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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Official

• Lessons learned from the Rust Vision Doc process
• Updating Rust’s Linux musl targets to 1.2.5
• Making it easier to sponsor Rust contributors

Newsletters

• The Embedded Rustacean Issue #60

Project/Tooling Updates

• Yew 0.22 - For Real This Time
• Ferrocene 25.11.0 now available!
• YM2149-rs 0.8.0 — Cycle-accurate YM2149/AY-3-8910 chiptune ecosystem
• Duper’s new superpowers!
• Announcing redis-rs 1.0.0 release
• Announcing diesel-guard 0.2.0: Catch unsafe PostgreSQL migrations before they hit production
• [video] Recording from the Rust Seoul meetup: Zia, a programming language that defines itself (written in Rust)

Observations/Thoughts

• Exploring deboa-macros: Ergonomic HTTP Client Macros for Rust
• Fighting the Client Spaghetti Monster with Rust Traits
• Rust unit testing: buffered file reading
• Firecracker deep dive: How Rust and microVMs are revolutionizing cloud infrastructure
• iksemel rusted
• Postfix Macros and let place
• Should we get rid of clippy::manual_try_fold?

Rust Walkthroughs

• Get in Line - superfast SPSC Queue
• Emulating avx-512 intrinsics in Miri
• How to speed up the Rust compiler in December 2025
• From trees to graphs: speeding up vector search 10x with Hannoy
• [series] Part 1: Tokenization, Building an LLM From Scratch in Rust

Miscellaneous

• Pydantic: The Python Darling That Loves Rust
• [video] AWS re:Invent 2025 - Unleash Rust’s potential on AWS (DEV307)

Crate of the Week

This week’s crate is mdbook-lint, a markdown linter geared towards mdbook, but useful with any markdown.

Thanks to josh rotenberg for the self-suggestion!

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, Cargo, Rust language RFCs 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.

No Calls for participation were submitted this week.

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 Bluesky 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.

• RustWeek 2026 | CFP closes 2025-12-31 | Utrecht, The Netherlands | 2026-05-19 - 2026-05-20

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 Bluesky or Mastodon!

Updates from the Rust Project

494 pull requests were merged in the last week

Compiler

• early return on duplicate span lowerings
• miri: support fstat in linux

Library

• c_variadic: make VaList abi-compatible with C
• add #[inline] to Layout::is_size_align_valid
• add Option::into_flat_iter
• also introduce Peekable::next_if_map_mut next to next_if_map
• assume the returned value in .filter(…).count()
• implement Allocator for &mut A where A: Allocator + ?Sized
• implement Vec::from_fn
• remove initialized-bytes tracking from BorrowedBuf and BorrowedCursor
• stabilize array_windows

Cargo

• lint: new implicit_minimum_version_req lint
• timings: derive concurrency data from unit data
• lints: handle lints separately at ws pkg level
• clean: Optimize (legacy) clean with multiple -p specifiers
• don’t read the config file twice when $CARGO_HOME is a symlink
• support for rustdoc mergeable cross-crate info

Clippy

• len_without_is_empty: allow is_empty(&self) with len(&mut self)
• fix map_entry false positive when it would cause MutexGuard to be held across an
• fix nonstandard_macro_braces false negative on macros with empty args
• fix panicking_unwrap false positive on field access with implicit deref
• fix tuple_array_conversions false positive when binded vars are used before conversion
• fix useless_conversion wrongly unmangled macros
• fix broken while_let_on_iterator suggestion for non-sized types

Rust-Analyzer

• add config hide placeholders type hints
• fix make::unnamed_param result a untyped_param
• fix nested expr missing semicolon in incomplete-let
• fix pub in enum variant field for no_such_field
• allow multiple discover operations
• don’t implement sizedness check via all_field_tys()
• fix completion in format strings
• fixed impl display to show trait generic args
• more proc-macro-srv proto fixes
• register define_opaque builtin attribute macro
• resolve const generic param-env panic in type projection
• skip cfg attributes in macro input attribute stripping
• no complete unit RetType in resugar async assoc item

Rust Compiler Performance Triage

Overall result is negative this week, but both main regressions are on track to be addressed. No outstanding changes otherwise.

Triage done by @panstromek. Revision range: eca9d93f..55495234

Summary:

(instructions:u)	mean	range	count
Regressions ❌ (primary)	0.4%	[0.1%, 4.3%]	111
Regressions ❌ (secondary)	0.4%	[0.1%, 2.2%]	97
Improvements ✅ (primary)	-1.0%	[-1.3%, -0.7%]	2
Improvements ✅ (secondary)	-0.2%	[-0.3%, -0.0%]	9
All ❌✅ (primary)	0.4%	[-1.3%, 4.3%]	113

3 Regressions, 2 Improvements, 3 Mixed; 3 of them in rollups 30 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 entered Final Comment Period this week.

Every week, the team announces the ‘final comment period’ for RFCs and key PRs which are reaching a decision. Express your opinions now.

Tracking Issues & PRs

Rust

• Warn on codegen attributes on required trait methods
• NFC normalize lifetime identifiers
• don’t normalize where-clauses when checking well-formedness

Compiler Team (MCPs only) * Destabilise target-spec-json

Rust RFCs * RFC: #[export_visibility = ...] attribute

No Items entered Final Comment Period this week for Cargo, Language Team, Language Reference, Leadership Council or Unsafe Code Guidelines.

Let us know if you would like your PRs, Tracking Issues or RFCs to be tracked as a part of this list.

