Hello and welcome to another issue of This Week in Rust! Rust is a programming language empowering everyone to build reliable and efficient software. This is a weekly summary of its progress and community. Want something mentioned? Tag us at @ThisWeekInRust on Twitter or @ThisWeekinRust on mastodon.social, or send us a pull request. Want to get involved? We love contributions.

This Week in Rust is openly developed on GitHub. If you find any errors in this week's issue, please submit a PR.

This week's crate is Sniffnet, a cross-platform GUI application to analyze your network traffic.

Thanks to Gyuly Vgc for the suggestion!

Please submit your suggestions and votes for next week!

Call for Participation

Always wanted to contribute to open-source projects but did not know where to start? Every week we highlight some tasks from the Rust community for you to pick and get started!

No calls for participation this week. Keep an eye out for more places to contribute next week!

If you are a Rust project owner and are looking for contributors, please submit tasks here.

Updates from the Rust Project

291 pull requests were merged in the last week

Rust Compiler Performance Triage

Fairly busy week with some massive performance improvements at the expense of some significant albeit smaller regressions. The main wins came in a long-standing PR from @cjgillot to enable encoding spans in metadata relative to their enclosing item. This causes more work in full compilation which causes some regressions up to 5% but can lead to very large wins in incremental compilation scenarios (up to ~70%). For example, the clap crate compiles 68% faster after a small 1 line change than it did previously.

Triage done by @rylev. Revision range: b38a6d..b43596

Summary:

(instructions:u)	mean	range	count
Regressions ❌ (primary)	1.6%	[0.3%, 4.6%]	97
Regressions ❌ (secondary)	1.8%	[0.2%, 7.6%]	60
Improvements ✅ (primary)	-9.7%	[-68.7%, -0.2%]	53
Improvements ✅ (secondary)	-1.7%	[-15.3%, -0.1%]	62
All ❌✅ (primary)	-2.4%	[-68.7%, 4.6%]	150

1 Regressions, 1 Improvements, 4 Mixed; 1 of them in rollups 47 artifact comparisons made in total

Full report here

Approved RFCs

Changes to Rust follow the Rust RFC (request for comments) process. These are the RFCs that were approved for implementation this week:

No RFCs were approved this week.

Final Comment Period

Every week, the team announces the 'final comment period' for RFCs and key PRs which are reaching a decision. Express your opinions now.

RFCs

No RFCs entered Final Comment Period this week.

Tracking Issues & PRs

[disposition: merge] Only include stable lints in rustdoc::all group
[disposition: merge] Don't derive Debug for OnceWith & RepeatWith
[disposition: merge] PhantomData layout guarantees
[disposition: merge] Add O(1) Vec -> VecDeque conversion guarantee
[disposition: merge] Stabilize ::{core,std}::pin::pin!
[disposition: merge] Stabilize main_separator_str
[disposition: merge] Loosen the bound on the Debug implementation of Weak.

New and Updated RFCs

No New or Updated RFCs were created this week.

Call for Testing

An important step for RFC implementation is for people to experiment with the implementation and give feedback, especially before stabilization. The following RFCs would benefit from user testing before moving forward:

No RFCs issued a call for testing this week.

If you are a feature implementer and would like your RFC to appear on the above list, add the new call-for-testing label to your RFC along with a comment providing testing instructions and/or guidance on which aspect(s) of the feature need testing.

Upcoming Events

Rusty Events between 2023-01-04 - 2023-02-01 🦀

If you are running a Rust event please add it to the calendar to get it mentioned here. Please remember to add a link to the event too. Email the Rust Community Team for access.