In Kotlin, unlike Java, static members are not inherited by subclasses, even though they can be called inside a subclass without the base class name.
Outside a subclass, you have to call the base class static functions using the base class name:
WakefulBroadcastReceiver.completeWakefulIntent(intent) This behavior seems to lie within the companion objects concept: companion objects of classes in a hierarchy are not included into each other.