Merge pull request #4532 from rust-lang/rustup-2025-08-20

Automatic Rustup

Cargo.lock

@@ -4812,6 +4812,7 @@ dependencies = [
  "serde_json",
  "sha2",
  "smallvec",
+ "stringdex",
  "tempfile",
  "threadpool",
  "tracing",
@@ -5225,6 +5226,15 @@ dependencies = [
  "quote",
 ]
 
+[[package]]
+name = "stringdex"
+version = "0.0.1-alpha4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2841fd43df5b1ff1b042e167068a1fe9b163dc93041eae56ab2296859013a9a0"
+dependencies = [
+ "stacker",
+]
+
 [[package]]
 name = "strsim"
 version = "0.11.1"

compiler/rustc_attr_parsing/messages.ftl

@@ -12,9 +12,11 @@ attr_parsing_empty_attribute =
 
 attr_parsing_invalid_target = `#[{$name}]` attribute cannot be used on {$target}
     .help = `#[{$name}]` can {$only}be applied to {$applied}
+    .suggestion = remove the attribute
 attr_parsing_invalid_target_lint = `#[{$name}]` attribute cannot be used on {$target}
     .warn = {-attr_parsing_previously_accepted}
     .help = `#[{$name}]` can {$only}be applied to {$applied}
+    .suggestion = remove the attribute
 
 attr_parsing_empty_confusables =
     expected at least one confusable name

compiler/rustc_attr_parsing/src/attributes/deprecation.rs

@@ -54,6 +54,8 @@ impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
         Allow(Target::TyAlias),
         Allow(Target::Use),
         Allow(Target::ForeignFn),
+        Allow(Target::ForeignStatic),
+        Allow(Target::ForeignTy),
         Allow(Target::Field),
         Allow(Target::Trait),
         Allow(Target::AssocTy),

compiler/rustc_attr_parsing/src/attributes/inline.rs

@@ -62,8 +62,8 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
                 }
             }
             ArgParser::NameValue(_) => {
-                let suggestions =
-                    <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "inline");
+                let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
+                    .suggestions(cx.attr_style, "inline");
                 let span = cx.attr_span;
                 cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                 return None;

compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs

@@ -107,7 +107,7 @@ impl<S: Stage> AttributeParser<S> for MacroUseParser {
                     }
                 }
                 ArgParser::NameValue(_) => {
-                    let suggestions = MACRO_USE_TEMPLATE.suggestions(false, sym::macro_use);
+                    let suggestions = MACRO_USE_TEMPLATE.suggestions(cx.attr_style, sym::macro_use);
                     cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
                         num_suggestions: suggestions.len(),
                         suggestions: DiagArgValue::StrListSepByAnd(

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -43,6 +43,7 @@ pub(crate) mod no_implicit_prelude;
 pub(crate) mod non_exhaustive;
 pub(crate) mod path;
 pub(crate) mod proc_macro_attrs;
+pub(crate) mod prototype;
 pub(crate) mod repr;
 pub(crate) mod rustc_internal;
 pub(crate) mod semantics;

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -1,10 +1,12 @@
 use rustc_errors::DiagArgValue;
 use rustc_feature::{AttributeTemplate, template};
 use rustc_hir::attrs::AttributeKind;
+use rustc_hir::{MethodKind, Target};
 use rustc_span::{Symbol, sym};
 
 use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
-use crate::context::{ALL_TARGETS, AcceptContext, AllowedTargets, Stage};
+use crate::context::MaybeWarn::{Allow, Error};
+use crate::context::{AcceptContext, AllowedTargets, Stage};
 use crate::parser::ArgParser;
 use crate::session_diagnostics;
 pub(crate) struct MustUseParser;
@@ -13,7 +15,21 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
     const PATH: &[Symbol] = &[sym::must_use];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS); //FIXME Still checked fully in `check_attr.rs`
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowListWarnRest(&[
+        Allow(Target::Fn),
+        Allow(Target::Enum),
+        Allow(Target::Struct),
+        Allow(Target::Union),
+        Allow(Target::Method(MethodKind::Trait { body: false })),
+        Allow(Target::Method(MethodKind::Trait { body: true })),
+        Allow(Target::Method(MethodKind::Inherent)),
+        Allow(Target::ForeignFn),
+        // `impl Trait` in return position can trip
+        // `unused_must_use` if `Trait` is marked as
+        // `#[must_use]`
+        Allow(Target::Trait),
+        Error(Target::WherePredicate),
+    ]);
     const TEMPLATE: AttributeTemplate = template!(
         Word, NameValueStr: "reason",
         "https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute"
@@ -35,8 +51,8 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
                     Some(value_str)
                 }
                 ArgParser::List(_) => {
-                    let suggestions =
-                        <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "must_use");
+                    let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
+                        .suggestions(cx.attr_style, "must_use");
                     cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
                         num_suggestions: suggestions.len(),
                         suggestions: DiagArgValue::StrListSepByAnd(

compiler/rustc_attr_parsing/src/attributes/prototype.rs

@@ -0,0 +1,140 @@
+//! Attributes that are only used on function prototypes.
+
+use rustc_feature::{AttributeTemplate, template};
+use rustc_hir::Target;
+use rustc_hir::attrs::{AttributeKind, MirDialect, MirPhase};
+use rustc_span::{Span, Symbol, sym};
+
+use super::{AttributeOrder, OnDuplicate};
+use crate::attributes::SingleAttributeParser;
+use crate::context::{AcceptContext, AllowedTargets, MaybeWarn, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct CustomMirParser;
+
+impl<S: Stage> SingleAttributeParser<S> for CustomMirParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::custom_mir];
+
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
+
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[MaybeWarn::Allow(Target::Fn)]);
+
+    const TEMPLATE: AttributeTemplate = template!(List: &[r#"dialect = "...", phase = "...""#]);
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let Some(list) = args.list() else {
+            cx.expected_list(cx.attr_span);
+            return None;
+        };
+
+        let mut dialect = None;
+        let mut phase = None;
+        let mut failed = false;
+
+        for item in list.mixed() {
+            let Some(meta_item) = item.meta_item() else {
+                cx.expected_name_value(item.span(), None);
+                failed = true;
+                break;
+            };
+
+            if let Some(arg) = meta_item.word_is(sym::dialect) {
+                extract_value(cx, sym::dialect, arg, meta_item.span(), &mut dialect, &mut failed);
+            } else if let Some(arg) = meta_item.word_is(sym::phase) {
+                extract_value(cx, sym::phase, arg, meta_item.span(), &mut phase, &mut failed);
+            } else if let Some(word) = meta_item.path().word() {
+                let word = word.to_string();
+                cx.unknown_key(meta_item.span(), word, &["dialect", "phase"]);
+                failed = true;
+            } else {
+                cx.expected_name_value(meta_item.span(), None);
+                failed = true;
+            };
+        }
+
+        let dialect = parse_dialect(cx, dialect, &mut failed);
+        let phase = parse_phase(cx, phase, &mut failed);
+
+        if failed {
+            return None;
+        }
+
+        Some(AttributeKind::CustomMir(dialect, phase, cx.attr_span))
+    }
+}
+
+fn extract_value<S: Stage>(
+    cx: &mut AcceptContext<'_, '_, S>,
+    key: Symbol,
+    arg: &ArgParser<'_>,
+    span: Span,
+    out_val: &mut Option<(Symbol, Span)>,
+    failed: &mut bool,
+) {
+    if out_val.is_some() {
+        cx.duplicate_key(span, key);
+        *failed = true;
+        return;
+    }
+
+    let Some(val) = arg.name_value() else {
+        cx.expected_single_argument(arg.span().unwrap_or(span));
+        *failed = true;
+        return;
+    };
+
+    let Some(value_sym) = val.value_as_str() else {
+        cx.expected_string_literal(val.value_span, Some(val.value_as_lit()));
+        *failed = true;
+        return;
+    };
+
+    *out_val = Some((value_sym, val.value_span));
+}
+
+fn parse_dialect<S: Stage>(
+    cx: &mut AcceptContext<'_, '_, S>,
+    dialect: Option<(Symbol, Span)>,
+    failed: &mut bool,
+) -> Option<(MirDialect, Span)> {
+    let (dialect, span) = dialect?;
+
+    let dialect = match dialect {
+        sym::analysis => MirDialect::Analysis,
+        sym::built => MirDialect::Built,
+        sym::runtime => MirDialect::Runtime,
+
+        _ => {
+            cx.expected_specific_argument(span, vec!["analysis", "built", "runtime"]);
+            *failed = true;
+            return None;
+        }
+    };
+
+    Some((dialect, span))
+}
+
+fn parse_phase<S: Stage>(
+    cx: &mut AcceptContext<'_, '_, S>,
+    phase: Option<(Symbol, Span)>,
+    failed: &mut bool,
+) -> Option<(MirPhase, Span)> {
+    let (phase, span) = phase?;
+
+    let phase = match phase {
+        sym::initial => MirPhase::Initial,
+        sym::post_cleanup => MirPhase::PostCleanup,
+        sym::optimized => MirPhase::Optimized,
+
+        _ => {
+            cx.expected_specific_argument(span, vec!["initial", "post-cleanup", "optimized"]);
+            *failed = true;
+            return None;
+        }
+    };
+
+    Some((phase, span))
+}

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -54,6 +54,7 @@ const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
     Allow(Target::Static),
     Allow(Target::ForeignFn),
     Allow(Target::ForeignStatic),
+    Allow(Target::ExternCrate),
 ]);
 
 #[derive(Default)]

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -29,7 +29,7 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
                 ArgParser::NameValue(name_value) => {
                     let Some(str_value) = name_value.value_as_str() else {
                         let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
-                            .suggestions(false, "ignore");
+                            .suggestions(cx.attr_style, "ignore");
                         let span = cx.attr_span;
                         cx.emit_lint(
                             AttributeLintKind::IllFormedAttributeInput { suggestions },
@@ -40,8 +40,8 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
                     Some(str_value)
                 }
                 ArgParser::List(_) => {
-                    let suggestions =
-                        <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "ignore");
+                    let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
+                        .suggestions(cx.attr_style, "ignore");
                     let span = cx.attr_span;
                     cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                     return None;

compiler/rustc_attr_parsing/src/context.rs

@@ -5,7 +5,7 @@ use std::sync::LazyLock;
 
 use itertools::Itertools;
 use private::Sealed;
-use rustc_ast::{self as ast, LitKind, MetaItemLit, NodeId};
+use rustc_ast::{self as ast, AttrStyle, LitKind, MetaItemLit, NodeId};
 use rustc_errors::{DiagCtxtHandle, Diagnostic};
 use rustc_feature::{AttributeTemplate, Features};
 use rustc_hir::attrs::AttributeKind;
@@ -46,6 +46,7 @@ use crate::attributes::path::PathParser as PathAttributeParser;
 use crate::attributes::proc_macro_attrs::{
     ProcMacroAttributeParser, ProcMacroDeriveParser, ProcMacroParser, RustcBuiltinMacroParser,
 };
+use crate::attributes::prototype::CustomMirParser;
 use crate::attributes::repr::{AlignParser, ReprParser};
 use crate::attributes::rustc_internal::{
     RustcLayoutScalarValidRangeEnd, RustcLayoutScalarValidRangeStart,
@@ -167,6 +168,7 @@ attribute_parsers!(
 
         // tidy-alphabetical-start
         Single<CoverageParser>,
+        Single<CustomMirParser>,
         Single<DeprecationParser>,
         Single<DummyParser>,
         Single<ExportNameParser>,
@@ -313,6 +315,7 @@ pub struct AcceptContext<'f, 'sess, S: Stage> {
     /// The span of the attribute currently being parsed
     pub(crate) attr_span: Span,
 
+    pub(crate) attr_style: AttrStyle,
     /// The expected structure of the attribute.
     ///
     /// Used in reporting errors to give a hint to users what the attribute *should* look like.
@@ -394,6 +397,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                     i.kind.is_bytestr().then(|| self.sess().source_map().start_point(i.span))
                 }),
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -404,6 +408,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedIntegerLiteral,
+            attr_style: self.attr_style,
         })
     }
 
@@ -414,6 +419,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedList,
+            attr_style: self.attr_style,
         })
     }
 
@@ -424,6 +430,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedNoArgs,
+            attr_style: self.attr_style,
         })
     }
 
@@ -435,6 +442,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedIdentifier,
+            attr_style: self.attr_style,
         })
     }
 
@@ -447,6 +455,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedNameValue(name),
+            attr_style: self.attr_style,
         })
     }
 
@@ -458,6 +467,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::DuplicateKey(key),
+            attr_style: self.attr_style,
         })
     }
 
@@ -470,6 +480,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::UnexpectedLiteral,
+            attr_style: self.attr_style,
         })
     }
 
@@ -480,6 +491,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedSingleArgument,
+            attr_style: self.attr_style,
         })
     }
 
@@ -490,6 +502,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedAtLeastOneArgument,
+            attr_style: self.attr_style,
         })
     }
 
@@ -508,6 +521,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: false,
                 list: false,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -526,6 +540,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: false,
                 list: true,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -544,6 +559,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: true,
                 list: false,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -802,6 +818,7 @@ impl<'sess> AttributeParser<'sess, Early> {
                 },
             },
             attr_span: attr.span,
+            attr_style: attr.style,
             template,
             attr_path: path.get_attribute_path(),
         };
@@ -912,6 +929,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                                     emit_lint: &mut emit_lint,
                                 },
                                 attr_span: lower_span(attr.span),
+                                attr_style: attr.style,
                                 template: &accept.template,
                                 attr_path: path.get_attribute_path(),
                             };
@@ -1060,6 +1078,9 @@ pub(crate) fn allowed_targets_applied(
         if !features.stmt_expr_attributes() {
             allowed_targets.retain(|t| !matches!(t, Target::Expression | Target::Statement));
         }
+        if !features.extern_types() {
+            allowed_targets.retain(|t| !matches!(t, Target::ForeignTy));
+        }
     }
 
     // We define groups of "similar" targets.

compiler/rustc_attr_parsing/src/lints.rs

@@ -53,6 +53,7 @@ pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<HirId>, lint_emi
                     target: target.plural_name(),
                     applied: applied.clone(),
                     only,
+                    attr_span: *span,
                 },
             ),
     }

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -1,6 +1,6 @@
 use std::num::IntErrorKind;
 
-use rustc_ast as ast;
+use rustc_ast::{self as ast, AttrStyle};
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level,
@@ -489,6 +489,8 @@ pub(crate) struct InvalidTargetLint {
     pub target: &'static str,
     pub applied: String,
     pub only: &'static str,
+    #[suggestion(code = "", applicability = "machine-applicable", style = "tool-only")]
+    pub attr_span: Span,
 }
 
 #[derive(Diagnostic)]
@@ -496,6 +498,7 @@ pub(crate) struct InvalidTargetLint {
 #[diag(attr_parsing_invalid_target)]
 pub(crate) struct InvalidTarget {
     #[primary_span]
+    #[suggestion(code = "", applicability = "machine-applicable", style = "tool-only")]
     pub span: Span,
     pub name: Symbol,
     pub target: &'static str,
@@ -579,6 +582,7 @@ pub(crate) enum AttributeParseErrorReason {
 pub(crate) struct AttributeParseError {
     pub(crate) span: Span,
     pub(crate) attr_span: Span,
+    pub(crate) attr_style: AttrStyle,
     pub(crate) template: AttributeTemplate,
     pub(crate) attribute: AttrPath,
     pub(crate) reason: AttributeParseErrorReason,
@@ -717,7 +721,8 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
         if let Some(link) = self.template.docs {
             diag.note(format!("for more information, visit <{link}>"));
         }
-        let suggestions = self.template.suggestions(false, &name);
+        let suggestions = self.template.suggestions(self.attr_style, &name);
+
         diag.span_suggestions(
             self.attr_span,
             if suggestions.len() == 1 {

compiler/rustc_borrowck/messages.ftl

@@ -90,7 +90,7 @@ borrowck_lifetime_constraints_error =
     lifetime may not live long enough
 
 borrowck_limitations_implies_static =
-    due to current limitations in the borrow checker, this implies a `'static` lifetime
+    due to a current limitation of the type system, this implies a `'static` lifetime
 
 borrowck_move_closure_suggestion =
     consider adding 'move' keyword before the nested closure

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -6,7 +6,9 @@ use rustc_abi::{FieldIdx, VariantIdx};
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::{Applicability, Diag, EmissionGuarantee, MultiSpan, listify};
 use rustc_hir::def::{CtorKind, Namespace};
-use rustc_hir::{self as hir, CoroutineKind, LangItem};
+use rustc_hir::{
+    self as hir, CoroutineKind, GenericBound, LangItem, WhereBoundPredicate, WherePredicateKind,
+};
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_infer::infer::{BoundRegionConversionTime, NllRegionVariableOrigin};
 use rustc_infer::traits::SelectionError;
@@ -658,25 +660,66 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
 
     /// Add a note to region errors and borrow explanations when higher-ranked regions in predicates
     /// implicitly introduce an "outlives `'static`" constraint.
+    ///
+    /// This is very similar to `fn suggest_static_lifetime_for_gat_from_hrtb` which handles this
+    /// note for failed type tests instead of outlives errors.
     fn add_placeholder_from_predicate_note<G: EmissionGuarantee>(
         &self,
-        err: &mut Diag<'_, G>,
+        diag: &mut Diag<'_, G>,
         path: &[OutlivesConstraint<'tcx>],
     ) {
-        let predicate_span = path.iter().find_map(|constraint| {
+        let tcx = self.infcx.tcx;
+        let Some((gat_hir_id, generics)) = path.iter().find_map(|constraint| {
             let outlived = constraint.sub;
             if let Some(origin) = self.regioncx.definitions.get(outlived)
-                && let NllRegionVariableOrigin::Placeholder(_) = origin.origin
-                && let ConstraintCategory::Predicate(span) = constraint.category
+                && let NllRegionVariableOrigin::Placeholder(placeholder) = origin.origin
+                && let Some(id) = placeholder.bound.kind.get_id()
+                && let Some(placeholder_id) = id.as_local()
+                && let gat_hir_id = tcx.local_def_id_to_hir_id(placeholder_id)
+                && let Some(generics_impl) =
+                    tcx.parent_hir_node(tcx.parent_hir_id(gat_hir_id)).generics()
             {
-                Some(span)
+                Some((gat_hir_id, generics_impl))
             } else {
                 None
             }
-        });
+        }) else {
+            return;
+        };
 
-        if let Some(span) = predicate_span {
-            err.span_note(span, "due to current limitations in the borrow checker, this implies a `'static` lifetime");
+        // Look for the where-bound which introduces the placeholder.
+        // As we're using the HIR, we need to handle both `for<'a> T: Trait<'a>`
+        // and `T: for<'a> Trait`<'a>.
+        for pred in generics.predicates {
+            let WherePredicateKind::BoundPredicate(WhereBoundPredicate {
+                bound_generic_params,
+                bounds,
+                ..
+            }) = pred.kind
+            else {
+                continue;
+            };
+            if bound_generic_params
+                .iter()
+                .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == gat_hir_id)
+                .is_some()
+            {
+                diag.span_note(pred.span, fluent::borrowck_limitations_implies_static);
+                return;
+            }
+            for bound in bounds.iter() {
+                if let GenericBound::Trait(bound) = bound {
+                    if bound
+                        .bound_generic_params
+                        .iter()
+                        .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == gat_hir_id)
+                        .is_some()
+                    {
+                        diag.span_note(bound.span, fluent::borrowck_limitations_implies_static);
+                        return;
+                    }
+                }
+            }
         }
     }
 

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -3,6 +3,7 @@
 
 use core::ops::ControlFlow;
 
+use either::Either;
 use hir::{ExprKind, Param};
 use rustc_abi::FieldIdx;
 use rustc_errors::{Applicability, Diag};
@@ -12,15 +13,16 @@ use rustc_middle::bug;
 use rustc_middle::hir::place::PlaceBase;
 use rustc_middle::mir::visit::PlaceContext;
 use rustc_middle::mir::{
-    self, BindingForm, Local, LocalDecl, LocalInfo, LocalKind, Location, Mutability, Place,
-    PlaceRef, ProjectionElem,
+    self, BindingForm, Body, BorrowKind, Local, LocalDecl, LocalInfo, LocalKind, Location,
+    Mutability, Operand, Place, PlaceRef, ProjectionElem, RawPtrKind, Rvalue, Statement,
+    StatementKind, TerminatorKind,
 };
 use rustc_middle::ty::{self, InstanceKind, Ty, TyCtxt, Upcast};
 use rustc_span::{BytePos, DesugaringKind, Span, Symbol, kw, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits;
-use tracing::debug;
+use tracing::{debug, trace};
 
 use crate::diagnostics::BorrowedContentSource;
 use crate::{MirBorrowckCtxt, session_diagnostics};
@@ -31,6 +33,33 @@ pub(crate) enum AccessKind {
     Mutate,
 }
 
+/// Finds all statements that assign directly to local (i.e., X = ...) and returns their
+/// locations.
+fn find_assignments(body: &Body<'_>, local: Local) -> Vec<Location> {
+    use rustc_middle::mir::visit::Visitor;
+
+    struct FindLocalAssignmentVisitor {
+        needle: Local,
+        locations: Vec<Location>,
+    }
+
+    impl<'tcx> Visitor<'tcx> for FindLocalAssignmentVisitor {
+        fn visit_local(&mut self, local: Local, place_context: PlaceContext, location: Location) {
+            if self.needle != local {
+                return;
+            }
+
+            if place_context.is_place_assignment() {
+                self.locations.push(location);
+            }
+        }
+    }
+
+    let mut visitor = FindLocalAssignmentVisitor { needle: local, locations: vec![] };
+    visitor.visit_body(body);
+    visitor.locations
+}
+
 impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     pub(crate) fn report_mutability_error(
         &mut self,
@@ -384,7 +413,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 }
             }
 
-            // Also suggest adding mut for upvars
+            // Also suggest adding mut for upvars.
             PlaceRef {
                 local,
                 projection: [proj_base @ .., ProjectionElem::Field(upvar_index, _)],
@@ -438,9 +467,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 }
             }
 
-            // complete hack to approximate old AST-borrowck
-            // diagnostic: if the span starts with a mutable borrow of
-            // a local variable, then just suggest the user remove it.
+            // Complete hack to approximate old AST-borrowck diagnostic: if the span starts
+            // with a mutable borrow of a local variable, then just suggest the user remove it.
             PlaceRef { local: _, projection: [] }
                 if self
                     .infcx
@@ -769,7 +797,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         );
     }
 
-    // point to span of upvar making closure call require mutable borrow
+    // Point to span of upvar making closure call that requires a mutable borrow
     fn show_mutating_upvar(
         &self,
         tcx: TyCtxt<'_>,
@@ -825,7 +853,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             } else {
                 bug!("not an upvar")
             };
-            // sometimes we deliberately don't store the name of a place when coming from a macro in
+            // Sometimes we deliberately don't store the name of a place when coming from a macro in
             // another crate. We generally want to limit those diagnostics a little, to hide
             // implementation details (such as those from pin!() or format!()). In that case show a
             // slightly different error message, or none at all if something else happened. In other
@@ -936,8 +964,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let def_id = tcx.hir_enclosing_body_owner(fn_call_id);
         let mut look_at_return = true;
 
-        // If the HIR node is a function or method call gets the def ID
-        // of the called function or method and the span and args of the call expr
+        // If the HIR node is a function or method call, get the DefId
+        // of the callee function or method, the span, and args of the call expr
         let get_call_details = || {
             let hir::Node::Expr(hir::Expr { hir_id, kind, .. }) = node else {
                 return None;
@@ -1051,7 +1079,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             let mut cur_expr = expr;
             while let ExprKind::MethodCall(path_segment, recv, _, _) = cur_expr.kind {
                 if path_segment.ident.name == sym::iter {
-                    // check `_ty` has `iter_mut` method
+                    // Check that the type has an `iter_mut` method.
                     let res = self
                         .infcx
                         .tcx
@@ -1081,38 +1109,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         }
     }
 
-    /// Finds all statements that assign directly to local (i.e., X = ...) and returns their
-    /// locations.
-    fn find_assignments(&self, local: Local) -> Vec<Location> {
-        use rustc_middle::mir::visit::Visitor;
-
-        struct FindLocalAssignmentVisitor {
-            needle: Local,
-            locations: Vec<Location>,
-        }
-
-        impl<'tcx> Visitor<'tcx> for FindLocalAssignmentVisitor {
-            fn visit_local(
-                &mut self,
-                local: Local,
-                place_context: PlaceContext,
-                location: Location,
-            ) {
-                if self.needle != local {
-                    return;
-                }
-
-                if place_context.is_place_assignment() {
-                    self.locations.push(location);
-                }
-            }
-        }
-
-        let mut visitor = FindLocalAssignmentVisitor { needle: local, locations: vec![] };
-        visitor.visit_body(self.body);
-        visitor.locations
-    }
-
     fn suggest_make_local_mut(&self, err: &mut Diag<'_>, local: Local, name: Symbol) {
         let local_decl = &self.body.local_decls[local];
 
@@ -1122,7 +1118,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let (is_trait_sig, is_local, local_trait) = self.is_error_in_trait(local);
 
         if is_trait_sig && !is_local {
-            // Do not suggest to change the signature when the trait comes from another crate.
+            // Do not suggest changing the signature when the trait comes from another crate.
             err.span_label(
                 local_decl.source_info.span,
                 format!("this is an immutable {pointer_desc}"),
@@ -1131,11 +1127,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         }
         let decl_span = local_decl.source_info.span;
 
-        let amp_mut_sugg = match *local_decl.local_info() {
+        let (amp_mut_sugg, local_var_ty_info) = match *local_decl.local_info() {
             LocalInfo::User(mir::BindingForm::ImplicitSelf(_)) => {
                 let (span, suggestion) = suggest_ampmut_self(self.infcx.tcx, decl_span);
                 let additional = local_trait.map(|span| suggest_ampmut_self(self.infcx.tcx, span));
-                Some(AmpMutSugg { has_sugg: true, span, suggestion, additional })
+                (AmpMutSugg::Type { span, suggestion, additional }, None)
             }
 
             LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
@@ -1143,79 +1139,54 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 opt_ty_info,
                 ..
             })) => {
-                // check if the RHS is from desugaring
+                // Check if the RHS is from desugaring.
+                let first_assignment = find_assignments(&self.body, local).first().copied();
+                let first_assignment_stmt = first_assignment
+                    .and_then(|loc| self.body[loc.block].statements.get(loc.statement_index));
+                trace!(?first_assignment_stmt);
                 let opt_assignment_rhs_span =
-                    self.find_assignments(local).first().map(|&location| {
-                        if let Some(mir::Statement {
-                            source_info: _,
-                            kind:
-                                mir::StatementKind::Assign(box (
-                                    _,
-                                    mir::Rvalue::Use(mir::Operand::Copy(place)),
-                                )),
-                            ..
-                        }) = self.body[location.block].statements.get(location.statement_index)
-                        {
-                            self.body.local_decls[place.local].source_info.span
-                        } else {
-                            self.body.source_info(location).span
-                        }
-                    });
-                match opt_assignment_rhs_span.and_then(|s| s.desugaring_kind()) {
-                    // on for loops, RHS points to the iterator part
-                    Some(DesugaringKind::ForLoop) => {
-                        let span = opt_assignment_rhs_span.unwrap();
-                        self.suggest_similar_mut_method_for_for_loop(err, span);
+                    first_assignment.map(|loc| self.body.source_info(loc).span);
+                let mut source_span = opt_assignment_rhs_span;
+                if let Some(mir::Statement {
+                    source_info: _,
+                    kind:
+                        mir::StatementKind::Assign(box (_, mir::Rvalue::Use(mir::Operand::Copy(place)))),
+                    ..
+                }) = first_assignment_stmt
+                {
+                    let local_span = self.body.local_decls[place.local].source_info.span;
+                    // `&self` in async functions have a `desugaring_kind`, but the local we assign
+                    // it with does not, so use the local_span for our checks later.
+                    source_span = Some(local_span);
+                    if let Some(DesugaringKind::ForLoop) = local_span.desugaring_kind() {
+                        // On for loops, RHS points to the iterator part.
+                        self.suggest_similar_mut_method_for_for_loop(err, local_span);
                         err.span_label(
-                            span,
+                            local_span,
                             format!("this iterator yields `{pointer_sigil}` {pointer_desc}s",),
                         );
-                        None
-                    }
-                    // don't create labels for compiler-generated spans
-                    Some(_) => None,
-                    // don't create labels for the span not from user's code
-                    None if opt_assignment_rhs_span
-                        .is_some_and(|span| self.infcx.tcx.sess.source_map().is_imported(span)) =>
-                    {
-                        None
-                    }
-                    None => {
-                        if name != kw::SelfLower {
-                            suggest_ampmut(
-                                self.infcx.tcx,
-                                local_decl.ty,
-                                decl_span,
-                                opt_assignment_rhs_span,
-                                opt_ty_info,
-                            )
-                        } else {
-                            match local_decl.local_info() {
-                                LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
-                                    opt_ty_info: None,
-                                    ..
-                                })) => {
-                                    let (span, sugg) =
-                                        suggest_ampmut_self(self.infcx.tcx, decl_span);
-                                    Some(AmpMutSugg {
-                                        has_sugg: true,
-                                        span,
-                                        suggestion: sugg,
-                                        additional: None,
-                                    })
-                                }
-                                // explicit self (eg `self: &'a Self`)
-                                _ => suggest_ampmut(
-                                    self.infcx.tcx,
-                                    local_decl.ty,
-                                    decl_span,
-                                    opt_assignment_rhs_span,
-                                    opt_ty_info,
-                                ),
-                            }
-                        }
+                        return;
                     }
                 }
+
+                // Don't create labels for compiler-generated spans or spans not from users' code.
+                if source_span.is_some_and(|s| {
+                    s.desugaring_kind().is_some() || self.infcx.tcx.sess.source_map().is_imported(s)
+                }) {
+                    return;
+                }
+
+                // This could be because we're in an `async fn`.
+                if name == kw::SelfLower && opt_ty_info.is_none() {
+                    let (span, suggestion) = suggest_ampmut_self(self.infcx.tcx, decl_span);
+                    (AmpMutSugg::Type { span, suggestion, additional: None }, None)
+                } else if let Some(sugg) =
+                    suggest_ampmut(self.infcx, self.body(), first_assignment_stmt)
+                {
+                    (sugg, opt_ty_info)
+                } else {
+                    return;
+                }
             }
 
             LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
@@ -1223,181 +1194,238 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 ..
             })) => {
                 let pattern_span: Span = local_decl.source_info.span;
-                suggest_ref_mut(self.infcx.tcx, pattern_span).map(|span| AmpMutSugg {
-                    has_sugg: true,
-                    span,
-                    suggestion: "mut ".to_owned(),
-                    additional: None,
-                })
+                let Some(span) = suggest_ref_mut(self.infcx.tcx, pattern_span) else {
+                    return;
+                };
+                (AmpMutSugg::Type { span, suggestion: "mut ".to_owned(), additional: None }, None)
             }
 
             _ => unreachable!(),
         };
 
-        match amp_mut_sugg {
-            Some(AmpMutSugg {
-                has_sugg: true,
-                span: err_help_span,
-                suggestion: suggested_code,
-                additional,
-            }) => {
-                let mut sugg = vec![(err_help_span, suggested_code)];
-                if let Some(s) = additional {
-                    sugg.push(s);
-                }
+        let mut suggest = |suggs: Vec<_>, applicability, extra| {
+            if suggs.iter().any(|(span, _)| self.infcx.tcx.sess.source_map().is_imported(*span)) {
+                return;
+            }
 
-                if sugg.iter().all(|(span, _)| !self.infcx.tcx.sess.source_map().is_imported(*span))
-                {
-                    err.multipart_suggestion_verbose(
-                        format!(
-                            "consider changing this to be a mutable {pointer_desc}{}",
-                            if is_trait_sig {
-                                " in the `impl` method and the `trait` definition"
-                            } else {
-                                ""
-                            }
-                        ),
-                        sugg,
-                        Applicability::MachineApplicable,
+            err.multipart_suggestion_verbose(
+                format!(
+                    "consider changing this to be a mutable {pointer_desc}{}{extra}",
+                    if is_trait_sig {
+                        " in the `impl` method and the `trait` definition"
+                    } else {
+                        ""
+                    }
+                ),
+                suggs,
+                applicability,
+            );
+        };
+
+        let (mut sugg, add_type_annotation_if_not_exists) = match amp_mut_sugg {
+            AmpMutSugg::Type { span, suggestion, additional } => {
+                let mut sugg = vec![(span, suggestion)];
+                sugg.extend(additional);
+                suggest(sugg, Applicability::MachineApplicable, "");
+                return;
+            }
+            AmpMutSugg::MapGetMut { span, suggestion } => {
+                if self.infcx.tcx.sess.source_map().is_imported(span) {
+                    return;
+                }
+                err.multipart_suggestion_verbose(
+                    "consider using `get_mut`",
+                    vec![(span, suggestion)],
+                    Applicability::MaybeIncorrect,
+                );
+                return;
+            }
+            AmpMutSugg::Expr { span, suggestion } => {
+                // `Expr` suggestions should change type annotations if they already exist (probably immut),
+                // but do not add new type annotations.
+                (vec![(span, suggestion)], false)
+            }
+            AmpMutSugg::ChangeBinding => (vec![], true),
+        };
+
+        // Find a binding's type to make mutable.
+        let (binding_exists, span) = match local_var_ty_info {
+            // If this is a variable binding with an explicit type,
+            // then we will suggest changing it to be mutable.
+            // This is `Applicability::MachineApplicable`.
+            Some(ty_span) => (true, ty_span),
+
+            // Otherwise, we'll suggest *adding* an annotated type, we'll suggest
+            // the RHS's type for that.
+            // This is `Applicability::HasPlaceholders`.
+            None => (false, decl_span),
+        };
+
+        if !binding_exists && !add_type_annotation_if_not_exists {
+            suggest(sugg, Applicability::MachineApplicable, "");
+            return;
+        }
+
+        // If the binding already exists and is a reference with an explicit
+        // lifetime, then we can suggest adding ` mut`. This is special-cased from
+        // the path without an explicit lifetime.
+        let (sugg_span, sugg_str, suggest_now) = if let Ok(src) = self.infcx.tcx.sess.source_map().span_to_snippet(span)
+            && src.starts_with("&'")
+            // Note that `&' a T` is invalid so this is correct.
+            && let Some(ws_pos) = src.find(char::is_whitespace)
+        {
+            let span = span.with_lo(span.lo() + BytePos(ws_pos as u32)).shrink_to_lo();
+            (span, " mut".to_owned(), true)
+        // If there is already a binding, we modify it to be `mut`.
+        } else if binding_exists {
+            // Shrink the span to just after the `&` in `&variable`.
+            let span = span.with_lo(span.lo() + BytePos(1)).shrink_to_lo();
+            (span, "mut ".to_owned(), true)
+        } else {
+            // Otherwise, suggest that the user annotates the binding; We provide the
+            // type of the local.
+            let ty = local_decl.ty.builtin_deref(true).unwrap();
+
+            (span, format!("{}mut {}", if local_decl.ty.is_ref() { "&" } else { "*" }, ty), false)
+        };
+
+        if suggest_now {
+            // Suggest changing `&x` to `&mut x` and changing `&T` to `&mut T` at the same time.
+            let has_change = !sugg.is_empty();
+            sugg.push((sugg_span, sugg_str));
+            suggest(
+                sugg,
+                Applicability::MachineApplicable,
+                // FIXME(fee1-dead) this somehow doesn't fire
+                if has_change { " and changing the binding's type" } else { "" },
+            );
+            return;
+        } else if !sugg.is_empty() {
+            suggest(sugg, Applicability::MachineApplicable, "");
+            return;
+        }
+
+        let def_id = self.body.source.def_id();
+        let hir_id = if let Some(local_def_id) = def_id.as_local()
+            && let Some(body) = self.infcx.tcx.hir_maybe_body_owned_by(local_def_id)
+        {
+            BindingFinder { span: sugg_span }.visit_body(&body).break_value()
+        } else {
+            None
+        };
+        let node = hir_id.map(|hir_id| self.infcx.tcx.hir_node(hir_id));
+
+        let Some(hir::Node::LetStmt(local)) = node else {
+            err.span_label(
+                sugg_span,
+                format!("consider changing this binding's type to be: `{sugg_str}`"),
+            );
+            return;
+        };
+
+        let tables = self.infcx.tcx.typeck(def_id.as_local().unwrap());
+        if let Some(clone_trait) = self.infcx.tcx.lang_items().clone_trait()
+            && let Some(expr) = local.init
+            && let ty = tables.node_type_opt(expr.hir_id)
+            && let Some(ty) = ty
+            && let ty::Ref(..) = ty.kind()
+        {
+            match self
+                .infcx
+                .type_implements_trait_shallow(clone_trait, ty.peel_refs(), self.infcx.param_env)
+                .as_deref()
+            {
+                Some([]) => {
+                    // FIXME: This error message isn't useful, since we're just
+                    // vaguely suggesting to clone a value that already
+                    // implements `Clone`.
+                    //
+                    // A correct suggestion here would take into account the fact
+                    // that inference may be affected by missing types on bindings,
+                    // etc., to improve "tests/ui/borrowck/issue-91206.stderr", for
+                    // example.
+                }
+                None => {
+                    if let hir::ExprKind::MethodCall(segment, _rcvr, [], span) = expr.kind
+                        && segment.ident.name == sym::clone
+                    {
+                        err.span_help(
+                            span,
+                            format!(
+                                "`{}` doesn't implement `Clone`, so this call clones \
+                                             the reference `{ty}`",
+                                ty.peel_refs(),
+                            ),
+                        );
+                    }
+                    // The type doesn't implement Clone.
+                    let trait_ref = ty::Binder::dummy(ty::TraitRef::new(
+                        self.infcx.tcx,
+                        clone_trait,
+                        [ty.peel_refs()],
+                    ));
+                    let obligation = traits::Obligation::new(
+                        self.infcx.tcx,
+                        traits::ObligationCause::dummy(),
+                        self.infcx.param_env,
+                        trait_ref,
+                    );
+                    self.infcx.err_ctxt().suggest_derive(
+                        &obligation,
+                        err,
+                        trait_ref.upcast(self.infcx.tcx),
                     );
                 }
-            }
-            Some(AmpMutSugg {
-                has_sugg: false, span: err_label_span, suggestion: message, ..
-            }) => {
-                let def_id = self.body.source.def_id();
-                let hir_id = if let Some(local_def_id) = def_id.as_local()
-                    && let Some(body) = self.infcx.tcx.hir_maybe_body_owned_by(local_def_id)
-                {
-                    BindingFinder { span: err_label_span }.visit_body(&body).break_value()
-                } else {
-                    None
-                };
-
-                if let Some(hir_id) = hir_id
-                    && let hir::Node::LetStmt(local) = self.infcx.tcx.hir_node(hir_id)
-                {
-                    let tables = self.infcx.tcx.typeck(def_id.as_local().unwrap());
-                    if let Some(clone_trait) = self.infcx.tcx.lang_items().clone_trait()
-                        && let Some(expr) = local.init
-                        && let ty = tables.node_type_opt(expr.hir_id)
-                        && let Some(ty) = ty
-                        && let ty::Ref(..) = ty.kind()
+                Some(errors) => {
+                    if let hir::ExprKind::MethodCall(segment, _rcvr, [], span) = expr.kind
+                        && segment.ident.name == sym::clone
                     {
-                        match self
-                            .infcx
-                            .type_implements_trait_shallow(
-                                clone_trait,
-                                ty.peel_refs(),
-                                self.infcx.param_env,
-                            )
-                            .as_deref()
-                        {
-                            Some([]) => {
-                                // FIXME: This error message isn't useful, since we're just
-                                // vaguely suggesting to clone a value that already
-                                // implements `Clone`.
-                                //
-                                // A correct suggestion here would take into account the fact
-                                // that inference may be affected by missing types on bindings,
-                                // etc., to improve "tests/ui/borrowck/issue-91206.stderr", for
-                                // example.
-                            }
-                            None => {
-                                if let hir::ExprKind::MethodCall(segment, _rcvr, [], span) =
-                                    expr.kind
-                                    && segment.ident.name == sym::clone
-                                {
-                                    err.span_help(
-                                        span,
-                                        format!(
-                                            "`{}` doesn't implement `Clone`, so this call clones \
-                                             the reference `{ty}`",
-                                            ty.peel_refs(),
-                                        ),
-                                    );
-                                }
-                                // The type doesn't implement Clone.
-                                let trait_ref = ty::Binder::dummy(ty::TraitRef::new(
-                                    self.infcx.tcx,
-                                    clone_trait,
-                                    [ty.peel_refs()],
-                                ));
-                                let obligation = traits::Obligation::new(
-                                    self.infcx.tcx,
-                                    traits::ObligationCause::dummy(),
-                                    self.infcx.param_env,
-                                    trait_ref,
-                                );
-                                self.infcx.err_ctxt().suggest_derive(
-                                    &obligation,
-                                    err,
-                                    trait_ref.upcast(self.infcx.tcx),
-                                );
-                            }
-                            Some(errors) => {
-                                if let hir::ExprKind::MethodCall(segment, _rcvr, [], span) =
-                                    expr.kind
-                                    && segment.ident.name == sym::clone
-                                {
-                                    err.span_help(
-                                        span,
-                                        format!(
-                                            "`{}` doesn't implement `Clone` because its \
+                        err.span_help(
+                            span,
+                            format!(
+                                "`{}` doesn't implement `Clone` because its \
                                              implementations trait bounds could not be met, so \
                                              this call clones the reference `{ty}`",
-                                            ty.peel_refs(),
-                                        ),
-                                    );
-                                    err.note(format!(
-                                        "the following trait bounds weren't met: {}",
-                                        errors
-                                            .iter()
-                                            .map(|e| e.obligation.predicate.to_string())
-                                            .collect::<Vec<_>>()
-                                            .join("\n"),
-                                    ));
-                                }
-                                // The type doesn't implement Clone because of unmet obligations.
-                                for error in errors {
-                                    if let traits::FulfillmentErrorCode::Select(
-                                        traits::SelectionError::Unimplemented,
-                                    ) = error.code
-                                        && let ty::PredicateKind::Clause(ty::ClauseKind::Trait(
-                                            pred,
-                                        )) = error.obligation.predicate.kind().skip_binder()
-                                    {
-                                        self.infcx.err_ctxt().suggest_derive(
-                                            &error.obligation,
-                                            err,
-                                            error.obligation.predicate.kind().rebind(pred),
-                                        );
-                                    }
-                                }
-                            }
+                                ty.peel_refs(),
+                            ),
+                        );
+                        err.note(format!(
+                            "the following trait bounds weren't met: {}",
+                            errors
+                                .iter()
+                                .map(|e| e.obligation.predicate.to_string())
+                                .collect::<Vec<_>>()
+                                .join("\n"),
+                        ));
+                    }
+                    // The type doesn't implement Clone because of unmet obligations.
+                    for error in errors {
+                        if let traits::FulfillmentErrorCode::Select(
+                            traits::SelectionError::Unimplemented,
+                        ) = error.code
+                            && let ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) =
+                                error.obligation.predicate.kind().skip_binder()
+                        {
+                            self.infcx.err_ctxt().suggest_derive(
+                                &error.obligation,
+                                err,
+                                error.obligation.predicate.kind().rebind(pred),
+                            );
                         }
                     }
-                    let (changing, span, sugg) = match local.ty {
-                        Some(ty) => ("changing", ty.span, message),
-                        None => {
-                            ("specifying", local.pat.span.shrink_to_hi(), format!(": {message}"))
-                        }
-                    };
-                    err.span_suggestion_verbose(
-                        span,
-                        format!("consider {changing} this binding's type"),
-                        sugg,
-                        Applicability::HasPlaceholders,
-                    );
-                } else {
-                    err.span_label(
-                        err_label_span,
-                        format!("consider changing this binding's type to be: `{message}`"),
-                    );
                 }
             }
-            None => {}
         }
+        let (changing, span, sugg) = match local.ty {
+            Some(ty) => ("changing", ty.span, sugg_str),
+            None => ("specifying", local.pat.span.shrink_to_hi(), format!(": {sugg_str}")),
+        };
+        err.span_suggestion_verbose(
+            span,
+            format!("consider {changing} this binding's type"),
+            sugg,
+            Applicability::HasPlaceholders,
+        );
     }
 }
 
@@ -1464,11 +1492,25 @@ fn suggest_ampmut_self(tcx: TyCtxt<'_>, span: Span) -> (Span, String) {
     }
 }
 
-struct AmpMutSugg {
-    has_sugg: bool,
-    span: Span,
-    suggestion: String,
-    additional: Option<(Span, String)>,
+enum AmpMutSugg {
+    /// Type suggestion. Changes `&self` to `&mut self`, `x: &T` to `x: &mut T`,
+    /// `ref x` to `ref mut x`, etc.
+    Type {
+        span: Span,
+        suggestion: String,
+        additional: Option<(Span, String)>,
+    },
+    /// Suggestion for expressions, `&x` to `&mut x`, `&x[i]` to `&mut x[i]`, etc.
+    Expr {
+        span: Span,
+        suggestion: String,
+    },
+    /// Suggests `.get_mut` in the case of `&map[&key]` for Hash/BTreeMap.
+    MapGetMut {
+        span: Span,
+        suggestion: String,
+    },
+    ChangeBinding,
 }
 
 // When we want to suggest a user change a local variable to be a `&mut`, there
@@ -1487,110 +1529,111 @@ struct AmpMutSugg {
 // This implementation attempts to emulate AST-borrowck prioritization
 // by trying (3.), then (2.) and finally falling back on (1.).
 fn suggest_ampmut<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    decl_ty: Ty<'tcx>,
-    decl_span: Span,
-    opt_assignment_rhs_span: Option<Span>,
-    opt_ty_info: Option<Span>,
+    infcx: &crate::BorrowckInferCtxt<'tcx>,
+    body: &Body<'tcx>,
+    opt_assignment_rhs_stmt: Option<&Statement<'tcx>>,
 ) -> Option<AmpMutSugg> {
-    // if there is a RHS and it starts with a `&` from it, then check if it is
+    let tcx = infcx.tcx;
+    // If there is a RHS and it starts with a `&` from it, then check if it is
     // mutable, and if not, put suggest putting `mut ` to make it mutable.
-    // we don't have to worry about lifetime annotations here because they are
+    // We don't have to worry about lifetime annotations here because they are
     // not valid when taking a reference. For example, the following is not valid Rust:
     //
     // let x: &i32 = &'a 5;
     //                ^^ lifetime annotation not allowed
     //
-    if let Some(rhs_span) = opt_assignment_rhs_span
-        && let Ok(rhs_str) = tcx.sess.source_map().span_to_snippet(rhs_span)
-        && let Some(rhs_str_no_amp) = rhs_str.strip_prefix('&')
+    if let Some(rhs_stmt) = opt_assignment_rhs_stmt
+        && let StatementKind::Assign(box (lhs, rvalue)) = &rhs_stmt.kind
+        && let mut rhs_span = rhs_stmt.source_info.span
+        && let Ok(mut rhs_str) = tcx.sess.source_map().span_to_snippet(rhs_span)
     {
-        // Suggest changing `&raw const` to `&raw mut` if applicable.
-        if rhs_str_no_amp.trim_start().strip_prefix("raw const").is_some() {
-            let const_idx = rhs_str.find("const").unwrap() as u32;
-            let const_span = rhs_span
-                .with_lo(rhs_span.lo() + BytePos(const_idx))
-                .with_hi(rhs_span.lo() + BytePos(const_idx + "const".len() as u32));
+        let mut rvalue = rvalue;
 
-            return Some(AmpMutSugg {
-                has_sugg: true,
-                span: const_span,
-                suggestion: "mut".to_owned(),
-                additional: None,
-            });
-        }
-
-        // Figure out if rhs already is `&mut`.
-        let is_mut = if let Some(rest) = rhs_str_no_amp.trim_start().strip_prefix("mut") {
-            match rest.chars().next() {
-                // e.g. `&mut x`
-                Some(c) if c.is_whitespace() => true,
-                // e.g. `&mut(x)`
-                Some('(') => true,
-                // e.g. `&mut{x}`
-                Some('{') => true,
-                // e.g. `&mutablevar`
-                _ => false,
+        // Take some special care when handling `let _x = &*_y`:
+        // We want to know if this is part of an overloaded index, so `let x = &a[0]`,
+        // or whether this is a usertype ascription (`let _x: &T = y`).
+        if let Rvalue::Ref(_, BorrowKind::Shared, place) = rvalue
+            && place.projection.len() == 1
+            && place.projection[0] == ProjectionElem::Deref
+            && let Some(assign) = find_assignments(&body, place.local).first()
+        {
+            // If this is a usertype ascription (`let _x: &T = _y`) then pierce through it as either we want
+            // to suggest `&mut` on the expression (handled here) or we return `None` and let the caller
+            // suggest `&mut` on the type if the expression seems fine (e.g. `let _x: &T = &mut _y`).
+            if let Some(user_ty_projs) = body.local_decls[lhs.local].user_ty.as_ref()
+                && let [user_ty_proj] = user_ty_projs.contents.as_slice()
+                && user_ty_proj.projs.is_empty()
+                && let Either::Left(rhs_stmt_new) = body.stmt_at(*assign)
+                && let StatementKind::Assign(box (_, rvalue_new)) = &rhs_stmt_new.kind
+                && let rhs_span_new = rhs_stmt_new.source_info.span
+                && let Ok(rhs_str_new) = tcx.sess.source_map().span_to_snippet(rhs_span)
+            {
+                (rvalue, rhs_span, rhs_str) = (rvalue_new, rhs_span_new, rhs_str_new);
             }
-        } else {
-            false
-        };
-        // if the reference is already mutable then there is nothing we can do
-        // here.
-        if !is_mut {
-            // shrink the span to just after the `&` in `&variable`
-            let span = rhs_span.with_lo(rhs_span.lo() + BytePos(1)).shrink_to_lo();
 
-            // FIXME(Ezrashaw): returning is bad because we still might want to
-            // update the annotated type, see #106857.
-            return Some(AmpMutSugg {
-                has_sugg: true,
-                span,
-                suggestion: "mut ".to_owned(),
-                additional: None,
-            });
+            if let Either::Right(call) = body.stmt_at(*assign)
+                && let TerminatorKind::Call {
+                    func: Operand::Constant(box const_operand), args, ..
+                } = &call.kind
+                && let ty::FnDef(method_def_id, method_args) = *const_operand.ty().kind()
+                && let Some(trait_) = tcx.trait_of_assoc(method_def_id)
+                && tcx.is_lang_item(trait_, hir::LangItem::Index)
+            {
+                let trait_ref = ty::TraitRef::from_assoc(
+                    tcx,
+                    tcx.require_lang_item(hir::LangItem::IndexMut, rhs_span),
+                    method_args,
+                );
+                // The type only implements `Index` but not `IndexMut`, we must not suggest `&mut`.
+                if !infcx
+                    .type_implements_trait(trait_ref.def_id, trait_ref.args, infcx.param_env)
+                    .must_apply_considering_regions()
+                {
+                    // Suggest `get_mut` if type is a `BTreeMap` or `HashMap`.
+                    if let ty::Adt(def, _) = trait_ref.self_ty().kind()
+                        && [sym::BTreeMap, sym::HashMap]
+                            .into_iter()
+                            .any(|s| tcx.is_diagnostic_item(s, def.did()))
+                        && let [map, key] = &**args
+                        && let Ok(map) = tcx.sess.source_map().span_to_snippet(map.span)
+                        && let Ok(key) = tcx.sess.source_map().span_to_snippet(key.span)
+                    {
+                        let span = rhs_span;
+                        let suggestion = format!("{map}.get_mut({key}).unwrap()");
+                        return Some(AmpMutSugg::MapGetMut { span, suggestion });
+                    }
+                    return None;
+                }
+            }
+        }
+
+        let sugg = match rvalue {
+            Rvalue::Ref(_, BorrowKind::Shared, _) if let Some(ref_idx) = rhs_str.find('&') => {
+                // Shrink the span to just after the `&` in `&variable`.
+                Some((
+                    rhs_span.with_lo(rhs_span.lo() + BytePos(ref_idx as u32 + 1)).shrink_to_lo(),
+                    "mut ".to_owned(),
+                ))
+            }
+            Rvalue::RawPtr(RawPtrKind::Const, _) if let Some(const_idx) = rhs_str.find("const") => {
+                // Suggest changing `&raw const` to `&raw mut` if applicable.
+                let const_idx = const_idx as u32;
+                Some((
+                    rhs_span
+                        .with_lo(rhs_span.lo() + BytePos(const_idx))
+                        .with_hi(rhs_span.lo() + BytePos(const_idx + "const".len() as u32)),
+                    "mut".to_owned(),
+                ))
+            }
+            _ => None,
+        };
+
+        if let Some((span, suggestion)) = sugg {
+            return Some(AmpMutSugg::Expr { span, suggestion });
         }
     }
 
-    let (binding_exists, span) = match opt_ty_info {
-        // if this is a variable binding with an explicit type,
-        // then we will suggest changing it to be mutable.
-        // this is `Applicability::MachineApplicable`.
-        Some(ty_span) => (true, ty_span),
-
-        // otherwise, we'll suggest *adding* an annotated type, we'll suggest
-        // the RHS's type for that.
-        // this is `Applicability::HasPlaceholders`.
-        None => (false, decl_span),
-    };
-
-    // if the binding already exists and is a reference with an explicit
-    // lifetime, then we can suggest adding ` mut`. this is special-cased from
-    // the path without an explicit lifetime.
-    if let Ok(src) = tcx.sess.source_map().span_to_snippet(span)
-        && src.starts_with("&'")
-        // note that `&     'a T` is invalid so this is correct.
-        && let Some(ws_pos) = src.find(char::is_whitespace)
-    {
-        let span = span.with_lo(span.lo() + BytePos(ws_pos as u32)).shrink_to_lo();
-        Some(AmpMutSugg { has_sugg: true, span, suggestion: " mut".to_owned(), additional: None })
-    // if there is already a binding, we modify it to be `mut`
-    } else if binding_exists {
-        // shrink the span to just after the `&` in `&variable`
-        let span = span.with_lo(span.lo() + BytePos(1)).shrink_to_lo();
-        Some(AmpMutSugg { has_sugg: true, span, suggestion: "mut ".to_owned(), additional: None })
-    } else {
-        // otherwise, suggest that the user annotates the binding; we provide the
-        // type of the local.
-        let ty = decl_ty.builtin_deref(true).unwrap();
-
-        Some(AmpMutSugg {
-            has_sugg: false,
-            span,
-            suggestion: format!("{}mut {}", if decl_ty.is_ref() { "&" } else { "*" }, ty),
-            additional: None,
-        })
-    }
+    Some(AmpMutSugg::ChangeBinding)
 }
 
 /// If the type is a `Coroutine`, `Closure`, or `CoroutineClosure`

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -215,7 +215,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         diag: &mut Diag<'_>,
         lower_bound: RegionVid,
     ) {
-        let mut suggestions = vec![];
         let tcx = self.infcx.tcx;
 
         // find generic associated types in the given region 'lower_bound'
@@ -237,9 +236,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             .collect::<Vec<_>>();
         debug!(?gat_id_and_generics);
 
-        // find higher-ranked trait bounds bounded to the generic associated types
+        // Look for the where-bound which introduces the placeholder.
+        // As we're using the HIR, we need to handle both `for<'a> T: Trait<'a>`
+        // and `T: for<'a> Trait`<'a>.
         let mut hrtb_bounds = vec![];
-        gat_id_and_generics.iter().flatten().for_each(|(gat_hir_id, generics)| {
+        gat_id_and_generics.iter().flatten().for_each(|&(gat_hir_id, generics)| {
             for pred in generics.predicates {
                 let BoundPredicate(WhereBoundPredicate { bound_generic_params, bounds, .. }) =
                     pred.kind
@@ -248,17 +249,32 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 };
                 if bound_generic_params
                     .iter()
-                    .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == *gat_hir_id)
+                    .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == gat_hir_id)
                     .is_some()
                 {
                     for bound in *bounds {
                         hrtb_bounds.push(bound);
                     }
+                } else {
+                    for bound in *bounds {
+                        if let Trait(trait_bound) = bound {
+                            if trait_bound
+                                .bound_generic_params
+                                .iter()
+                                .rfind(|bgp| tcx.local_def_id_to_hir_id(bgp.def_id) == gat_hir_id)
+                                .is_some()
+                            {
+                                hrtb_bounds.push(bound);
+                                return;
+                            }
+                        }
+                    }
                 }
             }
         });
         debug!(?hrtb_bounds);
 
+        let mut suggestions = vec![];
         hrtb_bounds.iter().for_each(|bound| {
             let Trait(PolyTraitRef { trait_ref, span: trait_span, .. }) = bound else {
                 return;

