Using move constructors to keep them updated is a design pattern. Most such datastructures either get implemented with Rc/Weak (which has a performance cost bu

Using move constructors to keep them updated is a design pattern. Most such datastructures either get implemented with Rc/Weak (which has a performance cost but often not a problem), or with "unsafe", which lets you write Rust as if it were more like C++ (you still have types, but you now also have certain dangerous abilities that you use carefully). Rust provides you the tools to properly abstract this unsafe such that it stays within the implementation and doesn't leak. This is true for Vec and BTreeMap, for example. You're talking about arguing with the compiler but unsafe Rust is not much worse than regular C++ in this aspect (there are some differences), so you always have the ability to drop down to this place where the compiler won't fight you to do stuff like this. Generally you can abstract away low level datastructures as unsafe code that's safe to use from the outside (this is usually something you can manageably audit) and everything else stays safe. Most such datastructures exist as libraries or in the stdlib already.