T2538.hs:6:6: error:
    • Illegal qualified type: Eq a => a -> a
      Perhaps you intended to use RankNTypes
    • In the type signature:
        f :: (Eq a => a -> a) -> Int

T2538.hs:9:6: error:
    • Illegal qualified type: Eq a => a -> a
      GHC doesn't yet support impredicative polymorphism
    • In the type signature:
        g :: [Eq a => a -> a] -> Int

T2538.hs:12:6: error:
    • Illegal qualified type: Eq a => a -> a
      GHC doesn't yet support impredicative polymorphism
    • In the type signature:
        h :: Ix (Eq a => a -> a) => Int