That's the way it's resolved in languages with a standard, multiple compilers and no preference towards any of the compilers. This doesn't mean it has to be done this way in Rust.

It seems like Rust is leaning towards doing that like it's done in python. One reference implementation, a language reference and a bunch of design documents (PEP, RFC). There are some areas where the language reference is lacking right now but that can be, and is being, fixed over time.