In C++, "moving" and "copying" are a matter of class design. While you are expected to use move (resp. copy) constructors and assignments to, well, move (resp. copy); the language doesn't rule out using them for other purposes.
In Rust, assignment and argument passing always move, "moving" always does the right thing (make a shallow copy and invalidate the original object), and you can't override this behavior. Furthermore, Rust splits what C++ calls "copying" into two concepts: shallow copying (which is the same as moving, except the original object isn't invalidated, and the type checker guarantees you can only do it when it makes sense) and deep cloning (which may be expensive and needs to be explicitly requested by the programmer).
This is why Rust can track which objects are no longer usable.
In Rust, assignment and argument passing always move, "moving" always does the right thing (make a shallow copy and invalidate the original object), and you can't override this behavior. Furthermore, Rust splits what C++ calls "copying" into two concepts: shallow copying (which is the same as moving, except the original object isn't invalidated, and the type checker guarantees you can only do it when it makes sense) and deep cloning (which may be expensive and needs to be explicitly requested by the programmer).
This is why Rust can track which objects are no longer usable.