derive = self.suggest_derive(&mut err, unsatisfied_predicates);
 
                 unsatisfied_bounds = true;

compiler/rustc_infer/src/infer/mod.rs

@@ -1481,7 +1481,7 @@ impl<'tcx> InferCtxt<'tcx> {
         // This hoists the borrow/release out of the loop body.
         let inner = self.inner.try_borrow();
 
-        return move |infer_var: TyOrConstInferVar| match (infer_var, &inner) {
+        move |infer_var: TyOrConstInferVar| match (infer_var, &inner) {
             (TyOrConstInferVar::Ty(ty_var), Ok(inner)) => {
                 use self::type_variable::TypeVariableValue;
 
@@ -1491,7 +1491,7 @@ impl<'tcx> InferCtxt<'tcx> {
                 )
             }
             _ => false,
-        };
+        }
     }
 
     /// `ty_or_const_infer_var_changed` is equivalent to one of these two:

compiler/rustc_infer/src/infer/relate/generalize.rs

@@ -259,11 +259,11 @@ impl<'tcx> InferCtxt<'tcx> {
             structurally_relate_aliases,
             root_vid,
             for_universe,
-            ambient_variance,
             root_term: source_term.into(),
+            ambient_variance,
             in_alias: false,
-            has_unconstrained_ty_var: false,
             cache: Default::default(),
+            has_unconstrained_ty_var: false,
         };
 
         let value_may_be_infer = generalizer.relate(source_term, source_term)?;
@@ -304,14 +304,12 @@ struct Generalizer<'me, 'tcx> {
     /// we reject the relation.
     for_universe: ty::UniverseIndex,
 
-    /// After we generalize this type, we are going to relate it to
-    /// some other type. What will be the variance at this point?
-    ambient_variance: ty::Variance,
-
     /// The root term (const or type) we're generalizing. Used for cycle errors.
     root_term: Term<'tcx>,
 
-    cache: SsoHashMap<Ty<'tcx>, Ty<'tcx>>,
+    /// After we generalize this type, we are going to relate it to
+    /// some other type. What will be the variance at this point?
+    ambient_variance: ty::Variance,
 
     /// This is set once we're generalizing the arguments of an alias.
     ///
@@ -320,6 +318,8 @@ struct Generalizer<'me, 'tcx> {
     /// hold by either normalizing the outer or the inner associated type.
     in_alias: bool,
 
+    cache: SsoHashMap<(Ty<'tcx>, ty::Variance, bool), Ty<'tcx>>,
+
     /// See the field `has_unconstrained_ty_var` in `Generalization`.
     has_unconstrained_ty_var: bool,
 }
@@ -451,7 +451,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Generalizer<'_, 'tcx> {
     fn tys(&mut self, t: Ty<'tcx>, t2: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         assert_eq!(t, t2); // we are misusing TypeRelation here; both LHS and RHS ought to be ==
 
-        if let Some(&result) = self.cache.get(&t) {
+        if let Some(&result) = self.cache.get(&(t, self.ambient_variance, self.in_alias)) {
             return Ok(result);
         }
 
@@ -557,7 +557,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for Generalizer<'_, 'tcx> {
             _ => relate::structurally_relate_tys(self, t, t),
         }?;
 
-        self.cache.insert(t, g);
+        self.cache.insert((t, self.ambient_variance, self.in_alias), g);
         Ok(g)
     }
 

compiler/rustc_lint/src/expect.rs

@@ -1,10 +1,10 @@
-use rustc_data_structures::fx::FxIndexMap;
-use rustc_hir::{HirId, CRATE_OWNER_ID};
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::CRATE_OWNER_ID;
 use rustc_middle::lint::LintExpectation;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint::builtin::UNFULFILLED_LINT_EXPECTATIONS;
-use rustc_session::lint::{Level, LintExpectationId};
+use rustc_session::lint::LintExpectationId;
 use rustc_span::Symbol;
 
 use crate::lints::{Expectation, ExpectationNote};
@@ -17,43 +17,12 @@ fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(LintExpectationId, LintExp
     let krate = tcx.hir_crate_items(());
 
     let mut expectations = Vec::new();
-    let mut unstable_to_stable_ids = FxIndexMap::default();
 
-    let mut record_stable = |attr_id, hir_id, attr_index| {
-        let expect_id = LintExpectationId::Stable { hir_id, attr_index, lint_index: None };
-        unstable_to_stable_ids.entry(attr_id).or_insert(expect_id);
-    };
-    let mut push_expectations = |owner| {
+    for owner in std::iter::once(CRATE_OWNER_ID).chain(krate.owners()) {
         let lints = tcx.shallow_lint_levels_on(owner);
-        if lints.expectations.is_empty() {
-            return;
-        }
-
         expectations.extend_from_slice(&lints.expectations);
-
-        let attrs = tcx.hir_attrs(owner);
-        for &(local_id, attrs) in attrs.map.iter() {
-            // Some attributes appear multiple times in HIR, to ensure they are correctly taken
-            // into account where they matter. This means we cannot just associate the AttrId to
-            // the first HirId where we see it, but need to check it actually appears in a lint
-            // level.
-            // FIXME(cjgillot): Can this cause an attribute to appear in multiple expectation ids?
-            if !lints.specs.contains_key(&local_id) {
-                continue;
-            }
-            for (attr_index, attr) in attrs.iter().enumerate() {
-                let Some(Level::Expect(_)) = Level::from_attr(attr) else { continue };
-                record_stable(attr.id, HirId { owner, local_id }, attr_index.try_into().unwrap());
-            }
-        }
-    };
-
-    push_expectations(CRATE_OWNER_ID);
-    for owner in krate.owners() {
-        push_expectations(owner);
     }
 
-    tcx.dcx().update_unstable_expectation_id(unstable_to_stable_ids);
     expectations
 }
 
@@ -61,24 +30,43 @@ fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
     let lint_expectations = tcx.lint_expectations(());
     let fulfilled_expectations = tcx.dcx().steal_fulfilled_expectation_ids();
 
-    for (id, expectation) in lint_expectations {
-        // This check will always be true, since `lint_expectations` only
-        // holds stable ids
-        if let LintExpectationId::Stable { hir_id, .. } = id {
-            if !fulfilled_expectations.contains(id)
-                && tool_filter.map_or(true, |filter| expectation.lint_tool == Some(filter))
-            {
-                let rationale = expectation.reason.map(|rationale| ExpectationNote { rationale });
-                let note = expectation.is_unfulfilled_lint_expectations;
-                tcx.emit_node_span_lint(
-                    UNFULFILLED_LINT_EXPECTATIONS,
-                    *hir_id,
-                    expectation.emission_span,
-                    Expectation { rationale, note },
-                );
+    // Turn a `LintExpectationId` into a `(AttrId, lint_index)` pair.
+    let canonicalize_id = |expect_id: &LintExpectationId| {
+        match *expect_id {
+            LintExpectationId::Unstable { attr_id, lint_index: Some(lint_index) } => {
+                (attr_id, lint_index)
             }
-        } else {
+            LintExpectationId::Stable { hir_id, attr_index, lint_index: Some(lint_index) } => {
+                // We are an `eval_always` query, so looking at the attribute's `AttrId` is ok.
+                let attr_id = tcx.hir().attrs(hir_id)[attr_index as usize].id;
+                (attr_id, lint_index)
+            }
+            _ => panic!("fulfilled expectations must have a lint index"),
+        }
+    };
+
+    let fulfilled_expectations: FxHashSet<_> =
+        fulfilled_expectations.iter().map(canonicalize_id).collect();
+
+    for (expect_id, expectation) in lint_expectations {
+        // This check will always be true, since `lint_expectations` only holds stable ids
+        let LintExpectationId::Stable { hir_id, .. } = expect_id else {
             unreachable!("at this stage all `LintExpectationId`s are stable");
+        };
+
+        let expect_id = canonicalize_id(expect_id);
+
+        if !fulfilled_expectations.contains(&expect_id)
+            && tool_filter.map_or(true, |filter| expectation.lint_tool == Some(filter))
+        {
+            let rationale = expectation.reason.map(|rationale| ExpectationNote { rationale });
+            let note = expectation.is_unfulfilled_lint_expectations;
+            tcx.emit_node_span_lint(
+                UNFULFILLED_LINT_EXPECTATIONS,
+                *hir_id,
+                expectation.emission_span,
+                Expectation { rationale, note },
+            );
         }
     }
 }

compiler/rustc_lint/src/for_loops_over_fallibles.rs

@@ -133,7 +133,7 @@ fn extract_iterator_next_call<'tcx>(
     {
         Some(recv)
     } else {
-        return None;
+        None
     }
 }
 

compiler/rustc_middle/src/hir/map/mod.rs

@@ -71,7 +71,7 @@ impl<'hir> Iterator for ParentHirIterator<'hir> {
         debug_assert_ne!(parent_id, self.current_id);
 
         self.current_id = parent_id;
-        return Some(parent_id);
+        Some(parent_id)
     }
 }
 
@@ -103,7 +103,7 @@ impl<'hir> Iterator for ParentOwnerIterator<'hir> {
         self.current_id = HirId::make_owner(parent_id.def_id);
 
         let node = self.map.tcx.hir_owner_node(self.current_id.owner);
-        return Some((self.current_id.owner, node));
+        Some((self.current_id.owner, node))
     }
 }
 
@@ -1233,14 +1233,14 @@ pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> Mod
         body_owners,
         ..
     } = collector;
-    return ModuleItems {
+    ModuleItems {
         submodules: submodules.into_boxed_slice(),
         free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
         body_owners: body_owners.into_boxed_slice(),
-    };
+    }
 }
 
 pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
@@ -1262,14 +1262,14 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
         ..
     } = collector;
 
-    return ModuleItems {
+    ModuleItems {
         submodules: submodules.into_boxed_slice(),
         free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
         body_owners: body_owners.into_boxed_slice(),
-    };
+    }
 }
 
 struct ItemCollector<'tcx> {

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -641,7 +641,7 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
     pub fn write_uninit(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult {
         self.mark_init(range, false);
         self.provenance.clear(range, cx)?;
-        return Ok(());
+        Ok(())
     }
 
     /// Remove all provenance in the given memory range.

compiler/rustc_middle/src/mir/mod.rs

@@ -1166,10 +1166,9 @@ impl<'tcx> LocalDecl<'tcx> {
     /// Returns `true` if this is a DerefTemp
     pub fn is_deref_temp(&self) -> bool {
         match self.local_info() {
-            LocalInfo::DerefTemp => return true,
-            _ => (),
+            LocalInfo::DerefTemp => true,
+            _ => false,
         }
-        return false;
     }
 
