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 qcell, with a type that works like a compile-time RefCell.

Thanks to Soni L. 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 Rust Core

278 pull requests were merged in the last week

Rust Compiler Performance Triage

Fairly busy week, with some large improvements on several benchmarks. Several larger rollups landed, in part due to recovery from a temporary CI outage, and continued CI trouble since then. This is likely the cause for the somewhat unusual presence of rollups in our results.

Triage done by @simulacrum. Revision range: 69c4aa290..9f85cd6

2 Regressions, 2 Improvements, 4 Mixed; 2 of them in rollups

31 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:

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 are currently in the final comment period.

Tracking Issues & PRs

New RFCs

No new RFCs were proposed this week.

Upcoming Events


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





DEMV Systems


Polar Sync



Parity Technologies

Tweet us at @ThisWeekInRust to get your job offers listed here!

Quote of the Week


Niko and Daphne Matsakis on YouTube

Thanks to mark-i-m for the suggestion!

Please submit quotes and vote for next week!

This Week in Rust is edited by: nellshamrell, llogiq, and cdmistman.

Discuss on r/rust