Note that Rust will most likely be getting some support for these features too, at some point. It's what much of the academic PL research on borrow-checked languages is pointing towards. You can alreasy see some of the practical effect with "GhostCell" and similar proposals, even though these are arguably much too clunky and unintuituve for practical use (notably, they use obscure features of the Rust lifetime system to implement their equivalent of regions). Language-level support is likely to be rather easier to work with.