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -124,8 +124,13 @@ impl<'a, 'b, 'tcx> NllTypeRelating<'a, 'b, 'tcx> {
         // by using `ty_vid rel B` and then finally and end by equating `ty_vid` to
         // the opaque.
         let mut enable_subtyping = |ty, opaque_is_expected| {
-            let ty_vid = infcx.next_ty_var_id_in_universe(self.span(), ty::UniverseIndex::ROOT);
-
+            // We create the fresh inference variable in the highest universe.
+            // In theory we could limit it to the highest universe in the args of
+            // the opaque but that isn't really worth the effort.
+            //
+            // We'll make sure that the opaque type can actually name everything
+            // in its hidden type later on.
+            let ty_vid = infcx.next_ty_vid(self.span());
             let variance = if opaque_is_expected {
                 self.ambient_variance
             } else {

compiler/rustc_builtin_macros/src/deriving/from.rs

@@ -27,21 +27,39 @@ pub(crate) fn expand_deriving_from(
         cx.dcx().bug("derive(From) used on something else than an item");
     };
 
-    // #[derive(From)] is currently usable only on structs with exactly one field.
-    let field = if let ItemKind::Struct(_, _, data) = &item.kind
-        && let [field] = data.fields()
-    {
-        Some(field.clone())
-    } else {
-        None
+    let err_span = || {
+        let item_span = item.kind.ident().map(|ident| ident.span).unwrap_or(item.span);
+        MultiSpan::from_spans(vec![span, item_span])
     };
 
-    let from_type = match &field {
-        Some(field) => Ty::AstTy(field.ty.clone()),
-        // We don't have a type to put into From<...> if we don't have a single field, so just put
-        // unit there.
-        None => Ty::Unit,
+    // `#[derive(From)]` is currently usable only on structs with exactly one field.
+    let field = match &item.kind {
+        ItemKind::Struct(_, _, data) => {
+            if let [field] = data.fields() {
+                Ok(field.clone())
+            } else {
+                let guar = cx.dcx().emit_err(errors::DeriveFromWrongFieldCount {
+                    span: err_span(),
+                    multiple_fields: data.fields().len() > 1,
+                });
+                Err(guar)
+            }
+        }
+        ItemKind::Enum(_, _, _) | ItemKind::Union(_, _, _) => {
+            let guar = cx.dcx().emit_err(errors::DeriveFromWrongTarget {
+                span: err_span(),
+                kind: &format!("{} {}", item.kind.article(), item.kind.descr()),
+            });
+            Err(guar)
+        }
+        _ => cx.dcx().bug("Invalid derive(From) ADT input"),
     };
+
+    let from_type = Ty::AstTy(match field {
+        Ok(ref field) => field.ty.clone(),
+        Err(guar) => cx.ty(span, ast::TyKind::Err(guar)),
+    });
+
     let path =
         Path::new_(pathvec_std!(convert::From), vec![Box::new(from_type.clone())], PathKind::Std);
 
@@ -71,34 +89,17 @@ pub(crate) fn expand_deriving_from(
             attributes: thin_vec![cx.attr_word(sym::inline, span)],
             fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
             combine_substructure: combine_substructure(Box::new(|cx, span, substructure| {
-                let Some(field) = &field else {
-                    let item_span = item.kind.ident().map(|ident| ident.span).unwrap_or(item.span);
-                    let err_span = MultiSpan::from_spans(vec![span, item_span]);
-                    let error = match &item.kind {
-                        ItemKind::Struct(_, _, data) => {
-                            cx.dcx().emit_err(errors::DeriveFromWrongFieldCount {
-                                span: err_span,
-                                multiple_fields: data.fields().len() > 1,
-                            })
-                        }
-                        ItemKind::Enum(_, _, _) | ItemKind::Union(_, _, _) => {
-                            cx.dcx().emit_err(errors::DeriveFromWrongTarget {
-                                span: err_span,
-                                kind: &format!("{} {}", item.kind.article(), item.kind.descr()),
-                            })
-                        }
-                        _ => cx.dcx().bug("Invalid derive(From) ADT input"),
-                    };
-
-                    return BlockOrExpr::new_expr(DummyResult::raw_expr(span, Some(error)));
+                let field = match field {
+                    Ok(ref field) => field,
+                    Err(guar) => {
+                        return BlockOrExpr::new_expr(DummyResult::raw_expr(span, Some(guar)));
+                    }
                 };
 
                 let self_kw = Ident::new(kw::SelfUpper, span);
                 let expr: Box<ast::Expr> = match substructure.fields {
                     SubstructureFields::StaticStruct(variant, _) => match variant {
-                        // Self {
-                        //     field: value
-                        // }
+                        // Self { field: value }
                         VariantData::Struct { .. } => cx.expr_struct_ident(
                             span,
                             self_kw,

compiler/rustc_builtin_macros/src/lib.rs

@@ -8,7 +8,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
-#![feature(autodiff)]
 #![feature(box_patterns)]
 #![feature(decl_macro)]
 #![feature(if_let_guard)]

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -497,7 +497,7 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
             to_add.push(llvm::CreateAttrStringValue(cx.llcx, "wasm-import-module", module));
 
             let name =
-                codegen_fn_attrs.link_name.unwrap_or_else(|| cx.tcx.item_name(instance.def_id()));
+                codegen_fn_attrs.symbol_name.unwrap_or_else(|| cx.tcx.item_name(instance.def_id()));
             let name = name.as_str();
             to_add.push(llvm::CreateAttrStringValue(cx.llcx, "wasm-import-name", name));
         }

compiler/rustc_codegen_llvm/src/back/archive.rs

@@ -1,104 +1,21 @@
 //! A helper class for dealing with static archives
 
-use std::ffi::{CStr, CString, c_char, c_void};
-use std::path::{Path, PathBuf};
-use std::{io, mem, ptr, str};
+use std::ffi::{CStr, c_char, c_void};
+use std::io;
 
 use rustc_codegen_ssa::back::archive::{
-    ArArchiveBuilder, ArchiveBuildFailure, ArchiveBuilder, ArchiveBuilderBuilder,
-    DEFAULT_OBJECT_READER, ObjectReader, UnknownArchiveKind, try_extract_macho_fat_archive,
+    ArArchiveBuilder, ArchiveBuilder, ArchiveBuilderBuilder, DEFAULT_OBJECT_READER, ObjectReader,
 };
 use rustc_session::Session;
 
-use crate::llvm::archive_ro::{ArchiveRO, Child};
-use crate::llvm::{self, ArchiveKind, last_error};
-
-/// Helper for adding many files to an archive.
-#[must_use = "must call build() to finish building the archive"]
-pub(crate) struct LlvmArchiveBuilder<'a> {
-    sess: &'a Session,
-    additions: Vec<Addition>,
-}
-
-enum Addition {
-    File { path: PathBuf, name_in_archive: String },
-    Archive { path: PathBuf, archive: ArchiveRO, skip: Box<dyn FnMut(&str) -> bool> },
-}
-
-impl Addition {
-    fn path(&self) -> &Path {
-        match self {
-            Addition::File { path, .. } | Addition::Archive { path, .. } => path,
-        }
-    }
-}
-
-fn is_relevant_child(c: &Child<'_>) -> bool {
-    match c.name() {
-        Some(name) => !name.contains("SYMDEF"),
-        None => false,
-    }
-}
-
-impl<'a> ArchiveBuilder for LlvmArchiveBuilder<'a> {
-    fn add_archive(
-        &mut self,
-        archive: &Path,
-        skip: Box<dyn FnMut(&str) -> bool + 'static>,
-    ) -> io::Result<()> {
-        let mut archive = archive.to_path_buf();
-        if self.sess.target.llvm_target.contains("-apple-macosx") {
-            if let Some(new_archive) = try_extract_macho_fat_archive(self.sess, &archive)? {
-                archive = new_archive
-            }
-        }
-        let archive_ro = match ArchiveRO::open(&archive) {
-            Ok(ar) => ar,
-            Err(e) => return Err(io::Error::new(io::ErrorKind::Other, e)),
-        };
-        if self.additions.iter().any(|ar| ar.path() == archive) {
-            return Ok(());
-        }
-        self.additions.push(Addition::Archive {
-            path: archive,
-            archive: archive_ro,
-            skip: Box::new(skip),
-        });
-        Ok(())
-    }
-
-    /// Adds an arbitrary file to this archive
-    fn add_file(&mut self, file: &Path) {
-        let name = file.file_name().unwrap().to_str().unwrap();
-        self.additions
-            .push(Addition::File { path: file.to_path_buf(), name_in_archive: name.to_owned() });
-    }
-
-    /// Combine the provided files, rlibs, and native libraries into a single
-    /// `Archive`.
-    fn build(mut self: Box<Self>, output: &Path) -> bool {
-        match self.build_with_llvm(output) {
-            Ok(any_members) => any_members,
-            Err(error) => {
-                self.sess.dcx().emit_fatal(ArchiveBuildFailure { path: output.to_owned(), error })
-            }
-        }
-    }
-}
+use crate::llvm;
 
 pub(crate) struct LlvmArchiveBuilderBuilder;
 
 impl ArchiveBuilderBuilder for LlvmArchiveBuilderBuilder {
     fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder + 'a> {
-        // Keeping LlvmArchiveBuilder around in case of a regression caused by using
-        // ArArchiveBuilder.
-        // FIXME(#128955) remove a couple of months after #128936 gets merged in case
-        // no regression is found.
-        if false {
-            Box::new(LlvmArchiveBuilder { sess, additions: Vec::new() })
-        } else {
-            Box::new(ArArchiveBuilder::new(sess, &LLVM_OBJECT_READER))
-        }
+        // Use the `object` crate to build archives, with a little bit of help from LLVM.
+        Box::new(ArArchiveBuilder::new(sess, &LLVM_OBJECT_READER))
     }
 }
 
@@ -178,91 +95,3 @@ fn llvm_is_64_bit_object_file(buf: &[u8]) -> bool {
 fn llvm_is_ec_object_file(buf: &[u8]) -> bool {
     unsafe { llvm::LLVMRustIsECObject(buf.as_ptr(), buf.len()) }
 }
-
-impl<'a> LlvmArchiveBuilder<'a> {
-    fn build_with_llvm(&mut self, output: &Path) -> io::Result<bool> {
-        let kind = &*self.sess.target.archive_format;
-        let kind = kind
-            .parse::<ArchiveKind>()
-            .map_err(|_| kind)
-            .unwrap_or_else(|kind| self.sess.dcx().emit_fatal(UnknownArchiveKind { kind }));
-
-        let mut additions = mem::take(&mut self.additions);
-        // Values in the `members` list below will contain pointers to the strings allocated here.
-        // So they need to get dropped after all elements of `members` get freed.
-        let mut strings = Vec::new();
-        let mut members = Vec::new();
-
-        let dst = CString::new(output.to_str().unwrap())?;
-
-        unsafe {
-            for addition in &mut additions {
-                match addition {
-                    Addition::File { path, name_in_archive } => {
-                        let path = CString::new(path.to_str().unwrap())?;
-                        let name = CString::new(name_in_archive.as_bytes())?;
-                        members.push(llvm::LLVMRustArchiveMemberNew(
-                            path.as_ptr(),
-                            name.as_ptr(),
-                            None,
-                        ));
-                        strings.push(path);
-                        strings.push(name);
-                    }
-                    Addition::Archive { archive, skip, .. } => {
-                        for child in archive.iter() {
-                            let child = child.map_err(string_to_io_error)?;
-                            if !is_relevant_child(&child) {
-                                continue;
-                            }
-                            let child_name = child.name().unwrap();
-                            if skip(child_name) {
-                                continue;
-                            }
-
-                            // It appears that LLVM's archive writer is a little
-                            // buggy if the name we pass down isn't just the
-                            // filename component, so chop that off here and
-                            // pass it in.
-                            //
-                            // See LLVM bug 25877 for more info.
-                            let child_name =
-                                Path::new(child_name).file_name().unwrap().to_str().unwrap();
-                            let name = CString::new(child_name)?;
-                            let m = llvm::LLVMRustArchiveMemberNew(
-                                ptr::null(),
-                                name.as_ptr(),
-                                Some(child.raw),
-                            );
-                            members.push(m);
-                            strings.push(name);
-                        }
-                    }
-                }
-            }
-
-            let r = llvm::LLVMRustWriteArchive(
-                dst.as_ptr(),
-                members.len() as libc::size_t,
-                members.as_ptr() as *const &_,
-                true,
-                kind,
-                self.sess.target.arch == "arm64ec",
-            );
-            let ret = if r.into_result().is_err() {
-                let msg = last_error().unwrap_or_else(|| "failed to write archive".into());
-                Err(io::Error::new(io::ErrorKind::Other, msg))
-            } else {
-                Ok(!members.is_empty())
-            };
-            for member in members {
-                llvm::LLVMRustArchiveMemberFree(member);
-            }
-            ret
-        }
-    }
-}
-
-fn string_to_io_error(s: String) -> io::Error {
-    io::Error::new(io::ErrorKind::Other, format!("bad archive: {s}"))
-}

compiler/rustc_codegen_llvm/src/back/mod.rs

@@ -0,0 +1,5 @@
+pub(crate) mod archive;
+pub(crate) mod lto;
+pub(crate) mod owned_target_machine;
+mod profiling;
+pub(crate) mod write;

compiler/rustc_codegen_llvm/src/back/owned_target_machine.rs

@@ -1,4 +1,5 @@
-use std::ffi::{CStr, c_char};
+use std::assert_matches::assert_matches;
+use std::ffi::CStr;
 use std::marker::PhantomData;
 use std::ptr::NonNull;
 
@@ -41,11 +42,9 @@ impl OwnedTargetMachine {
         args_cstr_buff: &[u8],
         use_wasm_eh: bool,
     ) -> Result<Self, LlvmError<'static>> {
-        assert!(args_cstr_buff.len() > 0);
-        assert!(
-            *args_cstr_buff.last().unwrap() == 0,
-            "The last character must be a null terminator."
-        );
+        // The argument list is passed as the concatenation of one or more C strings.
+        // This implies that there must be a last byte, and it must be 0.
+        assert_matches!(args_cstr_buff, [.., b'\0'], "the last byte must be a NUL terminator");
 
         // SAFETY: llvm::LLVMRustCreateTargetMachine copies pointed to data
         let tm_ptr = unsafe {
@@ -71,7 +70,7 @@ impl OwnedTargetMachine {
                 output_obj_file.as_ptr(),
                 debug_info_compression.as_ptr(),
                 use_emulated_tls,
-                args_cstr_buff.as_ptr() as *const c_char,
+                args_cstr_buff.as_ptr(),
                 args_cstr_buff.len(),
                 use_wasm_eh,
             )
@@ -99,7 +98,7 @@ impl Drop for OwnedTargetMachine {
         // llvm::LLVMRustCreateTargetMachine OwnedTargetMachine is not copyable so there is no
         // double free or use after free.
         unsafe {
-            llvm::LLVMRustDisposeTargetMachine(self.tm_unique.as_mut());
+            llvm::LLVMRustDisposeTargetMachine(self.tm_unique.as_ptr());
         }
     }
 }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -1453,7 +1453,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         instance: Option<Instance<'tcx>>,
     ) {
         let call = self.call(llty, fn_attrs, Some(fn_abi), llfn, args, funclet, instance);
-        llvm::LLVMRustSetTailCallKind(call, llvm::TailCallKind::MustTail);
+        llvm::LLVMSetTailCallKind(call, llvm::TailCallKind::MustTail);
 
         match &fn_abi.ret.mode {
             PassMode::Ignore | PassMode::Indirect { .. } => self.ret_void(),

compiler/rustc_codegen_llvm/src/context.rs

@@ -377,6 +377,15 @@ pub(crate) unsafe fn create_module<'ll>(
         }
     }
 
+    if let Some(regparm_count) = sess.opts.unstable_opts.regparm {
+        llvm::add_module_flag_u32(
+            llmod,
+            llvm::ModuleFlagMergeBehavior::Error,
+            "NumRegisterParameters",
+            regparm_count,
+        );
+    }
+
     if let Some(BranchProtection { bti, pac_ret }) = sess.opts.unstable_opts.branch_protection {
         if sess.target.arch == "aarch64" {
             llvm::add_module_flag_u32(
@@ -462,6 +471,15 @@ pub(crate) unsafe fn create_module<'ll>(
         }
     }
 
+    if sess.opts.unstable_opts.indirect_branch_cs_prefix {
+        llvm::add_module_flag_u32(
+            llmod,
+            llvm::ModuleFlagMergeBehavior::Override,
+            "indirect_branch_cs_prefix",
+            1,
+        );
+    }
+
     match (sess.opts.unstable_opts.small_data_threshold, sess.target.small_data_threshold_support())
     {
         // Set up the small-data optimization limit for architectures that use

compiler/rustc_codegen_llvm/src/lib.rs

@@ -46,18 +46,11 @@ use rustc_session::Session;
 use rustc_session::config::{OptLevel, OutputFilenames, PrintKind, PrintRequest};
 use rustc_span::Symbol;
 
-mod back {
-    pub(crate) mod archive;
-    pub(crate) mod lto;
-    pub(crate) mod owned_target_machine;
-    mod profiling;
-    pub(crate) mod write;
-}
-
 mod abi;
 mod allocator;
 mod asm;
 mod attributes;
+mod back;
 mod base;
 mod builder;
 mod callee;

compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs

@@ -1,94 +0,0 @@
-//! A wrapper around LLVM's archive (.a) code
-
-use std::path::Path;
-use std::{slice, str};
-
-use rustc_fs_util::path_to_c_string;
-
-pub(crate) struct ArchiveRO {
-    pub raw: &'static mut super::Archive,
-}
-
-unsafe impl Send for ArchiveRO {}
-
-pub(crate) struct Iter<'a> {
-    raw: &'a mut super::ArchiveIterator<'a>,
-}
-
-pub(crate) struct Child<'a> {
-    pub raw: &'a mut super::ArchiveChild<'a>,
-}
-
-impl ArchiveRO {
-    /// Opens a static archive for read-only purposes. This is more optimized
-    /// than the `open` method because it uses LLVM's internal `Archive` class
-    /// rather than shelling out to `ar` for everything.
-    ///
-    /// If this archive is used with a mutable method, then an error will be
-    /// raised.
-    pub(crate) fn open(dst: &Path) -> Result<ArchiveRO, String> {
-        unsafe {
-            let s = path_to_c_string(dst);
-            let ar = super::LLVMRustOpenArchive(s.as_ptr()).ok_or_else(|| {
-                super::last_error().unwrap_or_else(|| "failed to open archive".to_owned())
-            })?;
-            Ok(ArchiveRO { raw: ar })
-        }
-    }
-
-    pub(crate) fn iter(&self) -> Iter<'_> {
-        unsafe { Iter { raw: super::LLVMRustArchiveIteratorNew(self.raw) } }
-    }
-}
-
-impl Drop for ArchiveRO {
-    fn drop(&mut self) {
-        unsafe {
-            super::LLVMRustDestroyArchive(&mut *(self.raw as *mut _));
-        }
-    }
-}
-
-impl<'a> Iterator for Iter<'a> {
-    type Item = Result<Child<'a>, String>;
-
-    fn next(&mut self) -> Option<Result<Child<'a>, String>> {
-        unsafe {
-            match super::LLVMRustArchiveIteratorNext(self.raw) {
-                Some(raw) => Some(Ok(Child { raw })),
-                None => super::last_error().map(Err),
-            }
-        }
-    }
-}
-
-impl<'a> Drop for Iter<'a> {
-    fn drop(&mut self) {
-        unsafe {
-            super::LLVMRustArchiveIteratorFree(&mut *(self.raw as *mut _));
-        }
-    }
-}
-
-impl<'a> Child<'a> {
-    pub(crate) fn name(&self) -> Option<&'a str> {
-        unsafe {
-            let mut name_len = 0;
-            let name_ptr = super::LLVMRustArchiveChildName(self.raw, &mut name_len);
-            if name_ptr.is_null() {
-                None
-            } else {
-                let name = slice::from_raw_parts(name_ptr as *const u8, name_len as usize);
-                str::from_utf8(name).ok().map(|s| s.trim())
-            }
-        }
-    }
-}
-
-impl<'a> Drop for Child<'a> {
-    fn drop(&mut self) {
-        unsafe {
-            super::LLVMRustArchiveChildFree(&mut *(self.raw as *mut _));
-        }
-    }
-}

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -97,6 +97,7 @@ pub(crate) enum ModuleFlagMergeBehavior {
 
 // Consts for the LLVM CallConv type, pre-cast to usize.
 
+/// Must match the layout of `LLVMTailCallKind`.
 #[derive(Copy, Clone, PartialEq, Debug)]
 #[repr(C)]
 #[allow(dead_code)]
@@ -332,10 +333,15 @@ impl RealPredicate {
     }
 }
 
-/// LLVMTypeKind
-#[derive(Copy, Clone, PartialEq, Debug)]
+/// Must match the layout of `LLVMTypeKind`.
+///
+/// Use [`RawEnum<TypeKind>`] for values of `LLVMTypeKind` returned from LLVM,
+/// to avoid risk of UB if LLVM adds new enum values.
+///
+/// All of LLVM's variants should be declared here, even if no Rust-side code refers
+/// to them, because unknown variants will cause [`RawEnum::to_rust`] to panic.
+#[derive(Copy, Clone, PartialEq, Debug, TryFromU32)]
 #[repr(C)]
-#[expect(dead_code, reason = "Some variants are unused, but are kept to match LLVM-C")]
 pub(crate) enum TypeKind {
     Void = 0,
     Half = 1,
@@ -610,17 +616,6 @@ pub(crate) enum DiagnosticLevel {
     Remark,
 }
 
-/// LLVMRustArchiveKind
-#[derive(Copy, Clone)]
-#[repr(C)]
-pub(crate) enum ArchiveKind {
-    K_GNU,
-    K_BSD,
-    K_DARWIN,
-    K_COFF,
-    K_AIXBIG,
-}
-
 unsafe extern "C" {
     // LLVMRustThinLTOData
     pub(crate) type ThinLTOData;
@@ -769,19 +764,12 @@ pub(crate) struct Builder<'a>(InvariantOpaque<'a>);
 pub(crate) struct PassManager<'a>(InvariantOpaque<'a>);
 unsafe extern "C" {
     pub type TargetMachine;
-    pub(crate) type Archive;
 }
-#[repr(C)]
-pub(crate) struct ArchiveIterator<'a>(InvariantOpaque<'a>);
-#[repr(C)]
-pub(crate) struct ArchiveChild<'a>(InvariantOpaque<'a>);
 unsafe extern "C" {
     pub(crate) type Twine;
     pub(crate) type DiagnosticInfo;
     pub(crate) type SMDiagnostic;
 }
-#[repr(C)]
-pub(crate) struct RustArchiveMember<'a>(InvariantOpaque<'a>);
 /// Opaque pointee of `LLVMOperandBundleRef`.
 #[repr(C)]
 pub(crate) struct OperandBundle<'a>(InvariantOpaque<'a>);
@@ -1046,6 +1034,8 @@ unsafe extern "C" {
         CanThrow: llvm::Bool,
     ) -> &'ll Value;
 
+    pub(crate) safe fn LLVMGetTypeKind(Ty: &Type) -> RawEnum<TypeKind>;
+
     // Operations on integer types
     pub(crate) fn LLVMInt1TypeInContext(C: &Context) -> &Type;
     pub(crate) fn LLVMInt8TypeInContext(C: &Context) -> &Type;
@@ -1197,7 +1187,7 @@ unsafe extern "C" {
     pub(crate) safe fn LLVMIsGlobalConstant(GlobalVar: &Value) -> Bool;
     pub(crate) safe fn LLVMSetGlobalConstant(GlobalVar: &Value, IsConstant: Bool);
     pub(crate) safe fn LLVMSetTailCall(CallInst: &Value, IsTailCall: Bool);
-    pub(crate) safe fn LLVMRustSetTailCallKind(CallInst: &Value, Kind: TailCallKind);
+    pub(crate) safe fn LLVMSetTailCallKind(CallInst: &Value, kind: TailCallKind);
 
     // Operations on attributes
     pub(crate) fn LLVMCreateStringAttribute(
@@ -1841,9 +1831,6 @@ unsafe extern "C" {
     // Create and destroy contexts.
     pub(crate) fn LLVMRustContextCreate(shouldDiscardNames: bool) -> &'static mut Context;
 
-    /// See llvm::LLVMTypeKind::getTypeID.
-    pub(crate) fn LLVMRustGetTypeKind(Ty: &Type) -> TypeKind;
-
     // Operations on all values
     pub(crate) fn LLVMRustGlobalAddMetadata<'a>(
         Val: &'a Value,
@@ -2438,7 +2425,7 @@ unsafe extern "C" {
         OutputObjFile: *const c_char,
         DebugInfoCompression: *const c_char,
         UseEmulatedTls: bool,
-        ArgsCstrBuff: *const c_char,
+        ArgsCstrBuff: *const c_uchar, // See "PTR_LEN_STR".
         ArgsCstrBuffLen: usize,
         UseWasmEH: bool,
     ) -> *mut TargetMachine;
@@ -2505,19 +2492,6 @@ unsafe extern "C" {
     pub(crate) fn LLVMRustSetNormalizedTarget(M: &Module, triple: *const c_char);
     pub(crate) fn LLVMRustRunRestrictionPass(M: &Module, syms: *const *const c_char, len: size_t);
 
-    pub(crate) fn LLVMRustOpenArchive(path: *const c_char) -> Option<&'static mut Archive>;
-    pub(crate) fn LLVMRustArchiveIteratorNew(AR: &Archive) -> &mut ArchiveIterator<'_>;
-    pub(crate) fn LLVMRustArchiveIteratorNext<'a>(
-        AIR: &ArchiveIterator<'a>,
-    ) -> Option<&'a mut ArchiveChild<'a>>;
-    pub(crate) fn LLVMRustArchiveChildName(
-        ACR: &ArchiveChild<'_>,
-        size: &mut size_t,
-    ) -> *const c_char;
-    pub(crate) fn LLVMRustArchiveChildFree<'a>(ACR: &'a mut ArchiveChild<'a>);
-    pub(crate) fn LLVMRustArchiveIteratorFree<'a>(AIR: &'a mut ArchiveIterator<'a>);
-    pub(crate) fn LLVMRustDestroyArchive(AR: &'static mut Archive);
-
     pub(crate) fn LLVMRustWriteTwineToString(T: &Twine, s: &RustString);
 
     pub(crate) fn LLVMRustUnpackOptimizationDiagnostic<'a>(
@@ -2555,21 +2529,6 @@ unsafe extern "C" {
         num_ranges: &mut usize,
     ) -> bool;
 
-    pub(crate) fn LLVMRustWriteArchive(
-        Dst: *const c_char,
-        NumMembers: size_t,
-        Members: *const &RustArchiveMember<'_>,
-        WriteSymbtab: bool,
-        Kind: ArchiveKind,
-        isEC: bool,
-    ) -> LLVMRustResult;
-    pub(crate) fn LLVMRustArchiveMemberNew<'a>(
-        Filename: *const c_char,
-        Name: *const c_char,
-        Child: Option<&ArchiveChild<'a>>,
-    ) -> &'a mut RustArchiveMember<'a>;
-    pub(crate) fn LLVMRustArchiveMemberFree<'a>(Member: &'a mut RustArchiveMember<'a>);
-
     pub(crate) fn LLVMRustSetDataLayoutFromTargetMachine<'a>(M: &'a Module, TM: &'a TargetMachine);
 
     pub(crate) fn LLVMRustPositionBuilderPastAllocas<'a>(B: &Builder<'a>, Fn: &'a Value);

compiler/rustc_codegen_llvm/src/llvm/mod.rs

@@ -3,7 +3,6 @@
 use std::ffi::{CStr, CString};
 use std::num::NonZero;
 use std::ptr;
-use std::str::FromStr;
 use std::string::FromUtf8Error;
 
 use libc::c_uint;
@@ -16,7 +15,6 @@ pub(crate) use self::MetadataType::*;
 pub(crate) use self::ffi::*;
 use crate::common::AsCCharPtr;
 
-pub(crate) mod archive_ro;
 pub(crate) mod diagnostic;
 pub(crate) mod enzyme_ffi;
 mod ffi;
@@ -152,21 +150,6 @@ pub(crate) enum CodeGenOptSize {
     CodeGenOptSizeAggressive = 2,
 }
 
-impl FromStr for ArchiveKind {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "gnu" => Ok(ArchiveKind::K_GNU),
-            "bsd" => Ok(ArchiveKind::K_BSD),
-            "darwin" => Ok(ArchiveKind::K_DARWIN),
-            "coff" => Ok(ArchiveKind::K_COFF),
-            "aix_big" => Ok(ArchiveKind::K_AIXBIG),
-            _ => Err(()),
-        }
-    }
-}
-
 pub(crate) fn SetInstructionCallConv(instr: &Value, cc: CallConv) {
     unsafe {
         LLVMSetInstructionCallConv(instr, cc as c_uint);

