Tracking Issue for `async_fn_in_dyn_trait`

[compiler-errors]

This is a tracking issue for dyn-compatible traits with async functions in them, called "async functions in dyn trait".
The feature gate for the issue is #![feature(async_fn_in_dyn_trait)].

About tracking issues

Tracking issues are used to record the overall progress of implementation. They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions. A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature. Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

• Approve as lang experiment.
• Implement in nightly.
  • Add unpolished, experimental support for AFIDT (async fn in dyn trait) #133122
• Accept an RFC.
• Add documentation to the dev guide.
  • See the instructions.
• Add documentation to the reference.
  • See the instructions.
• Add formatting for new syntax to the style guide.
  • See the nightly style procedure.
• Stabilize.
  • See the instructions.

Unresolved Questions

TODO.

Related

TODO.

cc @rust-lang/lang

[compiler-errors]

Nominating this since I think it may technically need a new lang team experiment, since https://rust-lang.github.io/rfcs/3185-static-async-fn-in-trait.html only RFC'd static AFIT behavior. I would expect @nikomatsakis will shepherd this from the lang side.

[nikomatsakis]

Happy to shepherd

[traviscross]

@rustbot labels -I-lang-nominated +B-experimental

We discussed this in lang triage today and were all enthusiastic to approve an experiment here with @nikomatsakis to liaison. We look forward to seeing the results of this.

Thanks to @compiler-errors for pushing forward on this.