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-rw-r--r--compiler/rustc_borrowck/src/borrowck_errors.rs4
-rw-r--r--compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs8
-rw-r--r--compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs20
-rw-r--r--compiler/rustc_borrowck/src/lib.rs4
-rw-r--r--compiler/rustc_borrowck/src/region_infer/mod.rs4
-rw-r--r--compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs76
-rw-r--r--compiler/rustc_borrowck/src/root_cx.rs22
-rw-r--r--compiler/rustc_hir_analysis/src/check/check.rs4
-rw-r--r--compiler/rustc_hir_analysis/src/collect.rs4
-rw-r--r--compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs12
-rw-r--r--compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs1
-rw-r--r--compiler/rustc_hir_typeck/src/opaque_types.rs19
-rw-r--r--compiler/rustc_hir_typeck/src/writeback.rs28
-rw-r--r--compiler/rustc_middle/src/arena.rs2
-rw-r--r--compiler/rustc_middle/src/mir/query.rs7
-rw-r--r--compiler/rustc_middle/src/query/mod.rs2
-rw-r--r--compiler/rustc_middle/src/ty/typeck_results.rs4
-rw-r--r--compiler/rustc_mir_transform/src/abort_unwinding_calls.rs37
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs5
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/effect_goals.rs21
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs19
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs135
-rw-r--r--compiler/rustc_next_trait_solver/src/solve/trait_goals.rs46
-rw-r--r--compiler/rustc_pattern_analysis/src/rustc.rs4
-rw-r--r--compiler/rustc_span/src/symbol.rs1
-rw-r--r--compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs45
-rw-r--r--compiler/rustc_trait_selection/src/traits/select/mod.rs2
-rw-r--r--compiler/rustc_type_ir/src/infer_ctxt.rs2
-rw-r--r--library/alloc/src/rc.rs4
-rw-r--r--library/alloc/src/sync.rs16
-rw-r--r--library/proc_macro/src/bridge/client.rs19
-rw-r--r--library/proc_macro/src/bridge/closure.rs4
-rw-r--r--library/proc_macro/src/bridge/mod.rs28
-rw-r--r--library/proc_macro/src/bridge/server.rs16
-rw-r--r--library/proc_macro/src/lib.rs1
-rw-r--r--library/std/src/path.rs187
-rw-r--r--library/std/tests/path.rs38
-rw-r--r--src/bootstrap/src/core/build_steps/doc.rs21
-rw-r--r--src/bootstrap/src/core/builder/cargo.rs12
-rw-r--r--src/bootstrap/src/core/builder/tests.rs18
-rw-r--r--src/ci/github-actions/jobs.yml14
-rw-r--r--src/librustdoc/passes/mod.rs4
-rw-r--r--tests/codegen-llvm/unwind-abis/c-unwind-abi-panic-abort.rs9
-rw-r--r--tests/codegen-llvm/unwind-and-panic-abort.rs9
-rw-r--r--tests/codegen-llvm/wasm_exceptions.rs57
-rw-r--r--tests/rustdoc-ui/issues/issue-91713.stdout4
-rw-r--r--tests/rustdoc/doc-auto-cfg-public-in-private.rs16
-rw-r--r--tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs14
-rw-r--r--tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr63
-rw-r--r--tests/ui/borrowck/fn-item-check-type-params.stderr12
-rw-r--r--tests/ui/borrowck/implementation-not-general-enough-ice-133252.stderr6
-rw-r--r--tests/ui/borrowck/issue-17545.stderr3
-rw-r--r--tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.rs20
-rw-r--r--tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.stderr19
-rw-r--r--tests/ui/const-generics/generic_arg_infer/in-signature.stderr36
-rw-r--r--tests/ui/error-codes/E0121.stderr11
-rw-r--r--tests/ui/errors/span-format_args-issue-140578.rs32
-rw-r--r--tests/ui/errors/span-format_args-issue-140578.stderr43
-rw-r--r--tests/ui/fn/issue-80179.stderr21
-rw-r--r--tests/ui/fn/suggest-return-closure.stderr30
-rw-r--r--tests/ui/fn/suggest-return-future.stderr22
-rw-r--r--tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr5
-rw-r--r--tests/ui/impl-trait/precise-capturing/migration-note.rs2
-rw-r--r--tests/ui/impl-trait/precise-capturing/migration-note.stderr54
-rw-r--r--tests/ui/inference/need_type_info/issue-107745-avoid-expr-from-macro-expansion.stderr6
-rw-r--r--tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr6
-rw-r--r--tests/ui/nll/closure-requirements/propagate-multiple-requirements.stderr6
-rw-r--r--tests/ui/nll/local-outlives-static-via-hrtb.stderr10
-rw-r--r--tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.nll.stderr5
-rw-r--r--tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.polonius.stderr5
-rw-r--r--tests/ui/regions/multiple-sources-for-outlives-requirement.rs11
-rw-r--r--tests/ui/regions/multiple-sources-for-outlives-requirement.stderr20
-rw-r--r--tests/ui/regions/regions-infer-proc-static-upvar.stderr6
-rw-r--r--tests/ui/regions/regions-pattern-typing-issue-19552.stderr6
-rw-r--r--tests/ui/return/infer-return-ty-for-fn-sig-issue-125488.stderr44
-rw-r--r--tests/ui/static/static-lifetime-bound.stderr6
-rw-r--r--tests/ui/static/static-region-bound.stderr6
-rw-r--r--tests/ui/suggestions/return-cycle-2.stderr11
-rw-r--r--tests/ui/suggestions/return-cycle.stderr11
-rw-r--r--tests/ui/suggestions/suggest-fn-ptr-for-fn-item-in-fn-ret.stderr11
-rw-r--r--tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-1.rs25
-rw-r--r--tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-2.rs14
-rw-r--r--tests/ui/type-alias-impl-trait/issue-77179.stderr11
-rw-r--r--tests/ui/typeck/issue-80779.stderr22
-rw-r--r--tests/ui/typeck/issue-98260.stderr11
-rw-r--r--tests/ui/typeck/typeck_type_placeholder_item.stderr141
-rw-r--r--tests/ui/typeck/typeck_type_placeholder_item_help.stderr11
-rw-r--r--tests/ui/variance/leaking-unnameables.stderr11
-rw-r--r--tests/ui/wf/wf-in-where-clause-static.current.stderr6
-rw-r--r--tests/ui/wf/wf-in-where-clause-static.next.stderr6
90 files changed, 1274 insertions, 562 deletions
diff --git a/compiler/rustc_borrowck/src/borrowck_errors.rs b/compiler/rustc_borrowck/src/borrowck_errors.rs
index c9be5575da5..7c9011505d6 100644
--- a/compiler/rustc_borrowck/src/borrowck_errors.rs
+++ b/compiler/rustc_borrowck/src/borrowck_errors.rs
@@ -426,7 +426,7 @@ impl<'infcx, 'tcx> crate::MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     }
 
     pub(crate) fn path_does_not_live_long_enough(&self, span: Span, path: &str) -> Diag<'infcx> {
-        struct_span_code_err!(self.dcx(), span, E0597, "{} does not live long enough", path,)
+        struct_span_code_err!(self.dcx(), span, E0597, "{} does not live long enough", path)
     }
 
     pub(crate) fn cannot_return_reference_to_local(
@@ -480,7 +480,7 @@ impl<'infcx, 'tcx> crate::MirBorrowckCtxt<'_, 'infcx, 'tcx> {
     }
 
     pub(crate) fn temporary_value_borrowed_for_too_long(&self, span: Span) -> Diag<'infcx> {
-        struct_span_code_err!(self.dcx(), span, E0716, "temporary value dropped while borrowed",)
+        struct_span_code_err!(self.dcx(), span, E0716, "temporary value dropped while borrowed")
     }
 }
 
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 7e20a5133e0..efb622e2155 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -2992,6 +2992,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         self.buffer_error(err);
     }
 
+    #[tracing::instrument(level = "debug", skip(self, explanation))]
     fn report_local_value_does_not_live_long_enough(
         &self,
         location: Location,
@@ -3001,13 +3002,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         borrow_spans: UseSpans<'tcx>,
         explanation: BorrowExplanation<'tcx>,
     ) -> Diag<'infcx> {
-        debug!(
-            "report_local_value_does_not_live_long_enough(\
-             {:?}, {:?}, {:?}, {:?}, {:?}\
-             )",
-            location, name, borrow, drop_span, borrow_spans
-        );
-
         let borrow_span = borrow_spans.var_or_use_path_span();
         if let BorrowExplanation::MustBeValidFor {
             category,
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index 7ca07bb9b43..638d89f5bcb 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -416,6 +416,26 @@ impl<'tcx> BorrowExplanation<'tcx> {
                 {
                     self.add_object_lifetime_default_note(tcx, err, unsize_ty);
                 }
+
+                let mut preds = path
+                    .iter()
+                    .filter_map(|constraint| match constraint.category {
+                        ConstraintCategory::Predicate(pred) if !pred.is_dummy() => Some(pred),
+                        _ => None,
+                    })
+                    .collect::<Vec<Span>>();
+                preds.sort();
+                preds.dedup();
+                if !preds.is_empty() {
+                    let s = if preds.len() == 1 { "" } else { "s" };
+                    err.span_note(
+                        preds,
+                        format!(
+                            "requirement{s} that the value outlives `{region_name}` introduced here"
+                        ),
+                    );
+                }
+
                 self.add_lifetime_bound_suggestion_to_diagnostic(err, &category, span, region_name);
             }
             _ => {}
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 4c380ddcf70..268cb47fd12 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -119,7 +119,7 @@ pub fn provide(providers: &mut Providers) {
 fn mir_borrowck(
     tcx: TyCtxt<'_>,
     def: LocalDefId,
-) -> Result<&ConcreteOpaqueTypes<'_>, ErrorGuaranteed> {
+) -> Result<&DefinitionSiteHiddenTypes<'_>, ErrorGuaranteed> {
     assert!(!tcx.is_typeck_child(def.to_def_id()));
     let (input_body, _) = tcx.mir_promoted(def);
     debug!("run query mir_borrowck: {}", tcx.def_path_str(def));
@@ -130,7 +130,7 @@ fn mir_borrowck(
         Err(guar)
     } else if input_body.should_skip() {
         debug!("Skipping borrowck because of injected body");
-        let opaque_types = ConcreteOpaqueTypes(Default::default());
+        let opaque_types = DefinitionSiteHiddenTypes(Default::default());
         Ok(tcx.arena.alloc(opaque_types))
     } else {
         let mut root_cx = BorrowCheckRootCtxt::new(tcx, def, None);
diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index 0910e8ef4b3..e98c60e6338 100644
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -1382,10 +1382,10 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     /// The constraints we get from equating the hidden type of each use of an opaque
-    /// with its final concrete type may end up getting preferred over other, potentially
+    /// with its final hidden type may end up getting preferred over other, potentially
     /// longer constraint paths.
     ///
-    /// Given that we compute the final concrete type by relying on this existing constraint
+    /// Given that we compute the final hidden type by relying on this existing constraint
     /// path, this can easily end up hiding the actual reason for why we require these regions
     /// to be equal.
     ///
diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs
index 0af636aa734..8d89f3e0d87 100644
--- a/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types/mod.rs
@@ -8,7 +8,7 @@ use rustc_infer::infer::outlives::env::RegionBoundPairs;
 use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin, OpaqueTypeStorageEntries};
 use rustc_infer::traits::ObligationCause;
 use rustc_macros::extension;
-use rustc_middle::mir::{Body, ConcreteOpaqueTypes, ConstraintCategory};
+use rustc_middle::mir::{Body, ConstraintCategory, DefinitionSiteHiddenTypes};
 use rustc_middle::ty::{
     self, DefiningScopeKind, EarlyBinder, FallibleTypeFolder, GenericArg, GenericArgsRef,
     OpaqueHiddenType, OpaqueTypeKey, Region, RegionVid, Ty, TyCtxt, TypeFoldable,
@@ -129,9 +129,9 @@ fn nll_var_to_universal_region<'tcx>(
 /// Collect all defining uses of opaque types inside of this typeck root. This
 /// expects the hidden type to be mapped to the definition parameters of the opaque
 /// and errors if we end up with distinct hidden types.
-fn add_concrete_opaque_type<'tcx>(
+fn add_hidden_type<'tcx>(
     tcx: TyCtxt<'tcx>,
-    concrete_opaque_types: &mut ConcreteOpaqueTypes<'tcx>,
+    hidden_types: &mut DefinitionSiteHiddenTypes<'tcx>,
     def_id: LocalDefId,
     hidden_ty: OpaqueHiddenType<'tcx>,
 ) {
@@ -139,7 +139,7 @@ fn add_concrete_opaque_type<'tcx>(
     // back to the opaque type definition. E.g. we may have `OpaqueType<X, Y>` mapped to
     // `(X, Y)` and `OpaqueType<Y, X>` mapped to `(Y, X)`, and those are the same, but we
     // only know that once we convert the generic parameters to those of the opaque type.
-    if let Some(prev) = concrete_opaque_types.0.get_mut(&def_id) {
+    if let Some(prev) = hidden_types.0.get_mut(&def_id) {
         if prev.ty != hidden_ty.ty {
             let guar = hidden_ty.ty.error_reported().err().unwrap_or_else(|| {
                 let (Ok(e) | Err(e)) = prev.build_mismatch_error(&hidden_ty, tcx).map(|d| d.emit());
@@ -151,15 +151,15 @@ fn add_concrete_opaque_type<'tcx>(
         // FIXME(oli-obk): collect multiple spans for better diagnostics down the road.
         prev.span = prev.span.substitute_dummy(hidden_ty.span);
     } else {
-        concrete_opaque_types.0.insert(def_id, hidden_ty);
+        hidden_types.0.insert(def_id, hidden_ty);
     }
 }
 
-fn get_concrete_opaque_type<'tcx>(
-    concrete_opaque_types: &ConcreteOpaqueTypes<'tcx>,
+fn get_hidden_type<'tcx>(
+    hidden_types: &DefinitionSiteHiddenTypes<'tcx>,
     def_id: LocalDefId,
 ) -> Option<EarlyBinder<'tcx, OpaqueHiddenType<'tcx>>> {
-    concrete_opaque_types.0.get(&def_id).map(|ty| EarlyBinder::bind(*ty))
+    hidden_types.0.get(&def_id).map(|ty| EarlyBinder::bind(*ty))
 }
 
 #[derive(Debug)]
@@ -173,22 +173,22 @@ struct DefiningUse<'tcx> {
 }
 
 /// This computes the actual hidden types of the opaque types and maps them to their
-/// definition sites. Outside of registering the computed concrete types this function
+/// definition sites. Outside of registering the computed hidden types this function
 /// does not mutate the current borrowck state.
 ///
 /// While it may fail to infer the hidden type and return errors, we always apply
-/// the computed concrete hidden type to all opaque type uses to check whether they
+/// the computed hidden type to all opaque type uses to check whether they
 /// are correct. This is necessary to support non-defining uses of opaques in their
 /// defining scope.
 ///
 /// It also means that this whole function is not really soundness critical as we
 /// recheck all uses of the opaques regardless.
-pub(crate) fn compute_concrete_opaque_types<'tcx>(
+pub(crate) fn compute_definition_site_hidden_types<'tcx>(
     infcx: &BorrowckInferCtxt<'tcx>,
     universal_region_relations: &Frozen<UniversalRegionRelations<'tcx>>,
     constraints: &MirTypeckRegionConstraints<'tcx>,
     location_map: Rc<DenseLocationMap>,
-    concrete_opaque_types: &mut ConcreteOpaqueTypes<'tcx>,
+    hidden_types: &mut DefinitionSiteHiddenTypes<'tcx>,
     opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)],
 ) -> Vec<DeferredOpaqueTypeError<'tcx>> {
     let mut errors = Vec::new();
@@ -201,8 +201,7 @@ pub(crate) fn compute_concrete_opaque_types<'tcx>(
     // We start by checking each use of an opaque type during type check and
     // check whether the generic arguments of the opaque type are fully
     // universal, if so, it's a defining use.
-    let defining_uses =
-        collect_defining_uses(&mut rcx, concrete_opaque_types, opaque_types, &mut errors);
+    let defining_uses = collect_defining_uses(&mut rcx, hidden_types, opaque_types, &mut errors);
 
     // We now compute and apply member constraints for all regions in the hidden
     // types of each defining use. This mutates the region values of the `rcx` which
@@ -210,11 +209,11 @@ pub(crate) fn compute_concrete_opaque_types<'tcx>(
     apply_member_constraints(&mut rcx, &defining_uses);
 
     // After applying member constraints, we now check whether all member regions ended
-    // up equal to one of their choice regions and compute the actual concrete type of
+    // up equal to one of their choice regions and compute the actual hidden type of
     // the opaque type definition. This is stored in the `root_cx`.
-    compute_concrete_types_from_defining_uses(
+    compute_definition_site_hidden_types_from_defining_uses(
         &rcx,
-        concrete_opaque_types,
+        hidden_types,
         &defining_uses,
         &mut errors,
     );
@@ -224,7 +223,7 @@ pub(crate) fn compute_concrete_opaque_types<'tcx>(
 #[instrument(level = "debug", skip_all, ret)]
 fn collect_defining_uses<'tcx>(
     rcx: &mut RegionCtxt<'_, 'tcx>,
-    concrete_opaque_types: &mut ConcreteOpaqueTypes<'tcx>,
+    hidden_types: &mut DefinitionSiteHiddenTypes<'tcx>,
     opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)],
     errors: &mut Vec<DeferredOpaqueTypeError<'tcx>>,
 ) -> Vec<DefiningUse<'tcx>> {
@@ -244,9 +243,9 @@ fn collect_defining_uses<'tcx>(
             // with `TypingMode::Borrowck`.
             if infcx.tcx.use_typing_mode_borrowck() {
                 match err {
-                    NonDefiningUseReason::Tainted(guar) => add_concrete_opaque_type(
+                    NonDefiningUseReason::Tainted(guar) => add_hidden_type(
                         infcx.tcx,
-                        concrete_opaque_types,
+                        hidden_types,
                         opaque_type_key.def_id,
                         OpaqueHiddenType::new_error(infcx.tcx, guar),
                     ),
@@ -277,9 +276,9 @@ fn collect_defining_uses<'tcx>(
     defining_uses
 }
 
-fn compute_concrete_types_from_defining_uses<'tcx>(
+fn compute_definition_site_hidden_types_from_defining_uses<'tcx>(
     rcx: &RegionCtxt<'_, 'tcx>,
-    concrete_opaque_types: &mut ConcreteOpaqueTypes<'tcx>,
+    hidden_types: &mut DefinitionSiteHiddenTypes<'tcx>,
     defining_uses: &[DefiningUse<'tcx>],
     errors: &mut Vec<DeferredOpaqueTypeError<'tcx>>,
 ) {
@@ -358,9 +357,9 @@ fn compute_concrete_types_from_defining_uses<'tcx>(
                 },
             ));
         }
-        add_concrete_opaque_type(
+        add_hidden_type(
             tcx,
-            concrete_opaque_types,
+            hidden_types,
             opaque_type_key.def_id,
             OpaqueHiddenType { span: hidden_type.span, ty },
         );
@@ -489,20 +488,20 @@ impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for ToArgRegionsFolder<'_, 'tcx> {
 ///
 /// It does this by equating the hidden type of each use with the instantiated final
 /// hidden type of the opaque.
-pub(crate) fn apply_computed_concrete_opaque_types<'tcx>(
+pub(crate) fn apply_definition_site_hidden_types<'tcx>(
     infcx: &BorrowckInferCtxt<'tcx>,
     body: &Body<'tcx>,
     universal_regions: &UniversalRegions<'tcx>,
     region_bound_pairs: &RegionBoundPairs<'tcx>,
     known_type_outlives_obligations: &[ty::PolyTypeOutlivesPredicate<'tcx>],
     constraints: &mut MirTypeckRegionConstraints<'tcx>,
-    concrete_opaque_types: &mut ConcreteOpaqueTypes<'tcx>,
+    hidden_types: &mut DefinitionSiteHiddenTypes<'tcx>,
     opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)],
 ) -> Vec<DeferredOpaqueTypeError<'tcx>> {
     let tcx = infcx.tcx;
     let mut errors = Vec::new();
     for &(key, hidden_type) in opaque_types {
-        let Some(expected) = get_concrete_opaque_type(concrete_opaque_types, key.def_id) else {
+        let Some(expected) = get_hidden_type(hidden_types, key.def_id) else {
             if !tcx.use_typing_mode_borrowck() {
                 if let ty::Alias(ty::Opaque, alias_ty) = hidden_type.ty.kind()
                     && alias_ty.def_id == key.def_id.to_def_id()
@@ -521,12 +520,7 @@ pub(crate) fn apply_computed_concrete_opaque_types<'tcx>(
                 hidden_type.span,
                 "non-defining use in the defining scope with no defining uses",
             );
-            add_concrete_opaque_type(
-                tcx,
-                concrete_opaque_types,
-                key.def_id,
-                OpaqueHiddenType::new_error(tcx, guar),
-            );
+            add_hidden_type(tcx, hidden_types, key.def_id, OpaqueHiddenType::new_error(tcx, guar));
             continue;
         };
 
