> What is the correct procedure for this?
in general to work on something that will get "into the rust compiler" it needs at least an RFC and then a Major Change Proposal [0]
in practice it starts with asking on zulip [1]
[0] https://forge.rust-lang.org/compiler/proposals-and-stabiliza...
[1] https://forge.rust-lang.org/how-to-start-contributing.html
Asking on zulip is the good first step, yes. But RFC or MCP is only needed for bigger changes. Majority of changes will not need that, especially the ones contributed by newcomers.