T10403.hs:16:7: warning: [-Wpartial-type-signatures (in -Wdefault)]
    • Found extra-constraints wildcard standing for ‘Functor f’
      Where: ‘f’ is a rigid type variable bound by
               the inferred type of h1 :: Functor f => (a -> a1) -> f a -> H f
               at T10403.hs:18:1-41
    • In the type signature: h1 :: _ => _

T10403.hs:16:12: warning: [-Wpartial-type-signatures (in -Wdefault)]
    • Found type wildcard ‘_’ standing for ‘(a -> a1) -> f a -> H f’
      Where: ‘a1’, ‘a’, ‘f’ are rigid type variables bound by
               the inferred type of h1 :: Functor f => (a -> a1) -> f a -> H f
               at T10403.hs:18:1-41
    • In the type signature: h1 :: _ => _

T10403.hs:20:7: warning: [-Wpartial-type-signatures (in -Wdefault)]
    • Found type wildcard ‘_’
        standing for ‘(a -> a1) -> B t0 a -> H (B t0)’
      Where: ‘t0’ is an ambiguous type variable
             ‘a1’, ‘a’ are rigid type variables bound by
               the inferred type of h2 :: (a -> a1) -> B t0 a -> H (B t0)
               at T10403.hs:23:1-41
    • In the type signature: h2 :: _

T10403.hs:29:8: warning: [-Wdeferred-type-errors (in -Wdefault)]
    • Couldn't match type ‘t0’ with ‘t’
      Expected: H (B t)
        Actual: H (B t0)
        because type variable ‘t’ would escape its scope
      This (rigid, skolem) type variable is bound by
        the type signature for:
          app2 :: forall t. H (B t)
        at T10403.hs:28:1-15
    • In the expression: h2 (H . I) (B ())
      In an equation for ‘app2’: app2 = h2 (H . I) (B ())
    • Relevant bindings include
        app2 :: H (B t) (bound at T10403.hs:29:1)