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.

Want TWIR in your inbox? Subscribe here.

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:

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

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust

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.

Want TWIR in your inbox? Subscribe here.

Updates from Rust Community

Project/Tooling Updates

• reqwest v0.13 - rustls by default
• rama 0.3.0-alpha.4 is released — modular service framework to move and transform network packets
• Ratatui 0.30.0 is released! - a Rust library for cooking up terminal user interfaces

Observations/Thoughts

• Four Years of Rust: An Odyssey of Failures, Achievements, and Hard Lessons
• Simple Bidirectional Type Inference
• serde's borrowing can be treacherous
• Garbage collection in Rust got a little better
• [audio] Netstack.FM episode 20 — Netstack.FM New Year Special, 2025 Wrap-Up

Rust Walkthroughs

• Why is calling my asm function from Rust slower than calling it from C?
• Rust Errors Without Dependencies
• [video] Building your first APP using the new Hotaru Web Framework!

Miscellaneous

• [audio] 2025 Holiday Special - Rust in Production Podcast
• Investigating and fixing a nasty clone bug

Crate of the Week

This week's crate is wgsl-bindgen, a binding generator for WGSL, the WebGPU shading language, to be used with wgpu.

Thanks to Artem Borisovskiy 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.

Rustup

• Rustup 1.29.0 beta: Call for Testing!

• Testing steps: See "How to Test" section from above link.

• No calls for testing were issued this week by Rust, Cargo 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.

• Spindalis - Create an AST parser
• Spindalis - Add procedural macro for definite integral
• Spindalis - Add a function and macro that can expand polynomials
• Spindalis - Add display trait to functions in spindalis core

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

297 pull requests were merged in the last week

Compiler

• recursive delegation improvements
• miri: fix ICE for particular data race situations
• miri: show a warning when combing native-lib mode and many-seeds
• miri: tree Borrows: improve protector end access child skipping

Library

• add MaybeDangling to core
• alloc: specialize String::extend for slices of str
• implement Duration::div_duration_{floor,ceil}
• implement flatten for Option<&Option<T>> and Option<&mut Option<T>>
• optimized implementation for uN::{gather,scatter}_bits
• rewrite String::replace_range
• stabilize lazy_get

Cargo

• index: Stabilize pubtime
• report: new command cargo report sessions
• report: support --manifest-path in cargo report timings
• resolver: List features when no close match
• toml: TOML 1.1 parse support
• vendor: recursively filter git files in subdirectories
• vendor: unpack from local-registry cache path
• build-rs: Reduce from 'build' to 'check' where possible
• experiment: render timing pipeline in SVG
• patch: Display where the patch was defined in patch-related error messages

Rustdoc

• if line number setting is disabled, do not make line numbers take space
• fix copy code example with line numbers
• fix duplicate Re-exports sections
• fix incorrect type filter name in help popup

Clippy

• fix assertions_on_constants false positive when there is non-constant value in the condition expr
• fix double_parens false positive on macro repetition patterns
• fix obfuscated_if_else wrongly unmangled macros
• fix result_large_err false negative on closures
• preserve explicit lifetime information when removing mut
• various fixes for handling of macros

Rust-Analyzer

• add bidirectional messaging proc-macro-srv prototype
• add macro segment completion
• implement configuration to change sub command for test, bench and doctest
• provide a setting to disable showing rename conflicts
• stabilize type mismatch diagnostic 🎉
• indent for convert_to_guarded_return
• fix LSP configuration request handling
• fix parsing of format_args!("...", keyword=...)
• fix type inference when hovering on _
• reenable fixpoint variance
• do not really expand builtin derives, instead treat them specifically
• pre-allocate some buffers in parsing
• reduce channel lock contention for drop-threads
• prompt the user in VSCode to add the rust-anaylzer componenet to the toolchain file

Rust Compiler Performance Triage

Not a lot of changes this week. Overall result is positive, largely thanks to #142881, which makes computing an expensive data structure for JumpThreading MIR optimization lazy.

Triage done by @panstromek. Revision range: e1212ea7..112a2742

Summary:

2 Regressions, 0 Improvements, 3 Mixed; 1 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.

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

Compiler Team (MCPs only)

• Proposal for a dedicated test suite for the parallel frontend
• Promote tier 3 riscv32 ESP-IDF targets to tier 2
• Proposal for Adapt Stack Protector for Rust
• Give integer literals a sign instead of relying on negation expressions
• Also enable ICE file dumps on stable
• New Tier-3 target proposal: loongarch64-linux-android

No Items entered Final Comment Period this week for Cargo, Rust, 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

• Thin pointers with inline metadata

Tracking Issues & PRs

New and Updated RFCs

Upcoming Events

Rusty Events between 2025-12-31 - 2026-01-28 🦀

Virtual

• 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
• 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 (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday
• 2026-01-13 | Virtual | libp2p Events
  • rust-libp2p Open Maintainers Call
• 2026-01-13 | Virtual (Tel Aviv-yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Live Open Source Rust project contribution
• 2026-01-14 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-01-15 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 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

