--IO/State1 ability
ability IO where
  launchMissiles : {IO} ()
ability State se2 where
  put : ∀ se . se -> {State se} ()
  get : ∀ se . () -> {State se} se
foo : () -> {IO} ()
foo unit =
-- inner binding can't access outer abilities unless it declares
-- them explicitly
  incBy : Int -> {State Int} ()
  incBy i =
    launchMissiles -- not allowed
    y = State.get()
    State.put (y Int.+ i)
  ()
()