     /// Returns `true` is the local is from a compiler desugaring, e.g.,

compiler/rustc_middle/src/ty/context.rs

@@ -2007,7 +2007,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 ));
             }
         }
-        return None;
+        None
     }
 
     /// Checks if the bound region is in Impl Item.

compiler/rustc_middle/src/ty/region.rs

@@ -431,7 +431,7 @@ impl BoundRegionKind {
 
     pub fn get_id(&self) -> Option<DefId> {
         match *self {
-            BoundRegionKind::BrNamed(id, _) => return Some(id),
+            BoundRegionKind::BrNamed(id, _) => Some(id),
             _ => None,
         }
     }

compiler/rustc_mir_build/src/build/custom/parse.rs

@@ -82,13 +82,11 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
     fn statement_as_expr(&self, stmt_id: StmtId) -> PResult<ExprId> {
         match &self.thir[stmt_id].kind {
             StmtKind::Expr { expr, .. } => Ok(*expr),
-            kind @ StmtKind::Let { pattern, .. } => {
-                return Err(ParseError {
-                    span: pattern.span,
-                    item_description: format!("{kind:?}"),
-                    expected: "expression".to_string(),
-                });
-            }
+            kind @ StmtKind::Let { pattern, .. } => Err(ParseError {
+                span: pattern.span,
+                item_description: format!("{kind:?}"),
+                expected: "expression".to_string(),
+            }),
         }
     }
 

compiler/rustc_monomorphize/src/collector.rs

@@ -1193,7 +1193,7 @@ fn assoc_fn_of_type<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, fn_ident: Ident) ->
             return Some(new.def_id);
         }
     }
-    return None;
+    None
 }
 
 /// Scans the MIR in order to find function calls, closures, and drop-glue.

compiler/rustc_parse/src/lexer/tokentrees.rs

@@ -299,7 +299,7 @@ impl<'psess, 'src> TokenTreesReader<'psess, 'src> {
             }
             return diff_errs;
         }
-        return errs;
+        errs
     }
 
     fn close_delim_err(&mut self, delim: Delimiter) -> PErr<'psess> {

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -2553,7 +2553,7 @@ impl<'a> Parser<'a> {
                 err.delay_as_bug();
             }
         }
-        return Ok(false); // Don't continue.
+        Ok(false) // Don't continue.
     }
 
     /// Attempt to parse a generic const argument that has not been enclosed in braces.

compiler/rustc_parse/src/parser/item.rs

@@ -457,7 +457,7 @@ impl<'a> Parser<'a> {
 
     fn parse_item_builtin(&mut self) -> PResult<'a, Option<ItemInfo>> {
         // To be expanded
-        return Ok(None);
+        Ok(None)
     }
 
     /// Parses an item macro, e.g., `item!();`.

compiler/rustc_passes/messages.ftl

@@ -484,6 +484,9 @@ passes_must_not_suspend =
 passes_must_use_no_effect =
     `#[must_use]` has no effect when applied to {$article} {$target}
 
+passes_naked_asm_outside_naked_fn =
+    the `naked_asm!` macro can only be used in functions marked with `#[naked]`
+
 passes_naked_functions_asm_block =
     naked functions must contain a single asm block
     .label_multiple_asm = multiple asm blocks are unsupported in naked functions

compiler/rustc_passes/src/check_attr.rs

@@ -1905,10 +1905,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             || (int_reprs == 1
                 && is_c
                 && item.is_some_and(|item| {
-                    if let ItemLike::Item(item) = item {
-                        return is_c_like_enum(item);
-                    }
-                    return false;
+                    if let ItemLike::Item(item) = item { is_c_like_enum(item) } else { false }
                 }))
         {
             self.tcx.emit_node_span_lint(

compiler/rustc_passes/src/dead.rs

@@ -394,7 +394,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
             }
         }
 
-        return false;
+        false
     }
 
     fn visit_node(&mut self, node: Node<'tcx>) {

compiler/rustc_passes/src/errors.rs

@@ -1221,6 +1221,13 @@ pub(crate) struct NakedFunctionIncompatibleAttribute {
     pub attr: Symbol,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_naked_asm_outside_naked_fn)]
+pub(crate) struct NakedAsmOutsideNakedFn {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_attr_only_in_functions)]
 pub(crate) struct AttrOnlyInFunctions {

compiler/rustc_passes/src/naked_functions.rs

@@ -6,6 +6,7 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::{ExprKind, HirIdSet, InlineAsmOperand, StmtKind};
+use rustc_middle::hir::nested_filter::OnlyBodies;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint::builtin::UNDEFINED_NAKED_FUNCTION_ABI;
@@ -14,8 +15,9 @@ use rustc_span::Span;
 use rustc_target::spec::abi::Abi;
 
 use crate::errors::{
-    NakedFunctionsAsmBlock, NakedFunctionsAsmOptions, NakedFunctionsMustUseNoreturn,
-    NakedFunctionsOperands, NoPatterns, ParamsNotAllowed, UndefinedNakedFunctionAbi,
+    NakedAsmOutsideNakedFn, NakedFunctionsAsmBlock, NakedFunctionsAsmOptions,
+    NakedFunctionsMustUseNoreturn, NakedFunctionsOperands, NoPatterns, ParamsNotAllowed,
+    UndefinedNakedFunctionAbi,
 };
 
 pub(crate) fn provide(providers: &mut Providers) {
@@ -29,11 +31,6 @@ fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
             continue;
         }
 
-        let naked = tcx.has_attr(def_id, sym::naked);
-        if !naked {
-            continue;
-        }
-
         let (fn_header, body_id) = match tcx.hir_node_by_def_id(def_id) {
             hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. })
             | hir::Node::TraitItem(hir::TraitItem {
@@ -48,10 +45,17 @@ fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
         };
 
         let body = tcx.hir().body(body_id);
-        check_abi(tcx, def_id, fn_header.abi);
-        check_no_patterns(tcx, body.params);
-        check_no_parameters_use(tcx, body);
-        check_asm(tcx, def_id, body);
+
+        if tcx.has_attr(def_id, sym::naked) {
+            check_abi(tcx, def_id, fn_header.abi);
+            check_no_patterns(tcx, body.params);
+            check_no_parameters_use(tcx, body);
+            check_asm(tcx, def_id, body);
+        } else {
+            // `naked_asm!` is not allowed outside of functions marked as `#[naked]`
+            let mut visitor = CheckNakedAsmInNakedFn { tcx };
+            visitor.visit_body(body);
+        }
     }
 }
 
@@ -276,3 +280,25 @@ impl<'tcx> Visitor<'tcx> for CheckInlineAssembly<'tcx> {
         self.check_expr(expr, expr.span);
     }
 }
+
+struct CheckNakedAsmInNakedFn<'tcx> {
+    tcx: TyCtxt<'tcx>,
+}
+
+impl<'tcx> Visitor<'tcx> for CheckNakedAsmInNakedFn<'tcx> {
+    type NestedFilter = OnlyBodies;
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        self.tcx.hir()
+    }
+
+    fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
+        if let ExprKind::InlineAsm(inline_asm) = expr.kind {
+            if let rustc_ast::AsmMacro::NakedAsm = inline_asm.asm_macro {
+                self.tcx.dcx().emit_err(NakedAsmOutsideNakedFn { span: expr.span });
+            }
+        }
+
+        hir::intravisit::walk_expr(self, expr);
+    }
+}

compiler/rustc_pattern_analysis/src/usefulness.rs

@@ -951,7 +951,11 @@ impl<Cx: PatCx> PlaceInfo<Cx> {
             self.is_scrutinee && matches!(ctors_for_ty, ConstructorSet::NoConstructors);
         // Whether empty patterns are counted as useful or not. We only warn an empty arm unreachable if
         // it is guaranteed unreachable by the opsem (i.e. if the place is `known_valid`).
-        let empty_arms_are_unreachable = self.validity.is_known_valid();
+        // We don't want to warn empty patterns as unreachable by default just yet. We will in a
+        // later version of rust or under a different lint name, see
+        // https://github.com/rust-lang/rust/pull/129103.
+        let empty_arms_are_unreachable = self.validity.is_known_valid()
+            && (is_toplevel_exception || cx.is_exhaustive_patterns_feature_on());
         // Whether empty patterns can be omitted for exhaustiveness. We ignore place validity in the
         // toplevel exception and `exhaustive_patterns` cases for backwards compatibility.
         let can_omit_empty_arms = self.validity.is_known_valid()

compiler/rustc_resolve/src/diagnostics.rs

@@ -3076,7 +3076,7 @@ fn search_for_any_use_in_items(items: &[P<ast::Item>]) -> Option<Span> {
             }
         }
     }
-    return None;
+    None
 }
 
 fn is_span_suitable_for_use_injection(s: Span) -> bool {

compiler/rustc_resolve/src/late.rs

@@ -5016,5 +5016,5 @@ fn def_id_matches_path(tcx: TyCtxt<'_>, mut def_id: DefId, expected_path: &[&str
         }
         def_id = parent;
     }
-    return true;
+    true
 }

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -779,7 +779,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
             candidates = self.smart_resolve_partial_mod_path_errors(path, following_seg);
         }
 
-        return (false, candidates);
+        (false, candidates)
     }
 
     fn suggest_trait_and_bounds(

compiler/rustc_session/src/filesearch.rs

@@ -182,7 +182,7 @@ pub fn sysroot_candidates() -> SmallVec<[PathBuf; 2]> {
         }
     }
 
-    return sysroot_candidates;
+    sysroot_candidates
 }
 
 /// Returns the provided sysroot or calls [`get_or_default_sysroot`] if it's none.

compiler/rustc_session/src/options.rs

@@ -353,7 +353,7 @@ fn build_options<O: Default>(
             None => early_dcx.early_fatal(format!("unknown {outputname} option: `{key}`")),
         }
     }
-    return op;
+    op
 }
 
 #[allow(non_upper_case_globals)]

compiler/rustc_session/src/search_paths.rs

@@ -96,7 +96,7 @@ impl SearchPath {
         Self::new(PathKind::All, make_target_lib_path(sysroot, triple))
     }
 
