Don't rebind in transitive_bounds_that_define_assoc_type

Author: jackh726

compiler/rustc_infer/src/traits/util.rs

@@ -305,9 +305,7 @@ pub fn transitive_bounds_that_define_assoc_type<'tcx>(
                     Some(assoc_name),
                 ));
                 for (super_predicate, _) in super_predicates.predicates {
-                    let bound_predicate = super_predicate.kind();
-                    let subst_predicate = super_predicate
-                        .subst_supertrait(tcx, &bound_predicate.rebind(trait_ref.skip_binder()));
+                    let subst_predicate = super_predicate.subst_supertrait(tcx, &trait_ref);
                     if let Some(binder) = subst_predicate.to_opt_poly_trait_ref() {
                         stack.push(binder.value);
                     }