julia

ad4c4af2 - added a few assertions in the GC to document a lock-free list invariant in code (#60324)

added a few assertions in the GC to document a lock-free list invariant in code (#60324) See PR title. I believe it's a good idea to document this property in code with an assertion, since it's a tricky invariant that makes it safe to use our current lock-free list implementation. In the long term, it might be better to use a lock-free list with an actual ABA-prevention mechanism to make the code more robust.