-    fn new(kind: PathKind, dir: PathBuf) -> Self {
+    pub fn new(kind: PathKind, dir: PathBuf) -> Self {
         // Get the files within the directory.
         let files = match std::fs::read_dir(&dir) {
             Ok(files) => files

compiler/rustc_span/src/source_map.rs

@@ -779,7 +779,7 @@ impl SourceMap {
                     return Ok(false);
                 }
             }
-            return Ok(true);
+            Ok(true)
         })
         .is_ok_and(|is_accessible| is_accessible)
     }

compiler/rustc_span/src/symbol.rs

@@ -1236,7 +1236,6 @@ symbols! {
         mir_unwind_unreachable,
         mir_variant,
         miri,
-        missing_docs,
         mmx_reg,
         modifiers,
         module,

compiler/rustc_target/src/abi/call/mod.rs

@@ -188,7 +188,7 @@ impl ArgAttributes {
         if self.arg_ext != other.arg_ext {
             return false;
         }
-        return true;
+        true
     }
 }
 
@@ -632,7 +632,7 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
             PassMode::Indirect { .. } => {
                 self.mode = PassMode::Direct(ArgAttributes::new());
             }
-            PassMode::Ignore | PassMode::Direct(_) | PassMode::Pair(_, _) => return, // already direct
+            PassMode::Ignore | PassMode::Direct(_) | PassMode::Pair(_, _) => {} // already direct
             _ => panic!("Tried to make {:?} direct", self.mode),
         }
     }
@@ -646,7 +646,6 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
             }
             PassMode::Indirect { attrs: _, meta_attrs: _, on_stack: false } => {
                 // already indirect
-                return;
             }
             _ => panic!("Tried to make {:?} indirect", self.mode),
         }
@@ -661,7 +660,6 @@ impl<'a, Ty> ArgAbi<'a, Ty> {
             }
             PassMode::Indirect { attrs: _, meta_attrs: _, on_stack: false } => {
                 // already indirect
-                return;
             }
             _ => panic!("Tried to make {:?} indirect (expected `PassMode::Ignore`)", self.mode),
         }

compiler/rustc_target/src/abi/call/sparc64.rs

@@ -66,7 +66,7 @@ where
         data.last_offset = offset + Reg::f64().size;
     }
     data.prefix_index += 1;
-    return data;
+    data
 }
 
 fn arg_scalar_pair<C>(
@@ -92,7 +92,7 @@ where
         offset += Size::from_bytes(4 - (offset.bytes() % 4));
     }
     data = arg_scalar(cx, scalar2, offset, data);
-    return data;
+    data
 }
 
 fn parse_structure<'a, Ty, C>(
@@ -128,7 +128,7 @@ where
         }
     }
 
-    return data;
+    data
 }
 
 fn classify_arg<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>, in_registers_max: Size)

library/core/src/num/f128.rs

@@ -439,10 +439,6 @@ impl f128 {
     #[unstable(feature = "f128", issue = "116909")]
     #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     pub const fn classify(self) -> FpCategory {
-        // Other float types suffer from various platform bugs that violate the usual IEEE semantics
-        // and also make bitwise classification not always work reliably. However, `f128` cannot fit
-        // into any other float types so this is not a concern, and we can rely on bit patterns.
-
         let bits = self.to_bits();
         match (bits & Self::MAN_MASK, bits & Self::EXP_MASK) {
             (0, Self::EXP_MASK) => FpCategory::Infinite,

library/core/src/num/f16.rs

@@ -424,42 +424,13 @@ impl f16 {
     #[unstable(feature = "f16", issue = "116909")]
     #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     pub const fn classify(self) -> FpCategory {
-        // A previous implementation for f32/f64 tried to only use bitmask-based checks,
-        // using `to_bits` to transmute the float to its bit repr and match on that.
-        // If we only cared about being "technically" correct, that's an entirely legit
-        // implementation.
-        //
-        // Unfortunately, there are platforms out there that do not correctly implement the IEEE
-        // float semantics Rust relies on: some hardware flushes denormals to zero, and some
-        // platforms convert to `f32` to perform operations without properly rounding back (e.g.
-        // WASM, see llvm/llvm-project#96437). These are platforms bugs, and Rust will misbehave on
-        // such platforms, but we can at least try to make things seem as sane as possible by being
-        // careful here.
-        if self.is_infinite() {
-            // Thus, a value may compare unequal to infinity, despite having a "full" exponent mask.
-            FpCategory::Infinite
-        } else if self.is_nan() {
-            // And it may not be NaN, as it can simply be an "overextended" finite value.
-            FpCategory::Nan
-        } else {
-            // However, std can't simply compare to zero to check for zero, either,
-            // as correctness requires avoiding equality tests that may be Subnormal == -0.0
-            // because it may be wrong under "denormals are zero" and "flush to zero" modes.
-            // Most of std's targets don't use those, but they are used for thumbv7neon.
-            // So, this does use bitpattern matching for the rest. On x87, due to the incorrect
-            // float codegen on this hardware, this doesn't actually return a right answer for NaN
-            // because it cannot correctly discern between a floating point NaN, and some normal
-            // floating point numbers truncated from an x87 FPU -- but we took care of NaN above, so
-            // we are fine.
-            // FIXME(jubilee): This probably could at least answer things correctly for Infinity,
-            // like the f64 version does, but I need to run more checks on how things go on x86.
-            // I fear losing mantissa data that would have answered that differently.
-            let b = self.to_bits();
-            match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
-                (0, 0) => FpCategory::Zero,
-                (_, 0) => FpCategory::Subnormal,
-                _ => FpCategory::Normal,
-            }
+        let b = self.to_bits();
+        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
+            (0, Self::EXP_MASK) => FpCategory::Infinite,
+            (_, Self::EXP_MASK) => FpCategory::Nan,
+            (0, 0) => FpCategory::Zero,
+            (_, 0) => FpCategory::Subnormal,
+            _ => FpCategory::Normal,
         }
     }
 

library/core/src/num/f32.rs

@@ -652,45 +652,18 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     pub const fn classify(self) -> FpCategory {
-        // A previous implementation tried to only use bitmask-based checks,
-        // using f32::to_bits to transmute the float to its bit repr and match on that.
-        // If we only cared about being "technically" correct, that's an entirely legit
-        // implementation.
-        //
-        // Unfortunately, there is hardware out there that does not correctly implement the IEEE
-        // float semantics Rust relies on: x87 uses a too-large mantissa and exponent, and some
-        // hardware flushes subnormals to zero. These are platforms bugs, and Rust will misbehave on
-        // such hardware, but we can at least try to make things seem as sane as possible by being
-        // careful here.
-        //
-        // FIXME(jubilee): Using x87 operations is never necessary in order to function
-        // on x86 processors for Rust-to-Rust calls, so this issue should not happen.
-        // Code generation should be adjusted to use non-C calling conventions, avoiding this.
-        if self.is_infinite() {
-            // A value may compare unequal to infinity, despite having a "full" exponent mask.
-            FpCategory::Infinite
-        } else if self.is_nan() {
-            // And it may not be NaN, as it can simply be an "overextended" finite value.
-            FpCategory::Nan
-        } else {
-            // However, std can't simply compare to zero to check for zero, either,
-            // as correctness requires avoiding equality tests that may be Subnormal == -0.0
-            // because it may be wrong under "denormals are zero" and "flush to zero" modes.
-            // Most of std's targets don't use those, but they are used for thumbv7neon.
-            // So, this does use bitpattern matching for the rest. On x87, due to the incorrect
-            // float codegen on this hardware, this doesn't actually return a right answer for NaN
-            // because it cannot correctly discern between a floating point NaN, and some normal
-            // floating point numbers truncated from an x87 FPU -- but we took care of NaN above, so
-            // we are fine.
-            // FIXME(jubilee): This probably could at least answer things correctly for Infinity,
-            // like the f64 version does, but I need to run more checks on how things go on x86.
-            // I fear losing mantissa data that would have answered that differently.
-            let b = self.to_bits();
-            match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
-                (0, 0) => FpCategory::Zero,
-                (_, 0) => FpCategory::Subnormal,
-                _ => FpCategory::Normal,
-            }
+        // We used to have complicated logic here that avoids the simple bit-based tests to work
+        // around buggy codegen for x87 targets (see
+        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
+        // of our tests is able to find any difference between the complicated and the naive
+        // version, so now we are back to the naive version.
+        let b = self.to_bits();
+        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
+            (0, Self::EXP_MASK) => FpCategory::Infinite,
+            (_, Self::EXP_MASK) => FpCategory::Nan,
+            (0, 0) => FpCategory::Zero,
+            (_, 0) => FpCategory::Subnormal,
+            _ => FpCategory::Normal,
         }
     }
 

library/core/src/num/f64.rs

@@ -651,41 +651,18 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")]
     pub const fn classify(self) -> FpCategory {
-        // A previous implementation tried to only use bitmask-based checks,
-        // using f64::to_bits to transmute the float to its bit repr and match on that.
-        // If we only cared about being "technically" correct, that's an entirely legit
-        // implementation.
-        //
-        // Unfortunately, there is hardware out there that does not correctly implement the IEEE
-        // float semantics Rust relies on: x87 uses a too-large exponent, and some hardware flushes
-        // subnormals to zero. These are platforms bugs, and Rust will misbehave on such hardware,
-        // but we can at least try to make things seem as sane as possible by being careful here.
-        //
-        // FIXME(jubilee): Using x87 operations is never necessary in order to function
-        // on x86 processors for Rust-to-Rust calls, so this issue should not happen.
-        // Code generation should be adjusted to use non-C calling conventions, avoiding this.
-        //
-        // Thus, a value may compare unequal to infinity, despite having a "full" exponent mask.
-        // And it may not be NaN, as it can simply be an "overextended" finite value.
-        if self.is_nan() {
-            FpCategory::Nan
-        } else {
-            // However, std can't simply compare to zero to check for zero, either,
-            // as correctness requires avoiding equality tests that may be Subnormal == -0.0
-            // because it may be wrong under "denormals are zero" and "flush to zero" modes.
-            // Most of std's targets don't use those, but they are used for thumbv7neon.
-            // So, this does use bitpattern matching for the rest. On x87, due to the incorrect
-            // float codegen on this hardware, this doesn't actually return a right answer for NaN
-            // because it cannot correctly discern between a floating point NaN, and some normal
-            // floating point numbers truncated from an x87 FPU -- but we took care of NaN above, so
-            // we are fine.
-            let b = self.to_bits();
-            match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
-                (0, Self::EXP_MASK) => FpCategory::Infinite,
-                (0, 0) => FpCategory::Zero,
-                (_, 0) => FpCategory::Subnormal,
-                _ => FpCategory::Normal,
-            }
+        // We used to have complicated logic here that avoids the simple bit-based tests to work
+        // around buggy codegen for x87 targets (see
+        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
+        // of our tests is able to find any difference between the complicated and the naive
+        // version, so now we are back to the naive version.
+        let b = self.to_bits();
+        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
+            (0, Self::EXP_MASK) => FpCategory::Infinite,
+            (_, Self::EXP_MASK) => FpCategory::Nan,
+            (0, 0) => FpCategory::Zero,
+            (_, 0) => FpCategory::Subnormal,
+            _ => FpCategory::Normal,
         }
     }
 

