tyConSingleAlgDataCon_maybe :: TyCon -> Maybe DataCon
-- Returns (Just con) for single-constructor *algebraic* data types
-- *not* newtypes
tyConSingleAlgDataCon_maybe (TupleTyCon {dataCon = c})
    = Just c
tyConSingleAlgDataCon_maybe :: TyCon -> Maybe DataCon
tyConSingleAlgDataCon_maybe (TupleTyCon {dataCon = c})
    = Just c
tyConSingleAlgDataCon_maybe (TupleTyCon {dataCon = c})
    = Just c