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
• 2026-01-07 | Girona, ES | Rust Girona
  • Rust Girona Hack & Learn 01 2026
• 2026-01-08 | Geneva, CH | Post Tenebras Lab
  • Rust Meetup Geneva
• 2026-01-14 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup
• 2026-01-20 | Leipzig, SN, DE | Rust - Modern Systems Programming in Leipzig
  • Topic TBD
• 2026-01-20 | Paris, FR | Rust Paris
  • Rust meetup #82

North America

• 2026-01-01 | Saint Louis, MO, US | STL Rust
  • Cancelled
• 2026-01-03 | Boston, MA, US | Boston Rust Meetup
  • Allston Rust Lunch, Jan 3
• 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
• 2026-01-10 | 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
• 2026-01-13 | Spokane, WA, US | Spokane Rust
  • .NET Conference 2025 Spokane
• 2026-01-15 | 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
• 2026-01-24 | 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

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

what even is time?!?

– Ralf Jung on his blog

Thanks to llogiq 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

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.

Want TWIR in your inbox? Subscribe here.

Updates from Rust Community

Official

• What do people love about Rust?
• Please submit 2026 Project goal proposals
• December 2025 Project Director Update
• Program management update — End of 2025
• Rustup 1.29.0 beta: Call for Testing!

Newsletters

• The Embedded Rustacean Issue #61
• Scientific Computing in Rust #13 (December 2025)

Project/Tooling Updates

• What's "new" in Miri (and also, there's a Miri paper!)
• cargo-coupling: Visualizing Coupling in Rust Projects
• Announcing Asterinas 0.17.0
• Tuitar - A portable guitar training tool & DIY kit
• Gitoxide in December
• Announcing GotaTun, the future of WireGuard at Mullvad VPN
• wgpu v28.0.0 - Mesh Shaders, Immediates, and More!
• rustc_codegen_gcc: Progress Report #39

Observations/Thoughts

• Syntactic musings on the fallibility effect
• Rust’s Block Pattern
• [audio] Netstack.FM episode 19 — Firezone and Zero-Trust Network Security with Thomas Eizinger

Rust Walkthroughs

• Rust Unit Testing: Basic HTTP Server
• Async Rust Bluetooth Plumbing: Where the Throughput Goes
• [series] Part 2: Tensor Operations, Building an LLM from Scratch in Rust

Crate of the Week

This week's crate is arcshift, an Arc replacement for read-heavy workloads that supports lock-free atomic replacement.

Thanks to rustkins 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, 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 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

475 pull requests were merged in the last week

Compiler

• add target_feature = "gc" for Wasm
• better closure requirement propagation
• correctly encode doc attribute metadata
• don't treat asserts as a call in cross-crate inlining
• improve filenames encoding and misc
• make closure capturing have consistent and correct behaviour around patterns
• support recursive delegation

Library

• add try_as_dyn and try_as_dyn_mut
• add const default for OnceCell and OnceLock
• expand str_as_str to more types
• make const BorrowMut require const Borrow and make const Fn require const FnMut
• hashbrown: add hash_map::{OccupiedEntry::into_entry, VacantEntryRef::insert_entry_with_key}, make EntryRef use ToOwned again
• hashbrown: add hash_table::OccupiedEntry::replace_entry_with to mirror HashMap API
• hashbrown: add hash_table::UnsafeIter, iter() method to various iterators

Rustdoc

• Add missing close tags in extern crate reexports
• Fix invalid handling of field followed by negated macro call
• generate macro expansion for rust compiler crates docs
• handle macro expansions in types

Clippy

• transmuting_null: Check const integer casts
• allow multiline suggestions in map-unwrap-or
• do not attempt to use nth with non-usize argument
• don't emit collapsible_else_if lint when all arms contain only if {} else {} expressions
• fix cmp_null missing parens in the example
• fix empty_enum_variants_with_brackets misses removing brackets in patterns
• fix if_then_some_else_none suggests wrongly when then ends with comment
• fix needless_type_cast suggesting invalid code for non-literal initializers
• fix println_empty_string suggestion caused error
• fix use_self false positive on type in const generics
• fix an incorrect error message regarding the size of usize and isize in cast_precision_loss
• move collapsible_else_if to pedantic
• new lint - same_length_and_capacity

Rust-Analyzer

• add 'Use of AI tools' section to CONTRIBUTING.md
• add BreakExpr completion suggest
• add an lsp extension to get failed obligations for a given function
• add default varname for TryEnum postfix completion
• add guess braces doc T![] for T_
• add ide-assist: add_explicit_method_call_deref
• complete reference &T → &&T
• introduce crate_attrs field in rust-project.json
• pretty print attributes up to cfg(false)
• fix applicable on non naked if for move_guard assist
• fix guess renamed macro braces
• fix indent for convert_iter_for_each_to_for
• fix indent for merge_nested_if
• fix match arm nested body invalid expected type
• fix nested if-let for merge_nested_if
• fix flycheck generations not being synced for multiple workspaces
• more perf improvements, made possible after non-Salsa interneds
• non-Salsa-interned solver types - with GC for them
• remove conflicting advice
• support undotted-self for this param closure

Rust Compiler Performance Triage

Very quiet week, with essentially no change in performance.