library/core/src/unicode/printable.rs

@@ -118,7 +118,7 @@ const SINGLETONS0U: &[(u8, u8)] = &[
     (0x30, 4),
     (0x31, 2),
     (0x32, 1),
-    (0xa7, 2),
+    (0xa7, 4),
     (0xa9, 2),
     (0xaa, 4),
     (0xab, 8),
@@ -155,17 +155,18 @@ const SINGLETONS0L: &[u8] = &[
     0x11, 0x16, 0x17, 0x5b, 0x5c, 0xf6, 0xf7, 0xfe,
     0xff, 0x80, 0x6d, 0x71, 0xde, 0xdf, 0x0e, 0x1f,
     0x6e, 0x6f, 0x1c, 0x1d, 0x5f, 0x7d, 0x7e, 0xae,
-    0xaf, 0x7f, 0xbb, 0xbc, 0x16, 0x17, 0x1e, 0x1f,
+    0xaf, 0x4d, 0xbb, 0xbc, 0x16, 0x17, 0x1e, 0x1f,
     0x46, 0x47, 0x4e, 0x4f, 0x58, 0x5a, 0x5c, 0x5e,
     0x7e, 0x7f, 0xb5, 0xc5, 0xd4, 0xd5, 0xdc, 0xf0,
     0xf1, 0xf5, 0x72, 0x73, 0x8f, 0x74, 0x75, 0x96,
     0x26, 0x2e, 0x2f, 0xa7, 0xaf, 0xb7, 0xbf, 0xc7,
     0xcf, 0xd7, 0xdf, 0x9a, 0x00, 0x40, 0x97, 0x98,
-    0x30, 0x8f, 0x1f, 0xd2, 0xd4, 0xce, 0xff, 0x4e,
-    0x4f, 0x5a, 0x5b, 0x07, 0x08, 0x0f, 0x10, 0x27,
-    0x2f, 0xee, 0xef, 0x6e, 0x6f, 0x37, 0x3d, 0x3f,
-    0x42, 0x45, 0x90, 0x91, 0x53, 0x67, 0x75, 0xc8,
-    0xc9, 0xd0, 0xd1, 0xd8, 0xd9, 0xe7, 0xfe, 0xff,
+    0x30, 0x8f, 0x1f, 0xce, 0xcf, 0xd2, 0xd4, 0xce,
+    0xff, 0x4e, 0x4f, 0x5a, 0x5b, 0x07, 0x08, 0x0f,
+    0x10, 0x27, 0x2f, 0xee, 0xef, 0x6e, 0x6f, 0x37,
+    0x3d, 0x3f, 0x42, 0x45, 0x90, 0x91, 0x53, 0x67,
+    0x75, 0xc8, 0xc9, 0xd0, 0xd1, 0xd8, 0xd9, 0xe7,
+    0xfe, 0xff,
 ];
 #[rustfmt::skip]
 const SINGLETONS1U: &[(u8, u8)] = &[
@@ -183,7 +184,7 @@ const SINGLETONS1U: &[(u8, u8)] = &[
     (0x10, 1),
     (0x11, 2),
     (0x12, 5),
-    (0x13, 17),
+    (0x13, 28),
     (0x14, 1),
     (0x15, 2),
     (0x17, 2),
@@ -211,7 +212,7 @@ const SINGLETONS1U: &[(u8, u8)] = &[
     (0xee, 32),
     (0xf0, 4),
     (0xf8, 2),
-    (0xfa, 3),
+    (0xfa, 4),
     (0xfb, 1),
 ];
 #[rustfmt::skip]
@@ -224,23 +225,24 @@ const SINGLETONS1L: &[u8] = &[
     0xbd, 0x35, 0xe0, 0x12, 0x87, 0x89, 0x8e, 0x9e,
     0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34,
     0x3a, 0x45, 0x46, 0x49, 0x4a, 0x4e, 0x4f, 0x64,
-    0x65, 0x5c, 0xb6, 0xb7, 0x1b, 0x1c, 0x07, 0x08,
-    0x0a, 0x0b, 0x14, 0x17, 0x36, 0x39, 0x3a, 0xa8,
-    0xa9, 0xd8, 0xd9, 0x09, 0x37, 0x90, 0x91, 0xa8,
-    0x07, 0x0a, 0x3b, 0x3e, 0x66, 0x69, 0x8f, 0x92,
-    0x11, 0x6f, 0x5f, 0xbf, 0xee, 0xef, 0x5a, 0x62,
-    0xf4, 0xfc, 0xff, 0x53, 0x54, 0x9a, 0x9b, 0x2e,
-    0x2f, 0x27, 0x28, 0x55, 0x9d, 0xa0, 0xa1, 0xa3,
-    0xa4, 0xa7, 0xa8, 0xad, 0xba, 0xbc, 0xc4, 0x06,
-    0x0b, 0x0c, 0x15, 0x1d, 0x3a, 0x3f, 0x45, 0x51,
-    0xa6, 0xa7, 0xcc, 0xcd, 0xa0, 0x07, 0x19, 0x1a,
-    0x22, 0x25, 0x3e, 0x3f, 0xe7, 0xec, 0xef, 0xff,
-    0xc5, 0xc6, 0x04, 0x20, 0x23, 0x25, 0x26, 0x28,
-    0x33, 0x38, 0x3a, 0x48, 0x4a, 0x4c, 0x50, 0x53,
-    0x55, 0x56, 0x58, 0x5a, 0x5c, 0x5e, 0x60, 0x63,
-    0x65, 0x66, 0x6b, 0x73, 0x78, 0x7d, 0x7f, 0x8a,
-    0xa4, 0xaa, 0xaf, 0xb0, 0xc0, 0xd0, 0xae, 0xaf,
-    0x6e, 0x6f, 0xbe, 0x93,
+    0x65, 0x8a, 0x8c, 0x8d, 0x8f, 0xb6, 0xc1, 0xc3,
+    0xc4, 0xc6, 0xcb, 0xd6, 0x5c, 0xb6, 0xb7, 0x1b,
+    0x1c, 0x07, 0x08, 0x0a, 0x0b, 0x14, 0x17, 0x36,
+    0x39, 0x3a, 0xa8, 0xa9, 0xd8, 0xd9, 0x09, 0x37,
+    0x90, 0x91, 0xa8, 0x07, 0x0a, 0x3b, 0x3e, 0x66,
+    0x69, 0x8f, 0x92, 0x11, 0x6f, 0x5f, 0xbf, 0xee,
+    0xef, 0x5a, 0x62, 0xf4, 0xfc, 0xff, 0x53, 0x54,
+    0x9a, 0x9b, 0x2e, 0x2f, 0x27, 0x28, 0x55, 0x9d,
+    0xa0, 0xa1, 0xa3, 0xa4, 0xa7, 0xa8, 0xad, 0xba,
+    0xbc, 0xc4, 0x06, 0x0b, 0x0c, 0x15, 0x1d, 0x3a,
+    0x3f, 0x45, 0x51, 0xa6, 0xa7, 0xcc, 0xcd, 0xa0,
+    0x07, 0x19, 0x1a, 0x22, 0x25, 0x3e, 0x3f, 0xe7,
+    0xec, 0xef, 0xff, 0xc5, 0xc6, 0x04, 0x20, 0x23,
+    0x25, 0x26, 0x28, 0x33, 0x38, 0x3a, 0x48, 0x4a,
+    0x4c, 0x50, 0x53, 0x55, 0x56, 0x58, 0x5a, 0x5c,
+    0x5e, 0x60, 0x63, 0x65, 0x66, 0x6b, 0x73, 0x78,
+    0x7d, 0x7f, 0x8a, 0xa4, 0xaa, 0xaf, 0xb0, 0xc0,
+    0xd0, 0xae, 0xaf, 0x6e, 0x6f, 0xdd, 0xde, 0x93,
 ];
 #[rustfmt::skip]
 const NORMAL0: &[u8] = &[
@@ -252,8 +254,8 @@ const NORMAL0: &[u8] = &[
     0x06, 0x11,
     0x81, 0xac, 0x0e,
     0x80, 0xab, 0x05,
-    0x1f, 0x09,
-    0x81, 0x1b, 0x03,
+    0x1f, 0x08,
+    0x81, 0x1c, 0x03,
     0x19, 0x08,
     0x01, 0x04,
     0x2f, 0x04,
@@ -318,11 +320,10 @@ const NORMAL0: &[u8] = &[
     0x80, 0xac, 0x06,
     0x0a, 0x06,
     0x2f, 0x31,
-    0x4d, 0x03,
-    0x80, 0xa4, 0x08,
+    0x80, 0xf4, 0x08,
     0x3c, 0x03,
     0x0f, 0x03,
-    0x3c, 0x07,
+    0x3e, 0x05,
     0x38, 0x08,
     0x2b, 0x05,
     0x82, 0xff, 0x11,
@@ -332,7 +333,7 @@ const NORMAL0: &[u8] = &[
     0x21, 0x0f,
     0x21, 0x0f,
     0x80, 0x8c, 0x04,
-    0x82, 0x97, 0x19,
+    0x82, 0x9a, 0x16,
     0x0b, 0x15,
     0x88, 0x94, 0x05,
     0x2f, 0x05,
@@ -343,13 +344,12 @@ const NORMAL0: &[u8] = &[
     0x74, 0x0c,
     0x80, 0xd6, 0x1a,
     0x81, 0x10, 0x05,
-    0x80, 0xdf, 0x0b,
+    0x80, 0xe1, 0x09,
     0xf2, 0x9e, 0x03,
     0x37, 0x09,
     0x81, 0x5c, 0x14,
     0x80, 0xb8, 0x08,
-    0x80, 0xcb, 0x05,
-    0x0a, 0x18,
+    0x80, 0xdd, 0x15,
     0x3b, 0x03,
     0x0a, 0x06,
     0x38, 0x08,
@@ -402,7 +402,8 @@ const NORMAL1: &[u8] = &[
     0x24, 0x04,
     0x28, 0x08,
     0x34, 0x0b,
-    0x4e, 0x43,
+    0x4e, 0x03,
+    0x34, 0x0c,
     0x81, 0x37, 0x09,
     0x16, 0x0a,
     0x08, 0x18,
@@ -431,9 +432,13 @@ const NORMAL1: &[u8] = &[
     0x33, 0x0d,
     0x33, 0x07,
     0x2e, 0x08,
-    0x0a, 0x81, 0x26,
-    0x52, 0x4b,
-    0x2b, 0x08,
+    0x0a, 0x06,
+    0x26, 0x03,
+    0x1d, 0x08,
+    0x02, 0x80, 0xd0,
+    0x52, 0x10,
+    0x03, 0x37,
+    0x2c, 0x08,
     0x2a, 0x16,
     0x1a, 0x26,
     0x1c, 0x14,
@@ -453,7 +458,9 @@ const NORMAL1: &[u8] = &[
     0x51, 0x06,
     0x01, 0x05,
     0x10, 0x03,
-    0x05, 0x80, 0x8b,
+    0x05, 0x0b,
+    0x59, 0x08,
+    0x02, 0x1d,
     0x62, 0x1e,
     0x48, 0x08,
     0x0a, 0x80, 0xa6,
@@ -462,7 +469,8 @@ const NORMAL1: &[u8] = &[
     0x0a, 0x06,
     0x0d, 0x13,
     0x3a, 0x06,
-    0x0a, 0x36,
+    0x0a, 0x06,
+    0x14, 0x1c,
     0x2c, 0x04,
     0x17, 0x80, 0xb9,
     0x3c, 0x64,
@@ -473,7 +481,9 @@ const NORMAL1: &[u8] = &[
     0x48, 0x08,
     0x53, 0x0d,
     0x49, 0x07,
-    0x0a, 0x80, 0xf6,
+    0x0a, 0x80, 0xb6,
+    0x22, 0x0e,
+    0x0a, 0x06,
     0x46, 0x0a,
     0x1d, 0x03,
     0x47, 0x49,
@@ -484,7 +494,7 @@ const NORMAL1: &[u8] = &[
     0x0a, 0x81, 0x36,
     0x19, 0x07,
     0x3b, 0x03,
-    0x1c, 0x56,
+    0x1d, 0x55,
     0x01, 0x0f,
     0x32, 0x0d,
     0x83, 0x9b, 0x66,
@@ -492,15 +502,18 @@ const NORMAL1: &[u8] = &[
     0x80, 0xc4, 0x8a, 0x4c,
     0x63, 0x0d,
     0x84, 0x30, 0x10,
-    0x16, 0x8f, 0xaa,
-    0x82, 0x47, 0xa1, 0xb9,
+    0x16, 0x0a,
+    0x8f, 0x9b, 0x05,
+    0x82, 0x47, 0x9a, 0xb9,
+    0x3a, 0x86, 0xc6,
     0x82, 0x39, 0x07,
     0x2a, 0x04,
     0x5c, 0x06,
     0x26, 0x0a,
     0x46, 0x0a,
     0x28, 0x05,
-    0x13, 0x82, 0xb0,
+    0x13, 0x81, 0xb0,
+    0x3a, 0x80, 0xc6,
     0x5b, 0x65,
     0x4b, 0x04,
     0x39, 0x07,
@@ -508,8 +521,8 @@ const NORMAL1: &[u8] = &[
     0x05, 0x0b,
     0x02, 0x0e,
     0x97, 0xf8, 0x08,
-    0x84, 0xd6, 0x2a,
-    0x09, 0xa2, 0xe7,
+    0x84, 0xd6, 0x29,
+    0x0a, 0xa2, 0xe7,
     0x81, 0x33, 0x0f,
     0x01, 0x1d,
     0x06, 0x0e,
@@ -518,7 +531,9 @@ const NORMAL1: &[u8] = &[
     0x6b, 0x05,
     0x0d, 0x03,
     0x09, 0x07,
-    0x10, 0x92, 0x60,
+    0x10, 0x8f, 0x60,
+    0x80, 0xfa, 0x06,
+    0x81, 0xb4, 0x4c,
     0x47, 0x09,
     0x74, 0x3c,
     0x80, 0xf6, 0x0a,
@@ -543,7 +558,9 @@ const NORMAL1: &[u8] = &[
     0x1f, 0x11,
     0x3a, 0x05,
     0x01, 0x81, 0xd0,
-    0x2a, 0x82, 0xe6,
+    0x2a, 0x80, 0xd6,
+    0x2b, 0x04,
+    0x01, 0x81, 0xe0,
     0x80, 0xf7, 0x29,
     0x4c, 0x04,
     0x0a, 0x04,
@@ -575,14 +592,13 @@ const NORMAL1: &[u8] = &[
     0x38, 0x08,
     0x0a, 0x06,
     0x28, 0x08,
-    0x22, 0x4e,
+    0x2c, 0x04,
+    0x02, 0x3e,
     0x81, 0x54, 0x0c,
     0x1d, 0x03,
+    0x0a, 0x05,
+    0x38, 0x07,
+    0x1c, 0x06,
     0x09, 0x07,
-    0x36, 0x08,
-    0x0e, 0x04,
-    0x09, 0x07,
-    0x09, 0x07,
-    0x80, 0xcb, 0x25,
-    0x0a, 0x84, 0x06,
+    0x80, 0xfa, 0x84, 0x06,
 ];

