Middle (Type-checker)
Leads: arielb1 / eddyb
Chat: WG-compiler-middle or #rustc on IRC

Getting started

The best way to start is to read this document, then join the chat and say hello! We’ll help you from there.


This working group is focused on the “core” of the compiler — that is, the type-checker and other associated checks. Our goal is to implement a number of pending RFCs or other features covering a large diversity of topics. For the most part, the implementation of these features can be done in any order.

Who to talk to?

If you’ve got questions, please reach out! People who hack actively in this area include:
For example, if you see an issue you would like to work on, but it doesn’t have mentoring instructions or the instructions are unclear, ping away! Even if these people don’t know the answer to your question, they should know who does.

Work items

The work items for this working group are tracked via issues in the rust-lang/rust github repository. You can also find them on the Rust “find-work” website

  • Want something to work on?
  • Want to help mentor others?

Decision items

Stabilizing never_type - how should we do this?
generalized method receivers - rust-lang/rust#27941
    need to decide what exactly is object-safe before we start implementing this. Or maybe not? Be unstable and unsound for a while.

PRs and completed work items 

  • Default binding modes has an open PR
  • Infer T: 'x bindings took a baby step; good start, even if still plenty to go!