My compiler analysis says that if you have two possible pointers that a capability might come from, like in your first example, then you get no capability at al

My compiler analysis says that if you have two possible pointers that a capability might come from, like in your first example, then you get no capability at all. I think that's a better semantics than picking some capability at random. If you want to be explicit about where the capability comes from, use `zmkptr`.