Thanks! The increased memory overhead would seem to be a problem, but in the programs I work on at least (games, web servers, compilers), the vast majority of

Thanks! The increased memory overhead would seem to be a problem, but in the programs I work on at least (games, web servers, compilers), the vast majority of references in a program are owning references which aren't fat pointers. Non-owning references are very short-lived and on the stack, so the memory overhead shouldn be pretty minor in practice. Also, if we want to save a little more space, we can reduce the generations to 32 bits (we're leaning this way in fact, as it opens the door to some interesting other features).