library/std/src/collections/mod.rs

@@ -79,42 +79,50 @@
 //! see each type's documentation, and note that the names of actual methods may
 //! differ from the tables below on certain collections.
 //!
-//! Throughout the documentation, we will follow a few conventions. For all
-//! operations, the collection's size is denoted by n. If another collection is
-//! involved in the operation, it contains m elements. Operations which have an
-//! *amortized* cost are suffixed with a `*`. Operations with an *expected*
-//! cost are suffixed with a `~`.
+//! Throughout the documentation, we will adhere to the following conventions
+//! for operation notation:
 //!
-//! All amortized costs are for the potential need to resize when capacity is
-//! exhausted. If a resize occurs it will take *O*(*n*) time. Our collections never
-//! automatically shrink, so removal operations aren't amortized. Over a
-//! sufficiently large series of operations, the average cost per operation will
-//! deterministically equal the given cost.
+//! * The collection's size is denoted by `n`.
+//! * If a second collection is involved, its size is denoted by `m`.
+//! * Item indices are denoted by `i`.
+//! * Operations which have an *amortized* cost are suffixed with a `*`.
+//! * Operations with an *expected* cost are suffixed with a `~`.
 //!
-//! Only [`HashMap`] has expected costs, due to the probabilistic nature of hashing.
-//! It is theoretically possible, though very unlikely, for [`HashMap`] to
-//! experience worse performance.
+//! Calling operations that add to a collection will occasionally require a
+//! collection to be resized - an extra operation that takes *O*(*n*) time.
 //!
-//! ## Sequences
+//! *Amortized* costs are calculated to account for the time cost of such resize
+//! operations *over a sufficiently large series of operations*. An individual
+//! operation may be slower or faster due to the sporadic nature of collection
+//! resizing, however the average cost per operation will approach the amortized
+//! cost.
 //!
-//! |                | get(i)                 | insert(i)               | remove(i)              | append    | split_off(i)           |
-//! |----------------|------------------------|-------------------------|------------------------|-----------|------------------------|
-//! | [`Vec`]        | *O*(1)                 | *O*(*n*-*i*)*           | *O*(*n*-*i*)           | *O*(*m*)* | *O*(*n*-*i*)           |
-//! | [`VecDeque`]   | *O*(1)                 | *O*(min(*i*, *n*-*i*))* | *O*(min(*i*, *n*-*i*)) | *O*(*m*)* | *O*(min(*i*, *n*-*i*)) |
-//! | [`LinkedList`] | *O*(min(*i*, *n*-*i*)) | *O*(min(*i*, *n*-*i*))  | *O*(min(*i*, *n*-*i*)) | *O*(1)    | *O*(min(*i*, *n*-*i*)) |
+//! Rust's collections never automatically shrink, so removal operations aren't
+//! amortized.
 //!
-//! Note that where ties occur, [`Vec`] is generally going to be faster than [`VecDeque`], and
-//! [`VecDeque`] is generally going to be faster than [`LinkedList`].
+//! [`HashMap`] uses *expected* costs. It is theoretically possible, though very
+//! unlikely, for [`HashMap`] to experience significantly worse performance than
+//! the expected cost. This is due to the probabilistic nature of hashing - i.e.
+//! it is possible to generate a duplicate hash given some input key that will
+//! requires extra computation to correct.
 //!
-//! ## Maps
+//! ## Cost of Collection Operations
+//!
+//!
+//! |                | get(i)                 | insert(i)               | remove(i)              | append(Vec(m))    | split_off(i)           | range           | append       |
+//! |----------------|------------------------|-------------------------|------------------------|-------------------|------------------------|-----------------|--------------|
+//! | [`Vec`]        | *O*(1)                 | *O*(*n*-*i*)*           | *O*(*n*-*i*)           | *O*(*m*)*         | *O*(*n*-*i*)           | N/A             | N/A          |
+//! | [`VecDeque`]   | *O*(1)                 | *O*(min(*i*, *n*-*i*))* | *O*(min(*i*, *n*-*i*)) | *O*(*m*)*         | *O*(min(*i*, *n*-*i*)) | N/A             | N/A          |
+//! | [`LinkedList`] | *O*(min(*i*, *n*-*i*)) | *O*(min(*i*, *n*-*i*))  | *O*(min(*i*, *n*-*i*)) | *O*(1)            | *O*(min(*i*, *n*-*i*)) | N/A             | N/A          |
+//! | [`HashMap`]    | *O*(1)~                | *O*(1)~*                | *O*(1)~                | N/A               | N/A                    | N/A             | N/A          |
+//! | [`BTreeMap`]   | *O*(log(*n*))          | *O*(log(*n*))           | *O*(log(*n*))          | N/A               | N/A                    | *O*(log(*n*))   | *O*(*n*+*m*) |
+//!
+//! Note that where ties occur, [`Vec`] is generally going to be faster than
+//! [`VecDeque`], and [`VecDeque`] is generally going to be faster than
+//! [`LinkedList`].
 //!
 //! For Sets, all operations have the cost of the equivalent Map operation.
 //!
-//! |              | get           | insert        | remove        | range         | append       |
-//! |--------------|---------------|---------------|---------------|---------------|--------------|
-//! | [`HashMap`]  | *O*(1)~       | *O*(1)~*      | *O*(1)~       | N/A           | N/A          |
-//! | [`BTreeMap`] | *O*(log(*n*)) | *O*(log(*n*)) | *O*(log(*n*)) | *O*(log(*n*)) | *O*(*n*+*m*) |
-//!
 //! # Correct and Efficient Usage of Collections
 //!
 //! Of course, knowing which collection is the right one for the job doesn't

library/std/src/f32/tests.rs

@@ -2,31 +2,24 @@ use crate::f32::consts;
 use crate::num::{FpCategory as Fp, *};
 
