+ -- defer splitting by generating an equality constraint
+ defer = do { ([ty1, ty2], coi) <- boxySplitDefer arg_kinds mk_res_ty orig_ty
+ ; return ((ty1, ty2), coi)
+ }
+ where
+ orig_kind = typeKind orig_ty
+ arg_kinds = [mkArrowKind liftedTypeKind (defaultKind orig_kind),
+ -- m :: * -> k
+ liftedTypeKind] -- arg type :: *
+
+ -- build type application
+ mk_res_ty [fun_ty', arg_ty'] = mkAppTy fun_ty' arg_ty'
+ mk_res_ty _other = panic "TcUnify.mk_res_ty2"
+