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

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

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