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -277,6 +277,7 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         {
             None
         }
+        ("loongarch32" | "loongarch64", "32s") if get_version().0 < 21 => None,
         // Filter out features that are not supported by the current LLVM version
         ("riscv32" | "riscv64", "zacas") if get_version().0 < 20 => None,
         (

compiler/rustc_codegen_llvm/src/type_.rs

@@ -204,7 +204,7 @@ impl<'ll, CX: Borrow<SCx<'ll>>> BaseTypeCodegenMethods for GenericCx<'ll, CX> {
     }
 
     fn type_kind(&self, ty: &'ll Type) -> TypeKind {
-        unsafe { llvm::LLVMRustGetTypeKind(ty).to_generic() }
+        llvm::LLVMGetTypeKind(ty).to_rust().to_generic()
     }
 
     fn type_ptr(&self) -> &'ll Type {

compiler/rustc_codegen_ssa/messages.ftl

@@ -171,8 +171,8 @@ codegen_ssa_invalid_monomorphization_unsupported_symbol = invalid monomorphizati
 
 codegen_ssa_invalid_monomorphization_unsupported_symbol_of_size = invalid monomorphization of `{$name}` intrinsic: unsupported {$symbol} from `{$in_ty}` with element `{$in_elem}` of size `{$size}` to `{$ret_ty}`
 
-codegen_ssa_invalid_no_sanitize = invalid argument for `no_sanitize`
-    .note = expected one of: `address`, `cfi`, `hwaddress`, `kcfi`, `memory`, `memtag`, `shadow-call-stack`, or `thread`
+codegen_ssa_invalid_sanitize = invalid argument for `sanitize`
+    .note = expected one of: `address`, `kernel_address`, `cfi`, `hwaddress`, `kcfi`, `memory`, `memtag`, `shadow_call_stack`, or `thread`
 
 codegen_ssa_invalid_windows_subsystem = invalid windows subsystem `{$subsystem}`, only `windows` and `console` are allowed
 

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2435,6 +2435,13 @@ fn linker_with_args(
     // Passed after compiler-generated options to support manual overriding when necessary.
     add_user_defined_link_args(cmd, sess);
 
+    // ------------ Builtin configurable linker scripts ------------
+    // The user's link args should be able to overwrite symbols in the compiler's
+    // linker script that were weakly defined (i.e. defined with `PROVIDE()`). For this
+    // to work correctly, the user needs to be able to specify linker arguments like
+    // `--defsym` and `--script` *before* any builtin linker scripts are evaluated.
+    add_link_script(cmd, sess, tmpdir, crate_type);
+
     // ------------ Object code and libraries, order-dependent ------------
 
     // Post-link CRT objects.
@@ -2469,8 +2476,6 @@ fn add_order_independent_options(
 
     let apple_sdk_root = add_apple_sdk(cmd, sess, flavor);
 
-    add_link_script(cmd, sess, tmpdir, crate_type);
-
     if sess.target.os == "fuchsia"
         && crate_type == CrateType::Executable
         && !matches!(flavor, LinkerFlavor::Gnu(Cc::Yes, _))

compiler/rustc_codegen_ssa/src/base.rs

@@ -858,7 +858,7 @@ pub fn is_call_from_compiler_builtins_to_upstream_monomorphization<'tcx>(
     instance: Instance<'tcx>,
 ) -> bool {
     fn is_llvm_intrinsic(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
-        if let Some(name) = tcx.codegen_fn_attrs(def_id).link_name {
+        if let Some(name) = tcx.codegen_fn_attrs(def_id).symbol_name {
             name.as_str().starts_with("llvm.")
         } else {
             false

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -76,32 +76,6 @@ fn parse_instruction_set_attr(tcx: TyCtxt<'_>, attr: &Attribute) -> Option<Instr
     }
 }
 
-// FIXME(jdonszelmann): remove when no_sanitize becomes a parsed attr
-fn parse_no_sanitize_attr(tcx: TyCtxt<'_>, attr: &Attribute) -> Option<SanitizerSet> {
-    let list = attr.meta_item_list()?;
-    let mut sanitizer_set = SanitizerSet::empty();
-
-    for item in list.iter() {
-        match item.name() {
-            Some(sym::address) => {
-                sanitizer_set |= SanitizerSet::ADDRESS | SanitizerSet::KERNELADDRESS
-            }
-            Some(sym::cfi) => sanitizer_set |= SanitizerSet::CFI,
-            Some(sym::kcfi) => sanitizer_set |= SanitizerSet::KCFI,
-            Some(sym::memory) => sanitizer_set |= SanitizerSet::MEMORY,
-            Some(sym::memtag) => sanitizer_set |= SanitizerSet::MEMTAG,
-            Some(sym::shadow_call_stack) => sanitizer_set |= SanitizerSet::SHADOWCALLSTACK,
-            Some(sym::thread) => sanitizer_set |= SanitizerSet::THREAD,
-            Some(sym::hwaddress) => sanitizer_set |= SanitizerSet::HWADDRESS,
-            _ => {
-                tcx.dcx().emit_err(errors::InvalidNoSanitize { span: item.span() });
-            }
-        }
-    }
-
-    Some(sanitizer_set)
-}
-
 // FIXME(jdonszelmann): remove when patchable_function_entry becomes a parsed attr
 fn parse_patchable_function_entry(
     tcx: TyCtxt<'_>,
@@ -160,7 +134,7 @@ fn parse_patchable_function_entry(
 #[derive(Default)]
 struct InterestingAttributeDiagnosticSpans {
     link_ordinal: Option<Span>,
-    no_sanitize: Option<Span>,
+    sanitize: Option<Span>,
     inline: Option<Span>,
     no_mangle: Option<Span>,
 }
@@ -181,7 +155,7 @@ fn process_builtin_attrs(
             match p {
                 AttributeKind::Cold(_) => codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD,
                 AttributeKind::ExportName { name, .. } => {
-                    codegen_fn_attrs.export_name = Some(*name)
+                    codegen_fn_attrs.symbol_name = Some(*name)
                 }
                 AttributeKind::Inline(inline, span) => {
                     codegen_fn_attrs.inline = *inline;
@@ -189,7 +163,13 @@ fn process_builtin_attrs(
                 }
                 AttributeKind::Naked(_) => codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED,
                 AttributeKind::Align { align, .. } => codegen_fn_attrs.alignment = Some(*align),
-                AttributeKind::LinkName { name, .. } => codegen_fn_attrs.link_name = Some(*name),
+                AttributeKind::LinkName { name, .. } => {
+                    // FIXME Remove check for foreign functions once #[link_name] on non-foreign
+                    // functions is a hard error
+                    if tcx.is_foreign_item(did) {
+                        codegen_fn_attrs.symbol_name = Some(*name);
+                    }
+                }
                 AttributeKind::LinkOrdinal { ordinal, span } => {
                     codegen_fn_attrs.link_ordinal = Some(*ordinal);
                     interesting_spans.link_ordinal = Some(*span);
@@ -329,11 +309,7 @@ fn process_builtin_attrs(
                 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR_ZEROED
             }
             sym::thread_local => codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL,
-            sym::no_sanitize => {
-                interesting_spans.no_sanitize = Some(attr.span());
-                codegen_fn_attrs.no_sanitize |=
-                    parse_no_sanitize_attr(tcx, attr).unwrap_or_default();
-            }
+            sym::sanitize => interesting_spans.sanitize = Some(attr.span()),
             sym::instruction_set => {
                 codegen_fn_attrs.instruction_set = parse_instruction_set_attr(tcx, attr)
             }
@@ -357,6 +333,8 @@ fn apply_overrides(tcx: TyCtxt<'_>, did: LocalDefId, codegen_fn_attrs: &mut Code
     codegen_fn_attrs.alignment =
         Ord::max(codegen_fn_attrs.alignment, tcx.sess.opts.unstable_opts.min_function_alignment);
 
+    // Compute the disabled sanitizers.
+    codegen_fn_attrs.no_sanitize |= tcx.disabled_sanitizers_for(did);
     // On trait methods, inherit the `#[align]` of the trait's method prototype.
     codegen_fn_attrs.alignment = Ord::max(codegen_fn_attrs.alignment, tcx.inherited_align(did));
 
@@ -409,7 +387,7 @@ fn apply_overrides(tcx: TyCtxt<'_>, did: LocalDefId, codegen_fn_attrs: &mut Code
             // * `#[rustc_std_internal_symbol]` mangles the symbol name in a special way
             //   both for exports and imports through foreign items. This is handled further,
             //   during symbol mangling logic.
-        } else if codegen_fn_attrs.link_name.is_some() {
+        } else if codegen_fn_attrs.symbol_name.is_some() {
             // * This can be overridden with the `#[link_name]` attribute
         } else {
             // NOTE: there's one more exception that we cannot apply here. On wasm,
@@ -454,17 +432,17 @@ fn check_result(
     if !codegen_fn_attrs.no_sanitize.is_empty()
         && codegen_fn_attrs.inline.always()
         && let (Some(no_sanitize_span), Some(inline_span)) =
-            (interesting_spans.no_sanitize, interesting_spans.inline)
+            (interesting_spans.sanitize, interesting_spans.inline)
     {
         let hir_id = tcx.local_def_id_to_hir_id(did);
         tcx.node_span_lint(lint::builtin::INLINE_NO_SANITIZE, hir_id, no_sanitize_span, |lint| {
-            lint.primary_message("`no_sanitize` will have no effect after inlining");
+            lint.primary_message("setting `sanitize` off will have no effect after inlining");
             lint.span_note(inline_span, "inlining requested here");
         })
     }
 
     // error when specifying link_name together with link_ordinal
-    if let Some(_) = codegen_fn_attrs.link_name
+    if let Some(_) = codegen_fn_attrs.symbol_name
         && let Some(_) = codegen_fn_attrs.link_ordinal
     {
         let msg = "cannot use `#[link_name]` with `#[link_ordinal]`";
@@ -515,8 +493,7 @@ fn handle_lang_items(
         && let Some(link_name) = lang_item.link_name()
     {
         codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
-        codegen_fn_attrs.export_name = Some(link_name);
-        codegen_fn_attrs.link_name = Some(link_name);
+        codegen_fn_attrs.symbol_name = Some(link_name);
     }
 
     // error when using no_mangle on a lang item item
@@ -582,6 +559,93 @@ fn opt_trait_item(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
     }
 }
 
+/// For an attr that has the `sanitize` attribute, read the list of
+/// disabled sanitizers. `current_attr` holds the information about
+/// previously parsed attributes.
+fn parse_sanitize_attr(
+    tcx: TyCtxt<'_>,
+    attr: &Attribute,
+    current_attr: SanitizerSet,
+) -> SanitizerSet {
+    let mut result = current_attr;
+    if let Some(list) = attr.meta_item_list() {
+        for item in list.iter() {
+            let MetaItemInner::MetaItem(set) = item else {
+                tcx.dcx().emit_err(errors::InvalidSanitize { span: attr.span() });
+                break;
+            };
+            let segments = set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
+            match segments.as_slice() {
+                // Similar to clang, sanitize(address = ..) and
+                // sanitize(kernel_address = ..) control both ASan and KASan
+                // Source: https://reviews.llvm.org/D44981.
+                [sym::address] | [sym::kernel_address] if set.value_str() == Some(sym::off) => {
+                    result |= SanitizerSet::ADDRESS | SanitizerSet::KERNELADDRESS
+                }
+                [sym::address] | [sym::kernel_address] if set.value_str() == Some(sym::on) => {
+                    result &= !SanitizerSet::ADDRESS;
+                    result &= !SanitizerSet::KERNELADDRESS;
+                }
+                [sym::cfi] if set.value_str() == Some(sym::off) => result |= SanitizerSet::CFI,
+                [sym::cfi] if set.value_str() == Some(sym::on) => result &= !SanitizerSet::CFI,
+                [sym::kcfi] if set.value_str() == Some(sym::off) => result |= SanitizerSet::KCFI,
+                [sym::kcfi] if set.value_str() == Some(sym::on) => result &= !SanitizerSet::KCFI,
+                [sym::memory] if set.value_str() == Some(sym::off) => {
+                    result |= SanitizerSet::MEMORY
+                }
+                [sym::memory] if set.value_str() == Some(sym::on) => {
+                    result &= !SanitizerSet::MEMORY
+                }
+                [sym::memtag] if set.value_str() == Some(sym::off) => {
+                    result |= SanitizerSet::MEMTAG
+                }
+                [sym::memtag] if set.value_str() == Some(sym::on) => {
+                    result &= !SanitizerSet::MEMTAG
+                }
+                [sym::shadow_call_stack] if set.value_str() == Some(sym::off) => {
+                    result |= SanitizerSet::SHADOWCALLSTACK
+                }
+                [sym::shadow_call_stack] if set.value_str() == Some(sym::on) => {
+                    result &= !SanitizerSet::SHADOWCALLSTACK
+                }
+                [sym::thread] if set.value_str() == Some(sym::off) => {
+                    result |= SanitizerSet::THREAD
+                }
+                [sym::thread] if set.value_str() == Some(sym::on) => {
+                    result &= !SanitizerSet::THREAD
+                }
+                [sym::hwaddress] if set.value_str() == Some(sym::off) => {
+                    result |= SanitizerSet::HWADDRESS
+                }
+                [sym::hwaddress] if set.value_str() == Some(sym::on) => {
+                    result &= !SanitizerSet::HWADDRESS
+                }
+                _ => {
+                    tcx.dcx().emit_err(errors::InvalidSanitize { span: attr.span() });
+                }
+            }
+        }
+    }
+    result
+}
+
+fn disabled_sanitizers_for(tcx: TyCtxt<'_>, did: LocalDefId) -> SanitizerSet {
+    // Backtrack to the crate root.
+    let disabled = match tcx.opt_local_parent(did) {
+        // Check the parent (recursively).
+        Some(parent) => tcx.disabled_sanitizers_for(parent),
+        // We reached the crate root without seeing an attribute, so
+        // there is no sanitizers to exclude.
+        None => SanitizerSet::empty(),
+    };
+
+    // Check for a sanitize annotation directly on this def.
+    if let Some(attr) = tcx.get_attr(did, sym::sanitize) {
+        return parse_sanitize_attr(tcx, attr, disabled);
+    }
+    disabled
+}
+
 /// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller
 /// applied to the method prototype.
 fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
@@ -706,6 +770,11 @@ pub fn autodiff_attrs(tcx: TyCtxt<'_>, id: DefId) -> Option<AutoDiffAttrs> {
 }
 
 pub(crate) fn provide(providers: &mut Providers) {
-    *providers =
-        Providers { codegen_fn_attrs, should_inherit_track_caller, inherited_align, ..*providers };
+    *providers = Providers {
+        codegen_fn_attrs,
+        should_inherit_track_caller,
+        inherited_align,
+        disabled_sanitizers_for,
+        ..*providers
+    };
 }

compiler/rustc_codegen_ssa/src/errors.rs

@@ -1121,9 +1121,9 @@ impl IntoDiagArg for ExpectedPointerMutability {
 }
 
 #[derive(Diagnostic)]
-#[diag(codegen_ssa_invalid_no_sanitize)]
+#[diag(codegen_ssa_invalid_sanitize)]
 #[note]
-pub(crate) struct InvalidNoSanitize {
+pub(crate) struct InvalidSanitize {
     #[primary_span]
     pub span: Span,
 }

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -180,6 +180,7 @@ fn parse_rust_feature_flag<'a>(
             while let Some(new_feature) = new_features.pop() {
                 if features.insert(new_feature) {
                     if let Some(implied_features) = inverse_implied_features.get(&new_feature) {
+                        #[allow(rustc::potential_query_instability)]
                         new_features.extend(implied_features)
                     }
                 }

compiler/rustc_const_eval/src/interpret/call.rs

@@ -27,8 +27,9 @@ use crate::{enter_trace_span, fluent_generated as fluent};
 pub enum FnArg<'tcx, Prov: Provenance = CtfeProvenance> {
     /// Pass a copy of the given operand.
     Copy(OpTy<'tcx, Prov>),
-    /// Allow for the argument to be passed in-place: destroy the value originally stored at that place and
-    /// make the place inaccessible for the duration of the function call.
+    /// Allow for the argument to be passed in-place: destroy the value originally stored at that
+    /// place and make the place inaccessible for the duration of the function call. This *must* be
+    /// an in-memory place so that we can do the proper alias checks.
     InPlace(MPlaceTy<'tcx, Prov>),
 }
 
@@ -379,6 +380,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             }
         }
 
+        // *Before* pushing the new frame, determine whether the return destination is in memory.
+        // Need to use `place_to_op` to be *sure* we get the mplace if there is one.
+        let destination_mplace = self.place_to_op(destination)?.as_mplace_or_imm().left();
+
+        // Push the "raw" frame -- this leaves locals uninitialized.
         self.push_stack_frame_raw(instance, body, destination, cont)?;
 
         // If an error is raised here, pop the frame again to get an accurate backtrace.
@@ -496,7 +502,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
             // Protect return place for in-place return value passing.
             // We only need to protect anything if this is actually an in-memory place.
-            if let Left(mplace) = destination.as_mplace_or_local() {
+            if let Some(mplace) = destination_mplace {
                 M::protect_in_place_function_argument(self, &mplace)?;
             }
 

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -325,8 +325,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         let _trace = enter_trace_span!(
             M,
             "instantiate_from_frame_and_normalize_erasing_regions",
-            "{}",
-            frame.instance
+            %frame.instance
         );
         frame
             .instance
@@ -583,6 +582,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         span: Span,
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
+        let _trace = enter_trace_span!(M, const_eval::eval_mir_constant, ?val);
         let const_val = val.eval(*self.tcx, self.typing_env, span).map_err(|err| {
                 if M::ALL_CONSTS_ARE_PRECHECKED {
                     match err {

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -175,6 +175,16 @@ impl<Prov: Provenance> Immediate<Prov> {
         }
         interp_ok(())
     }
+
+    pub fn has_provenance(&self) -> bool {
+        match self {
+            Immediate::Scalar(scalar) => matches!(scalar, Scalar::Ptr { .. }),
+            Immediate::ScalarPair(s1, s2) => {
+                matches!(s1, Scalar::Ptr { .. }) || matches!(s2, Scalar::Ptr { .. })
+            }
+            Immediate::Uninit => false,
+        }
+    }
 }
 
 // ScalarPair needs a type to interpret, so we often have an immediate and a type together

compiler/rustc_const_eval/src/interpret/place.rs

@@ -234,6 +234,12 @@ impl<'tcx, Prov: Provenance> PlaceTy<'tcx, Prov> {
     }
 
     /// A place is either an mplace or some local.
+    ///
+    /// Note that the return value can be different even for logically identical places!
+    /// Specifically, if a local is stored in-memory, this may return `Local` or `MPlaceTy`
+    /// depending on how the place was constructed. In other words, seeing `Local` here does *not*
+    /// imply that this place does not point to memory. Every caller must therefore always handle
+    /// both cases.
     #[inline(always)]
     pub fn as_mplace_or_local(
         &self,
@@ -759,6 +765,13 @@ where
         &mut self,
         dest: &impl Writeable<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx> {
+        // If this is an efficiently represented local variable without provenance, skip the
+        // `as_mplace_or_mutable_local` that would otherwise force this local into memory.
+        if let Right(imm) = dest.to_op(self)?.as_mplace_or_imm() {
+            if !imm.has_provenance() {
+                return interp_ok(());
+            }
+        }
         match self.as_mplace_or_mutable_local(&dest.to_place())? {
             Right((local_val, _local_layout, local)) => {
                 local_val.clear_provenance()?;

compiler/rustc_const_eval/src/interpret/stack.rs

@@ -20,7 +20,7 @@ use super::{
     MemoryKind, Operand, PlaceTy, Pointer, Provenance, ReturnAction, Scalar, from_known_layout,
     interp_ok, throw_ub, throw_unsup,
 };
-use crate::errors;
+use crate::{enter_trace_span, errors};
 
 // The Phantomdata exists to prevent this type from being `Send`. If it were sent across a thread
 // boundary and dropped in the other thread, it would exit the span in the other thread.
@@ -386,6 +386,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
         // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check).
         for &const_ in body.required_consts() {
+            // We can't use `eval_mir_constant` here as that assumes that all required consts have
+            // already been checked, so we need a separate tracing call.
+            let _trace = enter_trace_span!(M, const_eval::required_consts, ?const_.const_);
             let c =
                 self.instantiate_from_current_frame_and_normalize_erasing_regions(const_.const_)?;
             c.eval(*self.tcx, self.typing_env, const_.span).map_err(|err| {

compiler/rustc_const_eval/src/interpret/step.rs

@@ -4,6 +4,7 @@
 
 use either::Either;
 use rustc_abi::{FIRST_VARIANT, FieldIdx};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_index::IndexSlice;
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_middle::{bug, mir, span_bug};
@@ -389,8 +390,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
 
     /// Evaluate the arguments of a function call
     fn eval_fn_call_argument(
-        &self,
+        &mut self,
         op: &mir::Operand<'tcx>,
+        move_definitely_disjoint: bool,
     ) -> InterpResult<'tcx, FnArg<'tcx, M::Provenance>> {
         interp_ok(match op {
             mir::Operand::Copy(_) | mir::Operand::Constant(_) => {
@@ -399,24 +401,19 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 FnArg::Copy(op)
             }
             mir::Operand::Move(place) => {
-                // If this place lives in memory, preserve its location.
-                // We call `place_to_op` which will be an `MPlaceTy` whenever there exists
-                // an mplace for this place. (This is in contrast to `PlaceTy::as_mplace_or_local`
-                // which can return a local even if that has an mplace.)
                 let place = self.eval_place(*place)?;
-                let op = self.place_to_op(&place)?;
-
-                match op.as_mplace_or_imm() {
-                    Either::Left(mplace) => FnArg::InPlace(mplace),
-                    Either::Right(_imm) => {
-                        // This argument doesn't live in memory, so there's no place
-                        // to make inaccessible during the call.
-                        // We rely on there not being any stray `PlaceTy` that would let the
-                        // caller directly access this local!
-                        // This is also crucial for tail calls, where we want the `FnArg` to
-                        // stay valid when the old stack frame gets popped.
-                        FnArg::Copy(op)
+                if move_definitely_disjoint {
+                    // We still have to ensure that no *other* pointers are used to access this place,
+                    // so *if* it is in memory then we have to treat it as `InPlace`.
+                    // Use `place_to_op` to guarantee that we notice it being in memory.
+                    let op = self.place_to_op(&place)?;
+                    match op.as_mplace_or_imm() {
+                        Either::Left(mplace) => FnArg::InPlace(mplace),
+                        Either::Right(_imm) => FnArg::Copy(op),
                     }
+                } else {
+                    // We have to force this into memory to detect aliasing among `Move` arguments.
+                    FnArg::InPlace(self.force_allocation(&place)?)
                 }
             }
         })
@@ -425,18 +422,46 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     /// Shared part of `Call` and `TailCall` implementation — finding and evaluating all the
     /// necessary information about callee and arguments to make a call.
     fn eval_callee_and_args(
-        &self,
+        &mut self,
         terminator: &mir::Terminator<'tcx>,
         func: &mir::Operand<'tcx>,
         args: &[Spanned<mir::Operand<'tcx>>],
     ) -> InterpResult<'tcx, EvaluatedCalleeAndArgs<'tcx, M>> {
         let func = self.eval_operand(func, None)?;
+
+        // Evaluating function call arguments. The tricky part here is dealing with `Move`
+        // arguments: we have to ensure no two such arguments alias. This would be most easily done
+        // by just forcing them all into memory and then doing the usual in-place argument
+        // protection, but then we'd force *a lot* of arguments into memory. So we do some syntactic
+        // pre-processing here where if all `move` arguments are syntactically distinct local
+        // variables (and none is indirect), we can skip the in-memory forcing.
+        let move_definitely_disjoint = 'move_definitely_disjoint: {
+            let mut previous_locals = FxHashSet::<mir::Local>::default();
+            for arg in args {
+                let mir::Operand::Move(place) = arg.node else {
+                    continue; // we can skip non-`Move` arguments.
+                };
+                if place.is_indirect_first_projection() {
+                    // An indirect `Move` argument could alias with anything else...
+                    break 'move_definitely_disjoint false;
+                }
+                if !previous_locals.insert(place.local) {
+                    // This local is the base for two arguments! They might overlap.
+                    break 'move_definitely_disjoint false;
+                }
+            }
+            // We found no violation so they are all definitely disjoint.
+            true
+        };
         let args = args
             .iter()
-            .map(|arg| self.eval_fn_call_argument(&arg.node))
+            .map(|arg| self.eval_fn_call_argument(&arg.node, move_definitely_disjoint))
             .collect::<InterpResult<'tcx, Vec<_>>>()?;
 
-        let fn_sig_binder = func.layout.ty.fn_sig(*self.tcx);
+        let fn_sig_binder = {
+            let _trace = enter_trace_span!(M, "fn_sig", ty = ?func.layout.ty.kind());
+            func.layout.ty.fn_sig(*self.tcx)
+        };
         let fn_sig = self.tcx.normalize_erasing_late_bound_regions(self.typing_env, fn_sig_binder);
         let extra_args = &args[fn_sig.inputs().len()..];
         let extra_args =

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -1418,7 +1418,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         let _trace = enter_trace_span!(
             M,
             "validate_operand",
-            "recursive={recursive}, reset_provenance_and_padding={reset_provenance_and_padding}, val={val:?}"
+            recursive,
+            reset_provenance_and_padding,
+            ?val,
         );
 
         // Note that we *could* actually be in CTFE here with `-Zextra-const-ub-checks`, but it's

compiler/rustc_errors/src/diagnostic_impls.rs

@@ -9,6 +9,7 @@ use rustc_abi::TargetDataLayoutErrors;
 use rustc_ast::util::parser::ExprPrecedence;
 use rustc_ast_pretty::pprust;
 use rustc_hir::RustcVersion;
+use rustc_hir::attrs::{MirDialect, MirPhase};
 use rustc_macros::Subdiagnostic;
 use rustc_span::edition::Edition;
 use rustc_span::{Ident, MacroRulesNormalizedIdent, Span, Symbol};
@@ -312,6 +313,28 @@ impl IntoDiagArg for ExprPrecedence {
     }
 }
 
+impl IntoDiagArg for MirDialect {
+    fn into_diag_arg(self, _path: &mut Option<PathBuf>) -> DiagArgValue {
+        let arg = match self {
+            MirDialect::Analysis => "analysis",
+            MirDialect::Built => "built",
+            MirDialect::Runtime => "runtime",
+        };
+        DiagArgValue::Str(Cow::Borrowed(arg))
+    }
+}
+
+impl IntoDiagArg for MirPhase {
+    fn into_diag_arg(self, _path: &mut Option<PathBuf>) -> DiagArgValue {
+        let arg = match self {
+            MirPhase::Initial => "initial",
+            MirPhase::PostCleanup => "post-cleanup",
+            MirPhase::Optimized => "optimized",
+        };
+        DiagArgValue::Str(Cow::Borrowed(arg))
+    }
+}
+
 #[derive(Clone)]
 pub struct DiagSymbolList<S = Symbol>(Vec<S>);
 

compiler/rustc_errors/src/emitter.rs

@@ -17,7 +17,7 @@ use std::path::Path;
 use std::sync::Arc;
 
 use derive_setters::Setters;
-use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
+use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::sync::{DynSend, IntoDynSyncSend};
 use rustc_error_messages::{FluentArgs, SpanLabel};
 use rustc_lexer;
@@ -1853,7 +1853,7 @@ impl HumanEmitter {
                             && line_idx + 1 == annotated_file.lines.len(),
                     );
 
-                    let mut to_add = FxHashMap::default();
+                    let mut to_add = FxIndexMap::default();
 
                     for (depth, style) in depths {
                         // FIXME(#120456) - is `swap_remove` correct?

compiler/rustc_expand/messages.ftl

@@ -70,7 +70,7 @@ expand_invalid_fragment_specifier =
     invalid fragment specifier `{$fragment}`
     .help = {$help}
 
-expand_macro_args_bad_delim = macro attribute argument matchers require parentheses
+expand_macro_args_bad_delim = `{$rule_kw}` rule argument matchers require parentheses
 expand_macro_args_bad_delim_sugg = the delimiters should be `(` and `)`
 
 expand_macro_body_stability =

compiler/rustc_expand/src/errors.rs

@@ -490,6 +490,7 @@ pub(crate) struct MacroArgsBadDelim {
     pub span: Span,
     #[subdiagnostic]
     pub sugg: MacroArgsBadDelimSugg,
+    pub rule_kw: Symbol,
 }
 
