class C { class D { fun foo(): Any { return {} } } } fun box(): String { val javaClass = C.D().foo().javaClass val enclosingMethod = javaClass.getEnclosingMethod() if (enclosingMethod?.getName() != "foo") return "method: $enclosingMethod" val enclosingClass = javaClass.getEnclosingClass() if (enclosingClass?.getSimpleName() != "D") return "enclosing class: $enclosingClass" val declaringClass = javaClass.getDeclaringClass() if (declaringClass != null) return "anonymous function has a declaring class: $declaringClass" return "OK" }