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 on X (formerly Twitter) 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: 1.85

Newsletters

• The Embedded Rustacean Issue #37

Project/Tooling Updates

• gitoxide - January 2025
• musi lili 0.2 released

Observations/Thoughts

• Comparing Rust Actor Libraries: Actix, Coerce, Kameo, Ractor, and Xtra
• Improve Rust Compile Time by 108X
• Branchless UTF-8 Encoding
• The hunt for error -22
• Automatic Server Reloading in Rust on Change: What is listenfd/systemfd?
• Investigating a Strange Out-of-Memory Error
• Comparing 13 Rust Crates for Extracting Text from HTML
• Typesafe Frontend Routing in Rust/Leptos
• Interview with passionate Rust Developer Radu Marias
• Introducing RealtimeSanitizer for Rust
• The HARM Stack (HTMX, Axum/AlpineJS, Rust, Maud) Considered Unharmful
• Type Inference in Rust and C++
• Path canonicalization is unergonomic
• [video] Rust is not Complicated - An architects perspective

Rust Walkthroughs

• A Gentle Introduction to WebAssembly in Rust (2025 Edition)
• Adding A New Fake To The Fake Crate
• Streaming Audio Apis: The Axum Server
• Prototyping in Rust

Miscellaneous

• 2024 in review - seanmonstar
• "We never update unless forced to" — cargo-semver-checks 2024 Year in Review
• Year in review: 2024 highlights and a peek at 2025 - Graphite
• Why Rust is not a functional language
• How I think about Zig and Rust
• [video] Breaking Rust’s memory safety with 1 line of code
• [audio] Crates We Love | Oxide and Friends

Crate of the Week

This week's crate is resvg, an SVG rendering library.

Thanks to David Mason 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. The following RFCs would benefit from user testing before moving forward:

RFCs

• No calls for testing were issued this week.

Rust

• No calls for testing were issued this week.

Rustup

• No calls for testing were issued 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.

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.

• rama - first version of rama-unix
• rama - add web Router service to rama-http
• rama - add full-stack rama benchmarks
• rama - add rama to "the-benchmarker"
• rama - add rama server benchmark to sharkbench
• rama - add rama to TechEmpower's FrameworkBenchmark

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.

