diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
index b20636174eeac..62d5e50dbc548 100644
--- a/compiler/rustc_trait_selection/src/traits/engine.rs
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -158,7 +158,7 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
         self.infcx
             .at(cause, param_env)
             .define_opaque_types(true)
-            .sup(expected, actual)
+            .sub(expected, actual)
             .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
     }