diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index f32ff57fe88b9..8200a58f31fff 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -2888,7 +2888,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             ..
         } = explanation
         {
-            if let Some(diag) = self.try_report_cannot_return_reference_to_local(
+            if let Err(diag) = self.try_report_cannot_return_reference_to_local(
                 borrow,
                 borrow_span,
                 span,
@@ -3075,7 +3075,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         if let BorrowExplanation::MustBeValidFor { category, span, from_closure: false, .. } =
             explanation
         {
-            if let Some(diag) = self.try_report_cannot_return_reference_to_local(
+            if let Err(diag) = self.try_report_cannot_return_reference_to_local(
                 borrow,
                 proper_span,
                 span,
@@ -3237,11 +3237,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         return_span: Span,
         category: ConstraintCategory<'tcx>,
         opt_place_desc: Option<&String>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Result<(), Diag<'tcx>> {
         let return_kind = match category {
             ConstraintCategory::Return(_) => "return",
             ConstraintCategory::Yield => "yield",
-            _ => return None,
+            _ => return Ok(()),
         };
 
         // FIXME use a better heuristic than Spans
@@ -3317,7 +3317,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             }
         }
 
-        Some(err)
+        Err(err)
     }
 
     #[instrument(level = "debug", skip(self))]
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index 9736c8b89204e..93222c1868651 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -628,7 +628,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return;
             };
 
-            let pick = self.confirm_method(
+            let pick = self.confirm_method_for_diagnostic(
                 call_expr.span,
                 callee_expr,
                 call_expr,
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs
index d2a5924c8bbb9..f9720c9c30795 100644
--- a/compiler/rustc_hir_typeck/src/demand.rs
+++ b/compiler/rustc_hir_typeck/src/demand.rs
@@ -4,7 +4,7 @@ use rustc_errors::{Applicability, Diag};
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::intravisit::Visitor;
-use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
+use rustc_infer::infer::DefineOpaqueTypes;
 use rustc_middle::bug;
 use rustc_middle::ty::adjustment::AllowTwoPhase;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -166,7 +166,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Requires that the two types unify, and prints an error message if
     /// they don't.
     pub fn demand_suptype(&self, sp: Span, expected: Ty<'tcx>, actual: Ty<'tcx>) {
-        if let Some(e) = self.demand_suptype_diag(sp, expected, actual) {
+        if let Err(e) = self.demand_suptype_diag(sp, expected, actual) {
             e.emit();
         }
     }
@@ -176,7 +176,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         sp: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Result<(), Diag<'tcx>> {
         self.demand_suptype_with_origin(&self.misc(sp), expected, actual)
     }
 
@@ -186,18 +186,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<Diag<'tcx>> {
-        match self.at(cause, self.param_env).sup(DefineOpaqueTypes::Yes, expected, actual) {
-            Ok(InferOk { obligations, value: () }) => {
-                self.register_predicates(obligations);
-                None
-            }
-            Err(e) => Some(self.err_ctxt().report_mismatched_types(cause, expected, actual, e)),
-        }
+    ) -> Result<(), Diag<'tcx>> {
+        self.at(cause, self.param_env)
+            .sup(DefineOpaqueTypes::Yes, expected, actual)
+            .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
+            .map_err(|e| self.err_ctxt().report_mismatched_types(cause, expected, actual, e))
     }
 
     pub fn demand_eqtype(&self, sp: Span, expected: Ty<'tcx>, actual: Ty<'tcx>) {
-        if let Some(err) = self.demand_eqtype_diag(sp, expected, actual) {
+        if let Err(err) = self.demand_eqtype_diag(sp, expected, actual) {
             err.emit();
         }
     }
@@ -207,7 +204,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         sp: Span,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Result<(), Diag<'tcx>> {
         self.demand_eqtype_with_origin(&self.misc(sp), expected, actual)
     }
 
@@ -216,14 +213,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
-    ) -> Option<Diag<'tcx>> {
-        match self.at(cause, self.param_env).eq(DefineOpaqueTypes::Yes, expected, actual) {
-            Ok(InferOk { obligations, value: () }) => {
-                self.register_predicates(obligations);
-                None
-            }
-            Err(e) => Some(self.err_ctxt().report_mismatched_types(cause, expected, actual, e)),
-        }
+    ) -> Result<(), Diag<'tcx>> {
+        self.at(cause, self.param_env)
+            .eq(DefineOpaqueTypes::Yes, expected, actual)
+            .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
+            .map_err(|e| self.err_ctxt().report_mismatched_types(cause, expected, actual, e))
     }
 
     pub fn demand_coerce(
@@ -234,12 +228,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
         allow_two_phase: AllowTwoPhase,
     ) -> Ty<'tcx> {
-        let (ty, err) =
-            self.demand_coerce_diag(expr, checked_ty, expected, expected_ty_expr, allow_two_phase);
-        if let Some(err) = err {
-            err.emit();
+        match self.demand_coerce_diag(expr, checked_ty, expected, expected_ty_expr, allow_two_phase)
+        {
+            Ok(ty) => ty,
+            Err(err) => {
+                err.emit();
+                // Return the original type instead of an error type here, otherwise the type of `x` in
+                // `let x: u32 = ();` will be a type error, causing all subsequent usages of `x` to not
+                // report errors, even though `x` is definitely `u32`.
+                expected
+            }
         }
-        ty
     }
 
     /// Checks that the type of `expr` can be coerced to `expected`.
@@ -254,11 +253,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         mut expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
         allow_two_phase: AllowTwoPhase,
-    ) -> (Ty<'tcx>, Option<Diag<'tcx>>) {
+    ) -> Result<Ty<'tcx>, Diag<'tcx>> {
         let expected = self.resolve_vars_with_obligations(expected);
 
         let e = match self.coerce(expr, checked_ty, expected, allow_two_phase, None) {
-            Ok(ty) => return (ty, None),
+            Ok(ty) => return Ok(ty),
             Err(e) => e,
         };
 
@@ -275,7 +274,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         self.emit_coerce_suggestions(&mut err, expr, expr_ty, expected, expected_ty_expr, Some(e));
 
-        (expected, Some(err))
+        Err(err)
     }
 
     /// Notes the point at which a variable is constrained to some type incompatible
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 7fd081593854d..c4e55d564a019 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -87,7 +87,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ty = adj_ty;
         }
 
-        if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) {
+        if let Err(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) {
             let _ = self.emit_type_mismatch_suggestions(
                 &mut err,
                 expr.peel_drop_temps(),
@@ -1132,7 +1132,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // say that the user intended to write `lhs == rhs` instead of `lhs = rhs`.
             // The likely cause of this is `if foo = bar { .. }`.
             let actual_ty = self.tcx.types.unit;
-            let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap();
+            let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap_err();
             let lhs_ty = self.check_expr(lhs);
             let rhs_ty = self.check_expr(rhs);
             let refs_can_coerce = |lhs: Ty<'tcx>, rhs: Ty<'tcx>| {
@@ -1236,7 +1236,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // This is (basically) inlined `check_expr_coercible_to_type`, but we want
         // to suggest an additional fixup here in `suggest_deref_binop`.
         let rhs_ty = self.check_expr_with_hint(rhs, lhs_ty);
-        if let (_, Some(mut diag)) =
+        if let Err(mut diag) =
             self.demand_coerce_diag(rhs, rhs_ty, lhs_ty, Some(lhs), AllowTwoPhase::No)
         {
             suggest_deref_binop(&mut diag, rhs_ty);
@@ -1738,10 +1738,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Make sure to give a type to the field even if there's
             // an error, so we can continue type-checking.
             let ty = self.check_expr_with_hint(field.expr, field_type);
-            let (_, diag) =
-                self.demand_coerce_diag(field.expr, ty, field_type, None, AllowTwoPhase::No);
+            let diag = self.demand_coerce_diag(field.expr, ty, field_type, None, AllowTwoPhase::No);
 
-            if let Some(diag) = diag {
+            if let Err(diag) = diag {
                 if idx == hir_fields.len() - 1 {
                     if remaining_fields.is_empty() {
                         self.suggest_fru_from_range_and_emit(field, variant, args, diag);
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index 94e879ae9c3ed..9531c002829ea 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -1418,7 +1418,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let impl_ty = self.normalize(span, tcx.type_of(impl_def_id).instantiate(tcx, args));
             let self_ty = self.normalize(span, self_ty);
             match self.at(&self.misc(span), self.param_env).eq(
-                DefineOpaqueTypes::No,
+                DefineOpaqueTypes::Yes,
                 impl_ty,
                 self_ty,
             ) {
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 172d874d4eed7..10d9e07db6f1f 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -1578,7 +1578,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // type of the place it is referencing, and not some
             // supertype thereof.
             let init_ty = self.check_expr_with_needs(init, Needs::maybe_mut_place(m));
-            if let Some(mut diag) = self.demand_eqtype_diag(init.span, local_ty, init_ty) {
+            if let Err(mut diag) = self.demand_eqtype_diag(init.span, local_ty, init_ty) {
                 self.emit_type_mismatch_suggestions(
                     &mut diag,
                     init.peel_drop_temps(),
@@ -1624,7 +1624,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let previous_diverges = self.diverges.get();
             let else_ty = self.check_block_with_expected(blk, NoExpectation);
             let cause = self.cause(blk.span, ObligationCauseCode::LetElse);
-            if let Some(err) = self.demand_eqtype_with_origin(&cause, self.tcx.types.never, else_ty)
+            if let Err(err) = self.demand_eqtype_with_origin(&cause, self.tcx.types.never, else_ty)
             {
                 err.emit();
             }
diff --git a/compiler/rustc_hir_typeck/src/method/confirm.rs b/compiler/rustc_hir_typeck/src/method/confirm.rs
index 3c9a49e91a3f9..120e3239d1f1b 100644
--- a/compiler/rustc_hir_typeck/src/method/confirm.rs
+++ b/compiler/rustc_hir_typeck/src/method/confirm.rs
@@ -497,7 +497,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                 args,
             })),
         );
-        match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::No, method_self_ty, self_ty) {
+        match self.at(&cause, self.param_env).sup(DefineOpaqueTypes::Yes, method_self_ty, self_ty) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
             }
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index e842bba34bf82..3986374a343f0 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -634,8 +634,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_probe(&mut self, self_ty: &Canonical<'tcx, QueryResponse<'tcx, Ty<'tcx>>>) {
-        debug!("assemble_probe: self_ty={:?}", self_ty);
         let raw_self_ty = self_ty.value.value;
         match *raw_self_ty.kind() {
             ty::Dynamic(data, ..) if let Some(p) = data.principal() => {
@@ -713,13 +713,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_inherent_impl_probe(&mut self, impl_def_id: DefId) {
         if !self.impl_dups.insert(impl_def_id) {
             return; // already visited
         }
 
-        debug!("assemble_inherent_impl_probe {:?}", impl_def_id);
-
         for item in self.impl_or_trait_item(impl_def_id) {
             if !self.has_applicable_self(&item) {
                 // No receiver declared. Not a candidate.
@@ -737,9 +736,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_inherent_candidates_from_object(&mut self, self_ty: Ty<'tcx>) {
-        debug!("assemble_inherent_candidates_from_object(self_ty={:?})", self_ty);
-
         let principal = match self_ty.kind() {
             ty::Dynamic(ref data, ..) => Some(data),
             _ => None,
@@ -768,9 +766,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         });
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_inherent_candidates_from_param(&mut self, param_ty: ty::ParamTy) {
         // FIXME: do we want to commit to this behavior for param bounds?
-        debug!("assemble_inherent_candidates_from_param(param_ty={:?})", param_ty);
 
         let bounds = self.param_env.caller_bounds().iter().filter_map(|predicate| {
             let bound_predicate = predicate.kind();
@@ -826,6 +824,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_extension_candidates_for_traits_in_scope(&mut self) {
         let mut duplicates = FxHashSet::default();
         let opt_applicable_traits = self.tcx.in_scope_traits(self.scope_expr_id);
@@ -842,6 +841,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_extension_candidates_for_all_traits(&mut self) {
         let mut duplicates = FxHashSet::default();
         for trait_info in suggest::all_traits(self.tcx) {
@@ -863,12 +863,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn assemble_extension_candidates_for_trait(
         &mut self,
         import_ids: &SmallVec<[LocalDefId; 1]>,
         trait_def_id: DefId,
     ) {
-        debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id);
         let trait_args = self.fresh_args_for_item(self.span, trait_def_id);
         let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, trait_args);
 
@@ -958,6 +958,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
     ///////////////////////////////////////////////////////////////////////////
     // THE ACTUAL SEARCH
 
+    #[instrument(level = "debug", skip(self))]
     fn pick(mut self) -> PickResult<'tcx> {
         assert!(self.method_name.is_some());
 
@@ -1386,6 +1387,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "trace", skip(self, possibly_unsatisfied_predicates), ret)]
     fn consider_probe(
         &self,
         self_ty: Ty<'tcx>,
@@ -1415,15 +1417,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     (xform_self_ty, xform_ret_ty) =
                         self.xform_self_ty(probe.item, impl_ty, impl_args);
                     xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
-                    // FIXME: Make this `ocx.sup` once we define opaques more eagerly.
-                    match self.at(cause, self.param_env).sup(
-                        DefineOpaqueTypes::No,
-                        xform_self_ty,
-                        self_ty,
-                    ) {
-                        Ok(infer_ok) => {
-                            ocx.register_infer_ok_obligations(infer_ok);
-                        }
+                    match ocx.sup(cause, self.param_env, xform_self_ty, self_ty) {
+                        Ok(()) => {}
                         Err(err) => {
                             debug!("--> cannot relate self-types {:?}", err);
                             return ProbeResult::NoMatch;
@@ -1484,19 +1479,23 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     (xform_self_ty, xform_ret_ty) =
                         self.xform_self_ty(probe.item, trait_ref.self_ty(), trait_ref.args);
                     xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
-                    // FIXME: Make this `ocx.sup` once we define opaques more eagerly.
-                    match self.at(cause, self.param_env).sup(
-                        DefineOpaqueTypes::No,
-                        xform_self_ty,
-                        self_ty,
-                    ) {
-                        Ok(infer_ok) => {
-                            ocx.register_infer_ok_obligations(infer_ok);
-                        }
-                        Err(err) => {
-                            debug!("--> cannot relate self-types {:?}", err);
+                    match self_ty.kind() {
+                        // HACK: opaque types will match anything for which their bounds hold.
+                        // Thus we need to prevent them from trying to match the `&_` autoref
+                        // candidates that get created for `&self` trait methods.
+                        ty::Alias(ty::Opaque, alias_ty)
+                            if self.infcx.can_define_opaque_ty(alias_ty.def_id)
+                                && !xform_self_ty.is_ty_var() =>
+                        {
                             return ProbeResult::NoMatch;
                         }
+                        _ => match ocx.sup(cause, self.param_env, xform_self_ty, self_ty) {
+                            Ok(()) => {}
+                            Err(err) => {
+                                debug!("--> cannot relate self-types {:?}", err);
+                                return ProbeResult::NoMatch;
+                            }
+                        },
                     }
                     let obligation = traits::Obligation::new(
                         self.tcx,
@@ -1536,15 +1535,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     (xform_self_ty, xform_ret_ty) =
                         self.xform_self_ty(probe.item, trait_ref.self_ty(), trait_ref.args);
                     xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
-                    // FIXME: Make this `ocx.sup` once we define opaques more eagerly.
-                    match self.at(cause, self.param_env).sup(
-                        DefineOpaqueTypes::No,
-                        xform_self_ty,
-                        self_ty,
-                    ) {
-                        Ok(infer_ok) => {
-                            ocx.register_infer_ok_obligations(infer_ok);
-                        }
+                    match ocx.sup(cause, self.param_env, xform_self_ty, self_ty) {
+                        Ok(()) => {}
                         Err(err) => {
                             debug!("--> cannot relate self-types {:?}", err);
                             return ProbeResult::NoMatch;
@@ -1665,6 +1657,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
     /// Similarly to `probe_for_return_type`, this method attempts to find the best matching
     /// candidate method where the method name may have been misspelled. Similarly to other
     /// edit distance based suggestions, we provide at most one such suggestion.
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn probe_for_similar_candidate(
         &mut self,
     ) -> Result<Option<ty::AssocItem>, MethodError<'tcx>> {
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 9476dc704831d..220556fe2568b 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -105,15 +105,16 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
         ti: &TopInfo<'tcx>,
-    ) -> Option<Diag<'tcx>> {
-        let mut diag =
-            self.demand_eqtype_with_origin(&self.pattern_cause(ti, cause_span), expected, actual)?;
-        if let Some(expr) = ti.origin_expr {
-            self.suggest_fn_call(&mut diag, expr, expected, |output| {
-                self.can_eq(self.param_env, output, actual)
-            });
-        }
-        Some(diag)
+    ) -> Result<(), Diag<'tcx>> {
+        self.demand_eqtype_with_origin(&self.pattern_cause(ti, cause_span), expected, actual)
+            .map_err(|mut diag| {
+                if let Some(expr) = ti.origin_expr {
+                    self.suggest_fn_call(&mut diag, expr, expected, |output| {
+                        self.can_eq(self.param_env, output, actual)
+                    });
+                }
+                diag
+            })
     }
 
     fn demand_eqtype_pat(
@@ -122,10 +123,8 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
         ti: &TopInfo<'tcx>,
-    ) {
-        if let Some(err) = self.demand_eqtype_pat_diag(cause_span, expected, actual, ti) {
-            err.emit();
-        }
+    ) -> Result<(), ErrorGuaranteed> {
+        self.demand_eqtype_pat_diag(cause_span, expected, actual, ti).map_err(|err| err.emit())
     }
 }
 
