Merging upstream version 1.73.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

24 files changed, 546 insertions, 338 deletions

diff --git a/compiler/rustc_mir_build/src/build/custom/parse.rs b/compiler/rustc_mir_build/src/build/custom/parse.rs
index 803207d9d..60c4a0416 100644
--- a/compiler/rustc_mir_build/src/build/custom/parse.rs
+++ b/compiler/rustc_mir_build/src/build/custom/parse.rs
@@ -74,7 +74,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
             kind @ StmtKind::Let { pattern, .. } => {
                 return Err(ParseError {
                     span: pattern.span,
-                    item_description: format!("{:?}", kind),
+                    item_description: format!("{kind:?}"),
                     expected: "expression".to_string(),
                 });
             }
@@ -241,9 +241,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
             });
         }
 
-        let Some(trailing) = block.expr else {
-            return Err(self.expr_error(expr_id, "terminator"))
-        };
+        let Some(trailing) = block.expr else { return Err(self.expr_error(expr_id, "terminator")) };
         let span = self.thir[trailing].span;
         let terminator = self.parse_terminator(trailing)?;
         data.terminator = Some(Terminator {
diff --git a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
index 4cb9d7bab..26662f5de 100644
--- a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
+++ b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
@@ -61,11 +61,9 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                 })
             },
             @call("mir_call", args) => {
-                let destination = self.parse_place(args[0])?;
-                let target = self.parse_block(args[1])?;
-                self.parse_call(args[2], destination, target)
+                self.parse_call(args)
             },
-            ExprKind::Match { scrutinee, arms } => {
+            ExprKind::Match { scrutinee, arms, .. } => {
                 let discr = self.parse_operand(*scrutinee)?;
                 self.parse_match(arms, expr.span).map(|t| TerminatorKind::SwitchInt { discr, targets: t })
             },
@@ -78,7 +76,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                 span,
                 item_description: "no arms".to_string(),
                 expected: "at least one arm".to_string(),
-            })
+            });
         };
 
         let otherwise = &self.thir[*otherwise];
@@ -87,7 +85,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                 span: otherwise.span,
                 item_description: format!("{:?}", otherwise.pattern.kind),
                 expected: "wildcard pattern".to_string(),
-            })
+            });
         };
         let otherwise = self.parse_block(otherwise.body)?;
 
@@ -100,7 +98,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                     span: arm.pattern.span,
                     item_description: format!("{:?}", arm.pattern.kind),
                     expected: "constant pattern".to_string(),
-                })
+                });
             };
             values.push(value.eval_bits(self.tcx, self.param_env, arm.pattern.ty));
             targets.push(self.parse_block(arm.body)?);
@@ -109,13 +107,14 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
         Ok(SwitchTargets::new(values.into_iter().zip(targets), otherwise))
     }
 
-    fn parse_call(
-        &self,
-        expr_id: ExprId,
-        destination: Place<'tcx>,
-        target: BasicBlock,
-    ) -> PResult<TerminatorKind<'tcx>> {
-        parse_by_kind!(self, expr_id, _, "function call",
+    fn parse_call(&self, args: &[ExprId]) -> PResult<TerminatorKind<'tcx>> {
+        let (destination, call) = parse_by_kind!(self, args[0], _, "function call",
+            ExprKind::Assign { lhs, rhs } => (*lhs, *rhs),
+        );
+        let destination = self.parse_place(destination)?;
+        let target = self.parse_block(args[1])?;
+
+        parse_by_kind!(self, call, _, "function call",
             ExprKind::Call { fun, args, from_hir_call, fn_span, .. } => {
                 let fun = self.parse_operand(*fun)?;
                 let args = args
@@ -192,12 +191,12 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                     fields.iter().map(|e| self.parse_operand(*e)).collect::<Result<_, _>>()?
                 ))
             },
-            ExprKind::Adt(box AdtExpr{ adt_def, variant_index, substs, fields, .. }) => {
+            ExprKind::Adt(box AdtExpr{ adt_def, variant_index, args, fields, .. }) => {
                 let is_union = adt_def.is_union();
                 let active_field_index = is_union.then(|| fields[0].name);
 
                 Ok(Rvalue::Aggregate(
-                    Box::new(AggregateKind::Adt(adt_def.did(), *variant_index, substs, None, active_field_index)),
+                    Box::new(AggregateKind::Adt(adt_def.did(), *variant_index, args, None, active_field_index)),
                     fields.iter().map(|f| self.parse_operand(f.expr)).collect::<Result<_, _>>()?
                 ))
             },
diff --git a/compiler/rustc_mir_build/src/build/expr/as_constant.rs b/compiler/rustc_mir_build/src/build/expr/as_constant.rs
index 3fe751ae0..aaa37446e 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_constant.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_constant.rs
@@ -75,10 +75,10 @@ pub fn as_constant_inner<'tcx>(
 
             Constant { span, user_ty, literal }
         }
-        ExprKind::NamedConst { def_id, substs, ref user_ty } => {
+        ExprKind::NamedConst { def_id, args, ref user_ty } => {
             let user_ty = user_ty.as_ref().and_then(push_cuta);
 
-            let uneval = mir::UnevaluatedConst::new(def_id, substs);
+            let uneval = mir::UnevaluatedConst::new(def_id, args);
             let literal = ConstantKind::Unevaluated(uneval, ty);
 
             Constant { user_ty, span, literal }
@@ -89,8 +89,8 @@ pub fn as_constant_inner<'tcx>(
 
             Constant { user_ty: None, span, literal }
         }
-        ExprKind::ConstBlock { did: def_id, substs } => {
-            let uneval = mir::UnevaluatedConst::new(def_id, substs);
+        ExprKind::ConstBlock { did: def_id, args } => {
+            let uneval = mir::UnevaluatedConst::new(def_id, args);
             let literal = ConstantKind::Unevaluated(uneval, ty);
 
             Constant { user_ty: None, span, literal }
diff --git a/compiler/rustc_mir_build/src/build/expr/as_place.rs b/compiler/rustc_mir_build/src/build/expr/as_place.rs
index 60acd279f..2e7ef265a 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_place.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_place.rs
@@ -175,11 +175,8 @@ fn to_upvars_resolved_place_builder<'tcx>(
     projection: &[PlaceElem<'tcx>],
 ) -> Option<PlaceBuilder<'tcx>> {
     let Some((capture_index, capture)) =
-        find_capture_matching_projections(
-            &cx.upvars,
-            var_hir_id,
-            &projection,
-        ) else {
+        find_capture_matching_projections(&cx.upvars, var_hir_id, &projection)
+    else {
         let closure_span = cx.tcx.def_span(closure_def_id);
         if !enable_precise_capture(closure_span) {
             bug!(
@@ -189,10 +186,7 @@ fn to_upvars_resolved_place_builder<'tcx>(
                 projection
             )
         } else {
-            debug!(
-                "No associated capture found for {:?}[{:#?}]",
-                var_hir_id, projection,
-            );
+            debug!("No associated capture found for {:?}[{:#?}]", var_hir_id, projection,);
         }
         return None;
     };
@@ -242,6 +236,9 @@ fn strip_prefix<'a, 'tcx>(
                 }
                 assert_matches!(iter.next(), Some(ProjectionElem::Field(..)));
             }
+            HirProjectionKind::OpaqueCast => {
+                assert_matches!(iter.next(), Some(ProjectionElem::OpaqueCast(..)));
+            }
             HirProjectionKind::Index | HirProjectionKind::Subslice => {
                 bug!("unexpected projection kind: {:?}", projection);
             }
@@ -736,5 +733,5 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
 /// Precise capture is enabled if user is using Rust Edition 2021 or higher.
 fn enable_precise_capture(closure_span: Span) -> bool {
-    closure_span.rust_2021()
+    closure_span.at_least_rust_2021()
 }
diff --git a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
index 32ffb990b..3220a184d 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
@@ -16,7 +16,7 @@ use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty::cast::{mir_cast_kind, CastTy};
 use rustc_middle::ty::layout::IntegerExt;
-use rustc_middle::ty::{self, Ty, UpvarSubsts};
+use rustc_middle::ty::{self, Ty, UpvarArgs};
 use rustc_span::Span;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
@@ -382,7 +382,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
             ExprKind::Closure(box ClosureExpr {
                 closure_id,
-                substs,
+                args,
                 ref upvars,
                 movability,
                 ref fake_reads,
@@ -470,19 +470,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     })
                     .collect();
 
-                let result = match substs {
-                    UpvarSubsts::Generator(substs) => {
+                let result = match args {
+                    UpvarArgs::Generator(args) => {
                         // We implicitly set the discriminant to 0. See
                         // librustc_mir/transform/deaggregator.rs for details.
                         let movability = movability.unwrap();
-                        Box::new(AggregateKind::Generator(
-                            closure_id.to_def_id(),
-                            substs,
-                            movability,
-                        ))
+                        Box::new(AggregateKind::Generator(closure_id.to_def_id(), args, movability))
                     }
-                    UpvarSubsts::Closure(substs) => {
-                        Box::new(AggregateKind::Closure(closure_id.to_def_id(), substs))
+                    UpvarArgs::Closure(args) => {
+                        Box::new(AggregateKind::Closure(closure_id.to_def_id(), args))
                     }
                 };
                 block.and(Rvalue::Aggregate(result, operands))
@@ -778,8 +774,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         // Not in a closure
                         debug_assert!(
                             local == ty::CAPTURE_STRUCT_LOCAL,
-                            "Expected local to be Local(1), found {:?}",
-                            local
+                            "Expected local to be Local(1), found {local:?}"
                         );
                         // Not in a closure
                         debug_assert!(
diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs
index e30fdcbbe..a5c86e31a 100644
--- a/compiler/rustc_mir_build/src/build/expr/into.rs
+++ b/compiler/rustc_mir_build/src/build/expr/into.rs
@@ -47,7 +47,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ExprKind::Block { block: ast_block } => {
                 this.ast_block(destination, block, ast_block, source_info)
             }
-            ExprKind::Match { scrutinee, ref arms } => {
+            ExprKind::Match { scrutinee, ref arms, .. } => {
                 this.match_expr(destination, expr_span, block, &this.thir[scrutinee], arms)
             }
             ExprKind::If { cond, then, else_opt, if_then_scope } => {
@@ -317,7 +317,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ExprKind::Adt(box AdtExpr {
                 adt_def,
                 variant_index,
-                substs,
+                args,
                 ref user_ty,
                 ref fields,
                 ref base,
@@ -382,7 +382,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let adt = Box::new(AggregateKind::Adt(
                     adt_def.did(),
                     variant_index,
-                    substs,
+                    args,
                     user_ty,
                     active_field_index,
                 ));
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index 10770213c..3c4507407 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -607,9 +607,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     // };
                     // ```
                     if let Some(place) = initializer.try_to_place(self) {
-                        let LocalInfo::User(BindingForm::Var(
-                            VarBindingForm { opt_match_place: Some((ref mut match_place, _)), .. },
-                        )) = **self.local_decls[local].local_info.as_mut().assert_crate_local() else {
+                        let LocalInfo::User(BindingForm::Var(VarBindingForm {
+                            opt_match_place: Some((ref mut match_place, _)),
+                            ..
+                        })) = **self.local_decls[local].local_info.as_mut().assert_crate_local()
+                        else {
                             bug!("Let binding to non-user variable.")
                         };
                         *match_place = Some(place);
@@ -804,7 +806,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            PatKind::Variant { adt_def, substs: _, variant_index, ref subpatterns } => {
+            PatKind::Variant { adt_def, args: _, variant_index, ref subpatterns } => {
                 for subpattern in subpatterns {
                     let subpattern_user_ty =
                         pattern_user_ty.clone().variant(adt_def, variant_index, subpattern.field);
@@ -1625,9 +1627,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // at least the first candidate ought to be tested
         assert!(
             total_candidate_count > candidates.len(),
-            "{}, {:#?}",
-            total_candidate_count,
-            candidates
+            "{total_candidate_count}, {candidates:#?}"
         );
         debug!("tested_candidates: {}", total_candidate_count - candidates.len());
         debug!("untested_candidates: {}", candidates.len());
@@ -2242,7 +2242,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         self.var_debug_info.push(VarDebugInfo {
             name,
             source_info: debug_source_info,
-            references: 0,
             value: VarDebugInfoContents::Place(for_arm_body.into()),
             argument_index: None,
         });
@@ -2262,7 +2261,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             self.var_debug_info.push(VarDebugInfo {
                 name,
                 source_info: debug_source_info,
-                references: 0,
                 value: VarDebugInfoContents::Place(ref_for_guard.into()),
                 argument_index: None,
             });
diff --git a/compiler/rustc_mir_build/src/build/matches/simplify.rs b/compiler/rustc_mir_build/src/build/matches/simplify.rs
index f6b1955fd..17ac1f4e0 100644
--- a/compiler/rustc_mir_build/src/build/matches/simplify.rs
+++ b/compiler/rustc_mir_build/src/build/matches/simplify.rs
@@ -259,13 +259,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            PatKind::Variant { adt_def, substs, variant_index, ref subpatterns } => {
+            PatKind::Variant { adt_def, args, variant_index, ref subpatterns } => {
                 let irrefutable = adt_def.variants().iter_enumerated().all(|(i, v)| {
                     i == variant_index || {
                         self.tcx.features().exhaustive_patterns
                             && !v
                                 .inhabited_predicate(self.tcx, adt_def)
-                                .subst(self.tcx, substs)
+                                .instantiate(self.tcx, args)
                                 .apply_ignore_module(self.tcx, self.param_env)
                     }
                 }) && (adt_def.did().is_local()
diff --git a/compiler/rustc_mir_build/src/build/matches/test.rs b/compiler/rustc_mir_build/src/build/matches/test.rs
index e6806177d..484e84909 100644
--- a/compiler/rustc_mir_build/src/build/matches/test.rs
+++ b/compiler/rustc_mir_build/src/build/matches/test.rs
@@ -30,7 +30,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// It is a bug to call this with a not-fully-simplified pattern.
     pub(super) fn test<'pat>(&mut self, match_pair: &MatchPair<'pat, 'tcx>) -> Test<'tcx> {
         match match_pair.pattern.kind {
-            PatKind::Variant { adt_def, substs: _, variant_index: _, subpatterns: _ } => Test {
+            PatKind::Variant { adt_def, args: _, variant_index: _, subpatterns: _ } => Test {
                 span: match_pair.pattern.span,
                 kind: TestKind::Switch {
                     adt_def,
@@ -88,7 +88,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         switch_ty: Ty<'tcx>,
         options: &mut FxIndexMap<ConstantKind<'tcx>, u128>,
     ) -> bool {
-        let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place) else {
+        let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place)
+        else {
             return false;
         };
 
