// FILE: 1.kt package test public class Data() public class Input(val d: Data) : Closeable { public fun data() : Int = 100 } public class Output(val d: Data) : Closeable { public fun doOutput(data: Int): Int = data } public interface Closeable { open public fun close() {} } public inline fun T.use(block: (T)-> R) : R { var closed = false try { return block(this) } catch (e: Exception) { closed = true try { this.close() } catch (closeException: Exception) { } throw e } finally { if (!closed) { this.close() } } } public fun Input.copyTo(output: Output, size: Int): Long { return output.doOutput(this.data()).toLong() } // FILE: 2.kt import test.* fun Data.test1(d: Data) : Long { val input2 = Input(this) val input = Input(this) return input.use{ val output = Output(d) output.use{ input.copyTo(output, 10) } } } fun box(): String { val result = Data().test1(Data()) if (result != 100.toLong()) return "test1: ${result}" return "OK" }