Rollup of 10 pull requests

compiler/rustc_ast/src/ast.rs

@@ -2126,7 +2126,8 @@ pub struct BareFnTy {
     pub ext: Extern,
     pub generic_params: ThinVec<GenericParam>,
     pub decl: P<FnDecl>,
-    /// Span of the `fn(...) -> ...` part.
+    /// Span of the `[unsafe] [extern] fn(...) -> ...` part, i.e. everything
+    /// after the generic params (if there are any, e.g. `for<'a>`).
     pub decl_span: Span,
 }
 

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -464,7 +464,7 @@ impl<'a> AstValidator<'a> {
                 {
                     self.dcx().emit_err(errors::InvalidSafetyOnExtern {
                         item_span: span,
-                        block: self.current_extern_span(),
+                        block: self.current_extern_span().shrink_to_lo(),
                     });
                 }
             }

compiler/rustc_ast_passes/src/errors.rs

@@ -221,7 +221,7 @@ pub enum ExternBlockSuggestion {
 pub struct InvalidSafetyOnExtern {
     #[primary_span]
     pub item_span: Span,
-    #[suggestion(code = "", applicability = "maybe-incorrect")]
+    #[suggestion(code = "unsafe ", applicability = "machine-applicable", style = "verbose")]
     pub block: Span,
 }
 

compiler/rustc_hir_analysis/src/check/compare_impl_item/refine.rs

@@ -171,10 +171,10 @@ pub(super) fn check_refining_return_position_impl_trait_in_trait<'tcx>(
     }
     // Resolve any lifetime variables that may have been introduced during normalization.
     let Ok((trait_bounds, impl_bounds)) = infcx.fully_resolve((trait_bounds, impl_bounds)) else {
-        // This code path is not reached in any tests, but may be reachable. If
-        // this is triggered, it should be converted to `delayed_bug` and the
-        // triggering case turned into a test.
-        tcx.dcx().bug("encountered errors when checking RPITIT refinement (resolution)");
+        // If resolution didn't fully complete, we cannot continue checking RPITIT refinement, and
+        // delay a bug as the original code contains load-bearing errors.
+        tcx.dcx().delayed_bug("encountered errors when checking RPITIT refinement (resolution)");
+        return;
     };
 
     // For quicker lookup, use an `IndexSet` (we don't use one earlier because

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -2831,69 +2831,119 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         errors: Vec<FulfillmentError<'tcx>>,
         suggest_derive: bool,
     ) {
-        let all_local_types_needing_impls =
-            errors.iter().all(|e| match e.obligation.predicate.kind().skip_binder() {
+        let preds: Vec<_> = errors
+            .iter()
+            .filter_map(|e| match e.obligation.predicate.kind().skip_binder() {
                 ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) => {
                     match pred.self_ty().kind() {
-                        ty::Adt(def, _) => def.did().is_local(),
-                        _ => false,
+                        ty::Adt(_, _) => Some(pred),
+                        _ => None,
                     }
                 }
-                _ => false,
-            });
-        let mut preds: Vec<_> = errors
-            .iter()
-            .filter_map(|e| match e.obligation.predicate.kind().skip_binder() {
-                ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) => Some(pred),
                 _ => None,
             })
             .collect();
-        preds.sort_by_key(|pred| pred.trait_ref.to_string());
-        let def_ids = preds
+
+        // Note for local items and foreign items respectively.
+        let (mut local_preds, mut foreign_preds): (Vec<_>, Vec<_>) =
+            preds.iter().partition(|&pred| {
+                if let ty::Adt(def, _) = pred.self_ty().kind() {
+                    def.did().is_local()
+                } else {
+                    false
+                }
+            });
+
+        local_preds.sort_by_key(|pred: &&ty::TraitPredicate<'_>| pred.trait_ref.to_string());
+        let local_def_ids = local_preds
             .iter()
             .filter_map(|pred| match pred.self_ty().kind() {
                 ty::Adt(def, _) => Some(def.did()),
                 _ => None,
             })
             .collect::<FxIndexSet<_>>();
-        let mut spans: MultiSpan = def_ids
+        let mut local_spans: MultiSpan = local_def_ids
             .iter()
             .filter_map(|def_id| {
                 let span = self.tcx.def_span(*def_id);
                 if span.is_dummy() { None } else { Some(span) }
             })
             .collect::<Vec<_>>()
             .into();
-
-        for pred in &preds {
+        for pred in &local_preds {
             match pred.self_ty().kind() {
-                ty::Adt(def, _) if def.did().is_local() => {
-                    spans.push_span_label(
+                ty::Adt(def, _) => {
+                    local_spans.push_span_label(
                         self.tcx.def_span(def.did()),
                         format!("must implement `{}`", pred.trait_ref.print_trait_sugared()),
                     );
                 }
                 _ => {}
             }
         }
-
-        if all_local_types_needing_impls && spans.primary_span().is_some() {
-            let msg = if preds.len() == 1 {
+        if local_spans.primary_span().is_some() {
+            let msg = if local_preds.len() == 1 {
                 format!(
                     "an implementation of `{}` might be missing for `{}`",
-                    preds[0].trait_ref.print_trait_sugared(),
-                    preds[0].self_ty()
+                    local_preds[0].trait_ref.print_trait_sugared(),
+                    local_preds[0].self_ty()
                 )
             } else {
                 format!(
                     "the following type{} would have to `impl` {} required trait{} for this \
                      operation to be valid",
-                    pluralize!(def_ids.len()),
-                    if def_ids.len() == 1 { "its" } else { "their" },
-                    pluralize!(preds.len()),
+                    pluralize!(local_def_ids.len()),
+                    if local_def_ids.len() == 1 { "its" } else { "their" },
+                    pluralize!(local_preds.len()),
+                )
+            };
+            err.span_note(local_spans, msg);
+        }
+
+        foreign_preds.sort_by_key(|pred: &&ty::TraitPredicate<'_>| pred.trait_ref.to_string());
+        let foreign_def_ids = foreign_preds
+            .iter()
+            .filter_map(|pred| match pred.self_ty().kind() {
+                ty::Adt(def, _) => Some(def.did()),
+                _ => None,
+            })
+            .collect::<FxIndexSet<_>>();
+        let mut foreign_spans: MultiSpan = foreign_def_ids
+            .iter()
+            .filter_map(|def_id| {
+                let span = self.tcx.def_span(*def_id);
+                if span.is_dummy() { None } else { Some(span) }
+            })
+            .collect::<Vec<_>>()
+            .into();
+        for pred in &foreign_preds {
+            match pred.self_ty().kind() {
+                ty::Adt(def, _) => {
+                    foreign_spans.push_span_label(
+                        self.tcx.def_span(def.did()),
+                        format!("not implement `{}`", pred.trait_ref.print_trait_sugared()),
+                    );
+                }
+                _ => {}
+            }
+        }
+        if foreign_spans.primary_span().is_some() {
+            let msg = if foreign_preds.len() == 1 {
+                format!(
+                    "the foreign item type `{}` doesn't implement `{}`",
+                    foreign_preds[0].self_ty(),
+                    foreign_preds[0].trait_ref.print_trait_sugared()
+                )
+            } else {
+                format!(
+                    "the foreign item type{} {} implement required trait{} for this \
+                     operation to be valid",
+                    pluralize!(foreign_def_ids.len()),
+                    if foreign_def_ids.len() > 1 { "don't" } else { "doesn't" },
+                    pluralize!(foreign_preds.len()),
                 )
             };
-            err.span_note(spans, msg);
+            err.span_note(foreign_spans, msg);
         }
 
         let preds: Vec<_> = errors

compiler/rustc_next_trait_solver/src/solve/alias_relate.rs

@@ -32,14 +32,14 @@ where
         &mut self,
         goal: Goal<I, (I::Term, I::Term, ty::AliasRelationDirection)>,
     ) -> QueryResult<I> {
-        let tcx = self.cx();
+        let cx = self.cx();
         let Goal { param_env, predicate: (lhs, rhs, direction) } = goal;
         debug_assert!(lhs.to_alias_term().is_some() || rhs.to_alias_term().is_some());
 
         // Structurally normalize the lhs.
         let lhs = if let Some(alias) = lhs.to_alias_term() {
             let term = self.next_term_infer_of_kind(lhs);
-            self.add_normalizes_to_goal(goal.with(tcx, ty::NormalizesTo { alias, term }));
+            self.add_normalizes_to_goal(goal.with(cx, ty::NormalizesTo { alias, term }));
             term
         } else {
             lhs
@@ -48,7 +48,7 @@ where
         // Structurally normalize the rhs.
         let rhs = if let Some(alias) = rhs.to_alias_term() {
             let term = self.next_term_infer_of_kind(rhs);
-            self.add_normalizes_to_goal(goal.with(tcx, ty::NormalizesTo { alias, term }));
+            self.add_normalizes_to_goal(goal.with(cx, ty::NormalizesTo { alias, term }));
             term
         } else {
             rhs