Externally Implementable Items

[nikomatsakis]

Metadata
Point of contact	@m-ou-se
Team(s)	compiler, lang
Goal document	2025h1/eii

Summary

We intend to implement Externally Implementable Items in the compiler.
The plan is to do so in a way that allows us to change the way #[panic_handler] and similar attributes are handled,
making these library features instead of compiler built-ins.
We intend to eventually support both statics and functions,
but the priority is at functions right now.

Tasks and status

• Discussion and moral support ()
• Lang-team experiment (lang )
• Lang-team champion (lang )
• Design experiment (syntax, etc.) ()
• Refactor attributes in rustc ()
• Implement experiment ()
• Standard reviews (compiler )
• Blog post inviting feedback ()
• Update RFC with new findings ()

[nikomatsakis]

This issue is intended for status updates only.

For general questions or comments, please contact the owner(s) directly.

[m-ou-se]

Now that rust-lang/rust#135726 is merged, @jdonszelmann and I will be working on implementing EII.

We have the design for the implementation worked out on our whiteboard. We don't expect any significant blockers at this point. We'll know more once we start writing the code next week.