Just so no one's deterred, it's actually not very difficult to do this. The rustc and ruby patches I submitted as an exercise. I went to the issue tracker, sort

Just so no one's deterred, it's actually not very difficult to do this. The rustc and ruby patches I submitted as an exercise. I went to the issue tracker, sorted by oldest first, and then picked the first issue that had little/no discussion on it. I purposefully avoided picking an issue with significant architectural impact or political context this way. So there's also not much designing and reviewing needed. The merge requests were assigned to very senior reviewers each time. The automated test suites made sure I didn't waste much of anyone's time with trivial errors. Of course the requirement is that you're actually at least proficient with the languages (C for Ruby and Rust for rustc) but beyond that I think anyone can do it with a couple of sunday afternoons spent diligently digging through the codebase.