@@ -566,18 +560,13 @@ pub(crate) fn apply_computed_concrete_opaque_types<'tcx>(
                 "equating opaque types",
             ),
         ) {
-            add_concrete_opaque_type(
-                tcx,
-                concrete_opaque_types,
-                key.def_id,
-                OpaqueHiddenType::new_error(tcx, guar),
-            );
+            add_hidden_type(tcx, hidden_types, key.def_id, OpaqueHiddenType::new_error(tcx, guar));
         }
     }
     errors
 }
 
-/// In theory `apply_concrete_opaque_types` could introduce new uses of opaque types.
+/// In theory `apply_definition_site_hidden_types` could introduce new uses of opaque types.
 /// We do not check these new uses so this could be unsound.
 ///
 /// We detect any new uses and simply delay a bug if they occur. If this results in
@@ -682,13 +671,6 @@ impl<'tcx> InferCtxt<'tcx> {
     ///
     /// (*) C1 and C2 were introduced in the comments on
     /// `register_member_constraints`. Read that comment for more context.
-    ///
-    /// # Parameters
-    ///
-    /// - `def_id`, the `impl Trait` type
-    /// - `args`, the args used to instantiate this opaque type
-    /// - `instantiated_ty`, the inferred type C1 -- fully resolved, lifted version of
-    ///   `opaque_defn.concrete_ty`
     #[instrument(level = "debug", skip(self))]
     fn infer_opaque_definition_from_instantiation(
         &self,
diff --git a/compiler/rustc_borrowck/src/root_cx.rs b/compiler/rustc_borrowck/src/root_cx.rs
index cd4e9683f2d..21c11e12873 100644
--- a/compiler/rustc_borrowck/src/root_cx.rs
+++ b/compiler/rustc_borrowck/src/root_cx.rs
@@ -12,12 +12,12 @@ use smallvec::SmallVec;
 use crate::consumers::BorrowckConsumer;
 use crate::nll::compute_closure_requirements_modulo_opaques;
 use crate::region_infer::opaque_types::{
-    apply_computed_concrete_opaque_types, clone_and_resolve_opaque_types,
-    compute_concrete_opaque_types, detect_opaque_types_added_while_handling_opaque_types,
+    apply_definition_site_hidden_types, clone_and_resolve_opaque_types,
+    compute_definition_site_hidden_types, detect_opaque_types_added_while_handling_opaque_types,
 };
 use crate::type_check::{Locations, constraint_conversion};
 use crate::{
-    ClosureRegionRequirements, CollectRegionConstraintsResult, ConcreteOpaqueTypes,
+    ClosureRegionRequirements, CollectRegionConstraintsResult, DefinitionSiteHiddenTypes,
     PropagatedBorrowCheckResults, borrowck_check_region_constraints,
     borrowck_collect_region_constraints,
 };
@@ -27,7 +27,7 @@ use crate::{
 pub(super) struct BorrowCheckRootCtxt<'tcx> {
     pub tcx: TyCtxt<'tcx>,
     root_def_id: LocalDefId,
-    concrete_opaque_types: ConcreteOpaqueTypes<'tcx>,
+    hidden_types: DefinitionSiteHiddenTypes<'tcx>,
     /// The region constraints computed by [borrowck_collect_region_constraints]. This uses
     /// an [FxIndexMap] to guarantee that iterating over it visits nested bodies before
     /// their parents.
@@ -49,7 +49,7 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> {
         BorrowCheckRootCtxt {
             tcx,
             root_def_id,
-            concrete_opaque_types: Default::default(),
+            hidden_types: Default::default(),
             collect_region_constraints_results: Default::default(),
             propagated_borrowck_results: Default::default(),
             tainted_by_errors: None,
@@ -72,11 +72,11 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> {
         &self.propagated_borrowck_results[&nested_body_def_id].used_mut_upvars
     }
 
-    pub(super) fn finalize(self) -> Result<&'tcx ConcreteOpaqueTypes<'tcx>, ErrorGuaranteed> {
+    pub(super) fn finalize(self) -> Result<&'tcx DefinitionSiteHiddenTypes<'tcx>, ErrorGuaranteed> {
         if let Some(guar) = self.tainted_by_errors {
             Err(guar)
         } else {
-            Ok(self.tcx.arena.alloc(self.concrete_opaque_types))
+            Ok(self.tcx.arena.alloc(self.hidden_types))
         }
     }
 
@@ -88,12 +88,12 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> {
                 &input.universal_region_relations,
                 &mut input.constraints,
             );
-            input.deferred_opaque_type_errors = compute_concrete_opaque_types(
+            input.deferred_opaque_type_errors = compute_definition_site_hidden_types(
                 &input.infcx,
                 &input.universal_region_relations,
                 &input.constraints,
                 Rc::clone(&input.location_map),
-                &mut self.concrete_opaque_types,
+                &mut self.hidden_types,
                 &opaque_types,
             );
             per_body_info.push((num_entries, opaque_types));
@@ -103,14 +103,14 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> {
             self.collect_region_constraints_results.values_mut().zip(per_body_info)
         {
             if input.deferred_opaque_type_errors.is_empty() {
-                input.deferred_opaque_type_errors = apply_computed_concrete_opaque_types(
+                input.deferred_opaque_type_errors = apply_definition_site_hidden_types(
                     &input.infcx,
                     &input.body_owned,
                     &input.universal_region_relations.universal_regions,
                     &input.region_bound_pairs,
                     &input.known_type_outlives_obligations,
                     &mut input.constraints,
-                    &mut self.concrete_opaque_types,
+                    &mut self.hidden_types,
                     &opaque_types,
                 );
             }
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 886ebddc75c..e1e6860e430 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -219,7 +219,7 @@ fn check_opaque(tcx: TyCtxt<'_>, def_id: LocalDefId) {
 
     // HACK(jynelson): trying to infer the type of `impl trait` breaks documenting
     // `async-std` (and `pub async fn` in general).
-    // Since rustdoc doesn't care about the concrete type behind `impl Trait`, just don't look at it!
+    // Since rustdoc doesn't care about the hidden type behind `impl Trait`, just don't look at it!
     // See https://github.com/rust-lang/rust/issues/75100
     if tcx.sess.opts.actually_rustdoc {
         return;
@@ -252,7 +252,7 @@ pub(super) fn check_opaque_for_cycles<'tcx>(
     Ok(())
 }
 
-/// Check that the concrete type behind `impl Trait` actually implements `Trait`.
+/// Check that the hidden type behind `impl Trait` actually implements `Trait`.
 ///
 /// This is mostly checked at the places that specify the opaque type, but we
 /// check those cases in the `param_env` of that function, which may have
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index b72e743f95b..02baaec3713 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -1140,7 +1140,7 @@ fn recover_infer_ret_ty<'tcx>(
     // recursive function definition to leak out into the fn sig.
     let mut recovered_ret_ty = None;
     if let Some(suggestable_ret_ty) = ret_ty.make_suggestable(tcx, false, None) {
-        diag.span_suggestion(
+        diag.span_suggestion_verbose(
             infer_ret_ty.span,
             "replace with the correct return type",
             suggestable_ret_ty,
@@ -1152,7 +1152,7 @@ fn recover_infer_ret_ty<'tcx>(
         tcx.param_env(def_id),
         ret_ty,
     ) {
-        diag.span_suggestion(
+        diag.span_suggestion_verbose(
             infer_ret_ty.span,
             "replace with an appropriate return type",
             sugg,
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs b/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
index b6d898886ac..a02990fe4ab 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
@@ -177,7 +177,7 @@ impl<'tcx> TaitConstraintLocator<'tcx> {
                 let tables = tcx.typeck(item_def_id);
                 if let Some(guar) = tables.tainted_by_errors {
                     self.insert_found(ty::OpaqueHiddenType::new_error(tcx, guar));
-                } else if let Some(&hidden_type) = tables.concrete_opaque_types.get(&self.def_id) {
+                } else if let Some(&hidden_type) = tables.hidden_types.get(&self.def_id) {
                     self.insert_found(hidden_type);
                 } else {
                     self.non_defining_use_in_defining_scope(item_def_id);
@@ -185,8 +185,8 @@ impl<'tcx> TaitConstraintLocator<'tcx> {
             }
             DefiningScopeKind::MirBorrowck => match tcx.mir_borrowck(item_def_id) {
                 Err(guar) => self.insert_found(ty::OpaqueHiddenType::new_error(tcx, guar)),
-                Ok(concrete_opaque_types) => {
-                    if let Some(&hidden_type) = concrete_opaque_types.0.get(&self.def_id) {
+                Ok(hidden_types) => {
+                    if let Some(&hidden_type) = hidden_types.0.get(&self.def_id) {
                         debug!(?hidden_type, "found constraint");
                         self.insert_found(hidden_type);
                     } else if let Err(guar) = tcx
@@ -247,7 +247,7 @@ pub(super) fn find_opaque_ty_constraints_for_rpit<'tcx>(
             let tables = tcx.typeck(owner_def_id);
             if let Some(guar) = tables.tainted_by_errors {
                 Ty::new_error(tcx, guar)
-            } else if let Some(hidden_ty) = tables.concrete_opaque_types.get(&def_id) {
+            } else if let Some(hidden_ty) = tables.hidden_types.get(&def_id) {
                 hidden_ty.ty
             } else {
                 assert!(!tcx.next_trait_solver_globally());
@@ -261,8 +261,8 @@ pub(super) fn find_opaque_ty_constraints_for_rpit<'tcx>(
             }
         }
         DefiningScopeKind::MirBorrowck => match tcx.mir_borrowck(owner_def_id) {
-            Ok(concrete_opaque_types) => {
-                if let Some(hidden_ty) = concrete_opaque_types.0.get(&def_id) {
+            Ok(hidden_types) => {
+                if let Some(hidden_ty) = hidden_types.0.get(&def_id) {
                     hidden_ty.ty
                 } else {
                     let hir_ty = tcx.type_of_opaque_hir_typeck(def_id).instantiate_identity();
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs
index 0458fa1204e..0a41659ec66 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs
@@ -134,6 +134,7 @@ fn is_valid_cmse_inputs<'tcx>(
 
     // this type is only used for layout computation, which does not rely on regions
     let fn_sig = tcx.instantiate_bound_regions_with_erased(fn_sig);
+    let fn_sig = tcx.erase_and_anonymize_regions(fn_sig);
 
     for (index, ty) in fn_sig.inputs().iter().enumerate() {
         let layout = tcx.layout_of(ty::TypingEnv::fully_monomorphized().as_query_input(*ty))?;
diff --git a/compiler/rustc_hir_typeck/src/opaque_types.rs b/compiler/rustc_hir_typeck/src/opaque_types.rs
index 5cefa506b5a..4c1fe69405e 100644
--- a/compiler/rustc_hir_typeck/src/opaque_types.rs
+++ b/compiler/rustc_hir_typeck/src/opaque_types.rs
@@ -15,7 +15,7 @@ use crate::FnCtxt;
 
 impl<'tcx> FnCtxt<'_, 'tcx> {
     /// This takes all the opaque type uses during HIR typeck. It first computes
-    /// the concrete hidden type by iterating over all defining uses.
+    /// the hidden type by iterating over all defining uses.
     ///
     /// A use during HIR typeck is defining if all non-lifetime arguments are
     /// unique generic parameters and the hidden type does not reference any
@@ -35,8 +35,8 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         }
         debug!(?opaque_types);
 
-        self.compute_concrete_opaque_types(&opaque_types);
-        self.apply_computed_concrete_opaque_types(&opaque_types);
+        self.compute_definition_site_hidden_types(&opaque_types);
+        self.apply_definition_site_hidden_types(&opaque_types);
     }
 }
 
@@ -71,7 +71,7 @@ impl<'tcx> UsageKind<'tcx> {
 }
 
 impl<'tcx> FnCtxt<'_, 'tcx> {
-    fn compute_concrete_opaque_types(
+    fn compute_definition_site_hidden_types(
         &mut self,
         opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)],
     ) {
@@ -142,7 +142,7 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
 
             self.typeck_results
                 .borrow_mut()
-                .concrete_opaque_types
+                .hidden_types
                 .insert(def_id, OpaqueHiddenType::new_error(tcx, guar));
             self.set_tainted_by_errors(guar);
         }
@@ -161,7 +161,7 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         ) {
             match err {
                 NonDefiningUseReason::Tainted(guar) => {
-                    self.typeck_results.borrow_mut().concrete_opaque_types.insert(
+                    self.typeck_results.borrow_mut().hidden_types.insert(
                         opaque_type_key.def_id,
                         OpaqueHiddenType::new_error(self.tcx, guar),
                     );
@@ -197,20 +197,19 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         let prev = self
             .typeck_results
             .borrow_mut()
-            .concrete_opaque_types
+            .hidden_types
             .insert(opaque_type_key.def_id, hidden_type);
         assert!(prev.is_none());
         UsageKind::HasDefiningUse
     }
 
-    fn apply_computed_concrete_opaque_types(
+    fn apply_definition_site_hidden_types(
         &mut self,
         opaque_types: &[(OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>)],
     ) {
         let tcx = self.tcx;
         for &(key, hidden_type) in opaque_types {
-            let expected =
-                *self.typeck_results.borrow_mut().concrete_opaque_types.get(&key.def_id).unwrap();
+            let expected = *self.typeck_results.borrow_mut().hidden_types.get(&key.def_id).unwrap();
 
             let expected = EarlyBinder::bind(expected.ty).instantiate(tcx, key.args);
             self.demand_eqtype(hidden_type.span, expected, hidden_type.ty);
diff --git a/compiler/rustc_hir_typeck/src/writeback.rs b/compiler/rustc_hir_typeck/src/writeback.rs
index d01eeb9a4b6..697029e55f7 100644
--- a/compiler/rustc_hir_typeck/src/writeback.rs
+++ b/compiler/rustc_hir_typeck/src/writeback.rs
@@ -550,13 +550,12 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
     fn visit_opaque_types_next(&mut self) {
         let mut fcx_typeck_results = self.fcx.typeck_results.borrow_mut();
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
-        for hidden_ty in fcx_typeck_results.concrete_opaque_types.values() {
+        for hidden_ty in fcx_typeck_results.hidden_types.values() {
             assert!(!hidden_ty.has_infer());
         }
 
-        assert_eq!(self.typeck_results.concrete_opaque_types.len(), 0);
-        self.typeck_results.concrete_opaque_types =
-            mem::take(&mut fcx_typeck_results.concrete_opaque_types);
+        assert_eq!(self.typeck_results.hidden_types.len(), 0);
+        self.typeck_results.hidden_types = mem::take(&mut fcx_typeck_results.hidden_types);
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -588,7 +587,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                 hidden_type.span,
                 DefiningScopeKind::HirTypeck,
             ) {
-                self.typeck_results.concrete_opaque_types.insert(
+                self.typeck_results.hidden_types.insert(
                     opaque_type_key.def_id,
                     ty::OpaqueHiddenType::new_error(tcx, err.report(self.fcx)),
                 );
@@ -600,16 +599,11 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                 DefiningScopeKind::HirTypeck,
             );
 
-            if let Some(prev) = self
-                .typeck_results
-                .concrete_opaque_types
-                .insert(opaque_type_key.def_id, hidden_type)
+            if let Some(prev) =
+                self.typeck_results.hidden_types.insert(opaque_type_key.def_id, hidden_type)
             {
-                let entry = &mut self
-                    .typeck_results
-                    .concrete_opaque_types
-                    .get_mut(&opaque_type_key.def_id)
-                    .unwrap();
+                let entry =
+                    &mut self.typeck_results.hidden_types.get_mut(&opaque_type_key.def_id).unwrap();
                 if prev.ty != hidden_type.ty {
                     if let Some(guar) = self.typeck_results.tainted_by_errors {
                         entry.ty = Ty::new_error(tcx, guar);
@@ -628,7 +622,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
 
         let recursive_opaques: Vec<_> = self
             .typeck_results
-            .concrete_opaque_types
+            .hidden_types
             .iter()
             .filter(|&(&def_id, hidden_ty)| {
                 hidden_ty
@@ -636,7 +630,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                     .visit_with(&mut HasRecursiveOpaque {
                         def_id,
                         seen: Default::default(),
-                        opaques: &self.typeck_results.concrete_opaque_types,
+                        opaques: &self.typeck_results.hidden_types,
                         tcx,
                     })
                     .is_break()
@@ -651,7 +645,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                 .with_code(E0720)
                 .emit();
             self.typeck_results
-                .concrete_opaque_types
+                .hidden_types
                 .insert(def_id, OpaqueHiddenType { span, ty: Ty::new_error(tcx, guar) });
         }
     }
diff --git a/compiler/rustc_middle/src/arena.rs b/compiler/rustc_middle/src/arena.rs
index fa6a2db38ef..feaad5bb96e 100644
--- a/compiler/rustc_middle/src/arena.rs
+++ b/compiler/rustc_middle/src/arena.rs
@@ -27,7 +27,7 @@ macro_rules! arena_types {
                     rustc_middle::mir::Body<'tcx>
                 >,
             [decode] typeck_results: rustc_middle::ty::TypeckResults<'tcx>,
-            [decode] borrowck_result: rustc_middle::mir::ConcreteOpaqueTypes<'tcx>,
+            [decode] borrowck_result: rustc_middle::mir::DefinitionSiteHiddenTypes<'tcx>,
             [] resolver: rustc_data_structures::steal::Steal<(
                 rustc_middle::ty::ResolverAstLowering,
                 std::sync::Arc<rustc_ast::Crate>,
diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs
index a509c40c89c..2e6c9f207e2 100644
--- a/compiler/rustc_middle/src/mir/query.rs
+++ b/compiler/rustc_middle/src/mir/query.rs
@@ -84,11 +84,10 @@ impl Debug for CoroutineLayout<'_> {
     }
 }
 
-/// All the opaque types that are restricted to concrete types
-/// by this function. Unlike the value in `TypeckResults`, this has
-/// unerased regions.
+/// All the opaque types that have had their hidden type fully computed.
+/// Unlike the value in `TypeckResults`, this has unerased regions.
 #[derive(Default, Debug, TyEncodable, TyDecodable, HashStable)]
-pub struct ConcreteOpaqueTypes<'tcx>(pub FxIndexMap<LocalDefId, OpaqueHiddenType<'tcx>>);
+pub struct DefinitionSiteHiddenTypes<'tcx>(pub FxIndexMap<LocalDefId, OpaqueHiddenType<'tcx>>);
 
 /// The result of the `mir_const_qualif` query.
 ///
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 326df9239aa..895c8c0295a 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1244,7 +1244,7 @@ rustc_queries! {
 
