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 bytehound a memory profiler for Rust.

Thanks to Aleksey Kladov 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

412 pull requests were merged in the last week

Rust Compiler Performance Triage

A somewhat difficult week to triage due to the large amount of noise coming from two benchmarks. Hopefully this noise settles down in the future. Other than that, improvements much outweighed regressions with an average of 142 changes to instruction count averaging 0.7% improvement. There were no huge wins this week, however.

Triage done by @rylev. Revision range: 4a24f08b..0631ea5d


(instructions:u) mean range count
Regressions ❌
1.0% [0.2%, 2.6%] 4
Regressions ❌
1.3% [0.3%, 2.6%] 23
Improvements ✅
-0.7% [-2.8%, -0.2%] 138
Improvements ✅
-1.3% [-2.7%, -0.2%] 71
All ❌✅ (primary) -0.7% [-2.8%, 2.6%] 142

2 Regressions, 3 Improvements, 10 Mixed; 6 of them in rollups 40 artifact comparisons made in total

Full report

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.

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 entered Final Comment Period this week.

Tracking Issues & PRs

New and Updated RFCs

Upcoming Events

Rusty Events between 2022-08-31 - 2022-09-28 🦀



North America


South 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.


Please see the latest Who's Hiring thread on r/rust

Quote of the Week

[W]e reached a tipping point. We decided to move our entire codebase to Rust... . Rust seemed to give us all the capabilities we needed, however, there was still one minor problem - no one on the team knew Rust. ...

We started with a small team of senior engineers and managers learning Rust and developing the skeleton of the DB and dev environment (for others to build on). Then, slowly, others joined in rewriting and contributing different components until we eventually got rid of the old codebase altogether (I still remember the day my original C modules, from the first days of Pinecone, were taken out). Unbeknownst to most Pinecone customers, the new Rust core was deployed in March this year. And in the process of taking over running workloads, we managed not to drop a single API call!

... We all expect[ed] performance and dev processes to improve. Those indeed happened. What we didn’t expect was the extent to which dev velocity increased and operational incidents decreased. Dev velocity ... improved dramatically with Rust. Built-in testing, CI/CD, benchmarking, and an overzealous compiler increased engineers’ confidence in pushing changes, and enabled them to work on the same code sections and contribute simultaneously without breaking the code base. Most impressively though, real time operational events dropped almost to zero overnight after the original release. Sure, there are still surprises here and there but, by and large, the core engine has been shockingly stable and predictable.

Edo Liberty on the pinecone blog

Thanks to Erich Gubler 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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