There is scope for moving/compacting GC, as long as creating a reference from a GC pointer is registered and pins a GC allocation in place until the reference d

There is scope for moving/compacting GC, as long as creating a reference from a GC pointer is registered and pins a GC allocation in place until the reference disappears (i.e. it will theoretically only be a cost with GC pointers, not anything else). Also it's worth noting that Rust does not have a GC yet, and I don't believe anyone has really got in there and iterated on possibilities yet. (Graydon, Felix (pnkfelix) and I have all done some experimentation with it, but all proof-of-concept/very basic, not really bullet-proof/production-ready things.)