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

• Rust 2024 call for testing

Newsletters

• The Embedded Rustacean Issue #33

Project/Tooling Updates

• Announcing Nio: an async runtime for Rust
• Announcing rust-query
• "pigg" (the Raspberry Pi GPIO GUI) 0.5.0 release, now with Pi Pico W support via rust and embassy
• Hello flourish! - Intuitive signals in Rust
• Ferrocene 24.11.0 with medical and QNX qualification now available!

Observations/Thoughts

• A Novel Idea About Functor In Rust?
• Optimizing a Rust GPU matmul kernel
• Map Keys and Lifetimes
• Rustlantis: Randomized Differential Testing of the Rust Compiler
• Undroppable Types
• 40-year-old hacker group prefers Rust
• Cursed Linear Types In Rust
• Unsafe for work
• Aligning with rust's Guiding Principle: my path to finding my 'Why'

Rust Walkthroughs

• [video] Build with Naz - TLS in Rust with tokio, rustls, CFSSL
• Optimization adventures: making a parallel Rust workload 10x faster with (or without) Rayon
• Building Thread-safe Async Primitives in 150 lines of Rust
• Securely sending DHT22 sensor data from an ESP32 board to PostgreSQL
• Writing a mark-and-sweep tracing GC in Rust

Miscellaneous

• Making Rust a first class citizen for Xen

Crate of the Week

This week's crate is postcard, a battle-tested, well-documented #[no_std] compatible serializer/deserializer geared towards use in embedded devices.

Thanks to Reto Trappitsch 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.

RFCs

Rust

Rustup

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.

• Diesel - Add support for currently unsupported postgres json/jsonb functions
• Diesel - Add missing sqlite json/jsonb functions and operators

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.

• Rust in Paris 2025 | Deadline: 30 November 2024 | Paris, FR | 15 March 2025

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!

• FOSDEM 2025 Rust devroom | Deadline: 1 December 2024 | Brussels, BE | 1 February 2025

Updates from the Rust Project

405 pull requests were merged in the last week

• lints_that_dont_need_to_run: never skip future-compat-reported lints
• aarch64 softfloat target: always pass floats in int registers
• account for wasm32v1-none when exporting TLS symbols
• add visit methods to ast nodes that already have walks on ast visitors
• add specific diagnostic for using macro_rules macro as attribute/derive
• add visits to nodes that already have flat_maps in ast::MutVisitor
• allow disabling ASan instrumentation for globals
• bail in effects in old solver if self ty is ty var
• btree: don't leak value if destructor of key panics
• constify the Deref/DerefMut traits, too
• continue ParamEnv to TypingEnv transition
• correct the tier listing of wasm32-wasip2
• default-enable llvm_tools_enabled when no config.toml is present
• distinguish overflow and unimplemented in Step::steps_between
• don't allow -Zunstable-options to take a value
• drop debug info instead of panicking if we exceed LLVM's capability to represent it
• emscripten: link with -sWASM_BIGINT
• fix LLVM target triple for x86_64-win7-windows-msvc
• fix asm goto with outputs and move it to a separate feature gate
• fix closure arg extraction in extract_callable_info, generalize it to async closures
• implement ~const Destruct effect goal in the new solver
• implement ~const Fn trait goal in the new solver
• implement ~const item bounds in RPIT
• implement the unsafe-fields RFC
• make PointerLike opt-in instead of built-in
• make asm label blocks safe context
• merge -Zhir-stats into -Zinput-stats
• point at const definition when used instead of a binding in a let statement
• pretty print async fn sugar in opaques and trait bounds
• reduce false positives of tail-expr-drop-order from consumed values (attempt #2)
• refactor where predicates, and reserve for attributes support
• remove is_trivially_const_drop
• remove legacy bitcode for iOS
• report the unexpected_cfgs lint in external macros
• rustc: fail fast when compiling a source file larger than 4 GiB
• show abi_unsupported_vector_types lint in future breakage reports
• stop being so bail-y in candidate assembly
• store resolution for self and crate root module segments
• unstable feature usage metrics
• use ConstArgKind::Path for all single-segment paths, not just params under min_generic_const_args
• use confstr(_CS_DARWIN_USER_TEMP_DIR, ...) as a TMPDIR fallback on Darwin
• use arc4random of libc for RTEMS target
• use attributes for dangling_pointers_from_temporaries lint
• interpret: do not ICE when a promoted fails with OOM
• miri: added epoll and eventfd for Android
• miri: eventfd: comment tweaks
• miri: fill out windows io error mapping table
• miri: follow-up on #4052, making a miri evaluation context fn for strerror_r
• miri: implement square root without relying on host floats
• miri: refactor AnonSocket::read/write for blocking socketpair
• miri: simplify thread blocking tests
• miri: sysconf adding few more constants
• miri: sysconf interception fix for solarish systems
• miri: trophy case: add RwLock::downgrade bug
• miri: use PathBuf APIs to correctly do some path manipulation cross-platform
• resolve tweaks
• finish Reveal removal
• stabilize the 2024 edition
• stabilize Ipv6Addr::is_unique_local and Ipv6Addr::is_unicast_link_local
• stabilize const_float_methods
• stabilize const_pin_2
• minimally constify Add
• mark <[T; N]>::as_mut_slice with the const specifier
• mark get_mut and set_position in std::io::Cursor as const
• reduce integer Display implementation size
• std: allow after-main use of synchronization primitives
• implement OsString::truncate
• add AsyncFn* to the prelude in all editions
• add BorrowedBuf::into_filled{,_mut} methods to allow returning buffer with original lifetime
• add std::thread::add_spawn_hook
• add vec_deque::Iter::as_slices and friends
• support each_ref and each_mut in [T; N] in constant expressions
• support input/output in vector registers of s390x inline assembly (under asm_experimental_reg feature)
• support s390x z13 vector ABI
• uefi: process: add args support
• hashbrown: release v0.15.2
• cargo: test(rustflags): Verify -Cmetadata directly, not through -Cextra-filename
• cargo: allow registries to omit empty/default fields in JSON
• cargo: check build target supports std when building with -Zbuild-std=std
• cargo: docs for optional registry JSON fields
• cargo: feat: stabilize Edition 2024
• cargo: improve error handling when PathSource is relative
• cargo: test: address test output nondeterminism
• cargo: test: switch from 'exec_with_output' to 'run'
• rustdoc: do not call to_string, it's already impl Display
• bindgen: add raw_ref_macros feature
• clippy: add new lint doc_include_without_cfg
• clippy: add note about caveat for cfg(doc)
• clippy: don't consider lifetimes in bounded types unused (fix extra_unused_lifetimes FP)
• clippy: sync and Release automation
• clippy: use a better message for unnecessary_map_or lint
• rust-analyzer: convert add_braces to SyntaxFactory SyntaxEditor abstraction
• rust-analyzer: use snippet placeholders for generated match arms
• rust-analyzer: fix a stack overflow when computing the sizedness of a struct that includes itself as the tail field
• rust-analyzer: improve selection handling for the merge_match_arms assist
• rust-analyzer: migrate reorder_impl_items Assist to Use SyntaxFactory

Rust Compiler Performance Triage

This week saw more regressions than improvements, mostly due to three PRs that performed internal refactorings that are necessary for further development and modification of the compiler.

Triage done by @kobzol. Revision range: 7d40450b..7db7489f

Summary:

4 Regressions, 2 Improvements, 3 Mixed; 3 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:

• 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.

RFCs

• [disposition: merge] [RFC] Explicit ABI in extern

Tracking Issues & PRs

Rust

• [disposition: merge] Tracking Issue for sub_ptr (feature ptr_sub_ptr)
• [disposition: merge] Stabilize unsigned and float variants of ｀num_midpoint｀ feature
• [disposition: merge] Tracking issue for Vec::extract_if and LinkedList::extract_if
• [disposition: merge] Stabilize noop_waker
• [disposition: merge] Stabilize const_maybe_uninit_write
• [disposition: merge] Tracking Issue for Path::file_prefix
• [disposition: merge] Stabilize ｀#[diagnostic::do_not_recommend]｀
• [disposition: merge] Make missing_abi lint warn-by-default.
• [disposition: merge] Tracking Issue for ptr::fn_addr_eq
• [disposition: merge] Fix and undeprecate home_dir()

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

• [new] crates.io: Remove version deletions from the "crate deletions" RFC
• [new] RFC: Add a semantically non-blocking lint level

Upcoming Events

Rusty Events between 2024-11-27 - 2024-12-25 🦀

Virtual

• 2024-11-28 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-11-28 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2024-11-29 | Virtual (Jersey City, NJ, US)| Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2024-12-02 | Virtual (London, UK) | Women in Rust
  • Advent of Code - Kick Off!
• 2024-12-03 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group
• 2024-12-03 | Virtual (San Francisco, CA, US) | Blockchain Center SF
  • Rust in Web3: Developer Series
• 2024-12-04 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2024-12-05 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-12-05 | Virtual (Miami, FL) | Miami Java User Group Events
  • Introduction to Rust for Java Developers
• 2024-12-06 | Virtual (Jersey City, NJ, US)| Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2024-12-07 | Virtual (Kampala, UG) | Rust Circle Kampala
  • Rust Circle Meetup
• 2024-12-08 | Virtual (Tel Aviv-Yafo, IL) | Rust 🦀 TLV
  • Reading JSON files in Rust - קריאת קבצי ג'ייסון בראסט
• 2024-12-10 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2024-12-11 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2024-12-12 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-12-12 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2024-12-12 | Hybrid: In-Person and Virtual (Seattle, WA, US) | Seattle Rust Meetup
  • December Meetup
• 2024-12-13 | Virtual (Jersey City, NJ, US)| Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2024-12-17 | Virtual (San Francisco, CA, US) | Blockchain Center SF
  • Rust in Web3: Developer Series
• 2024-12-17 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2024-12-19 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-12-19 | Virtual (Mexico City, DF, MX) | Rust MX
  • Posada 2024
• 2024-12-20 | Virtual (Jersey City, NJ, US)| Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2024-12-24 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday

Africa

• 2024-12-10 | Johannesburg, ZA | Johannesburg Rust Meetup
  • Hello World... again

Asia

• 2024-11-28 | Bangalore/Bengaluru, IN | Rust Bangalore
  • RustTechX Summit 2024 BOSCH
• 2024-11-30 | Tokyo, JP | Rust Tokyo
  • Rust.Tokyo 2024
• 2024-12-03 | Ra'anana, IL | Abra R&D Meetups
  • Rust in the Linux Kernel

Europe

• 2024-11-27 | Dortmund, DE | Rust Dortmund
  • Rust Dortmund
• 2024-11-28 | Aarhus, DK | Rust Aarhus
  • Talk Night at Lind Capital
• 2024-11-28 | Augsburg, DE | Rust Meetup Augsburg
  • Augsburg Rust Meetup #10
• 2024-11-28 | Berlin, DE | OpenTechSchool Berlin + Rust Berlin
  • Rust and Tell - Title
• 2024-11-28 | Copenhagen, DK | Copenhagen Rust Community
  • Rust meetup #53 sponsored by Microsoft
• 2024-11-28 | Gdansk, PL | Rust Gdansk
  • Rust Gdansk Meetup #5
• 2024-11-28 | Hamburg, DE | Rust Meetup Hamburg
  • Rust Hack & Learn with Mainmatter & Otto
• 2024-11-28 | Manchester, UK | Rust Manchester
  • Rust Manchester November Code Night
• 2024-11-28 | Prague, CZ | Rust Prague
  • Rust/C++ Meetup Prague (November 2024)
• 2024-11-30 | Stockholm, SE | Stockholm Rust
  • Ferris' Fika Forum #7
• 2024-12-03 | Copenhagen, DK | Copenhagen Rust Community
  • Rust Hack Night #11: Advent of Code
• 2024-12-04 | Girona, ES | Rust Girona
  • Aprenem junts Rust / Learn Rust Together
• 2024-12-04 | Köln, DE | Rust Cologne
  • Rust in December: Advent of Code
• 2024-12-04 | Oxford, UK | Oxford Rust Meetup Group
  • Oxford Rust and C++ social
• 2024-12-04 | Paris, FR | Rust Paris
  • Rust meetup #73
• 2024-12-05 | Gdansk, PL | Rust Gdansk
  • Rust Gdansk Meetup #6
• 2024-12-05 | Zlin, CZ | Rust Moravia
  • Rust Moravia Meetup (December 2024)
• 2024-12-06 | Moscow, RU | RustCon RU
  • RustCon Russia
• 2024-12-11 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup
• 2024-12-12 | Amsterdam, NL | Rust Developers Amsterdam Group
  • Rust Meetup @ JetBrains
• 2024-12-17 | Leipzig, DE | Rust - Modern Systems Programming in Leipzig
  • Types, Traits und Best Practices

North America

• 2024-11-27 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2024-12-05 | Montréal, QC, CA | Rust Montréal
  • December Monthly Social
• 2024-12-05 | St. Louis, MO, US | STL Rust
  • Rust Strings
• 2024-12-10 | Ann Arbor, MI, US | Detroit Rust
  • Rust Community Meetup - Ann Arbor
• 2024-12-12 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2024-12-12 | Hybrid: In-Person and Virtual (Seattle, WA, US) | Seattle Rust User Group
  • December Meetup
• 2024-12-16 | Minneapolis, MN, US | Minneapolis Rust Meetup
  • Minneapolis Rust Meetup Happy Hour
• 2024-12-17 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2024-12-23 | Ferndale, MI, US | Detroit Rust
  • Rust Community Meetup - Ferndale

Oceania

• 2024-12-04 | Sydney, AU | Rust Sydney
  • 2024 🦀 Encore ✨ Talks
• 2024-12-08 | Canberra, AU | Canberra Rust User Group
  • CRUG Xmas party

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

Will never stop being positively surprised by clippy

text error: hypothenuse can be computed more accurately: --> src/main.rs:835:5 | 835 | (width * width + height * height).sqrt() / diag | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `width.hypot(height)` | help: for further information, visit https://rust-lang.github.io/rust-clippy/master/index.html#imprecise_flops

• Manos Pitsidianakis (and rust-clippy) on Mastodon

llogiq is quite self-appreciative regarding his 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, bennyvasquez.

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Discuss on r/rust