This Week in Rust 618

⚓ Rust 📅 2025-09-24 👤 surdeus 👁️ 8

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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.bsky.social on Bluesky 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 and archives can be viewed at this-week-in-rust.org. If you find any errors in this week's issue, please submit a PR.

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Updates from Rust Community

Official

Project/Tooling Updates

Observations/Thoughts

Rust Walkthroughs

Miscellaneous

Leading The Way For Safety Certified Rust: A Conversation With Espen Albrektsen Of Sonair

Crate of the Week

This week's crate is faer, a eneral-purpose linear algebra library for rust, with a focus on high performance for algebraic operations on medium/large matrices, as well as matrix decompositions.

Despite another week going by without a suggested weekly crate, llogiq is pleased with his choice.

Please submit your suggestions and votes for next week!

Calls for Testing

An important step for RFC implementation is for people to experiment with the implementation and give feedback, especially before stabilization.

If you are a feature implementer and would like your RFC to appear in this list, add a 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.

No calls for testing were issued this week by Rust, Rust language RFCs, Cargo or Rustup.

Let us know if you would like your feature to be tracked as a part of this list.

Call for Participation; projects and speakers

CFP - Projects

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!

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 or through a PR to TWiR or by reaching out on X (formerly Twitter) or Mastodon!

CFP - Events

Are you a new or experienced speaker looking for a place to share something cool? This section highlights events that are being planned and are accepting submissions to join their event as a speaker.

No Calls for papers or presentations were submitted this week.

If you are an event organizer hoping to expand the reach of your event, please submit a link to the website through a PR to TWiR or by reaching out on X (formerly Twitter) or Mastodon!

Updates from the Rust Project

430 pull requests were merged in the last week

Compiler

Library

Cargo

Rustdoc

rustdoc-search: javaScript optimization based on Firefox Profiler output

Clippy

Rust-Analyzer

Rust Compiler Performance Triage

Moving command-line argument quoting from C++ to Rust (#146700) resulted in a nice performance win when dealing with many dependencies and large workspaces. A somewhat costly destination propagation compiler pass was enabled by default (#142915), which resulted in some build time regressions, but should result in improved runtime performance. The rest of changes were small.

Triage done by @kobzol. Revision range: 52618eb3..ce4beebe

Summary:

(instructions:u)	mean	range	count
Regressions ❌ (primary)	0.3%	[0.1%, 1.9%]	61
Regressions ❌ (secondary)	0.6%	[0.1%, 3.4%]	90
Improvements ✅ (primary)	-0.5%	[-1.9%, -0.2%]	29
Improvements ✅ (secondary)	-1.3%	[-22.8%, -0.1%]	71
All ❌✅ (primary)	0.0%	[-1.9%, 1.9%]	90

1 Regression, 4 Improvements, 4 Mixed; 4 of them in rollups 37 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.

RFC: Add iter! macro

Upcoming Events

Rusty Events between 2025-09-24 - 2025-10-22 🦀

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.