@@ -509,7 +508,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         //
         // then that's equivalent to there existing a LUB.
         let cause = self.pattern_cause(ti, span);
-        if let Some(err) = self.demand_suptype_with_origin(&cause, expected, pat_ty) {
+        if let Err(err) = self.demand_suptype_with_origin(&cause, expected, pat_ty) {
             err.emit_unless(
                 ti.span
                     .filter(|&s| {
@@ -562,7 +561,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Subtyping doesn't matter here, as the value is some kind of scalar.
         let demand_eqtype = |x: &mut _, y| {
             if let Some((ref mut fail, x_ty, x_span)) = *x
-                && let Some(mut err) = self.demand_eqtype_pat_diag(x_span, expected, x_ty, ti)
+                && let Err(mut err) = self.demand_eqtype_pat_diag(x_span, expected, x_ty, ti)
             {
                 if let Some((_, y_ty, y_span)) = y {
                     self.endpoint_has_type(&mut err, y_span, y_ty);
@@ -736,7 +735,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Otherwise, the type of x is the expected type `T`.
             ByRef::No => expected, // As above, `T <: typeof(x)` is required, but we use equality, see (note_1).
         };
-        self.demand_eqtype_pat(pat.span, eq_ty, local_ty, ti);
+
+        // We have a concrete type for the local, so we do not need to taint it and hide follow up errors *using* the local.
+        let _ = self.demand_eqtype_pat(pat.span, eq_ty, local_ty, ti);
 
         // If there are multiple arms, make sure they all agree on
         // what the type of the binding `x` ought to be.
@@ -763,7 +764,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         ti: &TopInfo<'tcx>,
     ) {
         let var_ty = self.local_ty(span, var_id);
-        if let Some(mut err) = self.demand_eqtype_pat_diag(span, var_ty, ty, ti) {
+        if let Err(mut err) = self.demand_eqtype_pat_diag(span, var_ty, ty, ti) {
             let hir = self.tcx.hir();
             let var_ty = self.resolve_vars_if_possible(var_ty);
             let msg = format!("first introduced with type `{var_ty}` here");
@@ -986,13 +987,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         // Type-check the path.
-        self.demand_eqtype_pat(pat.span, expected, pat_ty, pat_info.top_info);
+        let _ = self.demand_eqtype_pat(pat.span, expected, pat_ty, pat_info.top_info);
 
         // Type-check subpatterns.
-        if self.check_struct_pat_fields(pat_ty, pat, variant, fields, has_rest_pat, pat_info) {
-            pat_ty
-        } else {
-            Ty::new_misc_error(self.tcx)
+        match self.check_struct_pat_fields(pat_ty, pat, variant, fields, has_rest_pat, pat_info) {
+            Ok(()) => pat_ty,
+            Err(guar) => Ty::new_error(self.tcx, guar),
         }
     }
 
@@ -1050,7 +1050,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Type-check the path.
         let (pat_ty, pat_res) =
             self.instantiate_value_path(segments, opt_ty, res, pat.span, pat.span, pat.hir_id);
-        if let Some(err) =
+        if let Err(err) =
             self.demand_suptype_with_origin(&self.pattern_cause(ti, pat.span), expected, pat_ty)
         {
             self.emit_bad_pat_path(err, pat, res, pat_res, pat_ty, segments);
@@ -1223,12 +1223,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Type-check the tuple struct pattern against the expected type.
         let diag = self.demand_eqtype_pat_diag(pat.span, expected, pat_ty, pat_info.top_info);
-        let had_err = if let Some(err) = diag {
-            err.emit();
-            true
-        } else {
-            false
-        };
+        let had_err = diag.map_err(|diag| diag.emit());
 
         // Type-check subpatterns.
         if subpats.len() == variant.fields.len()
@@ -1249,6 +1244,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     None,
                 );
             }
+            if let Err(e) = had_err {
+                on_error(e);
+                return Ty::new_error(tcx, e);
+            }
         } else {
             let e = self.emit_err_pat_wrong_number_of_fields(
                 pat.span,
@@ -1273,7 +1272,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         subpats: &'tcx [Pat<'tcx>],
         fields: &'tcx [ty::FieldDef],
         expected: Ty<'tcx>,
-        had_err: bool,
+        had_err: Result<(), ErrorGuaranteed>,
     ) -> ErrorGuaranteed {
         let subpats_ending = pluralize!(subpats.len());
         let fields_ending = pluralize!(fields.len());
@@ -1330,7 +1329,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // #67037: only do this if we could successfully type-check the expected type against
             // the tuple struct pattern. Otherwise the args could get out of range on e.g.,
             // `let P() = U;` where `P != U` with `struct P<T>(T);`.
-            (ty::Adt(_, args), [field], false) => {
+            (ty::Adt(_, args), [field], Ok(())) => {
                 let field_ty = self.field_ty(pat_span, field, args);
                 match field_ty.kind() {
                     ty::Tuple(fields) => fields.len() == subpats.len(),
@@ -1445,8 +1444,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let element_tys_iter = (0..max_len).map(|_| self.next_ty_var(span));
         let element_tys = tcx.mk_type_list_from_iter(element_tys_iter);
         let pat_ty = Ty::new_tup(tcx, element_tys);
-        if let Some(err) = self.demand_eqtype_pat_diag(span, expected, pat_ty, pat_info.top_info) {
-            let reported = err.emit();
+        if let Err(reported) = self.demand_eqtype_pat(span, expected, pat_ty, pat_info.top_info) {
             // Walk subpatterns with an expected type of `err` in this case to silence
             // further errors being emitted when using the bindings. #50333
             let element_tys_iter = (0..max_len).map(|_| Ty::new_error(tcx, reported));
@@ -1470,7 +1468,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         fields: &'tcx [hir::PatField<'tcx>],
         has_rest_pat: bool,
         pat_info: PatInfo<'tcx, '_>,
-    ) -> bool {
+    ) -> Result<(), ErrorGuaranteed> {
         let tcx = self.tcx;
 
         let ty::Adt(adt, args) = adt_ty.kind() else {
@@ -1486,7 +1484,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Keep track of which fields have already appeared in the pattern.
         let mut used_fields = FxHashMap::default();
-        let mut no_field_errors = true;
+        let mut result = Ok(());
 
         let mut inexistent_fields = vec![];
         // Typecheck each field.
@@ -1495,8 +1493,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let ident = tcx.adjust_ident(field.ident, variant.def_id);
             let field_ty = match used_fields.entry(ident) {
                 Occupied(occupied) => {
-                    no_field_errors = false;
                     let guar = self.error_field_already_bound(span, field.ident, *occupied.get());
+                    result = Err(guar);
                     Ty::new_error(tcx, guar)
                 }
                 Vacant(vacant) => {
@@ -1511,7 +1509,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         })
                         .unwrap_or_else(|| {
                             inexistent_fields.push(field);
-                            no_field_errors = false;
                             Ty::new_misc_error(tcx)
                         })
                 }
@@ -1585,37 +1582,31 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
         match (inexistent_fields_err, unmentioned_err) {
             (Some(i), Some(u)) => {
-                if let Some(e) = self.error_tuple_variant_as_struct_pat(pat, fields, variant) {
+                if let Err(e) = self.error_tuple_variant_as_struct_pat(pat, fields, variant) {
                     // We don't want to show the nonexistent fields error when this was
                     // `Foo { a, b }` when it should have been `Foo(a, b)`.
                     i.delay_as_bug();
                     u.delay_as_bug();
-                    e.emit();
+                    Err(e)
                 } else {
                     i.emit();
-                    u.emit();
+                    Err(u.emit())
                 }
             }
             (None, Some(u)) => {
-                if let Some(e) = self.error_tuple_variant_as_struct_pat(pat, fields, variant) {
+                if let Err(e) = self.error_tuple_variant_as_struct_pat(pat, fields, variant) {
                     u.delay_as_bug();
-                    e.emit();
+                    Err(e)
                 } else {
-                    u.emit();
+                    Err(u.emit())
                 }
             }
-            (Some(err), None) => {
-                err.emit();
-            }
-            (None, None)
-                if let Some(err) =
-                    self.error_tuple_variant_index_shorthand(variant, pat, fields) =>
-            {
-                err.emit();
+            (Some(err), None) => Err(err.emit()),
+            (None, None) => {
+                self.error_tuple_variant_index_shorthand(variant, pat, fields)?;
+                result
             }
-            (None, None) => {}
         }
-        no_field_errors
     }
 
     fn error_tuple_variant_index_shorthand(
@@ -1623,7 +1614,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         variant: &VariantDef,
         pat: &'_ Pat<'_>,
         fields: &[hir::PatField<'_>],
-    ) -> Option<Diag<'_>> {
+    ) -> Result<(), ErrorGuaranteed> {
         // if this is a tuple struct, then all field names will be numbers
         // so if any fields in a struct pattern use shorthand syntax, they will
         // be invalid identifiers (for example, Foo { 0, 1 }).
@@ -1645,10 +1636,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     format!("({})", self.get_suggested_tuple_struct_pattern(fields, variant)),
                     Applicability::MaybeIncorrect,
                 );
-                return Some(err);
+                return Err(err.emit());
             }
         }
-        None
+        Ok(())
     }
 
     fn error_foreign_non_exhaustive_spat(&self, pat: &Pat<'_>, descr: &str, no_fields: bool) {
@@ -1804,14 +1795,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         pat: &Pat<'_>,
         fields: &'tcx [hir::PatField<'tcx>],
         variant: &ty::VariantDef,
-    ) -> Option<Diag<'tcx>> {
+    ) -> Result<(), ErrorGuaranteed> {
         if let (Some(CtorKind::Fn), PatKind::Struct(qpath, pattern_fields, ..)) =
             (variant.ctor_kind(), &pat.kind)
         {
             let is_tuple_struct_match = !pattern_fields.is_empty()
                 && pattern_fields.iter().map(|field| field.ident.name.as_str()).all(is_number);
             if is_tuple_struct_match {
-                return None;
+                return Ok(());
             }
 
             let path = rustc_hir_pretty::qpath_to_string(&self.tcx, qpath);
@@ -1839,9 +1830,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 format!("({sugg})"),
                 appl,
             );
-            return Some(err);
+            return Err(err.emit());
         }
-        None
+        Ok(())
     }
 
     fn get_suggested_tuple_struct_pattern(
@@ -2065,20 +2056,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         pat_info: PatInfo<'tcx, '_>,
     ) -> Ty<'tcx> {
         let tcx = self.tcx;
-        let (box_ty, inner_ty) = match self.check_dereferenceable(span, expected, inner) {
-            Ok(()) => {
+        let (box_ty, inner_ty) = self
+            .check_dereferenceable(span, expected, inner)
+            .and_then(|()| {
                 // Here, `demand::subtype` is good enough, but I don't
                 // think any errors can be introduced by using `demand::eqtype`.
                 let inner_ty = self.next_ty_var(inner.span);
                 let box_ty = Ty::new_box(tcx, inner_ty);
-                self.demand_eqtype_pat(span, expected, box_ty, pat_info.top_info);
-                (box_ty, inner_ty)
-            }
-            Err(guar) => {
+                self.demand_eqtype_pat(span, expected, box_ty, pat_info.top_info)?;
+                Ok((box_ty, inner_ty))
+            })
+            .unwrap_or_else(|guar| {
                 let err = Ty::new_error(tcx, guar);
                 (err, err)
-            }
-        };
+            });
         self.check_pat(inner, inner_ty, pat_info);
         box_ty
     }
@@ -2222,7 +2213,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                         // Look for a case like `fn foo(&foo: u32)` and suggest
                         // `fn foo(foo: &u32)`
-                        if let Some(mut err) = err {
+                        if let Err(mut err) = err {
                             self.borrow_pat_suggestion(&mut err, pat);
                             err.emit();
                         }
@@ -2327,7 +2318,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.try_resolve_slice_ty_to_array_ty(before, slice, span)
             {
                 debug!(?resolved_arr_ty);
-                self.demand_eqtype(span, expected, resolved_arr_ty);
+                let _ = self.demand_eqtype(span, expected, resolved_arr_ty);
             }
         }
 
diff --git a/compiler/rustc_middle/src/traits/query.rs b/compiler/rustc_middle/src/traits/query.rs
index 50b6c77e1b29d..4fad721ce9847 100644
--- a/compiler/rustc_middle/src/traits/query.rs
+++ b/compiler/rustc_middle/src/traits/query.rs
@@ -156,7 +156,7 @@ pub struct CandidateStep<'tcx> {
 
 #[derive(Copy, Clone, Debug, HashStable)]
 pub struct MethodAutoderefStepsResult<'tcx> {
-    /// The valid autoderef steps that could be find.
+    /// The valid autoderef steps that could be found.
     pub steps: &'tcx [CandidateStep<'tcx>],
     /// If Some(T), a type autoderef reported an error on.
     pub opt_bad_ty: Option<&'tcx MethodAutoderefBadTy<'tcx>>,
diff --git a/library/std/src/sys/pal/unix/fs.rs b/library/std/src/sys/pal/unix/fs.rs
index 56a0f8e39c4aa..035c92bc84bfe 100644
--- a/library/std/src/sys/pal/unix/fs.rs
+++ b/library/std/src/sys/pal/unix/fs.rs
@@ -22,16 +22,12 @@ use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
 
