Fix perf issue for auto trait selection

2022-03-26 14:58:19 +01:00
parent 3fe3b89cd5
commit ad88732254
3 changed files with 29 additions and 2 deletions
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -94,6 +94,24 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                trait_pred.to_poly_trait_predicate(),
            ));

+            match result {
+                Ok(Some(ImplSource::UserDefined(_))) => {
+                    debug!(
+                        "find_auto_trait_generics({:?}): \
+                         manual impl found, bailing out",
+                        trait_ref
+                    );
+                    return true;
+                }
+                _ => {}
+            }
+
+            let result = selcx.select(&Obligation::new(
+                ObligationCause::dummy(),
+                orig_env,
+                trait_pred.to_poly_trait_predicate_negative_polarity(),
+            ));
+
            match result {
                Ok(Some(ImplSource::UserDefined(_))) => {
                    debug!(