Auto merge of #126996 - oli-obk:do_not_count_errors, r=nnethercote

Automatically taint InferCtxt when errors are emitted

r? `@nnethercote`

Basically `InferCtxt::dcx` now returns a `DiagCtxt` that refers back to the `Cell<Option<ErrorGuaranteed>>` of the `InferCtxt` and thus when invoking `Diag::emit`, and the diagnostic is an error, we taint the `InferCtxt` directly.

That change on its own has no effect at all, because `InferCtxt` already tracks whether errors have been emitted by recording the global error count when it gets opened, and checking at the end whether the count changed. So I removed that error count check, which had a bit of fallout that I immediately fixed by invoking `InferCtxt::dcx` instead of `TyCtxt::dcx` in a bunch of places.

The remaining new errors are because an error was reported in another query, and never bubbled up. I think they are minor enough for this to be ok, and sometimes it actually improves diagnostics, by not silencing useful diagnostics anymore.

fixes #126485 (cc `@olafes)`

There are more improvements we can do (like tainting in hir ty lowering), but I would rather do that in follow up PRs, because it requires some refactorings.

compiler/rustc_borrowck/src/borrowck_errors.rs

@@ -6,8 +6,8 @@ use rustc_middle::span_bug;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::Span;
 
-impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'infcx, 'tcx> crate::MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
-    pub fn dcx(&self) -> DiagCtxtHandle<'tcx> {
+    pub fn dcx(&self) -> DiagCtxtHandle<'infcx> {
         self.infcx.dcx()
     }
 
@@ -18,7 +18,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         place: &str,
         borrow_place: &str,
         value_place: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         self.dcx().create_err(crate::session_diagnostics::MoveBorrow {
             place,
             span,
@@ -34,7 +34,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         desc: &str,
         borrow_span: Span,
         borrow_desc: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             span,
@@ -54,7 +54,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         old_loan_span: Span,
         old_opt_via: &str,
         old_load_end_span: Option<Span>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let via = |msg: &str| if msg.is_empty() { "".to_string() } else { format!(" (via {msg})") };
         let mut err = struct_span_code_err!(
             self.dcx(),
@@ -101,7 +101,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         desc: &str,
         old_loan_span: Span,
         old_load_end_span: Option<Span>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let mut err = struct_span_code_err!(
             self.dcx(),
             new_loan_span,
@@ -134,7 +134,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         noun_old: &str,
         old_opt_via: &str,
         previous_end_span: Option<Span>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let mut err = struct_span_code_err!(
             self.dcx(),
             new_loan_span,
@@ -166,7 +166,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         old_opt_via: &str,
         previous_end_span: Option<Span>,
         second_borrow_desc: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let mut err = struct_span_code_err!(
             self.dcx(),
             new_loan_span,
@@ -198,7 +198,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         kind_old: &str,
         msg_old: &str,
         old_load_end_span: Option<Span>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let via = |msg: &str| if msg.is_empty() { "".to_string() } else { format!(" (via {msg})") };
         let mut err = struct_span_code_err!(
             self.dcx(),
@@ -239,7 +239,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         span: Span,
         borrow_span: Span,
         desc: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             span,
@@ -256,12 +256,12 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         span: Span,
         desc: &str,
         is_arg: bool,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let msg = if is_arg { "to immutable argument" } else { "twice to immutable variable" };
         struct_span_code_err!(self.dcx(), span, E0384, "cannot assign {} {}", msg, desc)
     }
 
-    pub(crate) fn cannot_assign(&self, span: Span, desc: &str) -> Diag<'tcx> {
+    pub(crate) fn cannot_assign(&self, span: Span, desc: &str) -> Diag<'infcx> {
         struct_span_code_err!(self.dcx(), span, E0594, "cannot assign to {}", desc)
     }
 
@@ -269,7 +269,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         &self,
         move_from_span: Span,
         move_from_desc: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             move_from_span,
@@ -287,7 +287,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         move_from_span: Span,
         ty: Ty<'_>,
         is_index: Option<bool>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let type_name = match (&ty.kind(), is_index) {
             (&ty::Array(_, _), Some(true)) | (&ty::Array(_, _), None) => "array",
             (&ty::Slice(_), _) => "slice",
@@ -308,7 +308,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         &self,
         move_from_span: Span,
         container_ty: Ty<'_>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             move_from_span,
@@ -325,7 +325,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         verb: &str,
         optional_adverb_for_moved: &str,
         moved_path: Option<String>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let moved_path = moved_path.map(|mp| format!(": `{mp}`")).unwrap_or_default();
 
         struct_span_code_err!(
@@ -344,7 +344,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         span: Span,
         path: &str,
         reason: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             span,
@@ -362,7 +362,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         immutable_place: &str,
         immutable_section: &str,
         action: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             mutate_span,
@@ -380,7 +380,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         &self,
         span: Span,
         yield_span: Span,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let coroutine_kind = self.body.coroutine.as_ref().unwrap().coroutine_kind;
         struct_span_code_err!(
             self.dcx(),
@@ -391,7 +391,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         .with_span_label(yield_span, "possible yield occurs here")
     }
 
-    pub(crate) fn cannot_borrow_across_destructor(&self, borrow_span: Span) -> Diag<'tcx> {
+    pub(crate) fn cannot_borrow_across_destructor(&self, borrow_span: Span) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             borrow_span,
@@ -400,7 +400,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         )
     }
 
-    pub(crate) fn path_does_not_live_long_enough(&self, span: Span, path: &str) -> Diag<'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,)
     }
 
@@ -410,7 +410,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         return_kind: &str,
         reference_desc: &str,
         path_desc: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             span,
@@ -433,7 +433,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         borrowed_path: &str,
         capture_span: Span,
         scope: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             closure_span,
@@ -445,7 +445,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         .with_span_label(closure_span, format!("may outlive borrowed value {borrowed_path}"))
     }
 
-    pub(crate) fn thread_local_value_does_not_live_long_enough(&self, span: Span) -> Diag<'tcx> {
+    pub(crate) fn thread_local_value_does_not_live_long_enough(&self, span: Span) -> Diag<'infcx> {
         struct_span_code_err!(
             self.dcx(),
             span,
@@ -454,7 +454,7 @@ impl<'tcx> crate::MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         )
     }
 
-    pub(crate) fn temporary_value_borrowed_for_too_long(&self, span: Span) -> Diag<'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",)
     }
 }

compiler/rustc_borrowck/src/dataflow.rs

@@ -15,24 +15,24 @@ use std::fmt;
 use crate::{places_conflict, BorrowSet, PlaceConflictBias, PlaceExt, RegionInferenceContext};
 
 /// The results of the dataflow analyses used by the borrow checker.
-pub struct BorrowckResults<'mir, 'tcx> {
+pub struct BorrowckResults<'a, 'mir, 'tcx> {
-    pub(crate) borrows: Results<'tcx, Borrows<'mir, 'tcx>>,
+    pub(crate) borrows: Results<'tcx, Borrows<'a, 'mir, 'tcx>>,
-    pub(crate) uninits: Results<'tcx, MaybeUninitializedPlaces<'mir, 'tcx>>,
+    pub(crate) uninits: Results<'tcx, MaybeUninitializedPlaces<'a, 'mir, 'tcx>>,
-    pub(crate) ever_inits: Results<'tcx, EverInitializedPlaces<'mir, 'tcx>>,
+    pub(crate) ever_inits: Results<'tcx, EverInitializedPlaces<'a, 'mir, 'tcx>>,
 }
 
 /// The transient state of the dataflow analyses used by the borrow checker.
 #[derive(Debug)]
-pub struct BorrowckFlowState<'mir, 'tcx> {
+pub struct BorrowckFlowState<'a, 'mir, 'tcx> {
-    pub(crate) borrows: <Borrows<'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) borrows: <Borrows<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
-    pub(crate) uninits: <MaybeUninitializedPlaces<'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) uninits: <MaybeUninitializedPlaces<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
-    pub(crate) ever_inits: <EverInitializedPlaces<'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) ever_inits: <EverInitializedPlaces<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
 }
 
-impl<'mir, 'tcx> ResultsVisitable<'tcx> for BorrowckResults<'mir, 'tcx> {
+impl<'a, 'mir, 'tcx> ResultsVisitable<'tcx> for BorrowckResults<'a, 'mir, 'tcx> {
     // All three analyses are forward, but we have to use just one here.
-    type Direction = <Borrows<'mir, 'tcx> as AnalysisDomain<'tcx>>::Direction;
+    type Direction = <Borrows<'a, 'mir, 'tcx> as AnalysisDomain<'tcx>>::Direction;
-    type FlowState = BorrowckFlowState<'mir, 'tcx>;
+    type FlowState = BorrowckFlowState<'a, 'mir, 'tcx>;
 
     fn new_flow_state(&self, body: &mir::Body<'tcx>) -> Self::FlowState {
         BorrowckFlowState {
@@ -106,11 +106,11 @@ rustc_index::newtype_index! {
 /// `BorrowIndex`, and maps each such index to a `BorrowData`
 /// describing the borrow. These indexes are used for representing the
 /// borrows in compact bitvectors.
-pub struct Borrows<'mir, 'tcx> {
+pub struct Borrows<'a, 'mir, 'tcx> {
     tcx: TyCtxt<'tcx>,
     body: &'mir Body<'tcx>,
 
-    borrow_set: &'mir BorrowSet<'tcx>,
+    borrow_set: &'a BorrowSet<'tcx>,
     borrows_out_of_scope_at_location: FxIndexMap<Location, Vec<BorrowIndex>>,
 }
 
@@ -389,12 +389,12 @@ impl<'tcx> PoloniusOutOfScopePrecomputer<'_, 'tcx> {
     }
 }
 
-impl<'mir, 'tcx> Borrows<'mir, 'tcx> {
+impl<'a, 'mir, 'tcx> Borrows<'a, 'mir, 'tcx> {
     pub fn new(
         tcx: TyCtxt<'tcx>,
         body: &'mir Body<'tcx>,
-        regioncx: &'mir RegionInferenceContext<'tcx>,
+        regioncx: &RegionInferenceContext<'tcx>,
-        borrow_set: &'mir BorrowSet<'tcx>,
+        borrow_set: &'a BorrowSet<'tcx>,
     ) -> Self {
         let mut borrows_out_of_scope_at_location =
             calculate_borrows_out_of_scope_at_location(body, regioncx, borrow_set);
@@ -494,7 +494,7 @@ impl<'mir, 'tcx> Borrows<'mir, 'tcx> {
     }
 }
 
-impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, 'tcx> {
+impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, '_, 'tcx> {
     type Domain = BitSet<BorrowIndex>;
 
     const NAME: &'static str = "borrows";
@@ -517,7 +517,7 @@ impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, 'tcx> {
 ///   region stops containing the CFG points reachable from the issuing location.
 /// - we also kill loans of conflicting places when overwriting a shared path: e.g. borrows of
 ///   `a.b.c` when `a` is overwritten.
-impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, 'tcx> {
+impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, '_, 'tcx> {
     type Idx = BorrowIndex;
 
     fn domain_size(&self, _: &mir::Body<'tcx>) -> usize {
@@ -617,8 +617,8 @@ impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, 'tcx> {
     }
 }
 
-impl DebugWithContext<Borrows<'_, '_>> for BorrowIndex {
+impl DebugWithContext<Borrows<'_, '_, '_>> for BorrowIndex {
-    fn fmt_with(&self, ctxt: &Borrows<'_, '_>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    fn fmt_with(&self, ctxt: &Borrows<'_, '_, '_>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", ctxt.location(*self))
     }
 }

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -149,13 +149,13 @@ trait TypeOpInfo<'tcx> {
 
     fn base_universe(&self) -> ty::UniverseIndex;
 
-    fn nice_error(
+    fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<Diag<'tcx>>;
+    ) -> Option<Diag<'infcx>>;
 
     #[instrument(level = "debug", skip(self, mbcx))]
     fn report_error(
@@ -231,18 +231,25 @@ impl<'tcx> TypeOpInfo<'tcx> for PredicateQuery<'tcx> {
         self.base_universe
     }
 
-    fn nice_error(
+    fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Option<Diag<'infcx>> {
         let (infcx, key, _) =
             mbcx.infcx.tcx.infer_ctxt().build_with_canonical(cause.span, &self.canonical_query);
         let ocx = ObligationCtxt::new(&infcx);
         type_op_prove_predicate_with_cause(&ocx, key, cause);
-        try_extract_error_from_fulfill_cx(&ocx, mbcx.mir_def_id(), placeholder_region, error_region)
+        let diag = try_extract_error_from_fulfill_cx(
+            &ocx,
+            mbcx.mir_def_id(),
+            placeholder_region,
+            error_region,
+        )?
+        .with_dcx(mbcx.dcx());
+        Some(diag)
     }
 }
 
@@ -268,13 +275,13 @@ where
         self.base_universe
     }
 
-    fn nice_error(
+    fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Option<Diag<'infcx>> {
         let (infcx, key, _) =
             mbcx.infcx.tcx.infer_ctxt().build_with_canonical(cause.span, &self.canonical_query);
         let ocx = ObligationCtxt::new(&infcx);
@@ -288,7 +295,14 @@ where
         let (param_env, value) = key.into_parts();
         let _ = ocx.normalize(&cause, param_env, value.value);
 
-        try_extract_error_from_fulfill_cx(&ocx, mbcx.mir_def_id(), placeholder_region, error_region)
+        let diag = try_extract_error_from_fulfill_cx(
+            &ocx,
+            mbcx.mir_def_id(),
+            placeholder_region,
+            error_region,
+        )?
+        .with_dcx(mbcx.dcx());
+        Some(diag)
     }
 }
 
@@ -308,18 +322,25 @@ impl<'tcx> TypeOpInfo<'tcx> for AscribeUserTypeQuery<'tcx> {
         self.base_universe
     }
 
-    fn nice_error(
+    fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
         cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Option<Diag<'infcx>> {
         let (infcx, key, _) =
             mbcx.infcx.tcx.infer_ctxt().build_with_canonical(cause.span, &self.canonical_query);
         let ocx = ObligationCtxt::new(&infcx);
         type_op_ascribe_user_type_with_span(&ocx, key, Some(cause.span)).ok()?;
-        try_extract_error_from_fulfill_cx(&ocx, mbcx.mir_def_id(), placeholder_region, error_region)
+        let diag = try_extract_error_from_fulfill_cx(
+            &ocx,
+            mbcx.mir_def_id(),
+            placeholder_region,
+            error_region,
+        )?
+        .with_dcx(mbcx.dcx());
+        Some(diag)
     }
 }
 
@@ -334,13 +355,13 @@ impl<'tcx> TypeOpInfo<'tcx> for crate::type_check::InstantiateOpaqueType<'tcx> {
         self.base_universe.unwrap()
     }
 
-    fn nice_error(
+    fn nice_error<'infcx>(
         &self,
-        mbcx: &mut MirBorrowckCtxt<'_, '_, '_, 'tcx>,
+        mbcx: &mut MirBorrowckCtxt<'_, '_, 'infcx, 'tcx>,
         _cause: ObligationCause<'tcx>,
         placeholder_region: ty::Region<'tcx>,
         error_region: Option<ty::Region<'tcx>>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Option<Diag<'infcx>> {
         try_extract_error_from_region_constraints(
             mbcx.infcx,
             mbcx.mir_def_id(),
@@ -358,12 +379,12 @@ impl<'tcx> TypeOpInfo<'tcx> for crate::type_check::InstantiateOpaqueType<'tcx> {
 }
 
 #[instrument(skip(ocx), level = "debug")]
-fn try_extract_error_from_fulfill_cx<'tcx>(
+fn try_extract_error_from_fulfill_cx<'a, 'tcx>(
-    ocx: &ObligationCtxt<'_, 'tcx>,
+    ocx: &ObligationCtxt<'a, 'tcx>,
     generic_param_scope: LocalDefId,
     placeholder_region: ty::Region<'tcx>,
     error_region: Option<ty::Region<'tcx>>,
-) -> Option<Diag<'tcx>> {
+) -> Option<Diag<'a>> {
     // We generally shouldn't have errors here because the query was
     // already run, but there's no point using `span_delayed_bug`
     // when we're going to emit an error here anyway.
@@ -381,15 +402,15 @@ fn try_extract_error_from_fulfill_cx<'tcx>(
 }
 
 #[instrument(level = "debug", skip(infcx, region_var_origin, universe_of_region))]
-fn try_extract_error_from_region_constraints<'tcx>(
+fn try_extract_error_from_region_constraints<'a, 'tcx>(
-    infcx: &InferCtxt<'tcx>,
+    infcx: &'a InferCtxt<'tcx>,
     generic_param_scope: LocalDefId,
     placeholder_region: ty::Region<'tcx>,
     error_region: Option<ty::Region<'tcx>>,
     region_constraints: &RegionConstraintData<'tcx>,
     mut region_var_origin: impl FnMut(RegionVid) -> RegionVariableOrigin,
     mut universe_of_region: impl FnMut(RegionVid) -> UniverseIndex,
-) -> Option<Diag<'tcx>> {
+) -> Option<Diag<'a>> {
     let placeholder_universe = match placeholder_region.kind() {
         ty::RePlaceholder(p) => p.universe,
         ty::ReVar(vid) => universe_of_region(vid),

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -73,7 +73,7 @@ enum StorageDeadOrDrop<'tcx> {
     Destructor(Ty<'tcx>),
 }
 
-impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
     pub(crate) fn report_use_of_moved_or_uninitialized(
         &mut self,
         location: Location,
@@ -341,7 +341,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
     fn suggest_ref_or_clone(
         &self,
         mpi: MovePathIndex,
-        err: &mut Diag<'tcx>,
+        err: &mut Diag<'infcx>,
         in_pattern: &mut bool,
         move_spans: UseSpans<'tcx>,
     ) {
@@ -517,7 +517,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         desired_action: InitializationRequiringAction,
         span: Span,
         use_spans: UseSpans<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         // We need all statements in the body where the binding was assigned to later find all
         // the branching code paths where the binding *wasn't* assigned to.
         let inits = &self.move_data.init_path_map[mpi];
@@ -1461,7 +1461,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         location: Location,
         (place, _span): (Place<'tcx>, Span),
         borrow: &BorrowData<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let borrow_spans = self.retrieve_borrow_spans(borrow);
         let borrow_span = borrow_spans.args_or_use();
 
@@ -1511,7 +1511,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         (place, span): (Place<'tcx>, Span),
         gen_borrow_kind: BorrowKind,
         issued_borrow: &BorrowData<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let issued_spans = self.retrieve_borrow_spans(issued_borrow);
         let issued_span = issued_spans.args_or_use();
 
@@ -1802,7 +1802,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         err
     }
 
