In a lot of cases I would consider a staged rewrite. Ie, I would turn what I could into dylibs going either from rust to c++ or c++ to rust. Assuming the code h

In a lot of cases I would consider a staged rewrite. Ie, I would turn what I could into dylibs going either from rust to c++ or c++ to rust. Assuming the code has structure and isn't infinite singletons and free standing functions this can make more or less sense. I'd translate the parts with the most likelihood for memory safety or thread safety issues first, so the transition could be part of the release cycle. It would still be a lot of work, but you might see benefits at intermediate releases this way.