I find that in #rustlang and elsewhere I sometimes really need a one-or-more representation (rather than zero-or-more). There are a number of crates that provide non-empty collections for this, but I've always found one thing or another missing.

There's still a lot to do (including API documentation), but I think I'm happy with the overall shape of my crate: Mitsein. AFAICT, it's one of the most comprehensive crates that attempts to tackle this problem. Feedback, issues, and PRs are welcome!

https://crates.io/crates/mitsein