Prefer object candidates over impl candidates in new selection

2023-07-06 04:48:33 +00:00
parent bd8aabef31
commit 3acaa568c2
2 changed files with 21 additions and 0 deletions
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
@@ -173,10 +173,18 @@ fn candidate_should_be_dropped_in_favor_of<'tcx>(
            victim_idx >= other_idx
        }
        (_, CandidateSource::ParamEnv(_)) => true,
+
+        (
+            CandidateSource::BuiltinImpl(BuiltinImplSource::Object),
+            CandidateSource::BuiltinImpl(BuiltinImplSource::Object),
+        ) => false,
+        (_, CandidateSource::BuiltinImpl(BuiltinImplSource::Object)) => true,
+
        (CandidateSource::Impl(victim_def_id), CandidateSource::Impl(other_def_id)) => {
            tcx.specializes((other_def_id, victim_def_id))
                && other.result.value.certainty == Certainty::Yes
        }
+
        _ => false,
    }
 }