     /// Borrow-checks the given typeck root, e.g. functions, const/static items,
     /// and its children, e.g. closures, inline consts.
-    query mir_borrowck(key: LocalDefId) -> Result<&'tcx mir::ConcreteOpaqueTypes<'tcx>, ErrorGuaranteed> {
+    query mir_borrowck(key: LocalDefId) -> Result<&'tcx mir::DefinitionSiteHiddenTypes<'tcx>, ErrorGuaranteed> {
         desc { |tcx| "borrow-checking `{}`", tcx.def_path_str(key) }
     }
 
diff --git a/compiler/rustc_middle/src/ty/typeck_results.rs b/compiler/rustc_middle/src/ty/typeck_results.rs
index 8dd80aab946..944bd9756a9 100644
--- a/compiler/rustc_middle/src/ty/typeck_results.rs
+++ b/compiler/rustc_middle/src/ty/typeck_results.rs
@@ -167,7 +167,7 @@ pub struct TypeckResults<'tcx> {
     /// We also store the type here, so that the compiler can use it as a hint
     /// for figuring out hidden types, even if they are only set in dead code
     /// (which doesn't show up in MIR).
-    pub concrete_opaque_types: FxIndexMap<LocalDefId, ty::OpaqueHiddenType<'tcx>>,
+    pub hidden_types: FxIndexMap<LocalDefId, ty::OpaqueHiddenType<'tcx>>,
 
     /// Tracks the minimum captures required for a closure;
     /// see `MinCaptureInformationMap` for more details.
@@ -250,7 +250,7 @@ impl<'tcx> TypeckResults<'tcx> {
             coercion_casts: Default::default(),
             used_trait_imports: Default::default(),
             tainted_by_errors: None,
-            concrete_opaque_types: Default::default(),
+            hidden_types: Default::default(),
             closure_min_captures: Default::default(),
             closure_fake_reads: Default::default(),
             rvalue_scopes: Default::default(),
diff --git a/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs b/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
index 5bd6fdcf485..35a21a2a834 100644
--- a/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
+++ b/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
@@ -3,6 +3,7 @@ use rustc_ast::InlineAsmOptions;
 use rustc_middle::mir::*;
 use rustc_middle::span_bug;
 use rustc_middle::ty::{self, TyCtxt, layout};
+use rustc_span::sym;
 use rustc_target::spec::PanicStrategy;
 
 /// A pass that runs which is targeted at ensuring that codegen guarantees about
@@ -33,6 +34,19 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
             return;
         }
 
+        // Represent whether this compilation target fundamentally doesn't
+        // support unwinding at all at an ABI level. If this the target has no
+        // support for unwinding then cleanup actions, for example, are all
+        // unnecessary and can be considered unreachable.
+        //
+        // Currently this is only true for wasm targets on panic=abort when the
+        // `exception-handling` target feature is disabled. In such a
+        // configuration it's illegal to emit exception-related instructions so
+        // it's not possible to unwind.
+        let target_supports_unwinding = !(tcx.sess.target.is_like_wasm
+            && tcx.sess.panic_strategy() == PanicStrategy::Abort
+            && !tcx.asm_target_features(def_id).contains(&sym::exception_handling));
+
         // Here we test for this function itself whether its ABI allows
         // unwinding or not.
         let body_ty = tcx.type_of(def_id).skip_binder();
@@ -54,12 +68,18 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
             let Some(terminator) = &mut block.terminator else { continue };
             let span = terminator.source_info.span;
 
-            // If we see an `UnwindResume` terminator inside a function that cannot unwind, we need
-            // to replace it with `UnwindTerminate`.
-            if let TerminatorKind::UnwindResume = &terminator.kind
-                && !body_can_unwind
-            {
-                terminator.kind = TerminatorKind::UnwindTerminate(UnwindTerminateReason::Abi);
+            // If we see an `UnwindResume` terminator inside a function then:
+            //
+            // * If the target doesn't support unwinding at all, then this is an
+            //   unreachable block.
+            // * If the body cannot unwind, we need to replace it with
+            //   `UnwindTerminate`.
+            if let TerminatorKind::UnwindResume = &terminator.kind {
+                if !target_supports_unwinding {
+                    terminator.kind = TerminatorKind::Unreachable;
+                } else if !body_can_unwind {
+                    terminator.kind = TerminatorKind::UnwindTerminate(UnwindTerminateReason::Abi);
+                }
             }
 
             if block.is_cleanup {
@@ -93,8 +113,9 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
                 _ => continue,
             };
 
-            if !call_can_unwind {
-                // If this function call can't unwind, then there's no need for it
+            if !call_can_unwind || !target_supports_unwinding {
+                // If this function call can't unwind, or if the target doesn't
+                // support unwinding at all, then there's no need for it
                 // to have a landing pad. This means that we can remove any cleanup
                 // registered for it (and turn it into `UnwindAction::Unreachable`).
                 let cleanup = block.terminator_mut().unwind_mut().unwrap();
diff --git a/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs b/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
index c40739d12e6..9b3dc1f691f 100644
--- a/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
@@ -664,7 +664,7 @@ fn coroutine_closure_to_ambiguous_coroutine<I: Interner>(
 pub(in crate::solve) fn extract_fn_def_from_const_callable<I: Interner>(
     cx: I,
     self_ty: I::Ty,
-) -> Result<(ty::Binder<I, (I::FnInputTys, I::Ty)>, I::FunctionId, I::GenericArgs), NoSolution> {
+) -> Result<(ty::Binder<I, (I::Ty, I::Ty)>, I::FunctionId, I::GenericArgs), NoSolution> {
     match self_ty.kind() {
         ty::FnDef(def_id, args) => {
             let sig = cx.fn_sig(def_id);
@@ -673,7 +673,8 @@ pub(in crate::solve) fn extract_fn_def_from_const_callable<I: Interner>(
                 && cx.fn_is_const(def_id)
             {
                 Ok((
-                    sig.instantiate(cx, args).map_bound(|sig| (sig.inputs(), sig.output())),
+                    sig.instantiate(cx, args)
+                        .map_bound(|sig| (Ty::new_tup(cx, sig.inputs().as_slice()), sig.output())),
                     def_id,
                     args,
                 ))
diff --git a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
index cb72c1cd92b..65a5edf6b72 100644
--- a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
@@ -234,12 +234,12 @@ where
         let self_ty = goal.predicate.self_ty();
         let (inputs_and_output, def_id, args) =
             structural_traits::extract_fn_def_from_const_callable(cx, self_ty)?;
+        let (inputs, output) = ecx.instantiate_binder_with_infer(inputs_and_output);
 
         // A built-in `Fn` impl only holds if the output is sized.
         // (FIXME: technically we only need to check this if the type is a fn ptr...)
-        let output_is_sized_pred = inputs_and_output.map_bound(|(_, output)| {
-            ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output])
-        });
+        let output_is_sized_pred =
+            ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output]);
         let requirements = cx
             .const_conditions(def_id.into())
             .iter_instantiated(cx, args)
@@ -251,15 +251,12 @@ where
             })
             .chain([(GoalSource::ImplWhereBound, goal.with(cx, output_is_sized_pred))]);
 
-        let pred = inputs_and_output
-            .map_bound(|(inputs, _)| {
-                ty::TraitRef::new(
-                    cx,
-                    goal.predicate.def_id(),
-                    [goal.predicate.self_ty(), Ty::new_tup(cx, inputs.as_slice())],
-                )
-            })
-            .to_host_effect_clause(cx, goal.predicate.constness);
+        let pred = ty::Binder::dummy(ty::TraitRef::new(
+            cx,
+            goal.predicate.def_id(),
+            [goal.predicate.self_ty(), inputs],
+        ))
+        .to_host_effect_clause(cx, goal.predicate.constness);
 
         Self::probe_and_consider_implied_clause(
             ecx,
diff --git a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
index 85110530ae9..f25003bbfe9 100644
--- a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
@@ -633,28 +633,19 @@ where
     // the certainty of all the goals.
     #[instrument(level = "trace", skip(self))]
     pub(super) fn try_evaluate_added_goals(&mut self) -> Result<Certainty, NoSolution> {
-        let mut response = Ok(Certainty::overflow(false));
         for _ in 0..FIXPOINT_STEP_LIMIT {
-            // FIXME: This match is a bit ugly, it might be nice to change the inspect
-            // stuff to use a closure instead. which should hopefully simplify this a bit.
             match self.evaluate_added_goals_step() {
-                Ok(Some(cert)) => {
-                    response = Ok(cert);
-                    break;
-                }
                 Ok(None) => {}
+                Ok(Some(cert)) => return Ok(cert),
                 Err(NoSolution) => {
-                    response = Err(NoSolution);
-                    break;
+                    self.tainted = Err(NoSolution);
+                    return Err(NoSolution);
                 }
             }
         }
 
-        if response.is_err() {
-            self.tainted = Err(NoSolution);
-        }
-
-        response
+        debug!("try_evaluate_added_goals: encountered overflow");
+        Ok(Certainty::overflow(false))
     }
 
     /// Iterate over all added goals: returning `Ok(Some(_))` in case we can stop rerunning.
diff --git a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
index 653c59c5d42..0674b3d42ab 100644
--- a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
@@ -451,23 +451,22 @@ where
                     return ecx.forced_ambiguity(MaybeCause::Ambiguity);
                 }
             };
+        let (inputs, output) = ecx.instantiate_binder_with_infer(tupled_inputs_and_output);
 
         // A built-in `Fn` impl only holds if the output is sized.
         // (FIXME: technically we only need to check this if the type is a fn ptr...)
-        let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| {
-            ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output])
-        });
+        let output_is_sized_pred =
+            ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output]);
 
-        let pred = tupled_inputs_and_output
-            .map_bound(|(inputs, output)| ty::ProjectionPredicate {
-                projection_term: ty::AliasTerm::new(
-                    cx,
-                    goal.predicate.def_id(),
-                    [goal.predicate.self_ty(), inputs],
-                ),
-                term: output.into(),
-            })
-            .upcast(cx);
+        let pred = ty::ProjectionPredicate {
+            projection_term: ty::AliasTerm::new(
+                cx,
+                goal.predicate.def_id(),
+                [goal.predicate.self_ty(), inputs],
+            ),
+            term: output.into(),
+        }
+        .upcast(cx);
 
         Self::probe_and_consider_implied_clause(
             ecx,
@@ -497,76 +496,56 @@ where
                 goal_kind,
                 env_region,
             )?;
+        let AsyncCallableRelevantTypes {
+            tupled_inputs_ty,
+            output_coroutine_ty,
+            coroutine_return_ty,
+        } = ecx.instantiate_binder_with_infer(tupled_inputs_and_output_and_coroutine);
 
         // A built-in `AsyncFn` impl only holds if the output is sized.
         // (FIXME: technically we only need to check this if the type is a fn ptr...)
-        let output_is_sized_pred = tupled_inputs_and_output_and_coroutine.map_bound(
-            |AsyncCallableRelevantTypes { output_coroutine_ty: output_ty, .. }| {
-                ty::TraitRef::new(
-                    cx,
-                    cx.require_trait_lang_item(SolverTraitLangItem::Sized),
-                    [output_ty],
-                )
-            },
+        let output_is_sized_pred = ty::TraitRef::new(
+            cx,
+            cx.require_trait_lang_item(SolverTraitLangItem::Sized),
+            [output_coroutine_ty],
         );
 
-        let pred = tupled_inputs_and_output_and_coroutine
-            .map_bound(
-                |AsyncCallableRelevantTypes {
-                     tupled_inputs_ty,
-                     output_coroutine_ty,
-                     coroutine_return_ty,
-                 }| {
-                    let (projection_term, term) = if cx
-                        .is_lang_item(goal.predicate.def_id(), SolverLangItem::CallOnceFuture)
-                    {
-                        (
-                            ty::AliasTerm::new(
-                                cx,
-                                goal.predicate.def_id(),
-                                [goal.predicate.self_ty(), tupled_inputs_ty],
-                            ),
-                            output_coroutine_ty.into(),
-                        )
-                    } else if cx
-                        .is_lang_item(goal.predicate.def_id(), SolverLangItem::CallRefFuture)
-                    {
-                        (
-                            ty::AliasTerm::new(
-                                cx,
-                                goal.predicate.def_id(),
-                                [
-                                    I::GenericArg::from(goal.predicate.self_ty()),
-                                    tupled_inputs_ty.into(),
-                                    env_region.into(),
-                                ],
-                            ),
-                            output_coroutine_ty.into(),
-                        )
-                    } else if cx
-                        .is_lang_item(goal.predicate.def_id(), SolverLangItem::AsyncFnOnceOutput)
-                    {
-                        (
-                            ty::AliasTerm::new(
-                                cx,
-                                goal.predicate.def_id(),
-                                [
-                                    I::GenericArg::from(goal.predicate.self_ty()),
-                                    tupled_inputs_ty.into(),
-                                ],
-                            ),
-                            coroutine_return_ty.into(),
-                        )
-                    } else {
-                        panic!(
-                            "no such associated type in `AsyncFn*`: {:?}",
-                            goal.predicate.def_id()
-                        )
-                    };
-                    ty::ProjectionPredicate { projection_term, term }
-                },
-            )
-            .upcast(cx);
+        let (projection_term, term) =
+            if cx.is_lang_item(goal.predicate.def_id(), SolverLangItem::CallOnceFuture) {
+                (
+                    ty::AliasTerm::new(
+                        cx,
+                        goal.predicate.def_id(),
+                        [goal.predicate.self_ty(), tupled_inputs_ty],
+                    ),
+                    output_coroutine_ty.into(),
+                )
+            } else if cx.is_lang_item(goal.predicate.def_id(), SolverLangItem::CallRefFuture) {
+                (
+                    ty::AliasTerm::new(
+                        cx,
+                        goal.predicate.def_id(),
+                        [
+                            I::GenericArg::from(goal.predicate.self_ty()),
+                            tupled_inputs_ty.into(),
+                            env_region.into(),
+                        ],
+                    ),
+                    output_coroutine_ty.into(),
+                )
+            } else if cx.is_lang_item(goal.predicate.def_id(), SolverLangItem::AsyncFnOnceOutput) {
+                (
+                    ty::AliasTerm::new(
+                        cx,
+                        goal.predicate.def_id(),
+                        [goal.predicate.self_ty(), tupled_inputs_ty],
+                    ),
+                    coroutine_return_ty.into(),
+                )
+            } else {
+                panic!("no such associated type in `AsyncFn*`: {:?}", goal.predicate.def_id())
+            };
+        let pred = ty::ProjectionPredicate { projection_term, term }.upcast(cx);
 
         Self::probe_and_consider_implied_clause(
             ecx,
diff --git a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
index 3974114e9b4..e790ecd595b 100644
--- a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
@@ -369,18 +369,16 @@ where
                     return ecx.forced_ambiguity(MaybeCause::Ambiguity);
                 }
             };
+        let (inputs, output) = ecx.instantiate_binder_with_infer(tupled_inputs_and_output);
 
         // A built-in `Fn` impl only holds if the output is sized.
         // (FIXME: technically we only need to check this if the type is a fn ptr...)
-        let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| {
-            ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output])
-        });
+        let output_is_sized_pred =
+            ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output]);
 
-        let pred = tupled_inputs_and_output
-            .map_bound(|(inputs, _)| {
-                ty::TraitRef::new(cx, goal.predicate.def_id(), [goal.predicate.self_ty(), inputs])
-            })
-            .upcast(cx);
+        let pred =
+            ty::TraitRef::new(cx, goal.predicate.def_id(), [goal.predicate.self_ty(), inputs])
+                .upcast(cx);
         Self::probe_and_consider_implied_clause(
             ecx,
             CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
@@ -408,28 +406,26 @@ where
                 // This region doesn't matter because we're throwing away the coroutine type
                 Region::new_static(cx),
             )?;
+        let AsyncCallableRelevantTypes {
+            tupled_inputs_ty,
+            output_coroutine_ty,
+            coroutine_return_ty: _,
+        } = ecx.instantiate_binder_with_infer(tupled_inputs_and_output_and_coroutine);
 
         // A built-in `AsyncFn` impl only holds if the output is sized.
         // (FIXME: technically we only need to check this if the type is a fn ptr...)
-        let output_is_sized_pred = tupled_inputs_and_output_and_coroutine.map_bound(
-            |AsyncCallableRelevantTypes { output_coroutine_ty, .. }| {
-                ty::TraitRef::new(
-                    cx,
-                    cx.require_trait_lang_item(SolverTraitLangItem::Sized),
-                    [output_coroutine_ty],
-                )
-            },
+        let output_is_sized_pred = ty::TraitRef::new(
+            cx,
+            cx.require_trait_lang_item(SolverTraitLangItem::Sized),
+            [output_coroutine_ty],
         );
 
-        let pred = tupled_inputs_and_output_and_coroutine
-            .map_bound(|AsyncCallableRelevantTypes { tupled_inputs_ty, .. }| {
-                ty::TraitRef::new(
-                    cx,
-                    goal.predicate.def_id(),
-                    [goal.predicate.self_ty(), tupled_inputs_ty],
-                )
-            })
-            .upcast(cx);
+        let pred = ty::TraitRef::new(
+            cx,
+            goal.predicate.def_id(),
+            [goal.predicate.self_ty(), tupled_inputs_ty],
+        )
+        .upcast(cx);
         Self::probe_and_consider_implied_clause(
             ecx,
             CandidateSource::BuiltinImpl(BuiltinImplSource::Misc),
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs
index d9f8085083e..0652461e975 100644
--- a/compiler/rustc_pattern_analysis/src/rustc.rs
+++ b/compiler/rustc_pattern_analysis/src/rustc.rs
@@ -120,7 +120,7 @@ impl<'p, 'tcx: 'p> fmt::Debug for RustcPatCtxt<'p, 'tcx> {
 impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
     /// Type inference occasionally gives us opaque types in places where corresponding patterns
     /// have more specific types. To avoid inconsistencies as well as detect opaque uninhabited
-    /// types, we use the corresponding concrete type if possible.
+    /// types, we use the corresponding hidden type if possible.
     // FIXME(#132279): This will be unnecessary once we have a TypingMode which supports revealing
     // opaque types defined in a body.
     #[inline]
@@ -146,7 +146,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
     /// know it.
     fn reveal_opaque_key(&self, key: OpaqueTypeKey<'tcx>) -> Option<Ty<'tcx>> {
         self.typeck_results
-            .concrete_opaque_types
+            .hidden_types
             .get(&key.def_id)
             .map(|x| ty::EarlyBinder::bind(x.ty).instantiate(self.tcx, key.args))
     }
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 63b0de377c9..b34a64108e3 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -940,6 +940,7 @@ symbols! {
         ermsb_target_feature,
         exact_div,
         except,
+        exception_handling: "exception-handling",
         exchange_malloc,
         exclusive_range_pattern,
         exhaustive_integer_patterns,
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
index b3d1b8e3888..9052031ce4f 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs
@@ -21,7 +21,7 @@ use rustc_infer::traits::{
 };
 use rustc_middle::ty::print::{PrintTraitRefExt as _, with_no_trimmed_paths};
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_span::{ErrorGuaranteed, ExpnKind, Span};
+use rustc_span::{DesugaringKind, ErrorGuaranteed, ExpnKind, Span};
 use tracing::{info, instrument};
 
 pub use self::overflow::*;
@@ -154,9 +154,20 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             })
             .collect();
 
-        // Ensure `T: Sized`, `T: MetaSized`, `T: PointeeSized` and `T: WF` obligations come last.
+        // Ensure `T: Sized`, `T: MetaSized`, `T: PointeeSized` and `T: WF` obligations come last,
+        // and `Subtype` obligations from `FormatLiteral` desugarings come first.
         // This lets us display diagnostics with more relevant type information and hide redundant
         // E0282 errors.
+        #[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+        enum ErrorSortKey {
+            SubtypeFormat(usize, usize),
+            OtherKind,
+            SizedTrait,
+            MetaSizedTrait,
+            PointeeSizedTrait,
+            Coerce,
+            WellFormed,
+        }
         errors.sort_by_key(|e| {
             let maybe_sizedness_did = match e.obligation.predicate.kind().skip_binder() {
                 ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) => Some(pred.def_id()),
@@ -165,12 +176,30 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             };
 
             match e.obligation.predicate.kind().skip_binder() {
-                _ if maybe_sizedness_did == self.tcx.lang_items().sized_trait() => 1,
-                _ if maybe_sizedness_did == self.tcx.lang_items().meta_sized_trait() => 2,
-                _ if maybe_sizedness_did == self.tcx.lang_items().pointee_sized_trait() => 3,
-                ty::PredicateKind::Coerce(_) => 4,
-                ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => 5,
-                _ => 0,
+                ty::PredicateKind::Subtype(_)
+                    if matches!(
+                        e.obligation.cause.span.desugaring_kind(),
+                        Some(DesugaringKind::FormatLiteral { .. })
+                    ) =>
+                {
+                    let (_, row, col, ..) =
+                        self.tcx.sess.source_map().span_to_location_info(e.obligation.cause.span);
+                    ErrorSortKey::SubtypeFormat(row, col)
+                }
+                _ if maybe_sizedness_did == self.tcx.lang_items().sized_trait() => {
+                    ErrorSortKey::SizedTrait
+                }
+                _ if maybe_sizedness_did == self.tcx.lang_items().meta_sized_trait() => {
+                    ErrorSortKey::MetaSizedTrait
+                }
+                _ if maybe_sizedness_did == self.tcx.lang_items().pointee_sized_trait() => {
+                    ErrorSortKey::PointeeSizedTrait
+                }
+                ty::PredicateKind::Coerce(_) => ErrorSortKey::Coerce,
+                ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_)) => {
+                    ErrorSortKey::WellFormed
+                }
+                _ => ErrorSortKey::OtherKind,
             }
         });
 