 #[cfg(any(all(target_os = "linux", target_env = "gnu"), target_vendor = "apple"))]
 use crate::sys::weak::syscall;
-#[cfg(any(target_os = "android", target_os = "macos", target_os = "solaris"))]
+#[cfg(target_os = "android")]
 use crate::sys::weak::weak;
 
 use libc::{c_int, mode_t};
 
-#[cfg(any(
-    target_os = "solaris",
-    all(target_os = "linux", target_env = "gnu"),
-    target_vendor = "apple",
-))]
+#[cfg(any(all(target_os = "linux", target_env = "gnu"), target_vendor = "apple"))]
 use libc::c_char;
 #[cfg(any(
     all(target_os = "linux", not(target_env = "musl")),
@@ -1753,19 +1749,6 @@ pub fn link(original: &Path, link: &Path) -> io::Result<()> {
                     // Android has `linkat` on newer versions, but we happen to know `link`
                     // always has the correct behavior, so it's here as well.
                     cvt(unsafe { libc::link(original.as_ptr(), link.as_ptr()) })?;
-                } else if #[cfg(any(target_os = "macos", target_os = "solaris"))] {
-                    // MacOS (<=10.9) and Solaris 10 lack support for linkat while newer
-                    // versions have it. We want to use linkat if it is available, so we use weak!
-                    // to check. `linkat` is preferable to `link` because it gives us a flag to
-                    // specify how symlinks should be handled. We pass 0 as the flags argument,
-                    // meaning it shouldn't follow symlinks.
-                    weak!(fn linkat(c_int, *const c_char, c_int, *const c_char, c_int) -> c_int);
-
-                    if let Some(f) = linkat.get() {
-                        cvt(unsafe { f(libc::AT_FDCWD, original.as_ptr(), libc::AT_FDCWD, link.as_ptr(), 0) })?;
-                    } else {
-                        cvt(unsafe { libc::link(original.as_ptr(), link.as_ptr()) })?;
-                    };
                 } else {
                     // Where we can, use `linkat` instead of `link`; see the comment above
                     // this one for details on why.
diff --git a/src/bootstrap/src/core/build_steps/format.rs b/src/bootstrap/src/core/build_steps/format.rs
index 2deb9168df2ab..b96e26dbb3aea 100644
--- a/src/bootstrap/src/core/build_steps/format.rs
+++ b/src/bootstrap/src/core/build_steps/format.rs
@@ -93,7 +93,7 @@ fn get_modified_rs_files(build: &Builder<'_>) -> Result<Option<Vec<String>>, Str
         return Ok(None);
     }
 
-    get_git_modified_files(&build.config.git_config(), Some(&build.config.src), &vec!["rs"])
+    get_git_modified_files(&build.config.git_config(), Some(&build.config.src), &["rs"])
 }
 
 #[derive(serde_derive::Deserialize)]
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 010e1b8fd51fd..4366a92fbcdf6 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -390,9 +390,7 @@ auto:
   - image: x86_64-mingw
     env:
       SCRIPT: make ci-mingw
-      RUST_CONFIGURE_ARGS: >-
-        --build=x86_64-pc-windows-gnu
-        --enable-profiler
+      RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu
       # We are intentionally allowing an old toolchain on this builder (and that's
       # incompatible with LLVM downloads today).
       NO_DOWNLOAD_CI_LLVM: 1
@@ -440,7 +438,6 @@ auto:
       RUST_CONFIGURE_ARGS: >-
         --build=i686-pc-windows-gnu
         --enable-full-tools
-        --enable-profiler
       # We are intentionally allowing an old toolchain on this builder (and that's
       # incompatible with LLVM downloads today).
       NO_DOWNLOAD_CI_LLVM: 1
@@ -454,7 +451,6 @@ auto:
       RUST_CONFIGURE_ARGS: >-
         --build=x86_64-pc-windows-gnu
         --enable-full-tools
-        --enable-profiler
       # We are intentionally allowing an old toolchain on this builder (and that's
       # incompatible with LLVM downloads today).
       NO_DOWNLOAD_CI_LLVM: 1
diff --git a/src/tools/build-manifest/src/main.rs b/src/tools/build-manifest/src/main.rs
index 9f33e4312740f..b4d47cba7c5bc 100644
--- a/src/tools/build-manifest/src/main.rs
+++ b/src/tools/build-manifest/src/main.rs
@@ -495,7 +495,7 @@ impl Builder {
                 Some(p) => p,
                 None => return false,
             };
-            pkg.target.get(&c.target).is_some()
+            pkg.target.contains_key(&c.target)
         };
         extensions.retain(&has_component);
         components.retain(&has_component);
diff --git a/src/tools/build_helper/src/git.rs b/src/tools/build_helper/src/git.rs
index a3c857b0268c9..b4522de6897d4 100644
--- a/src/tools/build_helper/src/git.rs
+++ b/src/tools/build_helper/src/git.rs
@@ -21,7 +21,7 @@ fn output_result(cmd: &mut Command) -> Result<String, String> {
             String::from_utf8(output.stderr).map_err(|err| format!("{err:?}"))?
         ));
     }
-    Ok(String::from_utf8(output.stdout).map_err(|err| format!("{err:?}"))?)
+    String::from_utf8(output.stdout).map_err(|err| format!("{err:?}"))
 }
 
 /// Finds the remote for rust-lang/rust.
@@ -64,18 +64,14 @@ pub fn rev_exists(rev: &str, git_dir: Option<&Path>) -> Result<bool, String> {
     match output.status.code() {
         Some(0) => Ok(true),
         Some(128) => Ok(false),
-        None => {
-            return Err(format!(
-                "git didn't exit properly: {}",
-                String::from_utf8(output.stderr).map_err(|err| format!("{err:?}"))?
-            ));
-        }
-        Some(code) => {
-            return Err(format!(
-                "git command exited with status code: {code}: {}",
-                String::from_utf8(output.stderr).map_err(|err| format!("{err:?}"))?
-            ));
-        }
+        None => Err(format!(
+            "git didn't exit properly: {}",
+            String::from_utf8(output.stderr).map_err(|err| format!("{err:?}"))?
+        )),
+        Some(code) => Err(format!(
+            "git command exited with status code: {code}: {}",
+            String::from_utf8(output.stderr).map_err(|err| format!("{err:?}"))?
+        )),
     }
 }
 
@@ -96,7 +92,7 @@ pub fn updated_master_branch(
         }
     }
 
-    Err(format!("Cannot find any suitable upstream master branch"))
+    Err("Cannot find any suitable upstream master branch".to_owned())
 }
 
 pub fn get_git_merge_base(
@@ -118,7 +114,7 @@ pub fn get_git_merge_base(
 pub fn get_git_modified_files(
     config: &GitConfig<'_>,
     git_dir: Option<&Path>,
-    extensions: &Vec<&str>,
+    extensions: &[&str],
 ) -> Result<Option<Vec<String>>, String> {
     let merge_base = get_git_merge_base(config, git_dir)?;
 
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index b0047770564c4..da7f03441e72f 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -582,7 +582,7 @@ impl TargetCfgs {
                         name,
                         Some(
                             value
-                                .strip_suffix("\"")
+                                .strip_suffix('\"')
                                 .expect("key-value pair should be properly quoted"),
                         ),
                     )
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index da0196dad2ff7..8f2b0a7e91a41 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -81,7 +81,7 @@ impl EarlyProps {
             panic!("errors encountered during EarlyProps parsing");
         }
 
-        return props;
+        props
     }
 }
 
@@ -381,7 +381,7 @@ impl TestProps {
                         // Individual flags can be single-quoted to preserve spaces; see
                         // <https://github.com/rust-lang/rust/pull/115948/commits/957c5db6>.
                         flags
-                            .split("'")
+                            .split('\'')
                             .enumerate()
                             .flat_map(|(i, f)| {
                                 if i % 2 == 1 { vec![f] } else { f.split_whitespace().collect() }
@@ -612,7 +612,7 @@ impl TestProps {
 
         for key in &["RUST_TEST_NOCAPTURE", "RUST_TEST_THREADS"] {
             if let Ok(val) = env::var(key) {
-                if self.exec_env.iter().find(|&&(ref x, _)| x == key).is_none() {
+                if !self.exec_env.iter().any(|&(ref x, _)| x == key) {
                     self.exec_env.push(((*key).to_owned(), val))
                 }
             }
@@ -990,7 +990,7 @@ pub(crate) fn check_directive(directive_ln: &str) -> CheckDirectiveResult<'_> {
     let trailing = post.trim().split_once(' ').map(|(pre, _)| pre).unwrap_or(post);
     let trailing_directive = {
         // 1. is the directive name followed by a space? (to exclude `:`)
-        matches!(directive_ln.get(directive_name.len()..), Some(s) if s.starts_with(" "))
+        matches!(directive_ln.get(directive_name.len()..), Some(s) if s.starts_with(' '))
             // 2. is what is after that directive also a directive (ex: "only-x86 only-arm")
             && KNOWN_DIRECTIVE_NAMES.contains(&trailing)
     }
@@ -1022,9 +1022,6 @@ fn iter_header(
     if mode == Mode::CoverageRun {
         let extra_directives: &[&str] = &[
             "needs-profiler-support",
-            // FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-            // properly. Since we only have GCC on the CI ignore the test for now.
-            "ignore-windows-gnu",
             // FIXME(pietroalbini): this test currently does not work on cross-compiled
             // targets because remote-test is not capable of sending back the *.profraw
             // files generated by the LLVM instrumentation.
@@ -1357,7 +1354,7 @@ pub fn extract_llvm_version_from_binary(binary_path: &str) -> Option<u32> {
     }
     let version = String::from_utf8(output.stdout).ok()?;
     for line in version.lines() {
-        if let Some(version) = line.split("LLVM version ").skip(1).next() {
+        if let Some(version) = line.split("LLVM version ").nth(1) {
             return extract_llvm_version(version);
         }
     }
@@ -1388,7 +1385,7 @@ where
 
     let min = parse(min)?;
     let max = match max {
-        Some(max) if max.is_empty() => return None,
+        Some("") => return None,
         Some(max) => parse(max)?,
         _ => min,
     };
@@ -1460,12 +1457,12 @@ pub fn make_test_description<R: Read>(
             decision!(ignore_gdb(config, ln));
             decision!(ignore_lldb(config, ln));
 
-            if config.target == "wasm32-unknown-unknown" {
-                if config.parse_name_directive(ln, directives::CHECK_RUN_RESULTS) {
-                    decision!(IgnoreDecision::Ignore {
-                        reason: "ignored on WASM as the run results cannot be checked there".into(),
-                    });
-                }
+            if config.target == "wasm32-unknown-unknown"
+                && config.parse_name_directive(ln, directives::CHECK_RUN_RESULTS)
+            {
+                decision!(IgnoreDecision::Ignore {
+                    reason: "ignored on WASM as the run results cannot be checked there".into(),
+                });
             }
 
             should_fail |= config.parse_name_directive(ln, "should-fail");
diff --git a/src/tools/compiletest/src/header/cfg.rs b/src/tools/compiletest/src/header/cfg.rs
index 510043e3bfd8f..522c52b1de2a7 100644
--- a/src/tools/compiletest/src/header/cfg.rs
+++ b/src/tools/compiletest/src/header/cfg.rs
@@ -58,7 +58,7 @@ pub(super) fn parse_cfg_name_directive<'a>(
 
     // Some of the matchers might be "" depending on what the target information is. To avoid
     // problems we outright reject empty directives.
-    if name == "" {
+    if name.is_empty() {
         return ParsedNameDirective::not_a_directive();
     }
 
diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs
index 62e71e9b59ddb..0cf05b32e9681 100644
--- a/src/tools/compiletest/src/lib.rs
+++ b/src/tools/compiletest/src/lib.rs
@@ -1147,7 +1147,7 @@ fn extract_lldb_version(full_version_line: &str) -> Option<(u32, bool)> {
 }
 
 fn not_a_digit(c: char) -> bool {
-    !c.is_digit(10)
+    !c.is_ascii_digit()
 }
 
 fn check_overlapping_tests(found_paths: &HashSet<PathBuf>) {
diff --git a/src/tools/compiletest/src/read2.rs b/src/tools/compiletest/src/read2.rs
index 3f1921cb6bd5a..8c06339f3c36d 100644
--- a/src/tools/compiletest/src/read2.rs
+++ b/src/tools/compiletest/src/read2.rs
@@ -6,7 +6,6 @@ mod tests;
 
 pub use self::imp::read2;
 use std::io::{self, Write};
-use std::mem::replace;
 use std::process::{Child, Output};
 
 #[derive(Copy, Clone, Debug)]
@@ -101,10 +100,10 @@ impl ProcOutput {
                     return;
                 }
 
-                let mut head = replace(bytes, Vec::new());
+                let mut head = std::mem::take(bytes);
                 // Don't truncate if this as a whole line.
                 // That should make it less likely that we cut a JSON line in half.
-                if head.last() != Some(&('\n' as u8)) {
+                if head.last() != Some(&b'\n') {
                     head.truncate(MAX_OUT_LEN);
                 }
                 let skipped = new_len - head.len();
diff --git a/src/tools/compiletest/src/read2/tests.rs b/src/tools/compiletest/src/read2/tests.rs
index 5ad2db3cb830b..9e052ff069b99 100644
--- a/src/tools/compiletest/src/read2/tests.rs
+++ b/src/tools/compiletest/src/read2/tests.rs
@@ -64,9 +64,9 @@ fn test_abbreviate_filterss_are_detected() {
 #[test]
 fn test_abbreviate_filters_avoid_abbreviations() {
     let mut out = ProcOutput::new();
-    let filters = &[std::iter::repeat('a').take(64).collect::<String>()];
+    let filters = &["a".repeat(64)];
 
-    let mut expected = vec![b'.'; MAX_OUT_LEN - FILTERED_PATHS_PLACEHOLDER_LEN as usize];
+    let mut expected = vec![b'.'; MAX_OUT_LEN - FILTERED_PATHS_PLACEHOLDER_LEN];
     expected.extend_from_slice(filters[0].as_bytes());
 
     out.extend(&expected, filters);
@@ -81,7 +81,7 @@ fn test_abbreviate_filters_avoid_abbreviations() {
 #[test]
 fn test_abbreviate_filters_can_still_cause_abbreviations() {
     let mut out = ProcOutput::new();
-    let filters = &[std::iter::repeat('a').take(64).collect::<String>()];
+    let filters = &["a".repeat(64)];
 
     let mut input = vec![b'.'; MAX_OUT_LEN];
     input.extend_from_slice(filters[0].as_bytes());
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index cc15961b46ed8..147e01cd5b56b 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -382,11 +382,11 @@ impl<'test> TestCx<'test> {
 
         // if a test does not crash, consider it an error
         if proc_res.status.success() || matches!(proc_res.status.code(), Some(1 | 0)) {
-            self.fatal(&format!(
+            self.fatal(
                 "test no longer crashes/triggers ICE! Please give it a mearningful name, \
             add a doc-comment to the start of the test explaining why it exists and \
-            move it to tests/ui or wherever you see fit."
-            ));
+            move it to tests/ui or wherever you see fit.",
+            );
         }
     }
 
