> Finally, reference counting can and will fragment heap. Is there anything that won’t fragment heap and simultaneously doesn’t insist on owning the world? It

> Finally, reference counting can and will fragment heap. Is there anything that won’t fragment heap and simultaneously doesn’t insist on owning the world? It is really, really painful to allow references to cross the GC heap boundary in both directions (witness the GNOME Shell not-a-memory-leak), and to me that is the principal reason: in a low-level language, you can RC only a bit of stuff, but you cannot really moving-GC only a bit of stuff. (I don’t expect an affirmative answer to this question as stated, but maybe some more basic abstraction for manual memory management would allow this?..)