T14325.hs:11:9: error: [GHC-25897]
    • Couldn't match type ‘b’ with ‘f b’
        arising from a superclass required to satisfy ‘C b (f b)’,
        arising from a use of ‘foo’
      ‘b’ is a rigid type variable bound by
        the type signature for:
          hm3 :: forall (f :: * -> *) b. C (f b) b => b -> f b
        at T14325.hs:10:1-28
    • In the expression: foo x
      In an equation for ‘hm3’: hm3 x = foo x
    • Relevant bindings include
        x :: b (bound at T14325.hs:11:5)
        hm3 :: b -> f b (bound at T14325.hs:11:1)