 #[derive(Subdiagnostic)]

compiler/rustc_expand/src/expand.rs

@@ -16,6 +16,7 @@ use rustc_attr_parsing::{EvalConfigResult, ShouldEmit};
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
 use rustc_errors::PResult;
 use rustc_feature::Features;
+use rustc_hir::def::MacroKinds;
 use rustc_parse::parser::{
     AttemptLocalParseRecovery, CommaRecoveryMode, ForceCollect, Parser, RecoverColon, RecoverComma,
     token_descr,
@@ -565,6 +566,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                 .map(|DeriveResolution { path, item, exts: _, is_const }| {
                                     // FIXME: Consider using the derive resolutions (`_exts`)
                                     // instead of enqueuing the derives to be resolved again later.
+                                    // Note that this can result in duplicate diagnostics.
                                     let expn_id = LocalExpnId::fresh_empty();
                                     derive_invocations.push((
                                         Invocation {
@@ -922,6 +924,35 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                     }
                     fragment
                 }
+                SyntaxExtensionKind::MacroRules(expander)
+                    if expander.kinds().contains(MacroKinds::DERIVE) =>
+                {
+                    if is_const {
+                        let guar = self
+                            .cx
+                            .dcx()
+                            .span_err(span, "macro `derive` does not support const derives");
+                        return ExpandResult::Ready(fragment_kind.dummy(span, guar));
+                    }
+                    let body = item.to_tokens();
+                    match expander.expand_derive(self.cx, span, &body) {
+                        Ok(tok_result) => {
+                            let fragment =
+                                self.parse_ast_fragment(tok_result, fragment_kind, &path, span);
+                            if macro_stats {
+                                update_derive_macro_stats(
+                                    self.cx,
+                                    fragment_kind,
+                                    span,
+                                    &path,
+                                    &fragment,
+                                );
+                            }
+                            fragment
+                        }
+                        Err(guar) => return ExpandResult::Ready(fragment_kind.dummy(span, guar)),
+                    }
+                }
                 _ => unreachable!(),
             },
             InvocationKind::GlobDelegation { item, of_trait } => {

compiler/rustc_expand/src/mbe/diagnostics.rs

@@ -14,14 +14,22 @@ use super::macro_rules::{MacroRule, NoopTracker, parser_from_cx};
 use crate::expand::{AstFragmentKind, parse_ast_fragment};
 use crate::mbe::macro_parser::ParseResult::*;
 use crate::mbe::macro_parser::{MatcherLoc, NamedParseResult, TtParser};
-use crate::mbe::macro_rules::{Tracker, try_match_macro, try_match_macro_attr};
+use crate::mbe::macro_rules::{
+    Tracker, try_match_macro, try_match_macro_attr, try_match_macro_derive,
+};
+
+pub(super) enum FailedMacro<'a> {
+    Func,
+    Attr(&'a TokenStream),
+    Derive,
+}
 
 pub(super) fn failed_to_match_macro(
     psess: &ParseSess,
     sp: Span,
     def_span: Span,
     name: Ident,
-    attr_args: Option<&TokenStream>,
+    args: FailedMacro<'_>,
     body: &TokenStream,
     rules: &[MacroRule],
 ) -> (Span, ErrorGuaranteed) {
@@ -36,10 +44,12 @@ pub(super) fn failed_to_match_macro(
     // diagnostics.
     let mut tracker = CollectTrackerAndEmitter::new(psess.dcx(), sp);
 
-    let try_success_result = if let Some(attr_args) = attr_args {
-        try_match_macro_attr(psess, name, attr_args, body, rules, &mut tracker)
-    } else {
-        try_match_macro(psess, name, body, rules, &mut tracker)
+    let try_success_result = match args {
+        FailedMacro::Func => try_match_macro(psess, name, body, rules, &mut tracker),
+        FailedMacro::Attr(attr_args) => {
+            try_match_macro_attr(psess, name, attr_args, body, rules, &mut tracker)
+        }
+        FailedMacro::Derive => try_match_macro_derive(psess, name, body, rules, &mut tracker),
     };
 
     if try_success_result.is_ok() {
@@ -90,7 +100,7 @@ pub(super) fn failed_to_match_macro(
     }
 
     // Check whether there's a missing comma in this macro call, like `println!("{}" a);`
-    if attr_args.is_none()
+    if let FailedMacro::Func = args
         && let Some((body, comma_span)) = body.add_comma()
     {
         for rule in rules {

compiler/rustc_expand/src/mbe/macro_rules.rs

@@ -27,10 +27,10 @@ use rustc_session::Session;
 use rustc_session::parse::{ParseSess, feature_err};
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::Transparency;
-use rustc_span::{Ident, Span, kw, sym};
+use rustc_span::{Ident, Span, Symbol, kw, sym};
 use tracing::{debug, instrument, trace, trace_span};
 
-use super::diagnostics::failed_to_match_macro;
+use super::diagnostics::{FailedMacro, failed_to_match_macro};
 use super::macro_parser::{NamedMatches, NamedParseResult};
 use super::{SequenceRepetition, diagnostics};
 use crate::base::{
@@ -138,6 +138,8 @@ pub(super) enum MacroRule {
         body_span: Span,
         rhs: mbe::TokenTree,
     },
+    /// A derive rule, for use with `#[m]`
+    Derive { body: Vec<MatcherLoc>, body_span: Span, rhs: mbe::TokenTree },
 }
 
 pub struct MacroRulesMacroExpander {
@@ -157,6 +159,7 @@ impl MacroRulesMacroExpander {
             MacroRule::Attr { args_span, body_span, ref rhs, .. } => {
                 (MultiSpan::from_spans(vec![args_span, body_span]), rhs)
             }
+            MacroRule::Derive { body_span, ref rhs, .. } => (MultiSpan::from_span(body_span), rhs),
         };
         if has_compile_error_macro(rhs) { None } else { Some((&self.name, span)) }
     }
@@ -164,6 +167,63 @@ impl MacroRulesMacroExpander {
     pub fn kinds(&self) -> MacroKinds {
         self.kinds
     }
+
+    pub fn expand_derive(
+        &self,
+        cx: &mut ExtCtxt<'_>,
+        sp: Span,
+        body: &TokenStream,
+    ) -> Result<TokenStream, ErrorGuaranteed> {
+        // This is similar to `expand_macro`, but they have very different signatures, and will
+        // diverge further once derives support arguments.
+        let Self { name, ref rules, node_id, .. } = *self;
+        let psess = &cx.sess.psess;
+
+        if cx.trace_macros() {
+            let msg = format!("expanding `#[derive({name})] {}`", pprust::tts_to_string(body));
+            trace_macros_note(&mut cx.expansions, sp, msg);
+        }
+
+        match try_match_macro_derive(psess, name, body, rules, &mut NoopTracker) {
+            Ok((rule_index, rule, named_matches)) => {
+                let MacroRule::Derive { rhs, .. } = rule else {
+                    panic!("try_match_macro_derive returned non-derive rule");
+                };
+                let mbe::TokenTree::Delimited(rhs_span, _, rhs) = rhs else {
+                    cx.dcx().span_bug(sp, "malformed macro derive rhs");
+                };
+
+                let id = cx.current_expansion.id;
+                let tts = transcribe(psess, &named_matches, rhs, *rhs_span, self.transparency, id)
+                    .map_err(|e| e.emit())?;
+
+                if cx.trace_macros() {
+                    let msg = format!("to `{}`", pprust::tts_to_string(&tts));
+                    trace_macros_note(&mut cx.expansions, sp, msg);
+                }
+
+                if is_defined_in_current_crate(node_id) {
+                    cx.resolver.record_macro_rule_usage(node_id, rule_index);
+                }
+
+                Ok(tts)
+            }
+            Err(CanRetry::No(guar)) => Err(guar),
+            Err(CanRetry::Yes) => {
+                let (_, guar) = failed_to_match_macro(
+                    cx.psess(),
+                    sp,
+                    self.span,
+                    name,
+                    FailedMacro::Derive,
+                    body,
+                    rules,
+                );
+                cx.macro_error_and_trace_macros_diag();
+                Err(guar)
+            }
+        }
+    }
 }
 
 impl TTMacroExpander for MacroRulesMacroExpander {
@@ -325,8 +385,15 @@ fn expand_macro<'cx>(
         }
         Err(CanRetry::Yes) => {
             // Retry and emit a better error.
-            let (span, guar) =
-                failed_to_match_macro(cx.psess(), sp, def_span, name, None, &arg, rules);
+            let (span, guar) = failed_to_match_macro(
+                cx.psess(),
+                sp,
+                def_span,
+                name,
+                FailedMacro::Func,
+                &arg,
+                rules,
+            );
             cx.macro_error_and_trace_macros_diag();
             DummyResult::any(span, guar)
         }
@@ -388,8 +455,15 @@ fn expand_macro_attr(
         Err(CanRetry::No(guar)) => Err(guar),
         Err(CanRetry::Yes) => {
             // Retry and emit a better error.
-            let (_, guar) =
-                failed_to_match_macro(cx.psess(), sp, def_span, name, Some(&args), &body, rules);
+            let (_, guar) = failed_to_match_macro(
+                cx.psess(),
+                sp,
+                def_span,
+                name,
+                FailedMacro::Attr(&args),
+                &body,
+                rules,
+            );
             cx.trace_macros_diag();
             Err(guar)
         }
@@ -522,6 +596,7 @@ pub(super) fn try_match_macro_attr<'matcher, T: Tracker<'matcher>>(
         match result {
             Success(body_named_matches) => {
                 psess.gated_spans.merge(gated_spans_snapshot);
+                #[allow(rustc::potential_query_instability)]
                 named_matches.extend(body_named_matches);
                 return Ok((i, rule, named_matches));
             }
@@ -536,6 +611,44 @@ pub(super) fn try_match_macro_attr<'matcher, T: Tracker<'matcher>>(
     Err(CanRetry::Yes)
 }
 
+/// Try expanding the macro derive. Returns the index of the successful arm and its
+/// named_matches if it was successful, and nothing if it failed. On failure, it's the caller's job
+/// to use `track` accordingly to record all errors correctly.
+#[instrument(level = "debug", skip(psess, body, rules, track), fields(tracking = %T::description()))]
+pub(super) fn try_match_macro_derive<'matcher, T: Tracker<'matcher>>(
+    psess: &ParseSess,
+    name: Ident,
+    body: &TokenStream,
+    rules: &'matcher [MacroRule],
+    track: &mut T,
+) -> Result<(usize, &'matcher MacroRule, NamedMatches), CanRetry> {
+    // This uses the same strategy as `try_match_macro`
+    let body_parser = parser_from_cx(psess, body.clone(), T::recovery());
+    let mut tt_parser = TtParser::new(name);
+    for (i, rule) in rules.iter().enumerate() {
+        let MacroRule::Derive { body, .. } = rule else { continue };
+
+        let mut gated_spans_snapshot = mem::take(&mut *psess.gated_spans.spans.borrow_mut());
+
+        let result = tt_parser.parse_tt(&mut Cow::Borrowed(&body_parser), body, track);
+        track.after_arm(true, &result);
+
+        match result {
+            Success(named_matches) => {
+                psess.gated_spans.merge(gated_spans_snapshot);
+                return Ok((i, rule, named_matches));
+            }
+            Failure(_) => {
+                mem::swap(&mut gated_spans_snapshot, &mut psess.gated_spans.spans.borrow_mut())
+            }
+            Error(_, _) => return Err(CanRetry::Yes),
+            ErrorReported(guar) => return Err(CanRetry::No(guar)),
+        }
+    }
+
+    Err(CanRetry::Yes)
+}
+
 /// Converts a macro item into a syntax extension.
 pub fn compile_declarative_macro(
     sess: &Session,
@@ -569,7 +682,7 @@ pub fn compile_declarative_macro(
     let mut rules = Vec::new();
 
     while p.token != token::Eof {
-        let args = if p.eat_keyword_noexpect(sym::attr) {
+        let (args, is_derive) = if p.eat_keyword_noexpect(sym::attr) {
             kinds |= MacroKinds::ATTR;
             if !features.macro_attr() {
                 feature_err(sess, sym::macro_attr, span, "`macro_rules!` attributes are unstable")
@@ -579,16 +692,46 @@ pub fn compile_declarative_macro(
                 return dummy_syn_ext(guar);
             }
             let args = p.parse_token_tree();
-            check_args_parens(sess, &args);
+            check_args_parens(sess, sym::attr, &args);
             let args = parse_one_tt(args, RulePart::Pattern, sess, node_id, features, edition);
             check_emission(check_lhs(sess, node_id, &args));
             if let Some(guar) = check_no_eof(sess, &p, "expected macro attr body") {
                 return dummy_syn_ext(guar);
             }
-            Some(args)
+            (Some(args), false)
+        } else if p.eat_keyword_noexpect(sym::derive) {
+            kinds |= MacroKinds::DERIVE;
+            let derive_keyword_span = p.prev_token.span;
+            if !features.macro_derive() {
+                feature_err(sess, sym::macro_attr, span, "`macro_rules!` derives are unstable")
+                    .emit();
+            }
+            if let Some(guar) = check_no_eof(sess, &p, "expected `()` after `derive`") {
+                return dummy_syn_ext(guar);
+            }
+            let args = p.parse_token_tree();
+            check_args_parens(sess, sym::derive, &args);
+            let args_empty_result = check_args_empty(sess, &args);
+            let args_not_empty = args_empty_result.is_err();
+            check_emission(args_empty_result);
+            if let Some(guar) = check_no_eof(sess, &p, "expected macro derive body") {
+                return dummy_syn_ext(guar);
+            }
+            // If the user has `=>` right after the `()`, they might have forgotten the empty
+            // parentheses.
+            if p.token == token::FatArrow {
+                let mut err = sess
+                    .dcx()
+                    .struct_span_err(p.token.span, "expected macro derive body, got `=>`");
+                if args_not_empty {
+                    err.span_label(derive_keyword_span, "need `()` after this `derive`");
+                }
+                return dummy_syn_ext(err.emit());
+            }
+            (None, true)
         } else {
             kinds |= MacroKinds::BANG;
-            None
+            (None, false)
         };
         let lhs_tt = p.parse_token_tree();
         let lhs_tt = parse_one_tt(lhs_tt, RulePart::Pattern, sess, node_id, features, edition);
@@ -619,6 +762,8 @@ pub fn compile_declarative_macro(
             let args = mbe::macro_parser::compute_locs(&delimited.tts);
             let body_span = lhs_span;
             rules.push(MacroRule::Attr { args, args_span, body: lhs, body_span, rhs: rhs_tt });
+        } else if is_derive {
+            rules.push(MacroRule::Derive { body: lhs, body_span: lhs_span, rhs: rhs_tt });
         } else {
             rules.push(MacroRule::Func { lhs, lhs_span, rhs: rhs_tt });
         }
@@ -665,7 +810,7 @@ fn check_no_eof(sess: &Session, p: &Parser<'_>, msg: &'static str) -> Option<Err
     None
 }
 
-fn check_args_parens(sess: &Session, args: &tokenstream::TokenTree) {
+fn check_args_parens(sess: &Session, rule_kw: Symbol, args: &tokenstream::TokenTree) {
     // This does not handle the non-delimited case; that gets handled separately by `check_lhs`.
     if let tokenstream::TokenTree::Delimited(dspan, _, delim, _) = args
         && *delim != Delimiter::Parenthesis
@@ -673,10 +818,21 @@ fn check_args_parens(sess: &Session, args: &tokenstream::TokenTree) {
         sess.dcx().emit_err(errors::MacroArgsBadDelim {
             span: dspan.entire(),
             sugg: errors::MacroArgsBadDelimSugg { open: dspan.open, close: dspan.close },
+            rule_kw,
         });
     }
 }
 
+fn check_args_empty(sess: &Session, args: &tokenstream::TokenTree) -> Result<(), ErrorGuaranteed> {
+    match args {
+        tokenstream::TokenTree::Delimited(.., delimited) if delimited.is_empty() => Ok(()),
+        _ => {
+            let msg = "`derive` rules do not accept arguments; `derive` must be followed by `()`";
+            Err(sess.dcx().span_err(args.span(), msg))
+        }
+    }
+}
+
 fn check_lhs(sess: &Session, node_id: NodeId, lhs: &mbe::TokenTree) -> Result<(), ErrorGuaranteed> {
     let e1 = check_lhs_nt_follows(sess, node_id, lhs);
     let e2 = check_lhs_no_empty_seq(sess, slice::from_ref(lhs));

compiler/rustc_feature/src/builtin_attrs.rs

@@ -6,6 +6,7 @@ use AttributeDuplicates::*;
 use AttributeGate::*;
 use AttributeType::*;
 use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::AttrStyle;
 use rustc_hir::attrs::EncodeCrossCrate;
 use rustc_span::edition::Edition;
 use rustc_span::{Symbol, sym};
@@ -132,9 +133,12 @@ pub struct AttributeTemplate {
 }
 
 impl AttributeTemplate {
-    pub fn suggestions(&self, inner: bool, name: impl std::fmt::Display) -> Vec<String> {
+    pub fn suggestions(&self, style: AttrStyle, name: impl std::fmt::Display) -> Vec<String> {
         let mut suggestions = vec![];
-        let inner = if inner { "!" } else { "" };
+        let inner = match style {
+            AttrStyle::Outer => "",
+            AttrStyle::Inner => "!",
+        };
         if self.word {
             suggestions.push(format!("#{inner}[{name}]"));
         }
@@ -741,9 +745,8 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         ErrorPreceding, EncodeCrossCrate::No
     ),
     gated!(
-        no_sanitize, Normal,
-        template!(List: &["address, kcfi, memory, thread"]), DuplicatesOk,
-        EncodeCrossCrate::No, experimental!(no_sanitize)
+        sanitize, Normal, template!(List: &[r#"address = "on|off""#, r#"kernel_address = "on|off""#, r#"cfi = "on|off""#, r#"hwaddress = "on|off""#, r#"kcfi = "on|off""#, r#"memory = "on|off""#, r#"memtag = "on|off""#, r#"shadow_call_stack = "on|off""#, r#"thread = "on|off""#]), ErrorPreceding,
+        EncodeCrossCrate::No, sanitize, experimental!(sanitize),
     ),
     gated!(
         coverage, Normal, template!(OneOf: &[sym::off, sym::on]),

compiler/rustc_feature/src/removed.rs

@@ -190,6 +190,9 @@ declare_features! (
     (removed, no_coverage, "1.74.0", Some(84605), Some("renamed to `coverage_attribute`"), 114656),
     /// Allows `#[no_debug]`.
     (removed, no_debug, "1.43.0", Some(29721), Some("removed due to lack of demand"), 69667),
+    // Allows the use of `no_sanitize` attribute.
+    /// The feature was renamed to `sanitize` and the attribute to `#[sanitize(xyz = "on|off")]`
+    (removed, no_sanitize, "CURRENT_RUSTC_VERSION", Some(39699), Some(r#"renamed to sanitize(xyz = "on|off")"#), 142681),
     /// Note: this feature was previously recorded in a separate
     /// `STABLE_REMOVED` list because it, uniquely, was once stable but was
     /// then removed. But there was no utility storing it separately, so now

compiler/rustc_feature/src/unstable.rs

@@ -556,6 +556,8 @@ declare_features! (
     (incomplete, loop_match, "1.90.0", Some(132306)),
     /// Allow `macro_rules!` attribute rules
     (unstable, macro_attr, "CURRENT_RUSTC_VERSION", Some(83527)),
+    /// Allow `macro_rules!` derive rules
+    (unstable, macro_derive, "CURRENT_RUSTC_VERSION", Some(143549)),
     /// Give access to additional metadata about declarative macro meta-variables.
     (unstable, macro_metavar_expr, "1.61.0", Some(83527)),
     /// Provides a way to concatenate identifiers using metavariable expressions.
@@ -592,8 +594,6 @@ declare_features! (
     (unstable, new_range, "1.86.0", Some(123741)),
     /// Allows `#![no_core]`.
     (unstable, no_core, "1.3.0", Some(29639)),
-    /// Allows the use of `no_sanitize` attribute.
-    (unstable, no_sanitize, "1.42.0", Some(39699)),
     /// Allows using the `non_exhaustive_omitted_patterns` lint.
     (unstable, non_exhaustive_omitted_patterns_lint, "1.57.0", Some(89554)),
     /// Allows `for<T>` binders in where-clauses
@@ -626,6 +626,8 @@ declare_features! (
     (unstable, return_type_notation, "1.70.0", Some(109417)),
     /// Allows `extern "rust-cold"`.
     (unstable, rust_cold_cc, "1.63.0", Some(97544)),
+    /// Allows the use of the `sanitize` attribute.
+    (unstable, sanitize, "CURRENT_RUSTC_VERSION", Some(39699)),
     /// Allows the use of SIMD types in functions declared in `extern` blocks.
     (unstable, simd_ffi, "1.0.0", Some(27731)),
     /// Allows specialization of implementations (RFC 1210).

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -205,6 +205,22 @@ pub enum Linkage {
     WeakODR,
 }
 
+#[derive(Clone, Copy, Decodable, Debug, Encodable, PartialEq)]
+#[derive(HashStable_Generic, PrintAttribute)]
+pub enum MirDialect {
+    Analysis,
+    Built,
+    Runtime,
+}
+
+#[derive(Clone, Copy, Decodable, Debug, Encodable, PartialEq)]
+#[derive(HashStable_Generic, PrintAttribute)]
+pub enum MirPhase {
+    Initial,
+    PostCleanup,
+    Optimized,
+}
+
 /// Represents parsed *built-in* inert attributes.
 ///
 /// ## Overview
@@ -324,6 +340,9 @@ pub enum AttributeKind {
     /// Represents `#[coverage(..)]`.
     Coverage(Span, CoverageAttrKind),
 
+    /// Represents `#[custom_mir]`.
+    CustomMir(Option<(MirDialect, Span)>, Option<(MirPhase, Span)>, Span),
+
     ///Represents `#[rustc_deny_explicit_impl]`.
     DenyExplicitImpl(Span),
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -31,6 +31,7 @@ impl AttributeKind {
             ConstTrait(..) => No,
             Coroutine(..) => No,
             Coverage(..) => No,
+            CustomMir(_, _, _) => Yes,
             DenyExplicitImpl(..) => No,
             Deprecation { .. } => Yes,
             DoNotImplementViaObject(..) => No,

compiler/rustc_hir_typeck/src/expr.rs

@@ -290,6 +290,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             | ExprKind::Let(..)
             | ExprKind::Loop(..)
             | ExprKind::Match(..) => {}
+            // Do not warn on `as` casts from never to any,
+            // they are sometimes required to appeal typeck.
+            ExprKind::Cast(_, _) => {}
             // If `expr` is a result of desugaring the try block and is an ok-wrapped
             // diverging expression (e.g. it arose from desugaring of `try { return }`),
             // we skip issuing a warning because it is autogenerated code.

compiler/rustc_infer/src/infer/mod.rs

@@ -782,22 +782,30 @@ impl<'tcx> InferCtxt<'tcx> {
         self.inner.borrow_mut().type_variables().num_vars()
     }
 
+    pub fn next_ty_vid(&self, span: Span) -> TyVid {
+        self.next_ty_vid_with_origin(TypeVariableOrigin { span, param_def_id: None })
+    }
+
+    pub fn next_ty_vid_with_origin(&self, origin: TypeVariableOrigin) -> TyVid {
+        self.inner.borrow_mut().type_variables().new_var(self.universe(), origin)
+    }
+
+    pub fn next_ty_vid_in_universe(&self, span: Span, universe: ty::UniverseIndex) -> TyVid {
+        let origin = TypeVariableOrigin { span, param_def_id: None };
+        self.inner.borrow_mut().type_variables().new_var(universe, origin)
+    }
+
     pub fn next_ty_var(&self, span: Span) -> Ty<'tcx> {
         self.next_ty_var_with_origin(TypeVariableOrigin { span, param_def_id: None })
     }
 
     pub fn next_ty_var_with_origin(&self, origin: TypeVariableOrigin) -> Ty<'tcx> {
-        let vid = self.inner.borrow_mut().type_variables().new_var(self.universe(), origin);
+        let vid = self.next_ty_vid_with_origin(origin);
         Ty::new_var(self.tcx, vid)
     }
 
-    pub fn next_ty_var_id_in_universe(&self, span: Span, universe: ty::UniverseIndex) -> TyVid {
-        let origin = TypeVariableOrigin { span, param_def_id: None };
-        self.inner.borrow_mut().type_variables().new_var(universe, origin)
-    }
-
     pub fn next_ty_var_in_universe(&self, span: Span, universe: ty::UniverseIndex) -> Ty<'tcx> {
-        let vid = self.next_ty_var_id_in_universe(span, universe);
+        let vid = self.next_ty_vid_in_universe(span, universe);
         Ty::new_var(self.tcx, vid)
     }
 

compiler/rustc_interface/src/interface.rs

@@ -285,7 +285,9 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
                     .expecteds
                     .entry(name.name)
                     .and_modify(|v| match v {
-                        ExpectedValues::Some(v) if !values_any_specified => {
+                        ExpectedValues::Some(v) if !values_any_specified =>
+                        {
+                            #[allow(rustc::potential_query_instability)]
                             v.extend(values.clone())
                         }
                         ExpectedValues::Some(_) => *v = ExpectedValues::Any,

compiler/rustc_interface/src/tests.rs

@@ -807,6 +807,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(hint_mostly_unused, true);
     tracked!(human_readable_cgu_names, true);
     tracked!(incremental_ignore_spans, true);
+    tracked!(indirect_branch_cs_prefix, true);
     tracked!(inline_mir, Some(true));
     tracked!(inline_mir_hint_threshold, Some(123));
     tracked!(inline_mir_threshold, Some(123));

compiler/rustc_lint/src/foreign_modules.rs

@@ -179,7 +179,7 @@ impl ClashingExternDeclarations {
 /// symbol's name.
 fn name_of_extern_decl(tcx: TyCtxt<'_>, fi: hir::OwnerId) -> SymbolName {
     if let Some((overridden_link_name, overridden_link_name_span)) =
-        tcx.codegen_fn_attrs(fi).link_name.map(|overridden_link_name| {
+        tcx.codegen_fn_attrs(fi).symbol_name.map(|overridden_link_name| {
             // FIXME: Instead of searching through the attributes again to get span
             // information, we could have codegen_fn_attrs also give span information back for
             // where the attribute was defined. However, until this is found to be a

compiler/rustc_lint/src/internal.rs

@@ -1,10 +1,10 @@
 //! Some lints that are only useful in the compiler or crates that use compiler internals, such as
 //! Clippy.
 
