GHC 3.02 doesn't have Maybe.isNothing; switch to using isJust instead.
maybe_unpack_fields :: UniqSet TyCon -> [(Type,StrictnessMark)] -> Maybe [Type]
maybe_unpack_fields set tys
- | any isNothing unpacked_fields = Nothing
- | otherwise = Just (concat (catMaybes unpacked_fields))
+ | all isJust unpacked_fields = Just (concat (catMaybes unpacked_fields))
+ | otherwise = Nothing
where unpacked_fields = map (\(ty,str) -> maybe_unpack_field set ty str) tys
\end{code}