@@ -705,10 +705,10 @@ impl<'test> TestCx<'test> {
             // since it is extensively used in the testsuite.
             check_cfg.push_str("cfg(FALSE");
             for revision in &self.props.revisions {
-                check_cfg.push_str(",");
-                check_cfg.push_str(&normalize_revision(&revision));
+                check_cfg.push(',');
+                check_cfg.push_str(&normalize_revision(revision));
             }
-            check_cfg.push_str(")");
+            check_cfg.push(')');
 
             cmd.args(&["--check-cfg", &check_cfg]);
         }
@@ -826,7 +826,7 @@ impl<'test> TestCx<'test> {
         // Append the other `cdb-command:`s
         for line in &dbg_cmds.commands {
             script_str.push_str(line);
-            script_str.push_str("\n");
+            script_str.push('\n');
         }
 
         script_str.push_str("qq\n"); // Quit the debugger (including remote debugger, if any)
@@ -1208,7 +1208,7 @@ impl<'test> TestCx<'test> {
         // Append the other commands
         for line in &dbg_cmds.commands {
             script_str.push_str(line);
-            script_str.push_str("\n");
+            script_str.push('\n');
         }
 
         // Finally, quit the debugger
@@ -1258,7 +1258,7 @@ impl<'test> TestCx<'test> {
         // Remove options that are either unwanted (-O) or may lead to duplicates due to RUSTFLAGS.
         let options_to_remove = ["-O".to_owned(), "-g".to_owned(), "--debuginfo".to_owned()];
 
-        options.iter().filter(|x| !options_to_remove.contains(x)).map(|x| x.clone()).collect()
+        options.iter().filter(|x| !options_to_remove.contains(x)).cloned().collect()
     }
 
     fn maybe_add_external_args(&self, cmd: &mut Command, args: &Vec<String>) {
@@ -2512,8 +2512,8 @@ impl<'test> TestCx<'test> {
             // This works with both `--emit asm` (as default output name for the assembly)
             // and `ptx-linker` because the latter can write output at requested location.
             let output_path = self.output_base_name().with_extension(extension);
-            let output_file = TargetLocation::ThisFile(output_path.clone());
-            output_file
+
+            TargetLocation::ThisFile(output_path.clone())
         }
     }
 
@@ -2760,7 +2760,7 @@ impl<'test> TestCx<'test> {
             for entry in walkdir::WalkDir::new(dir) {
                 let entry = entry.expect("failed to read file");
                 if entry.file_type().is_file()
-                    && entry.path().extension().and_then(|p| p.to_str()) == Some("html".into())
+                    && entry.path().extension().and_then(|p| p.to_str()) == Some("html")
                 {
                     let status =
                         Command::new("tidy").args(&tidy_args).arg(entry.path()).status().unwrap();
@@ -2791,8 +2791,7 @@ impl<'test> TestCx<'test> {
             &compare_dir,
             self.config.verbose,
             |file_type, extension| {
-                file_type.is_file()
-                    && (extension == Some("html".into()) || extension == Some("js".into()))
+                file_type.is_file() && (extension == Some("html") || extension == Some("js"))
             },
         ) {
             return;
@@ -2838,11 +2837,11 @@ impl<'test> TestCx<'test> {
                 }
                 match String::from_utf8(line.clone()) {
                     Ok(line) => {
-                        if line.starts_with("+") {
+                        if line.starts_with('+') {
                             write!(&mut out, "{}", line.green()).unwrap();
-                        } else if line.starts_with("-") {
+                        } else if line.starts_with('-') {
                             write!(&mut out, "{}", line.red()).unwrap();
-                        } else if line.starts_with("@") {
+                        } else if line.starts_with('@') {
                             write!(&mut out, "{}", line.blue()).unwrap();
                         } else {
                             out.write_all(line.as_bytes()).unwrap();
@@ -2915,7 +2914,7 @@ impl<'test> TestCx<'test> {
                     && line.ends_with(';')
                 {
                     if let Some(ref mut other_files) = other_files {
-                        other_files.push(line.rsplit("mod ").next().unwrap().replace(";", ""));
+                        other_files.push(line.rsplit("mod ").next().unwrap().replace(';', ""));
                     }
                     None
                 } else {
@@ -3147,7 +3146,7 @@ impl<'test> TestCx<'test> {
             let mut string = String::new();
             for cgu in cgus {
                 string.push_str(&cgu[..]);
-                string.push_str(" ");
+                string.push(' ');
             }
 
             string
@@ -3180,10 +3179,7 @@ impl<'test> TestCx<'test> {
         // CGUs joined with "--". This function splits such composite CGU names
         // and handles each component individually.
         fn remove_crate_disambiguators_from_set_of_cgu_names(cgus: &str) -> String {
-            cgus.split("--")
-                .map(|cgu| remove_crate_disambiguator_from_cgu(cgu))
-                .collect::<Vec<_>>()
-                .join("--")
+            cgus.split("--").map(remove_crate_disambiguator_from_cgu).collect::<Vec<_>>().join("--")
         }
     }
 
@@ -3365,7 +3361,7 @@ impl<'test> TestCx<'test> {
             //   endif
         }
 
-        if self.config.target.contains("msvc") && self.config.cc != "" {
+        if self.config.target.contains("msvc") && !self.config.cc.is_empty() {
             // We need to pass a path to `lib.exe`, so assume that `cc` is `cl.exe`
             // and that `lib.exe` lives next to it.
             let lib = Path::new(&self.config.cc).parent().unwrap().join("lib.exe");
@@ -3647,7 +3643,7 @@ impl<'test> TestCx<'test> {
             //   endif
         }
 
-        if self.config.target.contains("msvc") && self.config.cc != "" {
+        if self.config.target.contains("msvc") && !self.config.cc.is_empty() {
             // We need to pass a path to `lib.exe`, so assume that `cc` is `cl.exe`
             // and that `lib.exe` lives next to it.
             let lib = Path::new(&self.config.cc).parent().unwrap().join("lib.exe");
@@ -3838,7 +3834,7 @@ impl<'test> TestCx<'test> {
             && !self.props.dont_check_compiler_stderr
         {
             self.fatal_proc_rec(
-                &format!("compiler output got truncated, cannot compare with reference file"),
+                "compiler output got truncated, cannot compare with reference file",
                 &proc_res,
             );
         }
@@ -4019,8 +4015,8 @@ impl<'test> TestCx<'test> {
                     crate_name.to_str().expect("crate name implies file name must be valid UTF-8");
                 // replace `a.foo` -> `a__foo` for crate name purposes.
                 // replace `revision-name-with-dashes` -> `revision_name_with_underscore`
-                let crate_name = crate_name.replace(".", "__");
-                let crate_name = crate_name.replace("-", "_");
+                let crate_name = crate_name.replace('.', "__");
+                let crate_name = crate_name.replace('-', "_");
                 rustc.arg("--crate-name");
                 rustc.arg(crate_name);
             }
@@ -4068,7 +4064,7 @@ impl<'test> TestCx<'test> {
     fn check_mir_dump(&self, test_info: MiroptTest) {
         let test_dir = self.testpaths.file.parent().unwrap();
         let test_crate =
-            self.testpaths.file.file_stem().unwrap().to_str().unwrap().replace("-", "_");
+            self.testpaths.file.file_stem().unwrap().to_str().unwrap().replace('-', "_");
 
         let MiroptTest { run_filecheck, suffix, files, passes: _ } = test_info;
 
diff --git a/src/tools/compiletest/src/runtest/debugger.rs b/src/tools/compiletest/src/runtest/debugger.rs
index eebe5f3580b30..ed6cc97a8abba 100644
--- a/src/tools/compiletest/src/runtest/debugger.rs
+++ b/src/tools/compiletest/src/runtest/debugger.rs
@@ -148,5 +148,5 @@ fn check_single_line(line: &str, check_line: &str) -> bool {
         rest = &rest[pos + current_fragment.len()..];
     }
 
-    if !can_end_anywhere && !rest.is_empty() { false } else { true }
+    can_end_anywhere || rest.is_empty()
 }
diff --git a/src/tools/compiletest/src/tests.rs b/src/tools/compiletest/src/tests.rs
index e6725dba26051..4292f234adc78 100644
--- a/src/tools/compiletest/src/tests.rs
+++ b/src/tools/compiletest/src/tests.rs
@@ -58,11 +58,11 @@ fn test_extract_lldb_version() {
 
 #[test]
 fn is_test_test() {
-    assert_eq!(true, is_test(&OsString::from("a_test.rs")));
-    assert_eq!(false, is_test(&OsString::from(".a_test.rs")));
-    assert_eq!(false, is_test(&OsString::from("a_cat.gif")));
-    assert_eq!(false, is_test(&OsString::from("#a_dog_gif")));
-    assert_eq!(false, is_test(&OsString::from("~a_temp_file")));
+    assert!(is_test(&OsString::from("a_test.rs")));
+    assert!(!is_test(&OsString::from(".a_test.rs")));
+    assert!(!is_test(&OsString::from("a_cat.gif")));
+    assert!(!is_test(&OsString::from("#a_dog_gif")));
+    assert!(!is_test(&OsString::from("~a_temp_file")));
 }
 
 #[test]
diff --git a/src/tools/jsondoclint/src/validator.rs b/src/tools/jsondoclint/src/validator.rs
index 5e35ce242fe4e..1713a4d812c4b 100644
--- a/src/tools/jsondoclint/src/validator.rs
+++ b/src/tools/jsondoclint/src/validator.rs
@@ -418,15 +418,13 @@ impl<'a> Validator<'a> {
             } else {
                 self.fail_expecting(id, expected);
             }
-        } else {
-            if !self.missing_ids.contains(id) {
-                self.missing_ids.insert(id);
+        } else if !self.missing_ids.contains(id) {
+            self.missing_ids.insert(id);
 
-                let sels = json_find::find_selector(&self.krate_json, &Value::String(id.0.clone()));
-                assert_ne!(sels.len(), 0);
+            let sels = json_find::find_selector(&self.krate_json, &Value::String(id.0.clone()));
+            assert_ne!(sels.len(), 0);
 
-                self.fail(id, ErrorKind::NotFound(sels))
-            }
+            self.fail(id, ErrorKind::NotFound(sels))
         }
     }
 
diff --git a/src/tools/lint-docs/src/groups.rs b/src/tools/lint-docs/src/groups.rs
index 73f5738469ed1..f246d71d499b4 100644
--- a/src/tools/lint-docs/src/groups.rs
+++ b/src/tools/lint-docs/src/groups.rs
@@ -121,13 +121,13 @@ impl<'a> LintExtractor<'a> {
             };
             to_link.extend(group_lints);
             let brackets: Vec<_> = group_lints.iter().map(|l| format!("[{}]", l)).collect();
-            write!(result, "| {} | {} | {} |\n", group_name, description, brackets.join(", "))
+            writeln!(result, "| {} | {} | {} |", group_name, description, brackets.join(", "))
                 .unwrap();
         }
         result.push('\n');
         result.push_str("[warn-by-default]: listing/warn-by-default.md\n");
         for lint_name in to_link {
-            let lint_def = match lints.iter().find(|l| l.name == lint_name.replace("-", "_")) {
+            let lint_def = match lints.iter().find(|l| l.name == lint_name.replace('-', "_")) {
                 Some(def) => def,
                 None => {
                     let msg = format!(
@@ -144,9 +144,9 @@ impl<'a> LintExtractor<'a> {
                     }
                 }
             };
-            write!(
+            writeln!(
                 result,
-                "[{}]: listing/{}#{}\n",
+                "[{}]: listing/{}#{}",
                 lint_name,
                 lint_def.level.doc_filename(),
                 lint_name
diff --git a/src/tools/lint-docs/src/lib.rs b/src/tools/lint-docs/src/lib.rs
index c79b377727abf..72d6a495e7e79 100644
--- a/src/tools/lint-docs/src/lib.rs
+++ b/src/tools/lint-docs/src/lib.rs
@@ -84,8 +84,8 @@ impl Lint {
         for &expected in &["### Example", "### Explanation", "{{produces}}"] {
             if expected == "{{produces}}" && self.is_ignored() {
                 if self.doc_contains("{{produces}}") {
-                    return Err(format!(
-                        "the lint example has `ignore`, but also contains the {{{{produces}}}} marker\n\
+                    return Err(
+                        "the lint example has `ignore`, but also contains the {{produces}} marker\n\
                         \n\
                         The documentation generator cannot generate the example output when the \
                         example is ignored.\n\
@@ -111,7 +111,7 @@ impl Lint {
                         Replacing the output with the text of the example you \
                         compiled manually yourself.\n\
                         "
-                    ).into());
+                    .into());
                 }
                 continue;
             }
@@ -519,11 +519,11 @@ impl<'a> LintExtractor<'a> {
         let mut these_lints: Vec<_> = lints.iter().filter(|lint| lint.level == level).collect();
         these_lints.sort_unstable_by_key(|lint| &lint.name);
         for lint in &these_lints {
-            write!(result, "* [`{}`](#{})\n", lint.name, lint.name.replace("_", "-")).unwrap();
+            writeln!(result, "* [`{}`](#{})", lint.name, lint.name.replace('_', "-")).unwrap();
         }
         result.push('\n');
         for lint in &these_lints {
-            write!(result, "## {}\n\n", lint.name.replace("_", "-")).unwrap();
+            write!(result, "## {}\n\n", lint.name.replace('_', "-")).unwrap();
             for line in &lint.doc {
                 result.push_str(line);
                 result.push('\n');
@@ -583,7 +583,7 @@ fn add_rename_redirect(level: Level, output: &mut String) {
             let filename = level.doc_filename().replace(".md", ".html");
             output.push_str(RENAME_START);
             for (from, to) in *names {
-                write!(output, "        \"#{from}\": \"{filename}#{to}\",\n").unwrap();
+                writeln!(output, "        \"#{from}\": \"{filename}#{to}\",").unwrap();
             }
             output.push_str(RENAME_END);
         }
diff --git a/src/tools/opt-dist/src/training.rs b/src/tools/opt-dist/src/training.rs
index 89f4d8957c8bf..1237951b3f042 100644
--- a/src/tools/opt-dist/src/training.rs
+++ b/src/tools/opt-dist/src/training.rs
@@ -216,11 +216,9 @@ pub fn gather_bolt_profiles(
     log::info!("Profile file count: {}", profiles.len());
 
     // Delete the gathered profiles
-    for profile in glob::glob(&format!("{profile_prefix}*"))?.into_iter() {
-        if let Ok(profile) = profile {
-            if let Err(error) = std::fs::remove_file(&profile) {
-                log::error!("Cannot delete BOLT profile {}: {error:?}", profile.display());
-            }
+    for profile in glob::glob(&format!("{profile_prefix}*"))?.flatten() {
+        if let Err(error) = std::fs::remove_file(&profile) {
+            log::error!("Cannot delete BOLT profile {}: {error:?}", profile.display());
         }
     }
 
diff --git a/src/tools/remote-test-client/src/main.rs b/src/tools/remote-test-client/src/main.rs
index 590c735596ed9..dd2c09c430b61 100644
--- a/src/tools/remote-test-client/src/main.rs
+++ b/src/tools/remote-test-client/src/main.rs
@@ -317,13 +317,11 @@ fn run(support_lib_count: usize, exe: String, all_args: Vec<String>) {
                 t!(io::copy(&mut (&mut client).take(amt), &mut stdout));
                 t!(stdout.flush());
             }
+        } else if amt == 0 {
+            stderr_done = true;
         } else {
-            if amt == 0 {
-                stderr_done = true;
-            } else {
-                t!(io::copy(&mut (&mut client).take(amt), &mut stderr));
-                t!(stderr.flush());
-            }
+            t!(io::copy(&mut (&mut client).take(amt), &mut stderr));
+            t!(stderr.flush());
         }
     }
 
diff --git a/src/tools/remote-test-server/src/main.rs b/src/tools/remote-test-server/src/main.rs
index 68d7aa56c438b..79f96c5022382 100644
--- a/src/tools/remote-test-server/src/main.rs
+++ b/src/tools/remote-test-server/src/main.rs
@@ -282,7 +282,7 @@ fn handle_run(socket: TcpStream, work: &Path, tmp: &Path, lock: &Mutex<()>, conf
     cmd.env(library_path, env::join_paths(paths).unwrap());
 
