We are changing where to file issues a little bit. From now on, issues should only be filed on the Rust repo for implementation issues, bugs, or meta-issues. Issues which deal with language design or are major changes to the libraries or are feature requests should be filed on the RFCs repo. In short, anything that would require an RFC before implementation should be on the RFCs repo.
At some point in the next few days I will transfer any existing issues that are RFC-like from the Rust repo to the RFCs repo. All comments will be preserved.
Please note that filing an issue on the RFCs repo is not a substitute for a proper RFC as a PR. Ideas for change to Rust are only likely to get serious attention if there is an RFC. The motivation for issues on the RFCs repo is so that we can track feature requests etc. before they are ready for a RFC.