diff --git a/compiler/typecheck/TcUnify.lhs b/compiler/typecheck/TcUnify.lhs
index cdeeea0eb1136e32dad243db1f9560a04a402c21..7c2f83d0387587e079cb4a7469a0daa7e94b4d28 100644
--- a/compiler/typecheck/TcUnify.lhs
+++ b/compiler/typecheck/TcUnify.lhs
@@ -235,7 +235,7 @@ matchExpectedTyConApp tc orig_ty
     --    (a::*) ~ Maybe
     -- because that'll make types that are utterly ill-kinded.
     -- This happened in Trac #7368
-    defer = ASSERT2( isLiftedTypeKind res_kind, ppr tc )
+    defer = ASSERT2( isSubOpenTypeKind res_kind, ppr tc )
             do { kappa_tys <- mapM (const newMetaKindVar) kvs
                ; let arg_kinds' = map (substKiWith kvs kappa_tys) arg_kinds
                ; tau_tys <- mapM newFlexiTyVarTy arg_kinds'