ref: 7f952c8f7f08adf3242fe8a3ef2300772a6099b6
dir: /tests/StandDer.hs/
module StandDer where data X = X deriving instance Show X data T a = A | B | C a | D (T a) deriving instance (Show a) => Show (T a) main :: IO () main = do print X print [A, B, C True, D A]