-use rustc_hir::HirId;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::{self, GenericArgsRef, Ty as MiddleTy};
+use rustc_hir::{Expr, ExprKind, HirId};
+use rustc_middle::ty::{self, ClauseKind, GenericArgsRef, PredicatePolarity, TraitPredicate, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::{Span, sym};
@@ -56,25 +56,6 @@ impl LateLintPass<'_> for DefaultHashTypes {
     }
 }
 
-/// Helper function for lints that check for expressions with calls and use typeck results to
-/// get the `DefId` and `GenericArgsRef` of the function.
-fn typeck_results_of_method_fn<'tcx>(
-    cx: &LateContext<'tcx>,
-    expr: &hir::Expr<'_>,
-) -> Option<(Span, DefId, ty::GenericArgsRef<'tcx>)> {
-    match expr.kind {
-        hir::ExprKind::MethodCall(segment, ..)
-            if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) =>
-        {
-            Some((segment.ident.span, def_id, cx.typeck_results().node_args(expr.hir_id)))
-        }
-        _ => match cx.typeck_results().node_type(expr.hir_id).kind() {
-            &ty::FnDef(def_id, args) => Some((expr.span, def_id, args)),
-            _ => None,
-        },
-    }
-}
-
 declare_tool_lint! {
     /// The `potential_query_instability` lint detects use of methods which can lead to
     /// potential query instability, such as iterating over a `HashMap`.
@@ -101,10 +82,12 @@ declare_tool_lint! {
 
 declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY, UNTRACKED_QUERY_INFORMATION]);
 
-impl LateLintPass<'_> for QueryStability {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
-        let Some((span, def_id, args)) = typeck_results_of_method_fn(cx, expr) else { return };
-        if let Ok(Some(instance)) = ty::Instance::try_resolve(cx.tcx, cx.typing_env(), def_id, args)
+impl<'tcx> LateLintPass<'tcx> for QueryStability {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
+        if let Some((callee_def_id, span, generic_args, _recv, _args)) =
+            get_callee_span_generic_args_and_args(cx, expr)
+            && let Ok(Some(instance)) =
+                ty::Instance::try_resolve(cx.tcx, cx.typing_env(), callee_def_id, generic_args)
         {
             let def_id = instance.def_id();
             if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) {
@@ -113,7 +96,15 @@ impl LateLintPass<'_> for QueryStability {
                     span,
                     QueryInstability { query: cx.tcx.item_name(def_id) },
                 );
+            } else if has_unstable_into_iter_predicate(cx, callee_def_id, generic_args) {
+                let call_span = span.with_hi(expr.span.hi());
+                cx.emit_span_lint(
+                    POTENTIAL_QUERY_INSTABILITY,
+                    call_span,
+                    QueryInstability { query: sym::into_iter },
+                );
             }
+
             if cx.tcx.has_attr(def_id, sym::rustc_lint_untracked_query_information) {
                 cx.emit_span_lint(
                     UNTRACKED_QUERY_INFORMATION,
@@ -125,6 +116,64 @@ impl LateLintPass<'_> for QueryStability {
     }
 }
 
+fn has_unstable_into_iter_predicate<'tcx>(
+    cx: &LateContext<'tcx>,
+    callee_def_id: DefId,
+    generic_args: GenericArgsRef<'tcx>,
+) -> bool {
+    let Some(into_iterator_def_id) = cx.tcx.get_diagnostic_item(sym::IntoIterator) else {
+        return false;
+    };
+    let Some(into_iter_fn_def_id) = cx.tcx.lang_items().into_iter_fn() else {
+        return false;
+    };
+    let predicates = cx.tcx.predicates_of(callee_def_id).instantiate(cx.tcx, generic_args);
+    for (predicate, _) in predicates {
+        let ClauseKind::Trait(TraitPredicate { trait_ref, polarity: PredicatePolarity::Positive }) =
+            predicate.kind().skip_binder()
+        else {
+            continue;
+        };
+        // Does the function or method require any of its arguments to implement `IntoIterator`?
+        if trait_ref.def_id != into_iterator_def_id {
+            continue;
+        }
+        let Ok(Some(instance)) =
+            ty::Instance::try_resolve(cx.tcx, cx.typing_env(), into_iter_fn_def_id, trait_ref.args)
+        else {
+            continue;
+        };
+        // Does the input type's `IntoIterator` implementation have the
+        // `rustc_lint_query_instability` attribute on its `into_iter` method?
+        if cx.tcx.has_attr(instance.def_id(), sym::rustc_lint_query_instability) {
+            return true;
+        }
+    }
+    false
+}
+
+/// Checks whether an expression is a function or method call and, if so, returns its `DefId`,
+/// `Span`, `GenericArgs`, and arguments. This is a slight augmentation of a similarly named Clippy
+/// function, `get_callee_generic_args_and_args`.
+fn get_callee_span_generic_args_and_args<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'tcx>,
+) -> Option<(DefId, Span, GenericArgsRef<'tcx>, Option<&'tcx Expr<'tcx>>, &'tcx [Expr<'tcx>])> {
+    if let ExprKind::Call(callee, args) = expr.kind
+        && let callee_ty = cx.typeck_results().expr_ty(callee)
+        && let ty::FnDef(callee_def_id, generic_args) = callee_ty.kind()
+    {
+        return Some((*callee_def_id, callee.span, generic_args, None, args));
+    }
+    if let ExprKind::MethodCall(segment, recv, args, _) = expr.kind
+        && let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
+    {
+        let generic_args = cx.typeck_results().node_args(expr.hir_id);
+        return Some((method_def_id, segment.ident.span, generic_args, Some(recv), args));
+    }
+    None
+}
+
 declare_tool_lint! {
     /// The `usage_of_ty_tykind` lint detects usages of `ty::TyKind::<kind>`,
     /// where `ty::<kind>` would suffice.
@@ -461,33 +510,22 @@ declare_tool_lint! {
 declare_lint_pass!(Diagnostics => [UNTRANSLATABLE_DIAGNOSTIC, DIAGNOSTIC_OUTSIDE_OF_IMPL]);
 
 impl LateLintPass<'_> for Diagnostics {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
+    fn check_expr<'tcx>(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
         let collect_args_tys_and_spans = |args: &[hir::Expr<'_>], reserve_one_extra: bool| {
             let mut result = Vec::with_capacity(args.len() + usize::from(reserve_one_extra));
             result.extend(args.iter().map(|arg| (cx.typeck_results().expr_ty(arg), arg.span)));
             result
         };
         // Only check function calls and method calls.
-        let (span, def_id, fn_gen_args, arg_tys_and_spans) = match expr.kind {
-            hir::ExprKind::Call(callee, args) => {
-                match cx.typeck_results().node_type(callee.hir_id).kind() {
-                    &ty::FnDef(def_id, fn_gen_args) => {
-                        (callee.span, def_id, fn_gen_args, collect_args_tys_and_spans(args, false))
-                    }
-                    _ => return, // occurs for fns passed as args
-                }
-            }
-            hir::ExprKind::MethodCall(_segment, _recv, args, _span) => {
-                let Some((span, def_id, fn_gen_args)) = typeck_results_of_method_fn(cx, expr)
-                else {
-                    return;
-                };
-                let mut args = collect_args_tys_and_spans(args, true);
-                args.insert(0, (cx.tcx.types.self_param, _recv.span)); // dummy inserted for `self`
-                (span, def_id, fn_gen_args, args)
-            }
-            _ => return,
+        let Some((def_id, span, fn_gen_args, recv, args)) =
+            get_callee_span_generic_args_and_args(cx, expr)
+        else {
+            return;
         };
+        let mut arg_tys_and_spans = collect_args_tys_and_spans(args, recv.is_some());
+        if let Some(recv) = recv {
+            arg_tys_and_spans.insert(0, (cx.tcx.types.self_param, recv.span)); // dummy inserted for `self`
+        }
 
         Self::diagnostic_outside_of_impl(cx, span, expr.hir_id, def_id, fn_gen_args);
         Self::untranslatable_diagnostic(cx, def_id, &arg_tys_and_spans);
@@ -496,7 +534,7 @@ impl LateLintPass<'_> for Diagnostics {
 
 impl Diagnostics {
     // Is the type `{D,Subd}iagMessage`?
-    fn is_diag_message<'cx>(cx: &LateContext<'cx>, ty: MiddleTy<'cx>) -> bool {
+    fn is_diag_message<'cx>(cx: &LateContext<'cx>, ty: Ty<'cx>) -> bool {
         if let Some(adt_def) = ty.ty_adt_def()
             && let Some(name) = cx.tcx.get_diagnostic_name(adt_def.did())
             && matches!(name, sym::DiagMessage | sym::SubdiagMessage)
@@ -510,7 +548,7 @@ impl Diagnostics {
     fn untranslatable_diagnostic<'cx>(
         cx: &LateContext<'cx>,
         def_id: DefId,
-        arg_tys_and_spans: &[(MiddleTy<'cx>, Span)],
+        arg_tys_and_spans: &[(Ty<'cx>, Span)],
     ) {
         let fn_sig = cx.tcx.fn_sig(def_id).instantiate_identity().skip_binder();
         let predicates = cx.tcx.predicates_of(def_id).instantiate_identity(cx.tcx).predicates;

compiler/rustc_lint_defs/src/builtin.rs

@@ -2301,18 +2301,18 @@ declare_lint! {
 
 declare_lint! {
     /// The `inline_no_sanitize` lint detects incompatible use of
-    /// [`#[inline(always)]`][inline] and [`#[no_sanitize(...)]`][no_sanitize].
+    /// [`#[inline(always)]`][inline] and [`#[sanitize(xyz = "off")]`][sanitize].
     ///
     /// [inline]: https://doc.rust-lang.org/reference/attributes/codegen.html#the-inline-attribute
-    /// [no_sanitize]: https://doc.rust-lang.org/nightly/unstable-book/language-features/no-sanitize.html
+    /// [sanitize]: https://doc.rust-lang.org/nightly/unstable-book/language-features/no-sanitize.html
     ///
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(no_sanitize)]
+    /// #![feature(sanitize)]
     ///
     /// #[inline(always)]
-    /// #[no_sanitize(address)]
+    /// #[sanitize(address = "off")]
     /// fn x() {}
     ///
     /// fn main() {
@@ -2325,11 +2325,11 @@ declare_lint! {
     /// ### Explanation
     ///
     /// The use of the [`#[inline(always)]`][inline] attribute prevents the
-    /// the [`#[no_sanitize(...)]`][no_sanitize] attribute from working.
+    /// the [`#[sanitize(xyz = "off")]`][sanitize] attribute from working.
     /// Consider temporarily removing `inline` attribute.
     pub INLINE_NO_SANITIZE,
     Warn,
-    "detects incompatible use of `#[inline(always)]` and `#[no_sanitize(...)]`",
+    r#"detects incompatible use of `#[inline(always)]` and `#[sanitize(... = "off")]`"#,
 }
 
 declare_lint! {

compiler/rustc_llvm/build.rs

@@ -226,7 +226,6 @@ fn main() {
     rerun_if_changed_anything_in_dir(Path::new("llvm-wrapper"));
     cfg.file("llvm-wrapper/PassWrapper.cpp")
         .file("llvm-wrapper/RustWrapper.cpp")
-        .file("llvm-wrapper/ArchiveWrapper.cpp")
         .file("llvm-wrapper/CoverageMappingWrapper.cpp")
         .file("llvm-wrapper/SymbolWrapper.cpp")
         .file("llvm-wrapper/Linker.cpp")

compiler/rustc_llvm/llvm-wrapper/ArchiveWrapper.cpp

@@ -1,208 +0,0 @@
-#include "LLVMWrapper.h"
-
-#include "llvm/Object/Archive.h"
-#include "llvm/Object/ArchiveWriter.h"
-#include "llvm/Support/Path.h"
-
-using namespace llvm;
-using namespace llvm::object;
-
-struct RustArchiveMember {
-  const char *Filename;
-  const char *Name;
-  Archive::Child Child;
-
-  RustArchiveMember()
-      : Filename(nullptr), Name(nullptr), Child(nullptr, nullptr, nullptr) {}
-  ~RustArchiveMember() {}
-};
-
-struct RustArchiveIterator {
-  bool First;
-  Archive::child_iterator Cur;
-  Archive::child_iterator End;
-  std::unique_ptr<Error> Err;
-
-  RustArchiveIterator(Archive::child_iterator Cur, Archive::child_iterator End,
-                      std::unique_ptr<Error> Err)
-      : First(true), Cur(Cur), End(End), Err(std::move(Err)) {}
-};
-
-enum class LLVMRustArchiveKind {
-  GNU,
-  BSD,
-  DARWIN,
-  COFF,
-  AIX_BIG,
-};
-
-static Archive::Kind fromRust(LLVMRustArchiveKind Kind) {
-  switch (Kind) {
-  case LLVMRustArchiveKind::GNU:
-    return Archive::K_GNU;
-  case LLVMRustArchiveKind::BSD:
-    return Archive::K_BSD;
-  case LLVMRustArchiveKind::DARWIN:
-    return Archive::K_DARWIN;
-  case LLVMRustArchiveKind::COFF:
-    return Archive::K_COFF;
-  case LLVMRustArchiveKind::AIX_BIG:
-    return Archive::K_AIXBIG;
-  default:
-    report_fatal_error("Bad ArchiveKind.");
-  }
-}
-
-typedef OwningBinary<Archive> *LLVMRustArchiveRef;
-typedef RustArchiveMember *LLVMRustArchiveMemberRef;
-typedef Archive::Child *LLVMRustArchiveChildRef;
-typedef Archive::Child const *LLVMRustArchiveChildConstRef;
-typedef RustArchiveIterator *LLVMRustArchiveIteratorRef;
-
-extern "C" LLVMRustArchiveRef LLVMRustOpenArchive(char *Path) {
-  ErrorOr<std::unique_ptr<MemoryBuffer>> BufOr = MemoryBuffer::getFile(
-      Path, /*IsText*/ false, /*RequiresNullTerminator=*/false);
-  if (!BufOr) {
-    LLVMRustSetLastError(BufOr.getError().message().c_str());
-    return nullptr;
-  }
-
-  Expected<std::unique_ptr<Archive>> ArchiveOr =
-      Archive::create(BufOr.get()->getMemBufferRef());
-
-  if (!ArchiveOr) {
-    LLVMRustSetLastError(toString(ArchiveOr.takeError()).c_str());
-    return nullptr;
-  }
-
-  OwningBinary<Archive> *Ret = new OwningBinary<Archive>(
-      std::move(ArchiveOr.get()), std::move(BufOr.get()));
-
-  return Ret;
-}
-
-extern "C" void LLVMRustDestroyArchive(LLVMRustArchiveRef RustArchive) {
-  delete RustArchive;
-}
-
-extern "C" LLVMRustArchiveIteratorRef
-LLVMRustArchiveIteratorNew(LLVMRustArchiveRef RustArchive) {
-  Archive *Archive = RustArchive->getBinary();
-  std::unique_ptr<Error> Err = std::make_unique<Error>(Error::success());
-  auto Cur = Archive->child_begin(*Err);
-  if (*Err) {
-    LLVMRustSetLastError(toString(std::move(*Err)).c_str());
-    return nullptr;
-  }
-  auto End = Archive->child_end();
-  return new RustArchiveIterator(Cur, End, std::move(Err));
-}
-
-extern "C" LLVMRustArchiveChildConstRef
-LLVMRustArchiveIteratorNext(LLVMRustArchiveIteratorRef RAI) {
-  if (RAI->Cur == RAI->End)
-    return nullptr;
-
-  // Advancing the iterator validates the next child, and this can
-  // uncover an error. LLVM requires that we check all Errors,
-  // so we only advance the iterator if we actually need to fetch
-  // the next child.
-  // This means we must not advance the iterator in the *first* call,
-  // but instead advance it *before* fetching the child in all later calls.
-  if (!RAI->First) {
-    ++RAI->Cur;
-    if (*RAI->Err) {
-      LLVMRustSetLastError(toString(std::move(*RAI->Err)).c_str());
-      return nullptr;
-    }
-  } else {
-    RAI->First = false;
-  }
-
-  if (RAI->Cur == RAI->End)
-    return nullptr;
-
-  const Archive::Child &Child = *RAI->Cur.operator->();
-  Archive::Child *Ret = new Archive::Child(Child);
-
-  return Ret;
-}
-
-extern "C" void LLVMRustArchiveChildFree(LLVMRustArchiveChildRef Child) {
-  delete Child;
-}
-
-extern "C" void LLVMRustArchiveIteratorFree(LLVMRustArchiveIteratorRef RAI) {
-  delete RAI;
-}
-
-extern "C" const char *
-LLVMRustArchiveChildName(LLVMRustArchiveChildConstRef Child, size_t *Size) {
-  Expected<StringRef> NameOrErr = Child->getName();
-  if (!NameOrErr) {
-    // rustc_codegen_llvm currently doesn't use this error string, but it might
-    // be useful in the future, and in the meantime this tells LLVM that the
-    // error was not ignored and that it shouldn't abort the process.
-    LLVMRustSetLastError(toString(NameOrErr.takeError()).c_str());
-    return nullptr;
-  }
-  StringRef Name = NameOrErr.get();
-  *Size = Name.size();
-  return Name.data();
-}
-
-extern "C" LLVMRustArchiveMemberRef
-LLVMRustArchiveMemberNew(char *Filename, char *Name,
-                         LLVMRustArchiveChildRef Child) {
-  RustArchiveMember *Member = new RustArchiveMember;
-  Member->Filename = Filename;
-  Member->Name = Name;
-  if (Child)
-    Member->Child = *Child;
-  return Member;
-}
-
-extern "C" void LLVMRustArchiveMemberFree(LLVMRustArchiveMemberRef Member) {
-  delete Member;
-}
-
-extern "C" LLVMRustResult LLVMRustWriteArchive(
-    char *Dst, size_t NumMembers, const LLVMRustArchiveMemberRef *NewMembers,
-    bool WriteSymbtab, LLVMRustArchiveKind RustKind, bool isEC) {
-
-  std::vector<NewArchiveMember> Members;
-  auto Kind = fromRust(RustKind);
-
-  for (size_t I = 0; I < NumMembers; I++) {
-    auto Member = NewMembers[I];
-    assert(Member->Name);
-    if (Member->Filename) {
-      Expected<NewArchiveMember> MOrErr =
-          NewArchiveMember::getFile(Member->Filename, true);
-      if (!MOrErr) {
-        LLVMRustSetLastError(toString(MOrErr.takeError()).c_str());
-        return LLVMRustResult::Failure;
-      }
-      MOrErr->MemberName = sys::path::filename(MOrErr->MemberName);
-      Members.push_back(std::move(*MOrErr));
-    } else {
-      Expected<NewArchiveMember> MOrErr =
-          NewArchiveMember::getOldMember(Member->Child, true);
-      if (!MOrErr) {
-        LLVMRustSetLastError(toString(MOrErr.takeError()).c_str());
-        return LLVMRustResult::Failure;
-      }
-      Members.push_back(std::move(*MOrErr));
-    }
-  }
-
-  auto SymtabMode = WriteSymbtab ? SymtabWritingMode::NormalSymtab
-                                 : SymtabWritingMode::NoSymtab;
-  auto Result =
-      writeArchive(Dst, Members, SymtabMode, Kind, true, false, nullptr, isEC);
-  if (!Result)
-    return LLVMRustResult::Success;
-  LLVMRustSetLastError(toString(std::move(Result)).c_str());
-
-  return LLVMRustResult::Failure;
-}

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1460,60 +1460,6 @@ LLVMRustGetDiagInfoKind(LLVMDiagnosticInfoRef DI) {
   return toRust((DiagnosticKind)unwrap(DI)->getKind());
 }
 
-// This is kept distinct from LLVMGetTypeKind, because when
-// a new type kind is added, the Rust-side enum must be
-// updated or UB will result.
-extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
-  switch (unwrap(Ty)->getTypeID()) {
-  case Type::VoidTyID:
-    return LLVMVoidTypeKind;
-  case Type::HalfTyID:
-    return LLVMHalfTypeKind;
-  case Type::FloatTyID:
-    return LLVMFloatTypeKind;
-  case Type::DoubleTyID:
-    return LLVMDoubleTypeKind;
-  case Type::X86_FP80TyID:
-    return LLVMX86_FP80TypeKind;
-  case Type::FP128TyID:
-    return LLVMFP128TypeKind;
-  case Type::PPC_FP128TyID:
-    return LLVMPPC_FP128TypeKind;
-  case Type::LabelTyID:
-    return LLVMLabelTypeKind;
-  case Type::MetadataTyID:
-    return LLVMMetadataTypeKind;
-  case Type::IntegerTyID:
-    return LLVMIntegerTypeKind;
-  case Type::FunctionTyID:
-    return LLVMFunctionTypeKind;
-  case Type::StructTyID:
-    return LLVMStructTypeKind;
-  case Type::ArrayTyID:
-    return LLVMArrayTypeKind;
-  case Type::PointerTyID:
-    return LLVMPointerTypeKind;
-  case Type::FixedVectorTyID:
-    return LLVMVectorTypeKind;
-  case Type::TokenTyID:
-    return LLVMTokenTypeKind;
-  case Type::ScalableVectorTyID:
-    return LLVMScalableVectorTypeKind;
-  case Type::BFloatTyID:
-    return LLVMBFloatTypeKind;
-  case Type::X86_AMXTyID:
-    return LLVMX86_AMXTypeKind;
-  default: {
-    std::string error;
-    auto stream = llvm::raw_string_ostream(error);
-    stream << "Rust does not support the TypeID: " << unwrap(Ty)->getTypeID()
-           << " for the type: " << *unwrap(Ty);
-    stream.flush();
-    report_fatal_error(error.c_str());
-  }
-  }
-}
-
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(SMDiagnostic, LLVMSMDiagnosticRef)
 
 extern "C" LLVMSMDiagnosticRef LLVMRustGetSMDiagnostic(LLVMDiagnosticInfoRef DI,
@@ -1993,29 +1939,3 @@ extern "C" void LLVMRustSetNoSanitizeHWAddress(LLVMValueRef Global) {
   MD.NoHWAddress = true;
   GV.setSanitizerMetadata(MD);
 }
-
-enum class LLVMRustTailCallKind {
-  None = 0,
-  Tail = 1,
-  MustTail = 2,
-  NoTail = 3
-};
-
-extern "C" void LLVMRustSetTailCallKind(LLVMValueRef Call,
-                                        LLVMRustTailCallKind Kind) {
-  CallInst *CI = unwrap<CallInst>(Call);
-  switch (Kind) {
-  case LLVMRustTailCallKind::None:
-    CI->setTailCallKind(CallInst::TCK_None);
-    break;
-  case LLVMRustTailCallKind::Tail:
-    CI->setTailCallKind(CallInst::TCK_Tail);
-    break;
-  case LLVMRustTailCallKind::MustTail:
-    CI->setTailCallKind(CallInst::TCK_MustTail);
-    break;
-  case LLVMRustTailCallKind::NoTail:
-    CI->setTailCallKind(CallInst::TCK_NoTail);
-    break;
-  }
-}

compiler/rustc_macros/src/print_attribute.rs

@@ -4,7 +4,7 @@ use syn::spanned::Spanned;
 use syn::{Data, Fields, Ident};
 use synstructure::Structure;
 
-fn print_fields(name: &Ident, fields: &Fields) -> (TokenStream, TokenStream, TokenStream) {
+fn print_fields(name: &Ident, fields: &Fields) -> (TokenStream, TokenStream) {
     let string_name = name.to_string();
     let mut disps = vec![quote! {let mut __printed_anything = false;}];
 
@@ -43,7 +43,6 @@ fn print_fields(name: &Ident, fields: &Fields) -> (TokenStream, TokenStream, Tok
                     #(#disps)*
                     __p.word("}");
                 },
-                quote! { true },
             )
         }
         Fields::Unnamed(fields_unnamed) => {
@@ -76,10 +75,9 @@ fn print_fields(name: &Ident, fields: &Fields) -> (TokenStream, TokenStream, Tok
                     #(#disps)*
                     __p.pclose();
                 },
-                quote! { true },
             )
         }
-        Fields::Unit => (quote! {}, quote! { __p.word(#string_name) }, quote! { true }),
+        Fields::Unit => (quote! {}, quote! { __p.word(#string_name) }),
     }
 }
 
@@ -89,51 +87,33 @@ pub(crate) fn print_attribute(input: Structure<'_>) -> TokenStream {
     };
 
     // Must be applied to an enum type.
-    let (code, printed) = match &input.ast().data {
+    let code = match &input.ast().data {
         Data::Enum(e) => {
-            let (arms, printed) = e
+            let arms = e
                 .variants
                 .iter()
                 .map(|x| {
                     let ident = &x.ident;
-                    let (pat, code, printed) = print_fields(ident, &x.fields);
+                    let (pat, code) = print_fields(ident, &x.fields);
 
-                    (
-                        quote! {
-                            Self::#ident #pat => {#code}
-                        },
-                        quote! {
-                            Self::#ident #pat => {#printed}
-                        },
-                    )
+                    quote! {
+                        Self::#ident #pat => {#code}
+                    }
                 })
-                .unzip::<_, _, Vec<_>, Vec<_>>();
+                .collect::<Vec<_>>();
 
-            (
-                quote! {
-                    match self {
-                        #(#arms)*
-                    }
-                },
-                quote! {
-                    match self {
-                        #(#printed)*
-                    }
-                },
-            )
+            quote! {
+                match self {
+                    #(#arms)*
+                }
+            }
         }
         Data::Struct(s) => {
-            let (pat, code, printed) = print_fields(&input.ast().ident, &s.fields);
-            (
-                quote! {
-                    let Self #pat = self;
-                    #code
-                },
-                quote! {
-                    let Self #pat = self;
-                    #printed
-                },
-            )
+            let (pat, code) = print_fields(&input.ast().ident, &s.fields);
+            quote! {
+                let Self #pat = self;
+                #code
+            }
         }
         Data::Union(u) => {
             return span_error(u.union_token.span(), "can't derive PrintAttribute on unions");
@@ -144,7 +124,7 @@ pub(crate) fn print_attribute(input: Structure<'_>) -> TokenStream {
     input.gen_impl(quote! {
         #[allow(unused)]
         gen impl PrintAttribute for @Self {
-            fn should_render(&self) -> bool { #printed }
+            fn should_render(&self) -> bool { true }
             fn print_attribute(&self, __p: &mut rustc_ast_pretty::pp::Printer) { #code }
         }
     })

compiler/rustc_metadata/src/creader.rs

@@ -32,6 +32,7 @@ use rustc_session::cstore::{CrateDepKind, CrateSource, ExternCrate, ExternCrateS
 use rustc_session::lint::{self, BuiltinLintDiag};
 use rustc_session::output::validate_crate_name;
 use rustc_session::search_paths::PathKind;
+use rustc_span::def_id::DefId;
 use rustc_span::edition::Edition;
 use rustc_span::{DUMMY_SP, Ident, Span, Symbol, sym};
 use rustc_target::spec::{PanicStrategy, Target};
@@ -275,6 +276,10 @@ impl CStore {
             .filter_map(|(cnum, data)| data.as_deref().map(|data| (cnum, data)))
     }
 
+    pub fn all_proc_macro_def_ids(&self) -> impl Iterator<Item = DefId> {
+        self.iter_crate_data().flat_map(|(krate, data)| data.proc_macros_for_crate(krate, self))
+    }
+
     fn push_dependencies_in_postorder(&self, deps: &mut IndexSet<CrateNum>, cnum: CrateNum) {
         if !deps.contains(&cnum) {
             let data = self.get_crate_data(cnum);

compiler/rustc_metadata/src/native_libs.rs

@@ -701,7 +701,7 @@ impl<'tcx> Collector<'tcx> {
             .link_ordinal
             .map_or(import_name_type, |ord| Some(PeImportNameType::Ordinal(ord)));
 
-        let name = codegen_fn_attrs.link_name.unwrap_or_else(|| self.tcx.item_name(item));
+        let name = codegen_fn_attrs.symbol_name.unwrap_or_else(|| self.tcx.item_name(item));
 
         if self.tcx.sess.target.binary_format == BinaryFormat::Elf {
             let name = name.as_str();

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -2014,6 +2014,22 @@ impl CrateMetadata {
         self.root.is_proc_macro_crate()
     }
 
+    pub(crate) fn proc_macros_for_crate(
+        &self,
+        krate: CrateNum,
+        cstore: &CStore,
+    ) -> impl Iterator<Item = DefId> {
+        gen move {
+            for def_id in self.root.proc_macro_data.as_ref().into_iter().flat_map(move |data| {
+                data.macros
+                    .decode(CrateMetadataRef { cdata: self, cstore })
+                    .map(move |index| DefId { index, krate })
+            }) {
+                yield def_id;
+            }
+        }
+    }
+
     pub(crate) fn name(&self) -> Symbol {
         self.root.header.name
     }

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -35,14 +35,10 @@ pub struct CodegenFnAttrs {
     pub inline: InlineAttr,
     /// Parsed representation of the `#[optimize]` attribute
     pub optimize: OptimizeAttr,
-    /// The `#[export_name = "..."]` attribute, indicating a custom symbol a
-    /// function should be exported under
-    pub export_name: Option<Symbol>,
-    /// The `#[link_name = "..."]` attribute, indicating a custom symbol an
-    /// imported function should be imported as. Note that `export_name`
-    /// probably isn't set when this is set, this is for foreign items while
-    /// `#[export_name]` is for Rust-defined functions.
-    pub link_name: Option<Symbol>,
+    /// The name this function will be imported/exported under. This can be set
+    /// using the `#[export_name = "..."]` or `#[link_name = "..."]` attribute
+    /// depending on if this is a function definition or foreign function.
+    pub symbol_name: Option<Symbol>,
     /// The `#[link_ordinal = "..."]` attribute, indicating an ordinal an
     /// imported function has in the dynamic library. Note that this must not
     /// be set when `link_name` is set. This is for foreign items with the
@@ -61,8 +57,8 @@ pub struct CodegenFnAttrs {
     /// The `#[link_section = "..."]` attribute, or what executable section this
     /// should be placed in.
     pub link_section: Option<Symbol>,
-    /// The `#[no_sanitize(...)]` attribute. Indicates sanitizers for which
-    /// instrumentation should be disabled inside the annotated function.
+    /// The `#[sanitize(xyz = "off")]` attribute. Indicates sanitizers for which
+    /// instrumentation should be disabled inside the function.
     pub no_sanitize: SanitizerSet,
     /// The `#[instruction_set(set)]` attribute. Indicates if the generated code should
     /// be generated against a specific instruction set. Only usable on architectures which allow
@@ -167,8 +163,7 @@ impl CodegenFnAttrs {
             flags: CodegenFnAttrFlags::empty(),
             inline: InlineAttr::None,
             optimize: OptimizeAttr::Default,
-            export_name: None,
-            link_name: None,
+            symbol_name: None,
             link_ordinal: None,
             target_features: vec![],
             safe_target_features: false,
@@ -196,7 +191,7 @@ impl CodegenFnAttrs {
 
         self.flags.contains(CodegenFnAttrFlags::NO_MANGLE)
             || self.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)
-            || self.export_name.is_some()
+            || self.symbol_name.is_some()
             || match self.linkage {
                 // These are private, so make sure we don't try to consider
                 // them external.

