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? Tweet us at @ThisWeekInRust 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.

Updates from Rust Community



Project/Tooling Updates


Rust Walkthroughs


Crate of the Week

This week's crate is cap-std a std-replacement that introduces capabilities to facilitate defense-in-depth sandboxing.

Thanks to Kinrany for the suggestion!

Please submit your suggestions and votes for next week!

Call for Participation

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

Some of these tasks may also have mentors available, visit the task page for more information.

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

Updates from the Rust Project

388 pull requests were merged in the last week

Rust Compiler Performance Triage

Overall, a positive week for compiler performance with regressions mainly being relegated to smaller issues. This can be see by the fact that 95 test cases in real world crates were improvements while regressions only happened in 22 test cases. The largest improvement was by @nnethercote where the compilation of #[derive(Debug)] was improved. This led to an average of 1% improvement in compile times across 124 real world crate test cases.

Triage done by @rylev. Revision range: abace0..baf382


mean max count
Regressions 😿
0.6% 2.4% 22
Regressions 😿
0.5% 1.0% 35
Improvements 🎉
-1.1% -5.2% 95
Improvements 🎉
-2.3% -10.3% 35
All 😿🎉 (primary) -0.8% -5.2% 117

3 Regressions, 3 Improvements, 4 Mixed; 5 of them in rollups 34 artifact comparisons made in total

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:

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.

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.


  • No RFCs entered Final Comment Period this week.

Tracking Issues & PRs

New and Updated RFCs

Upcoming Events

Rusty Events between 2022-06-29 - 2022-07-27 🦀




North America

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.

Rust Jobs

We have made some changes to our jobs section, please see this GitHub issue for an explanation and the most current Who's Hiring thread on r/rust for job postings.

Quote of the Week

JG: mem::replace / mem::swap === Indiana Jones swapping the artifact for a bag of sand in a temple

CV: except rustc would tell Indy that's a type mismatch

JG: Yes, that would be the boulder, I assume.

Older compilers were more aggressive in error reporting.

Jake Goulding and Cuviper on the Rust Zulip

Thanks to Josh Triplett for the suggestion.

Please submit quotes and vote for next week!

This Week in Rust is edited by: nellshamrell, llogiq, cdmistman, ericseppanen, extrawurst, andrewpollack, U007D, kolharsam, joelmarcey, mariannegoldin.

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