T7696.hs:9:6: error: [GHC-18872]
    • Couldn't match kind ‘*’ with ‘* -> *’
      When matching types
        t0 :: (* -> *) -> *
        w :: * -> *
      Expected: ((), w ())
        Actual: (m0 a0, t0 m0)
    • In the expression: f1
      In an equation for ‘f2’: f2 = f1
    • Relevant bindings include
        f2 :: ((), w ()) (bound at T7696.hs:9:1)