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 1dd31990ab7..fb4f28412d4 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -2359,7 +2359,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                 if self.infcx.can_define_opaque_ty(def_id) {
                     unreachable!()
                 } else {
-                    // We can resolve the `impl Trait` to its concrete type,
+                    // We can resolve the opaque type to its hidden type,
                     // which enforces a DAG between the functions requiring
                     // the auto trait bounds in question.
                     match self.tcx().type_of_opaque(def_id) {
diff --git a/compiler/rustc_type_ir/src/infer_ctxt.rs b/compiler/rustc_type_ir/src/infer_ctxt.rs
index f743b84bce6..feafcee7bad 100644
--- a/compiler/rustc_type_ir/src/infer_ctxt.rs
+++ b/compiler/rustc_type_ir/src/infer_ctxt.rs
@@ -80,7 +80,7 @@ pub enum TypingMode<I: Interner> {
     /// the old solver as well.
     PostBorrowckAnalysis { defined_opaque_types: I::LocalDefIds },
     /// After analysis, mostly during codegen and MIR optimizations, we're able to
-    /// reveal all opaque types. As the concrete type should *never* be observable
+    /// reveal all opaque types. As the hidden type should *never* be observable
     /// directly by the user, this should not be used by checks which may expose
     /// such details to the user.
     ///
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 627e5c7f976..023238a00db 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -277,7 +277,9 @@ use crate::vec::Vec;
 // This is repr(C) to future-proof against possible field-reordering, which
 // would interfere with otherwise safe [into|from]_raw() of transmutable
 // inner types.
-#[repr(C)]
+// repr(align(2)) (forcing alignment to at least 2) is required because usize
+// has 1-byte alignment on AVR.
+#[repr(C, align(2))]
 struct RcInner<T: ?Sized> {
     strong: Cell<usize>,
     weak: Cell<usize>,
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 3a8695d34a8..6432bdfbbed 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -341,7 +341,7 @@ pub struct Weak<
     // but it is not necessarily a valid pointer.
     // `Weak::new` sets this to `usize::MAX` so that it doesn’t need
     // to allocate space on the heap. That's not a value a real pointer
-    // will ever have because RcInner has alignment at least 2.
+    // will ever have because ArcInner has alignment at least 2.
     ptr: NonNull<ArcInner<T>>,
     alloc: A,
 }
@@ -366,7 +366,9 @@ impl<T: ?Sized, A: Allocator> fmt::Debug for Weak<T, A> {
 // This is repr(C) to future-proof against possible field-reordering, which
 // would interfere with otherwise safe [into|from]_raw() of transmutable
 // inner types.
-#[repr(C)]
+// Unlike RcInner, repr(align(2)) is not strictly required because atomic types
+// have the alignment same as its size, but we use it for consistency and clarity.
+#[repr(C, align(2))]
 struct ArcInner<T: ?Sized> {
     strong: Atomic<usize>,
 
@@ -1613,9 +1615,9 @@ impl<T: ?Sized, A: Allocator> Arc<T, A> {
     pub fn as_ptr(this: &Self) -> *const T {
         let ptr: *mut ArcInner<T> = NonNull::as_ptr(this.ptr);
 
-        // SAFETY: This cannot go through Deref::deref or RcInnerPtr::inner because
+        // SAFETY: This cannot go through Deref::deref or ArcInnerPtr::inner because
         // this is required to retain raw/mut provenance such that e.g. `get_mut` can
-        // write through the pointer after the Rc is recovered through `from_raw`.
+        // write through the pointer after the Arc is recovered through `from_raw`.
         unsafe { &raw mut (*ptr).data }
     }
 
@@ -2450,7 +2452,7 @@ impl<T: ?Sized, A: Allocator> Arc<T, A> {
     /// If any other `Arc` or [`Weak`] pointers to the same allocation exist, then
     /// they must not be dereferenced or have active borrows for the duration
     /// of the returned borrow, and their inner type must be exactly the same as the
-    /// inner type of this Rc (including lifetimes). This is trivially the case if no
+    /// inner type of this Arc (including lifetimes). This is trivially the case if no
     /// such pointers exist, for example immediately after `Arc::new`.
     ///
     /// # Examples
@@ -3022,7 +3024,7 @@ impl<T: ?Sized, A: Allocator> Weak<T, A> {
             // Otherwise, we're guaranteed the pointer came from a nondangling Weak.
             // SAFETY: data_offset is safe to call, as ptr references a real (potentially dropped) T.
             let offset = unsafe { data_offset(ptr) };
-            // Thus, we reverse the offset to get the whole RcInner.
+            // Thus, we reverse the offset to get the whole ArcInner.
             // SAFETY: the pointer originated from a Weak, so this offset is safe.
             unsafe { ptr.byte_sub(offset) as *mut ArcInner<T> }
         };
@@ -4015,7 +4017,7 @@ impl<T: ?Sized, A: Allocator> Unpin for Arc<T, A> {}
 /// valid instance of T, but the T is allowed to be dropped.
 unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> usize {
     // Align the unsized value to the end of the ArcInner.
-    // Because RcInner is repr(C), it will always be the last field in memory.
+    // Because ArcInner is repr(C), it will always be the last field in memory.
     // SAFETY: since the only unsized types possible are slices, trait objects,
     // and extern types, the input safety requirement is currently enough to
     // satisfy the requirements of align_of_val_raw; this is an implementation
diff --git a/library/proc_macro/src/bridge/client.rs b/library/proc_macro/src/bridge/client.rs
index e7d547966a5..92558f2b7d9 100644
--- a/library/proc_macro/src/bridge/client.rs
+++ b/library/proc_macro/src/bridge/client.rs
@@ -26,18 +26,16 @@ macro_rules! define_client_handles {
         $(
             pub(crate) struct $oty {
                 handle: handle::Handle,
-                // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual
-                // way of doing this, but that requires unstable features.
-                // rust-analyzer uses this code and avoids unstable features.
-                _marker: PhantomData<*mut ()>,
             }
 
+            impl !Send for $oty {}
+            impl !Sync for $oty {}
+
             // Forward `Drop::drop` to the inherent `drop` method.
             impl Drop for $oty {
                 fn drop(&mut self) {
                     $oty {
                         handle: self.handle,
-                        _marker: PhantomData,
                     }.drop();
                 }
             }
@@ -64,7 +62,6 @@ macro_rules! define_client_handles {
                 fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
                     $oty {
                         handle: handle::Handle::decode(r, s),
-                        _marker: PhantomData,
                     }
                 }
             }
@@ -74,12 +71,11 @@ macro_rules! define_client_handles {
             #[derive(Copy, Clone, PartialEq, Eq, Hash)]
             pub(crate) struct $ity {
                 handle: handle::Handle,
-                // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual
-                // way of doing this, but that requires unstable features.
-                // rust-analyzer uses this code and avoids unstable features.
-                _marker: PhantomData<*mut ()>,
             }
 
+            impl !Send for $ity {}
+            impl !Sync for $ity {}
+
             impl<S> Encode<S> for $ity {
                 fn encode(self, w: &mut Writer, s: &mut S) {
                     self.handle.encode(w, s);
@@ -90,7 +86,6 @@ macro_rules! define_client_handles {
                 fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
                     $ity {
                         handle: handle::Handle::decode(r, s),
-                        _marker: PhantomData,
                     }
                 }
             }
@@ -144,7 +139,7 @@ macro_rules! define_client_side {
 
                     buf.clear();
                     api_tags::Method::$name(api_tags::$name::$method).encode(&mut buf, &mut ());
-                    reverse_encode!(buf; $($arg),*);
+                    $($arg.encode(&mut buf, &mut ());)*
 
                     buf = bridge.dispatch.call(buf);
 
diff --git a/library/proc_macro/src/bridge/closure.rs b/library/proc_macro/src/bridge/closure.rs
index e0e688434dc..e5133907854 100644
--- a/library/proc_macro/src/bridge/closure.rs
+++ b/library/proc_macro/src/bridge/closure.rs
@@ -6,9 +6,7 @@ use std::marker::PhantomData;
 pub(super) struct Closure<'a, A, R> {
     call: unsafe extern "C" fn(*mut Env, A) -> R,
     env: *mut Env,
-    // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual way of doing
-    // this, but that requires unstable features. rust-analyzer uses this code
-    // and avoids unstable features.
+    // Prevent Send and Sync impls.
     //
     // The `'a` lifetime parameter represents the lifetime of `Env`.
     _marker: PhantomData<*mut &'a mut ()>,
diff --git a/library/proc_macro/src/bridge/mod.rs b/library/proc_macro/src/bridge/mod.rs
index d60a76fff5d..1b09deb6bfe 100644
--- a/library/proc_macro/src/bridge/mod.rs
+++ b/library/proc_macro/src/bridge/mod.rs
@@ -119,26 +119,6 @@ macro_rules! with_api_handle_types {
     };
 }
 
-// FIXME(eddyb) this calls `encode` for each argument, but in reverse,
-// to match the ordering in `reverse_decode`.
-macro_rules! reverse_encode {
-    ($writer:ident;) => {};
-    ($writer:ident; $first:ident $(, $rest:ident)*) => {
-        reverse_encode!($writer; $($rest),*);
-        $first.encode(&mut $writer, &mut ());
-    }
-}
-
-// FIXME(eddyb) this calls `decode` for each argument, but in reverse,
-// to avoid borrow conflicts from borrows started by `&mut` arguments.
-macro_rules! reverse_decode {
-    ($reader:ident, $s:ident;) => {};
-    ($reader:ident, $s:ident; $first:ident: $first_ty:ty $(, $rest:ident: $rest_ty:ty)*) => {
-        reverse_decode!($reader, $s; $($rest: $rest_ty),*);
-        let $first = <$first_ty>::decode(&mut $reader, $s);
-    }
-}
-
 #[allow(unsafe_code)]
 mod arena;
 #[allow(unsafe_code)]
@@ -180,13 +160,11 @@ pub struct BridgeConfig<'a> {
 
     /// If 'true', always invoke the default panic hook
     force_show_panics: bool,
-
-    // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual way of doing
-    // this, but that requires unstable features. rust-analyzer uses this code
-    // and avoids unstable features.
-    _marker: marker::PhantomData<*mut ()>,
 }
 
+impl !Send for BridgeConfig<'_> {}
+impl !Sync for BridgeConfig<'_> {}
+
 #[forbid(unsafe_code)]
 #[allow(non_camel_case_types)]
 mod api_tags {
diff --git a/library/proc_macro/src/bridge/server.rs b/library/proc_macro/src/bridge/server.rs
index 5beda7c3c96..0bb30698aa1 100644
--- a/library/proc_macro/src/bridge/server.rs
+++ b/library/proc_macro/src/bridge/server.rs
@@ -178,7 +178,7 @@ macro_rules! define_dispatcher_impl {
                     $(api_tags::Method::$name(m) => match m {
                         $(api_tags::$name::$method => {
                             let mut call_method = || {
-                                reverse_decode!(reader, handle_store; $($arg: $arg_ty),*);
+                                $(let $arg = <$arg_ty>::decode(&mut reader, handle_store);)*
                                 $name::$method(server, $($arg),*)
                             };
                             // HACK(eddyb) don't use `panic::catch_unwind` in a panic.
@@ -295,12 +295,7 @@ impl ExecutionStrategy for SameThread {
 
         let mut dispatch = |buf| dispatcher.dispatch(buf);
 
-        run_client(BridgeConfig {
-            input,
-            dispatch: (&mut dispatch).into(),
-            force_show_panics,
-            _marker: marker::PhantomData,
-        })
+        run_client(BridgeConfig { input, dispatch: (&mut dispatch).into(), force_show_panics })
     }
 }
 
@@ -331,12 +326,7 @@ where
                 client.recv().expect("server died while client waiting for reply")
             };
 
-            run_client(BridgeConfig {
-                input,
-                dispatch: (&mut dispatch).into(),
-                force_show_panics,
-                _marker: marker::PhantomData,
-            })
+            run_client(BridgeConfig { input, dispatch: (&mut dispatch).into(), force_show_panics })
         });
 
         while let Some(b) = server.recv() {
diff --git a/library/proc_macro/src/lib.rs b/library/proc_macro/src/lib.rs
index 162b4fdcc8a..613abd7024e 100644
--- a/library/proc_macro/src/lib.rs
+++ b/library/proc_macro/src/lib.rs
@@ -27,7 +27,6 @@
 #![feature(panic_can_unwind)]
 #![feature(restricted_std)]
 #![feature(rustc_attrs)]
-#![feature(stmt_expr_attributes)]
 #![feature(extend_one)]
 #![recursion_limit = "256"]
 #![allow(internal_features)]
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 718c7c2e3b1..6e3b1e6e47d 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -1412,6 +1412,99 @@ impl PathBuf {
         }
     }
 
+    /// Sets whether the path has a trailing [separator](MAIN_SEPARATOR).
+    ///
+    /// The value returned by [`has_trailing_sep`](Path::has_trailing_sep) will be equivalent to
+    /// the provided value if possible.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_trailing_sep)]
+    /// use std::path::PathBuf;
+    ///
+    /// let mut p = PathBuf::from("dir");
+    ///
+    /// assert!(!p.has_trailing_sep());
+    /// p.set_trailing_sep(false);
+    /// assert!(!p.has_trailing_sep());
+    /// p.set_trailing_sep(true);
+    /// assert!(p.has_trailing_sep());
+    /// p.set_trailing_sep(false);
+    /// assert!(!p.has_trailing_sep());
+    ///
+    /// p = PathBuf::from("/");
+    /// assert!(p.has_trailing_sep());
+    /// p.set_trailing_sep(false);
+    /// assert!(p.has_trailing_sep());
+    /// ```
+    #[unstable(feature = "path_trailing_sep", issue = "142503")]
+    pub fn set_trailing_sep(&mut self, trailing_sep: bool) {
+        if trailing_sep { self.push_trailing_sep() } else { self.pop_trailing_sep() }
+    }
+
+    /// Adds a trailing [separator](MAIN_SEPARATOR) to the path.
+    ///
+    /// This acts similarly to [`Path::with_trailing_sep`], but mutates the underlying `PathBuf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_trailing_sep)]
+    /// use std::ffi::OsStr;
+    /// use std::path::PathBuf;
+    ///
+    /// let mut p = PathBuf::from("dir");
+    ///
+    /// assert!(!p.has_trailing_sep());
+    /// p.push_trailing_sep();
+    /// assert!(p.has_trailing_sep());
+    /// p.push_trailing_sep();
+    /// assert!(p.has_trailing_sep());
+    ///
+    /// p = PathBuf::from("dir/");
+    /// p.push_trailing_sep();
+    /// assert_eq!(p.as_os_str(), OsStr::new("dir/"));
+    /// ```
+    #[unstable(feature = "path_trailing_sep", issue = "142503")]
+    pub fn push_trailing_sep(&mut self) {
+        if !self.has_trailing_sep() {
+            self.push("");
+        }
+    }
+
+    /// Removes a trailing [separator](MAIN_SEPARATOR) from the path, if possible.
+    ///
+    /// This acts similarly to [`Path::trim_trailing_sep`], but mutates the underlying `PathBuf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_trailing_sep)]
+    /// use std::ffi::OsStr;
+    /// use std::path::PathBuf;
+    ///
+    /// let mut p = PathBuf::from("dir//");
+    ///
+    /// assert!(p.has_trailing_sep());
+    /// assert_eq!(p.as_os_str(), OsStr::new("dir//"));
+    /// p.pop_trailing_sep();
+    /// assert!(!p.has_trailing_sep());
+    /// assert_eq!(p.as_os_str(), OsStr::new("dir"));
+    /// p.pop_trailing_sep();
+    /// assert!(!p.has_trailing_sep());
+    /// assert_eq!(p.as_os_str(), OsStr::new("dir"));
+    ///
+    /// p = PathBuf::from("/");
+    /// assert!(p.has_trailing_sep());
+    /// p.pop_trailing_sep();
+    /// assert!(p.has_trailing_sep());
+    /// ```
+    #[unstable(feature = "path_trailing_sep", issue = "142503")]
+    pub fn pop_trailing_sep(&mut self) {
+        self.inner.truncate(self.trim_trailing_sep().as_os_str().len());
+    }
+
     /// Updates [`self.file_name`] to `file_name`.
     ///
     /// If [`self.file_name`] was [`None`], this is equivalent to pushing
@@ -1610,7 +1703,7 @@ impl PathBuf {
         let new = extension.as_encoded_bytes();
         if !new.is_empty() {
             // truncate until right after the file name
-            // this is necessary for trimming the trailing slash
+            // this is necessary for trimming the trailing separator
             let end_file_name = file_name[file_name.len()..].as_ptr().addr();
             let start = self.inner.as_encoded_bytes().as_ptr().addr();
             self.inner.truncate(end_file_name.wrapping_sub(start));
@@ -2755,6 +2848,94 @@ impl Path {
         self.file_name().map(rsplit_file_at_dot).and_then(|(before, after)| before.and(after))
     }
 
