Split item bounds and item super predicates

2 files changed, 16 insertions, 18 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index d19c2bd1f60..00d00496947 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1098,8 +1098,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                         ))
                     }
                     ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => {
-                        self.tcx.item_bounds(def_id).instantiate(self.tcx, args).iter().find_map(
-                            |pred| {
+                        self.tcx
+                            .item_super_predicates(def_id)
+                            .instantiate(self.tcx, args)
+                            .iter()
+                            .find_map(|pred| {
                                 if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
                         && Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
                         // args tuple will always be args[1]
@@ -1113,8 +1116,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                                 } else {
                                     None
                                 }
-                            },
-                        )
+                            })
                     }
                     ty::Dynamic(data, _, ty::Dyn) => {
                         data.iter().find_map(|pred| {
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 6460613d7d5..53aadfb8a44 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1617,21 +1617,17 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 _ => return ControlFlow::Continue(()),
             };
 
-            for bound in
-                self.tcx().item_bounds(alias_ty.def_id).instantiate(self.tcx(), alias_ty.args)
-            {
-                // HACK: On subsequent recursions, we only care about bounds that don't
-                // share the same type as `self_ty`. This is because for truly rigid
-                // projections, we will never be able to equate, e.g. `<T as Tr>::A`
-                // with `<<T as Tr>::A as Tr>::A`.
-                if in_parent_alias_type {
-                    match bound.kind().skip_binder() {
-                        ty::ClauseKind::Trait(tr) if tr.self_ty() == self_ty => continue,
-                        ty::ClauseKind::Projection(p) if p.self_ty() == self_ty => continue,
-                        _ => {}
-                    }
-                }
+            // HACK: On subsequent recursions, we only care about bounds that don't
+            // share the same type as `self_ty`. This is because for truly rigid
+            // projections, we will never be able to equate, e.g. `<T as Tr>::A`
+            // with `<<T as Tr>::A as Tr>::A`.
+            let relevant_bounds = if in_parent_alias_type {
+                self.tcx().item_non_self_assumptions(alias_ty.def_id)
+            } else {
+                self.tcx().item_super_predicates(alias_ty.def_id)
+            };
 
+            for bound in relevant_bounds.instantiate(self.tcx(), alias_ty.args) {
                 for_each(self, bound, idx)?;
                 idx += 1;
             }