You can do it inefficiently and kinda manually in rust via weak pointers. Otherwise GC is basically the only way in rust. You can have tightly-scoped GC in rus

You can do it inefficiently and kinda manually in rust via weak pointers. Otherwise GC is basically the only way in rust. You can have tightly-scoped GC in rust that doesn't affect the runtime of everything else, though. No good such GCs exist right now. There are some type system tricks in hypothetical type systems you can do to make it possible to deal with these without runtime tracking. You can use the type system to ensure Detach traits get implemented, where Detach is for breaking cycles in a pass before destruction.