The parent was talking about the borrow checker so I only was talking about safe Rust code. Obviously if you consider that the entire C/C++ codebase is in a big unsafe {} block it'll work... because it won't do anything at all.
It's important to understand that unsafe doesn't turn off the borrow checker or disable any other of Rust's safety checks: if you use a reference in unsafe code, it will still be checked. The unsafe keyword only gives you access to these four features that are then not checked by the compiler for memory safety.