 /// Smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_BITS: u32 = 0x1;
 
 /// Next smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_UP_BITS: u32 = 0x2;
 
 /// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0
-#[allow(dead_code)] // unused on x86
 const MAX_DOWN_BITS: u32 = 0x7f7f_fffe;
 
 /// Zeroed exponent, full significant
-#[allow(dead_code)] // unused on x86
 const LARGEST_SUBNORMAL_BITS: u32 = 0x007f_ffff;
 
 /// Exponent = 0b1, zeroed significand
-#[allow(dead_code)] // unused on x86
 const SMALLEST_NORMAL_BITS: u32 = 0x0080_0000;
 
 /// First pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK1: u32 = 0x002a_aaaa;
 
 /// Second pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK2: u32 = 0x0055_5555;
 
 #[allow(unused_macros)]
@@ -353,9 +346,6 @@ fn test_is_sign_negative() {
     assert!((-f32::NAN).is_sign_negative());
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_up() {
     let tiny = f32::from_bits(TINY_BITS);
@@ -386,9 +376,6 @@ fn test_next_up() {
     assert_f32_biteq!(nan2.next_up(), nan2);
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_down() {
     let tiny = f32::from_bits(TINY_BITS);

library/std/src/f64/tests.rs

@@ -2,31 +2,24 @@ use crate::f64::consts;
 use crate::num::{FpCategory as Fp, *};
 
 /// Smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_BITS: u64 = 0x1;
 
 /// Next smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_UP_BITS: u64 = 0x2;
 
 /// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0
-#[allow(dead_code)] // unused on x86
 const MAX_DOWN_BITS: u64 = 0x7fef_ffff_ffff_fffe;
 
 /// Zeroed exponent, full significant
-#[allow(dead_code)] // unused on x86
 const LARGEST_SUBNORMAL_BITS: u64 = 0x000f_ffff_ffff_ffff;
 
 /// Exponent = 0b1, zeroed significand
-#[allow(dead_code)] // unused on x86
 const SMALLEST_NORMAL_BITS: u64 = 0x0010_0000_0000_0000;
 
 /// First pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK1: u64 = 0x000a_aaaa_aaaa_aaaa;
 
 /// Second pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK2: u64 = 0x0005_5555_5555_5555;
 
 #[allow(unused_macros)]
@@ -343,9 +336,6 @@ fn test_is_sign_negative() {
     assert!((-f64::NAN).is_sign_negative());
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_up() {
     let tiny = f64::from_bits(TINY_BITS);
@@ -375,9 +365,6 @@ fn test_next_up() {
     assert_f64_biteq!(nan2.next_up(), nan2);
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_down() {
     let tiny = f64::from_bits(TINY_BITS);

library/std/src/os/windows/fs.rs

@@ -298,7 +298,7 @@ impl OpenOptionsExt for OpenOptions {
 /// of the [`BY_HANDLE_FILE_INFORMATION`] structure.
 ///
 /// [`BY_HANDLE_FILE_INFORMATION`]:
-///     https://docs.microsoft.com/en-us/windows/win32/api/fileapi/ns-fileapi-by_handle_file_information
+///     https://docs.microsoft.com/windows/win32/api/fileapi/ns-fileapi-by_handle_file_information
 #[stable(feature = "metadata_ext", since = "1.1.0")]
 pub trait MetadataExt {
     /// Returns the value of the `dwFileAttributes` field of this metadata.
@@ -322,7 +322,7 @@ pub trait MetadataExt {
     /// ```
     ///
     /// [File Attribute Constants]:
-    ///     https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants
+    ///     https://docs.microsoft.com/windows/win32/fileio/file-attribute-constants
     #[stable(feature = "metadata_ext", since = "1.1.0")]
     fn file_attributes(&self) -> u32;
 
@@ -351,7 +351,7 @@ pub trait MetadataExt {
     /// }
     /// ```
     ///
-    /// [`FILETIME`]: https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
+    /// [`FILETIME`]: https://docs.microsoft.com/windows/win32/api/minwinbase/ns-minwinbase-filetime
     #[stable(feature = "metadata_ext", since = "1.1.0")]
     fn creation_time(&self) -> u64;
 
@@ -386,7 +386,7 @@ pub trait MetadataExt {
     /// }
     /// ```
     ///
-    /// [`FILETIME`]: https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
+    /// [`FILETIME`]: https://docs.microsoft.com/windows/win32/api/minwinbase/ns-minwinbase-filetime
     #[stable(feature = "metadata_ext", since = "1.1.0")]
     fn last_access_time(&self) -> u64;
 
@@ -419,11 +419,11 @@ pub trait MetadataExt {
     /// }
     /// ```
     ///
-    /// [`FILETIME`]: https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
+    /// [`FILETIME`]: https://docs.microsoft.com/windows/win32/api/minwinbase/ns-minwinbase-filetime
     #[stable(feature = "metadata_ext", since = "1.1.0")]
     fn last_write_time(&self) -> u64;
 
-    /// Returns the value of the `nFileSize{High,Low}` fields of this
+    /// Returns the value of the `nFileSize` fields of this
     /// metadata.
     ///
     /// The returned value does not have meaning for directories.
@@ -462,7 +462,7 @@ pub trait MetadataExt {
     #[unstable(feature = "windows_by_handle", issue = "63010")]
     fn number_of_links(&self) -> Option<u32>;
 
-    /// Returns the value of the `nFileIndex{Low,High}` fields of this
+    /// Returns the value of the `nFileIndex` fields of this
     /// metadata.
     ///
     /// This will return `None` if the `Metadata` instance was created from a
@@ -471,10 +471,14 @@ pub trait MetadataExt {
     #[unstable(feature = "windows_by_handle", issue = "63010")]
     fn file_index(&self) -> Option<u64>;
 
-    /// Returns the change time, which is the last time file metadata was changed, such as
-    /// renames, attributes, etc
+    /// Returns the value of the `ChangeTime` fields of this metadata.
     ///
-    /// This will return `None` if the `Metadata` instance was not created using the `FILE_BASIC_INFO` type.
+    /// `ChangeTime` is the last time file metadata was changed, such as
+    /// renames, attributes, etc.
+    ///
+    /// This will return `None` if `Metadata` instance was created from a call to
+    /// `DirEntry::metadata` or if the `target_vendor` is outside the current platform
+    /// support for this api.
     #[unstable(feature = "windows_change_time", issue = "121478")]
     fn change_time(&self) -> Option<u64>;
 }

library/std/src/sys/pal/unix/fs.rs

@@ -1731,7 +1731,7 @@ pub fn link(original: &Path, link: &Path) -> io::Result<()> {
     run_path_with_cstr(original, &|original| {
         run_path_with_cstr(link, &|link| {
             cfg_if::cfg_if! {
-                if #[cfg(any(target_os = "vxworks", target_os = "redox", target_os = "android", target_os = "espidf", target_os = "horizon", target_os = "vita", target_os = "nto"))] {
+                if #[cfg(any(target_os = "vxworks", target_os = "redox", target_os = "android", target_os = "espidf", target_os = "horizon", target_os = "vita", target_env = "nto70"))] {
                     // VxWorks, Redox and ESP-IDF lack `linkat`, so use `link` instead. POSIX leaves
                     // it implementation-defined whether `link` follows symlinks, so rely on the
                     // `symlink_hard_link` test in library/std/src/fs/tests.rs to check the behavior.

library/std/src/sys/pal/windows/mod.rs

@@ -122,6 +122,7 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
         c::ERROR_NOT_SAME_DEVICE => return CrossesDevices,
         c::ERROR_TOO_MANY_LINKS => return TooManyLinks,
         c::ERROR_FILENAME_EXCED_RANGE => return InvalidFilename,
+        c::ERROR_CANT_RESOLVE_FILENAME => return FilesystemLoop,
         _ => {}
     }
 
@@ -139,6 +140,7 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
         c::WSAEHOSTUNREACH => HostUnreachable,
         c::WSAENETDOWN => NetworkDown,
         c::WSAENETUNREACH => NetworkUnreachable,
+        c::WSAEDQUOT => FilesystemQuotaExceeded,
 
         _ => Uncategorized,
     }

library/std/src/sys/personality/dwarf/eh.rs

@@ -54,10 +54,10 @@ pub enum EHAction {
     Terminate,
 }
 
-/// 32-bit Apple ARM uses SjLj exceptions, except for watchOS.
+/// 32-bit ARM Darwin platforms uses SjLj exceptions.
 ///
-/// I.e. iOS and tvOS, as those are the only Apple OSes that used 32-bit ARM
-/// devices.
+/// The exception is watchOS armv7k (specifically that subarchitecture), which
+/// instead uses DWARF Call Frame Information (CFI) unwinding.
 ///
 /// <https://github.com/llvm/llvm-project/blob/llvmorg-18.1.4/clang/lib/Driver/ToolChains/Darwin.cpp#L3107-L3119>
 pub const USING_SJLJ_EXCEPTIONS: bool =

library/std/src/sys/personality/gcc.rs

@@ -95,14 +95,15 @@ const UNWIND_DATA_REG: (i32, i32) = (4, 5); // a0, a1
 
 cfg_if::cfg_if! {
     if #[cfg(all(
-            target_arch = "arm",
-            not(all(target_vendor = "apple", not(target_os = "watchos"))),
-            not(target_os = "netbsd"),
-        ))] {
+        target_arch = "arm",
+        not(target_vendor = "apple"),
+        not(target_os = "netbsd"),
+    ))] {
         /// personality fn called by [ARM EHABI][armeabi-eh]
         ///
-        /// Apple 32-bit ARM (but not watchOS) uses the default routine instead
-        /// since it uses "setjmp-longjmp" unwinding.
+        /// 32-bit ARM on iOS/tvOS/watchOS does not use ARM EHABI, it uses
+        /// either "setjmp-longjmp" unwinding or DWARF CFI unwinding, which is
+        /// handled by the default routine.
         ///
         /// [armeabi-eh]: https://web.archive.org/web/20190728160938/https://infocenter.arm.com/help/topic/com.arm.doc.ihi0038b/IHI0038B_ehabi.pdf
         #[lang = "eh_personality"]

library/stdarch

@@ -1 +1 @@
-Subproject commit d9466edb4c53cece8686ee6e17b028436ddf4151
+Subproject commit ace72223a0e321c1b0a37b5862aa756fe8ab5111

library/unwind/src/libunwind.rs

@@ -33,10 +33,10 @@ pub const unwinder_private_data_size: usize = 2;
 #[cfg(all(target_arch = "x86_64", target_os = "windows"))]
 pub const unwinder_private_data_size: usize = 6;
 