@@ -126,7 +127,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         candidate: &Candidate<'pat, 'tcx>,
         variants: &mut BitSet<VariantIdx>,
     ) -> bool {
-        let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place) else {
+        let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place)
+        else {
             return false;
         };
 
@@ -173,16 +175,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             debug_assert_ne!(
                                 target_blocks[idx.index()],
                                 otherwise_block,
-                                "no candidates for tested discriminant: {:?}",
-                                discr,
+                                "no candidates for tested discriminant: {discr:?}",
                             );
                             Some((discr.val, target_blocks[idx.index()]))
                         } else {
                             debug_assert_eq!(
                                 target_blocks[idx.index()],
                                 otherwise_block,
-                                "found candidates for untested discriminant: {:?}",
-                                discr,
+                                "found candidates for untested discriminant: {discr:?}",
                             );
                             None
                         }
@@ -865,7 +865,7 @@ fn trait_method<'tcx>(
     tcx: TyCtxt<'tcx>,
     trait_def_id: DefId,
     method_name: Symbol,
-    substs: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
+    args: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
 ) -> ConstantKind<'tcx> {
     // The unhygienic comparison here is acceptable because this is only
     // used on known traits.
@@ -875,7 +875,7 @@ fn trait_method<'tcx>(
         .find(|item| item.kind == ty::AssocKind::Fn)
         .expect("trait method not found");
 
-    let method_ty = Ty::new_fn_def(tcx, item.def_id, substs);
+    let method_ty = Ty::new_fn_def(tcx, item.def_id, args);
 
     ConstantKind::zero_sized(method_ty)
 }
diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index d828e71c7..2a23a69b5 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -10,6 +10,7 @@ use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::{GeneratorKind, Node};
+use rustc_index::bit_set::GrowableBitSet;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
@@ -93,8 +94,7 @@ fn mir_build(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
             || body.basic_blocks.has_free_regions()
             || body.var_debug_info.has_free_regions()
             || body.yield_ty().has_free_regions()),
-        "Unexpected free regions in MIR: {:?}",
-        body,
+        "Unexpected free regions in MIR: {body:?}",
     );
 
     body
@@ -215,6 +215,14 @@ struct Builder<'a, 'tcx> {
     unit_temp: Option<Place<'tcx>>,
 
     var_debug_info: Vec<VarDebugInfo<'tcx>>,
+
+    // A cache for `maybe_lint_level_roots_bounded`. That function is called
+    // repeatedly, and each time it effectively traces a path through a tree
+    // structure from a node towards the root, doing an attribute check on each
+    // node along the way. This cache records which nodes trace all the way to
+    // the root (most of them do) and saves us from retracing many sub-paths
+    // many times, and rechecking many nodes.
+    lint_level_roots_cache: GrowableBitSet<hir::ItemLocalId>,
 }
 
 type CaptureMap<'tcx> = SortedIndexMultiMap<usize, hir::HirId, Capture<'tcx>>;
@@ -473,7 +481,7 @@ fn construct_fn<'tcx>(
     let (yield_ty, return_ty) = if generator_kind.is_some() {
         let gen_ty = arguments[thir::UPVAR_ENV_PARAM].ty;
         let gen_sig = match gen_ty.kind() {
-            ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
+            ty::Generator(_, gen_args, ..) => gen_args.as_generator().sig(),
             _ => {
                 span_bug!(span, "generator w/o generator type: {:?}", gen_ty)
             }
@@ -562,7 +570,7 @@ fn construct_const<'a, 'tcx>(
     // Figure out what primary body this item has.
     let (span, const_ty_span) = match tcx.hir().get(hir_id) {
         Node::Item(hir::Item {
-            kind: hir::ItemKind::Static(ty, _, _) | hir::ItemKind::Const(ty, _),
+            kind: hir::ItemKind::Static(ty, _, _) | hir::ItemKind::Const(ty, _, _),
             span,
             ..
         })
@@ -618,11 +626,9 @@ fn construct_error(tcx: TyCtxt<'_>, def: LocalDefId, err: ErrorGuaranteed) -> Bo
     let num_params = match body_owner_kind {
         hir::BodyOwnerKind::Fn => tcx.fn_sig(def).skip_binder().inputs().skip_binder().len(),
         hir::BodyOwnerKind::Closure => {
-            let ty = tcx.type_of(def).subst_identity();
+            let ty = tcx.type_of(def).instantiate_identity();
             match ty.kind() {
-                ty::Closure(_, substs) => {
-                    1 + substs.as_closure().sig().inputs().skip_binder().len()
-                }
+                ty::Closure(_, args) => 1 + args.as_closure().sig().inputs().skip_binder().len(),
                 ty::Generator(..) => 2,
                 _ => bug!("expected closure or generator, found {ty:?}"),
             }
@@ -725,6 +731,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             var_indices: Default::default(),
             unit_temp: None,
             var_debug_info: vec![],
+            lint_level_roots_cache: GrowableBitSet::new_empty(),
         };
 
         assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
@@ -768,9 +775,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             closure_ty = *ty;
         }
 
-        let upvar_substs = match closure_ty.kind() {
-            ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
-            ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
+        let upvar_args = match closure_ty.kind() {
+            ty::Closure(_, args) => ty::UpvarArgs::Closure(args),
+            ty::Generator(_, args, _) => ty::UpvarArgs::Generator(args),
             _ => return,
         };
 
@@ -779,7 +786,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // with the closure's DefId. Here, we run through that vec of UpvarIds for
         // the given closure and use the necessary information to create upvar
         // debuginfo and to fill `self.upvars`.
-        let capture_tys = upvar_substs.upvar_tys();
+        let capture_tys = upvar_args.upvar_tys();
 
         let tcx = self.tcx;
         self.upvars = tcx
@@ -813,7 +820,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 };
                 self.var_debug_info.push(VarDebugInfo {
                     name,
-                    references: 0,
                     source_info: SourceInfo::outermost(captured_place.var_ident.span),
                     value: VarDebugInfoContents::Place(use_place),
                     argument_index: None,
@@ -844,7 +850,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 self.var_debug_info.push(VarDebugInfo {
                     name,
                     source_info,
-                    references: 0,
                     value: VarDebugInfoContents::Place(arg_local.into()),
                     argument_index: Some(argument_index as u16 + 1),
                 });
@@ -969,9 +974,9 @@ pub(crate) fn parse_float_into_scalar(
     match float_ty {
         ty::FloatTy::F32 => {
             let Ok(rust_f) = num.parse::<f32>() else { return None };
-            let mut f = num.parse::<Single>().unwrap_or_else(|e| {
-                panic!("apfloat::ieee::Single failed to parse `{}`: {:?}", num, e)
-            });
+            let mut f = num
+                .parse::<Single>()
+                .unwrap_or_else(|e| panic!("apfloat::ieee::Single failed to parse `{num}`: {e:?}"));
 
             assert!(
                 u128::from(rust_f.to_bits()) == f.to_bits(),
@@ -992,9 +997,9 @@ pub(crate) fn parse_float_into_scalar(
         }
         ty::FloatTy::F64 => {
             let Ok(rust_f) = num.parse::<f64>() else { return None };
-            let mut f = num.parse::<Double>().unwrap_or_else(|e| {
-                panic!("apfloat::ieee::Double failed to parse `{}`: {:?}", num, e)
-            });
+            let mut f = num
+                .parse::<Double>()
+                .unwrap_or_else(|e| panic!("apfloat::ieee::Double failed to parse `{num}`: {e:?}"));
 
             assert!(
                 u128::from(rust_f.to_bits()) == f.to_bits(),
diff --git a/compiler/rustc_mir_build/src/build/scope.rs b/compiler/rustc_mir_build/src/build/scope.rs
index 72374102c..a96288a11 100644
--- a/compiler/rustc_mir_build/src/build/scope.rs
+++ b/compiler/rustc_mir_build/src/build/scope.rs
@@ -90,8 +90,8 @@ use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::middle::region;
 use rustc_middle::mir::*;
 use rustc_middle::thir::{Expr, LintLevel};
-
 use rustc_middle::ty::Ty;
+use rustc_session::lint::Level;
 use rustc_span::{Span, DUMMY_SP};
 
 #[derive(Debug)]
@@ -760,20 +760,25 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     ) {
         let (current_root, parent_root) =
             if self.tcx.sess.opts.unstable_opts.maximal_hir_to_mir_coverage {
-                // Some consumers of rustc need to map MIR locations back to HIR nodes. Currently the
-                // the only part of rustc that tracks MIR -> HIR is the `SourceScopeLocalData::lint_root`
-                // field that tracks lint levels for MIR locations. Normally the number of source scopes
-                // is limited to the set of nodes with lint annotations. The -Zmaximal-hir-to-mir-coverage
-                // flag changes this behavior to maximize the number of source scopes, increasing the
-                // granularity of the MIR->HIR mapping.
+                // Some consumers of rustc need to map MIR locations back to HIR nodes. Currently
+                // the the only part of rustc that tracks MIR -> HIR is the
+                // `SourceScopeLocalData::lint_root` field that tracks lint levels for MIR
+                // locations. Normally the number of source scopes is limited to the set of nodes
+                // with lint annotations. The -Zmaximal-hir-to-mir-coverage flag changes this
+                // behavior to maximize the number of source scopes, increasing the granularity of
+                // the MIR->HIR mapping.
                 (current_id, parent_id)
             } else {
-                // Use `maybe_lint_level_root_bounded` with `self.hir_id` as a bound
-                // to avoid adding Hir dependencies on our parents.
-                // We estimate the true lint roots here to avoid creating a lot of source scopes.
+                // Use `maybe_lint_level_root_bounded` to avoid adding Hir dependencies on our
+                // parents. We estimate the true lint roots here to avoid creating a lot of source
+                // scopes.
                 (
-                    self.tcx.maybe_lint_level_root_bounded(current_id, self.hir_id),
-                    self.tcx.maybe_lint_level_root_bounded(parent_id, self.hir_id),
+                    self.maybe_lint_level_root_bounded(current_id),
+                    if parent_id == self.hir_id {
+                        parent_id // this is very common
+                    } else {
+                        self.maybe_lint_level_root_bounded(parent_id)
+                    },
                 )
             };
 
