SimpleFail5a.hs:31:11: error:
    • Couldn't match type ‘a’ with ‘Int’
      Expected: S3 a
        Actual: S3 Int
      ‘a’ is a rigid type variable bound by
        the type signature for:
          bar3wrong :: forall a. S3 a -> a
        at SimpleFail5a.hs:30:1-22
    • In the pattern: D3Int
      In an equation for ‘bar3wrong’: bar3wrong D3Int = 1
    • Relevant bindings include
        bar3wrong :: S3 a -> a (bound at SimpleFail5a.hs:31:1)