-    fn suggest_copy_for_type_in_cloned_ref(&self, err: &mut Diag<'tcx>, place: Place<'tcx>) {
+    fn suggest_copy_for_type_in_cloned_ref(&self, err: &mut Diag<'infcx>, place: Place<'tcx>) {
         let tcx = self.infcx.tcx;
         let hir = tcx.hir();
         let Some(body_id) = tcx.hir_node(self.mir_hir_id()).body_id() else { return };
@@ -2861,7 +2861,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         drop_span: Span,
         borrow_spans: UseSpans<'tcx>,
         explanation: BorrowExplanation<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         debug!(
             "report_local_value_does_not_live_long_enough(\
              {:?}, {:?}, {:?}, {:?}, {:?}\
@@ -3036,7 +3036,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         &self,
         drop_span: Span,
         borrow_span: Span,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         debug!(
             "report_thread_local_value_does_not_live_long_enough(\
              {:?}, {:?}\
@@ -3061,7 +3061,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         borrow_spans: UseSpans<'tcx>,
         proper_span: Span,
         explanation: BorrowExplanation<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         if let BorrowExplanation::MustBeValidFor { category, span, from_closure: false, .. } =
             explanation
         {
@@ -3226,7 +3226,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         return_span: Span,
         category: ConstraintCategory<'tcx>,
         opt_place_desc: Option<&String>,
-    ) -> Result<(), Diag<'tcx>> {
+    ) -> Result<(), Diag<'infcx>> {
         let return_kind = match category {
             ConstraintCategory::Return(_) => "return",
             ConstraintCategory::Yield => "yield",
@@ -3319,7 +3319,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         constraint_span: Span,
         captured_var: &str,
         scope: &str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let tcx = self.infcx.tcx;
         let args_span = use_span.args_or_use();
 
@@ -3431,7 +3431,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         upvar_span: Span,
         upvar_name: Symbol,
         escape_span: Span,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let tcx = self.infcx.tcx;
 
         let escapes_from = tcx.def_descr(self.mir_def_id().to_def_id());

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -69,7 +69,7 @@ pub(super) struct DescribePlaceOpt {
 
 pub(super) struct IncludingTupleField(pub(super) bool);
 
-impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
     /// Adds a suggestion when a closure is invoked twice with a moved variable or when a closure
     /// is moved after being invoked.
     ///
@@ -86,7 +86,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         &self,
         location: Location,
         place: PlaceRef<'tcx>,
-        diag: &mut Diag<'_>,
+        diag: &mut Diag<'infcx>,
     ) -> bool {
         debug!("add_moved_or_invoked_closure_note: location={:?} place={:?}", location, place);
         let mut target = place.local_or_deref_local();

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -93,7 +93,7 @@ enum GroupedMoveError<'tcx> {
     },
 }
 
-impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
     pub(crate) fn report_move_errors(&mut self) {
         let grouped_errors = self.group_move_errors();
         for error in grouped_errors {
@@ -291,7 +291,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         self.buffer_error(err);
     }
 
-    fn report_cannot_move_from_static(&mut self, place: Place<'tcx>, span: Span) -> Diag<'tcx> {
+    fn report_cannot_move_from_static(&mut self, place: Place<'tcx>, span: Span) -> Diag<'infcx> {
         let description = if place.projection.len() == 1 {
             format!("static item {}", self.describe_any_place(place.as_ref()))
         } else {
@@ -428,7 +428,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         deref_target_place: Place<'tcx>,
         span: Span,
         use_spans: Option<UseSpans<'tcx>>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let tcx = self.infcx.tcx;
         // Inspect the type of the content behind the
         // borrow to provide feedback about why this

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -30,7 +30,7 @@ pub(crate) enum AccessKind {
     Mutate,
 }
 
-impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
     pub(crate) fn report_mutability_error(
         &mut self,
         access_place: Place<'tcx>,
@@ -541,7 +541,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
     }
 
     /// Suggest `map[k] = v` => `map.insert(k, v)` and the like.
-    fn suggest_map_index_mut_alternatives(&self, ty: Ty<'tcx>, err: &mut Diag<'tcx>, span: Span) {
+    fn suggest_map_index_mut_alternatives(&self, ty: Ty<'tcx>, err: &mut Diag<'infcx>, span: Span) {
         let Some(adt) = ty.ty_adt_def() else { return };
         let did = adt.did();
         if self.infcx.tcx.is_diagnostic_item(sym::HashMap, did)
@@ -550,13 +550,13 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
             /// Walks through the HIR, looking for the corresponding span for this error.
             /// When it finds it, see if it corresponds to assignment operator whose LHS
             /// is an index expr.
-            struct SuggestIndexOperatorAlternativeVisitor<'a, 'tcx> {
+            struct SuggestIndexOperatorAlternativeVisitor<'a, 'infcx, 'tcx> {
                 assign_span: Span,
-                err: &'a mut Diag<'tcx>,
+                err: &'a mut Diag<'infcx>,
                 ty: Ty<'tcx>,
                 suggested: bool,
             }
-            impl<'a, 'tcx> Visitor<'tcx> for SuggestIndexOperatorAlternativeVisitor<'a, 'tcx> {
+            impl<'a, 'cx, 'tcx> Visitor<'tcx> for SuggestIndexOperatorAlternativeVisitor<'a, 'cx, 'tcx> {
                 fn visit_stmt(&mut self, stmt: &'tcx hir::Stmt<'tcx>) {
                     hir::intravisit::walk_stmt(self, stmt);
                     let expr = match stmt.kind {

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -160,7 +160,7 @@ pub struct ErrorConstraintInfo<'tcx> {
     pub(super) span: Span,
 }
 
-impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
     /// Converts a region inference variable into a `ty::Region` that
     /// we can use for error reporting. If `r` is universally bound,
     /// then we use the name that we have on record for it. If `r` is
@@ -360,7 +360,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
                     let named_key = self.regioncx.name_regions(self.infcx.tcx, key);
                     let named_region = self.regioncx.name_regions(self.infcx.tcx, member_region);
                     let diag = unexpected_hidden_region_diagnostic(
-                        self.infcx.tcx,
+                        self.infcx,
                         self.mir_def_id(),
                         span,
                         named_ty,
@@ -589,7 +589,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
         &self,
         errci: &ErrorConstraintInfo<'tcx>,
         kind: ReturnConstraint,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'infcx> {
         let ErrorConstraintInfo { outlived_fr, span, .. } = errci;
 
         let mut output_ty = self.regioncx.universal_regions().unnormalized_output_ty;
@@ -658,7 +658,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
     ///    |     ^^^^^^^^^^ `x` escapes the function body here
     /// ```
     #[instrument(level = "debug", skip(self))]
-    fn report_escaping_data_error(&self, errci: &ErrorConstraintInfo<'tcx>) -> Diag<'tcx> {
+    fn report_escaping_data_error(&self, errci: &ErrorConstraintInfo<'tcx>) -> Diag<'infcx> {
         let ErrorConstraintInfo { span, category, .. } = errci;
 
         let fr_name_and_span = self.regioncx.get_var_name_and_span_for_region(
@@ -767,7 +767,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
     ///    |                    is returning data with lifetime `'b`
     /// ```
     #[allow(rustc::diagnostic_outside_of_impl)] // FIXME
-    fn report_general_error(&self, errci: &ErrorConstraintInfo<'tcx>) -> Diag<'tcx> {
+    fn report_general_error(&self, errci: &ErrorConstraintInfo<'tcx>) -> Diag<'infcx> {
         let ErrorConstraintInfo {
             fr,
             fr_is_local,

compiler/rustc_borrowck/src/lib.rs

@@ -310,8 +310,8 @@ fn do_mir_borrowck<'tcx>(
         promoted_mbcx.report_move_errors();
         diags = promoted_mbcx.diags;
 
-        struct MoveVisitor<'a, 'b, 'mir, 'cx, 'tcx> {
+        struct MoveVisitor<'a, 'b, 'mir, 'infcx, 'tcx> {
-            ctxt: &'a mut MirBorrowckCtxt<'b, 'mir, 'cx, 'tcx>,
+            ctxt: &'a mut MirBorrowckCtxt<'b, 'mir, 'infcx, 'tcx>,
         }
 
         impl<'tcx> Visitor<'tcx> for MoveVisitor<'_, '_, '_, '_, 'tcx> {
@@ -528,8 +528,8 @@ impl<'tcx> Deref for BorrowckInferCtxt<'tcx> {
     }
 }
 
-struct MirBorrowckCtxt<'a, 'mir, 'cx, 'tcx> {
+struct MirBorrowckCtxt<'a, 'mir, 'infcx, 'tcx> {
-    infcx: &'cx BorrowckInferCtxt<'tcx>,
+    infcx: &'infcx BorrowckInferCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
     body: &'mir Body<'tcx>,
     move_data: &'a MoveData<'tcx>,
@@ -596,7 +596,7 @@ struct MirBorrowckCtxt<'a, 'mir, 'cx, 'tcx> {
     /// Results of Polonius analysis.
     polonius_output: Option<Rc<PoloniusOutput>>,
 
-    diags: diags::BorrowckDiags<'tcx>,
+    diags: diags::BorrowckDiags<'infcx, 'tcx>,
     move_errors: Vec<MoveError<'tcx>>,
 }
 
@@ -605,15 +605,15 @@ struct MirBorrowckCtxt<'a, 'mir, 'cx, 'tcx> {
 // 2. loans made in overlapping scopes do not conflict
 // 3. assignments do not affect things loaned out as immutable
 // 4. moves do not affect things loaned out in any way
-impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
+impl<'a, 'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
-    for MirBorrowckCtxt<'_, 'mir, '_, 'tcx>
+    for MirBorrowckCtxt<'a, 'mir, '_, 'tcx>
 {
-    type FlowState = Flows<'mir, 'tcx>;
+    type FlowState = Flows<'a, 'mir, 'tcx>;
 
     fn visit_statement_before_primary_effect(
         &mut self,
         _results: &mut R,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
         stmt: &'mir Statement<'tcx>,
         location: Location,
     ) {
@@ -683,7 +683,7 @@ impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
     fn visit_terminator_before_primary_effect(
         &mut self,
         _results: &mut R,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
         term: &'mir Terminator<'tcx>,
         loc: Location,
     ) {
@@ -794,7 +794,7 @@ impl<'mir, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'mir, 'tcx, R>
     fn visit_terminator_after_primary_effect(
         &mut self,
         _results: &mut R,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
         term: &'mir Terminator<'tcx>,
         loc: Location,
     ) {
@@ -988,7 +988,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         place_span: (Place<'tcx>, Span),
         kind: (AccessDepth, ReadOrWrite),
         is_local_mutation_allowed: LocalMutationIsAllowed,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         let (sd, rw) = kind;
 
@@ -1038,7 +1038,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         place_span: (Place<'tcx>, Span),
         sd: AccessDepth,
         rw: ReadOrWrite,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) -> bool {
         let mut error_reported = false;
         let borrow_set = Rc::clone(&self.borrow_set);
@@ -1179,7 +1179,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         location: Location,
         place_span: (Place<'tcx>, Span),
         kind: AccessDepth,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         // Write of P[i] or *P requires P init'd.
         self.check_if_assigned_path_is_moved(location, place_span, flow_state);
@@ -1197,7 +1197,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         &mut self,
         location: Location,
         (rvalue, span): (&'mir Rvalue<'tcx>, Span),
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         match rvalue {
             &Rvalue::Ref(_ /*rgn*/, bk, place) => {
@@ -1455,7 +1455,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         &mut self,
         location: Location,
         (operand, span): (&'mir Operand<'tcx>, Span),
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         match *operand {
             Operand::Copy(place) => {
@@ -1579,7 +1579,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         &mut self,
         location: Location,
         span: Span,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         // Two-phase borrow support: For each activation that is newly
         // generated at this statement, check if it interferes with
@@ -1743,7 +1743,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         location: Location,
         desired_action: InitializationRequiringAction,
         place_span: (PlaceRef<'tcx>, Span),
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         let maybe_uninits = &flow_state.uninits;
 
@@ -1848,7 +1848,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         location: Location,
         desired_action: InitializationRequiringAction,
         place_span: (PlaceRef<'tcx>, Span),
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         let maybe_uninits = &flow_state.uninits;
 
@@ -1947,7 +1947,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         &mut self,
         location: Location,
         (place, span): (Place<'tcx>, Span),
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) {
         debug!("check_if_assigned_path_is_moved place: {:?}", place);
 
@@ -2013,7 +2013,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
             location: Location,
             base: PlaceRef<'tcx>,
             span: Span,
-            flow_state: &Flows<'mir, 'tcx>,
+            flow_state: &Flows<'_, 'mir, 'tcx>,
         ) {
             // rust-lang/rust#21232: Until Rust allows reads from the
             // initialized parts of partially initialized structs, we
@@ -2104,7 +2104,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
         (place, span): (Place<'tcx>, Span),
         kind: ReadOrWrite,
         is_local_mutation_allowed: LocalMutationIsAllowed,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
         location: Location,
     ) -> bool {
         debug!(
@@ -2220,7 +2220,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
     fn is_local_ever_initialized(
         &self,
         local: Local,
-        flow_state: &Flows<'mir, 'tcx>,
+        flow_state: &Flows<'_, 'mir, 'tcx>,
     ) -> Option<InitIndex> {
         let mpi = self.move_data.rev_lookup.find_local(local)?;
         let ii = &self.move_data.init_path_map[mpi];
@@ -2228,7 +2228,7 @@ impl<'mir, 'tcx> MirBorrowckCtxt<'_, 'mir, '_, 'tcx> {
     }
 
     /// Adds the place into the used mutable variables set
-    fn add_used_mut(&mut self, root_place: RootPlace<'tcx>, flow_state: &Flows<'mir, 'tcx>) {
+    fn add_used_mut(&mut self, root_place: RootPlace<'tcx>, flow_state: &Flows<'_, 'mir, 'tcx>) {
         match root_place {
             RootPlace { place_local: local, place_projection: [], is_local_mutation_allowed } => {
                 // If the local may have been initialized, and it is now currently being
@@ -2428,12 +2428,12 @@ mod diags {
 
     use super::*;
 
-    enum BufferedDiag<'tcx> {
+    enum BufferedDiag<'infcx> {
-        Error(Diag<'tcx>),
+        Error(Diag<'infcx>),
-        NonError(Diag<'tcx, ()>),
+        NonError(Diag<'infcx, ()>),
     }
 
-    impl<'tcx> BufferedDiag<'tcx> {
+    impl<'infcx> BufferedDiag<'infcx> {
         fn sort_span(&self) -> Span {
             match self {
                 BufferedDiag::Error(diag) => diag.sort_span,
@@ -2442,7 +2442,7 @@ mod diags {
         }
     }
 
-    pub struct BorrowckDiags<'tcx> {
+    pub struct BorrowckDiags<'infcx, 'tcx> {
         /// This field keeps track of move errors that are to be reported for given move indices.
         ///
         /// There are situations where many errors can be reported for a single move out (see
@@ -2457,15 +2457,15 @@ mod diags {
         /// `BTreeMap` is used to preserve the order of insertions when iterating. This is necessary
         /// when errors in the map are being re-added to the error buffer so that errors with the
         /// same primary span come out in a consistent order.
-        buffered_move_errors: BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, Diag<'tcx>)>,
+        buffered_move_errors: BTreeMap<Vec<MoveOutIndex>, (PlaceRef<'tcx>, Diag<'infcx>)>,
 
-        buffered_mut_errors: FxIndexMap<Span, (Diag<'tcx>, usize)>,
+        buffered_mut_errors: FxIndexMap<Span, (Diag<'infcx>, usize)>,
 
         /// Buffer of diagnostics to be reported. A mixture of error and non-error diagnostics.
-        buffered_diags: Vec<BufferedDiag<'tcx>>,
+        buffered_diags: Vec<BufferedDiag<'infcx>>,
     }
 
-    impl<'tcx> BorrowckDiags<'tcx> {
+    impl<'infcx, 'tcx> BorrowckDiags<'infcx, 'tcx> {
         pub fn new() -> Self {
             BorrowckDiags {
                 buffered_move_errors: BTreeMap::new(),
@@ -2474,28 +2474,28 @@ mod diags {
             }
         }
 
-        pub fn buffer_error(&mut self, diag: Diag<'tcx>) {
+        pub fn buffer_error(&mut self, diag: Diag<'infcx>) {
             self.buffered_diags.push(BufferedDiag::Error(diag));
         }
 
-        pub fn buffer_non_error(&mut self, diag: Diag<'tcx, ()>) {
+        pub fn buffer_non_error(&mut self, diag: Diag<'infcx, ()>) {
             self.buffered_diags.push(BufferedDiag::NonError(diag));
         }
     }
 
-    impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
+    impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
-        pub fn buffer_error(&mut self, diag: Diag<'tcx>) {
+        pub fn buffer_error(&mut self, diag: Diag<'infcx>) {
             self.diags.buffer_error(diag);
         }
 
-        pub fn buffer_non_error(&mut self, diag: Diag<'tcx, ()>) {
+        pub fn buffer_non_error(&mut self, diag: Diag<'infcx, ()>) {
             self.diags.buffer_non_error(diag);
         }
 
         pub fn buffer_move_error(
             &mut self,
             move_out_indices: Vec<MoveOutIndex>,
-            place_and_err: (PlaceRef<'tcx>, Diag<'tcx>),
+            place_and_err: (PlaceRef<'tcx>, Diag<'infcx>),
         ) -> bool {
             if let Some((_, diag)) =
                 self.diags.buffered_move_errors.insert(move_out_indices, place_and_err)
@@ -2508,12 +2508,12 @@ mod diags {
             }
         }
 
-        pub fn get_buffered_mut_error(&mut self, span: Span) -> Option<(Diag<'tcx>, usize)> {
+        pub fn get_buffered_mut_error(&mut self, span: Span) -> Option<(Diag<'infcx>, usize)> {
             // FIXME(#120456) - is `swap_remove` correct?
             self.diags.buffered_mut_errors.swap_remove(&span)
         }
 
-        pub fn buffer_mut_error(&mut self, span: Span, diag: Diag<'tcx>, count: usize) {
+        pub fn buffer_mut_error(&mut self, span: Span, diag: Diag<'infcx>, count: usize) {
             self.diags.buffered_mut_errors.insert(span, (diag, count));
         }
 
@@ -2554,7 +2554,7 @@ mod diags {
         pub fn has_move_error(
             &self,
             move_out_indices: &[MoveOutIndex],
-        ) -> Option<&(PlaceRef<'tcx>, Diag<'tcx>)> {
+        ) -> Option<&(PlaceRef<'tcx>, Diag<'infcx>)> {
             self.diags.buffered_move_errors.get(move_out_indices)
         }
     }

compiler/rustc_borrowck/src/nll.rs

@@ -81,7 +81,7 @@ pub(crate) fn compute_regions<'cx, 'tcx>(
     promoted: &IndexSlice<Promoted, Body<'tcx>>,
     location_table: &LocationTable,
     param_env: ty::ParamEnv<'tcx>,
-    flow_inits: &mut ResultsCursor<'cx, 'tcx, MaybeInitializedPlaces<'cx, 'tcx>>,
+    flow_inits: &mut ResultsCursor<'cx, 'tcx, MaybeInitializedPlaces<'_, 'cx, 'tcx>>,
     move_data: &MoveData<'tcx>,
     borrow_set: &BorrowSet<'tcx>,
     upvars: &[&ty::CapturedPlace<'tcx>],
@@ -262,13 +262,13 @@ pub(super) fn dump_mir_results<'tcx>(
 
 #[allow(rustc::diagnostic_outside_of_impl)]
 #[allow(rustc::untranslatable_diagnostic)]
-pub(super) fn dump_annotation<'tcx>(
+pub(super) fn dump_annotation<'tcx, 'cx>(
-    infcx: &BorrowckInferCtxt<'tcx>,
+    infcx: &'cx BorrowckInferCtxt<'tcx>,
     body: &Body<'tcx>,
     regioncx: &RegionInferenceContext<'tcx>,
     closure_region_requirements: &Option<ClosureRegionRequirements<'tcx>>,
     opaque_type_values: &FxIndexMap<LocalDefId, OpaqueHiddenType<'tcx>>,
-    diags: &mut crate::diags::BorrowckDiags<'tcx>,
+    diags: &mut crate::diags::BorrowckDiags<'cx, 'tcx>,
 ) {
     let tcx = infcx.tcx;
     let base_def_id = tcx.typeck_root_def_id(body.source.def_id());
@@ -285,7 +285,7 @@ pub(super) fn dump_annotation<'tcx>(
 
     let def_span = tcx.def_span(body.source.def_id());
     let mut err = if let Some(closure_region_requirements) = closure_region_requirements {
-        let mut err = tcx.dcx().struct_span_note(def_span, "external requirements");
+        let mut err = infcx.dcx().struct_span_note(def_span, "external requirements");
 
         regioncx.annotate(tcx, &mut err);
 
