isClassPred, isEqPred, isIPPred :: PredType -> Bool
isClassPred ty = case tyConAppTyCon_maybe ty of
    Just tyCon | isClassTyCon tyCon -> True
    _                               -> False
isClassPred, isEqPred, isIPPred :: PredType -> Bool
isClassPred ty = case tyConAppTyCon_maybe ty of
    Just tyCon | isClassTyCon tyCon -> True
    _                               -> False
isClassPred ty = case tyConAppTyCon_maybe ty of
    Just tyCon | isClassTyCon tyCon -> True
    _                               -> False