New and Updated RFCs

• No New or Updated RFCs were created this week.

Upcoming Events

Rusty Events between 2025-12-10 - 2026-01-07 🦀

Virtual

• 2025-12-10 | Virtual (Girona, ES) | Rust Girona

• Sessió setmanal de codificació / Weekly coding session

• 2025-12-11 | Hybrid (Seattle, WA, US) | Seattle Rust User Group

• December, 2025 SRUG (Seattle Rust User Group) Meetup

• 2025-12-11 | Virtual (Nürnberg, DE) | Rust Nuremberg

• Rust Nürnberg online

• 2025-12-16 | Virtual (Washington, DC, US) | Rust DC

• Mid-month Rustful

• 2025-12-17 | Virtual (Girona, ES) | Rust Girona

• Sessió setmanal de codificació / Weekly coding session

• 2025-12-17 | Hybrid (Vancouver, BC, CA) | Vancouver Rust

• Rust Study/Hack/Hang-out

• 2025-12-18 | Virtual (Berlin, DE) | Rust Berlin

• Rust Hack and Learn

• 2025-12-23 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup

• Fourth Tuesday

• 2025-12-25 | Virtual (Nürnberg, DE) | Rust Nuremberg

• Rust Nürnberg online

• 2026-01-01 | Virtual (Berlin, DE) | Rust Berlin

• Rust Hack and Learn

• 2026-01-03 | Virtual (Kampala, UG) | Rust Circle Meetup

• Rust Circle Meetup

• 2026-01-07 | Virtual (Indianapolis, IN, US) | Indy Rust

• Indy.rs - with Social Distancing

Asia

• 2025-12-13 | Kuala Lumpur, MY | Rust Malaysia

• FULL: Advent of Code Year End Hack

• 2025-12-14 | Beijing, CN | Voice AI and Rust Meetup (Rust for AI, lowcoderust.com)

• GDPS语音AI agent WorkShop+Meetup

• 2025-12-20 | Bangalore, IN | Rust Bangalore

• December 2025 Rustacean meetup

• 2026-01-06 | Tel Aviv-yafo, IL | Rust 🦀 TLV

• In person Rust January 2026 at AWS in Tel Aviv

Europe

• 2025-12-10 | London, UK | Rust London User Group

• Rust LDN Talks: Christmas Party with London Gophers & Red Badger

• 2025-12-10 | München, DE | Rust Munich

• Rust Munich 2025 / 4 - Hacking Evening

• 2025-12-10 | Reading, UK | Reading Rust Workshop

• Reading Rust Meetup

• 2025-12-11 | Geneva, CH | PostTenebrasLab

• Rust Meetup Geneva

• 2025-12-15 | Trondheim, NO | Rust Trondheim

• Rust Advent of Code Hackathon

• 2025-12-16 | Bergen, NO | Rust Bergen

• Rust Bergen #3 @ Zrch

• 2025-12-16 | Copenhagen, DK | Copenhagen Rust Community

• Rust Hack Night #12: Advent of Code

• 2025-12-16 | Leipzig, SN, DE | Rust - Modern Systems Programming in Leipzig

• Topic TBD

• 2025-12-19 | Lyon, FR | Rust Lyon

• Rust Lyon Meetup #11

• 2026-01-07 | Girona, ES | Rust Girona

• Rust Girona Hack & Learn 01 2026

North America

• 2025-12-10 | Chicago, IL, US | Chicago Rust Meetup

• Rust Happy Hour

• 2025-12-11 | Lehi, UT, US | Utah Rust

• Competetive Robotics with Rust

• 2025-12-11 | Mountain View, CA, US | Hacker Dojo

• RUST MEETUP at HACKER DOJO

• 2025-12-11 | San Diego, CA, US | San Diego Rust

• San Diego Rust December Meetup - Back in person!

• 2025-12-11 | Hybrid (Seattle, WA, US) | Seattle Rust User Group

• December, 2025 SRUG (Seattle Rust User Group) Meetup

• 2025-12-13 | Boston, MA, US | Boston Rust Meetup

• Alewife Rust Lunch, Dec 13

• 2025-12-16 | San Francisco, CA, US | San Francisco Rust Study Group

• Rust Hacking in Person

• 2025-12-17 | Austin, TX, US | Rust ATX

• Rust Lunch - Fareground

• 2025-12-17 | Hybrid (Vancouver, BC, CA) | Vancouver Rust

• Rust Study/Hack/Hang-out

• 2025-12-17 | Spokane, WA, US | Spokane Rust

• Year-End Social Meetup w/ Python, Rust, and Others Local User Groups

• 2025-12-20 | Boston, MA, US | Boston Rust Meetup

• Back Bay Rust Lunch, Dec 20

• 2026-01-01 | Saint Louis, MO, US | STL Rust

• Cancelled

Oceania

• 2025-12-11 | Brisbane City, QL, AU | Rust Brisbane

• Rust Meetup Dec 2025

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.

Jobs

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

Quote of the Week

[..] if a breaking change is going to happen, it’s much better to make lock automatically panic than to make panics silently unlock.

– Rain on their blog

Thanks to hkBst for the suggestion!

Please submit quotes and vote for next week!

This Week in Rust is edited by:

• nellshamrell
• llogiq
• ericseppanen
• extrawurst
• U007D
• mariannegoldin
• bdillo
• opeolluwa
• bnchi
• KannanPalani57
• tzilist

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust