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This post is auto-generated from RSS feed This Week in Rust. Source: This Week in Rust 633

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

• This Development-cycle in Cargo: 1.93
• Project goals update — December 2025

Newsletters

• This Month in Rust OSDev: December 2025
• The Embedded Rustacean Issue #62

Project/Tooling Updates

• Danube Messaging v0.6 - Introduces Schema Registry
• Releasing Fjall 3.0: log-structured key-value storage engine

Observations/Thoughts

• 1160 PRs to improve Rust in 2025
• [series] Who Owns the Memory? Part 3: How Big Is your Type?
• Even Safer Rust with Miri
• [uv] OnceMap: Rust Pattern for Running Concurrent Work Exactly Once
• Rust At Scale: Scaleway's Big Bet To Become THE European Hyperscaler

Rust Walkthroughs

• Introduction to SIMD programming in pure Rust
• Stop Forwarding Errors, Start Designing Them
• Designing APIs for the Pit of Success
• Rusty CDK, an Infrastructure as Code Experiment
• Ergonomic Async trait objects in Rust
• [video] Unlocking Cargo. Towards conncurrent cargo builds and cross workspace caching
• [audio] Netstack.FM episode 21 — GraphQL and Rust with Tom Houlé
• That mockingbird won't sing: a mock API server in Rust
• [ES] GoF Design Patterns in Rust: Necessary or Optional?
• [video] Tock, an embedded OS in Rust, overview and demo (3 videos in playlist)

Research

• How Safe is the Rust Ecosystem? A Deep Dive into crates.io

Crate of the Week

This week's crate is kameo, an asynchronous actor framework with clear, trait-based abstractions for actors and typed messages.

Thanks to edgimar for the 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, Rustup or Rust language RFCs.

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 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 2026-01-18 | Utrecht, The Netherlands | 2026-05-19 - 2026-05-20
• RustConf 2026 | CFP closes 2026-02-16 | Montreal, Quebec, Canada | 2026-09-08 - 2026-09-10

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

341 pull requests were merged in the last week

Compiler

• make inliner cycle detection a fallible process
• remove Span from segments of AttrPath

Library

• oneshot Channel
• add VecDeque::splice
• add specialization for deque1.prepend(deque2.drain(range)) (VecDeque::prepend and extend_front)
• avoid index check in char::to_lowercase and char::to_uppercase
• make specialization of Vec::extend and VecDeque::extend_front work for vec::IntoIter with any Allocator, not just Global
• implement TryFrom<char> for usize
• improve alloc Vec::retain_mut performance

Cargo

• feat(report): add cargo report rebuilds
• feat(test-support): Use test name for dir when running tests
• fix(log): add dependencies field to UnitRegistered
• any build scripts can now use cargo::metadata=KEY=VALUE
• implement fine grain locking for build-dir
• refactor: migrate some cases to expect/reason

Clippy

• manual_div_ceil: Added check for variant x.next_multiple_of(y) / y
• transmuting_null: Check single expression const blocks and blocks
• do not make suggestion machine-applicable if it may change semantics
• fix bool_assert_comparison suggests wrongly for macros
• fix implicit_saturating_sub suggests wrongly on untyped int literal
• fix multiple_inherent_impl false negatives for generic impl blocks
• fix needless_for_each false negative when for_each is in the expr of a block
• fix new_without_default misses where clause in new
• fix redundant_pattern_matching misses ) in suggestion span
• fix cmp_owned wrongly unmangled macros
• move multiple_bound_locations to style

Rust-Analyzer

• add useless prefix try_into_ for suggest_name
• allow finding references from doc comments
• add #[rust_analyzer::macro_style()] attribute to control macro completion brace style
• add location links for generic parameter type hints
• fix incorrect dyn hint in impl Trait for
• fix source text
• don't fire non_camel_case_types lint for structs/enums marked with repr(C)
• have an upvars_mentioned() query that only computes what upvars a closure captures
• suppress false positive missing assoc item diag on specialization
• implement Span::line() and Span::column() for proc-macro server
• migrate move_arm_cond_to_match_guard assist to use SyntaxEditor
• compress token trees for best memory usage
• only compute lang items for #![feature(lang_items)] crates
• re-use scratch allocations for try_evaluate_obligations
• pre-allocate intern storages with 64kb of data / 1024 elements
• proc-macro-srv: support file and local_file via bidirectional callbacks

Rust Compiler Performance Triage

Not many PRs were merged, as it was still mostly a holiday week. #149681 caused small regressions across the board, this is pending investigation.

Triage done by @kobzol. Revision range: 112a2742..7c04f5d2

Summary:

(instructions:u)	mean	range	count
Regressions ❌ (primary)	0.5%	[0.1%, 1.4%]	146
Regressions ❌ (secondary)	0.6%	[0.0%, 3.5%]	91
Improvements ✅ (primary)	-3.1%	[-4.7%, -1.5%]	2
Improvements ✅ (secondary)	-0.7%	[-6.4%, -0.1%]	15
All ❌✅ (primary)	0.4%	[-4.7%, 1.4%]	148

2 Regressions, 0 Improvements, 7 Mixed; 4 of them in rollups 51 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: * build-std: context

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.