Triage done by @simulacrum. Revision range: 21ff67df..e1212ea7

1 Regression, 1 Improvement, 3 Mixed; 2 of them in rollups 36 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.

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

• Explicitly export core and std macros
• Stabilize 29 RISC-V target features (riscv_ratified_v2)

Cargo

• feat(toml): TOML 1.1 parse support

Compiler Team (MCPs only)

• Allow combining --help -C help -Z help -W help in one invocation

Leadership Council

• Raise travel grant limit to $100,000 for 2026
• Fund program management program for 2026
• Raise automatic travel grant to $2000

No Items entered Final Comment Period this week for Rust RFCs, 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

• Thin pointers with inline metadata

Upcoming Events

Rusty Events between 2025-12-24 - 2026-01-21 🦀

Virtual

• 2025-12-30 | Virtual (Tel Aviv-yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Live Open Source Rust project contribution
• 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
• 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 (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday
• 2026-01-13 | Virtual | libp2p Events
  • rust-libp2p Open Maintainers Call
• 2026-01-15 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 2026-01-20 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2026-01-21 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Stack Safety

Asia

• 2026-01-07 | Tel Aviv-yafo, IL | Rust 🦀 TLV
  • In person Rust January 2026 at AWS in Tel Aviv

Europe

• 2026-01-07 | Amsterdam, NL | Rust Developers Amsterdam Group
  • Meetup @ Instruqt
• 2026-01-07 | Girona, ES | Rust Girona
  • Rust Girona Hack & Learn 01 2026
• 2026-01-08 | Geneva, CH | Post Tenebras Lab
  • Rust Meetup Geneva
• 2026-01-14 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup
• 2026-01-20 | Leipzig, SN, DE | Rust - Modern Systems Programming in Leipzig
  • Topic TBD
• 2026-01-20 | Paris, FR | Rust Paris
  • Rust meetup #82

North America

• 2025-12-27 | Boston, MA, US | Boston Rust Meetup
  • Lechmere Rust Lunch, Dec 27
• 2026-01-03 | Boston, MA, US | Boston Rust Meetup
  • Allston Rust Lunch, Jan 3
• 2026-01-08 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2026-01-10 | Boston, MA, US | Boston Rust Meetup
  • Central Cambridge Rust Lunch, Jan 10
• 2026-01-15 | 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
• 2026-01-20 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2026-01-21 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground

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

they should just rename unsafe to C so people can shut up

– /u/thisismyfavoritename on /r/rust

Thanks to Brian Kung 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

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.

Want TWIR in your inbox? Subscribe here.

Updates from Rust Community

Official

• Project goals update — November 2025 | Rust Blog
• Announcing Rust 1.92.0 | Rust Blog

Project/Tooling Updates

• How we made SeaORM synchronous
• Building Slatron: The Digital TV Scheduling and Automation System
• The state of the kernel Rust experiment

Observations/Thoughts

• Secure your Rust projects and improve the developer experience with Dev Containers
• Miri: Practical Undefined Behavior Detection for Rust
• Finding Alignment by Visualizing Music With Rust
• Rust GCC backend: Why and how

Rust Walkthroughs

• Rust Unit Testing: File writing
• Stop Losing Intent: Absent, Null, and Value in Rust
• Getting started: How to Learn Embedded Rust for Beginners
• Writing a mockable Filesystem trait in Rust without RefCell
• [series] The Impatient Programmer’s Guide to Bevy and Rust: Chapter 4 - Let There Be Collisions
• Building Secure OTA Updates for ESP32 Over BLE with Rust
• Positional Memoization via Proc Macros in a Rust UI Framework
• hotpath-rs - CPU time vs wall-clock time: profiling async Rust

Miscellaneous

• November '25 Jobs Report
• Supercharging Security Auditing with Rust: An Interview with Caido

Crate of the Week

This week's crate is logos, a modern lexer generator.

