Bring the Async Rust experience closer to parity with sync Rust

[nikomatsakis]

Metadata
Point of contact	@tmandry
Team(s)	compiler, lang, libs-api, spec, types
Goal document	2025h1/async

Summary

Over the next six months, we will continue bringing Async Rust up to par with "sync Rust" by doing the following:

• Telling a complete story for the use of async fn in traits, unblocking wide ecosystem adoption,
• Improving the ergonomics of Pin, which is frequently used in low-level async code, and
• Preparing to support asynchronous (and synchronous) generators in the language.

Tasks and status

Overall program management

• AFIT story blog post (@tmandry)

Return type notation

• Initial implementation (@compiler-errors)
• Author RFC (@nikomatsakis)
• RFC decision (lang )
• Finished implementation (@compiler-errors)
• Lang-team champion (lang )
• Standard reviews (types, compiler )
• Author stabilization report (@compiler-errors)
• Author specification 1st draft (@compiler-errors, @tmandry, @nikomatsakis)
• Finalize specification text (spec )
• Stabilization decision (lang, types )

Unsafe binders

• Initial implementation (@compiler-errors)
• Author RFC (@nikomatsakis)
• Lang-team champion (lang )
• RFC decision (lang, types )

Implementable trait aliases

• Author RFC (@tmandry)
• Implementation (@compiler-errors)
• Lang-team champion (lang )
• Standard reviews (types, compiler )
• RFC decision (lang, types )

async fn in dyn Trait

• Lang-team experiment (@nikomatsakis)
• Lang-team champion (lang )
• Implementation (@compiler-errors)

Pin ergonomics

• Implementation (@eholk)
• Author RFC (@eholk)
• Lang-team experiment (lang )
• Lang-team champion (lang )

Trait for generators (sync)

• Implementation (@eholk)
• Author RFC
• RFC decision (libs-api, lang )
• Design meeting (lang )
• Lang-team champion (lang )

Dynosaur 1.0

• Implementation (@spastorino)
• Standard reviews (@tmandry)