Tracking Issues & PRs

Rust

• refactor: remove Ord bound from BinaryHeap::new etc
• regression: "the parameter type T may not live long enough" in offset_of!
• Tracking Issue for peekable_next_if_map

Compiler Team (MCPs only)

• Lint unsupported, target-specifc codegen flags

No Items entered Final Comment Period this week for Cargo, Rust RFCs, Leadership Council, Language Team, Language Reference 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

• RFC: Trait Implementation Privacy with permits

Upcoming Events

Rusty Events between 2026-01-07 - 2026-02-04 🦀

Virtual

• 2026-01-07 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-01-07 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2026-01-08 | Virtual (Charlottesville, VA, US) | Charlottesville Rust Meetup
  • Meet, swap, and learn!
• 2026-01-08 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2026-01-13 | Virtual | libp2p Events
  • rust-libp2p Open Maintainers Call
• 2026-01-13 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday
• 2026-01-13 | Virtual (Tel Aviv-yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Live Open Source Rust project contribution
• 2026-01-15 | Hybrid (Seattle, WA, US) | Seattle Rust User Group
  • Janurary, 2026 SRUG (Seattle Rust User Group) Meetup
• 2026-01-15 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 2026-01-18 | Virtual (Tel Aviv-yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Live Open Source Rust project contribution
• 2026-01-20 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2026-01-21 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-01-21 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Stack Safety
• 2026-01-27 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Fourth Tuesday
• 2026-01-28 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-01-29 | Virtual (Amsterdam, NL) | Bevy Game Development
  • Bevy Meetup #12
• 2026-01-29 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 2026-01-29 | Virtual (Charlottesville, VA, US) | Charlottesville Rust Meetup
  • Tock OS Part #2 - Rusty processes, memory limits, and basic capsules
• 2026-02-04 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing

Asia

• 2026-01-07 | Tel Aviv-yafo, IL | Rust 🦀 TLV
  • In person Rust January 2026 at AWS in Tel Aviv
• 2026-01-08 | Seoul, KR | Seoul Rust (Programming Language) Meetup
  • Seoul Rust Meetup
• 2026-01-17 | Delhi, IN | Rust Delhi
  • Rust Delhi Meetup #12

Europe

• 2026-01-07 | Amsterdam, NL | Rust Developers Amsterdam Group
  • Meetup @ Instruqt
• 2026-01-08 | Geneva, CH | Post Tenebras Lab
  • Rust Meetup Geneva
• 2026-01-14 | Girona, ES | Rust Girona
  • Rust Girona Hack & Learn 01 2026
• 2026-01-14 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup
• 2026-01-16 | Edinburgh, UK | Rust and Friends
  • Rust and Friends (daytime coffee)
• 2026-01-20 | Leipzig, SN, DE | Rust - Modern Systems Programming in Leipzig
  • Topic TBD
• 2026-01-20 | Paris, FR | Rust Paris
  • Rust meetup #82
• 2026-01-21 | Cambridge, UK | Cambridge Rust Meetup
  • Monthly Rust Meetup
• 2026-01-26 | Augsburg, DE | Rust Meetup Augsburg
  • Rust Meetup #17
• 2026-01-28 | Dortmund, DE | Rust Dortmund
  • Rust Dortmund Meetup - January 2026
• 2026-02-04 | Oxford, UK | Oxford ACCU/Rust Meetup.
  • Paul Grenyer: Beyond the Code: Designing Services That Stand the Test of Time

North America

• 2026-01-08 | Lehi, UT, US | Utah Rust
  • Bringing the data lake to the browser with WASM
• 2026-01-08 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2026-01-08 | Portland, OR, US | PDXRust
  • Toasty: An Easy-to-use Object-Relational Mapping for Rust
• 2026-01-08 | San Diego, CA, US | San Diego Rust
  • San Diego Rust January Meetup - Back in person!
• 2026-01-10 | Boston, MA, US | Boston Rust Meetup
  • Central Cambridge Rust Lunch, Jan 10
• 2026-01-13 | New York, NY, US | Rust NYC
  • Rust NYC Panel: AI Coding Agents in Rust: What Works, What Breaks
• 2026-01-14 | Chicago, IL, US | Chicago Rust Meetup
  • Rust Happy Hour
• 2026-01-15 | Hybrid (Seattle, WA, US) | Seattle Rust User Group
  • Janurary, 2026 SRUG (Seattle Rust User Group) Meetup
• 2026-01-17 | Boston, MA, US | Boston Rust Meetup
  • Boston Common Rust Lunch, Jan 17
• 2026-01-17 | Herndon, VA, US | NoVaLUG
  • Monthly Meeting - Make Brian Lunduke Angry, Program in Rust
• 2026-01-20 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2026-01-21 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2026-01-22 | Boston, MA, US | Boston Rust Meetup
  • Evening Boston Rust Meetup with Jiff, January 22
• 2026-01-22 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2026-01-24 | Boston, MA, US | Boston Rust Meetup
  • Davis Square Rust Lunch, Jan 24
• 2026-01-28 | Los Angeles, CA, US | Rust Los Angeles
  • Rust Los Angeles: Building Git-LFS Replacements in Rust
• 2026-01-29 | Atlanta, GA, US | Rust Atlanta
  • Rust-Atl
• 2026-01-29 | Nashville, TN, US | Music City Rust Developers
  • Rust Programming 101
• 2026-01-31 | Boston, MA, US | Boston Rust Meetup
  • Northeastern Rust Lunch, Jan 31

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

I find it amazing that by using Rust and Miri I am using tools that are on the edge of fundamental research in Programming Languages. Actual practically usable tools that anyone can use, not arcane code experiments passed around between academics.

– ZiCog on rust-users

Thanks to Kyllingene 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

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