T7524.hs:5:15: error:
    Conflicting family instance declarations:
      forall {k2} {a :: k2}. F a a = Int -- Defined at T7524.hs:5:15
      forall {k1} {k2} {a :: k1} {b :: k2}.
        F a b = Bool -- Defined at T7524.hs:6:15