compiler/rustc_middle/src/mir/mod.rs

@@ -115,48 +115,6 @@ impl MirPhase {
             MirPhase::Runtime(runtime_phase) => (3, 1 + runtime_phase as usize),
         }
     }
-
-    /// Parses a `MirPhase` from a pair of strings. Panics if this isn't possible for any reason.
-    pub fn parse(dialect: String, phase: Option<String>) -> Self {
-        match &*dialect.to_ascii_lowercase() {
-            "built" => {
-                assert!(phase.is_none(), "Cannot specify a phase for `Built` MIR");
-                MirPhase::Built
-            }
-            "analysis" => Self::Analysis(AnalysisPhase::parse(phase)),
-            "runtime" => Self::Runtime(RuntimePhase::parse(phase)),
-            _ => bug!("Unknown MIR dialect: '{}'", dialect),
-        }
-    }
-}
-
-impl AnalysisPhase {
-    pub fn parse(phase: Option<String>) -> Self {
-        let Some(phase) = phase else {
-            return Self::Initial;
-        };
-
-        match &*phase.to_ascii_lowercase() {
-            "initial" => Self::Initial,
-            "post_cleanup" | "post-cleanup" | "postcleanup" => Self::PostCleanup,
-            _ => bug!("Unknown analysis phase: '{}'", phase),
-        }
-    }
-}
-
-impl RuntimePhase {
-    pub fn parse(phase: Option<String>) -> Self {
-        let Some(phase) = phase else {
-            return Self::Initial;
-        };
-
-        match &*phase.to_ascii_lowercase() {
-            "initial" => Self::Initial,
-            "post_cleanup" | "post-cleanup" | "postcleanup" => Self::PostCleanup,
-            "optimized" => Self::Optimized,
-            _ => bug!("Unknown runtime phase: '{}'", phase),
-        }
-    }
 }
 
 /// Where a specific `mir::Body` comes from.

compiler/rustc_middle/src/mir/pretty.rs

@@ -929,7 +929,10 @@ impl<'tcx> TerminatorKind<'tcx> {
             }
             Yield { value, resume_arg, .. } => write!(fmt, "{resume_arg:?} = yield({value:?})"),
             Unreachable => write!(fmt, "unreachable"),
-            Drop { place, .. } => write!(fmt, "drop({place:?})"),
+            Drop { place, async_fut: None, .. } => write!(fmt, "drop({place:?})"),
+            Drop { place, async_fut: Some(async_fut), .. } => {
+                write!(fmt, "async drop({place:?}; poll={async_fut:?})")
+            }
             Call { func, args, destination, .. } => {
                 write!(fmt, "{destination:?} = ")?;
                 write!(fmt, "{func:?}(")?;

compiler/rustc_middle/src/mir/visit.rs

@@ -531,13 +531,20 @@ macro_rules! make_mir_visitor {
                         unwind: _,
                         replace: _,
                         drop: _,
-                        async_fut: _,
+                        async_fut,
                     } => {
                         self.visit_place(
                             place,
                             PlaceContext::MutatingUse(MutatingUseContext::Drop),
                             location
                         );
+                        if let Some(async_fut) = async_fut {
+                            self.visit_local(
+                                $(&$mutability)? *async_fut,
+                                PlaceContext::MutatingUse(MutatingUseContext::Borrow),
+                                location
+                            );
+                        }
                     }
 
                     TerminatorKind::Call {

compiler/rustc_middle/src/query/erase.rs

@@ -343,6 +343,7 @@ trivial! {
     rustc_span::Symbol,
     rustc_span::Ident,
     rustc_target::spec::PanicStrategy,
+    rustc_target::spec::SanitizerSet,
     rustc_type_ir::Variance,
     u32,
     usize,

compiler/rustc_middle/src/query/mod.rs

@@ -100,7 +100,7 @@ use rustc_session::lint::LintExpectationId;
 use rustc_span::def_id::LOCAL_CRATE;
 use rustc_span::source_map::Spanned;
 use rustc_span::{DUMMY_SP, Span, Symbol};
-use rustc_target::spec::PanicStrategy;
+use rustc_target::spec::{PanicStrategy, SanitizerSet};
 use {rustc_abi as abi, rustc_ast as ast, rustc_hir as hir};
 
 use crate::infer::canonical::{self, Canonical};
@@ -2686,6 +2686,16 @@ rustc_queries! {
         desc { |tcx| "looking up anon const kind of `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern
     }
+
+    /// Checks for the nearest `#[sanitize(xyz = "off")]` or
+    /// `#[sanitize(xyz = "on")]` on this def and any enclosing defs, up to the
+    /// crate root.
+    ///
+    /// Returns the set of sanitizers that is explicitly disabled for this def.
+    query disabled_sanitizers_for(key: LocalDefId) -> SanitizerSet {
+        desc { |tcx| "checking what set of sanitizers are enabled on `{}`", tcx.def_path_str(key) }
+        feedable
+    }
 }
 
 rustc_with_all_queries! { define_callbacks! }

compiler/rustc_middle/src/query/on_disk_cache.rs

@@ -645,34 +645,29 @@ impl<'a, 'tcx> SpanDecoder for CacheDecoder<'a, 'tcx> {
         let parent = Option::<LocalDefId>::decode(self);
         let tag: u8 = Decodable::decode(self);
 
-        if tag == TAG_PARTIAL_SPAN {
-            return Span::new(BytePos(0), BytePos(0), ctxt, parent);
-        } else if tag == TAG_RELATIVE_SPAN {
-            let dlo = u32::decode(self);
-            let dto = u32::decode(self);
+        let (lo, hi) = match tag {
+            TAG_PARTIAL_SPAN => (BytePos(0), BytePos(0)),
+            TAG_RELATIVE_SPAN => {
+                let dlo = u32::decode(self);
+                let dto = u32::decode(self);
 
-            let enclosing = self.tcx.source_span_untracked(parent.unwrap()).data_untracked();
-            let span = Span::new(
-                enclosing.lo + BytePos::from_u32(dlo),
-                enclosing.lo + BytePos::from_u32(dto),
-                ctxt,
-                parent,
-            );
+                let enclosing = self.tcx.source_span_untracked(parent.unwrap()).data_untracked();
+                (enclosing.lo + BytePos::from_u32(dlo), enclosing.lo + BytePos::from_u32(dto))
+            }
+            TAG_FULL_SPAN => {
+                let file_lo_index = SourceFileIndex::decode(self);
+                let line_lo = usize::decode(self);
+                let col_lo = RelativeBytePos::decode(self);
+                let len = BytePos::decode(self);
 
-            return span;
-        } else {
-            debug_assert_eq!(tag, TAG_FULL_SPAN);
-        }
-
-        let file_lo_index = SourceFileIndex::decode(self);
-        let line_lo = usize::decode(self);
-        let col_lo = RelativeBytePos::decode(self);
-        let len = BytePos::decode(self);
-
-        let file_lo = self.file_index_to_file(file_lo_index);
-        let lo = file_lo.lines()[line_lo - 1] + col_lo;
-        let lo = file_lo.absolute_position(lo);
-        let hi = lo + len;
+                let file_lo = self.file_index_to_file(file_lo_index);
+                let lo = file_lo.lines()[line_lo - 1] + col_lo;
+                let lo = file_lo.absolute_position(lo);
+                let hi = lo + len;
+                (lo, hi)
+            }
+            _ => unreachable!(),
+        };
 
         Span::new(lo, hi, ctxt, parent)
     }

compiler/rustc_mir_build/src/builder/custom/mod.rs

@@ -19,10 +19,10 @@
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{Attribute, HirId};
+use rustc_hir::{HirId, attrs};
 use rustc_index::{IndexSlice, IndexVec};
+use rustc_middle::bug;
 use rustc_middle::mir::*;
-use rustc_middle::span_bug;
 use rustc_middle::thir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
@@ -39,7 +39,8 @@ pub(super) fn build_custom_mir<'tcx>(
     return_ty: Ty<'tcx>,
     return_ty_span: Span,
     span: Span,
-    attr: &Attribute,
+    dialect: Option<attrs::MirDialect>,
+    phase: Option<attrs::MirPhase>,
 ) -> Body<'tcx> {
     let mut body = Body {
         basic_blocks: BasicBlocks::new(IndexVec::new()),
@@ -72,7 +73,7 @@ pub(super) fn build_custom_mir<'tcx>(
         inlined_parent_scope: None,
         local_data: ClearCrossCrate::Set(SourceScopeLocalData { lint_root: hir_id }),
     });
-    body.injection_phase = Some(parse_attribute(attr));
+    body.injection_phase = Some(parse_attribute(dialect, phase));
 
     let mut pctxt = ParseCtxt {
         tcx,
@@ -98,40 +99,38 @@ pub(super) fn build_custom_mir<'tcx>(
     body
 }
 
-fn parse_attribute(attr: &Attribute) -> MirPhase {
-    let meta_items = attr.meta_item_list().unwrap();
-    let mut dialect: Option<String> = None;
-    let mut phase: Option<String> = None;
-
-    // Not handling errors properly for this internal attribute; will just abort on errors.
-    for nested in meta_items {
-        let name = nested.name().unwrap();
-        let value = nested.value_str().unwrap().as_str().to_string();
-        match name.as_str() {
-            "dialect" => {
-                assert!(dialect.is_none());
-                dialect = Some(value);
-            }
-            "phase" => {
-                assert!(phase.is_none());
-                phase = Some(value);
-            }
-            other => {
-                span_bug!(
-                    nested.span(),
-                    "Unexpected key while parsing custom_mir attribute: '{}'",
-                    other
-                );
-            }
-        }
-    }
-
+/// Turns the arguments passed to `#[custom_mir(..)]` into a proper
+/// [`MirPhase`]. Panics if this isn't possible for any reason.
+fn parse_attribute(dialect: Option<attrs::MirDialect>, phase: Option<attrs::MirPhase>) -> MirPhase {
     let Some(dialect) = dialect else {
+        // Caught during attribute checking.
         assert!(phase.is_none());
         return MirPhase::Built;
     };
 
-    MirPhase::parse(dialect, phase)
+    match dialect {
+        attrs::MirDialect::Built => {
+            // Caught during attribute checking.
+            assert!(phase.is_none(), "Cannot specify a phase for `Built` MIR");
+            MirPhase::Built
+        }
+        attrs::MirDialect::Analysis => match phase {
+            None | Some(attrs::MirPhase::Initial) => MirPhase::Analysis(AnalysisPhase::Initial),
+
+            Some(attrs::MirPhase::PostCleanup) => MirPhase::Analysis(AnalysisPhase::PostCleanup),
+
+            Some(attrs::MirPhase::Optimized) => {
+                // Caught during attribute checking.
+                bug!("`optimized` dialect is not compatible with the `analysis` dialect")
+            }
+        },
+
+        attrs::MirDialect::Runtime => match phase {
+            None | Some(attrs::MirPhase::Initial) => MirPhase::Runtime(RuntimePhase::Initial),
+            Some(attrs::MirPhase::PostCleanup) => MirPhase::Runtime(RuntimePhase::PostCleanup),
+            Some(attrs::MirPhase::Optimized) => MirPhase::Runtime(RuntimePhase::Optimized),
+        },
+    }
 }
 
 struct ParseCtxt<'a, 'tcx> {

compiler/rustc_mir_build/src/builder/mod.rs

@@ -11,9 +11,10 @@ use rustc_ast::attr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sorted_map::SortedIndexMultiMap;
 use rustc_errors::ErrorGuaranteed;
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::{self as hir, BindingMode, ByRef, HirId, ItemLocalId, Node};
+use rustc_hir::{self as hir, BindingMode, ByRef, HirId, ItemLocalId, Node, find_attr};
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
@@ -479,8 +480,7 @@ fn construct_fn<'tcx>(
         ty => span_bug!(span_with_body, "unexpected type of body: {ty:?}"),
     };
 
-    if let Some(custom_mir_attr) =
-        tcx.hir_attrs(fn_id).iter().find(|attr| attr.has_name(sym::custom_mir))
+    if let Some((dialect, phase)) = find_attr!(tcx.hir_attrs(fn_id), AttributeKind::CustomMir(dialect, phase, _) => (dialect, phase))
     {
         return custom::build_custom_mir(
             tcx,
@@ -492,7 +492,8 @@ fn construct_fn<'tcx>(
             return_ty,
             return_ty_span,
             span_with_body,
-            custom_mir_attr,
+            dialect.as_ref().map(|(d, _)| *d),
+            phase.as_ref().map(|(p, _)| *p),
         );
     }
 

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -5,8 +5,9 @@ use std::ops::Bound;
 use rustc_ast::AsmMacro;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::DiagArgValue;
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::DefKind;
-use rustc_hir::{self as hir, BindingMode, ByRef, HirId, Mutability};
+use rustc_hir::{self as hir, BindingMode, ByRef, HirId, Mutability, find_attr};
 use rustc_middle::middle::codegen_fn_attrs::TargetFeature;
 use rustc_middle::mir::BorrowKind;
 use rustc_middle::span_bug;
@@ -1157,7 +1158,7 @@ pub(crate) fn check_unsafety(tcx: TyCtxt<'_>, def: LocalDefId) {
     // Closures and inline consts are handled by their owner, if it has a body
     assert!(!tcx.is_typeck_child(def.to_def_id()));
     // Also, don't safety check custom MIR
-    if tcx.has_attr(def, sym::custom_mir) {
+    if find_attr!(tcx.get_all_attrs(def), AttributeKind::CustomMir(..) => ()).is_some() {
         return;
     }
 

compiler/rustc_mir_build/src/thir/cx/mod.rs

@@ -4,11 +4,11 @@
 
 use rustc_data_structures::steal::Steal;
 use rustc_errors::ErrorGuaranteed;
-use rustc_hir as hir;
-use rustc_hir::HirId;
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
+use rustc_hir::{self as hir, HirId, find_attr};
 use rustc_middle::bug;
 use rustc_middle::middle::region;
 use rustc_middle::thir::*;
@@ -111,10 +111,8 @@ impl<'tcx> ThirBuildCx<'tcx> {
             typeck_results,
             rvalue_scopes: &typeck_results.rvalue_scopes,
             body_owner: def.to_def_id(),
-            apply_adjustments: tcx
-                .hir_attrs(hir_id)
-                .iter()
-                .all(|attr| !attr.has_name(rustc_span::sym::custom_mir)),
+            apply_adjustments:
+                !find_attr!(tcx.hir_attrs(hir_id), AttributeKind::CustomMir(..) => ()).is_some(),
         }
     }
 

compiler/rustc_next_trait_solver/src/canonicalizer.rs

@@ -27,7 +27,7 @@ enum CanonicalizeInputKind {
     ParamEnv,
     /// When canonicalizing predicates, we don't keep `'static`. If we're
     /// currently outside of the trait solver and canonicalize the root goal
-    /// during HIR typeck, we replace each occurance of a region with a
+    /// during HIR typeck, we replace each occurrence of a region with a
     /// unique region variable. See the comment on `InferCtxt::in_hir_typeck`
     /// for more details.
     Predicate { is_hir_typeck_root_goal: bool },

compiler/rustc_next_trait_solver/src/solve/trait_goals.rs

@@ -6,8 +6,8 @@ use rustc_type_ir::inherent::*;
 use rustc_type_ir::lang_items::TraitSolverLangItem;
 use rustc_type_ir::solve::{CanonicalResponse, SizedTraitKind};
 use rustc_type_ir::{
-    self as ty, Interner, Movability, TraitPredicate, TraitRef, TypeVisitableExt as _, TypingMode,
-    Upcast as _, elaborate,
+    self as ty, Interner, Movability, PredicatePolarity, TraitPredicate, TraitRef,
+    TypeVisitableExt as _, TypingMode, Upcast as _, elaborate,
 };
 use tracing::{debug, instrument, trace};
 
@@ -133,19 +133,26 @@ where
             cx: I,
             clause_def_id: I::DefId,
             goal_def_id: I::DefId,
+            polarity: PredicatePolarity,
         ) -> bool {
             clause_def_id == goal_def_id
             // PERF(sized-hierarchy): Sizedness supertraits aren't elaborated to improve perf, so
             // check for a `MetaSized` supertrait being matched against a `Sized` assumption.
             //
             // `PointeeSized` bounds are syntactic sugar for a lack of bounds so don't need this.
-                || (cx.is_lang_item(clause_def_id, TraitSolverLangItem::Sized)
+                || (polarity == PredicatePolarity::Positive
+                    && cx.is_lang_item(clause_def_id, TraitSolverLangItem::Sized)
                     && cx.is_lang_item(goal_def_id, TraitSolverLangItem::MetaSized))
         }
 
         if let Some(trait_clause) = assumption.as_trait_clause()
             && trait_clause.polarity() == goal.predicate.polarity
-            && trait_def_id_matches(ecx.cx(), trait_clause.def_id(), goal.predicate.def_id())
+            && trait_def_id_matches(
+                ecx.cx(),
+                trait_clause.def_id(),
+                goal.predicate.def_id(),
+                goal.predicate.polarity,
+            )
             && DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
                 goal.predicate.trait_ref.args,
                 trait_clause.skip_binder().trait_ref.args,
@@ -168,6 +175,8 @@ where
         // PERF(sized-hierarchy): Sizedness supertraits aren't elaborated to improve perf, so
         // check for a `Sized` subtrait when looking for `MetaSized`. `PointeeSized` bounds
         // are syntactic sugar for a lack of bounds so don't need this.
+        // We don't need to check polarity, `fast_reject_assumption` already rejected non-`Positive`
+        // polarity `Sized` assumptions as matching non-`Positive` `MetaSized` goals.
         if ecx.cx().is_lang_item(goal.predicate.def_id(), TraitSolverLangItem::MetaSized)
             && ecx.cx().is_lang_item(trait_clause.def_id(), TraitSolverLangItem::Sized)
         {

compiler/rustc_parse/messages.ftl

@@ -748,9 +748,6 @@ parse_parentheses_with_struct_fields = invalid `struct` delimiters or `fn` call
     .suggestion_braces_for_struct = if `{$type}` is a struct, use braces as delimiters
     .suggestion_no_fields_for_fn = if `{$type}` is a function, use the arguments directly
 
-parse_parenthesized_lifetime = parenthesized lifetime bounds are not supported
-parse_parenthesized_lifetime_suggestion = remove the parentheses
-
 parse_path_double_colon = path separator must be a double colon
     .suggestion = use a double colon instead
 

compiler/rustc_parse/src/errors.rs

@@ -3163,27 +3163,6 @@ pub(crate) struct ModifierLifetime {
     pub modifier: &'static str,
 }
 
-#[derive(Subdiagnostic)]
-#[multipart_suggestion(
-    parse_parenthesized_lifetime_suggestion,
-    applicability = "machine-applicable"
-)]
-pub(crate) struct RemoveParens {
-    #[suggestion_part(code = "")]
-    pub lo: Span,
-    #[suggestion_part(code = "")]
-    pub hi: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(parse_parenthesized_lifetime)]
-pub(crate) struct ParenthesizedLifetime {
-    #[primary_span]
-    pub span: Span,
-    #[subdiagnostic]
-    pub sugg: RemoveParens,
-}
-
 #[derive(Diagnostic)]
 #[diag(parse_underscore_literal_suffix)]
 pub(crate) struct UnderscoreLiteralSuffix {

compiler/rustc_parse/src/lexer/mod.rs

@@ -49,6 +49,7 @@ pub(crate) fn lex_token_trees<'psess, 'src>(
     mut src: &'src str,
     mut start_pos: BytePos,
     override_span: Option<Span>,
+    frontmatter_allowed: FrontmatterAllowed,
 ) -> Result<TokenStream, Vec<Diag<'psess>>> {
     // Skip `#!`, if present.
     if let Some(shebang_len) = rustc_lexer::strip_shebang(src) {
@@ -56,7 +57,7 @@ pub(crate) fn lex_token_trees<'psess, 'src>(
         start_pos = start_pos + BytePos::from_usize(shebang_len);
     }
 
-    let cursor = Cursor::new(src, FrontmatterAllowed::Yes);
+    let cursor = Cursor::new(src, frontmatter_allowed);
     let mut lexer = Lexer {
         psess,
         start_pos,

compiler/rustc_parse/src/lib.rs

@@ -20,6 +20,7 @@ use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::{AttrItem, Attribute, MetaItemInner, token};
 use rustc_ast_pretty::pprust;
 use rustc_errors::{Diag, EmissionGuarantee, FatalError, PResult, pluralize};
+use rustc_lexer::FrontmatterAllowed;
 use rustc_session::parse::ParseSess;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{FileName, SourceFile, Span};
@@ -146,7 +147,7 @@ fn new_parser_from_source_file(
     source_file: Arc<SourceFile>,
 ) -> Result<Parser<'_>, Vec<Diag<'_>>> {
     let end_pos = source_file.end_position();
-    let stream = source_file_to_stream(psess, source_file, None)?;
+    let stream = source_file_to_stream(psess, source_file, None, FrontmatterAllowed::Yes)?;
     let mut parser = Parser::new(psess, stream, None);
     if parser.token == token::Eof {
         parser.token.span = Span::new(end_pos, end_pos, parser.token.span.ctxt(), None);
@@ -161,7 +162,9 @@ pub fn source_str_to_stream(
     override_span: Option<Span>,
 ) -> Result<TokenStream, Vec<Diag<'_>>> {
     let source_file = psess.source_map().new_source_file(name, source);
-    source_file_to_stream(psess, source_file, override_span)
+    // used mainly for `proc_macro` and the likes, not for our parsing purposes, so don't parse
+    // frontmatters as frontmatters.
+    source_file_to_stream(psess, source_file, override_span, FrontmatterAllowed::No)
 }
 
 /// Given a source file, produces a sequence of token trees. Returns any buffered errors from
@@ -170,6 +173,7 @@ fn source_file_to_stream<'psess>(
     psess: &'psess ParseSess,
     source_file: Arc<SourceFile>,
     override_span: Option<Span>,
+    frontmatter_allowed: FrontmatterAllowed,
 ) -> Result<TokenStream, Vec<Diag<'psess>>> {
     let src = source_file.src.as_ref().unwrap_or_else(|| {
         psess.dcx().bug(format!(
@@ -178,7 +182,13 @@ fn source_file_to_stream<'psess>(
         ));
     });
 
-    lexer::lex_token_trees(psess, src.as_str(), source_file.start_pos, override_span)
+    lexer::lex_token_trees(
+        psess,
+        src.as_str(),
+        source_file.start_pos,
+        override_span,
+        frontmatter_allowed,
+    )
 }
 
 /// Runs the given subparser `f` on the tokens of the given `attr`'s item.

compiler/rustc_parse/src/parser/expr.rs

@@ -2397,12 +2397,12 @@ impl<'a> Parser<'a> {
         let before = self.prev_token;
         let binder = if self.check_keyword(exp!(For)) {
             let lo = self.token.span;
-            let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?;
+            let (bound_vars, _) = self.parse_higher_ranked_binder()?;
             let span = lo.to(self.prev_token.span);
 
             self.psess.gated_spans.gate(sym::closure_lifetime_binder, span);
 
-            ClosureBinder::For { span, generic_params: lifetime_defs }
+            ClosureBinder::For { span, generic_params: bound_vars }
         } else {
             ClosureBinder::NotPresent
         };

compiler/rustc_parse/src/parser/generics.rs

@@ -172,8 +172,11 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parses a (possibly empty) list of lifetime and type parameters, possibly including
-    /// a trailing comma and erroneous trailing attributes.
+    /// Parse a (possibly empty) list of generic (lifetime, type, const) parameters.
+    ///
+    /// ```ebnf
+    /// GenericParams = (GenericParam ("," GenericParam)* ","?)?
+    /// ```
     pub(super) fn parse_generic_params(&mut self) -> PResult<'a, ThinVec<ast::GenericParam>> {
         let mut params = ThinVec::new();
         let mut done = false;
@@ -520,7 +523,7 @@ impl<'a> Parser<'a> {
         // * `for<'a> Trait1<'a>: Trait2<'a /* ok */>`
         // * `(for<'a> Trait1<'a>): Trait2<'a /* not ok */>`
         // * `for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /* ok */, 'b /* not ok */>`
-        let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?;
+        let (bound_vars, _) = self.parse_higher_ranked_binder()?;
 
         // Parse type with mandatory colon and (possibly empty) bounds,
         // or with mandatory equality sign and the second type.
@@ -528,7 +531,7 @@ impl<'a> Parser<'a> {
         if self.eat(exp!(Colon)) {
             let bounds = self.parse_generic_bounds()?;
             Ok(ast::WherePredicateKind::BoundPredicate(ast::WhereBoundPredicate {
-                bound_generic_params: lifetime_defs,
+                bound_generic_params: bound_vars,
                 bounded_ty: ty,
                 bounds,
             }))

compiler/rustc_parse/src/parser/ty.rs

@@ -308,11 +308,11 @@ impl<'a> Parser<'a> {
             // Function pointer type or bound list (trait object type) starting with a poly-trait.
             //   `for<'lt> [unsafe] [extern "ABI"] fn (&'lt S) -> T`
             //   `for<'lt> Trait1<'lt> + Trait2 + 'a`
-            let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?;
+            let (bound_vars, _) = self.parse_higher_ranked_binder()?;
             if self.check_fn_front_matter(false, Case::Sensitive) {
                 self.parse_ty_fn_ptr(
                     lo,
-                    lifetime_defs,
+                    bound_vars,
                     Some(self.prev_token.span.shrink_to_lo()),
                     recover_return_sign,
                 )?
@@ -326,7 +326,7 @@ impl<'a> Parser<'a> {
                     let path = self.parse_path(PathStyle::Type)?;
                     let parse_plus = allow_plus == AllowPlus::Yes && self.check_plus();
                     let kind = self.parse_remaining_bounds_path(
-                        lifetime_defs,
+                        bound_vars,
                         path,
                         lo,
                         parse_plus,
@@ -359,7 +359,7 @@ impl<'a> Parser<'a> {
                     let path = self.parse_path(PathStyle::Type)?;
                     let parse_plus = allow_plus == AllowPlus::Yes && self.check_plus();
                     self.parse_remaining_bounds_path(
-                        lifetime_defs,
+                        bound_vars,
                         path,
                         lo,
                         parse_plus,
@@ -443,7 +443,7 @@ impl<'a> Parser<'a> {
             let ty = ts.into_iter().next().unwrap();
             let maybe_bounds = allow_plus == AllowPlus::Yes && self.token.is_like_plus();
             match ty.kind {
-                // `(TY_BOUND_NOPAREN) + BOUND + ...`.
+                // `"(" BareTraitBound ")" "+" Bound "+" ...`.
                 TyKind::Path(None, path) if maybe_bounds => self.parse_remaining_bounds_path(
                     ThinVec::new(),
                     path,
@@ -853,10 +853,13 @@ impl<'a> Parser<'a> {
         Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds))
     }
 
-    fn parse_precise_capturing_args(
-        &mut self,
-    ) -> PResult<'a, (ThinVec<PreciseCapturingArg>, Span)> {
-        let lo = self.token.span;
+    /// Parse a use-bound aka precise capturing list.
+    ///
+    /// ```ebnf
+    /// UseBound = "use" "<" (PreciseCapture ("," PreciseCapture)* ","?)? ">"
+    /// PreciseCapture = "Self" | Ident | Lifetime
+    /// ```
+    fn parse_use_bound(&mut self, lo: Span, parens: ast::Parens) -> PResult<'a, GenericBound> {
         self.expect_lt()?;
         let (args, _, _) = self.parse_seq_to_before_tokens(
             &[exp!(Gt)],
@@ -882,7 +885,13 @@ impl<'a> Parser<'a> {
             },
         )?;
         self.expect_gt()?;
-        Ok((args, lo.to(self.prev_token.span)))
+
+        if let ast::Parens::Yes = parens {
+            self.expect(exp!(CloseParen))?;
+            self.report_parenthesized_bound(lo, self.prev_token.span, "precise capturing lists");
+        }
+
+        Ok(GenericBound::Use(args, lo.to(self.prev_token.span)))
     }
 
     /// Is a `dyn B0 + ... + Bn` type allowed here?
@@ -940,9 +949,10 @@ impl<'a> Parser<'a> {
         self.parse_generic_bounds_common(AllowPlus::Yes)
     }
 
