shrinkDataType :: Declaration -> [Declaration]
shrinkDataType (Data name params cases)
    | length cases > 1 = (Data name params . return) <$> cases
    | otherwise        = []
shrinkDataType :: Declaration -> [Declaration]
shrinkDataType (Data name params cases)
    | length cases > 1 = (Data name params . return) <$> cases
    | otherwise        = []
shrinkDataType (Data name params cases)
    | length cases > 1 = (Data name params . return) <$> cases
    | otherwise        = []