-#[cfg(all(target_arch = "arm", not(all(target_vendor = "apple", not(target_os = "watchos")))))]
+#[cfg(all(target_arch = "arm", not(target_vendor = "apple")))]
 pub const unwinder_private_data_size: usize = 20;
 
-#[cfg(all(target_arch = "arm", all(target_vendor = "apple", not(target_os = "watchos"))))]
+#[cfg(all(target_arch = "arm", target_vendor = "apple"))]
 pub const unwinder_private_data_size: usize = 5;
 
 #[cfg(all(target_arch = "aarch64", target_pointer_width = "64", not(target_os = "windows")))]
@@ -123,8 +123,11 @@ extern "C" {
 }
 
 cfg_if::cfg_if! {
-if #[cfg(any(all(target_vendor = "apple", not(target_os = "watchos")), target_os = "netbsd", not(target_arch = "arm")))] {
+if #[cfg(any(target_vendor = "apple", target_os = "netbsd", not(target_arch = "arm")))] {
     // Not ARM EHABI
+    //
+    // 32-bit ARM on iOS/tvOS/watchOS use either DWARF/Compact unwinding or
+    // "setjmp-longjmp" / SjLj unwinding.
     #[repr(C)]
     #[derive(Copy, Clone, PartialEq)]
     pub enum _Unwind_Action {
@@ -259,8 +262,8 @@ if #[cfg(any(all(target_vendor = "apple", not(target_os = "watchos")), target_os
 
 cfg_if::cfg_if! {
 if #[cfg(all(target_vendor = "apple", not(target_os = "watchos"), target_arch = "arm"))] {
-    // 32-bit ARM Apple (except for watchOS) uses SjLj and does not provide
-    // _Unwind_Backtrace()
+    // 32-bit ARM Apple (except for watchOS armv7k specifically) uses SjLj and
+    // does not provide _Unwind_Backtrace()
     extern "C-unwind" {
         pub fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
     }

src/bootstrap/src/core/build_steps/compile.rs

@@ -15,6 +15,7 @@ use std::path::{Path, PathBuf};
 use std::process::Stdio;
 use std::{env, fs, str};
 
+use build_helper::git::get_closest_merge_commit;
 use serde_derive::Deserialize;
 
 use crate::core::build_steps::tool::SourceType;
@@ -26,8 +27,7 @@ use crate::core::builder::{
 use crate::core::config::{DebuginfoLevel, LlvmLibunwind, RustcLto, TargetSelection};
 use crate::utils::exec::command;
 use crate::utils::helpers::{
-    self, exe, get_clang_cl_resource_dir, get_closest_merge_base_commit, is_debug_info, is_dylib,
-    symlink_dir, t, up_to_date,
+    self, exe, get_clang_cl_resource_dir, is_debug_info, is_dylib, symlink_dir, t, up_to_date,
 };
 use crate::{CLang, Compiler, DependencyType, GitRepo, Mode, LLVM_TOOLS};
 
@@ -127,13 +127,9 @@ impl Step for Std {
         // the `rust.download-rustc=true` option.
         let force_recompile =
             if builder.rust_info().is_managed_git_subrepository() && builder.download_rustc() {
-                let closest_merge_commit = get_closest_merge_base_commit(
-                    Some(&builder.src),
-                    &builder.config.git_config(),
-                    &builder.config.stage0_metadata.config.git_merge_commit_email,
-                    &[],
-                )
-                .unwrap();
+                let closest_merge_commit =
+                    get_closest_merge_commit(Some(&builder.src), &builder.config.git_config(), &[])
+                        .unwrap();
 
                 // Check if `library` has changes (returns false otherwise)
                 !t!(helpers::git(Some(&builder.src))

src/bootstrap/src/core/build_steps/format.rs

@@ -200,6 +200,11 @@ pub fn format(build: &Builder<'_>, check: bool, all: bool, paths: &[PathBuf]) {
                 adjective = Some("modified");
                 match get_modified_rs_files(build) {
                     Ok(Some(files)) => {
+                        if files.is_empty() {
+                            println!("fmt info: No modified files detected for formatting.");
+                            return;
+                        }
+
                         for file in files {
                             override_builder.add(&format!("/{file}")).expect(&file);
                         }

src/bootstrap/src/core/build_steps/llvm.rs

@@ -16,6 +16,7 @@ use std::sync::OnceLock;
 use std::{env, io};
 
 use build_helper::ci::CiEnv;
+use build_helper::git::get_closest_merge_commit;
 
 use crate::core::builder::{Builder, RunConfig, ShouldRun, Step};
 use crate::core::config::{Config, TargetSelection};
@@ -153,10 +154,9 @@ pub fn prebuilt_llvm_config(builder: &Builder<'_>, target: TargetSelection) -> L
 /// This retrieves the LLVM sha we *want* to use, according to git history.
 pub(crate) fn detect_llvm_sha(config: &Config, is_git: bool) -> String {
     let llvm_sha = if is_git {
-        helpers::get_closest_merge_base_commit(
+        get_closest_merge_commit(
             Some(&config.src),
             &config.git_config(),
-            &config.stage0_metadata.config.git_merge_commit_email,
             &[
                 config.src.join("src/llvm-project"),
                 config.src.join("src/bootstrap/download-ci-llvm-stamp"),

src/bootstrap/src/core/build_steps/suggest.rs

@@ -17,6 +17,7 @@ pub fn suggest(builder: &Builder<'_>, run: bool) {
         .tool_cmd(Tool::SuggestTests)
         .env("SUGGEST_TESTS_GIT_REPOSITORY", git_config.git_repository)
         .env("SUGGEST_TESTS_NIGHTLY_BRANCH", git_config.nightly_branch)
+        .env("SUGGEST_TESTS_MERGE_COMMIT_EMAIL", git_config.git_merge_commit_email)
         .run_capture_stdout(builder)
         .stdout();
 

src/bootstrap/src/core/build_steps/test.rs

@@ -2098,6 +2098,7 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         let git_config = builder.config.git_config();
         cmd.arg("--git-repository").arg(git_config.git_repository);
         cmd.arg("--nightly-branch").arg(git_config.nightly_branch);
+        cmd.arg("--git-merge-commit-email").arg(git_config.git_merge_commit_email);
         cmd.force_coloring_in_ci();
 
         #[cfg(feature = "build-metrics")]

src/bootstrap/src/core/build_steps/tool.rs

@@ -1,6 +1,8 @@
 use std::path::PathBuf;
 use std::{env, fs};
 
+use build_helper::git::get_closest_merge_commit;
+
 use crate::core::build_steps::compile;
 use crate::core::build_steps::toolstate::ToolState;
 use crate::core::builder;
@@ -8,7 +10,7 @@ use crate::core::builder::{Builder, Cargo as CargoCommand, RunConfig, ShouldRun,
 use crate::core::config::TargetSelection;
 use crate::utils::channel::GitInfo;
 use crate::utils::exec::{command, BootstrapCommand};
-use crate::utils::helpers::{add_dylib_path, exe, get_closest_merge_base_commit, git, t};
+use crate::utils::helpers::{add_dylib_path, exe, git, t};
 use crate::{gha, Compiler, Kind, Mode};
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
@@ -576,10 +578,9 @@ impl Step for Rustdoc {
             && target_compiler.stage > 0
             && builder.rust_info().is_managed_git_subrepository()
         {
-            let commit = get_closest_merge_base_commit(
+            let commit = get_closest_merge_commit(
                 Some(&builder.config.src),
                 &builder.config.git_config(),
-                &builder.config.stage0_metadata.config.git_merge_commit_email,
                 &[],
             )
             .unwrap();

src/bootstrap/src/core/config/config.rs

@@ -14,7 +14,7 @@ use std::sync::OnceLock;
 use std::{cmp, env, fs};
 
 use build_helper::exit;
-use build_helper::git::{output_result, GitConfig};
+use build_helper::git::{get_closest_merge_commit, output_result, GitConfig};
 use serde::{Deserialize, Deserializer};
 use serde_derive::Deserialize;
 
@@ -24,7 +24,7 @@ pub use crate::core::config::flags::Subcommand;
 use crate::core::config::flags::{Color, Flags, Warnings};
 use crate::utils::cache::{Interned, INTERNER};
 use crate::utils::channel::{self, GitInfo};
-use crate::utils::helpers::{self, exe, get_closest_merge_base_commit, output, t};
+use crate::utils::helpers::{self, exe, output, t};
 
 macro_rules! check_ci_llvm {
     ($name:expr) => {
@@ -2512,6 +2512,7 @@ impl Config {
         GitConfig {
             git_repository: &self.stage0_metadata.config.git_repository,
             nightly_branch: &self.stage0_metadata.config.nightly_branch,
+            git_merge_commit_email: &self.stage0_metadata.config.git_merge_commit_email,
         }
     }
 
@@ -2688,13 +2689,7 @@ impl Config {
 
         // Look for a version to compare to based on the current commit.
         // Only commits merged by bors will have CI artifacts.
-        let commit = get_closest_merge_base_commit(
-            Some(&self.src),
-            &self.git_config(),
-            &self.stage0_metadata.config.git_merge_commit_email,
-            &[],
-        )
-        .unwrap();
+        let commit = get_closest_merge_commit(Some(&self.src), &self.git_config(), &[]).unwrap();
         if commit.is_empty() {
             println!("ERROR: could not find commit hash for downloading rustc");
             println!("HELP: maybe your repository history is too shallow?");
@@ -2786,13 +2781,7 @@ impl Config {
     ) -> Option<String> {
         // Look for a version to compare to based on the current commit.
         // Only commits merged by bors will have CI artifacts.
-        let commit = get_closest_merge_base_commit(
-            Some(&self.src),
-            &self.git_config(),
-            &self.stage0_metadata.config.git_merge_commit_email,
-            &[],
-        )
-        .unwrap();
+        let commit = get_closest_merge_commit(Some(&self.src), &self.git_config(), &[]).unwrap();
         if commit.is_empty() {
             println!("error: could not find commit hash for downloading components from CI");
             println!("help: maybe your repository history is too shallow?");

src/bootstrap/src/utils/helpers.rs

@@ -10,7 +10,6 @@ use std::sync::OnceLock;
 use std::time::{Instant, SystemTime, UNIX_EPOCH};
 use std::{env, fs, io, str};
 
