box Cacher {
  counter: IntegerBox = 0
  once value: IntegerBox {
    me.counter = me.counter + 1
    return me.counter
  }
}

static box Main {
  main(args) {
    local c = new Cacher()
    print(c.value)   # expect 1
    print(c.value)   # expect still 1 (cached)
    return 0
  }
}