+    /// Checks whether the path ends in a trailing [separator](MAIN_SEPARATOR).
+    ///
+    /// This is generally done to ensure that a path is treated as a directory, not a file,
+    /// although it does not actually guarantee that such a path is a directory on the underlying
+    /// file system.
+    ///
+    /// Despite this behavior, two paths are still considered the same in Rust whether they have a
+    /// trailing separator or not.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_trailing_sep)]
+    /// use std::path::Path;
+    ///
+    /// assert!(Path::new("dir/").has_trailing_sep());
+    /// assert!(!Path::new("file.rs").has_trailing_sep());
+    /// ```
+    #[unstable(feature = "path_trailing_sep", issue = "142503")]
+    #[must_use]
+    #[inline]
+    pub fn has_trailing_sep(&self) -> bool {
+        self.as_os_str().as_encoded_bytes().last().copied().is_some_and(is_sep_byte)
+    }
+
+    /// Ensures that a path has a trailing [separator](MAIN_SEPARATOR),
+    /// allocating a [`PathBuf`] if necessary.
+    ///
+    /// The resulting path will return true for [`has_trailing_sep`](Self::has_trailing_sep).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_trailing_sep)]
+    /// use std::ffi::OsStr;
+    /// use std::path::Path;
+    ///
+    /// assert_eq!(Path::new("dir//").with_trailing_sep().as_os_str(), OsStr::new("dir//"));
+    /// assert_eq!(Path::new("dir/").with_trailing_sep().as_os_str(), OsStr::new("dir/"));
+    /// assert!(!Path::new("dir").has_trailing_sep());
+    /// assert!(Path::new("dir").with_trailing_sep().has_trailing_sep());
+    /// ```
+    #[unstable(feature = "path_trailing_sep", issue = "142503")]
+    #[must_use]
+    #[inline]
+    pub fn with_trailing_sep(&self) -> Cow<'_, Path> {
+        if self.has_trailing_sep() { Cow::Borrowed(self) } else { Cow::Owned(self.join("")) }
+    }
+
+    /// Trims a trailing [separator](MAIN_SEPARATOR) from a path, if possible.
+    ///
+    /// The resulting path will return false for [`has_trailing_sep`](Self::has_trailing_sep) for
+    /// most paths.
+    ///
+    /// Some paths, like `/`, cannot be trimmed in this way.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_trailing_sep)]
+    /// use std::ffi::OsStr;
+    /// use std::path::Path;
+    ///
+    /// assert_eq!(Path::new("dir//").trim_trailing_sep().as_os_str(), OsStr::new("dir"));
+    /// assert_eq!(Path::new("dir/").trim_trailing_sep().as_os_str(), OsStr::new("dir"));
+    /// assert_eq!(Path::new("dir").trim_trailing_sep().as_os_str(), OsStr::new("dir"));
+    /// assert_eq!(Path::new("/").trim_trailing_sep().as_os_str(), OsStr::new("/"));
+    /// assert_eq!(Path::new("//").trim_trailing_sep().as_os_str(), OsStr::new("//"));
+    /// ```
+    #[unstable(feature = "path_trailing_sep", issue = "142503")]
+    #[must_use]
+    #[inline]
+    pub fn trim_trailing_sep(&self) -> &Path {
+        if self.has_trailing_sep() && (!self.has_root() || self.parent().is_some()) {
+            let mut bytes = self.inner.as_encoded_bytes();
+            while let Some((last, init)) = bytes.split_last()
+                && is_sep_byte(*last)
+            {
+                bytes = init;
+            }
+
+            // SAFETY: Trimming trailing ASCII bytes will retain the validity of the string.
+            Path::new(unsafe { OsStr::from_encoded_bytes_unchecked(bytes) })
+        } else {
+            self
+        }
+    }
+
     /// Creates an owned [`PathBuf`] with `path` adjoined to `self`.
     ///
     /// If `path` is absolute, it replaces the current path.
@@ -2907,7 +3088,7 @@ impl Path {
     ///   `a/b` all have `a` and `b` as components, but `./a/b` starts with
     ///   an additional [`CurDir`] component.
     ///
-    /// * A trailing slash is normalized away, `/a/b` and `/a/b/` are equivalent.
+    /// * Trailing separators are normalized away, so `/a/b` and `/a/b/` are equivalent.
     ///
     /// Note that no other normalization takes place; in particular, `a/c`
     /// and `a/b/../c` are distinct, to account for the possibility that `b`
@@ -3718,7 +3899,7 @@ impl Error for NormalizeError {}
 ///
 /// On POSIX platforms, the path is resolved using [POSIX semantics][posix-semantics],
 /// except that it stops short of resolving symlinks. This means it will keep `..`
-/// components and trailing slashes.
+/// components and trailing separators.
 ///
 /// On Windows, for verbatim paths, this will simply return the path as given. For other
 /// paths, this is currently equivalent to calling
diff --git a/library/std/tests/path.rs b/library/std/tests/path.rs
index 837a14b808f..c60edbdf961 100644
--- a/library/std/tests/path.rs
+++ b/library/std/tests/path.rs
@@ -1,4 +1,9 @@
-#![feature(clone_to_uninit, maybe_uninit_slice, normalize_lexically)]
+// tidy-alphabetical-start
+#![feature(clone_to_uninit)]
+#![feature(maybe_uninit_slice)]
+#![feature(normalize_lexically)]
+#![feature(path_trailing_sep)]
+// tidy-alphabetical-end
 
 use std::clone::CloneToUninit;
 use std::ffi::OsStr;
@@ -2542,3 +2547,34 @@ fn compare_path_like_to_str_like() {
     assert!(path_buf == s);
     assert!(s == path_buf);
 }
+
+#[test]
+fn test_trim_trailing_sep() {
+    assert_eq!(Path::new("/").trim_trailing_sep().as_os_str(), OsStr::new("/"));
+    assert_eq!(Path::new("//").trim_trailing_sep().as_os_str(), OsStr::new("//"));
+    assert_eq!(Path::new("").trim_trailing_sep().as_os_str(), OsStr::new(""));
+    assert_eq!(Path::new(".").trim_trailing_sep().as_os_str(), OsStr::new("."));
+    assert_eq!(Path::new("./").trim_trailing_sep().as_os_str(), OsStr::new("."));
+    assert_eq!(Path::new(".//").trim_trailing_sep().as_os_str(), OsStr::new("."));
+    assert_eq!(Path::new("..").trim_trailing_sep().as_os_str(), OsStr::new(".."));
+    assert_eq!(Path::new("../").trim_trailing_sep().as_os_str(), OsStr::new(".."));
+    assert_eq!(Path::new("..//").trim_trailing_sep().as_os_str(), OsStr::new(".."));
+
+    #[cfg(any(windows, target_os = "cygwin"))]
+    {
+        assert_eq!(Path::new("\\").trim_trailing_sep().as_os_str(), OsStr::new("\\"));
+        assert_eq!(Path::new("\\\\").trim_trailing_sep().as_os_str(), OsStr::new("\\\\"));
+        assert_eq!(Path::new("c:/").trim_trailing_sep().as_os_str(), OsStr::new("c:/"));
+        assert_eq!(Path::new("c://").trim_trailing_sep().as_os_str(), OsStr::new("c://"));
+        assert_eq!(Path::new("c:./").trim_trailing_sep().as_os_str(), OsStr::new("c:."));
+        assert_eq!(Path::new("c:.//").trim_trailing_sep().as_os_str(), OsStr::new("c:."));
+        assert_eq!(Path::new("c:../").trim_trailing_sep().as_os_str(), OsStr::new("c:.."));
+        assert_eq!(Path::new("c:..//").trim_trailing_sep().as_os_str(), OsStr::new("c:.."));
+        assert_eq!(Path::new("c:\\").trim_trailing_sep().as_os_str(), OsStr::new("c:\\"));
+        assert_eq!(Path::new("c:\\\\").trim_trailing_sep().as_os_str(), OsStr::new("c:\\\\"));
+        assert_eq!(Path::new("c:.\\").trim_trailing_sep().as_os_str(), OsStr::new("c:."));
+        assert_eq!(Path::new("c:.\\\\").trim_trailing_sep().as_os_str(), OsStr::new("c:."));
+        assert_eq!(Path::new("c:..\\").trim_trailing_sep().as_os_str(), OsStr::new("c:.."));
+        assert_eq!(Path::new("c:..\\\\").trim_trailing_sep().as_os_str(), OsStr::new("c:.."));
+    }
+}
diff --git a/src/bootstrap/src/core/build_steps/doc.rs b/src/bootstrap/src/core/build_steps/doc.rs
index 7865b685659..37462c63f1b 100644
--- a/src/bootstrap/src/core/build_steps/doc.rs
+++ b/src/bootstrap/src/core/build_steps/doc.rs
@@ -1024,12 +1024,9 @@ macro_rules! tool_doc {
                         run.builder.ensure(Rustc::from_build_compiler(run.builder, compilers.build_compiler(), target));
                         compilers.build_compiler()
                     }
-                    Mode::ToolBootstrap => {
-                        // bootstrap/host tools should be documented with the stage 0 compiler
-                        prepare_doc_compiler(run.builder, run.builder.host_target, 1)
-                    }
                     Mode::ToolTarget => {
-                        // target tools should be documented with the in-tree compiler
+                        // when shipping multiple docs together in one folder,
+                        // they all need to use the same rustdoc version
                         prepare_doc_compiler(run.builder, run.builder.host_target, run.builder.top_stage)
                     }
                     _ => {
@@ -1132,7 +1129,11 @@ macro_rules! tool_doc {
 tool_doc!(
     BuildHelper,
     "src/build_helper",
-    mode = Mode::ToolBootstrap,
+    // ideally, this would use ToolBootstrap,
+    // but we distribute these docs together in the same folder
+    // as a bunch of stage1 tools, and you can't mix rustdoc versions
+    // because that breaks cross-crate data (particularly search)
+    mode = Mode::ToolTarget,
     is_library = true,
     crates = ["build_helper"]
 );
@@ -1175,25 +1176,25 @@ tool_doc!(
     // "specialization" feature in its build script when it detects a nightly toolchain.
     allow_features: "specialization"
 );
-tool_doc!(Tidy, "src/tools/tidy", mode = Mode::ToolBootstrap, crates = ["tidy"]);
+tool_doc!(Tidy, "src/tools/tidy", mode = Mode::ToolTarget, crates = ["tidy"]);
 tool_doc!(
     Bootstrap,
     "src/bootstrap",
-    mode = Mode::ToolBootstrap,
+    mode = Mode::ToolTarget,
     is_library = true,
     crates = ["bootstrap"]
 );
 tool_doc!(
     RunMakeSupport,
     "src/tools/run-make-support",
-    mode = Mode::ToolBootstrap,
+    mode = Mode::ToolTarget,
     is_library = true,
     crates = ["run_make_support"]
 );
 tool_doc!(
     Compiletest,
     "src/tools/compiletest",
-    mode = Mode::ToolBootstrap,
+    mode = Mode::ToolTarget,
     is_library = true,
     crates = ["compiletest"]
 );
diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 9fc4ce669c2..a404aec5120 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -10,7 +10,7 @@ use crate::core::config::flags::Color;
 use crate::utils::build_stamp;
 use crate::utils::helpers::{self, LldThreads, check_cfg_arg, linker_args, linker_flags};
 use crate::{
-    BootstrapCommand, CLang, Compiler, Config, DocTests, DryRun, EXTRA_CHECK_CFGS, GitRepo, Mode,
+    BootstrapCommand, CLang, Compiler, Config, DryRun, EXTRA_CHECK_CFGS, GitRepo, Mode,
     RemapScheme, TargetSelection, command, prepare_behaviour_dump_dir, t,
 };
 
@@ -851,8 +851,6 @@ impl Builder<'_> {
 
         rustflags.arg("-Zmacro-backtrace");
 
-        let want_rustdoc = self.doc_tests != DocTests::No;
-
         // Clear the output directory if the real rustc we're using has changed;
         // Cargo cannot detect this as it thinks rustc is bootstrap/debug/rustc.
         //
@@ -881,7 +879,8 @@ impl Builder<'_> {
             .env("RUSTC_REAL", self.rustc(compiler))
             .env("RUSTC_STAGE", build_compiler_stage.to_string())
             .env("RUSTC_SYSROOT", sysroot)
-            .env("RUSTC_LIBDIR", libdir)
+            .env("RUSTC_LIBDIR", &libdir)
+            .env("RUSTDOC_LIBDIR", libdir)
             .env("RUSTDOC", self.bootstrap_out.join("rustdoc"))
             .env("RUSTDOC_REAL", rustdoc_path)
             .env("RUSTC_ERROR_METADATA_DST", self.extended_error_dir());
@@ -919,11 +918,6 @@ impl Builder<'_> {
             rustflags.arg(&format!("-Zstack-protector={stack_protector}"));
         }
 
-        if !matches!(cmd_kind, Kind::Build | Kind::Check | Kind::Clippy | Kind::Fix) && want_rustdoc
-        {
-            cargo.env("RUSTDOC_LIBDIR", self.rustc_libdir(compiler));
-        }
-
         let debuginfo_level = match mode {
             Mode::Rustc | Mode::Codegen => self.config.rust_debuginfo_level_rustc,
             Mode::Std => self.config.rust_debuginfo_level_std,
diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index 88df469e9a0..3306435758b 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -1158,13 +1158,12 @@ mod snapshot {
         [doc] embedded-book (book) <host>
         [doc] edition-guide (book) <host>
         [doc] style-guide (book) <host>
-        [build] rustdoc 0 <host>
-        [doc] rustc 0 <host> -> Tidy 1 <host>
-        [doc] rustc 0 <host> -> Bootstrap 1 <host>
+        [doc] rustc 1 <host> -> Tidy 2 <host>
+        [doc] rustc 1 <host> -> Bootstrap 2 <host>
         [doc] rustc 1 <host> -> releases 2 <host>
-        [doc] rustc 0 <host> -> RunMakeSupport 1 <host>
-        [doc] rustc 0 <host> -> BuildHelper 1 <host>
-        [doc] rustc 0 <host> -> Compiletest 1 <host>
+        [doc] rustc 1 <host> -> RunMakeSupport 2 <host>
+        [doc] rustc 1 <host> -> BuildHelper 2 <host>
+        [doc] rustc 1 <host> -> Compiletest 2 <host>
         [build] rustc 0 <host> -> RustInstaller 1 <host>
         "
         );
@@ -2686,8 +2685,11 @@ mod snapshot {
                 .path("src/tools/compiletest")
                 .stage(2)
                 .render_steps(), @r"
-        [build] rustdoc 0 <host>
-        [doc] rustc 0 <host> -> Compiletest 1 <host>
+        [build] llvm <host>
+        [build] rustc 0 <host> -> rustc 1 <host>
+        [build] rustc 1 <host> -> std 1 <host>
+        [build] rustdoc 1 <host>
+        [doc] rustc 1 <host> -> Compiletest 2 <host>
         ");
     }
 
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 8303699ce8a..4384ec76769 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -430,7 +430,8 @@ auto:
       # Ensure that host tooling is built to support our minimum support macOS version.
       MACOSX_DEPLOYMENT_TARGET: 10.12
       MACOSX_STD_DEPLOYMENT_TARGET: 10.12
-      SELECT_XCODE: /Applications/Xcode_15.2.app
+      SELECT_XCODE: /Applications/Xcode_15.4.app
+      USE_XCODE_CLANG: 1
       DIST_REQUIRE_ALL_TOOLS: 1
       CODEGEN_BACKENDS: llvm,cranelift
     <<: *job-macos
@@ -450,21 +451,24 @@ auto:
 
   - name: dist-aarch64-apple
     env:
-      SCRIPT: ./x.py dist bootstrap --include-default-paths --host=aarch64-apple-darwin --target=aarch64-apple-darwin
+      SCRIPT: >-
+        ./x.py dist bootstrap
+        --include-default-paths
+        --host=aarch64-apple-darwin
+        --target=aarch64-apple-darwin
       RUST_CONFIGURE_ARGS: >-
         --enable-full-tools
         --enable-sanitizers
         --enable-profiler
         --set rust.jemalloc
-        --set llvm.ninja=false
         --set rust.lto=thin
         --set rust.codegen-units=1
-      SELECT_XCODE: /Applications/Xcode_15.4.app
-      USE_XCODE_CLANG: 1
       # Aarch64 tooling only needs to support macOS 11.0 and up as nothing else
       # supports the hardware.
       MACOSX_DEPLOYMENT_TARGET: 11.0
       MACOSX_STD_DEPLOYMENT_TARGET: 11.0
+      SELECT_XCODE: /Applications/Xcode_15.4.app
+      USE_XCODE_CLANG: 1
       DIST_REQUIRE_ALL_TOOLS: 1
       CODEGEN_BACKENDS: llvm,cranelift
     <<: *job-macos
diff --git a/src/librustdoc/passes/mod.rs b/src/librustdoc/passes/mod.rs
index 475d05b7d0e..f45df8d2d0d 100644
--- a/src/librustdoc/passes/mod.rs
+++ b/src/librustdoc/passes/mod.rs
@@ -77,11 +77,11 @@ pub(crate) enum Condition {
 pub(crate) const PASSES: &[Pass] = &[
     CHECK_DOC_CFG,
     CHECK_DOC_TEST_VISIBILITY,
+    PROPAGATE_DOC_CFG,
     STRIP_ALIASED_NON_LOCAL,
     STRIP_HIDDEN,
     STRIP_PRIVATE,
     STRIP_PRIV_IMPORTS,
-    PROPAGATE_DOC_CFG,
     PROPAGATE_STABILITY,
     COLLECT_INTRA_DOC_LINKS,
     COLLECT_TRAIT_IMPLS,
@@ -94,11 +94,11 @@ pub(crate) const DEFAULT_PASSES: &[ConditionalPass] = &[
     ConditionalPass::always(COLLECT_TRAIT_IMPLS),
     ConditionalPass::always(CHECK_DOC_TEST_VISIBILITY),
     ConditionalPass::always(CHECK_DOC_CFG),
+    ConditionalPass::always(COLLECT_INTRA_DOC_LINKS),
     ConditionalPass::always(STRIP_ALIASED_NON_LOCAL),
     ConditionalPass::new(STRIP_HIDDEN, WhenNotDocumentHidden),
     ConditionalPass::new(STRIP_PRIVATE, WhenNotDocumentPrivate),
     ConditionalPass::new(STRIP_PRIV_IMPORTS, WhenDocumentPrivate),
-    ConditionalPass::always(COLLECT_INTRA_DOC_LINKS),
     ConditionalPass::always(PROPAGATE_DOC_CFG),
     ConditionalPass::always(PROPAGATE_STABILITY),
     ConditionalPass::always(RUN_LINTS),
diff --git a/tests/codegen-llvm/unwind-abis/c-unwind-abi-panic-abort.rs b/tests/codegen-llvm/unwind-abis/c-unwind-abi-panic-abort.rs
index 8d2745ba2f7..2ce1d1b2e00 100644
--- a/tests/codegen-llvm/unwind-abis/c-unwind-abi-panic-abort.rs
+++ b/tests/codegen-llvm/unwind-abis/c-unwind-abi-panic-abort.rs
@@ -1,4 +1,9 @@
 //@ compile-flags: -C panic=abort
+//@ revisions: NONWASM WASM WASMEXN
+//@ [NONWASM] ignore-wasm32
+//@ [WASM] only-wasm32
+//@ [WASMEXN] only-wasm32
+//@ [WASMEXN] compile-flags: -Ctarget-feature=+exception-handling
 
 // Test that `nounwind` attributes are also applied to extern `C-unwind` Rust functions
 // when the code is compiled with `panic=abort`.
@@ -9,7 +14,9 @@
 #[no_mangle]
 pub unsafe extern "C-unwind" fn rust_item_that_can_unwind() {
     // Handle both legacy and v0 symbol mangling.
-    // CHECK: call void @{{.*core9panicking19panic_cannot_unwind}}
+    // NONWASM: call void @{{.*core9panicking19panic_cannot_unwind}}
+    // WASMEXN: call void @{{.*core9panicking19panic_cannot_unwind}}
+    // WASM-NOT: call void @{{.*core9panicking19panic_cannot_unwind}}
     may_unwind();
 }
 
diff --git a/tests/codegen-llvm/unwind-and-panic-abort.rs b/tests/codegen-llvm/unwind-and-panic-abort.rs
index 8efa140058a..c2838be00af 100644
--- a/tests/codegen-llvm/unwind-and-panic-abort.rs
+++ b/tests/codegen-llvm/unwind-and-panic-abort.rs
@@ -1,4 +1,9 @@
 //@ compile-flags: -C panic=abort
+//@ revisions: NONWASM WASM WASMEXN
+//@ [NONWASM] ignore-wasm32
+//@ [WASM] only-wasm32
+//@ [WASMEXN] only-wasm32
+//@ [WASMEXN] compile-flags: -Ctarget-feature=+exception-handling
 
 #![crate_type = "lib"]
 
@@ -9,7 +14,9 @@ extern "C-unwind" {
 // CHECK: Function Attrs:{{.*}}nounwind
 // CHECK-NEXT: define{{.*}}void @foo
 // Handle both legacy and v0 symbol mangling.
-// CHECK: call void @{{.*core9panicking19panic_cannot_unwind}}
+// NONWASM: call void @{{.*core9panicking19panic_cannot_unwind}}
+// WASMEXN: call void @{{.*core9panicking19panic_cannot_unwind}}
+// WASM-NOT: call void @{{.*core9panicking19panic_cannot_unwind}}
 #[no_mangle]
 pub unsafe extern "C" fn foo() {
     bar();
diff --git a/tests/codegen-llvm/wasm_exceptions.rs b/tests/codegen-llvm/wasm_exceptions.rs
index 796b69b722b..e718f599a3c 100644
--- a/tests/codegen-llvm/wasm_exceptions.rs
+++ b/tests/codegen-llvm/wasm_exceptions.rs
@@ -1,8 +1,9 @@
 //@ only-wasm32
-//@ compile-flags: -C panic=unwind -Z emscripten-wasm-eh
+//@ revisions: WASM WASMEXN
+//@ [WASMEXN] compile-flags: -C panic=unwind -Z emscripten-wasm-eh
 
