for those not familiar with Go, here's the problem translated in C terms: "I passed a pointer to your function and it called free() on it. how dare you!"
More "I passed a pointer to your function and it called free() on it, without documenting that it was taking ownership of the memory". Ownership contracts are an important part of the API of any function that does stuff with resources, whether memory, file descriptions, network connections, etc. If the API implies that it takes a pointer to a resource but will only read from or write to it, and then disposes of it, that's a bug.
I think that's a good point. It's often said that garbage collection helps prevent memory leaks, and it's also said often that memory isn't the only kind of resource which could be leaked.
Here is another case where weak- and dynamic-typing language features have come up in the context of resource management.
I'm not saying this one example proves anything, just that it might be interesting to be on the lookout for other events of this pattern.
No, that's not what the problem is. Translated to C++, the problem is "you passed a pointer to A∗, you dynamic_cast<>'d it to a subtype B∗ without documenting that you did so".
Not really. You can't dynamic_cast across across protected or private inheritance boundaries, even if the function attempting it is a friend. As long as your public inheritance hierarchy maintains your contract (and they should) you're fine.