@@ -783,6 +788,50 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         }
     }
 
+    /// Walks upwards from `orig_id` to find a node which might change lint levels with attributes.
+    /// It stops at `self.hir_id` and just returns it if reached.
+    fn maybe_lint_level_root_bounded(&mut self, orig_id: HirId) -> HirId {
+        // This assertion lets us just store `ItemLocalId` in the cache, rather
+        // than the full `HirId`.
+        assert_eq!(orig_id.owner, self.hir_id.owner);
+
+        let mut id = orig_id;
+        let hir = self.tcx.hir();
+        loop {
+            if id == self.hir_id {
+                // This is a moderately common case, mostly hit for previously unseen nodes.
+                break;
+            }
+
+            if hir.attrs(id).iter().any(|attr| Level::from_attr(attr).is_some()) {
+                // This is a rare case. It's for a node path that doesn't reach the root due to an
+                // intervening lint level attribute. This result doesn't get cached.
+                return id;
+            }
+
+            let next = hir.parent_id(id);
+            if next == id {
+                bug!("lint traversal reached the root of the crate");
+            }
+            id = next;
+
+            // This lookup is just an optimization; it can be removed without affecting
+            // functionality. It might seem strange to see this at the end of this loop, but the
+            // `orig_id` passed in to this function is almost always previously unseen, for which a
+            // lookup will be a miss. So we only do lookups for nodes up the parent chain, where
+            // cache lookups have a very high hit rate.
+            if self.lint_level_roots_cache.contains(id.local_id) {
+                break;
+            }
+        }
+
+        // `orig_id` traced to `self_id`; record this fact. If `orig_id` is a leaf node it will
+        // rarely (never?) subsequently be searched for, but it's hard to know if that is the case.
+        // The performance wins from the cache all come from caching non-leaf nodes.
+        self.lint_level_roots_cache.insert(orig_id.local_id);
+        self.hir_id
+    }
+
     /// Creates a new source scope, nested in the current one.
     pub(crate) fn new_source_scope(
         &mut self,
diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs
index 6b2b140fa..192bd4a83 100644
--- a/compiler/rustc_mir_build/src/check_unsafety.rs
+++ b/compiler/rustc_mir_build/src/check_unsafety.rs
@@ -91,7 +91,12 @@ impl<'tcx> UnsafetyVisitor<'_, 'tcx> {
                 kind.emit_unsafe_op_in_unsafe_fn_lint(self.tcx, self.hir_context, span);
             }
             SafetyContext::Safe => {
-                kind.emit_requires_unsafe_err(self.tcx, span, unsafe_op_in_unsafe_fn_allowed);
+                kind.emit_requires_unsafe_err(
+                    self.tcx,
+                    span,
+                    self.hir_context,
+                    unsafe_op_in_unsafe_fn_allowed,
+                );
             }
         }
     }
@@ -383,7 +388,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             ExprKind::Adt(box AdtExpr {
                 adt_def,
                 variant_index: _,
-                substs: _,
+                args: _,
                 user_ty: _,
                 fields: _,
                 base: _,
@@ -393,14 +398,14 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             },
             ExprKind::Closure(box ClosureExpr {
                 closure_id,
-                substs: _,
+                args: _,
                 upvars: _,
                 movability: _,
                 fake_reads: _,
             }) => {
                 self.visit_inner_body(closure_id);
             }
-            ExprKind::ConstBlock { did, substs: _ } => {
+            ExprKind::ConstBlock { did, args: _ } => {
                 let def_id = did.expect_local();
                 self.visit_inner_body(def_id);
             }
@@ -602,98 +607,164 @@ impl UnsafeOpKind {
         &self,
         tcx: TyCtxt<'_>,
         span: Span,
+        hir_context: hir::HirId,
         unsafe_op_in_unsafe_fn_allowed: bool,
     ) {
+        let note_non_inherited = tcx.hir().parent_iter(hir_context).find(|(id, node)| {
+            if let hir::Node::Expr(block) = node
+                && let hir::ExprKind::Block(block, _) = block.kind
+                && let hir::BlockCheckMode::UnsafeBlock(_) = block.rules
+            {
+                true
+            }
+            else if let Some(sig) = tcx.hir().fn_sig_by_hir_id(*id)
+                && sig.header.is_unsafe()
+            {
+                true
+            } else {
+                false
+            }
+        });
+        let unsafe_not_inherited_note = if let Some((id, _)) = note_non_inherited {
+            let span = tcx.hir().span(id);
+            let span = tcx.sess.source_map().guess_head_span(span);
+            Some(UnsafeNotInheritedNote { span })
+        } else {
+            None
+        };
+
         match self {
             CallToUnsafeFunction(Some(did)) if unsafe_op_in_unsafe_fn_allowed => {
                 tcx.sess.emit_err(CallToUnsafeFunctionRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
                     span,
+                    unsafe_not_inherited_note,
                     function: &tcx.def_path_str(*did),
                 });
             }
             CallToUnsafeFunction(Some(did)) => {
                 tcx.sess.emit_err(CallToUnsafeFunctionRequiresUnsafe {
                     span,
+                    unsafe_not_inherited_note,
                     function: &tcx.def_path_str(*did),
                 });
             }
             CallToUnsafeFunction(None) if unsafe_op_in_unsafe_fn_allowed => {
                 tcx.sess.emit_err(
-                    CallToUnsafeFunctionRequiresUnsafeNamelessUnsafeOpInUnsafeFnAllowed { span },
+                    CallToUnsafeFunctionRequiresUnsafeNamelessUnsafeOpInUnsafeFnAllowed {
+                        span,
+                        unsafe_not_inherited_note,
+                    },
                 );
             }
             CallToUnsafeFunction(None) => {
-                tcx.sess.emit_err(CallToUnsafeFunctionRequiresUnsafeNameless { span });
+                tcx.sess.emit_err(CallToUnsafeFunctionRequiresUnsafeNameless {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             UseOfInlineAssembly if unsafe_op_in_unsafe_fn_allowed => {
-                tcx.sess
-                    .emit_err(UseOfInlineAssemblyRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span });
+                tcx.sess.emit_err(UseOfInlineAssemblyRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             UseOfInlineAssembly => {
-                tcx.sess.emit_err(UseOfInlineAssemblyRequiresUnsafe { span });
+                tcx.sess.emit_err(UseOfInlineAssemblyRequiresUnsafe {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             InitializingTypeWith if unsafe_op_in_unsafe_fn_allowed => {
-                tcx.sess
-                    .emit_err(InitializingTypeWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span });
+                tcx.sess.emit_err(InitializingTypeWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             InitializingTypeWith => {
-                tcx.sess.emit_err(InitializingTypeWithRequiresUnsafe { span });
+                tcx.sess.emit_err(InitializingTypeWithRequiresUnsafe {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             UseOfMutableStatic if unsafe_op_in_unsafe_fn_allowed => {
-                tcx.sess
-                    .emit_err(UseOfMutableStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span });
+                tcx.sess.emit_err(UseOfMutableStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             UseOfMutableStatic => {
-                tcx.sess.emit_err(UseOfMutableStaticRequiresUnsafe { span });
+                tcx.sess
+                    .emit_err(UseOfMutableStaticRequiresUnsafe { span, unsafe_not_inherited_note });
             }
             UseOfExternStatic if unsafe_op_in_unsafe_fn_allowed => {
-                tcx.sess
-                    .emit_err(UseOfExternStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span });
+                tcx.sess.emit_err(UseOfExternStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             UseOfExternStatic => {
-                tcx.sess.emit_err(UseOfExternStaticRequiresUnsafe { span });
+                tcx.sess
+                    .emit_err(UseOfExternStaticRequiresUnsafe { span, unsafe_not_inherited_note });
             }
             DerefOfRawPointer if unsafe_op_in_unsafe_fn_allowed => {
-                tcx.sess
-                    .emit_err(DerefOfRawPointerRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span });
+                tcx.sess.emit_err(DerefOfRawPointerRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             DerefOfRawPointer => {
-                tcx.sess.emit_err(DerefOfRawPointerRequiresUnsafe { span });
+                tcx.sess
+                    .emit_err(DerefOfRawPointerRequiresUnsafe { span, unsafe_not_inherited_note });
             }
             AccessToUnionField if unsafe_op_in_unsafe_fn_allowed => {
-                tcx.sess
-                    .emit_err(AccessToUnionFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span });
+                tcx.sess.emit_err(AccessToUnionFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             AccessToUnionField => {
-                tcx.sess.emit_err(AccessToUnionFieldRequiresUnsafe { span });
+                tcx.sess
+                    .emit_err(AccessToUnionFieldRequiresUnsafe { span, unsafe_not_inherited_note });
             }
             MutationOfLayoutConstrainedField if unsafe_op_in_unsafe_fn_allowed => {
                 tcx.sess.emit_err(
                     MutationOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
                         span,
+                        unsafe_not_inherited_note,
                     },
                 );
             }
             MutationOfLayoutConstrainedField => {
-                tcx.sess.emit_err(MutationOfLayoutConstrainedFieldRequiresUnsafe { span });
+                tcx.sess.emit_err(MutationOfLayoutConstrainedFieldRequiresUnsafe {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             BorrowOfLayoutConstrainedField if unsafe_op_in_unsafe_fn_allowed => {
                 tcx.sess.emit_err(
-                    BorrowOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed { span },
+                    BorrowOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+                        span,
+                        unsafe_not_inherited_note,
+                    },
                 );
             }
             BorrowOfLayoutConstrainedField => {
-                tcx.sess.emit_err(BorrowOfLayoutConstrainedFieldRequiresUnsafe { span });
+                tcx.sess.emit_err(BorrowOfLayoutConstrainedFieldRequiresUnsafe {
+                    span,
+                    unsafe_not_inherited_note,
+                });
             }
             CallToFunctionWith(did) if unsafe_op_in_unsafe_fn_allowed => {
                 tcx.sess.emit_err(CallToFunctionWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
                     span,
+                    unsafe_not_inherited_note,
                     function: &tcx.def_path_str(*did),
                 });
             }
             CallToFunctionWith(did) => {
                 tcx.sess.emit_err(CallToFunctionWithRequiresUnsafe {
                     span,
+                    unsafe_not_inherited_note,
                     function: &tcx.def_path_str(*did),
                 });
             }
@@ -712,9 +783,7 @@ pub fn thir_check_unsafety(tcx: TyCtxt<'_>, def: LocalDefId) {
         return;
     }
 
-    let Ok((thir, expr)) = tcx.thir_body(def) else {
-        return
-    };
+    let Ok((thir, expr)) = tcx.thir_body(def) else { return };
     let thir = &thir.borrow();
     // If `thir` is empty, a type error occurred, skip this body.
     if thir.exprs.is_empty() {
diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs
index df00cc75c..3ff3387a7 100644
--- a/compiler/rustc_mir_build/src/errors.rs
+++ b/compiler/rustc_mir_build/src/errors.rs
@@ -119,6 +119,8 @@ pub struct CallToUnsafeFunctionRequiresUnsafe<'a> {
     #[label]
     pub span: Span,
     pub function: &'a str,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -128,6 +130,8 @@ pub struct CallToUnsafeFunctionRequiresUnsafeNameless {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -138,6 +142,8 @@ pub struct CallToUnsafeFunctionRequiresUnsafeUnsafeOpInUnsafeFnAllowed<'a> {
     #[label]
     pub span: Span,
     pub function: &'a str,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -150,6 +156,8 @@ pub struct CallToUnsafeFunctionRequiresUnsafeNamelessUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -159,6 +167,8 @@ pub struct UseOfInlineAssemblyRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -168,6 +178,8 @@ pub struct UseOfInlineAssemblyRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -177,6 +189,8 @@ pub struct InitializingTypeWithRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -189,6 +203,8 @@ pub struct InitializingTypeWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -198,6 +214,8 @@ pub struct UseOfMutableStaticRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -207,6 +225,8 @@ pub struct UseOfMutableStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -216,6 +236,8 @@ pub struct UseOfExternStaticRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -225,6 +247,8 @@ pub struct UseOfExternStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -234,6 +258,8 @@ pub struct DerefOfRawPointerRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -243,6 +269,8 @@ pub struct DerefOfRawPointerRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -252,6 +280,8 @@ pub struct AccessToUnionFieldRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -261,6 +291,8 @@ pub struct AccessToUnionFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -270,6 +302,8 @@ pub struct MutationOfLayoutConstrainedFieldRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -282,6 +316,8 @@ pub struct MutationOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllow
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -291,6 +327,8 @@ pub struct BorrowOfLayoutConstrainedFieldRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -303,6 +341,8 @@ pub struct BorrowOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed
     #[primary_span]
     #[label]
     pub span: Span,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -313,6 +353,8 @@ pub struct CallToFunctionWithRequiresUnsafe<'a> {
     #[label]
     pub span: Span,
     pub function: &'a str,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
 
