Comment by Ericson2314

Shamelessly reposting my comment https://github.com/rust-lang/rfcs/pull/2052#issuecomment-312..., but I'm concerned about using semver for the tools, and what is effectively just a major version for the language.

This is backwards. Every new language feature should get its own minor version, and if tools never drop support, there is no need for a (tool) major version.