import CmdLineOpts ( opt_UnboxStrictFields )
import Maybe
import ListSetOps ( assoc )
-import Util ( zipEqual, zipWithEqual, equalLength )
+import Util ( zipEqual, zipWithEqual, equalLength, notNull )
\end{code}
isUnboxedTupleCon (MkData {dcTyCon = tc}) = isUnboxedTupleTyCon tc
isExistentialDataCon :: DataCon -> Bool
-isExistentialDataCon (MkData {dcExTyVars = tvs}) = not (null tvs)
+isExistentialDataCon (MkData {dcExTyVars = tvs}) = notNull tvs
\end{code}