failTc down env = give_up
give_up :: IO a
-give_up = IOERROR (userError "Typecheck failed")
+give_up = ioError (userError "Typecheck failed")
failWithTc :: Message -> TcM a -- Add an error message and fail
failWithTc err_msg = failWithTcM (emptyTidyEnv, err_msg)