// WITH_STDLIB // WORKS_WHEN_VALUE_CLASS // LANGUAGE: +ValueClasses OPTIONAL_JVM_INLINE_ANNOTATION value class Foo(val s: Any) { fun isString(): Boolean = s is String } class Box(val x: T) fun box(): String { val f = Foo("string") val g = Box(f) val r = g.x.isString() if (!r) return "Fail" return "OK" }