 #![crate_type = "lib"]
-#![feature(core_intrinsics, wasm_exception_handling_intrinsics)]
+#![feature(core_intrinsics, wasm_exception_handling_intrinsics, link_llvm_intrinsics)]
 
 extern "C-unwind" {
     fn may_panic();
@@ -22,7 +23,8 @@ impl Drop for LogOnDrop {
     }
 }
 
-// CHECK-LABEL: @test_cleanup() {{.*}} @__gxx_wasm_personality_v0
+// WASM-LABEL: @test_cleanup() {{.*}}
+// WASMEXN-LABEL: @test_cleanup() {{.*}} @__gxx_wasm_personality_v0
 #[no_mangle]
 pub fn test_cleanup() {
     let _log_on_drop = LogOnDrop;
@@ -30,12 +32,16 @@ pub fn test_cleanup() {
         may_panic();
     }
 
-    // CHECK-NOT: call
-    // CHECK: invoke void @may_panic()
-    // CHECK: %cleanuppad = cleanuppad within none []
+    // WASMEXN-NOT: call
+    // WASMEXN: invoke void @may_panic()
+    // WASMEXN: %cleanuppad = cleanuppad within none []
+    //
+    // WASM: call void @may_panic()
+    // WASM-NOT: invoke void @may_panic()
 }
 
-// CHECK-LABEL: @test_rtry() {{.*}} @__gxx_wasm_personality_v0
+// WASM-LABEL: @test_rtry() {{.*}}
+// WASMEXN-LABEL: @test_rtry() {{.*}} @__gxx_wasm_personality_v0
 #[no_mangle]
 pub fn test_rtry() {
     unsafe {
@@ -51,23 +57,40 @@ pub fn test_rtry() {
         );
     }
 
-    // CHECK-NOT: call
-    // CHECK: invoke void @may_panic()
-    // CHECK: {{.*}} = catchswitch within none [label {{.*}}] unwind to caller
-    // CHECK: {{.*}} = catchpad within {{.*}} [ptr null]
-    // CHECK: catchret
+    // WASMEXN-NOT: call
+    // WASMEXN: invoke void @may_panic()
+    // WASMEXN: {{.*}} = catchswitch within none [label {{.*}}] unwind to caller
+    // WASMEXN: {{.*}} = catchpad within {{.*}} [ptr null]
+    // WASMEXN: catchret
+
+    // WASM: call void @may_panic()
+    // WASM-NOT: invoke void @may_panic()
+    // WASM-NOT: catchswitch
+    // WASM-NOT: catchpad
+    // WASM-NOT: catchret
 }
 
 // Make sure the intrinsic is not inferred as nounwind. This is a regression test for #132416.
-// CHECK-LABEL: @test_intrinsic() {{.*}} @__gxx_wasm_personality_v0
+//
+// Note that this test uses the raw `wasm_throw` intrinsic because the one from
+// libstd was built with `-Cpanic=abort` and it's technically not valid to use
+// when this crate is compiled with `-Cpanic=unwind`.
+//
+// WASMEXN-LABEL: @test_intrinsic() {{.*}} @__gxx_wasm_personality_v0
 #[no_mangle]
+#[cfg(wasmexn)]
 pub fn test_intrinsic() {
     let _log_on_drop = LogOnDrop;
+
+    unsafe extern "C-unwind" {
+        #[link_name = "llvm.wasm.throw"]
+        fn wasm_throw(tag: i32, ptr: *mut u8) -> !;
+    }
     unsafe {
-        core::arch::wasm32::throw::<0>(core::ptr::null_mut());
+        wasm_throw(0, core::ptr::null_mut());
     }
 
-    // CHECK-NOT: call
-    // CHECK: invoke void @llvm.wasm.throw(i32 noundef 0, ptr noundef null)
-    // CHECK: %cleanuppad = cleanuppad within none []
+    // WASMEXN-NOT: call
+    // WASMEXN: invoke void @llvm.wasm.throw(i32 noundef 0, ptr noundef null)
+    // WASMEXN: %cleanuppad = cleanuppad within none []
 }
diff --git a/tests/rustdoc-ui/issues/issue-91713.stdout b/tests/rustdoc-ui/issues/issue-91713.stdout
index 30aadfe89f4..d34714be6c9 100644
--- a/tests/rustdoc-ui/issues/issue-91713.stdout
+++ b/tests/rustdoc-ui/issues/issue-91713.stdout
@@ -1,11 +1,11 @@
 Available passes for running rustdoc:
        check-doc-cfg - checks `#[doc(cfg(...))]` for stability feature and unexpected cfgs
 check_doc_test_visibility - run various visibility-related lints on doctests
+   propagate-doc-cfg - propagates `#[doc(cfg(...))]` to child items
 strip-aliased-non-local - strips all non-local private aliased items from the output
         strip-hidden - strips all `#[doc(hidden)]` items from the output
        strip-private - strips all private items from a crate which cannot be seen externally, implies strip-priv-imports
   strip-priv-imports - strips all private import statements (`use`, `extern crate`) from a crate
-   propagate-doc-cfg - propagates `#[doc(cfg(...))]` to child items
  propagate-stability - propagates stability to child items
 collect-intra-doc-links - resolves intra-doc links
  collect-trait-impls - retrieves trait impls for items in the crate
@@ -16,11 +16,11 @@ Default passes for rustdoc:
  collect-trait-impls
 check_doc_test_visibility
        check-doc-cfg
+collect-intra-doc-links
 strip-aliased-non-local
         strip-hidden  (when not --document-hidden-items)
        strip-private  (when not --document-private-items)
   strip-priv-imports  (when --document-private-items)
-collect-intra-doc-links
    propagate-doc-cfg
  propagate-stability
            run-lints
diff --git a/tests/rustdoc/doc-auto-cfg-public-in-private.rs b/tests/rustdoc/doc-auto-cfg-public-in-private.rs
new file mode 100644
index 00000000000..b78e3f1b932
--- /dev/null
+++ b/tests/rustdoc/doc-auto-cfg-public-in-private.rs
@@ -0,0 +1,16 @@
+// This test ensures that even though private items are removed from generated docs,
+// their `cfg`s will still impact their child items.
+
+#![feature(doc_cfg)]
+#![crate_name = "foo"]
+
+pub struct X;
+
+#[cfg(not(feature = "blob"))]
+fn foo() {
+    impl X {
+        //@ has 'foo/struct.X.html'
+        //@ has - '//*[@class="stab portability"]' 'Available on non-crate feature blob only.'
+        pub fn bar() {}
+    }
+}
diff --git a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs
index 19a31d1889b..f97ec779b32 100644
--- a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs
+++ b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.rs
@@ -44,4 +44,18 @@ fn through_field_and_ref_move<'a>(x: &S<'a>) {
     outlives::<'a>(call_once(c)); //~ ERROR explicit lifetime required in the type of `x`
 }
 
+struct T;
+impl T {
+    fn outlives<'a>(&'a self, _: impl Sized + 'a) {}
+}
+fn through_method<'a>(x: &'a i32) {
+    let c = async || { println!("{}", *x); }; //~ ERROR `x` does not live long enough
+    T.outlives::<'a>(c());
+    T.outlives::<'a>(call_once(c));
+
+    let c = async move || { println!("{}", *x); };
+    T.outlives::<'a>(c()); //~ ERROR `c` does not live long enough
+    T.outlives::<'a>(call_once(c));
+}
+
 fn main() {}
diff --git a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr
index b7259074bf6..4aae9807dd2 100644
--- a/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr
+++ b/tests/ui/async-await/async-closures/without-precise-captures-we-are-powerless.stderr
@@ -28,6 +28,12 @@ LL |     outlives::<'a>(c());
 LL |     outlives::<'a>(call_once(c));
 LL | }
    | - `c` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'a` introduced here
+  --> $DIR/without-precise-captures-we-are-powerless.rs:7:33
+   |
+LL | fn outlives<'a>(_: impl Sized + 'a) {}
+   |                                 ^^
 
 error[E0597]: `x` does not live long enough
   --> $DIR/without-precise-captures-we-are-powerless.rs:26:13
@@ -73,6 +79,12 @@ LL |     outlives::<'a>(c());
 LL |     outlives::<'a>(call_once(c));
 LL | }
    | - `c` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'a` introduced here
+  --> $DIR/without-precise-captures-we-are-powerless.rs:7:33
+   |
+LL | fn outlives<'a>(_: impl Sized + 'a) {}
+   |                                 ^^
 
 error[E0505]: cannot move out of `c` because it is borrowed
   --> $DIR/without-precise-captures-we-are-powerless.rs:32:30
@@ -89,6 +101,12 @@ LL |     outlives::<'a>(c());
    |     argument requires that `c` is borrowed for `'a`
 LL |     outlives::<'a>(call_once(c));
    |                              ^ move out of `c` occurs here
+   |
+note: requirement that the value outlives `'a` introduced here
+  --> $DIR/without-precise-captures-we-are-powerless.rs:7:33
+   |
+LL | fn outlives<'a>(_: impl Sized + 'a) {}
+   |                                 ^^
 
 error[E0597]: `x` does not live long enough
   --> $DIR/without-precise-captures-we-are-powerless.rs:36:13
@@ -129,6 +147,12 @@ LL |     outlives::<'a>(c());
 LL |     outlives::<'a>(call_once(c));
 LL | }
    | - `c` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'a` introduced here
+  --> $DIR/without-precise-captures-we-are-powerless.rs:7:33
+   |
+LL | fn outlives<'a>(_: impl Sized + 'a) {}
+   |                                 ^^
 
 error[E0621]: explicit lifetime required in the type of `x`
   --> $DIR/without-precise-captures-we-are-powerless.rs:44:5
@@ -141,7 +165,44 @@ help: add explicit lifetime `'a` to the type of `x`
 LL | fn through_field_and_ref_move<'a>(x: &'a S<'a>) {
    |                                       ++
 
-error: aborting due to 10 previous errors
+error[E0597]: `x` does not live long enough
+  --> $DIR/without-precise-captures-we-are-powerless.rs:52:13
+   |
+LL | fn through_method<'a>(x: &'a i32) {
+   |                   -- lifetime `'a` defined here
+LL |     let c = async || { println!("{}", *x); };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ borrowed value does not live long enough
+LL |     T.outlives::<'a>(c());
+LL |     T.outlives::<'a>(call_once(c));
+   |     ------------------------------ argument requires that `x` is borrowed for `'a`
+...
+LL | }
+   |  - `x` dropped here while still borrowed
+
+error[E0597]: `c` does not live long enough
+  --> $DIR/without-precise-captures-we-are-powerless.rs:57:22
+   |
+LL | fn through_method<'a>(x: &'a i32) {
+   |                   -- lifetime `'a` defined here
+...
+LL |     let c = async move || { println!("{}", *x); };
+   |         - binding `c` declared here
+LL |     T.outlives::<'a>(c());
+   |     -----------------^---
+   |     |                |
+   |     |                borrowed value does not live long enough
+   |     argument requires that `c` is borrowed for `'a`
+LL |     T.outlives::<'a>(call_once(c));
+LL | }
+   | - `c` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'a` introduced here
+  --> $DIR/without-precise-captures-we-are-powerless.rs:49:47
+   |
+LL |     fn outlives<'a>(&'a self, _: impl Sized + 'a) {}
+   |                                               ^^
+
+error: aborting due to 12 previous errors
 
 Some errors have detailed explanations: E0505, E0597, E0621.
 For more information about an error, try `rustc --explain E0505`.
diff --git a/tests/ui/borrowck/fn-item-check-type-params.stderr b/tests/ui/borrowck/fn-item-check-type-params.stderr
index aafb7e66ef5..7a0a7752a14 100644
--- a/tests/ui/borrowck/fn-item-check-type-params.stderr
+++ b/tests/ui/borrowck/fn-item-check-type-params.stderr
@@ -27,6 +27,12 @@ LL |     want(&String::new(), extend_lt);
    |     |     |
    |     |     creates a temporary value which is freed while still in use
    |     argument requires that borrow lasts for `'static`
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/fn-item-check-type-params.rs:47:33
+   |
+LL |     fn want<I, O>(_: I, _: impl Fn(I) -> O) {}
+   |                                 ^^^^^^^^^^
 
 error[E0716]: temporary value dropped while borrowed
   --> $DIR/fn-item-check-type-params.rs:54:26
@@ -36,6 +42,12 @@ LL |     let val = extend_lt(&String::from("blah blah blah"));
    |               |          |
    |               |          creates a temporary value which is freed while still in use
    |               argument requires that borrow lasts for `'static`
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/fn-item-check-type-params.rs:22:21
+   |
+LL |     (T, Option<U>): Displayable,
+   |                     ^^^^^^^^^^^
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/borrowck/implementation-not-general-enough-ice-133252.stderr b/tests/ui/borrowck/implementation-not-general-enough-ice-133252.stderr
index 5389226f7a7..7b840d54ed0 100644
--- a/tests/ui/borrowck/implementation-not-general-enough-ice-133252.stderr
+++ b/tests/ui/borrowck/implementation-not-general-enough-ice-133252.stderr
@@ -22,6 +22,12 @@ LL |         force_send(async_load(&not_static));
 ...
 LL |     }
    |     - `not_static` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'1` introduced here
+  --> $DIR/implementation-not-general-enough-ice-133252.rs:16:18
+   |
+LL | fn force_send<T: Send>(_: T) {}
+   |                  ^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/borrowck/issue-17545.stderr b/tests/ui/borrowck/issue-17545.stderr
index 45e977e3947..63fd57cd233 100644
--- a/tests/ui/borrowck/issue-17545.stderr
+++ b/tests/ui/borrowck/issue-17545.stderr
@@ -10,6 +10,9 @@ LL | |     ));
    | |      -- temporary value is freed at the end of this statement
    | |______|
    |        argument requires that borrow lasts for `'a`
+   |
+note: requirement that the value outlives `'a` introduced here
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.rs b/tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.rs
new file mode 100644
index 00000000000..5fa5b74c0c0
--- /dev/null
+++ b/tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.rs
@@ -0,0 +1,20 @@
+//@ add-core-stubs
+//@ compile-flags: --target thumbv8m.main-none-eabi --crate-type lib -Cincremental=true
+//@ needs-llvm-components: arm
+#![feature(abi_cmse_nonsecure_call, no_core)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
+
+// A regression test for https://github.com/rust-lang/rust/issues/131639.
+// NOTE: -Cincremental=true was required for triggering the bug.
+
+fn foo() {
+    id::<extern "cmse-nonsecure-call" fn(&'a ())>(PhantomData);
+    //~^ ERROR use of undeclared lifetime name `'a`
+}
+
+fn id<T>(x: PhantomData<T>) -> PhantomData<T> {
+    x
+}
diff --git a/tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.stderr b/tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.stderr
new file mode 100644
index 00000000000..4aca17e7354
--- /dev/null
+++ b/tests/ui/cmse-nonsecure/cmse-nonsecure-call/undeclared-lifetime.stderr
@@ -0,0 +1,19 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/undeclared-lifetime.rs:14:43
+   |
+LL |     id::<extern "cmse-nonsecure-call" fn(&'a ())>(PhantomData);
+   |                                           ^^ undeclared lifetime
+   |
+   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
+help: consider making the type lifetime-generic with a new `'a` lifetime
+   |
+LL |     id::<for<'a> extern "cmse-nonsecure-call" fn(&'a ())>(PhantomData);
+   |          +++++++
+help: consider introducing lifetime `'a` here
+   |
+LL | fn foo<'a>() {
+   |       ++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0261`.
diff --git a/tests/ui/const-generics/generic_arg_infer/in-signature.stderr b/tests/ui/const-generics/generic_arg_infer/in-signature.stderr
index b6f2662a939..d7a7ab52c83 100644
--- a/tests/ui/const-generics/generic_arg_infer/in-signature.stderr
+++ b/tests/ui/const-generics/generic_arg_infer/in-signature.stderr
@@ -2,29 +2,39 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/in-signature.rs:6:21
    |
 LL | fn arr_fn() -> [u8; _] {
-   |                -----^-
-   |                |    |
-   |                |    not allowed in type signatures
-   |                help: replace with the correct return type: `[u8; 3]`
+   |                     ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn arr_fn() -> [u8; _] {
+LL + fn arr_fn() -> [u8; 3] {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/in-signature.rs:11:24
    |
 LL | fn ty_fn() -> Bar<i32, _> {
-   |               ---------^-
-   |               |        |
-   |               |        not allowed in type signatures
-   |               help: replace with the correct return type: `Bar<i32, 3>`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn ty_fn() -> Bar<i32, _> {
+LL + fn ty_fn() -> Bar<i32, 3> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/in-signature.rs:16:25
    |
 LL | fn ty_fn_mixed() -> Bar<_, _> {
-   |                     ----^--^-
-   |                     |   |  |
-   |                     |   |  not allowed in type signatures
-   |                     |   not allowed in type signatures
-   |                     help: replace with the correct return type: `Bar<i32, 3>`
+   |                         ^  ^ not allowed in type signatures
+   |                         |
+   |                         not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn ty_fn_mixed() -> Bar<_, _> {
+LL + fn ty_fn_mixed() -> Bar<i32, 3> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
   --> $DIR/in-signature.rs:21:20
diff --git a/tests/ui/error-codes/E0121.stderr b/tests/ui/error-codes/E0121.stderr
index b169373f643..074929c4e74 100644
--- a/tests/ui/error-codes/E0121.stderr
+++ b/tests/ui/error-codes/E0121.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/E0121.rs:1:13
    |
 LL | fn foo() -> _ { 5 }
-   |             ^
-   |             |
-   |             not allowed in type signatures
-   |             help: replace with the correct return type: `i32`
+   |             ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn foo() -> _ { 5 }
+LL + fn foo() -> i32 { 5 }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static variables
   --> $DIR/E0121.rs:3:13
diff --git a/tests/ui/errors/span-format_args-issue-140578.rs b/tests/ui/errors/span-format_args-issue-140578.rs
new file mode 100644
index 00000000000..8c91ded8337
--- /dev/null
+++ b/tests/ui/errors/span-format_args-issue-140578.rs
@@ -0,0 +1,32 @@
+fn check_format_args() {
+  print!("{:?} {a} {a:?}", [], a = 1 + 1);
+  //~^ ERROR type annotations needed
+}
+
+fn check_format_args_nl() {
+  println!("{:?} {a} {a:?}", [], a = 1 + 1);
+  //~^ ERROR type annotations needed
+}
+
+fn check_multi1() {
+  println!("{:?} {:?} {a} {a:?}", [], [], a = 1 + 1);
+  //~^ ERROR type annotations needed
+}
+
+fn check_multi2() {
+  println!("{:?} {:?} {a} {a:?} {b:?}", [], [], a = 1 + 1, b = []);
+  //~^ ERROR type annotations needed
+}
+
+fn check_unformatted() {
+  println!("
+  {:?} {:?}
+{a}
+{a:?}",
+        [],
+        //~^ ERROR type annotations needed
+ [],
+a = 1 + 1);
+}
+
+fn main() {}
diff --git a/tests/ui/errors/span-format_args-issue-140578.stderr b/tests/ui/errors/span-format_args-issue-140578.stderr
new file mode 100644
index 00000000000..6a273e5cd51
--- /dev/null
+++ b/tests/ui/errors/span-format_args-issue-140578.stderr
@@ -0,0 +1,43 @@
+error[E0282]: type annotations needed
+  --> $DIR/span-format_args-issue-140578.rs:2:28
+   |
+LL |   print!("{:?} {a} {a:?}", [], a = 1 + 1);
+   |                            ^^ cannot infer type
+   |
+   = note: this error originates in the macro `$crate::format_args` which comes from the expansion of the macro `print` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0282]: type annotations needed
+  --> $DIR/span-format_args-issue-140578.rs:7:30
+   |
+LL |   println!("{:?} {a} {a:?}", [], a = 1 + 1);
+   |                              ^^ cannot infer type
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0282]: type annotations needed
+  --> $DIR/span-format_args-issue-140578.rs:12:35
+   |
+LL |   println!("{:?} {:?} {a} {a:?}", [], [], a = 1 + 1);
+   |                                   ^^ cannot infer type
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0282]: type annotations needed
+  --> $DIR/span-format_args-issue-140578.rs:17:41
+   |
+LL |   println!("{:?} {:?} {a} {a:?} {b:?}", [], [], a = 1 + 1, b = []);
+   |                                         ^^ cannot infer type
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0282]: type annotations needed
+  --> $DIR/span-format_args-issue-140578.rs:26:9
+   |
+LL |         [],
+   |         ^^ cannot infer type
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/fn/issue-80179.stderr b/tests/ui/fn/issue-80179.stderr
index f5d6c44db75..95158da3cff 100644
--- a/tests/ui/fn/issue-80179.stderr
+++ b/tests/ui/fn/issue-80179.stderr
@@ -2,21 +2,26 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/issue-80179.rs:10:24
    |
 LL | fn returns_fn_ptr() -> _ {
-   |                        ^
-   |                        |
-   |                        not allowed in type signatures
-   |                        help: replace with the correct return type: `fn() -> i32`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn returns_fn_ptr() -> _ {
+LL + fn returns_fn_ptr() -> fn() -> i32 {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/issue-80179.rs:18:25
    |
 LL | fn returns_closure() -> _ {
-   |                         ^
-   |                         |
-   |                         not allowed in type signatures
-   |                         help: replace with an appropriate return type: `impl Fn() -> i32`
+   |                         ^ not allowed in type signatures
    |
    = note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
+help: replace with an appropriate return type
+   |
+LL - fn returns_closure() -> _ {
+LL + fn returns_closure() -> impl Fn() -> i32 {
+   |
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/fn/suggest-return-closure.stderr b/tests/ui/fn/suggest-return-closure.stderr
index 1860d1ca5d9..0639c23c75a 100644
--- a/tests/ui/fn/suggest-return-closure.stderr
+++ b/tests/ui/fn/suggest-return-closure.stderr
@@ -2,34 +2,40 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/suggest-return-closure.rs:1:17
    |
 LL | fn fn_once() -> _ {
-   |                 ^
-   |                 |
-   |                 not allowed in type signatures
-   |                 help: replace with an appropriate return type: `impl FnOnce()`
+   |                 ^ not allowed in type signatures
    |
    = note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
+help: replace with an appropriate return type
+   |
+LL - fn fn_once() -> _ {
+LL + fn fn_once() -> impl FnOnce() {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/suggest-return-closure.rs:13:16
    |
 LL | fn fn_mut() -> _ {
-   |                ^
-   |                |
-   |                not allowed in type signatures
-   |                help: replace with an appropriate return type: `impl FnMut(char)`
+   |                ^ not allowed in type signatures
    |
    = note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
+help: replace with an appropriate return type
+   |
+LL - fn fn_mut() -> _ {
+LL + fn fn_mut() -> impl FnMut(char) {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/suggest-return-closure.rs:33:13
    |
 LL | fn fun() -> _ {
-   |             ^
-   |             |
-   |             not allowed in type signatures
-   |             help: replace with an appropriate return type: `impl Fn() -> i32`
+   |             ^ not allowed in type signatures
    |
    = note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
+help: replace with an appropriate return type
+   |
+LL - fn fun() -> _ {
+LL + fn fun() -> impl Fn() -> i32 {
+   |
 
