tcfail104.hs:16:12: error: [GHC-83865]
    • Couldn't match type: Char -> Char
                     with: forall a. a -> a
      Expected: (forall a. a -> a) -> Char -> Char
        Actual: (Char -> Char) -> Char -> Char
    • In the expression: \ x -> x
      In the expression:
        (if v then (\ (x :: forall a. a -> a) -> x) else (\ x -> x)) id 'c'
      In an equation for ‘f3’:
          f3 v
            = (if v then (\ (x :: forall a. a -> a) -> x) else (\ x -> x))
                id 'c'

tcfail104.hs:22:12: error: [GHC-83865]
    • Couldn't match type: forall a. a -> a
                     with: Char -> Char
      Expected: (Char -> Char) -> Char -> Char
        Actual: (forall a. a -> a) -> Char -> Char
    • In the expression: \ (x :: forall a. a -> a) -> x
      In the expression:
        (if v then (\ x -> x) else (\ (x :: forall a. a -> a) -> x)) id 'c'
      In an equation for ‘f4’:
          f4 v
            = (if v then (\ x -> x) else (\ (x :: forall a. a -> a) -> x))
                id 'c'