diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index a80fe6a3362b4..1c525fb55e1b5 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -787,7 +787,7 @@ impl<'tcx> ExistentialPredicate<'tcx> {
                 tcx.def_path_hash(a.item_def_id).cmp(&tcx.def_path_hash(b.item_def_id))
             }
             (AutoTrait(ref a), AutoTrait(ref b)) => {
-                tcx.trait_def(*a).def_path_hash.cmp(&tcx.trait_def(*b).def_path_hash)
+                tcx.def_path_hash(*a).cmp(&tcx.def_path_hash(*b))
             }
             (Trait(_), _) => Ordering::Less,
             (Projection(_), Trait(_)) => Ordering::Greater,