T16326_Fail4.hs:6:30: error:
    • Illegal visible, dependent quantification in the type of a term:
        forall a1 -> Maybe a1 -> Maybe a1 -> Maybe a1
      (GHC does not yet support this)
    • In an expression type signature:
        forall a -> Maybe a -> Maybe a -> Maybe a
      In the first argument of ‘zipWith’, namely
        ‘((<>) :: forall a -> Maybe a -> Maybe a -> Maybe a)’
      In the expression:
        zipWith ((<>) :: forall a -> Maybe a -> Maybe a -> Maybe a) xs ys