@@ -304,7 +304,7 @@ pub(super) fn dump_annotation<'tcx>(
 
         err
     } else {
-        let mut err = tcx.dcx().struct_span_note(def_span, "no external requirements");
+        let mut err = infcx.dcx().struct_span_note(def_span, "no external requirements");
         regioncx.annotate(tcx, &mut err);
 
         err

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -285,7 +285,7 @@ impl<'tcx> InferCtxt<'tcx> {
         }
 
         if let Err(guar) =
-            check_opaque_type_parameter_valid(self.tcx, opaque_type_key, instantiated_ty.span)
+            check_opaque_type_parameter_valid(self, opaque_type_key, instantiated_ty.span)
         {
             return Ty::new_error(self.tcx, guar);
         }
@@ -294,6 +294,10 @@ impl<'tcx> InferCtxt<'tcx> {
             .remap_generic_params_to_declaration_params(opaque_type_key, self.tcx, false)
             .ty;
 
+        if let Err(e) = definition_ty.error_reported() {
+            return Ty::new_error(self.tcx, e);
+        }
+
         // `definition_ty` does not live in of the current inference context,
         // so lets make sure that we don't accidentally misuse our current `infcx`.
         match check_opaque_type_well_formed(
@@ -387,10 +391,11 @@ fn check_opaque_type_well_formed<'tcx>(
 /// [rustc-dev-guide chapter]:
 /// https://rustc-dev-guide.rust-lang.org/opaque-types-region-infer-restrictions.html
 fn check_opaque_type_parameter_valid<'tcx>(
-    tcx: TyCtxt<'tcx>,
+    infcx: &InferCtxt<'tcx>,
     opaque_type_key: OpaqueTypeKey<'tcx>,
     span: Span,
 ) -> Result<(), ErrorGuaranteed> {
+    let tcx = infcx.tcx;
     let opaque_generics = tcx.generics_of(opaque_type_key.def_id);
     let opaque_env = LazyOpaqueTyEnv::new(tcx, opaque_type_key.def_id);
     let mut seen_params: FxIndexMap<_, Vec<_>> = FxIndexMap::default();
@@ -420,7 +425,7 @@ fn check_opaque_type_parameter_valid<'tcx>(
 
             opaque_env.param_is_error(i)?;
 
-            return Err(tcx.dcx().emit_err(NonGenericOpaqueTypeParam {
+            return Err(infcx.dcx().emit_err(NonGenericOpaqueTypeParam {
                 ty: arg,
                 kind,
                 span,
@@ -438,7 +443,7 @@ fn check_opaque_type_parameter_valid<'tcx>(
                 .collect();
             #[allow(rustc::diagnostic_outside_of_impl)]
             #[allow(rustc::untranslatable_diagnostic)]
-            return Err(tcx
+            return Err(infcx
                 .dcx()
                 .struct_span_err(span, "non-defining opaque type use in defining scope")
                 .with_span_note(spans, format!("{descr} used multiple times"))

compiler/rustc_borrowck/src/type_check/liveness/mod.rs

@@ -34,7 +34,7 @@ pub(super) fn generate<'mir, 'tcx>(
     typeck: &mut TypeChecker<'_, 'tcx>,
     body: &Body<'tcx>,
     elements: &Rc<DenseLocationMap>,
-    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
+    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'_, 'mir, 'tcx>>,
     move_data: &MoveData<'tcx>,
 ) {
     debug!("liveness::generate");

compiler/rustc_borrowck/src/type_check/liveness/trace.rs

@@ -43,7 +43,7 @@ pub(super) fn trace<'mir, 'tcx>(
     typeck: &mut TypeChecker<'_, 'tcx>,
     body: &Body<'tcx>,
     elements: &Rc<DenseLocationMap>,
-    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
+    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'_, 'mir, 'tcx>>,
     move_data: &MoveData<'tcx>,
     relevant_live_locals: Vec<Local>,
     boring_locals: Vec<Local>,
@@ -101,7 +101,7 @@ pub(super) fn trace<'mir, 'tcx>(
 }
 
 /// Contextual state for the type-liveness coroutine.
-struct LivenessContext<'me, 'typeck, 'flow, 'tcx> {
+struct LivenessContext<'a, 'me, 'typeck, 'flow, 'tcx> {
     /// Current type-checker, giving us our inference context etc.
     typeck: &'me mut TypeChecker<'typeck, 'tcx>,
 
@@ -119,7 +119,7 @@ struct LivenessContext<'me, 'typeck, 'flow, 'tcx> {
 
     /// Results of dataflow tracking which variables (and paths) have been
     /// initialized.
-    flow_inits: &'me mut ResultsCursor<'flow, 'tcx, MaybeInitializedPlaces<'flow, 'tcx>>,
+    flow_inits: &'me mut ResultsCursor<'flow, 'tcx, MaybeInitializedPlaces<'a, 'flow, 'tcx>>,
 
     /// Index indicating where each variable is assigned, used, or
     /// dropped.
@@ -131,8 +131,8 @@ struct DropData<'tcx> {
     region_constraint_data: Option<&'tcx QueryRegionConstraints<'tcx>>,
 }
 
-struct LivenessResults<'me, 'typeck, 'flow, 'tcx> {
+struct LivenessResults<'a, 'me, 'typeck, 'flow, 'tcx> {
-    cx: LivenessContext<'me, 'typeck, 'flow, 'tcx>,
+    cx: LivenessContext<'a, 'me, 'typeck, 'flow, 'tcx>,
 
     /// Set of points that define the current local.
     defs: BitSet<PointIndex>,
@@ -153,8 +153,8 @@ struct LivenessResults<'me, 'typeck, 'flow, 'tcx> {
     stack: Vec<PointIndex>,
 }
 
-impl<'me, 'typeck, 'flow, 'tcx> LivenessResults<'me, 'typeck, 'flow, 'tcx> {
+impl<'a, 'me, 'typeck, 'flow, 'tcx> LivenessResults<'a, 'me, 'typeck, 'flow, 'tcx> {
-    fn new(cx: LivenessContext<'me, 'typeck, 'flow, 'tcx>) -> Self {
+    fn new(cx: LivenessContext<'a, 'me, 'typeck, 'flow, 'tcx>) -> Self {
         let num_points = cx.elements.num_points();
         LivenessResults {
             cx,
@@ -507,7 +507,7 @@ impl<'me, 'typeck, 'flow, 'tcx> LivenessResults<'me, 'typeck, 'flow, 'tcx> {
     }
 }
 
-impl<'tcx> LivenessContext<'_, '_, '_, 'tcx> {
+impl<'tcx> LivenessContext<'_, '_, '_, '_, 'tcx> {
     /// Returns `true` if the local variable (or some part of it) is initialized at the current
     /// cursor position. Callers should call one of the `seek` methods immediately before to point
     /// the cursor to the desired location.

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -129,7 +129,7 @@ pub(crate) fn type_check<'mir, 'tcx>(
     location_table: &LocationTable,
     borrow_set: &BorrowSet<'tcx>,
     all_facts: &mut Option<AllFacts>,
-    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
+    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'_, 'mir, 'tcx>>,
     move_data: &MoveData<'tcx>,
     elements: &Rc<DenseLocationMap>,
     upvars: &[&ty::CapturedPlace<'tcx>],

compiler/rustc_borrowck/src/used_muts.rs

@@ -45,10 +45,10 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, '_, 'tcx> {
 
 /// MIR visitor for collecting used mutable variables.
 /// The 'visit lifetime represents the duration of the MIR walk.
-struct GatherUsedMutsVisitor<'visit, 'a, 'mir, 'cx, 'tcx> {
+struct GatherUsedMutsVisitor<'visit, 'a, 'mir, 'infcx, 'tcx> {
     temporary_used_locals: FxIndexSet<Local>,
     never_initialized_mut_locals: &'visit mut FxIndexSet<Local>,
-    mbcx: &'visit mut MirBorrowckCtxt<'a, 'mir, 'cx, 'tcx>,
+    mbcx: &'visit mut MirBorrowckCtxt<'a, 'mir, 'infcx, 'tcx>,
 }
 
 impl GatherUsedMutsVisitor<'_, '_, '_, '_, '_> {

compiler/rustc_errors/src/diagnostic.rs

@@ -510,7 +510,7 @@ pub struct Diag<'a, G: EmissionGuarantee = ErrorGuaranteed> {
 // would be bad.
 impl<G> !Clone for Diag<'_, G> {}
 
-rustc_data_structures::static_assert_size!(Diag<'_, ()>, 2 * std::mem::size_of::<usize>());
+rustc_data_structures::static_assert_size!(Diag<'_, ()>, 3 * std::mem::size_of::<usize>());
 
 impl<G: EmissionGuarantee> Deref for Diag<'_, G> {
     type Target = DiagInner;
@@ -582,6 +582,11 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
         Self::new_diagnostic(dcx, DiagInner::new(level, message))
     }
 
+    /// Allow moving diagnostics between different error tainting contexts
+    pub fn with_dcx(mut self, dcx: DiagCtxtHandle<'_>) -> Diag<'_, G> {
+        Diag { dcx, diag: self.diag.take(), _marker: PhantomData }
+    }
+
     /// Creates a new `Diag` with an already constructed diagnostic.
     #[track_caller]
     pub(crate) fn new_diagnostic(dcx: DiagCtxtHandle<'a>, diag: DiagInner) -> Self {

compiler/rustc_errors/src/lib.rs

@@ -63,6 +63,7 @@ use rustc_span::source_map::SourceMap;
 use rustc_span::{Loc, Span, DUMMY_SP};
 use std::backtrace::{Backtrace, BacktraceStatus};
 use std::borrow::Cow;
+use std::cell::Cell;
 use std::error::Report;
 use std::fmt;
 use std::hash::Hash;
@@ -98,9 +99,9 @@ rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
 // `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_pointer_width = "64")]
-rustc_data_structures::static_assert_size!(PResult<'_, ()>, 16);
+rustc_data_structures::static_assert_size!(PResult<'_, ()>, 24);
 #[cfg(target_pointer_width = "64")]
-rustc_data_structures::static_assert_size!(PResult<'_, bool>, 16);
+rustc_data_structures::static_assert_size!(PResult<'_, bool>, 24);
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, Encodable, Decodable)]
 pub enum SuggestionStyle {
@@ -417,6 +418,9 @@ pub struct DiagCtxt {
 #[derive(Copy, Clone)]
 pub struct DiagCtxtHandle<'a> {
     dcx: &'a DiagCtxt,
+    /// Some contexts create `DiagCtxtHandle` with this field set, and thus all
+    /// errors emitted with it will automatically taint when emitting errors.
+    tainted_with_errors: Option<&'a Cell<Option<ErrorGuaranteed>>>,
 }
 
 impl<'a> std::ops::Deref for DiagCtxtHandle<'a> {
@@ -752,7 +756,17 @@ impl DiagCtxt {
     }
 
     pub fn handle<'a>(&'a self) -> DiagCtxtHandle<'a> {
-        DiagCtxtHandle { dcx: self }
+        DiagCtxtHandle { dcx: self, tainted_with_errors: None }
+    }
+
+    /// Link this to a taintable context so that emitting errors will automatically set
+    /// the `Option<ErrorGuaranteed>` instead of having to do that manually at every error
+    /// emission site.
+    pub fn taintable_handle<'a>(
+        &'a self,
+        tainted_with_errors: &'a Cell<Option<ErrorGuaranteed>>,
+    ) -> DiagCtxtHandle<'a> {
+        DiagCtxtHandle { dcx: self, tainted_with_errors: Some(tainted_with_errors) }
     }
 }
 
@@ -795,7 +809,9 @@ impl<'a> DiagCtxtHandle<'a> {
             // can be used to create a backtrace at the stashing site insted of whenever the
             // diagnostic context is dropped and thus delayed bugs are emitted.
             Error => Some(self.span_delayed_bug(span, format!("stashing {key:?}"))),
-            DelayedBug => return self.inner.borrow_mut().emit_diagnostic(diag),
+            DelayedBug => {
+                return self.inner.borrow_mut().emit_diagnostic(diag, self.tainted_with_errors);
+            }
             ForceWarning(_) | Warning | Note | OnceNote | Help | OnceHelp | FailureNote | Allow
             | Expect(_) => None,
         };
@@ -947,16 +963,19 @@ impl<'a> DiagCtxtHandle<'a> {
             (0, _) => {
                 // Use `ForceWarning` rather than `Warning` to guarantee emission, e.g. with a
                 // configuration like `--cap-lints allow --force-warn bare_trait_objects`.
-                inner.emit_diagnostic(DiagInner::new(
+                inner.emit_diagnostic(
-                    ForceWarning(None),
+                    DiagInner::new(ForceWarning(None), DiagMessage::Str(warnings)),
-                    DiagMessage::Str(warnings),
+                    None,
-                ));
+                );
             }
             (_, 0) => {
-                inner.emit_diagnostic(DiagInner::new(Error, errors));
+                inner.emit_diagnostic(DiagInner::new(Error, errors), self.tainted_with_errors);
             }
             (_, _) => {
-                inner.emit_diagnostic(DiagInner::new(Error, format!("{errors}; {warnings}")));
+                inner.emit_diagnostic(
+                    DiagInner::new(Error, format!("{errors}; {warnings}")),
+                    self.tainted_with_errors,
+                );
             }
         }
 
@@ -987,14 +1006,14 @@ impl<'a> DiagCtxtHandle<'a> {
                         "For more information about an error, try `rustc --explain {}`.",
                         &error_codes[0]
                     );
-                    inner.emit_diagnostic(DiagInner::new(FailureNote, msg1));
+                    inner.emit_diagnostic(DiagInner::new(FailureNote, msg1), None);
-                    inner.emit_diagnostic(DiagInner::new(FailureNote, msg2));
+                    inner.emit_diagnostic(DiagInner::new(FailureNote, msg2), None);
                 } else {
                     let msg = format!(
                         "For more information about this error, try `rustc --explain {}`.",
                         &error_codes[0]
                     );
-                    inner.emit_diagnostic(DiagInner::new(FailureNote, msg));
+                    inner.emit_diagnostic(DiagInner::new(FailureNote, msg), None);
                 }
             }
         }
@@ -1020,7 +1039,7 @@ impl<'a> DiagCtxtHandle<'a> {
     }
 
     pub fn emit_diagnostic(&self, diagnostic: DiagInner) -> Option<ErrorGuaranteed> {
-        self.inner.borrow_mut().emit_diagnostic(diagnostic)
+        self.inner.borrow_mut().emit_diagnostic(diagnostic, self.tainted_with_errors)
     }
 
     pub fn emit_artifact_notification(&self, path: &Path, artifact_type: &str) {
@@ -1080,7 +1099,7 @@ impl<'a> DiagCtxtHandle<'a> {
                 // Here the diagnostic is given back to `emit_diagnostic` where it was first
                 // intercepted. Now it should be processed as usual, since the unstable expectation
                 // id is now stable.
-                inner.emit_diagnostic(diag);
+                inner.emit_diagnostic(diag, self.tainted_with_errors);
             }
         }
 
@@ -1430,13 +1449,17 @@ impl DiagCtxtInner {
                     continue;
                 }
             }
-            guar = guar.or(self.emit_diagnostic(diag));
+            guar = guar.or(self.emit_diagnostic(diag, None));
         }
         guar
     }
 
     // Return value is only `Some` if the level is `Error` or `DelayedBug`.
-    fn emit_diagnostic(&mut self, mut diagnostic: DiagInner) -> Option<ErrorGuaranteed> {
+    fn emit_diagnostic(
+        &mut self,
+        mut diagnostic: DiagInner,
+        taint: Option<&Cell<Option<ErrorGuaranteed>>>,
+    ) -> Option<ErrorGuaranteed> {
         match diagnostic.level {
             Expect(expect_id) | ForceWarning(Some(expect_id)) => {
                 // The `LintExpectationId` can be stable or unstable depending on when it was
@@ -1609,6 +1632,9 @@ impl DiagCtxtInner {
                 if is_lint {
                     self.lint_err_guars.push(guar);
                 } else {
+                    if let Some(taint) = taint {
+                        taint.set(Some(guar));
+                    }
                     self.err_guars.push(guar);
                 }
                 self.panic_if_treat_err_as_bug();
@@ -1718,8 +1744,8 @@ impl DiagCtxtInner {
         // `-Ztreat-err-as-bug`, which we don't want.
         let note1 = "no errors encountered even though delayed bugs were created";
         let note2 = "those delayed bugs will now be shown as internal compiler errors";
-        self.emit_diagnostic(DiagInner::new(Note, note1));
+        self.emit_diagnostic(DiagInner::new(Note, note1), None);
-        self.emit_diagnostic(DiagInner::new(Note, note2));
+        self.emit_diagnostic(DiagInner::new(Note, note2), None);
 
         for bug in bugs {
             if let Some(out) = &mut out {
@@ -1752,7 +1778,7 @@ impl DiagCtxtInner {
             }
             bug.level = Bug;
 
-            self.emit_diagnostic(bug);
+            self.emit_diagnostic(bug, None);
         }
 
         // Panic with `DelayedBugPanic` to avoid "unexpected panic" messages.

compiler/rustc_hir_typeck/src/cast.rs

@@ -319,7 +319,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 } else {
                     errors::CannotCastToBoolHelp::Unsupported(self.span)
                 };
-                fcx.tcx.dcx().emit_err(errors::CannotCastToBool { span: self.span, expr_ty, help });
+                fcx.dcx().emit_err(errors::CannotCastToBool { span: self.span, expr_ty, help });
             }
             CastError::CastToChar => {
                 let mut err = type_error_struct!(

compiler/rustc_hir_typeck/src/coercion.rs

@@ -1797,16 +1797,16 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         err.subdiagnostic(SuggestBoxingForReturnImplTrait::BoxReturnExpr { starts, ends });
     }
 
-    fn report_return_mismatched_types<'a>(
+    fn report_return_mismatched_types<'infcx>(
         &self,
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         found: Ty<'tcx>,
         ty_err: TypeError<'tcx>,
-        fcx: &FnCtxt<'a, 'tcx>,
+        fcx: &'infcx FnCtxt<'_, 'tcx>,
         block_or_return_id: hir::HirId,
         expression: Option<&'tcx hir::Expr<'tcx>>,
-    ) -> Diag<'a> {
+    ) -> Diag<'infcx> {
         let mut err = fcx.err_ctxt().report_mismatched_types(cause, expected, found, ty_err);
 
         let due_to_block = matches!(fcx.tcx.hir_node(block_or_return_id), hir::Node::Block(..));

compiler/rustc_hir_typeck/src/demand.rs

@@ -172,21 +172,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     pub fn demand_suptype_diag(
-        &self,
+        &'a self,
         sp: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Result<(), Diag<'tcx>> {
+    ) -> Result<(), Diag<'a>> {
         self.demand_suptype_with_origin(&self.misc(sp), expected, actual)
     }
 
     #[instrument(skip(self), level = "debug")]
     pub fn demand_suptype_with_origin(
-        &self,
+        &'a self,
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Result<(), Diag<'tcx>> {
+    ) -> Result<(), Diag<'a>> {
         self.at(cause, self.param_env)
             .sup(DefineOpaqueTypes::Yes, expected, actual)
             .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
@@ -200,20 +200,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     pub fn demand_eqtype_diag(
-        &self,
+        &'a self,
         sp: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Result<(), Diag<'tcx>> {
+    ) -> Result<(), Diag<'a>> {
         self.demand_eqtype_with_origin(&self.misc(sp), expected, actual)
     }
 
     pub fn demand_eqtype_with_origin(
-        &self,
+        &'a self,
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Result<(), Diag<'tcx>> {
+    ) -> Result<(), Diag<'a>> {
         self.at(cause, self.param_env)
             .eq(DefineOpaqueTypes::Yes, expected, actual)
             .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
@@ -247,13 +247,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// will be permitted if the diverges flag is currently "always".
     #[instrument(level = "debug", skip(self, expr, expected_ty_expr, allow_two_phase))]
     pub fn demand_coerce_diag(
-        &self,
+        &'a self,
         mut expr: &'tcx hir::Expr<'tcx>,
         checked_ty: Ty<'tcx>,
         expected: Ty<'tcx>,
         mut expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
         allow_two_phase: AllowTwoPhase,
-    ) -> Result<Ty<'tcx>, Diag<'tcx>> {
+    ) -> Result<Ty<'tcx>, Diag<'a>> {
         let expected = self.resolve_vars_with_obligations(expected);
 
         let e = match self.coerce(expr, checked_ty, expected, allow_two_phase, None) {

compiler/rustc_hir_typeck/src/expr.rs

@@ -638,7 +638,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // Set expectation to error in that case and set tainted
                 // by error (#114529)
                 let coerce_to = opt_coerce_to.unwrap_or_else(|| {
-                    let guar = tcx.dcx().span_delayed_bug(
+                    let guar = self.dcx().span_delayed_bug(
                         expr.span,
                         "illegal break with value found but no error reported",
                     );
@@ -1716,7 +1716,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             } else {
                 error_happened = true;
                 let guar = if let Some(prev_span) = seen_fields.get(&ident) {
-                    tcx.dcx().emit_err(FieldMultiplySpecifiedInInitializer {
+                    self.dcx().emit_err(FieldMultiplySpecifiedInInitializer {
                         span: field.ident.span,
                         prev_span: *prev_span,
                         ident,
@@ -1757,7 +1757,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if adt_kind == AdtKind::Union {
             if hir_fields.len() != 1 {
                 struct_span_code_err!(
-                    tcx.dcx(),
+                    self.dcx(),
                     span,
                     E0784,
                     "union expressions should have exactly one field",

compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -170,7 +170,7 @@ impl<'tcx> TypeInformationCtxt<'tcx> for &FnCtxt<'_, 'tcx> {
     }
 
     fn report_error(&self, span: Span, msg: impl ToString) -> Self::Error {
-        self.tcx.dcx().span_delayed_bug(span, msg.to_string())
+        self.dcx().span_delayed_bug(span, msg.to_string())
     }
 
     fn error_reported_in_ty(&self, ty: Ty<'tcx>) -> Result<(), Self::Error> {

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -1182,7 +1182,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     name: self.tcx.item_name(def.did()).to_ident_string(),
                 });
                 if ty.raw.has_param() {
-                    let guar = self.tcx.dcx().emit_err(errors::SelfCtorFromOuterItem {
+                    let guar = self.dcx().emit_err(errors::SelfCtorFromOuterItem {
                         span: path_span,
                         impl_span: tcx.def_span(impl_def_id),
                         sugg,
@@ -1207,7 +1207,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // Check the visibility of the ctor.
                     let vis = tcx.visibility(ctor_def_id);
                     if !vis.is_accessible_from(tcx.parent_module(hir_id).to_def_id(), tcx) {
-                        tcx.dcx()
+                        self.dcx()
                             .emit_err(CtorIsPrivate { span, def: tcx.def_path_str(adt_def.did()) });
                     }
                     let new_res = Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
@@ -1216,7 +1216,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     (new_res, Some(user_args.args))
                 }
                 _ => {
-                    let mut err = tcx.dcx().struct_span_err(
+                    let mut err = self.dcx().struct_span_err(
                         span,
                         "the `Self` constructor can only be used with tuple or unit structs",
                     );

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -238,7 +238,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // Otherwise, there's a mismatch, so clear out what we're expecting, and set
                     // our input types to err_args so we don't blow up the error messages
                     let guar = struct_span_code_err!(
-                        tcx.dcx(),
+                        self.dcx(),
                         call_span,
                         E0059,
                         "cannot use call notation; the first type parameter \
@@ -453,7 +453,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .map(|vars| self.resolve_vars_if_possible(vars)),
             );
 
-            self.set_tainted_by_errors(self.report_arg_errors(
+            self.report_arg_errors(
                 compatibility_diagonal,
                 formal_and_expected_inputs,
                 provided_args,
@@ -462,7 +462,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 fn_def_id,
                 call_span,
                 call_expr,
-            ));
+            );
         }
     }
 
@@ -788,7 +788,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             format!("arguments to this {call_name} are incorrect"),
                         );
                     } else {
-                        err = tcx.dcx().struct_span_err(
+                        err = self.dcx().struct_span_err(
                             full_call_span,
                             format!(
                                 "{call_name} takes {}{} but {} {} supplied",
@@ -848,7 +848,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 span_bug!(error_span, "expected errors from argument matrix");
             } else {
                 let mut err =
-                    tcx.dcx().create_err(errors::ArgMismatchIndeterminate { span: error_span });
+                    self.dcx().create_err(errors::ArgMismatchIndeterminate { span: error_span });
                 suggest_confusable(&mut err);
                 return err.emit();
             }
@@ -953,14 +953,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let mut err = if formal_and_expected_inputs.len() == provided_args.len() {
             struct_span_code_err!(
-                tcx.dcx(),
+                self.dcx(),
                 full_call_span,
                 E0308,
                 "arguments to this {} are incorrect",
                 call_name,
             )
         } else {
-            tcx.dcx()
+            self.dcx()
                 .struct_span_err(
                     full_call_span,
                     format!(
@@ -1424,7 +1424,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected_ty: Ty<'tcx>,
         provided_ty: Ty<'tcx>,
         arg: &hir::Expr<'tcx>,
-        err: &mut Diag<'tcx>,
+        err: &mut Diag<'_>,
     ) {
         if let ty::RawPtr(_, hir::Mutability::Mut) = expected_ty.kind()
             && let ty::RawPtr(_, hir::Mutability::Not) = provided_ty.kind()

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -144,8 +144,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(crate) fn dcx(&self) -> DiagCtxtHandle<'tcx> {
+    pub(crate) fn dcx(&self) -> DiagCtxtHandle<'a> {
-        self.infcx.dcx()
+        self.root_ctxt.infcx.dcx()
     }
 
     pub fn cause(&self, span: Span, code: ObligationCauseCode<'tcx>) -> ObligationCause<'tcx> {

compiler/rustc_hir_typeck/src/intrinsicck.rs

@@ -52,7 +52,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Note: this path is currently not reached in any test, so any
             // example that triggers this would be worth minimizing and
             // converting into a test.
-            tcx.dcx().span_bug(span, "argument to transmute has inference variables");
+            self.dcx().span_bug(span, "argument to transmute has inference variables");
         }
         // Transmutes that are only changing lifetimes are always ok.
         if from == to {
@@ -76,7 +76,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if let (&ty::FnDef(..), SizeSkeleton::Known(size_to, _)) = (from.kind(), sk_to)
                 && size_to == Pointer(dl.instruction_address_space).size(&tcx)
             {
-                struct_span_code_err!(tcx.dcx(), span, E0591, "can't transmute zero-sized type")
+                struct_span_code_err!(self.dcx(), span, E0591, "can't transmute zero-sized type")
                     .with_note(format!("source type: {from}"))
                     .with_note(format!("target type: {to}"))
                     .with_help("cast with `as` to a pointer instead")
@@ -116,7 +116,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         let mut err = struct_span_code_err!(
-            tcx.dcx(),
+            self.dcx(),
             span,
             E0512,
             "cannot transmute between types of different sizes, \

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -705,7 +705,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mut err = if is_write && let SelfSource::MethodCall(rcvr_expr) = source {
             self.suggest_missing_writer(rcvr_ty, rcvr_expr)
         } else {
-            let mut err = tcx.dcx().create_err(NoAssociatedItem {
+            let mut err = self.dcx().create_err(NoAssociatedItem {
                 span,
                 item_kind,
                 item_name,
@@ -1194,7 +1194,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         span: item_span,
                         ..
                     })) => {
-                        tcx.dcx().span_delayed_bug(
+                        self.dcx().span_delayed_bug(
                             *item_span,
                             "auto trait is invoked with no method error, but no error reported?",
                         );
@@ -2361,7 +2361,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     );
                     if pick.is_ok() {
                         let range_span = parent_expr.span.with_hi(expr.span.hi());
-                        return Err(tcx.dcx().emit_err(errors::MissingParenthesesInRange {
+                        return Err(self.dcx().emit_err(errors::MissingParenthesesInRange {
                             span,
                             ty_str: ty_str.to_string(),
                             method_name: item_name.as_str().to_string(),
@@ -2420,7 +2420,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             && let SelfSource::MethodCall(expr) = source
         {
             let mut err = struct_span_code_err!(
-                tcx.dcx(),
+                self.dcx(),
                 span,
                 E0689,
                 "can't call {} `{}` on ambiguous numeric type `{}`",

compiler/rustc_hir_typeck/src/pat.rs

@@ -89,7 +89,7 @@ struct PatInfo<'tcx, 'a> {
     current_depth: u32,
 }
 
-impl<'tcx> FnCtxt<'_, 'tcx> {
+impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn pattern_cause(&self, ti: &TopInfo<'tcx>, cause_span: Span) -> ObligationCause<'tcx> {
         let code = ObligationCauseCode::Pattern {
             span: ti.span,
@@ -100,12 +100,12 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
     }
 
     fn demand_eqtype_pat_diag(
-        &self,
+        &'a self,
         cause_span: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
         ti: &TopInfo<'tcx>,
-    ) -> Result<(), Diag<'tcx>> {
+    ) -> Result<(), Diag<'a>> {
         self.demand_eqtype_with_origin(&self.pattern_cause(ti, cause_span), expected, actual)
             .map_err(|mut diag| {
                 if let Some(expr) = ti.origin_expr {
@@ -698,7 +698,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             && let MutblCap::WeaklyNot(and_pat_span) = pat_info.max_ref_mutbl
         {
             let mut err = struct_span_code_err!(
-                self.tcx.dcx(),
+                self.dcx(),
                 ident.span,
                 E0596,
                 "cannot borrow as mutable inside an `&` pattern"
@@ -1010,7 +1010,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let (res, opt_ty, segments) = path_resolution;
         match res {
             Res::Err => {
-                let e = tcx.dcx().span_delayed_bug(qpath.span(), "`Res::Err` but no error emitted");
+                let e =
+                    self.dcx().span_delayed_bug(qpath.span(), "`Res::Err` but no error emitted");
                 self.set_tainted_by_errors(e);
                 return Ty::new_error(tcx, e);
             }
@@ -1191,7 +1192,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let (res, opt_ty, segments) =
             self.resolve_ty_and_res_fully_qualified_call(qpath, pat.hir_id, pat.span);
         if res == Res::Err {
-            let e = tcx.dcx().span_delayed_bug(pat.span, "`Res::Err` but no error emitted");
+            let e = self.dcx().span_delayed_bug(pat.span, "`Res::Err` but no error emitted");
             self.set_tainted_by_errors(e);
             on_error(e);
             return Ty::new_error(tcx, e);
@@ -1207,7 +1208,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let variant = match res {
             Res::Err => {
-                tcx.dcx().span_bug(pat.span, "`Res::Err` but no error emitted");
+                self.dcx().span_bug(pat.span, "`Res::Err` but no error emitted");
             }
             Res::Def(DefKind::AssocConst | DefKind::AssocFn, _) => {
                 let e = report_unexpected_res(res);
@@ -1549,10 +1550,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Report an error if an incorrect number of fields was specified.
         if adt.is_union() {
             if fields.len() != 1 {
-                tcx.dcx().emit_err(errors::UnionPatMultipleFields { span: pat.span });
+                self.dcx().emit_err(errors::UnionPatMultipleFields { span: pat.span });
             }
             if has_rest_pat {
-                tcx.dcx().emit_err(errors::UnionPatDotDot { span: pat.span });
+                self.dcx().emit_err(errors::UnionPatDotDot { span: pat.span });
             }
         } else if !unmentioned_fields.is_empty() {
             let accessible_unmentioned_fields: Vec<_> = unmentioned_fields
@@ -1690,7 +1691,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         pat: &'tcx Pat<'tcx>,
         variant: &ty::VariantDef,
         args: ty::GenericArgsRef<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let tcx = self.tcx;
         let (field_names, t, plural) = if let [field] = inexistent_fields {
             (format!("a field named `{}`", field.ident), "this", "")
@@ -1710,7 +1711,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
         let spans = inexistent_fields.iter().map(|field| field.ident.span).collect::<Vec<_>>();
         let mut err = struct_span_code_err!(
-            tcx.dcx(),
+            self.dcx(),
             spans,
             E0026,
             "{} `{}` does not have {}",
@@ -1881,7 +1882,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         pat: &Pat<'_>,
         fields: &'tcx [hir::PatField<'tcx>],
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let mut err = self
             .dcx()
             .struct_span_err(pat.span, "pattern requires `..` due to inaccessible fields");
@@ -1973,7 +1974,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         unmentioned_fields: &[(&ty::FieldDef, Ident)],
         have_inaccessible_fields: bool,
         fields: &'tcx [hir::PatField<'tcx>],
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let inaccessible = if have_inaccessible_fields { " and inaccessible fields" } else { "" };
         let field_names = if let [(_, field)] = unmentioned_fields {
             format!("field `{field}`{inaccessible}")

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -139,7 +139,7 @@ pub struct TypeErrCtxt<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
-    pub fn dcx(&self) -> DiagCtxtHandle<'tcx> {
+    pub fn dcx(&self) -> DiagCtxtHandle<'a> {
         self.infcx.dcx()
     }
 
@@ -305,16 +305,17 @@ fn label_msg_span(
     }
 }
 
-#[instrument(level = "trace", skip(tcx))]
+#[instrument(level = "trace", skip(infcx))]
-pub fn unexpected_hidden_region_diagnostic<'tcx>(
+pub fn unexpected_hidden_region_diagnostic<'a, 'tcx>(
-    tcx: TyCtxt<'tcx>,
+    infcx: &'a InferCtxt<'tcx>,
     generic_param_scope: LocalDefId,
     span: Span,
     hidden_ty: Ty<'tcx>,
     hidden_region: ty::Region<'tcx>,
     opaque_ty_key: ty::OpaqueTypeKey<'tcx>,
-) -> Diag<'tcx> {
+) -> Diag<'a> {
-    let mut err = tcx.dcx().create_err(errors::OpaqueCapturesLifetime {
+    let tcx = infcx.tcx;
+    let mut err = infcx.dcx().create_err(errors::OpaqueCapturesLifetime {
         span,
         opaque_ty: Ty::new_opaque(tcx, opaque_ty_key.def_id.to_def_id(), opaque_ty_key.args),
         opaque_ty_span: tcx.def_span(opaque_ty_key.def_id),
@@ -436,7 +437,7 @@ impl<'tcx> InferCtxt<'tcx> {
     }
 }
 
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     pub fn report_region_errors(
         &self,
         generic_param_scope: LocalDefId,
@@ -2206,7 +2207,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         &self,
         trace: TypeTrace<'tcx>,
         terr: TypeError<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         debug!("report_and_explain_type_error(trace={:?}, terr={:?})", trace, terr);
 
         let span = trace.cause.span();
@@ -2215,7 +2216,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             span,
             self.type_error_additional_suggestions(&trace, terr),
         );
-        let mut diag = self.tcx.dcx().create_err(failure_code);
+        let mut diag = self.dcx().create_err(failure_code);
         self.note_type_err(&mut diag, &trace.cause, None, Some(trace.values), terr, false, false);
         diag
     }
@@ -2357,14 +2358,14 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         origin: Option<SubregionOrigin<'tcx>>,
         bound_kind: GenericKind<'tcx>,
         sub: Region<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         if let Some(SubregionOrigin::CompareImplItemObligation {
             span,
             impl_item_def_id,
             trait_item_def_id,
         }) = origin
         {
-            return self.report_extra_impl_obligation(
+            return self.infcx.report_extra_impl_obligation(
                 span,
                 impl_item_def_id,
                 trait_item_def_id,
@@ -2790,7 +2791,7 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for SameTypeModuloInfer<'_, 'tcx> {
 }
 
 impl<'tcx> InferCtxt<'tcx> {
-    fn report_inference_failure(&self, var_origin: RegionVariableOrigin) -> Diag<'tcx> {
+    fn report_inference_failure(&self, var_origin: RegionVariableOrigin) -> Diag<'_> {
         let br_string = |br: ty::BoundRegionKind| {
             let mut s = match br {
                 ty::BrNamed(_, name) => name.to_string(),
@@ -2829,7 +2830,7 @@ impl<'tcx> InferCtxt<'tcx> {
         };
 
         struct_span_code_err!(
-            self.tcx.dcx(),
+            self.dcx(),
             var_origin.span(),
             E0495,
             "cannot infer an appropriate lifetime{} due to conflicting requirements",

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -391,7 +391,7 @@ impl<'tcx> InferCtxt<'tcx> {
         span: Span,
         arg_data: InferenceDiagnosticsData,
         error_code: TypeAnnotationNeeded,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'_> {
         let source_kind = "other";
         let source_name = "";
         let failure_span = None;
@@ -436,7 +436,7 @@ impl<'tcx> InferCtxt<'tcx> {
     }
 }
 
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     #[instrument(level = "debug", skip(self, error_code))]
     pub fn emit_inference_failure_err(
         &self,
@@ -445,7 +445,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         arg: GenericArg<'tcx>,
         error_code: TypeAnnotationNeeded,
         should_label_span: bool,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let arg = self.resolve_vars_if_possible(arg);
         let arg_data = self.extract_inference_diagnostics_data(arg, None);
 
@@ -453,7 +453,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             // If we don't have any typeck results we're outside
             // of a body, so we won't be able to get better info
             // here.
-            return self.bad_inference_failure_err(failure_span, arg_data, error_code);
+            return self.infcx.bad_inference_failure_err(failure_span, arg_data, error_code);
         };
 
         let mut local_visitor = FindInferSourceVisitor::new(self, typeck_results, arg);
@@ -465,7 +465,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         }
 
         let Some(InferSource { span, kind }) = local_visitor.infer_source else {
-            return self.bad_inference_failure_err(failure_span, arg_data, error_code);
+            return self.infcx.bad_inference_failure_err(failure_span, arg_data, error_code);
         };
 
         let (source_kind, name, path) = kind.ty_localized_msg(self);

compiler/rustc_infer/src/infer/error_reporting/note.rs

@@ -14,7 +14,7 @@ use rustc_span::symbol::kw;
 
 use super::ObligationCauseAsDiagArg;
 
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     pub(super) fn note_region_origin(&self, err: &mut Diag<'_>, origin: &SubregionOrigin<'tcx>) {
         match *origin {
             infer::Subtype(ref trace) => RegionOriginNote::WithRequirement {
@@ -79,7 +79,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         origin: SubregionOrigin<'tcx>,
         sub: Region<'tcx>,
         sup: Region<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let mut err = match origin {
             infer::Subtype(box trace) => {
                 let terr = TypeError::RegionsDoesNotOutlive(sup, sub);
@@ -245,7 +245,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 })
             }
             infer::CompareImplItemObligation { span, impl_item_def_id, trait_item_def_id } => {
-                let mut err = self.report_extra_impl_obligation(
+                let mut err = self.infcx.report_extra_impl_obligation(
                     span,
                     impl_item_def_id,
                     trait_item_def_id,
@@ -378,7 +378,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         placeholder_origin: SubregionOrigin<'tcx>,
         sub: Region<'tcx>,
         sup: Region<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         // I can't think how to do better than this right now. -nikomatsakis
         debug!(?placeholder_origin, ?sub, ?sup, "report_placeholder_failure");
         match placeholder_origin {

compiler/rustc_infer/src/infer/mod.rs

@@ -684,8 +684,8 @@ impl<'tcx> InferOk<'tcx, ()> {
 }
 
 impl<'tcx> InferCtxt<'tcx> {
-    pub fn dcx(&self) -> DiagCtxtHandle<'tcx> {
+    pub fn dcx(&self) -> DiagCtxtHandle<'_> {
-        self.tcx.dcx()
+        self.tcx.dcx().taintable_handle(&self.tainted_by_errors)
     }
 
     pub fn defining_opaque_types(&self) -> &'tcx ty::List<LocalDefId> {
@@ -1089,19 +1089,7 @@ impl<'tcx> InferCtxt<'tcx> {
     /// inference variables, regionck errors).
     #[must_use = "this method does not have any side effects"]
     pub fn tainted_by_errors(&self) -> Option<ErrorGuaranteed> {
-        if let Some(guar) = self.tainted_by_errors.get() {
+        self.tainted_by_errors.get()
-            Some(guar)
-        } else if self.dcx().err_count_excluding_lint_errs() > self.err_count_on_creation {
-            // Errors reported since this infcx was made. Lint errors are
-            // excluded to avoid some being swallowed in the presence of
-            // non-lint errors. (It's arguable whether or not this exclusion is
-            // important.)
-            let guar = self.dcx().has_errors().unwrap();
-            self.set_tainted_by_errors(guar);
-            Some(guar)
-        } else {
-            None
-        }
     }
 
     /// Set the "tainted by errors" flag to true. We call this when we
@@ -1328,8 +1316,7 @@ impl<'tcx> InferCtxt<'tcx> {
                     bug!("`{value:?}` is not fully resolved");
                 }
                 if value.has_infer_regions() {
-                    let guar =
+                    let guar = self.dcx().delayed_bug(format!("`{value:?}` is not fully resolved"));
-                        self.tcx.dcx().delayed_bug(format!("`{value:?}` is not fully resolved"));
                     Ok(self.tcx.fold_regions(value, |re, _| {
                         if re.is_var() { ty::Region::new_error(self.tcx, guar) } else { re }
                     }))
@@ -1607,7 +1594,7 @@ impl<'tcx> InferCtxt<'tcx> {
     }
 }
 
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     // [Note-Type-error-reporting]
     // An invariant is that anytime the expected or actual type is Error (the special
     // error type, meaning that an error occurred when typechecking this expression),
@@ -1623,9 +1610,9 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         sp: Span,
         mk_diag: M,
         actual_ty: Ty<'tcx>,
-    ) -> Diag<'tcx>
+    ) -> Diag<'a>
     where
-        M: FnOnce(String) -> Diag<'tcx>,
+        M: FnOnce(String) -> Diag<'a>,
     {
         let actual_ty = self.resolve_vars_if_possible(actual_ty);
         debug!("type_error_struct_with_diag({:?}, {:?})", sp, actual_ty);
@@ -1646,7 +1633,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
         err: TypeError<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         self.report_and_explain_type_error(TypeTrace::types(cause, true, expected, actual), err)
     }
 
@@ -1656,7 +1643,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         expected: ty::Const<'tcx>,
         actual: ty::Const<'tcx>,
         err: TypeError<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         self.report_and_explain_type_error(TypeTrace::consts(cause, true, expected, actual), err)
     }
 }

compiler/rustc_infer/src/infer/opaque_types/mod.rs

@@ -156,7 +156,7 @@ impl<'tcx> InferCtxt<'tcx> {
                     if self.can_define_opaque_ty(b_def_id)
                         && self.tcx.is_type_alias_impl_trait(b_def_id)
                     {
-                        self.tcx.dcx().emit_err(OpaqueHiddenTypeDiag {
+                        self.dcx().emit_err(OpaqueHiddenTypeDiag {
                             span,
                             hidden_type: self.tcx.def_span(b_def_id),
                             opaque_type: self.tcx.def_span(def_id),

compiler/rustc_infer/src/traits/error_reporting/mod.rs

@@ -12,15 +12,15 @@ use std::fmt;
 use std::iter;
 
 impl<'tcx> InferCtxt<'tcx> {
-    pub fn report_extra_impl_obligation(
+    pub fn report_extra_impl_obligation<'a>(
-        &self,
+        &'a self,
         error_span: Span,
         impl_item_def_id: LocalDefId,
         trait_item_def_id: DefId,
         requirement: &dyn fmt::Display,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let mut err = struct_span_code_err!(
-            self.tcx.dcx(),
+            self.dcx(),
             error_span,
             E0276,
             "impl has stricter requirements than trait"

compiler/rustc_mir_dataflow/src/impls/initialized.rs

@@ -50,15 +50,19 @@ use crate::{lattice, AnalysisDomain, GenKill, GenKillAnalysis, MaybeReachable};
 /// Similarly, at a given `drop` statement, the set-intersection
 /// between this data and `MaybeUninitializedPlaces` yields the set of
 /// places that would require a dynamic drop-flag at that statement.
-pub struct MaybeInitializedPlaces<'a, 'tcx> {
+pub struct MaybeInitializedPlaces<'a, 'mir, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    body: &'a Body<'tcx>,
+    body: &'mir Body<'tcx>,
     mdpe: &'a MoveDataParamEnv<'tcx>,
     skip_unreachable_unwind: bool,
 }
 
-impl<'a, 'tcx> MaybeInitializedPlaces<'a, 'tcx> {
+impl<'a, 'mir, 'tcx> MaybeInitializedPlaces<'a, 'mir, 'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, mdpe: &'a MoveDataParamEnv<'tcx>) -> Self {
+    pub fn new(
+        tcx: TyCtxt<'tcx>,
+        body: &'mir Body<'tcx>,
+        mdpe: &'a MoveDataParamEnv<'tcx>,
+    ) -> Self {
         MaybeInitializedPlaces { tcx, body, mdpe, skip_unreachable_unwind: false }
     }
 
@@ -84,7 +88,7 @@ impl<'a, 'tcx> MaybeInitializedPlaces<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> HasMoveData<'tcx> for MaybeInitializedPlaces<'a, 'tcx> {
+impl<'a, 'mir, 'tcx> HasMoveData<'tcx> for MaybeInitializedPlaces<'a, 'mir, 'tcx> {
     fn move_data(&self) -> &MoveData<'tcx> {
         &self.mdpe.move_data
     }
@@ -125,17 +129,21 @@ impl<'a, 'tcx> HasMoveData<'tcx> for MaybeInitializedPlaces<'a, 'tcx> {
 /// Similarly, at a given `drop` statement, the set-intersection
 /// between this data and `MaybeInitializedPlaces` yields the set of
 /// places that would require a dynamic drop-flag at that statement.
-pub struct MaybeUninitializedPlaces<'a, 'tcx> {
+pub struct MaybeUninitializedPlaces<'a, 'mir, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    body: &'a Body<'tcx>,
+    body: &'mir Body<'tcx>,
     mdpe: &'a MoveDataParamEnv<'tcx>,
 
     mark_inactive_variants_as_uninit: bool,
     skip_unreachable_unwind: BitSet<mir::BasicBlock>,
 }
 
-impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx> {
+impl<'a, 'mir, 'tcx> MaybeUninitializedPlaces<'a, 'mir, 'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, mdpe: &'a MoveDataParamEnv<'tcx>) -> Self {
+    pub fn new(
+        tcx: TyCtxt<'tcx>,
+        body: &'mir Body<'tcx>,
+        mdpe: &'a MoveDataParamEnv<'tcx>,
+    ) -> Self {
         MaybeUninitializedPlaces {
             tcx,
             body,
@@ -164,7 +172,7 @@ impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'a, 'tcx> {
+impl<'a, 'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'a, '_, 'tcx> {
     fn move_data(&self) -> &MoveData<'tcx> {
         &self.mdpe.move_data
     }
@@ -250,24 +258,24 @@ impl<'a, 'tcx> HasMoveData<'tcx> for DefinitelyInitializedPlaces<'a, 'tcx> {
 ///     c = S;                                  // {a, b, c, d }
 /// }
 /// ```
-pub struct EverInitializedPlaces<'a, 'tcx> {
+pub struct EverInitializedPlaces<'a, 'mir, 'tcx> {
-    body: &'a Body<'tcx>,
+    body: &'mir Body<'tcx>,
     mdpe: &'a MoveDataParamEnv<'tcx>,
 }
 
-impl<'a, 'tcx> EverInitializedPlaces<'a, 'tcx> {
+impl<'a, 'mir, 'tcx> EverInitializedPlaces<'a, 'mir, 'tcx> {
-    pub fn new(body: &'a Body<'tcx>, mdpe: &'a MoveDataParamEnv<'tcx>) -> Self {
+    pub fn new(body: &'mir Body<'tcx>, mdpe: &'a MoveDataParamEnv<'tcx>) -> Self {
         EverInitializedPlaces { body, mdpe }
     }
 }
 
-impl<'a, 'tcx> HasMoveData<'tcx> for EverInitializedPlaces<'a, 'tcx> {
+impl<'a, 'tcx> HasMoveData<'tcx> for EverInitializedPlaces<'a, '_, 'tcx> {
     fn move_data(&self) -> &MoveData<'tcx> {
         &self.mdpe.move_data
     }
 }
 
-impl<'a, 'tcx> MaybeInitializedPlaces<'a, 'tcx> {
+impl<'a, 'mir, 'tcx> MaybeInitializedPlaces<'a, 'mir, 'tcx> {
     fn update_bits(
         trans: &mut impl GenKill<MovePathIndex>,
         path: MovePathIndex,
@@ -280,7 +288,7 @@ impl<'a, 'tcx> MaybeInitializedPlaces<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx> {
+impl<'a, 'tcx> MaybeUninitializedPlaces<'a, '_, 'tcx> {
     fn update_bits(
         trans: &mut impl GenKill<MovePathIndex>,
         path: MovePathIndex,
@@ -306,7 +314,7 @@ impl<'a, 'tcx> DefinitelyInitializedPlaces<'a, 'tcx> {
     }
 }
 
-impl<'tcx> AnalysisDomain<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
+impl<'tcx> AnalysisDomain<'tcx> for MaybeInitializedPlaces<'_, '_, 'tcx> {
     /// There can be many more `MovePathIndex` than there are locals in a MIR body.
     /// We use a chunked bitset to avoid paying too high a memory footprint.
     type Domain = MaybeReachable<ChunkedBitSet<MovePathIndex>>;
@@ -328,7 +336,7 @@ impl<'tcx> AnalysisDomain<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 }
 
-impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
+impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, '_, 'tcx> {
     type Idx = MovePathIndex;
 
     fn domain_size(&self, _: &Body<'tcx>) -> usize {
@@ -441,7 +449,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 }
 
-impl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
+impl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, '_, 'tcx> {
     /// There can be many more `MovePathIndex` than there are locals in a MIR body.
     /// We use a chunked bitset to avoid paying too high a memory footprint.
     type Domain = ChunkedBitSet<MovePathIndex>;
@@ -465,7 +473,7 @@ impl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 }
 
-impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
+impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, '_, 'tcx> {
     type Idx = MovePathIndex;
 
     fn domain_size(&self, _: &Body<'tcx>) -> usize {
@@ -642,7 +650,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for DefinitelyInitializedPlaces<'_, 'tcx> {
     }
 }
 
-impl<'tcx> AnalysisDomain<'tcx> for EverInitializedPlaces<'_, 'tcx> {
+impl<'tcx> AnalysisDomain<'tcx> for EverInitializedPlaces<'_, '_, 'tcx> {
     /// There can be many more `InitIndex` than there are locals in a MIR body.
     /// We use a chunked bitset to avoid paying too high a memory footprint.
     type Domain = ChunkedBitSet<InitIndex>;
@@ -661,7 +669,7 @@ impl<'tcx> AnalysisDomain<'tcx> for EverInitializedPlaces<'_, 'tcx> {
     }
 }
 
-impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
+impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, '_, 'tcx> {
     type Idx = InitIndex;
 
     fn domain_size(&self, _: &Body<'tcx>) -> usize {

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -97,7 +97,7 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
 #[instrument(level = "trace", skip(body, flow_inits), ret)]
 fn compute_dead_unwinds<'mir, 'tcx>(
     body: &'mir Body<'tcx>,
-    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
+    flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'_, 'mir, 'tcx>>,
 ) -> BitSet<BasicBlock> {
     // We only need to do this pass once, because unwind edges can only
     // reach cleanup blocks, which can't have unwind edges themselves.
@@ -118,12 +118,12 @@ fn compute_dead_unwinds<'mir, 'tcx>(
     dead_unwinds
 }
 
-struct InitializationData<'mir, 'tcx> {
+struct InitializationData<'a, 'mir, 'tcx> {
-    inits: ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
+    inits: ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'a, 'mir, 'tcx>>,
-    uninits: ResultsCursor<'mir, 'tcx, MaybeUninitializedPlaces<'mir, 'tcx>>,
+    uninits: ResultsCursor<'mir, 'tcx, MaybeUninitializedPlaces<'a, 'mir, 'tcx>>,
 }
 
-impl InitializationData<'_, '_> {
+impl InitializationData<'_, '_, '_> {
     fn seek_before(&mut self, loc: Location) {
         self.inits.seek_before_primary_effect(loc);
         self.uninits.seek_before_primary_effect(loc);
@@ -134,17 +134,17 @@ impl InitializationData<'_, '_> {
     }
 }
 
-struct Elaborator<'a, 'b, 'tcx> {
+struct Elaborator<'a, 'b, 'mir, 'tcx> {
-    ctxt: &'a mut ElaborateDropsCtxt<'b, 'tcx>,
+    ctxt: &'a mut ElaborateDropsCtxt<'b, 'mir, 'tcx>,
 }
 
-impl fmt::Debug for Elaborator<'_, '_, '_> {
+impl fmt::Debug for Elaborator<'_, '_, '_, '_> {
     fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Ok(())
     }
 }
 
-impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, 'tcx> {
+impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, '_, 'tcx> {
     type Path = MovePathIndex;
 
     fn patch(&mut self) -> &mut MirPatch<'tcx> {
@@ -238,16 +238,16 @@ impl<'a, 'tcx> DropElaborator<'a, 'tcx> for Elaborator<'a, '_, 'tcx> {
     }
 }
 
-struct ElaborateDropsCtxt<'a, 'tcx> {
+struct ElaborateDropsCtxt<'a, 'mir, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    body: &'a Body<'tcx>,
+    body: &'mir Body<'tcx>,
     env: &'a MoveDataParamEnv<'tcx>,
-    init_data: InitializationData<'a, 'tcx>,
+    init_data: InitializationData<'a, 'mir, 'tcx>,
     drop_flags: IndexVec<MovePathIndex, Option<Local>>,
     patch: MirPatch<'tcx>,
 }
 
-impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
+impl<'b, 'mir, 'tcx> ElaborateDropsCtxt<'b, 'mir, 'tcx> {
     fn move_data(&self) -> &'b MoveData<'tcx> {
         &self.env.move_data
     }

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

@@ -88,7 +88,7 @@ impl<'tcx> InferCtxt<'tcx> {
         found_args: Vec<ArgKind>,
         is_closure: bool,
         closure_arg_span: Option<Span>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'_> {
         let kind = if is_closure { "closure" } else { "function" };
 
         let args_str = |arguments: &[ArgKind], other: &[ArgKind]| {

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

@@ -241,8 +241,8 @@ pub fn suggest_restriction<'tcx, G: EmissionGuarantee>(
     }
 }
 
-#[extension(pub trait TypeErrCtxtExt<'tcx>)]
+#[extension(pub trait TypeErrCtxtExt<'a, 'tcx>)]
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     fn suggest_restricting_param_bound(
         &self,
         err: &mut Diag<'_>,
@@ -1845,7 +1845,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
 
     fn point_at_returns_when_relevant(
         &self,
-        err: &mut Diag<'tcx>,
+        err: &mut Diag<'_>,
         obligation: &PredicateObligation<'tcx>,
     ) {
         match obligation.cause.code().peel_derives() {
@@ -1884,7 +1884,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         cause: &ObligationCauseCode<'tcx>,
         found_node: Option<Node<'_>>,
         param_env: ty::ParamEnv<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         pub(crate) fn build_fn_sig_ty<'tcx>(
             infcx: &InferCtxt<'tcx>,
             trait_ref: ty::TraitRef<'tcx>,
@@ -2104,7 +2104,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
     fn note_conflicting_closure_bounds(
         &self,
         cause: &ObligationCauseCode<'tcx>,
-        err: &mut Diag<'tcx>,
+        err: &mut Diag<'_>,
     ) {
         // First, look for an `WhereClauseInExpr`, which means we can get
         // the uninstantiated predicate list of the called function. And check

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

@@ -82,8 +82,8 @@ pub fn suggest_new_overflow_limit<'tcx, G: EmissionGuarantee>(
     ));
 }
 
-#[extension(pub trait TypeErrCtxtExt<'tcx>)]
+#[extension(pub trait TypeErrCtxtExt<'a, 'tcx>)]
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     fn report_fulfillment_errors(
         &self,
         mut errors: Vec<FulfillmentError<'tcx>>,
@@ -228,7 +228,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         cause: OverflowCause<'tcx>,
         span: Span,
         suggest_increasing_limit: bool,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         fn with_short_path<'tcx, T>(tcx: TyCtxt<'tcx>, value: T) -> String
         where
             T: fmt::Display + Print<'tcx, FmtPrinter<'tcx, 'tcx>>,
@@ -1101,7 +1101,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 && let ty::FnPtr(sig) = by_ref_captures.kind()
                 && !sig.skip_binder().output().is_unit()
             {
-                let mut err = self.tcx.dcx().create_err(AsyncClosureNotFn {
+                let mut err = self.dcx().create_err(AsyncClosureNotFn {
                     span: self.tcx.def_span(closure_def_id),
                     kind: expected_kind.as_str(),
                 });
@@ -1351,7 +1351,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         &self,
         ty: Ty<'tcx>,
         obligation: &PredicateObligation<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let span = obligation.cause.span;
 
         let mut diag = match ty.kind() {
@@ -1445,8 +1445,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
     }
 }
 