-    /// Parses bounds of a type parameter `BOUND + BOUND + ...`, possibly with trailing `+`.
+    /// Parse generic bounds.
     ///
-    /// See `parse_generic_bound` for the `BOUND` grammar.
+    /// Only if `allow_plus` this parses a `+`-separated list of bounds (trailing `+` is admitted).
+    /// Otherwise, this only parses a single bound or none.
     fn parse_generic_bounds_common(&mut self, allow_plus: AllowPlus) -> PResult<'a, GenericBounds> {
         let mut bounds = Vec::new();
 
@@ -988,48 +998,56 @@ impl<'a> Parser<'a> {
             || self.check_keyword(exp!(Use))
     }
 
-    /// Parses a bound according to the grammar:
+    /// Parse a bound.
+    ///
     /// ```ebnf
-    /// BOUND = TY_BOUND | LT_BOUND
+    /// Bound = LifetimeBound | UseBound | TraitBound
     /// ```
     fn parse_generic_bound(&mut self) -> PResult<'a, GenericBound> {
-        let lo = self.token.span;
         let leading_token = self.prev_token;
+        let lo = self.token.span;
+
+        // We only admit parenthesized *trait* bounds. However, we want to gracefully recover from
+        // other kinds of parenthesized bounds, so parse the opening parenthesis *here*.
+        //
+        // In the future we might want to lift this syntactic restriction and
+        // introduce "`GenericBound::Paren(Box<GenericBound>)`".
         let parens = if self.eat(exp!(OpenParen)) { ast::Parens::Yes } else { ast::Parens::No };
 
-        let bound = if self.token.is_lifetime() {
-            self.parse_generic_lt_bound(lo, parens)?
+        if self.token.is_lifetime() {
+            self.parse_lifetime_bound(lo, parens)
         } else if self.eat_keyword(exp!(Use)) {
-            // parse precise captures, if any. This is `use<'lt, 'lt, P, P>`; a list of
-            // lifetimes and ident params (including SelfUpper). These are validated later
-            // for order, duplication, and whether they actually reference params.
-            let use_span = self.prev_token.span;
-            let (args, args_span) = self.parse_precise_capturing_args()?;
-            GenericBound::Use(args, use_span.to(args_span))
+            self.parse_use_bound(lo, parens)
         } else {
-            self.parse_generic_ty_bound(lo, parens, &leading_token)?
-        };
-
-        Ok(bound)
+            self.parse_trait_bound(lo, parens, &leading_token)
+        }
     }
 
-    /// Parses a lifetime ("outlives") bound, e.g. `'a`, according to:
+    /// Parse a lifetime-bound aka outlives-bound.
+    ///
     /// ```ebnf
-    /// LT_BOUND = LIFETIME
+    /// LifetimeBound = Lifetime
     /// ```
-    fn parse_generic_lt_bound(
-        &mut self,
-        lo: Span,
-        parens: ast::Parens,
-    ) -> PResult<'a, GenericBound> {
+    fn parse_lifetime_bound(&mut self, lo: Span, parens: ast::Parens) -> PResult<'a, GenericBound> {
         let lt = self.expect_lifetime();
-        let bound = GenericBound::Outlives(lt);
+
         if let ast::Parens::Yes = parens {
-            // FIXME(Centril): Consider not erroring here and accepting `('lt)` instead,
-            // possibly introducing `GenericBound::Paren(Box<GenericBound>)`?
-            self.recover_paren_lifetime(lo)?;
+            self.expect(exp!(CloseParen))?;
+            self.report_parenthesized_bound(lo, self.prev_token.span, "lifetime bounds");
         }
-        Ok(bound)
+
+        Ok(GenericBound::Outlives(lt))
+    }
+
+    fn report_parenthesized_bound(&self, lo: Span, hi: Span, kind: &str) -> ErrorGuaranteed {
+        let mut diag =
+            self.dcx().struct_span_err(lo.to(hi), format!("{kind} may not be parenthesized"));
+        diag.multipart_suggestion(
+            "remove the parentheses",
+            vec![(lo, String::new()), (hi, String::new())],
+            Applicability::MachineApplicable,
+        );
+        diag.emit()
     }
 
     /// Emits an error if any trait bound modifiers were present.
@@ -1074,27 +1092,17 @@ impl<'a> Parser<'a> {
         unreachable!("lifetime bound intercepted in `parse_generic_ty_bound` but no modifiers?")
     }
 
-    /// Recover on `('lifetime)` with `(` already eaten.
-    fn recover_paren_lifetime(&mut self, lo: Span) -> PResult<'a, ()> {
-        self.expect(exp!(CloseParen))?;
-        let span = lo.to(self.prev_token.span);
-        let sugg = errors::RemoveParens { lo, hi: self.prev_token.span };
-
-        self.dcx().emit_err(errors::ParenthesizedLifetime { span, sugg });
-        Ok(())
-    }
-
     /// Parses the modifiers that may precede a trait in a bound, e.g. `?Trait` or `[const] Trait`.
     ///
     /// If no modifiers are present, this does not consume any tokens.
     ///
     /// ```ebnf
-    /// CONSTNESS = [["["] "const" ["]"]]
-    /// ASYNCNESS = ["async"]
-    /// POLARITY = ["?" | "!"]
+    /// Constness = ("const" | "[" "const" "]")?
+    /// Asyncness = "async"?
+    /// Polarity = ("?" | "!")?
     /// ```
     ///
-    /// See `parse_generic_ty_bound` for the complete grammar of trait bound modifiers.
+    /// See `parse_trait_bound` for more context.
     fn parse_trait_bound_modifiers(&mut self) -> PResult<'a, TraitBoundModifiers> {
         let modifier_lo = self.token.span;
         let constness = self.parse_bound_constness()?;
@@ -1187,20 +1195,21 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parses a type bound according to:
-    /// ```ebnf
-    /// TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
-    /// TY_BOUND_NOPAREN = [for<GENERIC_PARAMS> CONSTNESS ASYNCNESS | POLARITY] SIMPLE_PATH
-    /// ```
+    /// Parse a trait bound.
     ///
-    /// For example, this grammar accepts `for<'a: 'b> [const] ?m::Trait<'a>`.
-    fn parse_generic_ty_bound(
+    /// ```ebnf
+    /// TraitBound = BareTraitBound | "(" BareTraitBound ")"
+    /// BareTraitBound =
+    ///     (HigherRankedBinder Constness Asyncness | Polarity)
+    ///     TypePath
+    /// ```
+    fn parse_trait_bound(
         &mut self,
         lo: Span,
         parens: ast::Parens,
         leading_token: &Token,
     ) -> PResult<'a, GenericBound> {
-        let (mut lifetime_defs, binder_span) = self.parse_late_bound_lifetime_defs()?;
+        let (mut bound_vars, binder_span) = self.parse_higher_ranked_binder()?;
 
         let modifiers_lo = self.token.span;
         let modifiers = self.parse_trait_bound_modifiers()?;
@@ -1223,11 +1232,11 @@ impl<'a> Parser<'a> {
         // e.g. `T: for<'a> 'a` or `T: [const] 'a`.
         if self.token.is_lifetime() {
             let _: ErrorGuaranteed = self.error_lt_bound_with_modifiers(modifiers, binder_span);
-            return self.parse_generic_lt_bound(lo, parens);
+            return self.parse_lifetime_bound(lo, parens);
         }
 
-        if let (more_lifetime_defs, Some(binder_span)) = self.parse_late_bound_lifetime_defs()? {
-            lifetime_defs.extend(more_lifetime_defs);
+        if let (more_bound_vars, Some(binder_span)) = self.parse_higher_ranked_binder()? {
+            bound_vars.extend(more_bound_vars);
             self.dcx().emit_err(errors::BinderBeforeModifiers { binder_span, modifiers_span });
         }
 
@@ -1287,7 +1296,7 @@ impl<'a> Parser<'a> {
         };
 
         if self.may_recover() && self.token == TokenKind::OpenParen {
-            self.recover_fn_trait_with_lifetime_params(&mut path, &mut lifetime_defs)?;
+            self.recover_fn_trait_with_lifetime_params(&mut path, &mut bound_vars)?;
         }
 
         if let ast::Parens::Yes = parens {
@@ -1310,7 +1319,7 @@ impl<'a> Parser<'a> {
         }
 
         let poly_trait =
-            PolyTraitRef::new(lifetime_defs, path, modifiers, lo.to(self.prev_token.span), parens);
+            PolyTraitRef::new(bound_vars, path, modifiers, lo.to(self.prev_token.span), parens);
         Ok(GenericBound::Trait(poly_trait))
     }
 
@@ -1349,8 +1358,12 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Optionally parses `for<$generic_params>`.
-    pub(super) fn parse_late_bound_lifetime_defs(
+    /// Parse an optional higher-ranked binder.
+    ///
+    /// ```ebnf
+    /// HigherRankedBinder = ("for" "<" GenericParams ">")?
+    /// ```
+    pub(super) fn parse_higher_ranked_binder(
         &mut self,
     ) -> PResult<'a, (ThinVec<GenericParam>, Option<Span>)> {
         if self.eat_keyword(exp!(For)) {

compiler/rustc_passes/messages.ftl

@@ -74,6 +74,16 @@ passes_const_stable_not_stable =
     attribute `#[rustc_const_stable]` can only be applied to functions that are declared `#[stable]`
     .label = attribute specified here
 
+passes_custom_mir_incompatible_dialect_and_phase =
+    The {$dialect} dialect is not compatible with the {$phase} phase
+    .dialect_span = this dialect...
+    .phase_span = ... is not compatible with this phase
+
+passes_custom_mir_phase_requires_dialect =
+    `dialect` key required
+    .phase_span = `phase` argument requires a `dialect` argument
+
+
 passes_dead_codes =
     { $multiple ->
       *[true] multiple {$descr}s are
@@ -422,10 +432,6 @@ passes_must_not_suspend =
     `must_not_suspend` attribute should be applied to a struct, enum, union, or trait
     .label = is not a struct, enum, union, or trait
 
-passes_must_use_no_effect =
-    `#[must_use]` has no effect when applied to {$target}
-    .suggestion = remove the attribute
-
 passes_no_link =
     attribute should be applied to an `extern crate` item
     .label = not an `extern crate` item
@@ -444,10 +450,6 @@ passes_no_main_function =
     .teach_note = If you don't know the basics of Rust, you can go look to the Rust Book to get started: https://doc.rust-lang.org/book/
     .non_function_main = non-function item at `crate::main` is found
 
-passes_no_sanitize =
-    `#[no_sanitize({$attr_str})]` should be applied to {$accepted_kind}
-    .label = not {$accepted_kind}
-
 passes_non_exhaustive_with_default_field_values =
     `#[non_exhaustive]` can't be used to annotate items with default field values
     .label = this struct has default field values
@@ -542,6 +544,12 @@ passes_rustc_pub_transparent =
     attribute should be applied to `#[repr(transparent)]` types
     .label = not a `#[repr(transparent)]` type
 
+passes_sanitize_attribute_not_allowed =
+    sanitize attribute not allowed here
+    .not_fn_impl_mod = not a function, impl block, or module
+    .no_body = function has no body
+    .help = sanitize attribute can be applied to a function (with body), impl block, or module
+
 passes_should_be_applied_to_fn =
     attribute should be applied to a function definition
     .label = {$on_crate ->

compiler/rustc_passes/src/check_attr.rs

@@ -18,7 +18,7 @@ use rustc_feature::{
     ACCEPTED_LANG_FEATURES, AttributeDuplicates, AttributeType, BUILTIN_ATTRIBUTE_MAP,
     BuiltinAttribute,
 };
-use rustc_hir::attrs::{AttributeKind, InlineAttr, ReprAttr};
+use rustc_hir::attrs::{AttributeKind, InlineAttr, MirDialect, MirPhase, ReprAttr};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalModDefId;
 use rustc_hir::intravisit::{self, Visitor};
@@ -194,8 +194,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::MayDangle(attr_span)) => {
                     self.check_may_dangle(hir_id, *attr_span)
                 }
-                Attribute::Parsed(AttributeKind::MustUse { span, .. }) => {
-                    self.check_must_use(hir_id, *span, target)
+                &Attribute::Parsed(AttributeKind::CustomMir(dialect, phase, attr_span)) => {
+                    self.check_custom_mir(dialect, phase, attr_span)
                 }
                 Attribute::Parsed(
                     AttributeKind::BodyStability { .. }
@@ -246,9 +246,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::Coverage (..)
                     | AttributeKind::ShouldPanic { .. }
                     | AttributeKind::Coroutine(..)
-                    | AttributeKind::Linkage(..),
+                    | AttributeKind::Linkage(..)
+                    | AttributeKind::MustUse { .. },
                 ) => { /* do nothing  */ }
-
                 Attribute::Unparsed(attr_item) => {
                     style = Some(attr_item.style);
                     match attr.path().as_slice() {
@@ -258,8 +258,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::diagnostic, sym::on_unimplemented, ..] => {
                             self.check_diagnostic_on_unimplemented(attr.span(), hir_id, target)
                         }
-                        [sym::no_sanitize, ..] => {
-                            self.check_no_sanitize(attr, span, target)
+                        [sym::sanitize, ..] => {
+                            self.check_sanitize(attr, span, target)
                         }
                         [sym::thread_local, ..] => self.check_thread_local(attr, span, target),
                         [sym::doc, ..] => self.check_doc_attrs(
@@ -331,8 +331,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::panic_handler
                             | sym::lang
                             | sym::needs_allocator
-                            | sym::default_lib_allocator
-                            | sym::custom_mir,
+                            | sym::default_lib_allocator,
                             ..
                         ] => {}
                         [name, rest@..] => {
@@ -482,39 +481,43 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_no_sanitize(&self, attr: &Attribute, span: Span, target: Target) {
+    /// Checks that the `#[sanitize(..)]` attribute is applied to a
+    /// function/closure/method, or to an impl block or module.
+    fn check_sanitize(&self, attr: &Attribute, target_span: Span, target: Target) {
+        let mut not_fn_impl_mod = None;
+        let mut no_body = None;
+
         if let Some(list) = attr.meta_item_list() {
             for item in list.iter() {
-                let sym = item.name();
-                match sym {
-                    Some(s @ sym::address | s @ sym::hwaddress) => {
-                        let is_valid =
-                            matches!(target, Target::Fn | Target::Method(..) | Target::Static);
-                        if !is_valid {
-                            self.dcx().emit_err(errors::NoSanitize {
-                                attr_span: item.span(),
-                                defn_span: span,
-                                accepted_kind: "a function or static",
-                                attr_str: s.as_str(),
-                            });
-                        }
+                let MetaItemInner::MetaItem(set) = item else {
+                    return;
+                };
+                let segments = set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
+                match target {
+                    Target::Fn
+                    | Target::Closure
+                    | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent)
+                    | Target::Impl { .. }
+                    | Target::Mod => return,
+                    Target::Static if matches!(segments.as_slice(), [sym::address]) => return,
+
+                    // These are "functions", but they aren't allowed because they don't
+                    // have a body, so the usual explanation would be confusing.
+                    Target::Method(MethodKind::Trait { body: false }) | Target::ForeignFn => {
+                        no_body = Some(target_span);
                     }
+
                     _ => {
-                        let is_valid = matches!(target, Target::Fn | Target::Method(..));
-                        if !is_valid {
-                            self.dcx().emit_err(errors::NoSanitize {
-                                attr_span: item.span(),
-                                defn_span: span,
-                                accepted_kind: "a function",
-                                attr_str: &match sym {
-                                    Some(name) => name.to_string(),
-                                    None => "...".to_string(),
-                                },
-                            });
-                        }
+                        not_fn_impl_mod = Some(target_span);
                     }
                 }
             }
+            self.dcx().emit_err(errors::SanitizeAttributeNotAllowed {
+                attr_span: attr.span(),
+                not_fn_impl_mod,
+                no_body,
+                help: (),
+            });
         }
     }
 
@@ -561,7 +564,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             }
         }
     }
-
     /// Checks if `#[collapse_debuginfo]` is applied to a macro.
     fn check_collapse_debuginfo(&self, attr: &Attribute, span: Span, target: Target) {
         match target {
@@ -1259,41 +1261,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    /// Warns against some misuses of `#[must_use]`
-    fn check_must_use(&self, hir_id: HirId, attr_span: Span, target: Target) {
-        if matches!(
-            target,
-            Target::Fn
-                | Target::Enum
-                | Target::Struct
-                | Target::Union
-                | Target::Method(MethodKind::Trait { body: false } | MethodKind::Inherent)
-                | Target::ForeignFn
-                // `impl Trait` in return position can trip
-                // `unused_must_use` if `Trait` is marked as
-                // `#[must_use]`
-                | Target::Trait
-        ) {
-            return;
-        }
-
-        // `#[must_use]` can be applied to a trait method definition with a default body
-        if let Target::Method(MethodKind::Trait { body: true }) = target
-            && let parent_def_id = self.tcx.hir_get_parent_item(hir_id).def_id
-            && let containing_item = self.tcx.hir_expect_item(parent_def_id)
-            && let hir::ItemKind::Trait(..) = containing_item.kind
-        {
-            return;
-        }
-
-        self.tcx.emit_node_span_lint(
-            UNUSED_ATTRIBUTES,
-            hir_id,
-            attr_span,
-            errors::MustUseNoEffect { target: target.plural_name(), attr_span },
-        );
-    }
-
     /// Checks if `#[must_not_suspend]` is applied to a struct, enum, union, or trait.
     fn check_must_not_suspend(&self, attr: &Attribute, span: Span, target: Target) {
         match target {
@@ -2113,6 +2080,48 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             self.dcx().emit_err(errors::ConstContinueAttr { attr_span, node_span });
         };
     }
+
+    fn check_custom_mir(
+        &self,
+        dialect: Option<(MirDialect, Span)>,
+        phase: Option<(MirPhase, Span)>,
+        attr_span: Span,
+    ) {
+        let Some((dialect, dialect_span)) = dialect else {
+            if let Some((_, phase_span)) = phase {
+                self.dcx()
+                    .emit_err(errors::CustomMirPhaseRequiresDialect { attr_span, phase_span });
+            }
+            return;
+        };
+
+        match dialect {
+            MirDialect::Analysis => {
+                if let Some((MirPhase::Optimized, phase_span)) = phase {
+                    self.dcx().emit_err(errors::CustomMirIncompatibleDialectAndPhase {
+                        dialect,
+                        phase: MirPhase::Optimized,
+                        attr_span,
+                        dialect_span,
+                        phase_span,
+                    });
+                }
+            }
+
+            MirDialect::Built => {
+                if let Some((phase, phase_span)) = phase {
+                    self.dcx().emit_err(errors::CustomMirIncompatibleDialectAndPhase {
+                        dialect,
+                        phase,
+                        attr_span,
+                        dialect_span,
+                        phase_span,
+                    });
+                }
+            }
+            MirDialect::Runtime => {}
+        }
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {

compiler/rustc_passes/src/errors.rs

@@ -7,6 +7,7 @@ use rustc_errors::{
     MultiSpan, Subdiagnostic,
 };
 use rustc_hir::Target;
+use rustc_hir::attrs::{MirDialect, MirPhase};
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::{MainDefinition, Ty};
 use rustc_span::{DUMMY_SP, Span, Symbol};
@@ -357,14 +358,6 @@ pub(crate) struct BothFfiConstAndPure {
     pub attr_span: Span,
 }
 
-#[derive(LintDiagnostic)]
-#[diag(passes_must_use_no_effect)]
-pub(crate) struct MustUseNoEffect {
-    pub target: &'static str,
-    #[suggestion(code = "", applicability = "machine-applicable", style = "tool-only")]
-    pub attr_span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(passes_must_not_suspend)]
 pub(crate) struct MustNotSuspend {
@@ -1488,15 +1481,21 @@ pub(crate) struct AttrCrateLevelOnlySugg {
     pub attr: Span,
 }
 
+/// "sanitize attribute not allowed here"
 #[derive(Diagnostic)]
-#[diag(passes_no_sanitize)]
-pub(crate) struct NoSanitize<'a> {
+#[diag(passes_sanitize_attribute_not_allowed)]
+pub(crate) struct SanitizeAttributeNotAllowed {
     #[primary_span]
     pub attr_span: Span,
-    #[label]
-    pub defn_span: Span,
-    pub accepted_kind: &'a str,
-    pub attr_str: &'a str,
+    /// "not a function, impl block, or module"
+    #[label(passes_not_fn_impl_mod)]
+    pub not_fn_impl_mod: Option<Span>,
+    /// "function has no body"
+    #[label(passes_no_body)]
+    pub no_body: Option<Span>,
+    /// "sanitize attribute can be applied to a function (with body), impl block, or module"
+    #[help]
+    pub help: (),
 }
 
 // FIXME(jdonszelmann): move back to rustc_attr
@@ -1570,3 +1569,25 @@ pub(crate) struct ReprAlignShouldBeAlign {
     pub span: Span,
     pub item: &'static str,
 }
+
+#[derive(Diagnostic)]
+#[diag(passes_custom_mir_phase_requires_dialect)]
+pub(crate) struct CustomMirPhaseRequiresDialect {
+    #[primary_span]
+    pub attr_span: Span,
+    #[label]
+    pub phase_span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(passes_custom_mir_incompatible_dialect_and_phase)]
+pub(crate) struct CustomMirIncompatibleDialectAndPhase {
+    pub dialect: MirDialect,
+    pub phase: MirPhase,
+    #[primary_span]
+    pub attr_span: Span,
+    #[label]
+    pub dialect_span: Span,
+    #[label]
+    pub phase_span: Span,
+}

compiler/rustc_resolve/messages.ftl

@@ -93,6 +93,9 @@ resolve_consider_adding_a_derive =
 resolve_consider_adding_macro_export =
     consider adding a `#[macro_export]` to the macro in the imported module
 
+resolve_consider_marking_as_pub_crate =
+    in case you want to use the macro within this crate only, reduce the visibility to `pub(crate)`
+
 resolve_consider_declaring_with_pub =
     consider declaring type or module `{$ident}` with `pub`
 
@@ -249,7 +252,7 @@ resolve_macro_cannot_use_as_attr =
     `{$ident}` exists, but has no `attr` rules
 
 resolve_macro_cannot_use_as_derive =
-     `{$ident}` exists, but a declarative macro cannot be used as a derive macro
+     `{$ident}` exists, but has no `derive` rules
 
 resolve_macro_defined_later =
     a macro with the same name exists, but it appears later

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -210,6 +210,17 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
     }
 
+    /// Add every proc macro accessible from the current crate to the `macro_map` so diagnostics can
+    /// find them for suggestions.
+    pub(crate) fn register_macros_for_all_crates(&mut self) {
+        if !self.all_crate_macros_already_registered {
+            for def_id in self.cstore().all_proc_macro_def_ids() {
+                self.get_macro_by_def_id(def_id);
+            }
+            self.all_crate_macros_already_registered = true;
+        }
+    }
+
     pub(crate) fn build_reduced_graph(
         &mut self,
         fragment: &AstFragment,
@@ -474,6 +485,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
             root_span,
             root_id,
             vis,
+            vis_span: item.vis.span,
         });
 
         self.r.indeterminate_imports.push(import);
@@ -966,6 +978,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
             span: item.span,
             module_path: Vec::new(),
             vis,
+            vis_span: item.vis.span,
         });
         if used {
             self.r.import_use_map.insert(import, Used::Other);
@@ -1100,6 +1113,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
                 span,
                 module_path: Vec::new(),
                 vis: Visibility::Restricted(CRATE_DEF_ID),
+                vis_span: item.vis.span,
             })
         };
 
@@ -1270,6 +1284,7 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
                     span,
                     module_path: Vec::new(),
                     vis,
+                    vis_span: item.vis.span,
                 });
                 self.r.import_use_map.insert(import, Used::Other);
                 let import_binding = self.r.import(binding, import);

compiler/rustc_resolve/src/diagnostics.rs

@@ -1469,33 +1469,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         krate: &Crate,
         sugg_span: Option<Span>,
     ) {
-        // Bring imported but unused `derive` macros into `macro_map` so we ensure they can be used
-        // for suggestions.
-        self.cm().visit_scopes(
-            ScopeSet::Macro(MacroKind::Derive),
-            &parent_scope,
-            ident.span.ctxt(),
-            |this, scope, _use_prelude, _ctxt| {
-                let Scope::Module(m, _) = scope else {
-                    return None;
-                };
-                for (_, resolution) in this.resolutions(m).borrow().iter() {
-                    let Some(binding) = resolution.borrow().best_binding() else {
-                        continue;
-                    };
-                    let Res::Def(DefKind::Macro(kinds), def_id) = binding.res() else {
-                        continue;
-                    };
-                    if !kinds.intersects(MacroKinds::ATTR | MacroKinds::DERIVE) {
-                        continue;
-                    }
-                    // By doing this all *imported* macros get added to the `macro_map` even if they
-                    // are *unused*, which makes the later suggestions find them and work.
-                    let _ = this.get_macro_by_def_id(def_id);
-                }
-                None::<()>
-            },
-        );
+        // Bring all unused `derive` macros into `macro_map` so we ensure they can be used for
+        // suggestions.
+        self.register_macros_for_all_crates();
 
         let is_expected =
             &|res: Res| res.macro_kinds().is_some_and(|k| k.contains(macro_kind.into()));

compiler/rustc_resolve/src/errors.rs

@@ -775,6 +775,17 @@ pub(crate) struct ConsiderAddingMacroExport {
     pub(crate) span: Span,
 }
 
+#[derive(Subdiagnostic)]
+#[suggestion(
+    resolve_consider_marking_as_pub_crate,
+    code = "pub(crate)",
+    applicability = "maybe-incorrect"
+)]
+pub(crate) struct ConsiderMarkingAsPubCrate {
+    #[primary_span]
+    pub(crate) vis_span: Span,
+}
+
 #[derive(Subdiagnostic)]
 #[note(resolve_consider_marking_as_pub)]
 pub(crate) struct ConsiderMarkingAsPub {

compiler/rustc_resolve/src/imports.rs

@@ -30,7 +30,7 @@ use crate::diagnostics::{DiagMode, Suggestion, import_candidates};
 use crate::errors::{
     CannotBeReexportedCratePublic, CannotBeReexportedCratePublicNS, CannotBeReexportedPrivate,
     CannotBeReexportedPrivateNS, CannotDetermineImportResolution, CannotGlobImportAllCrates,
-    ConsiderAddingMacroExport, ConsiderMarkingAsPub,
+    ConsiderAddingMacroExport, ConsiderMarkingAsPub, ConsiderMarkingAsPubCrate,
 };
 use crate::{
     AmbiguityError, AmbiguityKind, BindingKey, CmResolver, Determinacy, Finalize, ImportSuggestion,
@@ -184,6 +184,9 @@ pub(crate) struct ImportData<'ra> {
     /// |`use foo`        | `ModuleOrUniformRoot::CurrentScope`           | - |
     pub imported_module: Cell<Option<ModuleOrUniformRoot<'ra>>>,
     pub vis: Visibility,
+
+    /// Span of the visibility.
+    pub vis_span: Span,
 }
 
 /// All imports are unique and allocated on a same arena,
@@ -866,7 +869,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             }
             ImportKind::Glob { .. } => {
                 // FIXME: Use mutable resolver directly as a hack, this should be an output of
-                // specualtive resolution.
+                // speculative resolution.
                 self.get_mut_unchecked().resolve_glob_import(import);
                 return 0;
             }
@@ -903,7 +906,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         // We need the `target`, `source` can be extracted.
                         let imported_binding = this.import(binding, import);
                         // FIXME: Use mutable resolver directly as a hack, this should be an output of
-                        // specualtive resolution.
+                        // speculative resolution.
                         this.get_mut_unchecked().define_binding_local(
                             parent,
                             target,
@@ -917,7 +920,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                         if target.name != kw::Underscore {
                             let key = BindingKey::new(target, ns);
                             // FIXME: Use mutable resolver directly as a hack, this should be an output of
-                            // specualtive resolution.
+                            // speculative resolution.
                             this.get_mut_unchecked().update_local_resolution(
                                 parent,
                                 key,
@@ -1368,6 +1371,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             err.subdiagnostic( ConsiderAddingMacroExport {
                                 span: binding.span,
                             });
+                            err.subdiagnostic( ConsiderMarkingAsPubCrate {
+                                vis_span: import.vis_span,
+                            });
                         }
                         _ => {
                             err.subdiagnostic( ConsiderMarkingAsPub {

compiler/rustc_resolve/src/late.rs

@@ -4270,7 +4270,7 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         if path.len() == 2
                             && let [segment] = prefix_path
                         {
-                            // Delay to check whether methond name is an associated function or not
+                            // Delay to check whether method name is an associated function or not
                             // ```
                             // let foo = Foo {};
                             // foo::bar(); // possibly suggest to foo.bar();