 error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
   --> $DIR/suggest-return-closure.rs:24:9
diff --git a/tests/ui/fn/suggest-return-future.stderr b/tests/ui/fn/suggest-return-future.stderr
index a4c8b5d8c4b..7c097e50671 100644
--- a/tests/ui/fn/suggest-return-future.stderr
+++ b/tests/ui/fn/suggest-return-future.stderr
@@ -2,19 +2,25 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/suggest-return-future.rs:7:13
    |
 LL | fn foo() -> _ {
-   |             ^
-   |             |
-   |             not allowed in type signatures
-   |             help: replace with an appropriate return type: `impl Future<Output = i32>`
+   |             ^ not allowed in type signatures
+   |
+help: replace with an appropriate return type
+   |
+LL - fn foo() -> _ {
+LL + fn foo() -> impl Future<Output = i32> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/suggest-return-future.rs:15:13
    |
 LL | fn bar() -> _ {
-   |             ^
-   |             |
-   |             not allowed in type signatures
-   |             help: replace with an appropriate return type: `impl Future<Output = i32>`
+   |             ^ not allowed in type signatures
+   |
+help: replace with an appropriate return type
+   |
+LL - fn bar() -> _ {
+LL + fn bar() -> impl Future<Output = i32> {
+   |
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr b/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
index 8bb72833e30..77a637c470c 100644
--- a/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
+++ b/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
@@ -14,6 +14,11 @@ note: due to a current limitation of the type system, this implies a `'static` l
    |
 LL |     for<'a> I::Item<'a>: Debug,
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/hrtb-implied-1.rs:26:26
+   |
+LL |     for<'a> I::Item<'a>: Debug,
+   |                          ^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/impl-trait/precise-capturing/migration-note.rs b/tests/ui/impl-trait/precise-capturing/migration-note.rs
index 7587e89409a..412d8af9884 100644
--- a/tests/ui/impl-trait/precise-capturing/migration-note.rs
+++ b/tests/ui/impl-trait/precise-capturing/migration-note.rs
@@ -32,6 +32,7 @@ fn needs_static() {
     //~| NOTE borrowed value does not live long enoug
 
     fn needs_static(_: impl Sized + 'static) {}
+    //~^ NOTE requirement that the value outlives `'static` introduced here
     needs_static(a);
     //~^ NOTE argument requires that `x` is borrowed for `'static`
 }
@@ -79,6 +80,7 @@ fn needs_static_mut() {
     //~| NOTE borrowed value does not live long enough
 
     fn needs_static(_: impl Sized + 'static) {}
+    //~^ NOTE requirement that the value outlives `'static` introduced here
     needs_static(a);
     //~^ NOTE argument requires that `x` is borrowed for `'static`
 }
diff --git a/tests/ui/impl-trait/precise-capturing/migration-note.stderr b/tests/ui/impl-trait/precise-capturing/migration-note.stderr
index aa0f6400091..880e7878477 100644
--- a/tests/ui/impl-trait/precise-capturing/migration-note.stderr
+++ b/tests/ui/impl-trait/precise-capturing/migration-note.stderr
@@ -1,5 +1,5 @@
 error[E0597]: `x` does not live long enough
-  --> $DIR/migration-note.rs:182:17
+  --> $DIR/migration-note.rs:184:17
    |
 LL |     let x = vec![0];
    |         - binding `x` declared here
@@ -50,6 +50,11 @@ LL |
 LL | }
    | - `x` dropped here while still borrowed
    |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/migration-note.rs:34:37
+   |
+LL |     fn needs_static(_: impl Sized + 'static) {}
+   |                                     ^^^^^^^
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/migration-note.rs:29:13
    |
@@ -61,7 +66,7 @@ LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
    |                                               ++++++++
 
 error[E0505]: cannot move out of `x` because it is borrowed
-  --> $DIR/migration-note.rs:48:8
+  --> $DIR/migration-note.rs:49:8
    |
 LL |     let x = vec![1];
    |         - binding `x` declared here
@@ -76,7 +81,7 @@ LL | }
    | - borrow might be used here, when `a` is dropped and runs the destructor for type `impl std::fmt::Display`
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:43:13
+  --> $DIR/migration-note.rs:44:13
    |
 LL |     let a = display_len(&x);
    |             ^^^^^^^^^^^^^^^
@@ -90,7 +95,7 @@ LL |     let a = display_len(&x.clone());
    |                           ++++++++
 
 error[E0499]: cannot borrow `x` as mutable more than once at a time
-  --> $DIR/migration-note.rs:66:5
+  --> $DIR/migration-note.rs:67:5
    |
 LL |     let a = display_len_mut(&mut x);
    |                             ------ first mutable borrow occurs here
@@ -102,7 +107,7 @@ LL |     println!("{a}");
    |                - first borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:63:13
+  --> $DIR/migration-note.rs:64:13
    |
 LL |     let a = display_len_mut(&mut x);
    |             ^^^^^^^^^^^^^^^^^^^^^^^
@@ -112,7 +117,7 @@ LL | fn display_len_mut<T>(x: &mut Vec<T>) -> impl Display + use<T> {
    |                                                       ++++++++
 
 error[E0597]: `x` does not live long enough
-  --> $DIR/migration-note.rs:76:29
+  --> $DIR/migration-note.rs:77:29
    |
 LL |     let mut x = vec![1];
    |         ----- binding `x` declared here
@@ -126,8 +131,13 @@ LL |
 LL | }
    | - `x` dropped here while still borrowed
    |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/migration-note.rs:82:37
+   |
+LL |     fn needs_static(_: impl Sized + 'static) {}
+   |                                     ^^^^^^^
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:76:13
+  --> $DIR/migration-note.rs:77:13
    |
 LL |     let a = display_len_mut(&mut x);
    |             ^^^^^^^^^^^^^^^^^^^^^^^
@@ -137,7 +147,7 @@ LL | fn display_len_mut<T>(x: &mut Vec<T>) -> impl Display + use<T> {
    |                                                       ++++++++
 
 error[E0505]: cannot move out of `x` because it is borrowed
-  --> $DIR/migration-note.rs:95:8
+  --> $DIR/migration-note.rs:97:8
    |
 LL |     let mut x = vec![1];
    |         ----- binding `x` declared here
@@ -152,7 +162,7 @@ LL | }
    | - borrow might be used here, when `a` is dropped and runs the destructor for type `impl std::fmt::Display`
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:90:13
+  --> $DIR/migration-note.rs:92:13
    |
 LL |     let a = display_len_mut(&mut x);
    |             ^^^^^^^^^^^^^^^^^^^^^^^
@@ -166,7 +176,7 @@ LL |     let a = display_len_mut(&mut x.clone());
    |                                   ++++++++
 
 error[E0506]: cannot assign to `s.f` because it is borrowed
-  --> $DIR/migration-note.rs:115:5
+  --> $DIR/migration-note.rs:117:5
    |
 LL |     let a = display_field(&s.f);
    |                           ---- `s.f` is borrowed here
@@ -178,7 +188,7 @@ LL |     println!("{a}");
    |                - borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:112:13
+  --> $DIR/migration-note.rs:114:13
    |
 LL |     let a = display_field(&s.f);
    |             ^^^^^^^^^^^^^^^^^^^
@@ -188,7 +198,7 @@ LL | fn display_field<T: Copy + Display>(t: &T) -> impl Display + use<T> {
    |                                                            ++++++++
 
 error[E0506]: cannot assign to `s.f` because it is borrowed
-  --> $DIR/migration-note.rs:131:5
+  --> $DIR/migration-note.rs:133:5
    |
 LL |     let a = display_field(&mut s.f);
    |                           -------- `s.f` is borrowed here
@@ -200,7 +210,7 @@ LL |     println!("{a}");
    |                - borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:128:13
+  --> $DIR/migration-note.rs:130:13
    |
 LL |     let a = display_field(&mut s.f);
    |             ^^^^^^^^^^^^^^^^^^^^^^^
@@ -210,7 +220,7 @@ LL | fn display_field<T: Copy + Display>(t: &T) -> impl Display + use<T> {
    |                                                            ++++++++
 
 error[E0503]: cannot use `s.f` because it was mutably borrowed
-  --> $DIR/migration-note.rs:143:5
+  --> $DIR/migration-note.rs:145:5
    |
 LL |     let a = display_field(&mut s.f);
    |                           -------- `s.f` is borrowed here
@@ -222,7 +232,7 @@ LL |     println!("{a}");
    |                - borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:140:13
+  --> $DIR/migration-note.rs:142:13
    |
 LL |     let a = display_field(&mut s.f);
    |             ^^^^^^^^^^^^^^^^^^^^^^^
@@ -232,7 +242,7 @@ LL | fn display_field<T: Copy + Display>(t: &T) -> impl Display + use<T> {
    |                                                            ++++++++
 
 error[E0597]: `z.f` does not live long enough
-  --> $DIR/migration-note.rs:159:25
+  --> $DIR/migration-note.rs:161:25
    |
 LL |         let z = Z { f: vec![1] };
    |             - binding `z` declared here
@@ -248,7 +258,7 @@ LL | }
    |
    = note: values in a scope are dropped in the opposite order they are defined
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:159:13
+  --> $DIR/migration-note.rs:161:13
    |
 LL |         x = display_len(&z.f);
    |             ^^^^^^^^^^^^^^^^^
@@ -258,7 +268,7 @@ LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
    |                                               ++++++++
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/migration-note.rs:170:40
+  --> $DIR/migration-note.rs:172:40
    |
 LL |     let x = { let x = display_len(&mut vec![0]); x };
    |                                        ^^^^^^^ - - borrow later used here
@@ -268,7 +278,7 @@ LL |     let x = { let x = display_len(&mut vec![0]); x };
    |
    = note: consider using a `let` binding to create a longer lived value
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:170:23
+  --> $DIR/migration-note.rs:172:23
    |
 LL |     let x = { let x = display_len(&mut vec![0]); x };
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -279,7 +289,7 @@ LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
    |                                               ++++++++
 
 error[E0505]: cannot move out of `x` because it is borrowed
-  --> $DIR/migration-note.rs:198:10
+  --> $DIR/migration-note.rs:200:10
    |
 LL |     let x = String::new();
    |         - binding `x` declared here
@@ -294,12 +304,12 @@ LL | }
    | - borrow might be used here, when `y` is dropped and runs the destructor for type `impl Sized`
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
-  --> $DIR/migration-note.rs:195:13
+  --> $DIR/migration-note.rs:197:13
    |
 LL |     let y = capture_apit(&x);
    |             ^^^^^^^^^^^^^^^^
 note: you could use a `use<...>` bound to explicitly specify captures, but argument-position `impl Trait`s are not nameable
-  --> $DIR/migration-note.rs:189:21
+  --> $DIR/migration-note.rs:191:21
    |
 LL | fn capture_apit(x: &impl Sized) -> impl Sized {}
    |                     ^^^^^^^^^^
diff --git a/tests/ui/inference/need_type_info/issue-107745-avoid-expr-from-macro-expansion.stderr b/tests/ui/inference/need_type_info/issue-107745-avoid-expr-from-macro-expansion.stderr
index a78941f9e11..3de317d2af6 100644
--- a/tests/ui/inference/need_type_info/issue-107745-avoid-expr-from-macro-expansion.stderr
+++ b/tests/ui/inference/need_type_info/issue-107745-avoid-expr-from-macro-expansion.stderr
@@ -1,10 +1,10 @@
 error[E0282]: type annotations needed
-  --> $DIR/issue-107745-avoid-expr-from-macro-expansion.rs:17:5
+  --> $DIR/issue-107745-avoid-expr-from-macro-expansion.rs:17:22
    |
 LL |     println!("{:?}", []);
-   |     ^^^^^^^^^^^^^^^^^^^^ cannot infer type
+   |                      ^^ cannot infer type
    |
-   = note: this error originates in the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
index e13653f3423..af07745a00a 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
@@ -69,6 +69,12 @@ LL |         cell_x.set(cell_a.get()); // forces 'a: 'x, implies 'a = 'static ->
 LL |     })
 LL | }
    | - `a` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/propagate-approximated-shorter-to-static-comparing-against-free.rs:13:8
+   |
+LL |     F: for<'x> FnOnce(Cell<&'a u32>, Cell<&'x u32>),
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/nll/closure-requirements/propagate-multiple-requirements.stderr b/tests/ui/nll/closure-requirements/propagate-multiple-requirements.stderr
index 15f48d88c37..4136ac418de 100644
--- a/tests/ui/nll/closure-requirements/propagate-multiple-requirements.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-multiple-requirements.stderr
@@ -13,6 +13,12 @@ LL |         z = &local_arr;
 ...
 LL | }
    | - `local_arr` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/propagate-multiple-requirements.rs:4:21
+   |
+LL | fn once<S, T, U, F: FnOnce(S, T) -> U>(f: F, s: S, t: T) -> U {
+   |                     ^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/nll/local-outlives-static-via-hrtb.stderr b/tests/ui/nll/local-outlives-static-via-hrtb.stderr
index a98f11ce513..263d271b6b3 100644
--- a/tests/ui/nll/local-outlives-static-via-hrtb.stderr
+++ b/tests/ui/nll/local-outlives-static-via-hrtb.stderr
@@ -17,6 +17,11 @@ note: due to a current limitation of the type system, this implies a `'static` l
    |
 LL | fn assert_static_via_hrtb<G>(_: G) where for<'a> G: Outlives<'a> {}
    |                                          ^^^^^^^^^^^^^^^^^^^^^^^
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/local-outlives-static-via-hrtb.rs:15:53
+   |
+LL | fn assert_static_via_hrtb<G>(_: G) where for<'a> G: Outlives<'a> {}
+   |                                                     ^^^^^^^^^^^^
 
 error[E0597]: `local` does not live long enough
   --> $DIR/local-outlives-static-via-hrtb.rs:25:45
@@ -37,6 +42,11 @@ note: due to a current limitation of the type system, this implies a `'static` l
    |
 LL |     for<'a> &'a T: Reference<AssociatedType = &'a ()>,
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/local-outlives-static-via-hrtb.rs:19:30
+   |
+LL |     for<'a> &'a T: Reference<AssociatedType = &'a ()>,
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.nll.stderr b/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.nll.stderr
index 6e47b8e59f5..804b3f00a26 100644
--- a/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.nll.stderr
+++ b/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.nll.stderr
@@ -18,6 +18,11 @@ note: due to a current limitation of the type system, this implies a `'static` l
    |
 LL | fn bad<F: Fn(&()) -> &()>(_: F) {}
    |           ^^^^^^^^^^^^^^
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/location-insensitive-scopes-issue-117146.rs:20:22
+   |
+LL | fn bad<F: Fn(&()) -> &()>(_: F) {}
+   |                      ^^^
 
 error: implementation of `Fn` is not general enough
   --> $DIR/location-insensitive-scopes-issue-117146.rs:13:5
diff --git a/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.polonius.stderr b/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.polonius.stderr
index 6e47b8e59f5..804b3f00a26 100644
--- a/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.polonius.stderr
+++ b/tests/ui/nll/polonius/location-insensitive-scopes-issue-117146.polonius.stderr
@@ -18,6 +18,11 @@ note: due to a current limitation of the type system, this implies a `'static` l
    |
 LL | fn bad<F: Fn(&()) -> &()>(_: F) {}
    |           ^^^^^^^^^^^^^^
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/location-insensitive-scopes-issue-117146.rs:20:22
+   |
+LL | fn bad<F: Fn(&()) -> &()>(_: F) {}
+   |                      ^^^
 