Thanks to Sam O'Brien for the (partial 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
• RustConf 2026 | CFP closes 2026-02-16 | Montreal, Quebec, Canada | 2026-09-08 - 2026-09-11

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

482 pull requests were merged in the last week

Compiler

• rustc_scalable_vector(N)
• experimentally add heterogeneous try blocks
• externally implementable items
• forbid freely casting lifetime bounds of dyn-types
• inherit attributes in delegation
• only resolve main in bin crates
• overhaul filename handling for cross-compiler consistency
• simplify how inline asm handles MaybeUninit

Library

• add SystemTime::{MIN, MAX}
• add core::hint::prefetch_{read, write}_{data, instruction}
• constify DropGuard::dismiss and trait impls
• fix vec iter zst alignment
• stabilize const_mul_add

Cargo

• feat(log): make timing messages ready for HTML replay
• feat(report): cargo report timings HTML replay
• new: Improve quality of package name error messages
• package: Don't verify registry for --list
• fix(timing): more self-contained timing/log data
• test(lint): redact more due to line got omitted
• cache submodule into git db
• downgrade curl-sys to 0.4.83
• feat: stabilize -Zconfig-include
• fixed incorrect locking logic when artifact-dir == build-dir
• test: use a larger default term width

Clippy

• format_push_string: give a (possibly incomplete) suggestion
• manual_saturating_arithmetic: lint x.checked_sub(y).unwrap_or_default()
• transmute_ptr_to_ref: Handle a pointer wrapped in a struct
• unnecessary_fold: lint on folds with Add::add/Mul::mul
• match_like_matches_macro: fix false positive with guards containing if let
• add needless_type_cast lint
• add iterator reduction coverage to never_loop
• count unsafe operations and macro calls once towards the innermost unsafe block
• do not look for disallowed methods inside desugared code
• fix branches-sharing-code suggests wrongly on const and static
• fix clippy::ref_as_ptr for non-temporary references in let/const
• fix if_not_else wrong unmangled macros
• fix if_then_some_else_none false positive when encountering await codes
• fix map_entry suggests wrongly for insert with cfg-ed out code
• fix match_like_matches_macro wrongly unmangled macros
• fix set-contains-or-insert false positive when set is mutated before insert
• fix unchecked_time_subtraction false negative on Ops::sub method call

Rust-Analyzer

• fix "Invariant violation: file emitted multiple times" when doing scip .
• fix bind_unused_param applicable on closure
• fix assist and → and_then parameter
• fix complete reference for &mut ty → &ty
• fix complete unit return semicolon in arg-list
• fix expected type no strip deref
• fix indent for toggle_ignore
• fix invalid logic op for replace_let_with_if_let
• fix loses label for convert_for_to_while_let
• fix not applicable fn in closure for add_return_type
• #[rustc_deprecated_safe_2024] can also come as #[rustc_deprecated_safe_2024(audit_that = "reason")]
• is_transmutable always panicking
• fix a panic in ast::TypeBound::kind()
• fix method resolution for incoherent impls when there are two sysroots in the crate graph
• implementation of locals_used in HIR level
• lsp: handle dynamic registration for didSave
• prefix json target file with workspace root for sysroot metadata
• respect rustc's lint attribute application order
• show parameter hint for missing arguments
• support #[feature(associated_type_defaults)]
• support dyn compatibility for old toolchains without MetaSized
• support the new lowering of format_args!()
• use cmark_with_options to write shortcuts links to the output
• include operator overload occurrences in SCIP index
• reorder add_return_type assist

Rust Compiler Performance Triage

This week we saw several regressions, partly from the compiler doing more work. The remaining regressions are being investigated.

Triage done by @kobzol. Revision range: 55495234..21ff67df

Summary:

3 Regressions, 2 Improvements, 5 Mixed; 2 of them in rollups 36 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: * Adding a crates.io Security tab

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

• Don't strip shebang in expr-ctxt include!(…)
• Policy on the use of rustc_legacy_const_generics in stdarch
• Tracking Issue for atomic_try_update

Rust RFCs

• build-std: context

Cargo

• feat(index): Stabilize pubtime

Leadership Council

• Add alumni policy

No Items entered Final Comment Period this week for Compiler Team (MCPs only), 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: Open up your enum with an unnamed variant

Upcoming Events

Rusty Events between 2025-12-17 - 2026-01-14 🦀

Virtual

• 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
• 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 (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday

Asia

• 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

• 2025-12-18 | London, UK | London Rust Project Group
  • gcc backend
• 2025-12-19 | Lyon, FR | Rust Lyon
  • Rust Lyon Meetup #11
• 2026-01-07 | Girona, ES | Rust Girona
  • Rust Girona Hack & Learn 01 2026
• 2026-01-08 | Geneva, CH | Post Tenebras Lab
  • Rust Meetup Geneva
• 2026-01-14 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup

North America

• 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
• 2025-12-25 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2026-01-08 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO

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 allow my code to be used for training AI on GitHub. Not because I fear AI taking our jobs—but because I’m confident my code will slow it down enough to save us all.

– 王翼翔 on rust-users

Thanks to Moy2010 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