     // Some tests assume RUST_TEST_TMPDIR exists
-    cmd.env("RUST_TEST_TMPDIR", tmp.to_owned());
+    cmd.env("RUST_TEST_TMPDIR", tmp);
 
     let socket = Arc::new(Mutex::new(reader.into_inner()));
 
diff --git a/src/tools/tidy/src/alphabetical.rs b/src/tools/tidy/src/alphabetical.rs
index 150a9594350ed..a29286fa2c596 100644
--- a/src/tools/tidy/src/alphabetical.rs
+++ b/src/tools/tidy/src/alphabetical.rs
@@ -88,7 +88,7 @@ fn check_section<'a>(
         let trimmed_line = line.trim_start_matches(' ');
 
         if trimmed_line.starts_with("//")
-            || (trimmed_line.starts_with("#") && !trimmed_line.starts_with("#!"))
+            || (trimmed_line.starts_with('#') && !trimmed_line.starts_with("#!"))
             || trimmed_line.starts_with(is_close_bracket)
         {
             continue;
diff --git a/src/tools/tidy/src/bins.rs b/src/tools/tidy/src/bins.rs
index 64ba79dc1857e..c82e8b6fee98e 100644
--- a/src/tools/tidy/src/bins.rs
+++ b/src/tools/tidy/src/bins.rs
@@ -61,7 +61,7 @@ mod os_impl {
                     fs::remove_file(&path).expect("Deleted temp file");
                     // If the file is executable, then we assume that this
                     // filesystem does not track executability, so skip this check.
-                    return if exec { Unsupported } else { Supported };
+                    if exec { Unsupported } else { Supported }
                 }
                 Err(e) => {
                     // If the directory is read-only or we otherwise don't have rights,
@@ -76,7 +76,7 @@ mod os_impl {
 
                     panic!("unable to create temporary file `{:?}`: {:?}", path, e);
                 }
-            };
+            }
         }
 
         for &source_dir in sources {
@@ -92,7 +92,7 @@ mod os_impl {
             }
         }
 
-        return true;
+        true
     }
 
     // FIXME: check when rust-installer test sh files will be removed,
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 2dd3d17f9e3e7..7337c9843c7b6 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -699,11 +699,9 @@ fn check_permitted_dependencies(
     for dep in deps {
         let dep = pkg_from_id(metadata, dep);
         // If this path is in-tree, we don't require it to be explicitly permitted.
-        if dep.source.is_some() {
-            if !permitted_dependencies.contains(dep.name.as_str()) {
-                tidy_error!(bad, "Dependency for {descr} not explicitly permitted: {}", dep.id);
-                has_permitted_dep_error = true;
-            }
+        if dep.source.is_some() && !permitted_dependencies.contains(dep.name.as_str()) {
+            tidy_error!(bad, "Dependency for {descr} not explicitly permitted: {}", dep.id);
+            has_permitted_dep_error = true;
         }
     }
 
diff --git a/src/tools/tidy/src/error_codes.rs b/src/tools/tidy/src/error_codes.rs
index 39f7e70b69393..47e2be761e6ab 100644
--- a/src/tools/tidy/src/error_codes.rs
+++ b/src/tools/tidy/src/error_codes.rs
@@ -308,11 +308,9 @@ fn check_error_codes_tests(
         for line in file.lines() {
             let s = line.trim();
             // Assuming the line starts with `error[E`, we can substring the error code out.
-            if s.starts_with("error[E") {
-                if &s[6..11] == code {
-                    found_code = true;
-                    break;
-                }
+            if s.starts_with("error[E") && &s[6..11] == code {
+                found_code = true;
+                break;
             };
         }
 
diff --git a/src/tools/tidy/src/ext_tool_checks.rs b/src/tools/tidy/src/ext_tool_checks.rs
index 2c97a39f1008b..d4b23971f6eb8 100644
--- a/src/tools/tidy/src/ext_tool_checks.rs
+++ b/src/tools/tidy/src/ext_tool_checks.rs
@@ -78,9 +78,9 @@ fn check_impl(
     let mut py_path = None;
 
     let (cfg_args, file_args): (Vec<_>, Vec<_>) = pos_args
-        .into_iter()
+        .iter()
         .map(OsStr::new)
-        .partition(|arg| arg.to_str().is_some_and(|s| s.starts_with("-")));
+        .partition(|arg| arg.to_str().is_some_and(|s| s.starts_with('-')));
 
     if python_lint || python_fmt {
         let venv_path = outdir.join("venv");
@@ -275,10 +275,11 @@ fn create_venv_at_path(path: &Path) -> Result<(), Error> {
         return Ok(());
     }
     let err = if String::from_utf8_lossy(&out.stderr).contains("No module named virtualenv") {
-        Error::Generic(format!(
+        Error::Generic(
             "virtualenv not found: you may need to install it \
                                (`python3 -m pip install venv`)"
-        ))
+                .to_owned(),
+        )
     } else {
         Error::Generic(format!("failed to create venv at '{}' using {sys_py}", path.display()))
     };
diff --git a/src/tools/tidy/src/style.rs b/src/tools/tidy/src/style.rs
index 2d3888ec75f25..7bcb85335e07d 100644
--- a/src/tools/tidy/src/style.rs
+++ b/src/tools/tidy/src/style.rs
@@ -463,10 +463,13 @@ pub fn check(path: &Path, bad: &mut bool) {
                 }
             }
             // for now we just check libcore
-            if trimmed.contains("unsafe {") && !trimmed.starts_with("//") && !last_safety_comment {
-                if file.components().any(|c| c.as_os_str() == "core") && !is_test {
-                    suppressible_tidy_err!(err, skip_undocumented_unsafe, "undocumented unsafe");
-                }
+            if trimmed.contains("unsafe {")
+                && !trimmed.starts_with("//")
+                && !last_safety_comment
+                && file.components().any(|c| c.as_os_str() == "core")
+                && !is_test
+            {
+                suppressible_tidy_err!(err, skip_undocumented_unsafe, "undocumented unsafe");
             }
             if trimmed.contains("// SAFETY:") {
                 last_safety_comment = true;
@@ -487,10 +490,10 @@ pub fn check(path: &Path, bad: &mut bool) {
                     "copyright notices attributed to the Rust Project Developers are deprecated"
                 );
             }
-            if !file.components().any(|c| c.as_os_str() == "rustc_baked_icu_data") {
-                if is_unexplained_ignore(&extension, line) {
-                    err(UNEXPLAINED_IGNORE_DOCTEST_INFO);
-                }
+            if !file.components().any(|c| c.as_os_str() == "rustc_baked_icu_data")
+                && is_unexplained_ignore(&extension, line)
+            {
+                err(UNEXPLAINED_IGNORE_DOCTEST_INFO);
             }
 
             if filename.ends_with(".cpp") && line.contains("llvm_unreachable") {
@@ -525,26 +528,24 @@ pub fn check(path: &Path, bad: &mut bool) {
                         backtick_count += comment_text.chars().filter(|ch| *ch == '`').count();
                     }
                     comment_block = Some((start_line, backtick_count));
-                } else {
-                    if let Some((start_line, backtick_count)) = comment_block.take() {
-                        if backtick_count % 2 == 1 {
-                            let mut err = |msg: &str| {
-                                tidy_error!(bad, "{}:{start_line}: {msg}", file.display());
-                            };
-                            let block_len = (i + 1) - start_line;
-                            if block_len == 1 {
-                                suppressible_tidy_err!(
-                                    err,
-                                    skip_odd_backticks,
-                                    "comment with odd number of backticks"
-                                );
-                            } else {
-                                suppressible_tidy_err!(
-                                    err,
-                                    skip_odd_backticks,
-                                    "{block_len}-line comment block with odd number of backticks"
-                                );
-                            }
+                } else if let Some((start_line, backtick_count)) = comment_block.take() {
+                    if backtick_count % 2 == 1 {
+                        let mut err = |msg: &str| {
+                            tidy_error!(bad, "{}:{start_line}: {msg}", file.display());
+                        };
+                        let block_len = (i + 1) - start_line;
+                        if block_len == 1 {
+                            suppressible_tidy_err!(
+                                err,
+                                skip_odd_backticks,
+                                "comment with odd number of backticks"
+                            );
+                        } else {
+                            suppressible_tidy_err!(
+                                err,
+                                skip_odd_backticks,
+                                "{block_len}-line comment block with odd number of backticks"
+                            );
                         }
                     }
                 }
diff --git a/src/tools/tidy/src/walk.rs b/src/tools/tidy/src/walk.rs
index 63a0383416652..1cecf998e284b 100644
--- a/src/tools/tidy/src/walk.rs
+++ b/src/tools/tidy/src/walk.rs
@@ -79,13 +79,11 @@ pub(crate) fn walk_no_read(
     let walker = walker.filter_entry(move |e| {
         !skip(e.path(), e.file_type().map(|ft| ft.is_dir()).unwrap_or(false))
     });
-    for entry in walker.build() {
-        if let Ok(entry) = entry {
-            if entry.file_type().map_or(true, |kind| kind.is_dir() || kind.is_symlink()) {
-                continue;
-            }
-            f(&entry);
+    for entry in walker.build().flatten() {
+        if entry.file_type().map_or(true, |kind| kind.is_dir() || kind.is_symlink()) {
+            continue;
         }
+        f(&entry);
     }
 }
 
@@ -97,11 +95,9 @@ pub(crate) fn walk_dir(
 ) {
     let mut walker = ignore::WalkBuilder::new(path);
     let walker = walker.filter_entry(move |e| !skip(e.path()));
-    for entry in walker.build() {
-        if let Ok(entry) = entry {
-            if entry.path().is_dir() {
-                f(&entry);
-            }
+    for entry in walker.build().flatten() {
+        if entry.path().is_dir() {
+            f(&entry);
         }
     }
 }
diff --git a/src/tools/tidy/src/x_version.rs b/src/tools/tidy/src/x_version.rs
index c470d502a6548..55bfbed8b0e10 100644
--- a/src/tools/tidy/src/x_version.rs
+++ b/src/tools/tidy/src/x_version.rs
@@ -52,7 +52,7 @@ pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
             );
         }
     } else {
-        return tidy_error!(bad, "failed to check version of `x`: {}", cargo_list.status);
+        tidy_error!(bad, "failed to check version of `x`: {}", cargo_list.status)
     }
 }
 
diff --git a/tests/codegen/instrument-coverage/instrument-coverage-off.rs b/tests/codegen/instrument-coverage/instrument-coverage-off.rs
index 616e3295e5b1a..e44d6c6587480 100644
--- a/tests/codegen/instrument-coverage/instrument-coverage-off.rs
+++ b/tests/codegen/instrument-coverage/instrument-coverage-off.rs
@@ -1,5 +1,6 @@
 // Test that `-Cinstrument-coverage=off` does not add coverage instrumentation to LLVM IR.
 
+//@ compile-flags: -Zno-profiler-runtime
 //@ revisions: n no off false_ zero
 //@ [n] compile-flags: -Cinstrument-coverage=n
 //@ [no] compile-flags: -Cinstrument-coverage=no
diff --git a/tests/codegen/instrument-coverage/instrument-coverage.rs b/tests/codegen/instrument-coverage/instrument-coverage.rs
index 65fa437d25066..3c16208d40e78 100644
--- a/tests/codegen/instrument-coverage/instrument-coverage.rs
+++ b/tests/codegen/instrument-coverage/instrument-coverage.rs
@@ -1,6 +1,6 @@
 // Test that `-Cinstrument-coverage` creates expected __llvm_profile_filename symbol in LLVM IR.
 
-//@ needs-profiler-support
+//@ compile-flags: -Zno-profiler-runtime
 //@ revisions: default y yes on true_ all
 //@ [default] compile-flags: -Cinstrument-coverage
 //@ [y] compile-flags: -Cinstrument-coverage=y
diff --git a/tests/codegen/instrument-coverage/testprog.rs b/tests/codegen/instrument-coverage/testprog.rs
index acc4f35d90543..eea4d9cb3cf05 100644
--- a/tests/codegen/instrument-coverage/testprog.rs
+++ b/tests/codegen/instrument-coverage/testprog.rs
@@ -1,5 +1,5 @@
 //@ edition: 2021
-//@ needs-profiler-support
+//@ compile-flags: -Zno-profiler-runtime
 //@ compile-flags: -Cinstrument-coverage -Copt-level=0
 //@ revisions: LINUX DARWIN WINDOWS
 
diff --git a/tests/codegen/naked-fn/naked-nocoverage.rs b/tests/codegen/naked-fn/naked-nocoverage.rs
index e8d3b5834fa3a..d73c5b7fd26d1 100644
--- a/tests/codegen/naked-fn/naked-nocoverage.rs
+++ b/tests/codegen/naked-fn/naked-nocoverage.rs
@@ -2,7 +2,7 @@
 // Regression test for issue #105170.
 //
 //@ needs-asm-support
-//@ needs-profiler-support
+//@ compile-flags: -Zno-profiler-runtime
 //@ compile-flags: -Cinstrument-coverage
 #![crate_type = "lib"]
 #![feature(naked_functions)]
diff --git a/tests/codegen/pgo-counter-bias.rs b/tests/codegen/pgo-counter-bias.rs
index 87d31073d5ae1..48e815dda0483 100644
--- a/tests/codegen/pgo-counter-bias.rs
+++ b/tests/codegen/pgo-counter-bias.rs
@@ -2,7 +2,7 @@
 
 //@ ignore-apple -runtime-counter-relocation not honored on Mach-O
 //@ compile-flags: -Cprofile-generate -Cllvm-args=-runtime-counter-relocation -Clto=fat
-//@ needs-profiler-support
+//@ compile-flags: -Zno-profiler-runtime
 //@ no-prefer-dynamic
 
 // CHECK: @__llvm_profile_counter_bias = {{.*}}global
diff --git a/tests/codegen/pgo-instrumentation.rs b/tests/codegen/pgo-instrumentation.rs
index b1906c145c6be..a8f12ccce1cb4 100644
--- a/tests/codegen/pgo-instrumentation.rs
+++ b/tests/codegen/pgo-instrumentation.rs
@@ -1,6 +1,6 @@
 // Test that `-Cprofile-generate` creates expected instrumentation artifacts in LLVM IR.
 
-//@ needs-profiler-support
+//@ compile-flags: -Zno-profiler-runtime
 //@ compile-flags: -Cprofile-generate -Ccodegen-units=1
 
 // CHECK: @__llvm_profile_raw_version =
diff --git a/tests/crashes/109812.rs b/tests/crashes/109812.rs
deleted file mode 100644
index c29b874652153..0000000000000
--- a/tests/crashes/109812.rs
+++ /dev/null
@@ -1,22 +0,0 @@
-//@ known-bug: #109812
-
-#![warn(rust_2021_incompatible_closure_captures)]
-
-enum Either {
-    One(X),
-    Two(X),
-}
-
-struct X(Y);
-
-struct Y;
-
-fn move_into_fnmut() {
-    let x = X(Y);
-
-    consume_fnmut(|| {
-        let Either::Two(ref mut _t) = x;
-
-        let X(mut _t) = x;
-    });
-}
diff --git a/tests/crashes/125914.rs b/tests/crashes/125914.rs
deleted file mode 100644
index 77ccb9fb0978d..0000000000000
--- a/tests/crashes/125914.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-//@ known-bug: rust-lang/rust#125914
-enum AstKind<'ast> {
-    ExprInt,
-}
-
-enum Foo {
-    Bar(isize),
-    Baz,
-}
-
-enum Other {
-    Other1(Foo),
-    Other2(AstKind),
-}
-
-fn main() {
-    match Other::Other1(Foo::Baz) {
-        ::Other::Other2(::Foo::Bar(..)) => {}
-    }
-}
diff --git a/tests/run-make/optimization-remarks-dir-pgo/Makefile b/tests/run-make/optimization-remarks-dir-pgo/Makefile
index 3bc3d7d142887..57ffd6e70f00b 100644
--- a/tests/run-make/optimization-remarks-dir-pgo/Makefile
+++ b/tests/run-make/optimization-remarks-dir-pgo/Makefile
@@ -1,10 +1,6 @@
 # needs-profiler-support
-# ignore-windows-gnu
 # ignore-cross-compile
 
-# FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-# properly. Since we only have GCC on the CI ignore the test for now.
-
 include ../tools.mk
 
 PROFILE_DIR=$(TMPDIR)/profiles
diff --git a/tests/run-make/pgo-branch-weights/rmake.rs b/tests/run-make/pgo-branch-weights/rmake.rs
index 55f6e7e56c5ae..d3cb79c39afa9 100644
--- a/tests/run-make/pgo-branch-weights/rmake.rs
+++ b/tests/run-make/pgo-branch-weights/rmake.rs
@@ -10,10 +10,6 @@
 //@ needs-profiler-support
 //@ ignore-cross-compile
 
-// FIXME(Oneirical): This test has problems generating profdata on mingw.
-// For more information, see https://github.com/rust-lang/rust/pull/122613
-//@ ignore-windows-gnu
-
 use run_make_support::{fs_wrapper, llvm_filecheck, llvm_profdata, run_with_args, rustc};
 use std::path::Path;
 
diff --git a/tests/run-make/pgo-gen-lto/Makefile b/tests/run-make/pgo-gen-lto/Makefile
index 8b647846af3b3..54164c995222a 100644
--- a/tests/run-make/pgo-gen-lto/Makefile
+++ b/tests/run-make/pgo-gen-lto/Makefile
@@ -1,10 +1,6 @@
 # needs-profiler-support
-# ignore-windows-gnu
 # ignore-cross-compile
 
-# FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-# properly. Since we only have GCC on the CI ignore the test for now.
-
 include ../tools.mk
 
 COMPILE_FLAGS=-Copt-level=3 -Clto=fat -Cprofile-generate="$(TMPDIR)"
diff --git a/tests/run-make/pgo-gen-no-imp-symbols/Makefile b/tests/run-make/pgo-gen-no-imp-symbols/Makefile
index 7f72b11b611ed..d2baa145ba506 100644
--- a/tests/run-make/pgo-gen-no-imp-symbols/Makefile
+++ b/tests/run-make/pgo-gen-no-imp-symbols/Makefile
@@ -1,8 +1,6 @@
-# needs-profiler-support
-
 include ../tools.mk
 
-COMPILE_FLAGS=-O -Ccodegen-units=1 -Cprofile-generate="$(TMPDIR)"
+COMPILE_FLAGS=-O -Ccodegen-units=1 -Cprofile-generate="$(TMPDIR)" -Zno-profiler-runtime
 
 all:
 	$(RUSTC) $(COMPILE_FLAGS) --emit=llvm-ir test.rs
diff --git a/tests/run-make/pgo-gen/Makefile b/tests/run-make/pgo-gen/Makefile
index bf32cfdb802f5..c1d456986fb28 100644
--- a/tests/run-make/pgo-gen/Makefile
+++ b/tests/run-make/pgo-gen/Makefile
@@ -1,10 +1,6 @@
 # needs-profiler-support
-# ignore-windows-gnu
 # ignore-cross-compile
 
-# FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-# properly. Since we only have GCC on the CI ignore the test for now.
-
 include ../tools.mk
 
 COMPILE_FLAGS=-g -Cprofile-generate="$(TMPDIR)"
diff --git a/tests/run-make/pgo-indirect-call-promotion/Makefile b/tests/run-make/pgo-indirect-call-promotion/Makefile
index 542eb244d3959..8d1e69c4aba37 100644
--- a/tests/run-make/pgo-indirect-call-promotion/Makefile
+++ b/tests/run-make/pgo-indirect-call-promotion/Makefile
@@ -1,10 +1,6 @@
 # needs-profiler-support
-# ignore-windows-gnu
 # ignore-cross-compile
 
-# FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-# properly. Since we only have GCC on the CI ignore the test for now.
-
 include ../tools.mk
 
 all:
diff --git a/tests/run-make/pgo-use/Makefile b/tests/run-make/pgo-use/Makefile
index 9f440118daee3..92098a4019c47 100644
--- a/tests/run-make/pgo-use/Makefile
+++ b/tests/run-make/pgo-use/Makefile
@@ -1,10 +1,6 @@
 # needs-profiler-support
-# ignore-windows-gnu
 # ignore-cross-compile
 
-# FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
-# properly. Since we only have GCC on the CI ignore the test for now.
-
 include ../tools.mk
 
 # This test makes sure that PGO profiling data leads to cold functions being
diff --git a/tests/run-make/track-pgo-dep-info/Makefile b/tests/run-make/track-pgo-dep-info/Makefile
index 6c7f67d0f0a9d..3afe3662fa753 100644
--- a/tests/run-make/track-pgo-dep-info/Makefile
+++ b/tests/run-make/track-pgo-dep-info/Makefile
@@ -1,5 +1,4 @@
 # needs-profiler-support
-# ignore-windows-gnu
 
 include ../tools.mk
 
diff --git a/tests/ui/impl-trait/call_method_ambiguous.next.stderr b/tests/ui/impl-trait/call_method_ambiguous.next.stderr
new file mode 100644
index 0000000000000..cd222aa7ae9fc
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_ambiguous.next.stderr
@@ -0,0 +1,17 @@
+error[E0282]: type annotations needed
+  --> $DIR/call_method_ambiguous.rs:29:13
+   |
+LL |         let mut iter = foo(n - 1, m);
+   |             ^^^^^^^^
+LL |
+LL |         assert_eq!(iter.get(), 1);
+   |                    ---- type must be known at this point
+   |
+help: consider giving `iter` an explicit type
+   |
+LL |         let mut iter: /* Type */ = foo(n - 1, m);
+   |                     ++++++++++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/impl-trait/call_method_ambiguous.rs b/tests/ui/impl-trait/call_method_ambiguous.rs
new file mode 100644
index 0000000000000..c26c01e002d85
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_ambiguous.rs
@@ -0,0 +1,39 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@[current] run-pass
+
+#![feature(precise_capturing)]
+#![allow(incomplete_features)]
+
+trait Get {
+    fn get(&mut self) -> u32;
+}
+
+impl Get for () {
+    fn get(&mut self) -> u32 {
+        0
+    }
+}
+
+impl<T> Get for &mut T
+where
+    T: Get,
+{
+    fn get(&mut self) -> u32 {
+        T::get(self) + 1
+    }
+}
+
+fn foo(n: usize, m: &mut ()) -> impl use<'_> Get {
+    if n > 0 {
+        let mut iter = foo(n - 1, m);
+        //[next]~^ type annotations needed
+        assert_eq!(iter.get(), 1);
+    }
+    m
+}
+
+fn main() {
+    let g = foo(1, &mut ()).get();
+    assert_eq!(g, 1);
+}
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl.next.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl.next.stderr
new file mode 100644
index 0000000000000..271051f120abc
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl.next.stderr
@@ -0,0 +1,17 @@
+error[E0282]: type annotations needed
+  --> $DIR/call_method_on_inherent_impl.rs:18:13
+   |
+LL |         let x = my_foo();
+   |             ^
+LL |
+LL |         x.my_debug();
+   |         - type must be known at this point
+   |
+help: consider giving `x` an explicit type
+   |
+LL |         let x: /* Type */ = my_foo();
+   |              ++++++++++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl.rs b/tests/ui/impl-trait/call_method_on_inherent_impl.rs
new file mode 100644
index 0000000000000..17f7cad660db1
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl.rs
@@ -0,0 +1,25 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@[current] check-pass
+
+trait MyDebug {
+    fn my_debug(&self);
+}
+
+impl<T> MyDebug for T
+where
+    T: std::fmt::Debug,
+{
+    fn my_debug(&self) {}
+}
+
+fn my_foo() -> impl std::fmt::Debug {
+    if false {
+        let x = my_foo();
+        //[next]~^ type annotations needed
+        x.my_debug();
+    }
+    ()
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.current.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.current.stderr
new file mode 100644
index 0000000000000..6ecb2b05fc56b
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.current.stderr
@@ -0,0 +1,16 @@
+error[E0599]: no method named `my_debug` found for reference `&impl Debug` in the current scope
+  --> $DIR/call_method_on_inherent_impl_on_rigid_type.rs:16:11
+   |
+LL |         x.my_debug();
+   |           ^^^^^^^^ method not found in `&impl Debug`
+   |
+   = help: items from traits can only be used if the trait is implemented and in scope
+note: `MyDebug` defines an item `my_debug`, perhaps you need to implement it
+  --> $DIR/call_method_on_inherent_impl_on_rigid_type.rs:4:1
+   |
+LL | trait MyDebug {
+   | ^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.next.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.next.stderr
new file mode 100644
index 0000000000000..5fb0b8f1d14b2
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.next.stderr
@@ -0,0 +1,17 @@
+error[E0282]: type annotations needed for `&_`
+  --> $DIR/call_method_on_inherent_impl_on_rigid_type.rs:14:13
+   |
+LL |         let x = &my_foo();
+   |             ^
+LL |
+LL |         x.my_debug();
+   |           -------- type must be known at this point
+   |
+help: consider giving `x` an explicit type, where the placeholders `_` are specified
+   |
+LL |         let x: &_ = &my_foo();
+   |              ++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.rs b/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.rs
new file mode 100644
index 0000000000000..7fb2ff3b2bcc6
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl_on_rigid_type.rs
@@ -0,0 +1,22 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+trait MyDebug {
+    fn my_debug(&self);
+}
+
+impl MyDebug for &() {
+    fn my_debug(&self) {}
+}
+
+fn my_foo() -> impl std::fmt::Debug {
+    if false {
+        let x = &my_foo();
+        //[next]~^ ERROR: type annotations needed
+        x.my_debug();
+        //[current]~^ ERROR: no method named `my_debug`
+    }
+    ()
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_ref.current.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.current.stderr
new file mode 100644
index 0000000000000..fe6e166cb4fa1
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.current.stderr
@@ -0,0 +1,40 @@
+error[E0599]: no method named `my_debug` found for opaque type `impl Debug` in the current scope
+  --> $DIR/call_method_on_inherent_impl_ref.rs:20:11
+   |
+LL |     fn my_debug(&self);
+   |        -------- the method is available for `&impl Debug` here
+...
+LL |         x.my_debug();
+   |           ^^^^^^^^ method not found in `impl Debug`
+   |
+   = help: items from traits can only be used if the trait is implemented and in scope
+note: `MyDebug` defines an item `my_debug`, perhaps you need to implement it
+  --> $DIR/call_method_on_inherent_impl_ref.rs:4:1
+   |
+LL | trait MyDebug {
+   | ^^^^^^^^^^^^^
+
+error[E0391]: cycle detected when computing type of opaque `my_foo::{opaque#0}`
+  --> $DIR/call_method_on_inherent_impl_ref.rs:15:16
+   |
+LL | fn my_foo() -> impl std::fmt::Debug {
+   |                ^^^^^^^^^^^^^^^^^^^^
+   |
+note: ...which requires type-checking `my_foo`...
+  --> $DIR/call_method_on_inherent_impl_ref.rs:20:9
+   |
+LL |         x.my_debug();
+   |         ^
+   = note: ...which requires evaluating trait selection obligation `my_foo::{opaque#0}: core::marker::Unpin`...
+   = note: ...which again requires computing type of opaque `my_foo::{opaque#0}`, completing the cycle
+note: cycle used when computing type of `my_foo::{opaque#0}`
+  --> $DIR/call_method_on_inherent_impl_ref.rs:15:16
+   |
+LL | fn my_foo() -> impl std::fmt::Debug {
+   |                ^^^^^^^^^^^^^^^^^^^^
+   = 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 2 previous errors
+
+Some errors have detailed explanations: E0391, E0599.
+For more information about an error, try `rustc --explain E0391`.
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_ref.next.stderr b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.next.stderr
new file mode 100644
index 0000000000000..327f6ca3450f1
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.next.stderr
@@ -0,0 +1,31 @@
+error[E0282]: type annotations needed
+  --> $DIR/call_method_on_inherent_impl_ref.rs:18:13
+   |
+LL |         let x = my_foo();
+   |             ^
+LL |
+LL |         x.my_debug();
+   |         - type must be known at this point
+   |
+help: consider giving `x` an explicit type
+   |
+LL |         let x: /* Type */ = my_foo();
+   |              ++++++++++++
+
+error[E0282]: type annotations needed for `&_`
+  --> $DIR/call_method_on_inherent_impl_ref.rs:28:13
+   |
+LL |         let x = &my_bar();
+   |             ^
+LL |
+LL |         x.my_debug();
+   |           -------- type must be known at this point
+   |
+help: consider giving `x` an explicit type, where the placeholders `_` are specified
+   |
+LL |         let x: &_ = &my_bar();
+   |              ++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/impl-trait/call_method_on_inherent_impl_ref.rs b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.rs
new file mode 100644
index 0000000000000..40ad21532a4e2
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_on_inherent_impl_ref.rs
@@ -0,0 +1,35 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+trait MyDebug {
+    fn my_debug(&self);
+}
+
+impl<T> MyDebug for &T
+where
+    T: std::fmt::Debug,
+{
+    fn my_debug(&self) {}
+}
+
+fn my_foo() -> impl std::fmt::Debug {
+    //[current]~^ cycle
+    if false {
+        let x = my_foo();
+        //[next]~^ type annotations needed
+        x.my_debug();
+        //[current]~^ no method named `my_debug` found
+    }
+    ()
+}
+
+fn my_bar() -> impl std::fmt::Debug {
+    if false {
+        let x = &my_bar();
+        //[next]~^ type annotations needed
+        x.my_debug();
+    }
+    ()
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/call_method_without_import.no_import.stderr b/tests/ui/impl-trait/call_method_without_import.no_import.stderr
new file mode 100644
index 0000000000000..72982b695bbb0
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_without_import.no_import.stderr
@@ -0,0 +1,37 @@
+error[E0599]: no method named `fmt` found for opaque type `impl Debug` in the current scope
+  --> $DIR/call_method_without_import.rs:17:11
+   |
+LL |         x.fmt(f);
+   |           ^^^ method not found in `impl Debug`
+  --> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
+   |
+   = note: the method is available for `impl Debug` here
+   |
+   = help: items from traits can only be used if the trait is in scope
+help: trait `Debug` which provides `fmt` is implemented but not in scope; perhaps you want to import it
+   |
+LL + use std::fmt::Debug;
+   |
+
+error[E0599]: no method named `fmt` found for mutable reference `&mut impl Debug` in the current scope
+  --> $DIR/call_method_without_import.rs:26:11
+   |
+LL |         x.fmt(f);
+   |           ^^^ method not found in `&mut impl Debug`
+   |
+   = help: items from traits can only be used if the trait is in scope
+help: the following traits which provide `fmt` are implemented but not in scope; perhaps you want to import one of them
+   |
+LL + use std::fmt::Binary;
+   |
+LL + use std::fmt::Debug;
+   |
+LL + use std::fmt::Display;
+   |
+LL + use std::fmt::LowerExp;
+   |
+     and 5 other candidates
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/impl-trait/call_method_without_import.rs b/tests/ui/impl-trait/call_method_without_import.rs
new file mode 100644
index 0000000000000..d62777ea2835d
--- /dev/null
+++ b/tests/ui/impl-trait/call_method_without_import.rs
@@ -0,0 +1,42 @@
+//! Test that opaque types only pick up methods from traits in their bounds
+//! if the trait is imported.
+//!
+//! FIXME: always look through the bounds of an opaque type to see if there are
+//! methods that could be called on any of the bound traits, irrespective of
+//! imported traits.
+
+//@ revisions: import no_import
+//@[import] check-pass
+
+#[cfg(import)]
+use std::fmt::Debug as _;
+
+fn foo(f: &mut std::fmt::Formatter<'_>) -> impl std::fmt::Debug {
+    if false {
+        let x = foo(f);
+        x.fmt(f);
+        //[no_import]~^ ERROR: no method named `fmt` found
+    }
+    ()
+}
+
+fn foo1(f: &mut std::fmt::Formatter<'_>) -> impl std::fmt::Debug {
+    if false {
+        let x = &mut foo(f);
+        x.fmt(f);
+        //[no_import]~^ ERROR: no method named `fmt` found
+    }
+    ()
+}
+
+// inconsistent with this
+fn bar<T>(t: impl std::fmt::Debug, f: &mut std::fmt::Formatter<'_>) {
+    t.fmt(f);
+}
+
+// and the desugared version, of course
+fn baz<T: std::fmt::Debug>(t: T, f: &mut std::fmt::Formatter<'_>) {
+    t.fmt(f);
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/method-resolution.rs b/tests/ui/impl-trait/method-resolution.rs
new file mode 100644
index 0000000000000..60fbacd86462b
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution.rs
@@ -0,0 +1,26 @@
+//! Since there is only one possible `bar` method, we invoke it and subsequently
+//! constrain `foo`'s RPIT to `u32`.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+trait Trait {}
+
+impl Trait for u32 {}
+
+struct Bar<T>(T);
+
+impl Bar<u32> {
+    fn bar(self) {}
+}
+
+fn foo(x: bool) -> Bar<impl Sized> {
+    if x {
+        let x = foo(false);
+        x.bar();
+    }
+    todo!()
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/method-resolution2.next.stderr b/tests/ui/impl-trait/method-resolution2.next.stderr
new file mode 100644
index 0000000000000..223430e1658b4
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution2.next.stderr
@@ -0,0 +1,20 @@
+error[E0034]: multiple applicable items in scope
+  --> $DIR/method-resolution2.rs:25:11
+   |
+LL |         x.bar();
+   |           ^^^ multiple `bar` found
+   |
+note: candidate #1 is defined in an impl for the type `Bar<T>`
+  --> $DIR/method-resolution2.rs:19:5
+   |
+LL |     fn bar(self) {}
+   |     ^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `Bar<u32>`
+  --> $DIR/method-resolution2.rs:15:5
+   |
+LL |     fn bar(self) {}
+   |     ^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0034`.
diff --git a/tests/ui/impl-trait/method-resolution2.rs b/tests/ui/impl-trait/method-resolution2.rs
new file mode 100644
index 0000000000000..88d4f3d9896c7
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution2.rs
@@ -0,0 +1,31 @@
+//! Check that the method call does not constrain the RPIT to `i32`, even though
+//! `i32` is the only type that satisfies the RPIT's trait bounds.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@[current] check-pass
+
+trait Trait {}
+
+impl Trait for i32 {}
+
+struct Bar<T>(T);
+
+impl Bar<u32> {
+    fn bar(self) {}
+}
+
+impl<T: Trait> Bar<T> {
+    fn bar(self) {}
+}
+
+fn foo(x: bool) -> Bar<impl Trait> {
+    if x {
+        let x = foo(false);
+        x.bar();
+        //[next]~^ ERROR: multiple applicable items in scope
+    }
+    Bar(42_i32)
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/method-resolution3.current.stderr b/tests/ui/impl-trait/method-resolution3.current.stderr
new file mode 100644
index 0000000000000..87dd862ef8f4f
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution3.current.stderr
@@ -0,0 +1,20 @@
+error[E0034]: multiple applicable items in scope
+  --> $DIR/method-resolution3.rs:21:11
+   |
+LL |         x.bar();
+   |           ^^^ multiple `bar` found
+   |
+note: candidate #1 is defined in an impl for the type `Bar<i32>`
+  --> $DIR/method-resolution3.rs:15:5
+   |
+LL |     fn bar(self) {}
+   |     ^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `Bar<u32>`
+  --> $DIR/method-resolution3.rs:11:5
+   |
+LL |     fn bar(self) {}
+   |     ^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0034`.
diff --git a/tests/ui/impl-trait/method-resolution3.next.stderr b/tests/ui/impl-trait/method-resolution3.next.stderr
new file mode 100644
index 0000000000000..87dd862ef8f4f
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution3.next.stderr
@@ -0,0 +1,20 @@
+error[E0034]: multiple applicable items in scope
+  --> $DIR/method-resolution3.rs:21:11
+   |
+LL |         x.bar();
+   |           ^^^ multiple `bar` found
+   |
+note: candidate #1 is defined in an impl for the type `Bar<i32>`
+  --> $DIR/method-resolution3.rs:15:5
+   |
+LL |     fn bar(self) {}
+   |     ^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `Bar<u32>`
+  --> $DIR/method-resolution3.rs:11:5
+   |
+LL |     fn bar(self) {}
+   |     ^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0034`.
diff --git a/tests/ui/impl-trait/method-resolution3.rs b/tests/ui/impl-trait/method-resolution3.rs
new file mode 100644
index 0000000000000..8c47ef4fc75c7
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution3.rs
@@ -0,0 +1,27 @@
+//! Check that we consider `Bar<impl Sized>` to successfully unify
+//! with both `Bar<u32>` and `Bar<i32>` (in isolation), so we bail
+//! out with ambiguity.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+struct Bar<T>(T);
+
+impl Bar<u32> {
+    fn bar(self) {}
+}
+
+impl Bar<i32> {
+    fn bar(self) {}
+}
+
+fn foo(x: bool) -> Bar<impl Sized> {
+    if x {
+        let x = foo(false);
+        x.bar();
+        //~^ ERROR: multiple applicable items in scope
+    }
+    todo!()
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/method-resolution4.next.stderr b/tests/ui/impl-trait/method-resolution4.next.stderr
new file mode 100644
index 0000000000000..b48de0af3579d
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution4.next.stderr
@@ -0,0 +1,22 @@
+error[E0282]: type annotations needed
+  --> $DIR/method-resolution4.rs:13:9
+   |
+LL |         foo(false).next().unwrap();
+   |         ^^^^^^^^^^ cannot infer type
+
+error[E0308]: mismatched types
+  --> $DIR/method-resolution4.rs:16:5
+   |
+LL | fn foo(b: bool) -> impl Iterator<Item = ()> {
+   |                    ------------------------ the expected opaque type
+...
+LL |     std::iter::empty()
+   |     ^^^^^^^^^^^^^^^^^^ types differ
+   |
+   = note: expected opaque type `impl Iterator<Item = ()>`
+                   found struct `std::iter::Empty<_>`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0282, E0308.
+For more information about an error, try `rustc --explain E0282`.
diff --git a/tests/ui/impl-trait/method-resolution4.rs b/tests/ui/impl-trait/method-resolution4.rs
new file mode 100644
index 0000000000000..91884eb59fd63
--- /dev/null
+++ b/tests/ui/impl-trait/method-resolution4.rs
@@ -0,0 +1,20 @@
+//! The recursive method call yields the opaque type. The
+//! `next` method call then constrains the hidden type to `&mut _`
+//! because `next` takes `&mut self`. We never resolve the inference
+//! variable, but get a type mismatch when comparing `&mut _` with
+//! `std::iter::Empty`.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@[current] check-pass
+
+fn foo(b: bool) -> impl Iterator<Item = ()> {
+    if b {
+        foo(false).next().unwrap();
+        //[next]~^ type annotations needed
+    }
+    std::iter::empty()
+    //[next]~^ mismatched types
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/recursive-parent-trait-method-call.rs b/tests/ui/impl-trait/recursive-parent-trait-method-call.rs
new file mode 100644
index 0000000000000..4da9a06a4659b
--- /dev/null
+++ b/tests/ui/impl-trait/recursive-parent-trait-method-call.rs
@@ -0,0 +1,42 @@
+//! This test checks that we can resolve the `boxed` method call to `FutureExt`,
+//! because we know that the anonymous future does not implement `StreamExt`.
+
+//@ edition: 2021
+//@ check-pass
+
+use std::future::Future;
+use std::pin::Pin;
+
+trait FutureExt: Future + Sized + Send + 'static {
+    fn boxed(self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'static>> {
+        Box::pin(self)
+    }
+}
+
+trait StreamExt: Future + Sized + Send + 'static {
+    fn boxed(self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'static>> {
+        Box::pin(self)
+    }
+}
+
+impl<T: Future + Sized + Send + 'static> FutureExt for T {}
+
+fn go(i: usize) -> impl Future<Output = ()> + Send + 'static {
+    async move {
+        if i != 0 {
+            spawn(async move {
+                let fut = go(i - 1).boxed();
+                fut.await;
+            })
+            .await;
+        }
+    }
+}
+
+pub fn spawn<T: Send>(
+    _: impl Future<Output = T> + Send + 'static,
+) -> impl Future<Output = ()> + Send + 'static {
+    async move { todo!() }
+}
+
+fn main() {}
diff --git a/tests/ui/instrument-coverage/coverage-options.rs b/tests/ui/instrument-coverage/coverage-options.rs
index 8f523a5fd11a0..7615a0fb2751c 100644
--- a/tests/ui/instrument-coverage/coverage-options.rs
+++ b/tests/ui/instrument-coverage/coverage-options.rs
@@ -1,6 +1,5 @@
-//@ needs-profiler-support
 //@ revisions: block branch condition mcdc bad
-//@ compile-flags -Cinstrument-coverage
+//@ compile-flags -Cinstrument-coverage -Zno-profiler-runtime
 
 //@ [block] check-pass
 //@ [block] compile-flags: -Zcoverage-options=block
diff --git a/tests/ui/instrument-coverage/on-values.rs b/tests/ui/instrument-coverage/on-values.rs
index a6793b2c304f2..53b149fd39cce 100644
--- a/tests/ui/instrument-coverage/on-values.rs
+++ b/tests/ui/instrument-coverage/on-values.rs
@@ -1,5 +1,5 @@
 //@ check-pass
-//@ needs-profiler-support
+//@ compile-flags: -Zno-profiler-runtime
 //@ revisions: default y yes on true_ all
 //@ [default] compile-flags: -Cinstrument-coverage
 //@ [y] compile-flags: -Cinstrument-coverage=y
diff --git a/tests/ui/methods/opaque_param_in_ufc.rs b/tests/ui/methods/opaque_param_in_ufc.rs
index a4b27a0131fd0..b170e6805f646 100644
--- a/tests/ui/methods/opaque_param_in_ufc.rs
+++ b/tests/ui/methods/opaque_param_in_ufc.rs
@@ -1,4 +1,7 @@
 #![feature(type_alias_impl_trait)]
+
+//@ check-pass
+
 struct Foo<T>(T);
 
 impl Foo<u32> {
@@ -15,14 +18,11 @@ fn bar() -> Bar {
 impl Foo<Bar> {
     fn foo() -> Bar {
         Self::method();
-        //~^ ERROR: no function or associated item named `method` found for struct `Foo<Bar>`
         Foo::<Bar>::method();
-        //~^ ERROR: no function or associated item named `method` found for struct `Foo<Bar>`
         let x = Foo(bar());
         Foo::method2(x);
         let x = Self(bar());
         Self::method2(x);
-        //~^ ERROR: no function or associated item named `method2` found for struct `Foo<Bar>`
         todo!()
     }
 }
diff --git a/tests/ui/methods/opaque_param_in_ufc.stderr b/tests/ui/methods/opaque_param_in_ufc.stderr
deleted file mode 100644
index 7e5bbbac8a9ab..0000000000000
--- a/tests/ui/methods/opaque_param_in_ufc.stderr
+++ /dev/null
@@ -1,36 +0,0 @@
-error[E0599]: no function or associated item named `method` found for struct `Foo<Bar>` in the current scope
-  --> $DIR/opaque_param_in_ufc.rs:17:15
-   |
-LL | struct Foo<T>(T);
-   | ------------- function or associated item `method` not found for this struct
-...
-LL |         Self::method();
-   |               ^^^^^^ function or associated item not found in `Foo<Bar>`
-   |
-   = note: the function or associated item was found for
-           - `Foo<u32>`
-
-error[E0599]: no function or associated item named `method` found for struct `Foo<Bar>` in the current scope
-  --> $DIR/opaque_param_in_ufc.rs:19:21
-   |
-LL | struct Foo<T>(T);
-   | ------------- function or associated item `method` not found for this struct
-...
-LL |         Foo::<Bar>::method();
-   |                     ^^^^^^ function or associated item not found in `Foo<Bar>`
-   |
-   = note: the function or associated item was found for
-           - `Foo<u32>`
-
-error[E0599]: no function or associated item named `method2` found for struct `Foo<Bar>` in the current scope
-  --> $DIR/opaque_param_in_ufc.rs:24:15
-   |
-LL | struct Foo<T>(T);
-   | ------------- function or associated item `method2` not found for this struct
-...
-LL |         Self::method2(x);
-   |               ^^^^^^^ function or associated item not found in `Foo<Bar>`
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/crashes/124004.rs b/tests/ui/pattern/box-pattern-type-mismatch.rs
similarity index 74%
rename from tests/crashes/124004.rs
rename to tests/ui/pattern/box-pattern-type-mismatch.rs
index 1fcf078594578..6c98050325638 100644
--- a/tests/crashes/124004.rs
+++ b/tests/ui/pattern/box-pattern-type-mismatch.rs
@@ -1,10 +1,11 @@
-//@ known-bug: #124004
+//! This test used to ICE #124004
 
 #![feature(box_patterns)]
 
 use std::ops::{ Deref };
 
 struct X(dyn Iterator<Item = &'a ()>);
+//~^ ERROR: use of undeclared lifetime name `'a`
 
 impl Deref for X {
     type Target = isize;
diff --git a/tests/ui/pattern/box-pattern-type-mismatch.stderr b/tests/ui/pattern/box-pattern-type-mismatch.stderr
new file mode 100644
index 0000000000000..14f7dbbd839c0
--- /dev/null
+++ b/tests/ui/pattern/box-pattern-type-mismatch.stderr
@@ -0,0 +1,19 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/box-pattern-type-mismatch.rs:7:31
+   |
+LL | struct X(dyn Iterator<Item = &'a ()>);
+   |                               ^^ undeclared lifetime
+   |
+   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
+help: consider making the bound lifetime-generic with a new `'a` lifetime
+   |
+LL | struct X(dyn for<'a> Iterator<Item = &'a ()>);
+   |              +++++++
+help: consider introducing lifetime `'a` here
+   |
+LL | struct X<'a>(dyn Iterator<Item = &'a ()>);
+   |         ++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0261`.
diff --git a/tests/ui/pattern/missing_lifetime.rs b/tests/ui/pattern/missing_lifetime.rs
new file mode 100644
index 0000000000000..081f667d8f6a9
--- /dev/null
+++ b/tests/ui/pattern/missing_lifetime.rs
@@ -0,0 +1,25 @@
+//! This test used to ICE: rust-lang/rust#125914
+//! Instead of actually analyzing the erroneous patterns,
+//! we instead stop after typeck where errors are already
+//! reported.
+
+enum AstKind<'ast> {
+    //~^ ERROR: `'ast` is never used
+    ExprInt,
+}
+
+enum Foo {
+    Bar(isize),
+    Baz,
+}
+
+enum Other {
+    Other1(Foo),
+    Other2(AstKind), //~ ERROR: missing lifetime specifier
+}
+
+fn main() {
+    match Other::Other1(Foo::Baz) {
+        ::Other::Other2(::Foo::Bar(..)) => {}
+    }
+}
diff --git a/tests/ui/pattern/missing_lifetime.stderr b/tests/ui/pattern/missing_lifetime.stderr
new file mode 100644
index 0000000000000..ec4063fd289ad
--- /dev/null
+++ b/tests/ui/pattern/missing_lifetime.stderr
@@ -0,0 +1,25 @@
+error[E0106]: missing lifetime specifier
+  --> $DIR/missing_lifetime.rs:18:12
+   |
+LL |     Other2(AstKind),
+   |            ^^^^^^^ expected named lifetime parameter
+   |
+help: consider introducing a named lifetime parameter
+   |
+LL ~ enum Other<'a> {
+LL |     Other1(Foo),
+LL ~     Other2(AstKind<'a>),
+   |
+
+error[E0392]: lifetime parameter `'ast` is never used
+  --> $DIR/missing_lifetime.rs:6:14
+   |
+LL | enum AstKind<'ast> {
+   |              ^^^^ unused lifetime parameter
+   |
+   = help: consider removing `'ast`, referring to it in a field, or using a marker such as `PhantomData`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0106, E0392.
+For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/pattern/type_mismatch.rs b/tests/ui/pattern/type_mismatch.rs
new file mode 100644
index 0000000000000..408ff75884712
--- /dev/null
+++ b/tests/ui/pattern/type_mismatch.rs
@@ -0,0 +1,30 @@
+//! This test used to ICE: rust-lang/rust#109812
+//! Instead of actually analyzing the erroneous patterns,
+//! we instead stop after typeck where errors are already
+//! reported.
+
+#![warn(rust_2021_incompatible_closure_captures)]
+
+enum Either {
+    One(X),
+    Two(X),
+}
+
+struct X(Y);
+
+struct Y;
+
+fn consume_fnmut(_: impl FnMut()) {}
+
+fn move_into_fnmut() {
+    let x = X(Y);
+
+    consume_fnmut(|| {
+        let Either::Two(ref mut _t) = x;
+        //~^ ERROR: mismatched types
+
+        let X(mut _t) = x;
+    });
+}
+
+fn main() {}
diff --git a/tests/ui/pattern/type_mismatch.stderr b/tests/ui/pattern/type_mismatch.stderr
new file mode 100644
index 0000000000000..b0441b1fadcfe
--- /dev/null
+++ b/tests/ui/pattern/type_mismatch.stderr
@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+  --> $DIR/type_mismatch.rs:23:13
+   |
+LL |         let Either::Two(ref mut _t) = x;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^   - this expression has type `X`
+   |             |
+   |             expected `X`, found `Either`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution.current.stderr b/tests/ui/type-alias-impl-trait/method_resolution.current.stderr
new file mode 100644
index 0000000000000..a9c05ad33424d
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution.current.stderr
@@ -0,0 +1,15 @@
+error[E0599]: no method named `bar` found for struct `Bar<u32>` in the current scope
+  --> $DIR/method_resolution.rs:21:14
+   |
+LL | struct Bar<T>(T);
+   | ------------- method `bar` not found for this struct
+...
+LL |         self.bar()
+   |              ^^^ method not found in `Bar<u32>`
+   |
+   = note: the method was found for
+           - `Bar<Foo>`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution.next.stderr b/tests/ui/type-alias-impl-trait/method_resolution.next.stderr
new file mode 100644
index 0000000000000..6b34358a56ea3
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution.next.stderr
@@ -0,0 +1,12 @@
+error[E0599]: no method named `bar` found for struct `Bar<u32>` in the current scope
+  --> $DIR/method_resolution.rs:21:14
+   |
+LL | struct Bar<T>(T);
+   | ------------- method `bar` not found for this struct
+...
+LL |         self.bar()
+   |              ^^^ method cannot be called on `Bar<u32>` due to unsatisfied trait bounds
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution.rs b/tests/ui/type-alias-impl-trait/method_resolution.rs
new file mode 100644
index 0000000000000..f636aba15c0c4
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution.rs
@@ -0,0 +1,30 @@
+//! `Bar<u32>::foo` is not defining `Foo`, so it cannot rely on the fact that
+//! `u32` is the hidden type of `Foo` to call `bar`
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+#![feature(type_alias_impl_trait)]
+
+type Foo = impl Sized;
+
+struct Bar<T>(T);
+
+impl Bar<Foo> {
+    fn bar(mut self) {
+        self.0 = 42_u32;
+    }
+}
+
+impl Bar<u32> {
+    fn foo(self) {
+        self.bar()
+        //~^ ERROR: no method named `bar`
+    }
+}
+
+fn foo() -> Foo {
+    42_u32
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/method_resolution2.rs b/tests/ui/type-alias-impl-trait/method_resolution2.rs
new file mode 100644
index 0000000000000..f69661db79922
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution2.rs
@@ -0,0 +1,28 @@
+//! Check that we do unify `Bar<Foo>` with `Bar<u32>`, as the
+//! `foo` method call can be resolved unambiguously by doing so.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(type_alias_impl_trait)]
+
+type Foo = impl Sized;
+
+struct Bar<T>(T);
+
+impl Bar<Foo> {
+    fn bar(self) {
+        self.foo()
+    }
+}
+
+impl Bar<u32> {
+    fn foo(self) {}
+}
+
+fn foo() -> Foo {
+    42_u32
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/method_resolution3.current.stderr b/tests/ui/type-alias-impl-trait/method_resolution3.current.stderr
new file mode 100644
index 0000000000000..e992d059daf7d
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution3.current.stderr
@@ -0,0 +1,21 @@
+error[E0307]: invalid `self` parameter type: `Bar<u32>`
+  --> $DIR/method_resolution3.rs:16:18
+   |
+LL |     fn bar(self: Bar<u32>) {
+   |                  ^^^^^^^^
+   |
+   = note: type of `self` must be `Self` or a type that dereferences to it
+   = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
+
+error[E0307]: invalid `self` parameter type: `&Bar<u32>`
+  --> $DIR/method_resolution3.rs:21:18
+   |
+LL |     fn baz(self: &Bar<u32>) {
+   |                  ^^^^^^^^^
+   |
+   = note: type of `self` must be `Self` or a type that dereferences to it
+   = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0307`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution3.next.stderr b/tests/ui/type-alias-impl-trait/method_resolution3.next.stderr
new file mode 100644
index 0000000000000..9272017cdf5d1
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution3.next.stderr
@@ -0,0 +1,15 @@
+error[E0271]: type mismatch resolving `Foo == u32`
+  --> $DIR/method_resolution3.rs:16:18
+   |
+LL |     fn bar(self: Bar<u32>) {
+   |                  ^^^^^^^^ types differ
+
+error[E0271]: type mismatch resolving `Foo == u32`
+  --> $DIR/method_resolution3.rs:21:18
+   |
+LL |     fn baz(self: &Bar<u32>) {
+   |                  ^^^^^^^^^ types differ
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0271`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution3.rs b/tests/ui/type-alias-impl-trait/method_resolution3.rs
new file mode 100644
index 0000000000000..447f3144b822c
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution3.rs
@@ -0,0 +1,36 @@
+//! Check that one cannot use arbitrary self types where a generic parameter
+//! mismatches with an opaque type. In theory this could unify with the opaque
+//! type, registering the generic parameter as the hidden type of the opaque type.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+#![feature(type_alias_impl_trait, arbitrary_self_types)]
+
+type Foo = impl Copy;
+
+#[derive(Copy, Clone)]
+struct Bar<T>(T);
+
+impl Bar<Foo> {
+    fn bar(self: Bar<u32>) {
+        //[current]~^ ERROR: invalid `self` parameter
+        //[next]~^^ ERROR: type mismatch resolving `Foo == u32`
+        self.foo()
+    }
+    fn baz(self: &Bar<u32>) {
+        //[current]~^ ERROR: invalid `self` parameter
+        //[next]~^^ ERROR: type mismatch resolving `Foo == u32`
+        self.foo()
+    }
+}
+
+impl Bar<u32> {
+    fn foo(self) {}
+}
+
+fn foo() -> Foo {
+    42_u32
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/method_resolution4.current.stderr b/tests/ui/type-alias-impl-trait/method_resolution4.current.stderr
new file mode 100644
index 0000000000000..3a2ca18f89097
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution4.current.stderr
@@ -0,0 +1,21 @@
+error[E0307]: invalid `self` parameter type: `Bar<Foo>`
+  --> $DIR/method_resolution4.rs:27:18
+   |
+LL |     fn foo(self: Bar<Foo>) {
+   |                  ^^^^^^^^
+   |
+   = note: type of `self` must be `Self` or a type that dereferences to it
+   = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
+
+error[E0307]: invalid `self` parameter type: `&Bar<Foo>`
+  --> $DIR/method_resolution4.rs:32:20
+   |
+LL |     fn foomp(self: &Bar<Foo>) {
+   |                    ^^^^^^^^^
+   |
+   = note: type of `self` must be `Self` or a type that dereferences to it
+   = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0307`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution4.next.stderr b/tests/ui/type-alias-impl-trait/method_resolution4.next.stderr
new file mode 100644
index 0000000000000..33ed2800ebe0c
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution4.next.stderr
@@ -0,0 +1,15 @@
+error[E0271]: type mismatch resolving `u32 == Foo`
+  --> $DIR/method_resolution4.rs:27:18
+   |
+LL |     fn foo(self: Bar<Foo>) {
+   |                  ^^^^^^^^ types differ
+
+error[E0271]: type mismatch resolving `u32 == Foo`
+  --> $DIR/method_resolution4.rs:32:20
+   |
+LL |     fn foomp(self: &Bar<Foo>) {
+   |                    ^^^^^^^^^ types differ
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0271`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution4.rs b/tests/ui/type-alias-impl-trait/method_resolution4.rs
new file mode 100644
index 0000000000000..42ed04b3c30f6
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution4.rs
@@ -0,0 +1,39 @@
+//! Check that one cannot use arbitrary self types where a generic parameter
+//! mismatches with an opaque type. In theory this could unify with the opaque
+//! type, registering the generic parameter as the hidden type of the opaque type.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+#![feature(type_alias_impl_trait, arbitrary_self_types)]
+
+mod foo {
+    pub type Foo = impl Copy;
+
+    fn foo() -> Foo {
+        42_u32
+    }
+}
+use foo::Foo;
+
+#[derive(Copy, Clone)]
+struct Bar<T>(T);
+
+impl Bar<Foo> {
+    fn bar(self) {}
+}
+
+impl Bar<u32> {
+    fn foo(self: Bar<Foo>) {
+        //[current]~^ ERROR: invalid `self` parameter
+        //[next]~^^ ERROR: type mismatch resolving `u32 == Foo`
+        self.bar()
+    }
+    fn foomp(self: &Bar<Foo>) {
+        //[current]~^ ERROR: invalid `self` parameter
+        //[next]~^^ ERROR: type mismatch resolving `u32 == Foo`
+        self.bar()
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/method_resolution5.rs b/tests/ui/type-alias-impl-trait/method_resolution5.rs
new file mode 100644
index 0000000000000..64355e4560de2
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution5.rs
@@ -0,0 +1,33 @@
+//! Even though `Bar<u32>::foo` is defining `Foo`, the old solver does
+//! not figure out that `u32` is the hidden type of `Foo` to call `bar`.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(type_alias_impl_trait)]
+
+type Foo = impl Sized;
+
+struct Bar<T>(T);
+
+impl Bar<Foo> {
+    fn bar(mut self) {
+        self.0 = 42_u32;
+    }
+}
+
+impl Bar<u32> {
+    fn foo(self)
+    where
+        Foo:,
+    {
+        self.bar()
+    }
+}
+
+fn foo() -> Foo {
+    42_u32
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.current.stderr b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.current.stderr
new file mode 100644
index 0000000000000..f331da1af8793
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.current.stderr
@@ -0,0 +1,15 @@
+error: item does not constrain `Tait::{opaque#0}`, but has it in its signature
+  --> $DIR/method_resolution_trait_method_from_opaque.rs:24:8
+   |
+LL |     fn foo(&mut self) {
+   |        ^^^
+   |
+   = note: consider moving the opaque type's declaration and defining uses into a separate module
+note: this opaque type is in the signature
+  --> $DIR/method_resolution_trait_method_from_opaque.rs:17:13
+   |
+LL | type Tait = impl Iterator<Item = ()>;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.next.stderr b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.next.stderr
new file mode 100644
index 0000000000000..2617ce124c105
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.next.stderr
@@ -0,0 +1,9 @@
+error[E0282]: type annotations needed
+  --> $DIR/method_resolution_trait_method_from_opaque.rs:26:9
+   |
+LL |         self.bar.next().unwrap();
+   |         ^^^^^^^^ cannot infer type
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.rs b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.rs
new file mode 100644
index 0000000000000..b6adf08853f2f
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/method_resolution_trait_method_from_opaque.rs
@@ -0,0 +1,31 @@
+//! This test demonstrates how method calls will attempt to unify an opaque type with a reference
+//! if the method takes `&self` as its argument. This is almost never what is desired, as the user
+//! would like to have method resolution happen on the opaque type instead of inferring the hidden
+//! type. Once type-alias-impl-trait requires annotating which functions should constrain the hidden
+//! type, this won't be as much of a problem, as most functions that do method calls on opaque types
+//! won't also be the ones defining the hidden type.
+
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+
+#![feature(type_alias_impl_trait)]
+
+pub struct Foo {
+    bar: Tait,
+}
+
+type Tait = impl Iterator<Item = ()>;
+
+impl Foo {
+    pub fn new() -> Foo {
+        Foo { bar: std::iter::empty() }
+    }
+
+    fn foo(&mut self) {
+        //[current]~^ ERROR: item does not constrain
+        self.bar.next().unwrap();
+        //[next]~^ ERROR: type annotations needed
+    }
+}
+
+fn main() {}