 error: implementation of `Fn` is not general enough
   --> $DIR/location-insensitive-scopes-issue-117146.rs:13:5
diff --git a/tests/ui/regions/multiple-sources-for-outlives-requirement.rs b/tests/ui/regions/multiple-sources-for-outlives-requirement.rs
new file mode 100644
index 00000000000..720cd1cf6ee
--- /dev/null
+++ b/tests/ui/regions/multiple-sources-for-outlives-requirement.rs
@@ -0,0 +1,11 @@
+fn outlives_indir<'a: 'b, 'b, T: 'a>(_x: T) {}
+//~^ NOTE: requirements that the value outlives `'b` introduced here
+
+fn foo<'b>() { //~ NOTE: lifetime `'b` defined here
+    outlives_indir::<'_, 'b, _>(&mut 1u32); //~ ERROR: temporary value dropped while borrowed
+    //~^ NOTE: argument requires that borrow lasts for `'b`
+    //~| NOTE: creates a temporary value which is freed while still in use
+    //~| NOTE: temporary value is freed at the end of this statement
+}
+
+fn main() {}
diff --git a/tests/ui/regions/multiple-sources-for-outlives-requirement.stderr b/tests/ui/regions/multiple-sources-for-outlives-requirement.stderr
new file mode 100644
index 00000000000..4cdaf950e15
--- /dev/null
+++ b/tests/ui/regions/multiple-sources-for-outlives-requirement.stderr
@@ -0,0 +1,20 @@
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/multiple-sources-for-outlives-requirement.rs:5:38
+   |
+LL | fn foo<'b>() {
+   |        -- lifetime `'b` defined here
+LL |     outlives_indir::<'_, 'b, _>(&mut 1u32);
+   |     ---------------------------------^^^^-- temporary value is freed at the end of this statement
+   |     |                                |
+   |     |                                creates a temporary value which is freed while still in use
+   |     argument requires that borrow lasts for `'b`
+   |
+note: requirements that the value outlives `'b` introduced here
+  --> $DIR/multiple-sources-for-outlives-requirement.rs:1:23
+   |
+LL | fn outlives_indir<'a: 'b, 'b, T: 'a>(_x: T) {}
+   |                       ^^         ^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0716`.
diff --git a/tests/ui/regions/regions-infer-proc-static-upvar.stderr b/tests/ui/regions/regions-infer-proc-static-upvar.stderr
index 919fcffdc53..158d74ed06d 100644
--- a/tests/ui/regions/regions-infer-proc-static-upvar.stderr
+++ b/tests/ui/regions/regions-infer-proc-static-upvar.stderr
@@ -11,6 +11,12 @@ LL | |     });
    | |______- argument requires that `x` is borrowed for `'static`
 LL |   }
    |   - `x` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/regions-infer-proc-static-upvar.rs:4:19
+   |
+LL | fn foo<F:FnOnce()+'static>(_p: F) { }
+   |                   ^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/regions/regions-pattern-typing-issue-19552.stderr b/tests/ui/regions/regions-pattern-typing-issue-19552.stderr
index 1d3d5e831c3..a8fd827bc69 100644
--- a/tests/ui/regions/regions-pattern-typing-issue-19552.stderr
+++ b/tests/ui/regions/regions-pattern-typing-issue-19552.stderr
@@ -10,6 +10,12 @@ LL |         [ word ] => { assert_static(word); }
 LL |     }
 LL | }
    | - `line` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/regions-pattern-typing-issue-19552.rs:1:21
+   |
+LL | fn assert_static<T: 'static>(_t: T) {}
+   |                     ^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/return/infer-return-ty-for-fn-sig-issue-125488.stderr b/tests/ui/return/infer-return-ty-for-fn-sig-issue-125488.stderr
index 8b7c5e1681a..839e4265e03 100644
--- a/tests/ui/return/infer-return-ty-for-fn-sig-issue-125488.stderr
+++ b/tests/ui/return/infer-return-ty-for-fn-sig-issue-125488.stderr
@@ -2,37 +2,49 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/infer-return-ty-for-fn-sig-issue-125488.rs:8:24
    |
 LL |     fn f1(s: S<'_>) -> _ {
-   |                        ^
-   |                        |
-   |                        not allowed in type signatures
-   |                        help: replace with the correct return type: `S<'_>`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn f1(s: S<'_>) -> _ {
+LL +     fn f1(s: S<'_>) -> S<'_> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/infer-return-ty-for-fn-sig-issue-125488.rs:13:24
    |
 LL |     fn f2(s: S<'_>) -> _ {
-   |                        ^
-   |                        |
-   |                        not allowed in type signatures
-   |                        help: replace with the correct return type: `S<'_>`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn f2(s: S<'_>) -> _ {
+LL +     fn f2(s: S<'_>) -> S<'_> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/infer-return-ty-for-fn-sig-issue-125488.rs:23:24
    |
 LL |     fn f3(s: S<'_>) -> _ {
-   |                        ^
-   |                        |
-   |                        not allowed in type signatures
-   |                        help: replace with the correct return type: `S<'_>`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn f3(s: S<'_>) -> _ {
+LL +     fn f3(s: S<'_>) -> S<'_> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/infer-return-ty-for-fn-sig-issue-125488.rs:28:24
    |
 LL |     fn f4(s: S<'_>) -> _ {
-   |                        ^
-   |                        |
-   |                        not allowed in type signatures
-   |                        help: replace with the correct return type: `S<'_>`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn f4(s: S<'_>) -> _ {
+LL +     fn f4(s: S<'_>) -> S<'_> {
+   |
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/static/static-lifetime-bound.stderr b/tests/ui/static/static-lifetime-bound.stderr
index 8b0d3a0bf4c..51be79be5db 100644
--- a/tests/ui/static/static-lifetime-bound.stderr
+++ b/tests/ui/static/static-lifetime-bound.stderr
@@ -10,6 +10,12 @@ LL |     f(&x);
    |     argument requires that `x` is borrowed for `'static`
 LL | }
    | - `x` dropped here while still borrowed
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/static-lifetime-bound.rs:1:10
+   |
+LL | fn f<'a: 'static>(_: &'a i32) {}
+   |          ^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/static/static-region-bound.stderr b/tests/ui/static/static-region-bound.stderr
index a47c9457102..8472738daa4 100644
--- a/tests/ui/static/static-region-bound.stderr
+++ b/tests/ui/static/static-region-bound.stderr
@@ -7,6 +7,12 @@ LL |     f(x);
    |     ---- argument requires that borrow lasts for `'static`
 LL | }
    | - temporary value is freed at the end of this statement
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/static-region-bound.rs:3:8
+   |
+LL | fn f<T:'static>(_: T) {}
+   |        ^^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/suggestions/return-cycle-2.stderr b/tests/ui/suggestions/return-cycle-2.stderr
index 23de2309e87..e852cd34a72 100644
--- a/tests/ui/suggestions/return-cycle-2.stderr
+++ b/tests/ui/suggestions/return-cycle-2.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/return-cycle-2.rs:6:34
    |
 LL |     fn as_ref(_: i32, _: i32) -> _ {
-   |                                  ^
-   |                                  |
-   |                                  not allowed in type signatures
-   |                                  help: replace with the correct return type: `Token<&'static T>`
+   |                                  ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn as_ref(_: i32, _: i32) -> _ {
+LL +     fn as_ref(_: i32, _: i32) -> Token<&'static T> {
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/suggestions/return-cycle.stderr b/tests/ui/suggestions/return-cycle.stderr
index 60470490441..cd46c2daa40 100644
--- a/tests/ui/suggestions/return-cycle.stderr
+++ b/tests/ui/suggestions/return-cycle.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/return-cycle.rs:6:17
    |
 LL |     fn new() -> _ {
-   |                 ^
-   |                 |
-   |                 not allowed in type signatures
-   |                 help: replace with the correct return type: `Token<()>`
+   |                 ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn new() -> _ {
+LL +     fn new() -> Token<()> {
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/suggestions/suggest-fn-ptr-for-fn-item-in-fn-ret.stderr b/tests/ui/suggestions/suggest-fn-ptr-for-fn-item-in-fn-ret.stderr
index bf7790e2307..9880dd95d86 100644
--- a/tests/ui/suggestions/suggest-fn-ptr-for-fn-item-in-fn-ret.stderr
+++ b/tests/ui/suggestions/suggest-fn-ptr-for-fn-item-in-fn-ret.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/suggest-fn-ptr-for-fn-item-in-fn-ret.rs:7:13
    |
 LL | fn bar() -> _ { Wrapper(foo) }
-   |             ^
-   |             |
-   |             not allowed in type signatures
-   |             help: replace with the correct return type: `Wrapper<fn()>`
+   |             ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn bar() -> _ { Wrapper(foo) }
+LL + fn bar() -> Wrapper<fn()> { Wrapper(foo) }
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-1.rs b/tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-1.rs
new file mode 100644
index 00000000000..e35e48dfcec
--- /dev/null
+++ b/tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-1.rs
@@ -0,0 +1,25 @@
+//@ ignore-compare-mode-next-solver
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+// Regression test for trait-system-refactor-initiative#220. Builtin `Fn`-trait
+// candidates required `for<'latebound> Output<'latebound>: Sized` which ended
+// up resulting in overflow if the return type is an opaque in the defining scope.
+//
+// We now eagerly instantiate the binder of the function definition which avoids
+// that overflow by relating the lifetime of the opaque to something from the
+// input.
+fn flat_map<T, F, I, G>(_: F, _: G)
+where
+    F: FnOnce(T) -> I,
+    I: Iterator,
+    G: Fn(<I as Iterator>::Item) -> usize,
+{
+}
+
+fn rarw<'a>(_: &'a ()) -> impl Iterator<Item = &'a str> {
+    flat_map(rarw, |x| x.len());
+    std::iter::empty()
+}
+
+fn main() {}
diff --git a/tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-2.rs b/tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-2.rs
new file mode 100644
index 00000000000..1d64e422d89
--- /dev/null
+++ b/tests/ui/traits/next-solver/opaques/overflow-hr-fn-trait-sized-2.rs
@@ -0,0 +1,14 @@
+//@ ignore-compare-mode-next-solver
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+// Regression test for trait-system-refactor-initiative#204, see
+// the sibling test for more details.
+
+fn constrain<'a, F: FnOnce(&'a ())>(_: F) {}
+fn foo<'a>(_: &'a ()) -> impl Sized + use<'a> {
+    constrain(foo);
+    ()
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/issue-77179.stderr b/tests/ui/type-alias-impl-trait/issue-77179.stderr
index c0f197ec48c..222edfb90a7 100644
--- a/tests/ui/type-alias-impl-trait/issue-77179.stderr
+++ b/tests/ui/type-alias-impl-trait/issue-77179.stderr
@@ -11,10 +11,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/issue-77179.rs:8:22
    |
 LL | fn test() -> Pointer<_> {
-   |              --------^-
-   |              |       |
-   |              |       not allowed in type signatures
-   |              help: replace with the correct return type: `Pointer<i32>`
+   |                      ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn test() -> Pointer<_> {
+LL + fn test() -> Pointer<i32> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for functions
   --> $DIR/issue-77179.rs:19:25
diff --git a/tests/ui/typeck/issue-80779.stderr b/tests/ui/typeck/issue-80779.stderr
index 2261ba61654..90c80fa2ea6 100644
--- a/tests/ui/typeck/issue-80779.stderr
+++ b/tests/ui/typeck/issue-80779.stderr
@@ -2,19 +2,25 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/issue-80779.rs:10:28
    |
 LL | pub fn g(_: T<'static>) -> _ {}
-   |                            ^
-   |                            |
-   |                            not allowed in type signatures
-   |                            help: replace with the correct return type: `()`
+   |                            ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - pub fn g(_: T<'static>) -> _ {}
+LL + pub fn g(_: T<'static>) -> () {}
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/issue-80779.rs:5:29
    |
 LL | pub fn f<'a>(val: T<'a>) -> _ {
-   |                             ^
-   |                             |
-   |                             not allowed in type signatures
-   |                             help: replace with the correct return type: `()`
+   |                             ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - pub fn f<'a>(val: T<'a>) -> _ {
+LL + pub fn f<'a>(val: T<'a>) -> () {
+   |
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/typeck/issue-98260.stderr b/tests/ui/typeck/issue-98260.stderr
index b7debd335b0..f380db55cdf 100644
--- a/tests/ui/typeck/issue-98260.stderr
+++ b/tests/ui/typeck/issue-98260.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/issue-98260.rs:3:27
    |
 LL |     fn a(aa: B) -> Result<_, B> {
-   |                    -------^----
-   |                    |      |
-   |                    |      not allowed in type signatures
-   |                    help: replace with the correct return type: `Result<(), B>`
+   |                           ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn a(aa: B) -> Result<_, B> {
+LL +     fn a(aa: B) -> Result<(), B> {
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/typeck/typeck_type_placeholder_item.stderr b/tests/ui/typeck/typeck_type_placeholder_item.stderr
index 87750ee6dc1..240dc1ae8ab 100644
--- a/tests/ui/typeck/typeck_type_placeholder_item.stderr
+++ b/tests/ui/typeck/typeck_type_placeholder_item.stderr
@@ -48,20 +48,27 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:7:14
    |
 LL | fn test() -> _ { 5 }
-   |              ^
-   |              |
-   |              not allowed in type signatures
-   |              help: replace with the correct return type: `i32`
+   |              ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn test() -> _ { 5 }
+LL + fn test() -> i32 { 5 }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/typeck_type_placeholder_item.rs:10:16
    |
 LL | fn test2() -> (_, _) { (5, 5) }
-   |               -^--^-
-   |               ||  |
-   |               ||  not allowed in type signatures
-   |               |not allowed in type signatures
-   |               help: replace with the correct return type: `(i32, i32)`
+   |                ^  ^ not allowed in type signatures
+   |                |
+   |                not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn test2() -> (_, _) { (5, 5) }
+LL + fn test2() -> (i32, i32) { (5, 5) }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static variables
   --> $DIR/typeck_type_placeholder_item.rs:13:15
@@ -189,19 +196,25 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:47:26
    |
 LL | fn test11(x: &usize) -> &_ {
-   |                         -^
-   |                         ||
-   |                         |not allowed in type signatures
-   |                         help: replace with the correct return type: `&&usize`
+   |                          ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn test11(x: &usize) -> &_ {
+LL + fn test11(x: &usize) -> &&usize {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/typeck_type_placeholder_item.rs:52:52
    |
 LL | unsafe fn test12(x: *const usize) -> *const *const _ {
-   |                                      --------------^
-   |                                      |             |
-   |                                      |             not allowed in type signatures
-   |                                      help: replace with the correct return type: `*const *const usize`
+   |                                                    ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - unsafe fn test12(x: *const usize) -> *const *const _ {
+LL + unsafe fn test12(x: *const usize) -> *const *const usize {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for methods
   --> $DIR/typeck_type_placeholder_item.rs:58:24
@@ -261,20 +274,27 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:80:21
    |
 LL |     fn fn_test() -> _ { 5 }
-   |                     ^
-   |                     |
-   |                     not allowed in type signatures
-   |                     help: replace with the correct return type: `i32`
+   |                     ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn fn_test() -> _ { 5 }
+LL +     fn fn_test() -> i32 { 5 }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/typeck_type_placeholder_item.rs:83:23
    |
 LL |     fn fn_test2() -> (_, _) { (5, 5) }
-   |                      -^--^-
-   |                      ||  |
-   |                      ||  not allowed in type signatures
-   |                      |not allowed in type signatures
-   |                      help: replace with the correct return type: `(i32, i32)`
+   |                       ^  ^ not allowed in type signatures
+   |                       |
+   |                       not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn fn_test2() -> (_, _) { (5, 5) }
+LL +     fn fn_test2() -> (i32, i32) { (5, 5) }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static variables
   --> $DIR/typeck_type_placeholder_item.rs:86:22
@@ -374,20 +394,27 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:134:30
    |
 LL |     fn fn_test12(x: i32) -> (_, _) { (x, x) }
-   |                             -^--^-
-   |                             ||  |
-   |                             ||  not allowed in type signatures
-   |                             |not allowed in type signatures
-   |                             help: replace with the correct return type: `(i32, i32)`
+   |                              ^  ^ not allowed in type signatures
+   |                              |
+   |                              not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn fn_test12(x: i32) -> (_, _) { (x, x) }
+LL +     fn fn_test12(x: i32) -> (i32, i32) { (x, x) }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
   --> $DIR/typeck_type_placeholder_item.rs:137:33
    |
 LL |     fn fn_test13(x: _) -> (i32, _) { (x, x) }
-   |                           ------^-
-   |                           |     |
-   |                           |     not allowed in type signatures
-   |                           help: replace with the correct return type: `(i32, i32)`
+   |                                 ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn fn_test13(x: _) -> (i32, _) { (x, x) }
+LL +     fn fn_test13(x: _) -> (i32, i32) { (x, x) }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for methods
   --> $DIR/typeck_type_placeholder_item.rs:142:31
@@ -528,10 +555,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:226:31
    |
 LL | fn value() -> Option<&'static _> {
-   |               ----------------^-
-   |               |               |
-   |               |               not allowed in type signatures
-   |               help: replace with the correct return type: `Option<&'static u8>`
+   |                               ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn value() -> Option<&'static _> {
+LL + fn value() -> Option<&'static u8> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
   --> $DIR/typeck_type_placeholder_item.rs:231:17
@@ -549,10 +579,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:235:31
    |
 LL | fn evens_squared(n: usize) -> _ {
-   |                               ^
-   |                               |
-   |                               not allowed in type signatures
-   |                               help: replace with an appropriate return type: `impl Iterator<Item = usize>`
+   |                               ^ not allowed in type signatures
+   |
+help: replace with an appropriate return type
+   |
+LL - fn evens_squared(n: usize) -> _ {
+LL + fn evens_squared(n: usize) -> impl Iterator<Item = usize> {
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
   --> $DIR/typeck_type_placeholder_item.rs:240:10
@@ -570,10 +603,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:40:24
    |
 LL |     fn test9(&self) -> _ { () }
-   |                        ^
-   |                        |
-   |                        not allowed in type signatures
-   |                        help: replace with the correct return type: `()`
+   |                        ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -     fn test9(&self) -> _ { () }
+LL +     fn test9(&self) -> () { () }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for methods
   --> $DIR/typeck_type_placeholder_item.rs:43:27
@@ -585,10 +621,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item.rs:107:31
    |
 LL |         fn fn_test9(&self) -> _ { () }
-   |                               ^
-   |                               |
-   |                               not allowed in type signatures
-   |                               help: replace with the correct return type: `()`
+   |                               ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL -         fn fn_test9(&self) -> _ { () }
+LL +         fn fn_test9(&self) -> () { () }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for methods
   --> $DIR/typeck_type_placeholder_item.rs:110:34
diff --git a/tests/ui/typeck/typeck_type_placeholder_item_help.stderr b/tests/ui/typeck/typeck_type_placeholder_item_help.stderr
index 2fce00e7a8e..3f21ff6d4ec 100644
--- a/tests/ui/typeck/typeck_type_placeholder_item_help.stderr
+++ b/tests/ui/typeck/typeck_type_placeholder_item_help.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/typeck_type_placeholder_item_help.rs:4:15
    |
 LL | fn test1() -> _ { Some(42) }
-   |               ^
-   |               |
-   |               not allowed in type signatures
-   |               help: replace with the correct return type: `Option<i32>`
+   |               ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - fn test1() -> _ { Some(42) }
+LL + fn test1() -> Option<i32> { Some(42) }
+   |
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants
   --> $DIR/typeck_type_placeholder_item_help.rs:7:14
diff --git a/tests/ui/variance/leaking-unnameables.stderr b/tests/ui/variance/leaking-unnameables.stderr
index 92afe952801..59bdc33040d 100644
--- a/tests/ui/variance/leaking-unnameables.stderr
+++ b/tests/ui/variance/leaking-unnameables.stderr
@@ -2,10 +2,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures
   --> $DIR/leaking-unnameables.rs:8:18
    |
 LL | pub fn f<T>() -> _ {
-   |                  ^
-   |                  |
-   |                  not allowed in type signatures
-   |                  help: replace with the correct return type: `fn()`
+   |                  ^ not allowed in type signatures
+   |
+help: replace with the correct return type
+   |
+LL - pub fn f<T>() -> _ {
+LL + pub fn f<T>() -> fn() {
+   |
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/wf/wf-in-where-clause-static.current.stderr b/tests/ui/wf/wf-in-where-clause-static.current.stderr
index d0bb89884c6..788fe2c3faa 100644
--- a/tests/ui/wf/wf-in-where-clause-static.current.stderr
+++ b/tests/ui/wf/wf-in-where-clause-static.current.stderr
@@ -6,6 +6,12 @@ LL |     let s = foo(&String::from("blah blah blah"));
    |             |    |
    |             |    creates a temporary value which is freed while still in use
    |             argument requires that borrow lasts for `'static`
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/wf-in-where-clause-static.rs:12:17
+   |
+LL |     &'static S: Static,
+   |                 ^^^^^^
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/wf/wf-in-where-clause-static.next.stderr b/tests/ui/wf/wf-in-where-clause-static.next.stderr
index d0bb89884c6..788fe2c3faa 100644
--- a/tests/ui/wf/wf-in-where-clause-static.next.stderr
+++ b/tests/ui/wf/wf-in-where-clause-static.next.stderr
@@ -6,6 +6,12 @@ LL |     let s = foo(&String::from("blah blah blah"));
    |             |    |
    |             |    creates a temporary value which is freed while still in use
    |             argument requires that borrow lasts for `'static`
+   |
+note: requirement that the value outlives `'static` introduced here
+  --> $DIR/wf-in-where-clause-static.rs:12:17
+   |
+LL |     &'static S: Static,
+   |                 ^^^^^^
 
 error: aborting due to 1 previous error