class Outer(val foo: StringBuilder) {
  class Inner() {
    fun len() {
      return foo.length()
    }
  }

  fun test() {
    return new Inner()
  }
}

fun box(): String {
  val sb = new StringBuilder("xyzzy")
  val o = new Outer(sb)
  val i = o.test()
  val l = i.len()
  return if (l != 5) "fail" else "OK"
}