The standard library codebase is a great place to try unstable language features, but we have to be careful about exposing them publicly. The following is a list of unstable language features that are ok to use within the standard library itself along with any caveats:
- Const generics
- Specialization
- Something missing? Please submit a PR to keep this list up-to-date!
Look out for any use of unstable language features in PRs, especially if any new #![feature] attributes have been added.