{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}

import Prelude hiding (any)

main :: IO ()
main =
  print $
    (\(x :: forall a . Any a => a) ->
        (x :: Int -> Int) (x :: Int))
      any

class Any a where
  any :: a

instance Any Int where
  any = 0

instance Any (a -> a) where
  any = id

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}

import Prelude hiding (any)

main :: IO ()
main =
  print $
    ((\x -> x x) :: (forall a . Any a => a) -> Int)
      any

class Any a where
  any :: a

instance Any Int where
  any = 0

instance a ~ b => Any (a -> b) where
  any = id