 #[derive(Diagnostic)]
@@ -323,6 +365,15 @@ pub struct CallToFunctionWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed<'a> {
     #[label]
     pub span: Span,
     pub function: &'a str,
+    #[subdiagnostic]
+    pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
+}
+
+#[derive(Subdiagnostic)]
+#[label(mir_build_unsafe_not_inherited)]
+pub struct UnsafeNotInheritedNote {
+    #[primary_span]
+    pub span: Span,
 }
 
 #[derive(LintDiagnostic)]
@@ -403,17 +454,13 @@ impl<'a> IntoDiagnostic<'a> for NonExhaustivePatternsTypeNotEmpty<'_, '_, '_> {
         if self.span.eq_ctxt(self.expr_span) {
             // Get the span for the empty match body `{}`.
             let (indentation, more) = if let Some(snippet) = sm.indentation_before(self.span) {
-                (format!("\n{}", snippet), "    ")
+                (format!("\n{snippet}"), "    ")
             } else {
                 (" ".to_string(), "")
             };
             suggestion = Some((
                 self.span.shrink_to_hi().with_hi(self.expr_span.hi()),
-                format!(
-                    " {{{indentation}{more}_ => todo!(),{indentation}}}",
-                    indentation = indentation,
-                    more = more,
-                ),
+                format!(" {{{indentation}{more}_ => todo!(),{indentation}}}",),
             ));
         }
 
diff --git a/compiler/rustc_mir_build/src/lib.rs b/compiler/rustc_mir_build/src/lib.rs
index 4fdc3178c..099fefbf0 100644
--- a/compiler/rustc_mir_build/src/lib.rs
+++ b/compiler/rustc_mir_build/src/lib.rs
@@ -19,7 +19,7 @@ extern crate rustc_middle;
 mod build;
 mod check_unsafety;
 mod errors;
-mod lints;
+pub mod lints;
 pub mod thir;
 
 use rustc_middle::query::Providers;
diff --git a/compiler/rustc_mir_build/src/lints.rs b/compiler/rustc_mir_build/src/lints.rs
index 8e41957af..7fb73b5c7 100644
--- a/compiler/rustc_mir_build/src/lints.rs
+++ b/compiler/rustc_mir_build/src/lints.rs
@@ -3,27 +3,43 @@ use rustc_data_structures::graph::iterate::{
     NodeStatus, TriColorDepthFirstSearch, TriColorVisitor,
 };
 use rustc_hir::def::DefKind;
-use rustc_middle::mir::{self, BasicBlock, BasicBlocks, Body, Operand, TerminatorKind};
-use rustc_middle::ty::subst::{GenericArg, InternalSubsts};
-use rustc_middle::ty::{self, Instance, TyCtxt};
+use rustc_middle::mir::{self, BasicBlock, BasicBlocks, Body, Terminator, TerminatorKind};
+use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
+use rustc_middle::ty::{GenericArg, GenericArgs};
 use rustc_session::lint::builtin::UNCONDITIONAL_RECURSION;
 use rustc_span::Span;
 use std::ops::ControlFlow;
 
 pub(crate) fn check<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
+    check_call_recursion(tcx, body);
+}
+
+fn check_call_recursion<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
     let def_id = body.source.def_id().expect_local();
 
     if let DefKind::Fn | DefKind::AssocFn = tcx.def_kind(def_id) {
-        // If this is trait/impl method, extract the trait's substs.
-        let trait_substs = match tcx.trait_of_item(def_id.to_def_id()) {
+        // If this is trait/impl method, extract the trait's args.
+        let trait_args = match tcx.trait_of_item(def_id.to_def_id()) {
             Some(trait_def_id) => {
-                let trait_substs_count = tcx.generics_of(trait_def_id).count();
-                &InternalSubsts::identity_for_item(tcx, def_id)[..trait_substs_count]
+                let trait_args_count = tcx.generics_of(trait_def_id).count();
+                &GenericArgs::identity_for_item(tcx, def_id)[..trait_args_count]
             }
             _ => &[],
         };
 
-        let mut vis = Search { tcx, body, reachable_recursive_calls: vec![], trait_substs };
+        check_recursion(tcx, body, CallRecursion { trait_args })
+    }
+}
+
+fn check_recursion<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    body: &Body<'tcx>,
+    classifier: impl TerminatorClassifier<'tcx>,
+) {
+    let def_id = body.source.def_id().expect_local();
+
+    if let DefKind::Fn | DefKind::AssocFn = tcx.def_kind(def_id) {
+        let mut vis = Search { tcx, body, classifier, reachable_recursive_calls: vec![] };
         if let Some(NonRecursive) =
             TriColorDepthFirstSearch::new(&body.basic_blocks).run_from_start(&mut vis)
         {
@@ -46,20 +62,66 @@ pub(crate) fn check<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
     }
 }
 
+/// Requires drop elaboration to have been performed first.
+pub fn check_drop_recursion<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
+    let def_id = body.source.def_id().expect_local();
+
+    // First check if `body` is an `fn drop()` of `Drop`
+    if let DefKind::AssocFn = tcx.def_kind(def_id) &&
+        let Some(trait_ref) = tcx.impl_of_method(def_id.to_def_id()).and_then(|def_id| tcx.impl_trait_ref(def_id)) &&
+        let Some(drop_trait) = tcx.lang_items().drop_trait() && drop_trait == trait_ref.instantiate_identity().def_id {
+
+        // It was. Now figure out for what type `Drop` is implemented and then
+        // check for recursion.
+        if let ty::Ref(_, dropped_ty, _) = tcx.liberate_late_bound_regions(
+            def_id.to_def_id(),
+            tcx.fn_sig(def_id).instantiate_identity().input(0),
+        ).kind() {
+            check_recursion(tcx, body, RecursiveDrop { drop_for: *dropped_ty });
+        }
+    }
+}
+
+trait TerminatorClassifier<'tcx> {
+    fn is_recursive_terminator(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        body: &Body<'tcx>,
+        terminator: &Terminator<'tcx>,
+    ) -> bool;
+}
+
 struct NonRecursive;
 
-struct Search<'mir, 'tcx> {
+struct Search<'mir, 'tcx, C: TerminatorClassifier<'tcx>> {
     tcx: TyCtxt<'tcx>,
     body: &'mir Body<'tcx>,
-    trait_substs: &'tcx [GenericArg<'tcx>],
+    classifier: C,
 
     reachable_recursive_calls: Vec<Span>,
 }
 
-impl<'mir, 'tcx> Search<'mir, 'tcx> {
+struct CallRecursion<'tcx> {
+    trait_args: &'tcx [GenericArg<'tcx>],
+}
+
+struct RecursiveDrop<'tcx> {
+    /// The type that `Drop` is implemented for.
+    drop_for: Ty<'tcx>,
+}
+
+impl<'tcx> TerminatorClassifier<'tcx> for CallRecursion<'tcx> {
     /// Returns `true` if `func` refers to the function we are searching in.
-    fn is_recursive_call(&self, func: &Operand<'tcx>, args: &[Operand<'tcx>]) -> bool {
-        let Search { tcx, body, trait_substs, .. } = *self;
+    fn is_recursive_terminator(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        body: &Body<'tcx>,
+        terminator: &Terminator<'tcx>,
+    ) -> bool {
+        let TerminatorKind::Call { func, args, .. } = &terminator.kind else {
+            return false;
+        };
+
         // Resolving function type to a specific instance that is being called is expensive. To
         // avoid the cost we check the number of arguments first, which is sufficient to reject
         // most of calls as non-recursive.
@@ -70,30 +132,46 @@ impl<'mir, 'tcx> Search<'mir, 'tcx> {
         let param_env = tcx.param_env(caller);
 
         let func_ty = func.ty(body, tcx);
-        if let ty::FnDef(callee, substs) = *func_ty.kind() {
-            let normalized_substs = tcx.normalize_erasing_regions(param_env, substs);
-            let (callee, call_substs) = if let Ok(Some(instance)) =
-                Instance::resolve(tcx, param_env, callee, normalized_substs)
+        if let ty::FnDef(callee, args) = *func_ty.kind() {
+            let normalized_args = tcx.normalize_erasing_regions(param_env, args);
+            let (callee, call_args) = if let Ok(Some(instance)) =
+                Instance::resolve(tcx, param_env, callee, normalized_args)
             {
-                (instance.def_id(), instance.substs)
+                (instance.def_id(), instance.args)
             } else {
-                (callee, normalized_substs)
+                (callee, normalized_args)
             };
 
             // FIXME(#57965): Make this work across function boundaries
 
-            // If this is a trait fn, the substs on the trait have to match, or we might be
+            // If this is a trait fn, the args on the trait have to match, or we might be
             // calling into an entirely different method (for example, a call from the default
             // method in the trait to `<A as Trait<B>>::method`, where `A` and/or `B` are
             // specific types).
-            return callee == caller && &call_substs[..trait_substs.len()] == trait_substs;
+            return callee == caller && &call_args[..self.trait_args.len()] == self.trait_args;
         }
 
         false
     }
 }
 
-impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
+impl<'tcx> TerminatorClassifier<'tcx> for RecursiveDrop<'tcx> {
+    fn is_recursive_terminator(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        body: &Body<'tcx>,
+        terminator: &Terminator<'tcx>,
+    ) -> bool {
+        let TerminatorKind::Drop { place, .. } = &terminator.kind else { return false };
+
+        let dropped_ty = place.ty(body, tcx).ty;
+        dropped_ty == self.drop_for
+    }
+}
+
+impl<'mir, 'tcx, C: TerminatorClassifier<'tcx>> TriColorVisitor<BasicBlocks<'tcx>>
+    for Search<'mir, 'tcx, C>
+{
     type BreakVal = NonRecursive;
 
     fn node_examined(
@@ -138,10 +216,8 @@ impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
     fn node_settled(&mut self, bb: BasicBlock) -> ControlFlow<Self::BreakVal> {
         // When we examine a node for the last time, remember it if it is a recursive call.
         let terminator = self.body[bb].terminator();
-        if let TerminatorKind::Call { func, args, .. } = &terminator.kind {
-            if self.is_recursive_call(func, args) {
-                self.reachable_recursive_calls.push(terminator.source_info.span);
-            }
+        if self.classifier.is_recursive_terminator(self.tcx, self.body, terminator) {
+            self.reachable_recursive_calls.push(terminator.source_info.span);
         }
 
