New upstream version 1.68.2+dfsg1

[rustc.git] / compiler / rustc_infer / src / infer / equate.rs

diff --git a/compiler/rustc_infer/src/infer/equate.rs b/compiler/rustc_infer/src/infer/equate.rs
index 8682f4d3b7aed970783395d50e8ca09a8b648d64..46e7813d99e562cd1cff9b39b0224eaa75048fb1 100644 (file)
--- a/compiler/rustc_infer/src/infer/equate.rs
+++ b/compiler/rustc_infer/src/infer/equate.rs
@@ -100,11 +100,15 @@ impl<'tcx> TypeRelation<'tcx> for Equate<'_, '_, 'tcx> {
                 self.fields.instantiate(a, RelationDir::EqTo, b_id, self.a_is_expected)?;
             }
 
-            (&ty::Opaque(a_def_id, _), &ty::Opaque(b_def_id, _)) if a_def_id == b_def_id => {
+            (
+                &ty::Alias(ty::Opaque, ty::AliasTy { def_id: a_def_id, .. }),
+                &ty::Alias(ty::Opaque, ty::AliasTy { def_id: b_def_id, .. }),
+            ) if a_def_id == b_def_id => {
                 self.fields.infcx.super_combine_tys(self, a, b)?;
             }
-            (&ty::Opaque(did, ..), _) | (_, &ty::Opaque(did, ..))
-                if self.fields.define_opaque_types && did.is_local() =>
+            (&ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }), _)
+            | (_, &ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }))
+                if self.fields.define_opaque_types && def_id.is_local() =>
             {
                 self.fields.obligations.extend(
                     infcx
@@ -178,6 +182,11 @@ impl<'tcx> TypeRelation<'tcx> for Equate<'_, '_, 'tcx> {
     where
         T: Relate<'tcx>,
     {
+        // A binder is equal to itself if it's structually equal to itself
+        if a == b {
+            return Ok(a);
+        }
+
         if a.skip_binder().has_escaping_bound_vars() || b.skip_binder().has_escaping_bound_vars() {
             self.fields.higher_ranked_sub(a, b, self.a_is_expected)?;
             self.fields.higher_ranked_sub(b, a, self.a_is_expected)?;