{-# RULES
"map/map" [2]
    map
        f
        (map g xs) =
        map
            (f . g)
            xs
    #-}

{-# RULES
"map/map" [1] forall x y z.
    map
        f
        (map g xs) =
        map
            (f . g)
            xs
    #-}

{-# RULES
"++" [~1] forall xs ys. xs ++ ys = augment (\c n -> foldr c n xs) ys
    #-}