         ControlFlow::Continue(())
@@ -149,15 +225,14 @@ impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
 
     fn ignore_edge(&mut self, bb: BasicBlock, target: BasicBlock) -> bool {
         let terminator = self.body[bb].terminator();
-        if terminator.unwind() == Some(&mir::UnwindAction::Cleanup(target))
-            && terminator.successors().count() > 1
+        let ignore_unwind = terminator.unwind() == Some(&mir::UnwindAction::Cleanup(target))
+            && terminator.successors().count() > 1;
+        if ignore_unwind || self.classifier.is_recursive_terminator(self.tcx, self.body, terminator)
         {
             return true;
         }
-        // Don't traverse successors of recursive calls or false CFG edges.
-        match self.body[bb].terminator().kind {
-            TerminatorKind::Call { ref func, ref args, .. } => self.is_recursive_call(func, args),
-            TerminatorKind::FalseEdge { imaginary_target, .. } => imaginary_target == target,
+        match &terminator.kind {
+            TerminatorKind::FalseEdge { imaginary_target, .. } => imaginary_target == &target,
             _ => false,
         }
     }
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index 37537683f..6c1f7d7a6 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -15,9 +15,9 @@ use rustc_middle::thir::*;
 use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AutoBorrow, AutoBorrowMutability, PointerCoercion,
 };
-use rustc_middle::ty::subst::InternalSubsts;
+use rustc_middle::ty::GenericArgs;
 use rustc_middle::ty::{
-    self, AdtKind, InlineConstSubsts, InlineConstSubstsParts, ScalarInt, Ty, UpvarSubsts, UserType,
+    self, AdtKind, InlineConstArgs, InlineConstArgsParts, ScalarInt, Ty, UpvarArgs, UserType,
 };
 use rustc_span::{sym, Span};
 use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
@@ -41,11 +41,6 @@ impl<'tcx> Cx<'tcx> {
 
         let mut expr = self.make_mirror_unadjusted(hir_expr);
 
-        let adjustment_span = match self.adjustment_span {
-            Some((hir_id, span)) if hir_id == hir_expr.hir_id => Some(span),
-            _ => None,
-        };
-
         trace!(?expr.ty);
 
         // Now apply adjustments, if any.
@@ -53,12 +48,7 @@ impl<'tcx> Cx<'tcx> {
             for adjustment in self.typeck_results.expr_adjustments(hir_expr) {
                 trace!(?expr, ?adjustment);
                 let span = expr.span;
-                expr = self.apply_adjustment(
-                    hir_expr,
-                    expr,
-                    adjustment,
-                    adjustment_span.unwrap_or(span),
-                );
+                expr = self.apply_adjustment(hir_expr, expr, adjustment, span);
             }
         }
 
@@ -220,7 +210,7 @@ impl<'tcx> Cx<'tcx> {
 
             let res = self.typeck_results().qpath_res(qpath, source.hir_id);
             let ty = self.typeck_results().node_type(source.hir_id);
-            let ty::Adt(adt_def, substs) = ty.kind() else {
+            let ty::Adt(adt_def, args) = ty.kind() else {
                 return ExprKind::Cast { source: self.mirror_expr(source) };
             };
 
@@ -239,9 +229,7 @@ impl<'tcx> Cx<'tcx> {
             let param_env_ty = self.param_env.and(discr_ty);
             let size = tcx
                 .layout_of(param_env_ty)
-                .unwrap_or_else(|e| {
-                    panic!("could not compute layout for {:?}: {:?}", param_env_ty, e)
-                })
+                .unwrap_or_else(|e| panic!("could not compute layout for {param_env_ty:?}: {e:?}"))
                 .size;
 
             let lit = ScalarInt::try_from_uint(discr_offset as u128, size).unwrap();
@@ -252,7 +240,7 @@ impl<'tcx> Cx<'tcx> {
                 // in case we are offsetting from a computed discriminant
                 // and not the beginning of discriminants (which is always `0`)
                 Some(did) => {
-                    let kind = ExprKind::NamedConst { def_id: did, substs, user_ty: None };
+                    let kind = ExprKind::NamedConst { def_id: did, args, user_ty: None };
                     let lhs =
                         self.thir.exprs.push(Expr { temp_lifetime, ty: discr_ty, span, kind });
                     let bin = ExprKind::Binary { op: BinOp::Add, lhs, rhs: offset };
@@ -274,7 +262,6 @@ impl<'tcx> Cx<'tcx> {
     fn make_mirror_unadjusted(&mut self, expr: &'tcx hir::Expr<'tcx>) -> Expr<'tcx> {
         let tcx = self.tcx;
         let expr_ty = self.typeck_results().expr_ty(expr);
-        let expr_span = expr.span;
         let temp_lifetime =
             self.rvalue_scopes.temporary_scope(self.region_scope_tree, expr.hir_id.local_id);
 
@@ -283,17 +270,11 @@ impl<'tcx> Cx<'tcx> {
             hir::ExprKind::MethodCall(segment, receiver, ref args, fn_span) => {
                 // Rewrite a.b(c) into UFCS form like Trait::b(a, c)
                 let expr = self.method_callee(expr, segment.ident.span, None);
-                // When we apply adjustments to the receiver, use the span of
-                // the overall method call for better diagnostics. args[0]
-                // is guaranteed to exist, since a method call always has a receiver.
-                let old_adjustment_span =
-                    self.adjustment_span.replace((receiver.hir_id, expr_span));
                 info!("Using method span: {:?}", expr.span);
                 let args = std::iter::once(receiver)
                     .chain(args.iter())
                     .map(|expr| self.mirror_expr(expr))
                     .collect();
-                self.adjustment_span = old_adjustment_span;
                 ExprKind::Call {
                     ty: expr.ty,
                     fun: self.thir.exprs.push(expr),
@@ -389,7 +370,7 @@ impl<'tcx> Cx<'tcx> {
                         None
                     };
                     if let Some((adt_def, index)) = adt_data {
-                        let substs = self.typeck_results().node_substs(fun.hir_id);
+                        let node_args = self.typeck_results().node_args(fun.hir_id);
                         let user_provided_types = self.typeck_results().user_provided_types();
                         let user_ty =
                             user_provided_types.get(fun.hir_id).copied().map(|mut u_ty| {
@@ -410,7 +391,7 @@ impl<'tcx> Cx<'tcx> {
                             .collect();
                         ExprKind::Adt(Box::new(AdtExpr {
                             adt_def,
-                            substs,
+                            args: node_args,
                             variant_index: index,
                             fields: field_refs,
                             user_ty,
@@ -464,7 +445,6 @@ impl<'tcx> Cx<'tcx> {
                     let rhs = self.mirror_expr(rhs);
                     self.overloaded_operator(expr, Box::new([lhs, rhs]))
                 } else {
-                    // FIXME overflow
                     match op.node {
                         hir::BinOpKind::And => ExprKind::LogicalOp {
                             op: LogicalOp::And,
@@ -488,11 +468,17 @@ impl<'tcx> Cx<'tcx> {
                 }
             }
 
-            hir::ExprKind::Index(ref lhs, ref index) => {
+            hir::ExprKind::Index(ref lhs, ref index, brackets_span) => {
                 if self.typeck_results().is_method_call(expr) {
                     let lhs = self.mirror_expr(lhs);
                     let index = self.mirror_expr(index);
-                    self.overloaded_place(expr, expr_ty, None, Box::new([lhs, index]), expr.span)
+                    self.overloaded_place(
+                        expr,
+                        expr_ty,
+                        None,
+                        Box::new([lhs, index]),
+                        brackets_span,
+                    )
                 } else {
                     ExprKind::Index { lhs: self.mirror_expr(lhs), index: self.mirror_expr(index) }
                 }
@@ -528,7 +514,7 @@ impl<'tcx> Cx<'tcx> {
             }
 
             hir::ExprKind::Struct(ref qpath, ref fields, ref base) => match expr_ty.kind() {
-                ty::Adt(adt, substs) => match adt.adt_kind() {
+                ty::Adt(adt, args) => match adt.adt_kind() {
                     AdtKind::Struct | AdtKind::Union => {
                         let user_provided_types = self.typeck_results().user_provided_types();
                         let user_ty = user_provided_types.get(expr.hir_id).copied().map(Box::new);
@@ -536,7 +522,7 @@ impl<'tcx> Cx<'tcx> {
                         ExprKind::Adt(Box::new(AdtExpr {
                             adt_def: *adt,
                             variant_index: FIRST_VARIANT,
-                            substs,
+                            args,
                             user_ty,
                             fields: self.field_refs(fields),
                             base: base.map(|base| FruInfo {
@@ -563,7 +549,7 @@ impl<'tcx> Cx<'tcx> {
                                 ExprKind::Adt(Box::new(AdtExpr {
                                     adt_def: *adt,
                                     variant_index: index,
-                                    substs,
+                                    args,
                                     user_ty,
                                     fields: self.field_refs(fields),
                                     base: None,
@@ -582,10 +568,10 @@ impl<'tcx> Cx<'tcx> {
 
             hir::ExprKind::Closure { .. } => {
                 let closure_ty = self.typeck_results().expr_ty(expr);
-                let (def_id, substs, movability) = match *closure_ty.kind() {
-                    ty::Closure(def_id, substs) => (def_id, UpvarSubsts::Closure(substs), None),
-                    ty::Generator(def_id, substs, movability) => {
-                        (def_id, UpvarSubsts::Generator(substs), Some(movability))
+                let (def_id, args, movability) = match *closure_ty.kind() {
+                    ty::Closure(def_id, args) => (def_id, UpvarArgs::Closure(args), None),
+                    ty::Generator(def_id, args, movability) => {
+                        (def_id, UpvarArgs::Generator(args), Some(movability))
                     }
                     _ => {
                         span_bug!(expr.span, "closure expr w/o closure type: {:?}", closure_ty);
@@ -597,7 +583,7 @@ impl<'tcx> Cx<'tcx> {
                     .tcx
                     .closure_captures(def_id)
                     .iter()
-                    .zip(substs.upvar_tys())
+                    .zip(args.upvar_tys())
                     .map(|(captured_place, ty)| {
                         let upvars = self.capture_upvar(expr, captured_place, ty);
                         self.thir.exprs.push(upvars)
@@ -618,7 +604,7 @@ impl<'tcx> Cx<'tcx> {
 
                 ExprKind::Closure(Box::new(ClosureExpr {
                     closure_id: def_id,
-                    substs,
+                    args,
                     upvars,
                     movability,
                     fake_reads,
@@ -701,13 +687,11 @@ impl<'tcx> Cx<'tcx> {
                 let ty = self.typeck_results().node_type(anon_const.hir_id);
                 let did = anon_const.def_id.to_def_id();
                 let typeck_root_def_id = tcx.typeck_root_def_id(did);
-                let parent_substs =
-                    tcx.erase_regions(InternalSubsts::identity_for_item(tcx, typeck_root_def_id));
-                let substs =
-                    InlineConstSubsts::new(tcx, InlineConstSubstsParts { parent_substs, ty })
-                        .substs;
+                let parent_args =
+                    tcx.erase_regions(GenericArgs::identity_for_item(tcx, typeck_root_def_id));
+                let args = InlineConstArgs::new(tcx, InlineConstArgsParts { parent_args, ty }).args;
 
-                ExprKind::ConstBlock { did, substs }
+                ExprKind::ConstBlock { did, args }
             }
             // Now comes the rote stuff:
             hir::ExprKind::Repeat(ref v, _) => {
@@ -748,6 +732,7 @@ impl<'tcx> Cx<'tcx> {
             },
             hir::ExprKind::Match(ref discr, ref arms, _) => ExprKind::Match {
                 scrutinee: self.mirror_expr(discr),
+                scrutinee_hir_id: discr.hir_id,
                 arms: arms.iter().map(|a| self.convert_arm(a)).collect(),
             },
             hir::ExprKind::Loop(ref body, ..) => {
@@ -826,12 +811,12 @@ impl<'tcx> Cx<'tcx> {
         Expr { temp_lifetime, ty: expr_ty, span: expr.span, kind }
     }
 
-    fn user_substs_applied_to_res(
+    fn user_args_applied_to_res(
         &mut self,
         hir_id: hir::HirId,
         res: Res,
     ) -> Option<Box<ty::CanonicalUserType<'tcx>>> {
-        debug!("user_substs_applied_to_res: res={:?}", res);
+        debug!("user_args_applied_to_res: res={:?}", res);
         let user_provided_type = match res {
             // A reference to something callable -- e.g., a fn, method, or
             // a tuple-struct or tuple-variant. This has the type of a
@@ -849,15 +834,15 @@ impl<'tcx> Cx<'tcx> {
             // this variant -- but with the substitutions given by the
             // user.
             Res::Def(DefKind::Ctor(_, CtorKind::Const), _) => {
-                self.user_substs_applied_to_ty_of_hir_id(hir_id).map(Box::new)
+                self.user_args_applied_to_ty_of_hir_id(hir_id).map(Box::new)
             }
 
