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 miette, a library for error handling that is beautiful both in code and output.

Thanks to Kat Marchán for the self-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

265 pull requests were merged in the last week

Rust Compiler Performance Triage

The largest story for the week are the massive improvements that come from enabling the new pass manager in LLVM which leads to consistent 5% to 30% improvements across almost all test cases. The regressions were mostly minor with clear paths for addressing the ones that were not made with some specific trade off in mind.

Triage done by @rylev. Revision range: 7743c9..83f147

4 Regressions, 4 Improvements, 3 Mixed; 0 of them in rollups

43 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.


No RFCs are currently in the final comment period.

Tracking Issues & PRs

New RFCs

No new RFCs were proposed this week.

Upcoming Events


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






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

Quote of the Week

This week we have two great quotes!

The signature of your function is your contract with not only the compiler, but also users of your function.

Quine Dot on rust-users

Do you want to know what was harder than learning lifetimes? Learning the same lessons through twenty years of making preventable mistakes.

Zac Burns in his RustConf talk

Thanks to Daniel H-M and Erik Zivkovic for the suggestions!

Please submit quotes and vote for next week!

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

Discuss on r/rust