A lang team initiative is some active effort with a clear goal or deliverable. Typically initiatives are changes to the language, but they could also be documentation, specifications, or something internal to the lang team.

Active initiatives

The following is a list of active lang-team initiatives. Each initiative has a link to a repository or tracking issue that goes into details on its current state, along with an owner and a liaison.


  • 🛑 -- Blocked (link to an issue)
  • ⏳ -- Paused
  • 🔬 -- Under active research
  • 💻 -- Under active development
  • 🚀 -- Feature complete and seeking feedback
  • ✅ -- Stable
Impl Traitnikomatsakis?
↳ Type Alias Impl Trait💻▰▰▰▱▱oli-obknikomatsakis
Generic Associated Types💻▰▰▰▱▱jackh726nikomatsakis
Async Foundationstmandrynikomatsakis
Async fundamentals🔬▱▱▱▱▱tmandrynikomatsakis
Never type🔬▰▰▱▱▱mark-simulacrumnikomatsakis
Inline assemblyAmanieuJoshTriplett
↳ Core feature🚀▰▰▰▰▱AmanieuJoshTriplett
↳ Const support🛑▰▰▱▱▱
Dyn upcasting💻▰▰▰▱▱crlf0710nikomatsakis
Negative impls in coherence🔬▰▰▱▱▱nikomatsakispnkfelix
FFI UnwindBatmanAodnikomatsakis
↳ extern "C-unwind"🚀▰▰▰▰▱BatmanAodnikomatsakis
↳ longjmp▰▰▱▱▱BatmanAodnikomatsakis
Try and generalized ?
? operator▰▰▰▰▰
Try trait🚀▰▰▰▰▱scottmcm?
try blocks▰▰▰▱▱scottmcm

Note that this list doesn't represent the complete set of unstable features. We are currently in the process of transitioning into the initiative system, so there are a number of RFCs that have been accepted (and even implemented!) which don't have an active initiative.

Proposed initiatives

You can see the currently proposed initiatives on Github.

How does one propose a new initiative?

Read more in the process page!