             // `Self` is used in expression as a tuple struct constructor or a unit struct constructor
-            Res::SelfCtor(_) => self.user_substs_applied_to_ty_of_hir_id(hir_id).map(Box::new),
+            Res::SelfCtor(_) => self.user_args_applied_to_ty_of_hir_id(hir_id).map(Box::new),
 
-            _ => bug!("user_substs_applied_to_res: unexpected res {:?} at {:?}", res, hir_id),
+            _ => bug!("user_args_applied_to_res: unexpected res {:?} at {:?}", res, hir_id),
         };
-        debug!("user_substs_applied_to_res: user_provided_type={:?}", user_provided_type);
+        debug!("user_args_applied_to_res: user_provided_type={:?}", user_provided_type);
         user_provided_type
     }
 
@@ -876,13 +861,13 @@ impl<'tcx> Cx<'tcx> {
                     self.typeck_results().type_dependent_def(expr.hir_id).unwrap_or_else(|| {
                         span_bug!(expr.span, "no type-dependent def for method callee")
                     });
-                let user_ty = self.user_substs_applied_to_res(expr.hir_id, Res::Def(kind, def_id));
+                let user_ty = self.user_args_applied_to_res(expr.hir_id, Res::Def(kind, def_id));
                 debug!("method_callee: user_ty={:?}", user_ty);
                 (
                     Ty::new_fn_def(
                         self.tcx(),
                         def_id,
-                        self.typeck_results().node_substs(expr.hir_id),
+                        self.typeck_results().node_args(expr.hir_id),
                     ),
                     user_ty,
                 )
@@ -909,14 +894,14 @@ impl<'tcx> Cx<'tcx> {
     }
 
     fn convert_path_expr(&mut self, expr: &'tcx hir::Expr<'tcx>, res: Res) -> ExprKind<'tcx> {
-        let substs = self.typeck_results().node_substs(expr.hir_id);
+        let args = self.typeck_results().node_args(expr.hir_id);
         match res {
             // A regular function, constructor function or a constant.
             Res::Def(DefKind::Fn, _)
             | Res::Def(DefKind::AssocFn, _)
             | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _)
             | Res::SelfCtor(_) => {
-                let user_ty = self.user_substs_applied_to_res(expr.hir_id, res);
+                let user_ty = self.user_args_applied_to_res(expr.hir_id, res);
                 ExprKind::ZstLiteral { user_ty }
             }
 
@@ -931,8 +916,8 @@ impl<'tcx> Cx<'tcx> {
             }
 
             Res::Def(DefKind::Const, def_id) | Res::Def(DefKind::AssocConst, def_id) => {
-                let user_ty = self.user_substs_applied_to_res(expr.hir_id, res);
-                ExprKind::NamedConst { def_id, substs, user_ty }
+                let user_ty = self.user_args_applied_to_res(expr.hir_id, res);
+                ExprKind::NamedConst { def_id, args, user_ty }
             }
 
             Res::Def(DefKind::Ctor(_, CtorKind::Const), def_id) => {
@@ -943,10 +928,10 @@ impl<'tcx> Cx<'tcx> {
                 match ty.kind() {
                     // A unit struct/variant which is used as a value.
                     // We return a completely different ExprKind here to account for this special case.
-                    ty::Adt(adt_def, substs) => ExprKind::Adt(Box::new(AdtExpr {
+                    ty::Adt(adt_def, args) => ExprKind::Adt(Box::new(AdtExpr {
                         adt_def: *adt_def,
                         variant_index: adt_def.variant_index_with_ctor_id(def_id),
-                        substs,
+                        args,
                         user_ty,
                         fields: Box::new([]),
                         base: None,
@@ -1093,6 +1078,9 @@ impl<'tcx> Cx<'tcx> {
                     variant_index,
                     name: field,
                 },
+                HirProjectionKind::OpaqueCast => {
+                    ExprKind::Use { source: self.thir.exprs.push(captured_place_expr) }
+                }
                 HirProjectionKind::Index | HirProjectionKind::Subslice => {
                     // We don't capture these projections, so we can ignore them here
                     continue;
diff --git a/compiler/rustc_mir_build/src/thir/cx/mod.rs b/compiler/rustc_mir_build/src/thir/cx/mod.rs
index e6a98d1aa..d98cc76ad 100644
--- a/compiler/rustc_mir_build/src/thir/cx/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/mod.rs
@@ -16,7 +16,6 @@ use rustc_hir::Node;
 use rustc_middle::middle::region;
 use rustc_middle::thir::*;
 use rustc_middle::ty::{self, RvalueScopes, Ty, TyCtxt};
-use rustc_span::Span;
 
 pub(crate) fn thir_body(
     tcx: TyCtxt<'_>,
@@ -62,14 +61,6 @@ struct Cx<'tcx> {
     typeck_results: &'tcx ty::TypeckResults<'tcx>,
     rvalue_scopes: &'tcx RvalueScopes,
 
-    /// When applying adjustments to the expression
-    /// with the given `HirId`, use the given `Span`,
-    /// instead of the usual span. This is used to
-    /// assign the span of an overall method call
-    /// (e.g. `my_val.foo()`) to the adjustment expressions
-    /// for the receiver.
-    adjustment_span: Option<(HirId, Span)>,
-
     /// False to indicate that adjustments should not be applied. Only used for `custom_mir`
     apply_adjustments: bool,
 
@@ -110,7 +101,6 @@ impl<'tcx> Cx<'tcx> {
             typeck_results,
             rvalue_scopes: &typeck_results.rvalue_scopes,
             body_owner: def.to_def_id(),
-            adjustment_span: None,
             apply_adjustments: hir
                 .attrs(hir_id)
                 .iter()
@@ -132,7 +122,7 @@ impl<'tcx> Cx<'tcx> {
             DefKind::Closure => {
                 let closure_ty = self.typeck_results.node_type(owner_id);
 
-                let ty::Closure(closure_def_id, closure_substs) = *closure_ty.kind() else {
+                let ty::Closure(closure_def_id, closure_args) = *closure_ty.kind() else {
                     bug!("closure expr does not have closure type: {:?}", closure_ty);
                 };
 
@@ -144,7 +134,7 @@ impl<'tcx> Cx<'tcx> {
                 };
                 let env_region = ty::Region::new_late_bound(self.tcx, ty::INNERMOST, br);
                 let closure_env_ty =
-                    self.tcx.closure_env_ty(closure_def_id, closure_substs, env_region).unwrap();
+                    self.tcx.closure_env_ty(closure_def_id, closure_args, env_region).unwrap();
                 let liberated_closure_env_ty = self.tcx.erase_late_bound_regions(
                     ty::Binder::bind_with_vars(closure_env_ty, bound_vars),
                 );
@@ -196,7 +186,7 @@ impl<'tcx> Cx<'tcx> {
 
                 self.tcx
                     .type_of(va_list_did)
-                    .subst(self.tcx, &[self.tcx.lifetimes.re_erased.into()])
+                    .instantiate(self.tcx, &[self.tcx.lifetimes.re_erased.into()])
             } else {
                 fn_sig.inputs()[index]
             };
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index ef60f08bf..383e80851 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -135,10 +135,12 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for MatchVisitor<'a, '_, 'tcx> {
                 });
                 return;
             }
-            ExprKind::Match { scrutinee, box ref arms } => {
+            ExprKind::Match { scrutinee, scrutinee_hir_id, box ref arms } => {
                 let source = match ex.span.desugaring_kind() {
                     Some(DesugaringKind::ForLoop) => hir::MatchSource::ForLoopDesugar,
-                    Some(DesugaringKind::QuestionMark) => hir::MatchSource::TryDesugar,
+                    Some(DesugaringKind::QuestionMark) => {
+                        hir::MatchSource::TryDesugar(scrutinee_hir_id)
+                    }
                     Some(DesugaringKind::Await) => hir::MatchSource::AwaitDesugar,
                     _ => hir::MatchSource::Normal,
                 };
@@ -277,7 +279,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
             | hir::MatchSource::FormatArgs => report_arm_reachability(&cx, &report),
             // Unreachable patterns in try and await expressions occur when one of
             // the arms are an uninhabited type. Which is OK.
-            hir::MatchSource::AwaitDesugar | hir::MatchSource::TryDesugar => {}
+            hir::MatchSource::AwaitDesugar | hir::MatchSource::TryDesugar(_) => {}
         }
 
         // Check if the match is exhaustive.
@@ -501,12 +503,12 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
         let witness_1_is_privately_uninhabited =
             if cx.tcx.features().exhaustive_patterns
                 && let Some(witness_1) = witnesses.get(0)
-                && let ty::Adt(adt, substs) = witness_1.ty().kind()
+                && let ty::Adt(adt, args) = witness_1.ty().kind()
                 && adt.is_enum()
                 && let Constructor::Variant(variant_index) = witness_1.ctor()
             {
                 let variant = adt.variant(*variant_index);
-                let inhabited = variant.inhabited_predicate(cx.tcx, *adt).subst(cx.tcx, substs);
+                let inhabited = variant.inhabited_predicate(cx.tcx, *adt).instantiate(cx.tcx, args);
                 assert!(inhabited.apply(cx.tcx, cx.param_env, cx.module));
                 !inhabited.apply_ignore_module(cx.tcx, cx.param_env)
             } else {
@@ -691,7 +693,7 @@ fn non_exhaustive_match<'p, 'tcx>(
         err = create_e0004(
             cx.tcx.sess,
             sp,
-            format!("non-exhaustive patterns: {} not covered", joined_patterns),
+            format!("non-exhaustive patterns: {joined_patterns} not covered"),
         );
         err.span_label(sp, pattern_not_covered_label(&witnesses, &joined_patterns));
         patterns_len = witnesses.len();
@@ -721,15 +723,13 @@ fn non_exhaustive_match<'p, 'tcx>(
         && matches!(witnesses[0].ctor(), Constructor::NonExhaustive)
     {
         err.note(format!(
-            "`{}` does not have a fixed maximum value, so a wildcard `_` is necessary to match \
+            "`{scrut_ty}` does not have a fixed maximum value, so a wildcard `_` is necessary to match \
              exhaustively",
-            scrut_ty,
         ));
         if cx.tcx.sess.is_nightly_build() {
             err.help(format!(
                 "add `#![feature(precise_pointer_size_matching)]` to the crate attributes to \
-                 enable precise `{}` matching",
-                scrut_ty,
+                 enable precise `{scrut_ty}` matching",
             ));
         }
     }
@@ -745,18 +745,13 @@ fn non_exhaustive_match<'p, 'tcx>(
         [] if sp.eq_ctxt(expr_span) => {
             // Get the span for the empty match body `{}`.
             let (indentation, more) = if let Some(snippet) = sm.indentation_before(sp) {
-                (format!("\n{}", snippet), "    ")
+                (format!("\n{snippet}"), "    ")
             } else {
                 (" ".to_string(), "")
             };
             suggestion = Some((
                 sp.shrink_to_hi().with_hi(expr_span.hi()),
-                format!(
-                    " {{{indentation}{more}{pattern} => todo!(),{indentation}}}",
-                    indentation = indentation,
-                    more = more,
-                    pattern = pattern,
-                ),
+                format!(" {{{indentation}{more}{pattern} => todo!(),{indentation}}}",),
             ));
         }
         [only] => {
@@ -765,7 +760,7 @@ fn non_exhaustive_match<'p, 'tcx>(
                 && let Ok(with_trailing) = sm.span_extend_while(only.span, |c| c.is_whitespace() || c == ',')
                 && sm.is_multiline(with_trailing)
             {
-                (format!("\n{}", snippet), true)
+                (format!("\n{snippet}"), true)
             } else {
                 (" ".to_string(), false)
             };
@@ -780,7 +775,7 @@ fn non_exhaustive_match<'p, 'tcx>(
             };
             suggestion = Some((
                 only.span.shrink_to_hi(),
-                format!("{}{}{} => todo!()", comma, pre_indentation, pattern),
+                format!("{comma}{pre_indentation}{pattern} => todo!()"),
             ));
         }
         [.., prev, last] => {
@@ -803,7 +798,7 @@ fn non_exhaustive_match<'p, 'tcx>(
                 if let Some(spacing) = spacing {
                     suggestion = Some((
                         last.span.shrink_to_hi(),
-                        format!("{}{}{} => todo!()", comma, spacing, pattern),
+                        format!("{comma}{spacing}{pattern} => todo!()"),
                     ));
                 }
             }
@@ -900,7 +895,7 @@ fn adt_defined_here<'p, 'tcx>(
         for pat in spans {
             span.push_span_label(pat, "not covered");
         }
-        err.span_note(span, format!("`{}` defined here", ty));
+        err.span_note(span, format!("`{ty}` defined here"));
     }
 }
 
