@zkat The thing I like about slotmap is that you don't have to Rc<T> your graphs so there's potentially some efficiency gains. The SecondaryMap type also makes it possible to use the keys from the SlotMap for secondary storages, just like an #ECS.

QCell has various Cell types based on the #GhostCell research paper. You still need to use Rc<T> or Arc<T> for runtime garbage collection, but a &mut owner token gives you &mut access to the data.