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

397 pull requests were merged in the last week

• cfg_match: Adjust syntax
• rustc_resolve: use structured fields in traces
• add Profile Override for Non-Git Sources
• add cache to AmbiguityCausesVisitor
• add gpu-kernel calling convention
• add license-metadata.json to rustc-src tarball
• allow coercing safe-to-call target_feature functions to safe fn pointers
• always force non-trimming of path in unreachable_patterns lint
• cleanup promoteds move check
• consider more erroneous layouts as LayoutError::ReferencesError to suppress spurious errors
• consolidate ad-hoc MIR lints into real pass-manager-based MIR lints
• const traits: remove some known-bug that do not seem to make sense
• const-eval: detect more pointers as definitely not-null
• convert struct FromBytesWithNulError into enum
• coverage: completely overhaul counter assignment, using node-flow graphs
• detect if-else chains with a missing final else in type errors
• disallow A { .. } if A has no fields
• do not consider traits that have unsatisfied const conditions to be conditionally const
• don't skip argument parsing when running rustc with no arguments
• eagerly mono drop for structs with lifetimes
• encode constraints that hold at all points as logical edges in location-sensitive polonius
• enforce syntactical stability of const traits in HIR
• fix ICE in resolving associated items as non-bindings
• fix overflows in the implementation of overflowing_literals lint's help
• fix suggestion to convert dereference of raw pointer to ref
• for purely return-type based searches, deprioritize clone-like functions
• fully de-stabilize all custom inner attributes
• further improve panic_immediate_abort by removing rtprintpanic! messages
• implement use associated items of traits
• improve DispatchFromDyn and CoerceUnsized impl validation
• leak check in impossible_predicates to avoid monomorphizing impossible instances
• location-sensitive polonius prototype: endgame
• make missing_abi lint warn-by-default
• make sure to scrape region constraints from deeply normalizing type outlives assumptions in borrowck
• make sure we actually use the right trivial lifetime substs when eagerly monomorphizing drop for ADTs
• make sure we can produce ConstArgHasWrongType errors for valtree consts
• methods of const traits are const
• mir borrowck: cleanup late-bound region handling
• new solver: prefer trivial builtin impls
• only treat plain literal patterns as short
• outline panicking code for LocalKey::with
• Replace extern "rust-intrinsic" with #[rustc_intrinsic] across the codebase
• prefer lower TraitUpcasting candidates in selection
• provide structured suggestion for #![feature(..)] in more cases
• reexport likely/unlikely in std::hint
• respect --sysroot for rustc -vV and -Cpasses=list
• stable Hash: Ignore all HirIds that just identify the node itself
• treat other items as functions for the purpose of type-based search
• treat safe target_feature functions as unsafe by default (less invasive variant)
• use a C-safe return type for __rust_[ui]128_* overflowing intrinsics
• use indirect return for i128 and f128 on wasm32
• use trait definition cycle detection for trait alias definitions, too
• when LLVM's location discriminator value limit is exceeded, emit locations with dummy spans instead of dropping them entirely
• use a C-safe return type for __rust_[ui]128_* overflowing intrinsics
• stabilize float_next_up_down
• std: lazily allocate the main thread handle
• made Path::name only have item name rather than full name
• move std::pipe::* into std::io
• less unsafe in dangling/without_provenance
• cargo: created a function for user defined aliases
• cargo: fix benchsuite issue with newer versions of git
• cargo: fix: wrong concat and field name
• cargo: took the functionality of the third party subcommand from the list_commands function
• rustdoc: remove AttributesExt trait magic that added needless complexity
• rustdoc: Replace module list items ul/li with dl/dd/dt elements
• clippy: add a new lint for repeat().take() that can be replaced with repeat_n()
• clippy: change literal_string_with_formatting_args lint category to nursery
• clippy: emit missing_const_for_fn for CONST_MUT_REFS
• clippy: fix: correct suggestion for significant_drop_in_scrutinee in expressions
• clippy: new lint useless-nonzero-new_unchecked
• clippy: new lint: unnecessary_semicolon
• clippy: rust 1.81 and later support elision with explicit self types
• clippy: suggest manual_div_ceil even when right operand is a constant
• clippy: use clearer multipart suggestions for unnecessary_map_or lint
• rust-analyzer: add missing #[rust_analyzer::rust_fixture] annotations
• rust-analyzer: add missing Win32_Foundation feature
• rust-analyzer: extract variable assist triggers less eagerly
• rust-analyzer: add dereferencing autocomplete
• rust-analyzer: add smart completions that skip await or iter() and into_iter()
• rust-analyzer: add the ability to jump from into to from definitions
• rust-analyzer: complete raw, const keyword
• rust-analyzer: render type parameter projection target bounds in inlays
• rust-analyzer: show go-to-type-def actions for func param and trait bound when hovering
• rust-analyzer: cargo rustc --print needs unstable-options
• rust-analyzer: detect missing errors for } braces before else in let...else statements
• rust-analyzer: don't return inlay hints outside requested range
• rust-analyzer: fix a bug where enum variants were not considered properly in type ns resolution
• rust-analyzer: fix another bug when reaching macro expansion limit caused a stack overflow
• rust-analyzer: fix missing upmapping in trait impls completion
• rust-analyzer: fix semantics not always correctly caching file roots
• rust-analyzer: make test_runner::TestState::stdout optional to fix parsing cargo test json output
• rust-analyzer: flip on typing config to be opt-in, better defaults
• rust-analyzer: generalize some type walking in hover type actions
• rust-analyzer: lsp-server: drop outgoing messages on background thread
• rust-analyzer: proc-macro-srv: make usage of RTLD_DEEPBIND portable
• rust-analyzer: properly record meaningful imports as re-exports in symbol index

Rust Compiler Performance Triage

A very quiet week for performance, with small improvements essentially on all benchmarks.

Triage done by @simulacrum. Revision range: 1ab85fbd..9a1d156f

0 Regression, 1 Improvement, 2 Mixed; 0 of them in rollups 40 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:

• Supertrait item shadowing v2

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.

RFCs

• [RFC] Target Modifiers

Tracking Issues & PRs

Rust

• remove long-deprecated no-op attributes no_start and crate_id
• Stabilize target_feature_11
• Add File already exists error doc to hard_link function
• Tracking Issue for once_wait
• fix(libtest): Deprecate '--logfile'
• Windows: remove readonly files
• make rustc_encodable_decodable feature properly unstable

Cargo

• No Cargo Tracking Issues or PRs entered Final Comment Period this week.

Language Team

• No Language Team Proposals entered Final Comment Period this week.

Language Reference

• No Language Reference RFCs entered Final Comment Period this week.

Unsafe Code Guidelines

• No Unsafe Code Guideline Tracking Issues or PRs entered Final Comment Period this week.

