/unstableSmartCastOnInvokeReceiver.kt:9:19: error: Reference has a nullable type '(() -> Int)?'. Use explicit '?.invoke' to make a function-like call instead.

/unstableSmartCastOnInvokeReceiver.kt:12:23: error: Smart cast to '() -> Int' is impossible, because 'interfaceMethod' is a property that has an open or custom getter. Use explicit '?.invoke' to make a function-like call instead.