-#[extension(pub(super) trait InferCtxtPrivExt<'tcx>)]
+#[extension(pub(super) trait InferCtxtPrivExt<'a, 'tcx>)]
-impl<'tcx> TypeErrCtxt<'_, 'tcx> {
+impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     fn can_match_trait(
         &self,
         goal: ty::TraitPredicate<'tcx>,
@@ -2884,7 +2884,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             self.suggest_unsized_bound_if_applicable(err, obligation);
             if let Some(span) = err.span.primary_span()
                 && let Some(mut diag) =
-                    self.tcx.dcx().steal_non_err(span, StashKey::AssociatedTypeSuggestion)
+                    self.dcx().steal_non_err(span, StashKey::AssociatedTypeSuggestion)
                 && let Ok(ref mut s1) = err.suggestions
                 && let Ok(ref mut s2) = diag.suggestions
             {
@@ -3379,7 +3379,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         found_kind: ty::ClosureKind,
         kind: ty::ClosureKind,
         trait_prefix: &'static str,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let closure_span = self.tcx.def_span(closure_def_id);
 
         let mut err = ClosureKindMismatch {
@@ -3422,7 +3422,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         found_trait_ref: ty::TraitRef<'tcx>,
         expected_trait_ref: ty::TraitRef<'tcx>,
         terr: TypeError<'tcx>,
-    ) -> Diag<'tcx> {
+    ) -> Diag<'a> {
         let self_ty = found_trait_ref.self_ty();
         let (cause, terr) = if let ty::Closure(def_id, _) = self_ty.kind() {
             (
@@ -3473,7 +3473,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         span: Span,
         found_trait_ref: ty::TraitRef<'tcx>,
         expected_trait_ref: ty::TraitRef<'tcx>,
-    ) -> Result<Diag<'tcx>, ErrorGuaranteed> {
+    ) -> Result<Diag<'a>, ErrorGuaranteed> {
         let found_trait_ref = self.resolve_vars_if_possible(found_trait_ref);
         let expected_trait_ref = self.resolve_vars_if_possible(expected_trait_ref);
 
@@ -3553,7 +3553,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     })
                     .unwrap_or((found_span, None, found));
 
-                self.report_arg_count_mismatch(
+                self.infcx.report_arg_count_mismatch(
                     span,
                     closure_span,
                     expected,
@@ -3569,7 +3569,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         &self,
         obligation: &PredicateObligation<'tcx>,
         span: Span,
-    ) -> Result<Diag<'tcx>, ErrorGuaranteed> {
+    ) -> Result<Diag<'a>, ErrorGuaranteed> {
         if !self.tcx.features().generic_const_exprs {
             let guar = self
                 .dcx()

tests/ui/asm/x86_64/type-check-2.rs

@@ -13,13 +13,16 @@ fn main() {
 
         let x: u64;
         asm!("{}", in(reg) x);
+        //~^ ERROR isn't initialized
         let mut y: u64;
         asm!("{}", inout(reg) y);
+        //~^ ERROR isn't initialized
         let _ = y;
 
         // Outputs require mutable places
 
         let v: Vec<u64> = vec![0, 1, 2];
+        //~^ ERROR is not declared as mutable
         asm!("{}", in(reg) v[0]);
         asm!("{}", out(reg) v[0]);
         asm!("{}", inout(reg) v[0]);

tests/ui/asm/x86_64/type-check-2.stderr

@@ -1,5 +1,5 @@
 error: invalid `sym` operand
-  --> $DIR/type-check-2.rs:35:24
+  --> $DIR/type-check-2.rs:38:24
    |
 LL |         asm!("{}", sym x);
    |                        ^ is a local variable
@@ -7,7 +7,7 @@ LL |         asm!("{}", sym x);
    = help: `sym` operands must refer to either a function or a static
 
 error: invalid `sym` operand
-  --> $DIR/type-check-2.rs:86:19
+  --> $DIR/type-check-2.rs:89:19
    |
 LL | global_asm!("{}", sym C);
    |                   ^^^^^ is an `i32`
@@ -15,7 +15,7 @@ LL | global_asm!("{}", sym C);
    = help: `sym` operands must refer to either a function or a static
 
 error: invalid `sym` operand
-  --> $DIR/type-check-2.rs:33:20
+  --> $DIR/type-check-2.rs:36:20
    |
 LL |         asm!("{}", sym C);
    |                    ^^^^^ is an `i32`
@@ -23,15 +23,15 @@ LL |         asm!("{}", sym C);
    = help: `sym` operands must refer to either a function or a static
 
 error: arguments for inline assembly must be copyable
-  --> $DIR/type-check-2.rs:40:32
+  --> $DIR/type-check-2.rs:43:32
    |
 LL |         asm!("{}", in(xmm_reg) SimdNonCopy(0.0, 0.0, 0.0, 0.0));
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `SimdNonCopy` does not implement the Copy trait
 
-error: cannot use value of type `{closure@$DIR/type-check-2.rs:52:28: 52:36}` for inline assembly
+error: cannot use value of type `{closure@$DIR/type-check-2.rs:55:28: 55:36}` for inline assembly
-  --> $DIR/type-check-2.rs:52:28
+  --> $DIR/type-check-2.rs:55:28
    |
 LL |         asm!("{}", in(reg) |x: i32| x);
    |                            ^^^^^^^^^^
@@ -39,7 +39,7 @@ LL |         asm!("{}", in(reg) |x: i32| x);
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `Vec<i32>` for inline assembly
-  --> $DIR/type-check-2.rs:54:28
+  --> $DIR/type-check-2.rs:57:28
    |
 LL |         asm!("{}", in(reg) vec![0]);
    |                            ^^^^^^^
@@ -48,7 +48,7 @@ LL |         asm!("{}", in(reg) vec![0]);
    = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: cannot use value of type `(i32, i32, i32)` for inline assembly
-  --> $DIR/type-check-2.rs:56:28
+  --> $DIR/type-check-2.rs:59:28
    |
 LL |         asm!("{}", in(reg) (1, 2, 3));
    |                            ^^^^^^^^^
@@ -56,7 +56,7 @@ LL |         asm!("{}", in(reg) (1, 2, 3));
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `[i32; 3]` for inline assembly
-  --> $DIR/type-check-2.rs:58:28
+  --> $DIR/type-check-2.rs:61:28
    |
 LL |         asm!("{}", in(reg) [1, 2, 3]);
    |                            ^^^^^^^^^
@@ -64,7 +64,7 @@ LL |         asm!("{}", in(reg) [1, 2, 3]);
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `fn() {main}` for inline assembly
-  --> $DIR/type-check-2.rs:66:31
+  --> $DIR/type-check-2.rs:69:31
    |
 LL |         asm!("{}", inout(reg) f);
    |                               ^
@@ -72,12 +72,56 @@ LL |         asm!("{}", inout(reg) f);
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `&mut i32` for inline assembly
-  --> $DIR/type-check-2.rs:69:31
+  --> $DIR/type-check-2.rs:72:31
    |
 LL |         asm!("{}", inout(reg) r);
    |                               ^
    |
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
-error: aborting due to 10 previous errors
+error[E0381]: used binding `x` isn't initialized
+  --> $DIR/type-check-2.rs:15:28
+   |
+LL |         let x: u64;
+   |             - binding declared here but left uninitialized
+LL |         asm!("{}", in(reg) x);
+   |                            ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let x: u64 = 42;
+   |                    ++++
 
+error[E0381]: used binding `y` isn't initialized
+  --> $DIR/type-check-2.rs:18:9
+   |
+LL |         let mut y: u64;
+   |             ----- binding declared here but left uninitialized
+LL |         asm!("{}", inout(reg) y);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^ `y` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let mut y: u64 = 42;
+   |                        ++++
+
+error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
+  --> $DIR/type-check-2.rs:24:13
+   |
+LL |         let v: Vec<u64> = vec![0, 1, 2];
+   |             ^ not mutable
+...
+LL |         asm!("{}", out(reg) v[0]);
+   |                             - cannot borrow as mutable
+LL |         asm!("{}", inout(reg) v[0]);
+   |                               - cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |         let mut v: Vec<u64> = vec![0, 1, 2];
+   |             +++
+
+error: aborting due to 13 previous errors
+
+Some errors have detailed explanations: E0381, E0596.
+For more information about an error, try `rustc --explain E0381`.

tests/ui/associated-types/associated-types-eq-expr-path.rs

@@ -13,4 +13,5 @@ impl Foo for isize {
 pub fn main() {
     let x: isize = Foo::<A = usize>::bar();
     //~^ ERROR associated item constraints are not allowed here
+    //~| ERROR cannot call
 }

tests/ui/associated-types/associated-types-eq-expr-path.stderr

@@ -4,6 +4,22 @@ error[E0229]: associated item constraints are not allowed here
 LL |     let x: isize = Foo::<A = usize>::bar();
    |                          ^^^^^^^^^ associated item constraint not allowed here
 
-error: aborting due to 1 previous error
+error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
+  --> $DIR/associated-types-eq-expr-path.rs:14:20
+   |
+LL |     fn bar() -> isize;
+   |     ------------------ `Foo::bar` defined here
+...
+LL |     let x: isize = Foo::<A = usize>::bar();
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^ cannot call associated function of trait
+   |
+help: use the fully-qualified path to the only available implementation
+   |
+LL -     let x: isize = Foo::<A = usize>::bar();
+LL +     let x: isize = <isize as Foo<A = usize>>::bar();
+   |
 
-For more information about this error, try `rustc --explain E0229`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0229, E0790.
+For more information about an error, try `rustc --explain E0229`.

tests/ui/const-generics/assoc_const_as_type_argument.rs

@@ -8,6 +8,7 @@ fn foo<T: Trait>() {
     bar::<<T as Trait>::ASSOC>();
     //~^ ERROR: expected associated type, found associated constant `Trait::ASSOC`
     //~| ERROR: unresolved item provided when a constant was expected
+    //~| ERROR type annotations needed
 }
 
 fn main() {}

tests/ui/const-generics/assoc_const_as_type_argument.stderr

@@ -15,7 +15,19 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     bar::<{ <T as Trait>::ASSOC }>();
    |           +                     +
 
-error: aborting due to 2 previous errors
+error[E0284]: type annotations needed
+  --> $DIR/assoc_const_as_type_argument.rs:8:5
+   |
+LL |     bar::<<T as Trait>::ASSOC>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
+   |
+note: required by a const generic parameter in `bar`
+  --> $DIR/assoc_const_as_type_argument.rs:5:8
+   |
+LL | fn bar<const N: usize>() {}
+   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
 
-Some errors have detailed explanations: E0575, E0747.
+error: aborting due to 3 previous errors
-For more information about an error, try `rustc --explain E0575`.
+
+Some errors have detailed explanations: E0284, E0575, E0747.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/const-arg-in-const-arg.min.stderr

@@ -17,7 +17,7 @@ LL |     let _: [u8; bar::<N>()];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:18:23
+  --> $DIR/const-arg-in-const-arg.rs:19:23
    |
 LL |     let _: [u8; faz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -26,7 +26,7 @@ LL |     let _: [u8; faz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:20:23
+  --> $DIR/const-arg-in-const-arg.rs:21:23
    |
 LL |     let _: [u8; baz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -35,7 +35,7 @@ LL |     let _: [u8; baz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:21:23
+  --> $DIR/const-arg-in-const-arg.rs:22:23
    |
 LL |     let _: [u8; faz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -44,7 +44,7 @@ LL |     let _: [u8; faz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:23:23
+  --> $DIR/const-arg-in-const-arg.rs:24:23
    |
 LL |     let _: [u8; baz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -53,7 +53,7 @@ LL |     let _: [u8; baz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:26:23
+  --> $DIR/const-arg-in-const-arg.rs:27:23
    |
 LL |     let _ = [0; bar::<N>()];
    |                       ^ cannot perform const operation using `N`
@@ -62,7 +62,7 @@ LL |     let _ = [0; bar::<N>()];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:28:23
+  --> $DIR/const-arg-in-const-arg.rs:30:23
    |
 LL |     let _ = [0; faz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -71,7 +71,7 @@ LL |     let _ = [0; faz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:30:23
+  --> $DIR/const-arg-in-const-arg.rs:32:23
    |
 LL |     let _ = [0; baz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -80,7 +80,7 @@ LL |     let _ = [0; baz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:31:23
+  --> $DIR/const-arg-in-const-arg.rs:33:23
    |
 LL |     let _ = [0; faz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -89,7 +89,7 @@ LL |     let _ = [0; faz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:33:23
+  --> $DIR/const-arg-in-const-arg.rs:35:23
    |
 LL |     let _ = [0; baz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -98,7 +98,7 @@ LL |     let _ = [0; baz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:34:24
+  --> $DIR/const-arg-in-const-arg.rs:36:24
    |
 LL |     let _: Foo<{ foo::<T>() }>;
    |                        ^ cannot perform const operation using `T`
@@ -107,7 +107,7 @@ LL |     let _: Foo<{ foo::<T>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:35:24
+  --> $DIR/const-arg-in-const-arg.rs:37:24
    |
 LL |     let _: Foo<{ bar::<N>() }>;
    |                        ^ cannot perform const operation using `N`
@@ -116,7 +116,7 @@ LL |     let _: Foo<{ bar::<N>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:37:24
+  --> $DIR/const-arg-in-const-arg.rs:40:24
    |
 LL |     let _: Foo<{ faz::<'a>(&()) }>;
    |                        ^^ cannot perform const operation using `'a`
@@ -125,7 +125,7 @@ LL |     let _: Foo<{ faz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:39:24
+  --> $DIR/const-arg-in-const-arg.rs:42:24
    |
 LL |     let _: Foo<{ baz::<'a>(&()) }>;
    |                        ^^ cannot perform const operation using `'a`
@@ -134,7 +134,7 @@ LL |     let _: Foo<{ baz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:40:24
+  --> $DIR/const-arg-in-const-arg.rs:43:24
    |
 LL |     let _: Foo<{ faz::<'b>(&()) }>;
    |                        ^^ cannot perform const operation using `'b`
@@ -143,7 +143,7 @@ LL |     let _: Foo<{ faz::<'b>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:42:24
+  --> $DIR/const-arg-in-const-arg.rs:45:24
    |
 LL |     let _: Foo<{ baz::<'b>(&()) }>;
    |                        ^^ cannot perform const operation using `'b`
@@ -152,7 +152,7 @@ LL |     let _: Foo<{ baz::<'b>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:43:27
+  --> $DIR/const-arg-in-const-arg.rs:46:27
    |
 LL |     let _ = Foo::<{ foo::<T>() }>;
    |                           ^ cannot perform const operation using `T`
@@ -161,7 +161,7 @@ LL |     let _ = Foo::<{ foo::<T>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:44:27
+  --> $DIR/const-arg-in-const-arg.rs:47:27
    |
 LL |     let _ = Foo::<{ bar::<N>() }>;
    |                           ^ cannot perform const operation using `N`
@@ -170,7 +170,7 @@ LL |     let _ = Foo::<{ bar::<N>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:46:27
+  --> $DIR/const-arg-in-const-arg.rs:50:27
    |
 LL |     let _ = Foo::<{ faz::<'a>(&()) }>;
    |                           ^^ cannot perform const operation using `'a`
@@ -179,7 +179,7 @@ LL |     let _ = Foo::<{ faz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:48:27
+  --> $DIR/const-arg-in-const-arg.rs:52:27
    |
 LL |     let _ = Foo::<{ baz::<'a>(&()) }>;
    |                           ^^ cannot perform const operation using `'a`
@@ -188,7 +188,7 @@ LL |     let _ = Foo::<{ baz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:49:27
+  --> $DIR/const-arg-in-const-arg.rs:53:27
    |
 LL |     let _ = Foo::<{ faz::<'b>(&()) }>;
    |                           ^^ cannot perform const operation using `'b`
@@ -197,7 +197,7 @@ LL |     let _ = Foo::<{ faz::<'b>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:51:27
+  --> $DIR/const-arg-in-const-arg.rs:55:27
    |
 LL |     let _ = Foo::<{ baz::<'b>(&()) }>;
    |                           ^^ cannot perform const operation using `'b`
@@ -216,8 +216,20 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _: [u8; bar::<{ N }>()];
    |                       +   +
 
+error[E0284]: type annotations needed
+  --> $DIR/const-arg-in-const-arg.rs:16:17
+   |
+LL |     let _: [u8; bar::<N>()];
+   |                 ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
+   |
+note: required by a const generic parameter in `bar`
+  --> $DIR/const-arg-in-const-arg.rs:9:14
+   |
+LL | const fn bar<const N: usize>() -> usize { N }
+   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
+
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:18:23
+  --> $DIR/const-arg-in-const-arg.rs:19:23
    |
 LL |     let _: [u8; faz::<'a>(&())];
    |                       ^^
@@ -229,7 +241,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:21:23
+  --> $DIR/const-arg-in-const-arg.rs:22:23
    |
 LL |     let _: [u8; faz::<'b>(&())];
    |                       ^^
@@ -241,7 +253,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0747]: unresolved item provided when a constant was expected
-  --> $DIR/const-arg-in-const-arg.rs:35:24
+  --> $DIR/const-arg-in-const-arg.rs:37:24
    |
 LL |     let _: Foo<{ bar::<N>() }>;
    |                        ^
@@ -251,8 +263,20 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _: Foo<{ bar::<{ N }>() }>;
    |                        +   +
 
+error[E0284]: type annotations needed
+  --> $DIR/const-arg-in-const-arg.rs:37:18
+   |
+LL |     let _: Foo<{ bar::<N>() }>;
+   |                  ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
+   |
+note: required by a const generic parameter in `bar`
+  --> $DIR/const-arg-in-const-arg.rs:9:14
+   |
+LL | const fn bar<const N: usize>() -> usize { N }
+   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
+
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:37:24
+  --> $DIR/const-arg-in-const-arg.rs:40:24
    |
 LL |     let _: Foo<{ faz::<'a>(&()) }>;
    |                        ^^
@@ -264,7 +288,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:40:24
+  --> $DIR/const-arg-in-const-arg.rs:43:24
    |
 LL |     let _: Foo<{ faz::<'b>(&()) }>;
    |                        ^^
@@ -276,7 +300,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error: constant expression depends on a generic parameter
-  --> $DIR/const-arg-in-const-arg.rs:25:17
+  --> $DIR/const-arg-in-const-arg.rs:26:17
    |
 LL |     let _ = [0; foo::<T>()];
    |                 ^^^^^^^^^^
@@ -284,7 +308,7 @@ LL |     let _ = [0; foo::<T>()];
    = note: this may fail depending on what value the parameter takes
 
 error[E0747]: unresolved item provided when a constant was expected
-  --> $DIR/const-arg-in-const-arg.rs:26:23
+  --> $DIR/const-arg-in-const-arg.rs:27:23
    |
 LL |     let _ = [0; bar::<N>()];
    |                       ^
@@ -294,8 +318,20 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _ = [0; bar::<{ N }>()];
    |                       +   +
 
+error[E0284]: type annotations needed
+  --> $DIR/const-arg-in-const-arg.rs:27:17
+   |
+LL |     let _ = [0; bar::<N>()];
+   |                 ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
+   |
+note: required by a const generic parameter in `bar`
+  --> $DIR/const-arg-in-const-arg.rs:9:14
+   |
+LL | const fn bar<const N: usize>() -> usize { N }
+   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
+
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:28:23
+  --> $DIR/const-arg-in-const-arg.rs:30:23
    |
 LL |     let _ = [0; faz::<'a>(&())];
    |                       ^^
@@ -307,7 +343,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:31:23
+  --> $DIR/const-arg-in-const-arg.rs:33:23
    |
 LL |     let _ = [0; faz::<'b>(&())];
    |                       ^^
@@ -319,7 +355,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0747]: unresolved item provided when a constant was expected
-  --> $DIR/const-arg-in-const-arg.rs:44:27
+  --> $DIR/const-arg-in-const-arg.rs:47:27
    |
 LL |     let _ = Foo::<{ bar::<N>() }>;
    |                           ^
@@ -329,8 +365,20 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _ = Foo::<{ bar::<{ N }>() }>;
    |                           +   +
 