-use build_helper::git::{get_git_merge_base, output_result, GitConfig};
 use build_helper::util::fail;
 
 use crate::core::builder::Builder;
@@ -523,28 +522,6 @@ pub fn git(source_dir: Option<&Path>) -> BootstrapCommand {
     git
 }
 
-/// Returns the closest commit available from upstream for the given `author` and `target_paths`.
-///
-/// If it fails to find the commit from upstream using `git merge-base`, fallbacks to HEAD.
-pub fn get_closest_merge_base_commit(
-    source_dir: Option<&Path>,
-    config: &GitConfig<'_>,
-    author: &str,
-    target_paths: &[PathBuf],
-) -> Result<String, String> {
-    let mut git = git(source_dir);
-
-    let merge_base = get_git_merge_base(config, source_dir).unwrap_or_else(|_| "HEAD".into());
-
-    git.args(["rev-list", &format!("--author={author}"), "-n1", "--first-parent", &merge_base]);
-
-    if !target_paths.is_empty() {
-        git.arg("--").args(target_paths);
-    }
-
-    Ok(output_result(git.as_command_mut())?.trim().to_owned())
-}
-
 /// Sets the file times for a given file at `path`.
 pub fn set_file_times<P: AsRef<Path>>(path: P, times: fs::FileTimes) -> io::Result<()> {
     // Windows requires file to be writable to modify file times. But on Linux CI the file does not

src/llvm-project

@@ -1 +1 @@
-Subproject commit 2b259b3c201f939f2ed8d2fb0a0e9b37dd2d1321
+Subproject commit 4b8d29c585687084bbcf21471e04f279d1eddc0a

src/tools/build_helper/src/git.rs

@@ -1,9 +1,10 @@
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 
 pub struct GitConfig<'a> {
     pub git_repository: &'a str,
     pub nightly_branch: &'a str,
+    pub git_merge_commit_email: &'a str,
 }
 
 /// Runs a command and returns the output
@@ -95,7 +96,11 @@ pub fn updated_master_branch(
     Err("Cannot find any suitable upstream master branch".to_owned())
 }
 
-pub fn get_git_merge_base(
+/// Finds the nearest merge commit by comparing the local `HEAD` with the upstream branch's state.
+/// To work correctly, the upstream remote must be properly configured using `git remote add <name> <url>`.
+/// In most cases `get_closest_merge_commit` is the function you are looking for as it doesn't require remote
+/// to be configured.
+fn git_upstream_merge_base(
     config: &GitConfig<'_>,
     git_dir: Option<&Path>,
 ) -> Result<String, String> {
@@ -107,6 +112,38 @@ pub fn get_git_merge_base(
     Ok(output_result(git.arg("merge-base").arg(&updated_master).arg("HEAD"))?.trim().to_owned())
 }
 
+/// Searches for the nearest merge commit in the repository that also exists upstream.
+///
+/// If it fails to find the upstream remote, it then looks for the most recent commit made
+/// by the merge bot by matching the author's email address with the merge bot's email.
+pub fn get_closest_merge_commit(
+    git_dir: Option<&Path>,
+    config: &GitConfig<'_>,
+    target_paths: &[PathBuf],
+) -> Result<String, String> {
+    let mut git = Command::new("git");
+
+    if let Some(git_dir) = git_dir {
+        git.current_dir(git_dir);
+    }
+
+    let merge_base = git_upstream_merge_base(config, git_dir).unwrap_or_else(|_| "HEAD".into());
+
+    git.args([
+        "rev-list",
+        &format!("--author={}", config.git_merge_commit_email),
+        "-n1",
+        "--first-parent",
+        &merge_base,
+    ]);
+
+    if !target_paths.is_empty() {
+        git.arg("--").args(target_paths);
+    }
+
+    Ok(output_result(&mut git)?.trim().to_owned())
+}
+
 /// Returns the files that have been modified in the current branch compared to the master branch.
 /// The `extensions` parameter can be used to filter the files by their extension.
 /// Does not include removed files.
@@ -116,7 +153,7 @@ pub fn get_git_modified_files(
     git_dir: Option<&Path>,
     extensions: &[&str],
 ) -> Result<Option<Vec<String>>, String> {
-    let merge_base = get_git_merge_base(config, git_dir)?;
+    let merge_base = get_closest_merge_commit(git_dir, config, &[])?;
 
     let mut git = Command::new("git");
     if let Some(git_dir) = git_dir {

src/tools/compiletest/src/common.rs

@@ -384,6 +384,7 @@ pub struct Config {
     // Needed both to construct build_helper::git::GitConfig
     pub git_repository: String,
     pub nightly_branch: String,
+    pub git_merge_commit_email: String,
 
     /// True if the profiler runtime is enabled for this target.
     /// Used by the "needs-profiler-support" header in test files.
@@ -461,7 +462,11 @@ impl Config {
     }
 
     pub fn git_config(&self) -> GitConfig<'_> {
-        GitConfig { git_repository: &self.git_repository, nightly_branch: &self.nightly_branch }
+        GitConfig {
+            git_repository: &self.git_repository,
+            nightly_branch: &self.nightly_branch,
+            git_merge_commit_email: &self.git_merge_commit_email,
+        }
     }
 }
 

src/tools/compiletest/src/header/tests.rs

@@ -148,6 +148,7 @@ impl ConfigBuilder {
             self.target.as_deref().unwrap_or("x86_64-unknown-linux-gnu"),
             "--git-repository=",
             "--nightly-branch=",
+            "--git-merge-commit-email=",
         ];
         let mut args: Vec<String> = args.iter().map(ToString::to_string).collect();
 

src/tools/compiletest/src/lib.rs

@@ -163,7 +163,13 @@ pub fn parse_config(args: Vec<String>) -> Config {
         )
         .optopt("", "edition", "default Rust edition", "EDITION")
         .reqopt("", "git-repository", "name of the git repository", "ORG/REPO")
-        .reqopt("", "nightly-branch", "name of the git branch for nightly", "BRANCH");
+        .reqopt("", "nightly-branch", "name of the git branch for nightly", "BRANCH")
+        .reqopt(
+            "",
+            "git-merge-commit-email",
+            "email address used for finding merge commits",
+            "EMAIL",
+        );
 
     let (argv0, args_) = args.split_first().unwrap();
     if args.len() == 1 || args[1] == "-h" || args[1] == "--help" {
@@ -346,6 +352,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
 
         git_repository: matches.opt_str("git-repository").unwrap(),
         nightly_branch: matches.opt_str("nightly-branch").unwrap(),
+        git_merge_commit_email: matches.opt_str("git-merge-commit-email").unwrap(),
 
         profiler_support: matches.opt_present("profiler-support"),
     }

src/tools/miri/src/intrinsics/simd.rs

@@ -666,22 +666,19 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 let (right, right_len) = this.operand_to_simd(right)?;
                 let (dest, dest_len) = this.mplace_to_simd(dest)?;
 
-                // `index` is an array, not a SIMD type
-                let ty::Array(_, index_len) = index.layout.ty.kind() else {
-                    span_bug!(
-                        this.cur_span(),
-                        "simd_shuffle index argument has non-array type {}",
-                        index.layout.ty
-                    )
+                // `index` is an array or a SIMD type
+                let (index, index_len) = match index.layout.ty.kind() {
+                    // FIXME: remove this once `index` must always be a SIMD vector.
+                    ty::Array(..) => (index.assert_mem_place(), index.len(this)?),
+                    _ => this.operand_to_simd(index)?,
                 };
-                let index_len = index_len.eval_target_usize(*this.tcx, this.param_env());
 
                 assert_eq!(left_len, right_len);
                 assert_eq!(index_len, dest_len);
 
                 for i in 0..dest_len {
                     let src_index: u64 = this
-                        .read_immediate(&this.project_index(index, i)?)?
+                        .read_immediate(&this.project_index(&index, i)?)?
                         .to_scalar()
                         .to_u32()?
                         .into();

src/tools/miri/tests/fail/intrinsics/ptr_offset_unsigned_overflow.rs

@@ -0,0 +1,7 @@
+fn main() {
+    let x = &[0i32; 2];
+    let x = x.as_ptr().wrapping_add(1);
+    // If the `!0` is interpreted as `isize`, it is just `-1` and hence harmless.
+    // However, this is unsigned arithmetic, so really this is `usize::MAX` and hence UB.
+    unsafe { x.byte_add(!0).read() }; //~ERROR: does not fit in an `isize`
+}

src/tools/miri/tests/fail/intrinsics/ptr_offset_unsigned_overflow.stderr

@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing pointer arithmetic: the total offset in bytes does not fit in an `isize`
+  --> $DIR/ptr_offset_unsigned_overflow.rs:LL:CC
+   |
+LL |     unsafe { x.byte_add(!0).read() };
+   |              ^^^^^^^^^^^^^^ overflowing pointer arithmetic: the total offset in bytes does not fit in an `isize`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_unsigned_overflow.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+

src/tools/miri/tests/pass/intrinsics/portable-simd.rs

@@ -620,6 +620,10 @@ fn simd_intrinsics() {
         );
         assert_eq!(simd_shuffle_generic::<_, i32x4, { &[3, 1, 0, 2] }>(a, b), a,);
         assert_eq!(simd_shuffle::<_, _, i32x4>(a, b, const { [3u32, 1, 0, 2] }), a,);
+        assert_eq!(
+            simd_shuffle::<_, _, i32x4>(a, b, const { u32x4::from_array([3u32, 1, 0, 2]) }),
+            a,
+        );
         assert_eq!(
             simd_shuffle_generic::<_, i32x4, { &[7, 5, 4, 6] }>(a, b),
             i32x4::from_array([4, 2, 1, 10]),
@@ -628,6 +632,10 @@ fn simd_intrinsics() {
             simd_shuffle::<_, _, i32x4>(a, b, const { [7u32, 5, 4, 6] }),
             i32x4::from_array([4, 2, 1, 10]),
         );
+        assert_eq!(
+            simd_shuffle::<_, _, i32x4>(a, b, const { u32x4::from_array([7u32, 5, 4, 6]) }),
+            i32x4::from_array([4, 2, 1, 10]),
+        );
     }
 }