New and Updated RFCs

• RFC: project goals for 2025h1

Upcoming Events

Rusty Events between 2025-01-22 - 2025-02-19 🦀

Virtual

• 2025-01-22 | Virtual (Rotterdam, NL) | Bevy Game Development
  • Bevy Meetup #8
• 2025-01-23 & 2025-01-24 | Virtual | Mainmatter Rust Workshop
  • Remote Workshop: Testing for Rust projects – going beyond the basics
• 2025-01-24 | Virtual (Jersey City, NJ, US) | Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2025-01-26 | Virtual (Tel Aviv-Yafo, IL) | Rust 🦀 TLV
  • Rust and embedded programming with Leon Vak (online in Hebrew)
• 2025-01-27 | Virtual (London, UK) | London Rust Project Group
  • using traits in Rust for flexibility, mocking/ unit testing, and more
• 2025-01-28 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Last Tuesday
• 2025-01-30 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2025-01-30 | Virtual (Charlottesville, VA, US) | Charlottesville Rust Meetup
  • Quantum Computers Can’t Rust-Proof This!
• 2025-01-30 | Virtual (Tel Aviv-Yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Are We Embedded Yet? - Implementing tiny HTTP server on a microcontroller
• 2025-01-31 | Virtual (Delhi, IN) | Hackathon Raptors Association
  • Blazingly Fast Rust Hackathon
• 2025-01-31 | Virtual (Jersey City, NJ, US) | Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2025-02-01 | Virtual (Kampala, UG) | Rust Circle Kampala
  • Rust Circle Meetup
• 2025-02-04 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group
• 2025-02-04 | Virtual (London, GB) | Women in Rust
  • Lunch & Learn: Rust Nation UK Talks
• 2025-02-05 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2025-02-07 | Virtual (Jersey City, NJ, US) | Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2025-02-11 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday
• 2025-02-11 | Virtual (Tel Aviv-Yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Meet Elusion: New DataFrame Library powered by Rust 🦀 with Borivoj Grujicic
• 2025-02-13 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 2025-02-18 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2025-02-19 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Pointer Provenance

Europe

• 2025-01-22 | London, GB | Rust London User Group
  • Rust London's New Years Party & Community Swag Drop
• 2025-01-22 | Oberursel, DE | Rust Rhein Main
  • Rust 2024 Edition and Beyond
• 2025-01-23 | Barcelona, ES | Barcelona Free Software
  • Why Build a New Browser Engine in Rust?
• 2025-01-23 | Paris, FR | Rust Paris
  • Rust meetup #74
• 2025-01-24 | Edinburgh, GB | Rust and Friends
  • Rust and Friends (daytime coffee)
• 2025-01-27 | Prague, CZ | Rust Prague
  • Rust Meetup Prague (January 2025)
• 2025-01-27 | Zagreb, HR | impl Zagreb for Rust
  • Meetup 2025/01: Optimizacija buildanja C++ i usporedba s Rustom (GUI alat)
• 2025-01-28 | Aarhus, DK | Rust Aarhus
  • Hack Night - Advent of Code
• 2025-01-28 | Manchester, GB | Rust Manchester
  • Rust Manchester January Code Night
• 2025-01-28 | Warsaw, PL | Rust Warsaw
  • Rust Warsaw Meetup #4
• 2025-01-30 | Augsburg, DE | Rust Meetup Augsburg
  • Rust Meetup #11: Hypermedia-driven development in Rust
• 2025-01-30 | Berlin, DE | Rust Berlin
  • Rust and Tell - Title
• 2025-01-30 | Copenhagen, DK | Copenhagen Rust Community
  • Rust meetup #54 sponsored by Google
• 2025-02-01 | Brussels, BE | FOSDEM 2025
  • FOSDEM Rust Devroom
• 2025-02-01 | Helsinki, FI | Finland Rust-lang Group
  • February Meetup
• 2025-02-01 | Nürnberg, DE | Rust Nuremberg
  • Technikmuseum Sinsheim
• 2025-02-05 | Oxford, GB | Oxford Rust Meetup Group
  • Oxford Rust and C++ social
• 2025-02-06 | Gdansk, PL | Rust Gdansk
  • Rust Gdansk Meetup #7
• 2025-02-12 | Reading, GB | Reading Rust Workshop
  • Reading Rust Meetup
• 2025-02-18 | Leipzig, SN, DE | Rust - Modern Systems Programming in Leipzig
  • Introduction to Context-Generic Programming in Rust
• 2025-02-19 - 2025-02-20 | London, UK | Rust Nation UK
  • Rust Nation UK 2025

North America

• 2025-01-22 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2025-01-23 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO | Rust Meetup at Hacker Dojo - Mountain View Rust Meetup Page
• 2025-01-28 | Boulder, CO, US | Boulder Rust Meetup
  • From Basics to Advanced: Testing
• 2025-02-06 | Mountain view, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2025-02-06 | Saint Louis, MO, US | STL Rust
  • Async, the Future of Futures
• 2025-02-11 | Minneapolis, MN, US | Minneapolis Rust Meetup
  • Minneapolis Rust Meetup Happy Hour
• 2025-02-18 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person

Oceania

• 2025-02-04 | Auckland, NZ | Rust AKL
  • Rust AKL: How We Learn 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

Memory safety issues mean you can’t trust what you’re seeing in your source code anymore.

– Someone from Antithesis on the shuttle blog

Thanks to scottmcm for the suggestion!

Please submit quotes and vote for next week!

This Week in Rust is edited by: nellshamrell, llogiq, cdmistman, ericseppanen, extrawurst, U007D, joelmarcey, mariannegoldin, bennyvasquez, bdillo

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust