Merging upstream version 1.71.1+dfsg1.

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

1 files changed, 8 insertions, 4 deletions

diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs
index ef01d5d51..74a78f380 100644
--- a/compiler/rustc_infer/src/traits/util.rs
+++ b/compiler/rustc_infer/src/traits/util.rs
@@ -200,6 +200,10 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> {
         let bound_predicate = elaboratable.predicate().kind();
         match bound_predicate.skip_binder() {
             ty::PredicateKind::Clause(ty::Clause::Trait(data)) => {
+                // Negative trait bounds do not imply any supertrait bounds
+                if data.polarity == ty::ImplPolarity::Negative {
+                    return;
+                }
                 // Get predicates implied by the trait, or only super predicates if we only care about self predicates.
                 let predicates = if self.only_self {
                     tcx.super_predicates_of(data.def_id())
@@ -376,11 +380,11 @@ pub fn transitive_bounds<'tcx>(
 }
 
 /// A specialized variant of `elaborate` that only elaborates trait references that may
-/// define the given associated type `assoc_name`. It uses the
-/// `super_predicates_that_define_assoc_type` query to avoid enumerating super-predicates that
+/// define the given associated item with the name `assoc_name`. It uses the
+/// `super_predicates_that_define_assoc_item` query to avoid enumerating super-predicates that
 /// aren't related to `assoc_item`. This is used when resolving types like `Self::Item` or
 /// `T::Item` and helps to avoid cycle errors (see e.g. #35237).
-pub fn transitive_bounds_that_define_assoc_type<'tcx>(
+pub fn transitive_bounds_that_define_assoc_item<'tcx>(
     tcx: TyCtxt<'tcx>,
     bounds: impl Iterator<Item = ty::PolyTraitRef<'tcx>>,
     assoc_name: Ident,
@@ -393,7 +397,7 @@ pub fn transitive_bounds_that_define_assoc_type<'tcx>(
             let anon_trait_ref = tcx.anonymize_bound_vars(trait_ref);
             if visited.insert(anon_trait_ref) {
                 let super_predicates =
-                    tcx.super_predicates_that_define_assoc_type((trait_ref.def_id(), assoc_name));
+                    tcx.super_predicates_that_define_assoc_item((trait_ref.def_id(), assoc_name));
                 for (super_predicate, _) in super_predicates.predicates {
                     let subst_predicate = super_predicate.subst_supertrait(tcx, &trait_ref);
                     if let Some(binder) = subst_predicate.to_opt_poly_trait_pred() {