This has been proposed at the time, but it doesn't work for the case where the borrow points to stable memory (e.g. a `&str` pointing to the contents of a `Stri

This has been proposed at the time, but it doesn't work for the case where the borrow points to stable memory (e.g. a `&str` pointing to the contents of a `String` in the same struct). In general case a reference might point to either stable or unstable memory at runtime, so there's no way to make this always work (e.g. in async functions)