@@ -942,7 +937,9 @@ fn maybe_point_at_variant<'a, 'p: 'a, 'tcx: 'a>(
 /// This analysis is *not* subsumed by NLL.
 fn check_borrow_conflicts_in_at_patterns<'tcx>(cx: &MatchVisitor<'_, '_, 'tcx>, pat: &Pat<'tcx>) {
     // Extract `sub` in `binding @ sub`.
-    let PatKind::Binding { name, mode, ty, subpattern: Some(box ref sub), .. } = pat.kind else { return };
+    let PatKind::Binding { name, mode, ty, subpattern: Some(box ref sub), .. } = pat.kind else {
+        return;
+    };
 
     let is_binding_by_move = |ty: Ty<'tcx>| !ty.is_copy_modulo_regions(cx.tcx, cx.param_env);
 
diff --git a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
index 050b01294..1376344cf 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
@@ -325,6 +325,11 @@ impl<'tcx> ConstToPat<'tcx> {
                 // `PartialEq::eq` on it.
                 return Err(FallbackToConstRef);
             }
+            ty::FnDef(..) => {
+                self.saw_const_match_error.set(true);
+                tcx.sess.emit_err(InvalidPattern { span, non_sm_ty: ty });
+                PatKind::Wild
+            }
             ty::Adt(adt_def, _) if !self.type_marked_structural(ty) => {
                 debug!("adt_def {:?} has !type_marked_structural for cv.ty: {:?}", adt_def, ty,);
                 self.saw_const_match_error.set(true);
@@ -332,20 +337,20 @@ impl<'tcx> ConstToPat<'tcx> {
                 tcx.sess.emit_err(err);
                 PatKind::Wild
             }
-            ty::Adt(adt_def, substs) if adt_def.is_enum() => {
+            ty::Adt(adt_def, args) if adt_def.is_enum() => {
                 let (&variant_index, fields) = cv.unwrap_branch().split_first().unwrap();
                 let variant_index =
                     VariantIdx::from_u32(variant_index.unwrap_leaf().try_to_u32().ok().unwrap());
                 PatKind::Variant {
                     adt_def: *adt_def,
-                    substs,
+                    args,
                     variant_index,
                     subpatterns: self.field_pats(
                         fields.iter().copied().zip(
                             adt_def.variants()[variant_index]
                                 .fields
                                 .iter()
-                                .map(|field| field.ty(self.tcx(), substs)),
+                                .map(|field| field.ty(self.tcx(), args)),
                         ),
                     )?,
                 }
@@ -354,9 +359,9 @@ impl<'tcx> ConstToPat<'tcx> {
                 subpatterns: self
                     .field_pats(cv.unwrap_branch().iter().copied().zip(fields.iter()))?,
             },
-            ty::Adt(def, substs) => PatKind::Leaf {
+            ty::Adt(def, args) => PatKind::Leaf {
                 subpatterns: self.field_pats(cv.unwrap_branch().iter().copied().zip(
-                    def.non_enum_variant().fields.iter().map(|field| field.ty(self.tcx(), substs)),
+                    def.non_enum_variant().fields.iter().map(|field| field.ty(self.tcx(), args)),
                 ))?,
             },
             ty::Slice(elem_ty) => PatKind::Slice {
@@ -440,7 +445,7 @@ impl<'tcx> ConstToPat<'tcx> {
                     }
                 }
             },
-            ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::FnDef(..) => PatKind::Constant {
+            ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) => PatKind::Constant {
                 value: mir::ConstantKind::Ty(ty::Const::new_value(tcx, cv, ty)),
             },
             ty::FnPtr(..) | ty::RawPtr(..) => unreachable!(),
diff --git a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
index 9df6d2f43..bee1c4e46 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
@@ -306,9 +306,9 @@ impl fmt::Debug for IntRange {
         let (lo, hi) = self.boundaries();
         let bias = self.bias;
         let (lo, hi) = (lo ^ bias, hi ^ bias);
-        write!(f, "{}", lo)?;
+        write!(f, "{lo}")?;
         write!(f, "{}", RangeEnd::Included)?;
-        write!(f, "{}", hi)
+        write!(f, "{hi}")
     }
 }
 
@@ -922,7 +922,7 @@ impl<'tcx> SplitWildcard<'tcx> {
                 let kind = if cx.is_uninhabited(*sub_ty) { FixedLen(0) } else { VarLen(0, 0) };
                 smallvec![Slice(Slice::new(None, kind))]
             }
-            ty::Adt(def, substs) if def.is_enum() => {
+            ty::Adt(def, args) if def.is_enum() => {
                 // If the enum is declared as `#[non_exhaustive]`, we treat it as if it had an
                 // additional "unknown" constructor.
                 // There is no point in enumerating all possible variants, because the user can't
@@ -950,21 +950,19 @@ impl<'tcx> SplitWildcard<'tcx> {
                 let is_secretly_empty =
                     def.variants().is_empty() && !is_exhaustive_pat_feature && !pcx.is_top_level;
 
-                let mut ctors: SmallVec<[_; 1]> = def
-                    .variants()
-                    .iter_enumerated()
-                    .filter(|(_, v)| {
-                        // If `exhaustive_patterns` is enabled, we exclude variants known to be
-                        // uninhabited.
-                        !is_exhaustive_pat_feature
-                            || v.inhabited_predicate(cx.tcx, *def).subst(cx.tcx, substs).apply(
-                                cx.tcx,
-                                cx.param_env,
-                                cx.module,
-                            )
-                    })
-                    .map(|(idx, _)| Variant(idx))
-                    .collect();
+                let mut ctors: SmallVec<[_; 1]> =
+                    def.variants()
+                        .iter_enumerated()
+                        .filter(|(_, v)| {
+                            // If `exhaustive_patterns` is enabled, we exclude variants known to be
+                            // uninhabited.
+                            !is_exhaustive_pat_feature
+                                || v.inhabited_predicate(cx.tcx, *def)
+                                    .instantiate(cx.tcx, args)
+                                    .apply(cx.tcx, cx.param_env, cx.module)
+                        })
+                        .map(|(idx, _)| Variant(idx))
+                        .collect();
 
                 if is_secretly_empty || is_declared_nonexhaustive {
                     ctors.push(NonExhaustive);
@@ -1156,12 +1154,12 @@ impl<'p, 'tcx> Fields<'p, 'tcx> {
         ty: Ty<'tcx>,
         variant: &'a VariantDef,
     ) -> impl Iterator<Item = (FieldIdx, Ty<'tcx>)> + Captures<'a> + Captures<'p> {
-        let ty::Adt(adt, substs) = ty.kind() else { bug!() };
+        let ty::Adt(adt, args) = ty.kind() else { bug!() };
         // Whether we must not match the fields of this variant exhaustively.
         let is_non_exhaustive = variant.is_field_list_non_exhaustive() && !adt.did().is_local();
 
         variant.fields.iter().enumerate().filter_map(move |(i, field)| {
-            let ty = field.ty(cx.tcx, substs);
+            let ty = field.ty(cx.tcx, args);
             // `field.ty()` doesn't normalize after substituting.
             let ty = cx.tcx.normalize_erasing_regions(cx.param_env, ty);
             let is_visible = adt.is_enum() || field.vis.is_accessible_from(cx.module, cx.tcx);
@@ -1183,11 +1181,11 @@ impl<'p, 'tcx> Fields<'p, 'tcx> {
             Single | Variant(_) => match pcx.ty.kind() {
                 ty::Tuple(fs) => Fields::wildcards_from_tys(pcx.cx, fs.iter(), pcx.span),
                 ty::Ref(_, rty, _) => Fields::wildcards_from_tys(pcx.cx, once(*rty), pcx.span),
-                ty::Adt(adt, substs) => {
+                ty::Adt(adt, args) => {
                     if adt.is_box() {
                         // The only legal patterns of type `Box` (outside `std`) are `_` and box
                         // patterns. If we're here we can assume this is a box pattern.
-                        Fields::wildcards_from_tys(pcx.cx, once(substs.type_at(0)), pcx.span)
+                        Fields::wildcards_from_tys(pcx.cx, once(args.type_at(0)), pcx.span)
                     } else {
                         let variant = &adt.variant(constructor.variant_index_for_adt(*adt));
                         let tys = Fields::list_variant_nonhidden_fields(pcx.cx, pcx.ty, variant)
@@ -1294,7 +1292,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                         }
                         fields = Fields::from_iter(cx, wilds);
                     }
-                    ty::Adt(adt, substs) if adt.is_box() => {
+                    ty::Adt(adt, args) if adt.is_box() => {
                         // The only legal patterns of type `Box` (outside `std`) are `_` and box
                         // patterns. If we're here we can assume this is a box pattern.
                         // FIXME(Nadrieril): A `Box` can in theory be matched either with `Box(_,
@@ -1311,7 +1309,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                         let pat = if let Some(pat) = pattern {
                             mkpat(&pat.pattern)
                         } else {
-                            DeconstructedPat::wildcard(substs.type_at(0), pat.span)
+                            DeconstructedPat::wildcard(args.type_at(0), pat.span)
                         };
                         ctor = Single;
                         fields = Fields::singleton(cx, pat);
@@ -1437,7 +1435,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                     // the pattern is a box pattern.
                     PatKind::Deref { subpattern: subpatterns.next().unwrap() }
                 }
-                ty::Adt(adt_def, substs) => {
+                ty::Adt(adt_def, args) => {
                     let variant_index = self.ctor.variant_index_for_adt(*adt_def);
                     let variant = &adt_def.variant(variant_index);
                     let subpatterns = Fields::list_variant_nonhidden_fields(cx, self.ty, variant)
@@ -1446,7 +1444,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                         .collect();
 
                     if adt_def.is_enum() {
-                        PatKind::Variant { adt_def: *adt_def, substs, variant_index, subpatterns }
+                        PatKind::Variant { adt_def: *adt_def, args, variant_index, subpatterns }
                     } else {
                         PatKind::Leaf { subpatterns }
                     }
@@ -1621,7 +1619,7 @@ impl<'p, 'tcx> fmt::Debug for DeconstructedPat<'p, 'tcx> {
                     // of `std`). So this branch is only reachable when the feature is enabled and
                     // the pattern is a box pattern.
                     let subpattern = self.iter_fields().next().unwrap();
-                    write!(f, "box {:?}", subpattern)
+                    write!(f, "box {subpattern:?}")
                 }
                 ty::Adt(..) | ty::Tuple(..) => {
                     let variant = match self.ty.kind() {
@@ -1640,7 +1638,7 @@ impl<'p, 'tcx> fmt::Debug for DeconstructedPat<'p, 'tcx> {
                     write!(f, "(")?;
                     for p in self.iter_fields() {
                         write!(f, "{}", start_or_comma())?;
-                        write!(f, "{:?}", p)?;
+                        write!(f, "{p:?}")?;
                     }
                     write!(f, ")")
                 }
@@ -1676,11 +1674,11 @@ impl<'p, 'tcx> fmt::Debug for DeconstructedPat<'p, 'tcx> {
                 write!(f, "]")
             }
             &FloatRange(lo, hi, end) => {
-                write!(f, "{}", lo)?;
-                write!(f, "{}", end)?;
-                write!(f, "{}", hi)
+                write!(f, "{lo}")?;
+                write!(f, "{end}")?;
+                write!(f, "{hi}")
             }
-            IntRange(range) => write!(f, "{:?}", range), // Best-effort, will render e.g. `false` as `0..=0`
+            IntRange(range) => write!(f, "{range:?}"), // Best-effort, will render e.g. `false` as `0..=0`
             Wildcard | Missing { .. } | NonExhaustive => write!(f, "_ : {:?}", self.ty),
             Or => {
                 for pat in self.iter_fields() {
@@ -1688,7 +1686,7 @@ impl<'p, 'tcx> fmt::Debug for DeconstructedPat<'p, 'tcx> {
                 }
                 Ok(())
             }
-            Str(value) => write!(f, "{}", value),
+            Str(value) => write!(f, "{value}"),
             Opaque => write!(f, "<constant pattern>"),
         }
     }
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index 600995927..c08fe54c3 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -23,10 +23,10 @@ use rustc_middle::mir::interpret::{
 use rustc_middle::mir::{self, ConstantKind, UserTypeProjection};
 use rustc_middle::mir::{BorrowKind, Mutability};
 use rustc_middle::thir::{Ascription, BindingMode, FieldPat, LocalVarId, Pat, PatKind, PatRange};
-use rustc_middle::ty::subst::{GenericArg, SubstsRef};
 use rustc_middle::ty::CanonicalUserTypeAnnotation;
 use rustc_middle::ty::TypeVisitableExt;
 use rustc_middle::ty::{self, AdtDef, Region, Ty, TyCtxt, UserType};
+use rustc_middle::ty::{GenericArg, GenericArgsRef};
 use rustc_span::{Span, Symbol};
 use rustc_target::abi::FieldIdx;
 