+error[E0284]: type annotations needed
+  --> $DIR/const-arg-in-const-arg.rs:47:21
+   |
+LL |     let _ = Foo::<{ bar::<N>() }>;
+   |                     ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
+   |
+note: required by a const generic parameter in `bar`
+  --> $DIR/const-arg-in-const-arg.rs:9:14
+   |
+LL | const fn bar<const N: usize>() -> usize { N }
+   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
+
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:46:27
+  --> $DIR/const-arg-in-const-arg.rs:50:27
    |
 LL |     let _ = Foo::<{ faz::<'a>(&()) }>;
    |                           ^^
@@ -342,7 +390,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:49:27
+  --> $DIR/const-arg-in-const-arg.rs:53:27
    |
 LL |     let _ = Foo::<{ faz::<'b>(&()) }>;
    |                           ^^
@@ -353,7 +401,7 @@ note: the late bound lifetime parameter is introduced here
 LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
-error: aborting due to 36 previous errors
+error: aborting due to 40 previous errors
 
-Some errors have detailed explanations: E0747, E0794.
+Some errors have detailed explanations: E0284, E0747, E0794.
-For more information about an error, try `rustc --explain E0747`.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/const-arg-in-const-arg.rs

@@ -15,6 +15,7 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _: [u8; foo::<T>()]; //[min]~ ERROR generic parameters may not
     let _: [u8; bar::<N>()]; //[min]~ ERROR generic parameters may not
                              //[min]~^ ERROR unresolved item provided when a constant was expected
+                             //[min]~| ERROR type annotations needed
     let _: [u8; faz::<'a>(&())]; //[min]~ ERROR generic parameters may not
                                  //[min]~^ ERROR cannot specify lifetime arguments
     let _: [u8; baz::<'a>(&())]; //[min]~ ERROR generic parameters may not
@@ -25,6 +26,7 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _ = [0; foo::<T>()]; //[min]~ ERROR constant expression depends on a generic parameter
     let _ = [0; bar::<N>()]; //[min]~ ERROR generic parameters may not
                              //[min]~^ ERROR unresolved item provided when a constant was expected
+                             //[min]~| ERROR type annotations needed
     let _ = [0; faz::<'a>(&())]; //[min]~ ERROR generic parameters may not
                                  //[min]~^ ERROR cannot specify lifetime arguments
     let _ = [0; baz::<'a>(&())]; //[min]~ ERROR generic parameters may not
@@ -34,6 +36,7 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _: Foo<{ foo::<T>() }>; //[min]~ ERROR generic parameters may not
     let _: Foo<{ bar::<N>() }>; //[min]~ ERROR generic parameters may not
                                 //[min]~^ ERROR unresolved item provided when a constant was expected
+                                //[min]~| ERROR type annotations needed
     let _: Foo<{ faz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
                                     //[min]~^ ERROR cannot specify lifetime arguments
     let _: Foo<{ baz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
@@ -43,6 +46,7 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _ = Foo::<{ foo::<T>() }>; //[min]~ ERROR generic parameters may not
     let _ = Foo::<{ bar::<N>() }>; //[min]~ ERROR generic parameters may not
                                    //[min]~^ ERROR unresolved item provided when a constant was expected
+                                   //[min]~| ERROR type annotations needed
     let _ = Foo::<{ faz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
                                        //[min]~^ ERROR cannot specify lifetime arguments
     let _ = Foo::<{ baz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not

tests/ui/const-generics/generic_const_exprs/opaque_type.rs

@@ -2,6 +2,7 @@
 #![allow(incomplete_features)]
 
 type Foo = impl Sized;
+//~^ ERROR: unconstrained opaque type
 
 fn with_bound<const N: usize>() -> Foo
 where

tests/ui/const-generics/generic_const_exprs/opaque_type.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/opaque_type.rs:10:17
+  --> $DIR/opaque_type.rs:11:17
    |
 LL | type Foo = impl Sized;
    |            ---------- the found opaque type
@@ -11,12 +11,20 @@ LL |     let _: [u8; (N / 2) as Foo] = [0; (N / 2) as usize];
            found opaque type `Foo`
 
 error[E0605]: non-primitive cast: `usize` as `Foo`
-  --> $DIR/opaque_type.rs:10:17
+  --> $DIR/opaque_type.rs:11:17
    |
 LL |     let _: [u8; (N / 2) as Foo] = [0; (N / 2) as usize];
    |                 ^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
-error: aborting due to 2 previous errors
+error: unconstrained opaque type
+  --> $DIR/opaque_type.rs:4:12
+   |
+LL | type Foo = impl Sized;
+   |            ^^^^^^^^^^
+   |
+   = note: `Foo` must be used in combination with a concrete type within the same module
+
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0308, E0605.
 For more information about an error, try `rustc --explain E0308`.

tests/ui/const-generics/issues/issue-62878.min.stderr

@@ -30,7 +30,31 @@ help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 LL + #![feature(generic_arg_infer)]
    |
 
-error: aborting due to 3 previous errors
+error[E0284]: type annotations needed
+  --> $DIR/issue-62878.rs:10:5
+   |
+LL |     foo::<_, { [1] }>();
+   |     ^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `foo`
+   |
+note: required by a const generic parameter in `foo`
+  --> $DIR/issue-62878.rs:5:8
+   |
+LL | fn foo<const N: usize, const A: [u8; N]>() {}
+   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
 
-Some errors have detailed explanations: E0747, E0770.
+error[E0284]: type annotations needed
-For more information about an error, try `rustc --explain E0747`.
+  --> $DIR/issue-62878.rs:10:5
+   |
+LL |     foo::<_, { [1] }>();
+   |     ^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `A` declared on the function `foo`
+   |
+note: required by a const generic parameter in `foo`
+  --> $DIR/issue-62878.rs:5:24
+   |
+LL | fn foo<const N: usize, const A: [u8; N]>() {}
+   |                        ^^^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0284, E0747, E0770.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/issues/issue-62878.rs

@@ -9,4 +9,6 @@ fn foo<const N: usize, const A: [u8; N]>() {}
 fn main() {
     foo::<_, { [1] }>();
     //[min]~^ ERROR: type provided when a constant was expected
+    //[min]~| ERROR type annotations needed
+    //[min]~| ERROR type annotations needed
 }

tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.rs

@@ -12,6 +12,7 @@ fn b() {
     //~^ ERROR expected trait, found constant `BAR`
     //~| ERROR expected trait, found constant `BAR`
     //~| ERROR type provided when a constant was expected
+    //~| ERROR type annotations needed
 }
 fn c() {
     foo::<3 + 3>(); //~ ERROR expressions must be enclosed in braces

tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.stderr

@@ -10,7 +10,7 @@ LL |     foo::<{ BAR + 3 }>();
    |           +         +
 
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/const-expression-suggest-missing-braces.rs:17:11
+  --> $DIR/const-expression-suggest-missing-braces.rs:18:11
    |
 LL |     foo::<3 + 3>();
    |           ^^^^^
@@ -21,7 +21,7 @@ LL |     foo::<{ 3 + 3 }>();
    |           +       +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:20:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:21:15
    |
 LL |     foo::<BAR - 3>();
    |               ^ expected one of `,` or `>`
@@ -32,7 +32,7 @@ LL |     foo::<{ BAR - 3 }>();
    |           +         +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:23:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:24:15
    |
 LL |     foo::<BAR - BAR>();
    |               ^ expected one of `,` or `>`
@@ -43,7 +43,7 @@ LL |     foo::<{ BAR - BAR }>();
    |           +           +
 
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/const-expression-suggest-missing-braces.rs:26:11
+  --> $DIR/const-expression-suggest-missing-braces.rs:27:11
    |
 LL |     foo::<100 - BAR>();
    |           ^^^^^^^^^
@@ -54,7 +54,7 @@ LL |     foo::<{ 100 - BAR }>();
    |           +           +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:29:19
+  --> $DIR/const-expression-suggest-missing-braces.rs:30:19
    |
 LL |     foo::<bar<i32>()>();
    |                   ^ expected one of `,` or `>`
@@ -65,7 +65,7 @@ LL |     foo::<{ bar<i32>() }>();
    |           +            +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:32:21
+  --> $DIR/const-expression-suggest-missing-braces.rs:33:21
    |
 LL |     foo::<bar::<i32>()>();
    |                     ^ expected one of `,` or `>`
@@ -76,7 +76,7 @@ LL |     foo::<{ bar::<i32>() }>();
    |           +              +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:35:21
+  --> $DIR/const-expression-suggest-missing-braces.rs:36:21
    |
 LL |     foo::<bar::<i32>() + BAR>();
    |                     ^ expected one of `,` or `>`
@@ -87,7 +87,7 @@ LL |     foo::<{ bar::<i32>() + BAR }>();
    |           +                    +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:38:21
+  --> $DIR/const-expression-suggest-missing-braces.rs:39:21
    |
 LL |     foo::<bar::<i32>() - BAR>();
    |                     ^ expected one of `,` or `>`
@@ -98,7 +98,7 @@ LL |     foo::<{ bar::<i32>() - BAR }>();
    |           +                    +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:41:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:42:15
    |
 LL |     foo::<BAR - bar::<i32>()>();
    |               ^ expected one of `,` or `>`
@@ -109,7 +109,7 @@ LL |     foo::<{ BAR - bar::<i32>() }>();
    |           +                    +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:44:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:45:15
    |
 LL |     foo::<BAR - bar::<i32>()>();
    |               ^ expected one of `,` or `>`
@@ -137,7 +137,19 @@ error[E0747]: type provided when a constant was expected
 LL |     foo::<BAR + BAR>();
    |           ^^^^^^^^^
 
-error: aborting due to 14 previous errors
+error[E0284]: type annotations needed
+  --> $DIR/const-expression-suggest-missing-braces.rs:11:5
+   |
+LL |     foo::<BAR + BAR>();
+   |     ^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `C` declared on the function `foo`
+   |
+note: required by a const generic parameter in `foo`
+  --> $DIR/const-expression-suggest-missing-braces.rs:1:8
+   |
+LL | fn foo<const C: usize>() {}
+   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
 
-Some errors have detailed explanations: E0404, E0747.
+error: aborting due to 15 previous errors
-For more information about an error, try `rustc --explain E0404`.
+
+Some errors have detailed explanations: E0284, E0404, E0747.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/min_const_generics/macro-fail.rs

@@ -16,6 +16,7 @@ fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
   //~| ERROR: type provided when a constant was expected
   Example::<gimme_a_const!(marker)>
   //~^ ERROR: type provided when a constant was expected
+  //~| ERROR type annotations needed
 }
 
 fn from_marker(_: impl Marker<{
@@ -35,9 +36,11 @@ fn main() {
   }>;
 
   let _fail = Example::<external_macro!()>;
-  //~^ ERROR: type provided when a constant was expected
+  //~^ ERROR: type provided when a constant
+  //~| ERROR type annotations needed
 
   let _fail = Example::<gimme_a_const!()>;
   //~^ ERROR unexpected end of macro invocation
   //~| ERROR: type provided when a constant was expected
+  //~| ERROR type annotations needed
 }

tests/ui/const-generics/min_const_generics/macro-fail.stderr

@@ -1,5 +1,5 @@
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:30:27
+  --> $DIR/macro-fail.rs:31:27
    |
 LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
    |                                 ----------------------
@@ -13,7 +13,7 @@ LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:30:27
+  --> $DIR/macro-fail.rs:31:27
    |
 LL |   Example::<gimme_a_const!(marker)>
    |             ----------------------
@@ -41,7 +41,7 @@ LL |   let _fail = Example::<external_macro!()>;
    = note: this error originates in the macro `external_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: unexpected end of macro invocation
-  --> $DIR/macro-fail.rs:40:25
+  --> $DIR/macro-fail.rs:42:25
    |
 LL |     macro_rules! gimme_a_const {
    |     -------------------------- when calling this macro
@@ -50,7 +50,7 @@ LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^ missing tokens in macro arguments
    |
 note: while trying to match meta-variable `$rusty:ident`
-  --> $DIR/macro-fail.rs:30:8
+  --> $DIR/macro-fail.rs:31:8
    |
 LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    |        ^^^^^^^^^^^^^
@@ -75,18 +75,63 @@ error[E0747]: type provided when a constant was expected
 LL |   Example::<gimme_a_const!(marker)>
    |             ^^^^^^^^^^^^^^^^^^^^^^
 
+error[E0284]: type annotations needed
+  --> $DIR/macro-fail.rs:17:3
+   |
+LL |   Example::<gimme_a_const!(marker)>
+   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the struct `Example`
+   |
+note: required by a const generic parameter in `Example`
+  --> $DIR/macro-fail.rs:1:16
+   |
+LL | struct Example<const N: usize>;
+   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
+
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:37:25
+  --> $DIR/macro-fail.rs:38:25
    |
 LL |   let _fail = Example::<external_macro!()>;
    |                         ^^^^^^^^^^^^^^^^^
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:40:25
+  --> $DIR/macro-fail.rs:42:25
    |
 LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^
 
-error: aborting due to 9 previous errors
+error[E0284]: type annotations needed for `Example<_>`
+  --> $DIR/macro-fail.rs:38:7
+   |
+LL |   let _fail = Example::<external_macro!()>;
+   |       ^^^^^   ---------------------------- type must be known at this point
+   |
+note: required by a const generic parameter in `Example`
+  --> $DIR/macro-fail.rs:1:16
+   |
+LL | struct Example<const N: usize>;
+   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
+help: consider giving `_fail` an explicit type, where the value of const parameter `N` is specified
+   |
+LL |   let _fail: Example<N> = Example::<external_macro!()>;
+   |            ++++++++++++
 
-For more information about this error, try `rustc --explain E0747`.
+error[E0284]: type annotations needed for `Example<_>`
+  --> $DIR/macro-fail.rs:42:7
+   |
+LL |   let _fail = Example::<gimme_a_const!()>;
+   |       ^^^^^   --------------------------- type must be known at this point
+   |
+note: required by a const generic parameter in `Example`
+  --> $DIR/macro-fail.rs:1:16
+   |
+LL | struct Example<const N: usize>;
+   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
+help: consider giving `_fail` an explicit type, where the value of const parameter `N` is specified
+   |
+LL |   let _fail: Example<N> = Example::<gimme_a_const!()>;
+   |            ++++++++++++
+
+error: aborting due to 12 previous errors
+
+Some errors have detailed explanations: E0284, E0747.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/suggest_const_for_array.rs

@@ -5,6 +5,8 @@ fn example<const N: usize>() {}
 fn other() {
     example::<[usize; 3]>();
     //~^ ERROR type provided when a const
-  example::<[usize; 4+5]>();
+    //~| ERROR type annotations needed
+    example::<[usize; 4 + 5]>();
     //~^ ERROR type provided when a const
+    //~| ERROR type annotations needed
 }

tests/ui/const-generics/suggest_const_for_array.stderr

@@ -1,15 +1,40 @@
 error[E0747]: type provided when a constant was expected
-  --> $DIR/suggest_const_for_array.rs:6:13
+  --> $DIR/suggest_const_for_array.rs:6:15
    |
 LL |     example::<[usize; 3]>();
    |               ^^^^^^^^^^ help: array type provided where a `usize` was expected, try: `{ 3 }`
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/suggest_const_for_array.rs:8:13
+  --> $DIR/suggest_const_for_array.rs:9:15
    |
-LL |   example::<[usize; 4+5]>();
+LL |     example::<[usize; 4 + 5]>();
-   |             ^^^^^^^^^^^^ help: array type provided where a `usize` was expected, try: `{ 4+5 }`
+   |               ^^^^^^^^^^^^^^ help: array type provided where a `usize` was expected, try: `{ 4 + 5 }`
 
-error: aborting due to 2 previous errors
+error[E0284]: type annotations needed
+  --> $DIR/suggest_const_for_array.rs:6:5
+   |
+LL |     example::<[usize; 3]>();
+   |     ^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `example`
+   |
+note: required by a const generic parameter in `example`
+  --> $DIR/suggest_const_for_array.rs:3:12
+   |
+LL | fn example<const N: usize>() {}
+   |            ^^^^^^^^^^^^^^ required by this const generic parameter in `example`
 
-For more information about this error, try `rustc --explain E0747`.
+error[E0284]: type annotations needed
+  --> $DIR/suggest_const_for_array.rs:9:5
+   |
+LL |     example::<[usize; 4 + 5]>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `example`
+   |
+note: required by a const generic parameter in `example`
+  --> $DIR/suggest_const_for_array.rs:3:12
+   |
+LL | fn example<const N: usize>() {}
+   |            ^^^^^^^^^^^^^^ required by this const generic parameter in `example`
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0284, E0747.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/generics/generic-function-item-where-type.rs

@@ -3,4 +3,5 @@ fn foo<U>() {}
 fn main() {
     foo::<main>()
     //~^ ERROR constant provided when a type was expected
+    //~| ERROR type annotations needed
 }

tests/ui/generics/generic-function-item-where-type.stderr

@@ -7,6 +7,13 @@ LL |     foo::<main>()
    = help: `main` is a function item, not a type
    = help: function item types cannot be named directly
 
-error: aborting due to 1 previous error
+error[E0282]: type annotations needed
+  --> $DIR/generic-function-item-where-type.rs:4:5
+   |
+LL |     foo::<main>()
+   |     ^^^^^^^^^^^ cannot infer type of the type parameter `U` declared on the function `foo`
 
-For more information about this error, try `rustc --explain E0747`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0282, E0747.
+For more information about an error, try `rustc --explain E0282`.

tests/ui/impl-trait/impl-fn-predefined-lifetimes.rs

@@ -2,6 +2,7 @@
 use std::fmt::Debug;
 
 fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
+    //~^ ERROR cannot resolve opaque type
     |x| x
     //~^ ERROR expected generic lifetime parameter, found `'_`
 }

tests/ui/impl-trait/impl-fn-predefined-lifetimes.stderr

@@ -1,11 +1,19 @@
 error[E0792]: expected generic lifetime parameter, found `'_`
-  --> $DIR/impl-fn-predefined-lifetimes.rs:5:9
+  --> $DIR/impl-fn-predefined-lifetimes.rs:6:9
    |
 LL | fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
    |                                                -- this generic parameter must be used with a generic lifetime parameter
+LL |
 LL |     |x| x
    |         ^
 
-error: aborting due to 1 previous error
+error[E0720]: cannot resolve opaque type
+  --> $DIR/impl-fn-predefined-lifetimes.rs:4:35
+   |
+LL | fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) {
+   |                                   ^^^^^^^^^^^^^^^ cannot resolve opaque type
 
-For more information about this error, try `rustc --explain E0792`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0720, E0792.
+For more information about an error, try `rustc --explain E0720`.

tests/ui/impl-trait/transmute/in-defining-scope.rs

@@ -5,6 +5,7 @@
 use std::mem::transmute;
 fn foo() -> impl Sized {
     //~^ ERROR cycle detected when computing type of
+    //~| WARN function cannot return without recursing
     unsafe {
         transmute::<_, u8>(foo());
     }

tests/ui/impl-trait/transmute/in-defining-scope.stderr

@@ -24,6 +24,18 @@ LL | fn foo() -> impl Sized {
    |             ^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error: aborting due to 1 previous error
+warning: function cannot return without recursing
+  --> $DIR/in-defining-scope.rs:6:1
+   |
+LL | fn foo() -> impl Sized {
+   | ^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
+...
+LL |         transmute::<_, u8>(foo());
+   |                            ----- recursive call site
+   |
+   = help: a `loop` may express intention better if this is on purpose
+   = note: `#[warn(unconditional_recursion)]` on by default
+
+error: aborting due to 1 previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0391`.

