For the use-case of optional pointers that don't have any ownership (and can possibly be updated mid-lifetime) and have a guaranteed external lifetime Those th

For the use-case of optional pointers that don't have any ownership (and can possibly be updated mid-lifetime) and have a guaranteed external lifetime Those three things seem like a pretty rare co-occurrence, if something has no ownership how can it have guaranteed external lifetime without being reference counted? I guess it's possible but in any scenario I come up with reference counting seems an easier way to do it.