Discussion about all "official" (rust-lang managed) non-rustc tools, and community infrastructure:

Discussion about the compiler itself -- internal data structures and algorithms, optimizations, parsing, and so on. Home of the compiler subteam.

Discussion on designs for new language features and other user-facing language changes. Home of the language design team.

Discussion around libraries, either in the community or officially supported (hosted by rust-lang).

Discussion about this forum, its organization, how it works, and how we can improve it.

Community happenings, such as talks, meetups, group projects, etc.

Low-traffic category for announcements about the decision making process, such as when RFCs are entering the final comment period, new meeting minutes are available, and so forth.

Discussion about the documentation, either the prose docs or the API docs.

A category for discussion about the behavior of rustfmt (with a focus on what the defaults ought to be). See RFC 1607 for more details.

This category is for giving feedback on the various websites maintained by Rust's Web Presence team, including www.rust-lang.org, crates.io, and docs.rs! Feedback should be primarily focused feature and design improvements to the websites. Please file technical bugs and content errors or typos on the respective GitHub repository instead.

Discussion about the Rust Guidelines. Available rendered here and as source. Use the "style" subcategory as appropriate!

Use this category to report your experiences, positive and negative, with the 2018 Edition! See this post for more.