tests/ui/infinite/infinite-struct.rs

@@ -1,5 +1,6 @@
 struct Take(Take);
 //~^ ERROR has infinite size
+//~| ERROR cycle
 
 // check that we don't hang trying to find the tail of a recursive struct (#79437)
 fn foo() -> Take {

tests/ui/infinite/infinite-struct.stderr

@@ -10,7 +10,7 @@ LL | struct Take(Box<Take>);
    |             ++++    +
 
 error[E0072]: recursive type `Foo` has infinite size
-  --> $DIR/infinite-struct.rs:10:1
+  --> $DIR/infinite-struct.rs:11:1
    |
 LL | struct Foo {
    | ^^^^^^^^^^
@@ -26,6 +26,17 @@ error: reached the recursion limit finding the struct tail for `Take`
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]`
 
-error: aborting due to 3 previous errors
+error[E0391]: cycle detected when computing when `Take` needs drop
+  --> $DIR/infinite-struct.rs:1:1
+   |
+LL | struct Take(Take);
+   | ^^^^^^^^^^^
+   |
+   = note: ...which immediately requires computing when `Take` needs drop again
+   = note: cycle used when computing whether `Take` needs drop
+   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-For more information about this error, try `rustc --explain E0072`.
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0072, E0391.
+For more information about an error, try `rustc --explain E0072`.

tests/ui/static/reference-of-mut-static-unsafe-fn.rs

@@ -1,26 +0,0 @@
-//@ compile-flags: --edition 2024 -Z unstable-options
-
-fn main() {}
-
-unsafe fn _foo() {
-    static mut X: i32 = 1;
-    static mut Y: i32 = 1;
-
-    let _y = &X;
-    //~^ ERROR creating a shared reference to a mutable static [E0796]
-
-    let ref _a = X;
-    //~^ ERROR creating a shared reference to a mutable static [E0796]
-
-    let ref mut _a = X;
-    //~^ ERROR creating a mutable reference to a mutable static [E0796]
-
-    let (_b, _c) = (&X, &mut Y);
-    //~^ ERROR creating a shared reference to a mutable static [E0796]
-    //~^^ ERROR creating a mutable reference to a mutable static [E0796]
-
-    foo(&X);
-    //~^ ERROR creating a shared reference to a mutable static [E0796]
-}
-
-fn foo<'a>(_x: &'a i32) {}

tests/ui/static/reference-of-mut-static-unsafe-fn.stderr

@@ -1,75 +0,0 @@
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static-unsafe-fn.rs:9:14
-   |
-LL |     let _y = &X;
-   |              ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |     let _y = addr_of!(X);
-   |              ~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static-unsafe-fn.rs:12:18
-   |
-LL |     let ref _a = X;
-   |                  ^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |     let ref _a = addr_of!(X);
-   |                  ~~~~~~~~~~~
-
-error[E0796]: creating a mutable reference to a mutable static
-  --> $DIR/reference-of-mut-static-unsafe-fn.rs:15:22
-   |
-LL |     let ref mut _a = X;
-   |                      ^ mutable reference to mutable static
-   |
-   = note: this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
-help: use `addr_of_mut!` instead to create a raw pointer
-   |
-LL |     let ref mut _a = addr_of_mut!(X);
-   |                      ~~~~~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static-unsafe-fn.rs:18:21
-   |
-LL |     let (_b, _c) = (&X, &mut Y);
-   |                     ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |     let (_b, _c) = (addr_of!(X), &mut Y);
-   |                     ~~~~~~~~~~~
-
-error[E0796]: creating a mutable reference to a mutable static
-  --> $DIR/reference-of-mut-static-unsafe-fn.rs:18:25
-   |
-LL |     let (_b, _c) = (&X, &mut Y);
-   |                         ^^^^^^ mutable reference to mutable static
-   |
-   = note: this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
-help: use `addr_of_mut!` instead to create a raw pointer
-   |
-LL |     let (_b, _c) = (&X, addr_of_mut!(Y));
-   |                         ~~~~~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static-unsafe-fn.rs:22:9
-   |
-LL |     foo(&X);
-   |         ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |     foo(addr_of!(X));
-   |         ~~~~~~~~~~~
-
-error: aborting due to 6 previous errors
-
-For more information about this error, try `rustc --explain E0796`.

tests/ui/static/reference-of-mut-static.e2021.stderr

@@ -1,91 +0,0 @@
-error: creating a shared reference to mutable static is discouraged
-  --> $DIR/reference-of-mut-static.rs:16:18
-   |
-LL |         let _y = &X;
-   |                  ^^ shared reference to mutable static
-   |
-   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
-   = note: this will be a hard error in the 2024 edition
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-note: the lint level is defined here
-  --> $DIR/reference-of-mut-static.rs:6:9
-   |
-LL | #![deny(static_mut_refs)]
-   |         ^^^^^^^^^^^^^^^
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let _y = addr_of!(X);
-   |                  ~~~~~~~~~~~
-
-error: creating a mutable reference to mutable static is discouraged
-  --> $DIR/reference-of-mut-static.rs:20:18
-   |
-LL |         let _y = &mut X;
-   |                  ^^^^^^ mutable reference to mutable static
-   |
-   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
-   = note: this will be a hard error in the 2024 edition
-   = note: this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
-help: use `addr_of_mut!` instead to create a raw pointer
-   |
-LL |         let _y = addr_of_mut!(X);
-   |                  ~~~~~~~~~~~~~~~
-
-error: creating a shared reference to mutable static is discouraged
-  --> $DIR/reference-of-mut-static.rs:28:22
-   |
-LL |         let ref _a = X;
-   |                      ^ shared reference to mutable static
-   |
-   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
-   = note: this will be a hard error in the 2024 edition
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let ref _a = addr_of!(X);
-   |                      ~~~~~~~~~~~
-
-error: creating a shared reference to mutable static is discouraged
-  --> $DIR/reference-of-mut-static.rs:32:25
-   |
-LL |         let (_b, _c) = (&X, &Y);
-   |                         ^^ shared reference to mutable static
-   |
-   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
-   = note: this will be a hard error in the 2024 edition
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let (_b, _c) = (addr_of!(X), &Y);
-   |                         ~~~~~~~~~~~
-
-error: creating a shared reference to mutable static is discouraged
-  --> $DIR/reference-of-mut-static.rs:32:29
-   |
-LL |         let (_b, _c) = (&X, &Y);
-   |                             ^^ shared reference to mutable static
-   |
-   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
-   = note: this will be a hard error in the 2024 edition
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let (_b, _c) = (&X, addr_of!(Y));
-   |                             ~~~~~~~~~~~
-
-error: creating a shared reference to mutable static is discouraged
-  --> $DIR/reference-of-mut-static.rs:38:13
-   |
-LL |         foo(&X);
-   |             ^^ shared reference to mutable static
-   |
-   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
-   = note: this will be a hard error in the 2024 edition
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         foo(addr_of!(X));
-   |             ~~~~~~~~~~~
-
-error: aborting due to 6 previous errors
-

tests/ui/static/reference-of-mut-static.e2024.stderr

@@ -1,75 +0,0 @@
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static.rs:16:18
-   |
-LL |         let _y = &X;
-   |                  ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let _y = addr_of!(X);
-   |                  ~~~~~~~~~~~
-
-error[E0796]: creating a mutable reference to a mutable static
-  --> $DIR/reference-of-mut-static.rs:20:18
-   |
-LL |         let _y = &mut X;
-   |                  ^^^^^^ mutable reference to mutable static
-   |
-   = note: this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
-help: use `addr_of_mut!` instead to create a raw pointer
-   |
-LL |         let _y = addr_of_mut!(X);
-   |                  ~~~~~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static.rs:28:22
-   |
-LL |         let ref _a = X;
-   |                      ^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let ref _a = addr_of!(X);
-   |                      ~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static.rs:32:25
-   |
-LL |         let (_b, _c) = (&X, &Y);
-   |                         ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let (_b, _c) = (addr_of!(X), &Y);
-   |                         ~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static.rs:32:29
-   |
-LL |         let (_b, _c) = (&X, &Y);
-   |                             ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         let (_b, _c) = (&X, addr_of!(Y));
-   |                             ~~~~~~~~~~~
-
-error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-of-mut-static.rs:38:13
-   |
-LL |         foo(&X);
-   |             ^^ shared reference to mutable static
-   |
-   = note: this shared reference has lifetime `'static`, but if the static ever gets mutated, or a mutable reference is created, then any further use of this shared reference is Undefined Behavior
-help: use `addr_of!` instead to create a raw pointer
-   |
-LL |         foo(addr_of!(X));
-   |             ~~~~~~~~~~~
-
-error: aborting due to 6 previous errors
-
-For more information about this error, try `rustc --explain E0796`.

tests/ui/static/reference-of-mut-static.rs

@@ -1,50 +0,0 @@
-//@ revisions: e2021 e2024
-
-//@ [e2021] edition:2021
-//@ [e2024] compile-flags: --edition 2024 -Z unstable-options
-
-#![deny(static_mut_refs)]
-
-use std::ptr::{addr_of, addr_of_mut};
-
-fn main() {
-    static mut X: i32 = 1;
-
-    static mut Y: i32 = 1;
-
-    unsafe {
-        let _y = &X;
-        //[e2024]~^ ERROR creating a shared reference to a mutable static [E0796]
-        //[e2021]~^^ ERROR shared reference to mutable static is discouraged [static_mut_refs]
-
-        let _y = &mut X;
-        //[e2024]~^ ERROR creating a mutable reference to a mutable static [E0796]
-        //[e2021]~^^ ERROR mutable reference to mutable static is discouraged [static_mut_refs]
-
-        let _z = addr_of_mut!(X);
-
-        let _p = addr_of!(X);
-
-        let ref _a = X;
-        //[e2024]~^ ERROR creating a shared reference to a mutable static [E0796]
-        //[e2021]~^^ ERROR shared reference to mutable static is discouraged [static_mut_refs]
-
-        let (_b, _c) = (&X, &Y);
-        //[e2024]~^ ERROR creating a shared reference to a mutable static [E0796]
-        //[e2021]~^^ ERROR shared reference to mutable static is discouraged [static_mut_refs]
-        //[e2024]~^^^ ERROR creating a shared reference to a mutable static [E0796]
-        //[e2021]~^^^^ ERROR shared reference to mutable static is discouraged [static_mut_refs]
-
-        foo(&X);
-        //[e2024]~^ ERROR creating a shared reference to a mutable static [E0796]
-        //[e2021]~^^ ERROR shared reference to mutable static is discouraged [static_mut_refs]
-
-        static mut Z: &[i32; 3] = &[0, 1, 2];
-
-        let _ = Z.len();
-        let _ = Z[0];
-        let _ = format!("{:?}", Z);
-    }
-}
-
-fn foo<'a>(_x: &'a i32) {}

tests/ui/static/reference-to-mut-static-safe.e2024.stderr

@@ -10,6 +10,15 @@ help: use `addr_of!` instead to create a raw pointer
 LL |     let _x = addr_of!(X);
    |              ~~~~~~~~~~~
 
-error: aborting due to 1 previous error
+error[E0133]: use of mutable static is unsafe and requires unsafe block
+  --> $DIR/reference-to-mut-static-safe.rs:9:15
+   |
+LL |     let _x = &X;
+   |               ^ use of mutable static
+   |
+   = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior
 
-For more information about this error, try `rustc --explain E0796`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0133, E0796.
+For more information about an error, try `rustc --explain E0133`.

tests/ui/static/reference-to-mut-static-safe.rs

@@ -8,6 +8,6 @@ fn main() {
 
     let _x = &X;
     //[e2024]~^ creating a shared reference to a mutable static [E0796]
-    //[e2021]~^^ use of mutable static is unsafe and requires unsafe function or block [E0133]
+    //~^^ use of mutable static is unsafe and requires unsafe
     //[e2021]~^^^ shared reference to mutable static is discouraged [static_mut_refs]
 }

tests/ui/static/reference-to-mut-static-unsafe-fn.rs

@@ -3,6 +3,7 @@
 fn main() {}
 
 unsafe fn _foo() {
+    unsafe {
         static mut X: i32 = 1;
         static mut Y: i32 = 1;
 
@@ -21,6 +22,7 @@ unsafe fn _foo() {
 
         foo(&X);
         //~^ ERROR creating a shared reference to a mutable static [E0796]
+    }
 }
 
 fn foo<'a>(_x: &'a i32) {}

tests/ui/static/reference-to-mut-static-unsafe-fn.stderr

@@ -1,5 +1,5 @@
 error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-to-mut-static-unsafe-fn.rs:9:14
+  --> $DIR/reference-to-mut-static-unsafe-fn.rs:10:18
    |
 LL |         let _y = &X;
    |                  ^^ shared reference to mutable static
@@ -11,7 +11,7 @@ LL |     let _y = addr_of!(X);
    |                  ~~~~~~~~~~~
 
 error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-to-mut-static-unsafe-fn.rs:12:18
+  --> $DIR/reference-to-mut-static-unsafe-fn.rs:13:22
    |
 LL |         let ref _a = X;
    |                      ^ shared reference to mutable static
@@ -23,7 +23,7 @@ LL |     let ref _a = addr_of!(X);
    |                      ~~~~~~~~~~~
 
 error[E0796]: creating a mutable reference to a mutable static
-  --> $DIR/reference-to-mut-static-unsafe-fn.rs:15:22
+  --> $DIR/reference-to-mut-static-unsafe-fn.rs:16:26
    |
 LL |         let ref mut _a = X;
    |                          ^ mutable reference to mutable static
@@ -35,7 +35,7 @@ LL |     let ref mut _a = addr_of_mut!(X);
    |                          ~~~~~~~~~~~~~~~
 
 error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-to-mut-static-unsafe-fn.rs:18:21
+  --> $DIR/reference-to-mut-static-unsafe-fn.rs:19:25
    |
 LL |         let (_b, _c) = (&X, &mut Y);
    |                         ^^ shared reference to mutable static
@@ -47,7 +47,7 @@ LL |     let (_b, _c) = (addr_of!(X), &mut Y);
    |                         ~~~~~~~~~~~
 
 error[E0796]: creating a mutable reference to a mutable static
-  --> $DIR/reference-to-mut-static-unsafe-fn.rs:18:25
+  --> $DIR/reference-to-mut-static-unsafe-fn.rs:19:29
    |
 LL |         let (_b, _c) = (&X, &mut Y);
    |                             ^^^^^^ mutable reference to mutable static
@@ -59,7 +59,7 @@ LL |     let (_b, _c) = (&X, addr_of_mut!(Y));
    |                             ~~~~~~~~~~~~~~~
 
 error[E0796]: creating a shared reference to a mutable static
-  --> $DIR/reference-to-mut-static-unsafe-fn.rs:22:9
+  --> $DIR/reference-to-mut-static-unsafe-fn.rs:23:13
    |
 LL |         foo(&X);
    |             ^^ shared reference to mutable static

tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr

@@ -44,18 +44,6 @@ LL |
 LL |     call(operation).await
    |     ^^^^^^^^^^^^^^^
 
-error[E0792]: expected generic lifetime parameter, found `'any`
-  --> $DIR/hkl_forbidden4.rs:23:1
-   |
-LL |   type FutNothing<'a> = impl 'a + Future<Output = ()>;
-   |                   -- this generic parameter must be used with a generic lifetime parameter
-...
-LL | / {
-LL | |
-LL | |
-LL | | }
-   | |_^
-
 error: concrete type differs from previous defining opaque type use
   --> $DIR/hkl_forbidden4.rs:13:1
    |
@@ -68,6 +56,18 @@ note: previous use here
 LL |     call(operation).await
    |     ^^^^^^^^^^^^^^^
 
+error[E0792]: expected generic lifetime parameter, found `'any`
+  --> $DIR/hkl_forbidden4.rs:23:1
+   |
+LL |   type FutNothing<'a> = impl 'a + Future<Output = ()>;
+   |                   -- this generic parameter must be used with a generic lifetime parameter
+...
+LL | / {
+LL | |
+LL | |
+LL | | }
+   | |_^
+
 error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0792`.

tests/ui/type-alias-impl-trait/issue-53092-2.rs

@@ -5,6 +5,8 @@ type Bug<T, U> = impl Fn(T) -> U + Copy; //~ ERROR cycle detected
 
 const CONST_BUG: Bug<u8, ()> = unsafe { std::mem::transmute(|_: u8| ()) };
 //~^ ERROR: non-defining opaque type use
+//~| ERROR: item does not constrain
+//~| ERROR: item does not constrain
 
 fn make_bug<T, U: From<T>>() -> Bug<T, U> {
     |x| x.into() //~ ERROR the trait bound `U: From<T>` is not satisfied

tests/ui/type-alias-impl-trait/issue-53092-2.stderr

@@ -36,14 +36,40 @@ LL | type Bug<T, U> = impl Fn(T) -> U + Copy;
    |                  ^^^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
+error: item does not constrain `Bug::{opaque#0}`, but has it in its signature
+  --> $DIR/issue-53092-2.rs:6:7
+   |
+LL | const CONST_BUG: Bug<u8, ()> = unsafe { std::mem::transmute(|_: u8| ()) };
+   |       ^^^^^^^^^
+   |
+   = note: consider moving the opaque type's declaration and defining uses into a separate module
+note: this opaque type is in the signature
+  --> $DIR/issue-53092-2.rs:4:18
+   |
+LL | type Bug<T, U> = impl Fn(T) -> U + Copy;
+   |                  ^^^^^^^^^^^^^^^^^^^^^^
+
+error: item does not constrain `Bug::{opaque#0}`, but has it in its signature
+  --> $DIR/issue-53092-2.rs:6:61
+   |
+LL | const CONST_BUG: Bug<u8, ()> = unsafe { std::mem::transmute(|_: u8| ()) };
+   |                                                             ^^^^^^^
+   |
+   = note: consider moving the opaque type's declaration and defining uses into a separate module
+note: this opaque type is in the signature
+  --> $DIR/issue-53092-2.rs:4:18
+   |
+LL | type Bug<T, U> = impl Fn(T) -> U + Copy;
+   |                  ^^^^^^^^^^^^^^^^^^^^^^
+
 error[E0277]: the trait bound `U: From<T>` is not satisfied
-  --> $DIR/issue-53092-2.rs:10:5
+  --> $DIR/issue-53092-2.rs:12:5
    |
 LL |     |x| x.into()
    |     ^^^^^^^^^^^^ the trait `From<T>` is not implemented for `U`
    |
 note: required by a bound in `make_bug`
-  --> $DIR/issue-53092-2.rs:9:19
+  --> $DIR/issue-53092-2.rs:11:19
    |
 LL | fn make_bug<T, U: From<T>>() -> Bug<T, U> {
    |                   ^^^^^^^ required by this bound in `make_bug`
@@ -52,7 +78,7 @@ help: consider restricting type parameter `U`
 LL | type Bug<T, U: std::convert::From<T>> = impl Fn(T) -> U + Copy;
    |              +++++++++++++++++++++++
 
-error: aborting due to 3 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0277, E0391, E0792.
 For more information about an error, try `rustc --explain E0277`.