@@ -416,8 +416,8 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 let enum_id = self.tcx.parent(variant_id);
                 let adt_def = self.tcx.adt_def(enum_id);
                 if adt_def.is_enum() {
-                    let substs = match ty.kind() {
-                        ty::Adt(_, substs) | ty::FnDef(_, substs) => substs,
+                    let args = match ty.kind() {
+                        ty::Adt(_, args) | ty::FnDef(_, args) => args,
                         ty::Error(_) => {
                             // Avoid ICE (#50585)
                             return PatKind::Wild;
@@ -426,7 +426,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                     };
                     PatKind::Variant {
                         adt_def,
-                        substs,
+                        args,
                         variant_index: adt_def.variant_index_with_id(variant_id),
                         subpatterns,
                     }
@@ -439,7 +439,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 DefKind::Struct
                 | DefKind::Ctor(CtorOf::Struct, ..)
                 | DefKind::Union
-                | DefKind::TyAlias
+                | DefKind::TyAlias { .. }
                 | DefKind::AssocTy,
                 _,
             )
@@ -460,7 +460,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
             }
         };
 
-        if let Some(user_ty) = self.user_substs_applied_to_ty_of_hir_id(hir_id) {
+        if let Some(user_ty) = self.user_args_applied_to_ty_of_hir_id(hir_id) {
             debug!("lower_variant_or_leaf: kind={:?} user_ty={:?} span={:?}", kind, user_ty, span);
             let annotation = CanonicalUserTypeAnnotation {
                 user_ty: Box::new(user_ty),
@@ -496,13 +496,13 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         // Use `Reveal::All` here because patterns are always monomorphic even if their function
         // isn't.
         let param_env_reveal_all = self.param_env.with_reveal_all_normalized(self.tcx);
-        // N.B. There is no guarantee that substs collected in typeck results are fully normalized,
+        // N.B. There is no guarantee that args collected in typeck results are fully normalized,
         // so they need to be normalized in order to pass to `Instance::resolve`, which will ICE
         // if given unnormalized types.
-        let substs = self
+        let args = self
             .tcx
-            .normalize_erasing_regions(param_env_reveal_all, self.typeck_results.node_substs(id));
-        let instance = match ty::Instance::resolve(self.tcx, param_env_reveal_all, def_id, substs) {
+            .normalize_erasing_regions(param_env_reveal_all, self.typeck_results.node_args(id));
+        let instance = match ty::Instance::resolve(self.tcx, param_env_reveal_all, def_id, args) {
             Ok(Some(i)) => i,
             Ok(None) => {
                 // It should be assoc consts if there's no error but we cannot resolve it.
@@ -617,16 +617,14 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         }
 
         let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id());
-        let parent_substs =
-            tcx.erase_regions(ty::InternalSubsts::identity_for_item(tcx, typeck_root_def_id));
-        let substs =
-            ty::InlineConstSubsts::new(tcx, ty::InlineConstSubstsParts { parent_substs, ty })
-                .substs;
+        let parent_args =
+            tcx.erase_regions(ty::GenericArgs::identity_for_item(tcx, typeck_root_def_id));
+        let args = ty::InlineConstArgs::new(tcx, ty::InlineConstArgsParts { parent_args, ty }).args;
 
-        let uneval = mir::UnevaluatedConst { def: def_id.to_def_id(), substs, promoted: None };
-        debug_assert!(!substs.has_free_regions());
+        let uneval = mir::UnevaluatedConst { def: def_id.to_def_id(), args, promoted: None };
+        debug_assert!(!args.has_free_regions());
 
-        let ct = ty::UnevaluatedConst { def: def_id.to_def_id(), substs: substs };
+        let ct = ty::UnevaluatedConst { def: def_id.to_def_id(), args: args };
         // First try using a valtree in order to destructure the constant into a pattern.
         if let Ok(Some(valtree)) =
             self.tcx.const_eval_resolve_for_typeck(self.param_env, ct, Some(span))
@@ -754,7 +752,7 @@ macro_rules! ClonePatternFoldableImpls {
 ClonePatternFoldableImpls! { <'tcx>
     Span, FieldIdx, Mutability, Symbol, LocalVarId, usize,
     Region<'tcx>, Ty<'tcx>, BindingMode, AdtDef<'tcx>,
-    SubstsRef<'tcx>, &'tcx GenericArg<'tcx>, UserType<'tcx>,
+    GenericArgsRef<'tcx>, &'tcx GenericArg<'tcx>, UserType<'tcx>,
     UserTypeProjection, CanonicalUserTypeAnnotation<'tcx>
 }
 
@@ -804,10 +802,10 @@ impl<'tcx> PatternFoldable<'tcx> for PatKind<'tcx> {
                     is_primary,
                 }
             }
-            PatKind::Variant { adt_def, substs, variant_index, ref subpatterns } => {
+            PatKind::Variant { adt_def, args, variant_index, ref subpatterns } => {
                 PatKind::Variant {
                     adt_def: adt_def.fold_with(folder),
-                    substs: substs.fold_with(folder),
+                    args: args.fold_with(folder),
                     variant_index,
                     subpatterns: subpatterns.fold_with(folder),
                 }
diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
index e5b635069..08cfe98bb 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
@@ -459,7 +459,7 @@ impl<'p, 'tcx> fmt::Debug for PatStack<'p, 'tcx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "+")?;
         for pat in self.iter() {
-            write!(f, " {:?} +", pat)?;
+            write!(f, " {pat:?} +")?;
         }
         Ok(())
     }
@@ -530,7 +530,7 @@ impl<'p, 'tcx> fmt::Debug for Matrix<'p, 'tcx> {
 
         let Matrix { patterns: m, .. } = self;
         let pretty_printed_matrix: Vec<Vec<String>> =
-            m.iter().map(|row| row.iter().map(|pat| format!("{:?}", pat)).collect()).collect();
+            m.iter().map(|row| row.iter().map(|pat| format!("{pat:?}")).collect()).collect();
 
         let column_count = m.iter().map(|row| row.len()).next().unwrap_or(0);
         assert!(m.iter().all(|row| row.len() == column_count));
diff --git a/compiler/rustc_mir_build/src/thir/print.rs b/compiler/rustc_mir_build/src/thir/print.rs
index 8d7c624a8..3b6276cfe 100644
--- a/compiler/rustc_mir_build/src/thir/print.rs
+++ b/compiler/rustc_mir_build/src/thir/print.rs
@@ -321,7 +321,7 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
                 print_indented!(self, format!("pat: {:?}", pat), depth_lvl + 1);
                 print_indented!(self, "}", depth_lvl);
             }
-            Match { scrutinee, arms } => {
+            Match { scrutinee, arms, .. } => {
                 print_indented!(self, "Match {", depth_lvl);
                 print_indented!(self, "scrutinee:", depth_lvl + 1);
                 self.print_expr(*scrutinee, depth_lvl + 2);
@@ -427,10 +427,10 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
                 self.print_expr(*value, depth_lvl + 2);
                 print_indented!(self, "}", depth_lvl);
             }
-            ConstBlock { did, substs } => {
+            ConstBlock { did, args } => {
                 print_indented!(self, "ConstBlock {", depth_lvl);
                 print_indented!(self, format!("did: {:?}", did), depth_lvl + 1);
-                print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 1);
+                print_indented!(self, format!("args: {:?}", args), depth_lvl + 1);
                 print_indented!(self, "}", depth_lvl);
             }
             Repeat { value, count } => {
@@ -499,11 +499,11 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
             ZstLiteral { user_ty } => {
                 print_indented!(self, format!("ZstLiteral(user_ty: {:?})", user_ty), depth_lvl);
             }
-            NamedConst { def_id, substs, user_ty } => {
+            NamedConst { def_id, args, user_ty } => {
                 print_indented!(self, "NamedConst {", depth_lvl);
                 print_indented!(self, format!("def_id: {:?}", def_id), depth_lvl + 1);
                 print_indented!(self, format!("user_ty: {:?}", user_ty), depth_lvl + 1);
-                print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 1);
+                print_indented!(self, format!("args: {:?}", args), depth_lvl + 1);
                 print_indented!(self, "}", depth_lvl);
             }
             ConstParam { param, def_id } => {
@@ -560,7 +560,7 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
             format!("variant_index: {:?}", adt_expr.variant_index),
             depth_lvl + 1
         );
-        print_indented!(self, format!("substs: {:?}", adt_expr.substs), depth_lvl + 1);
+        print_indented!(self, format!("args: {:?}", adt_expr.args), depth_lvl + 1);
         print_indented!(self, format!("user_ty: {:?}", adt_expr.user_ty), depth_lvl + 1);
 
         for (i, field_expr) in adt_expr.fields.iter().enumerate() {
@@ -662,11 +662,11 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
 
                 print_indented!(self, "}", depth_lvl + 1);
             }
-            PatKind::Variant { adt_def, substs, variant_index, subpatterns } => {
+            PatKind::Variant { adt_def, args, variant_index, subpatterns } => {
                 print_indented!(self, "Variant {", depth_lvl + 1);
                 print_indented!(self, "adt_def: ", depth_lvl + 2);
                 self.print_adt_def(*adt_def, depth_lvl + 3);
-                print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 2);
+                print_indented!(self, format!("args: {:?}", args), depth_lvl + 2);
                 print_indented!(self, format!("variant_index: {:?}", variant_index), depth_lvl + 2);
 
                 if subpatterns.len() > 0 {
@@ -784,11 +784,11 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
     }
 
     fn print_closure_expr(&mut self, expr: &ClosureExpr<'tcx>, depth_lvl: usize) {
-        let ClosureExpr { closure_id, substs, upvars, movability, fake_reads } = expr;
+        let ClosureExpr { closure_id, args, upvars, movability, fake_reads } = expr;
 
         print_indented!(self, "ClosureExpr {", depth_lvl);
         print_indented!(self, format!("closure_id: {:?}", closure_id), depth_lvl + 1);
-        print_indented!(self, format!("substs: {:?}", substs), depth_lvl + 1);
+        print_indented!(self, format!("args: {:?}", args), depth_lvl + 1);
 
         if upvars.len() > 0 {
             print_indented!(self, "upvars: [", depth_lvl + 1);
diff --git a/compiler/rustc_mir_build/src/thir/util.rs b/compiler/rustc_mir_build/src/thir/util.rs
index c58ed1ac0..9106b4d33 100644
--- a/compiler/rustc_mir_build/src/thir/util.rs
+++ b/compiler/rustc_mir_build/src/thir/util.rs
@@ -9,7 +9,7 @@ pub(crate) trait UserAnnotatedTyHelpers<'tcx> {
     /// Looks up the type associated with this hir-id and applies the
     /// user-given substitutions; the hir-id must map to a suitable
     /// type.
-    fn user_substs_applied_to_ty_of_hir_id(
+    fn user_args_applied_to_ty_of_hir_id(
         &self,
         hir_id: hir::HirId,
     ) -> Option<CanonicalUserType<'tcx>> {