module Rank2(main) where f :: (forall a . a -> a) -> (Int, Bool) f i = (i (1::Int), i True) g :: (forall a . a -> Int -> a) -> (Int, Bool) g c = (c (1::Int) (1::Int), c True (1::Int)) newtype Id = Id (forall a . a -> a) iD :: Id iD = Id (\ x -> x) main :: IO () main = do print $ f id print $ g const case iD of Id i -> print (i (1::Int), i True)