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 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.

Updates from Rust Community

Official

Foundation

• Q3 2023 Recap from Rebecca Rumbul

Newsletters

• This Month in Rust OSDev: September 2023

Project/Tooling Updates

• Announcing EtherCrab, a Rust implementation of the EtherCAT industrial automation protocol
• rust-analyzer changelog #203

Observations/Thoughts

• Why async Rust?
• Compile Times and Code Graphs
• Containerize Rust applications on Ubuntu & Alpine, with GitHub Actions

Rust Walkthroughs

• A type level contains operation for heterogeneous list using associated types
• Using GraphQL in Rust
• Writing parsers in Winnow

Research

• Yuga: Automatically Detecting Lifetime Annotation Bugs in the Rust Language
• Fast Summary-based Whole-program Analysis to Identify Unsafe Memory Accesses in Rust

Miscellaneous

• Eurorust reflections
• EuroRust 2023 Reflections: What's a Conference For?
• [audio] RustShip: Graphite - Raster and Vector Graphics in Rust

Crate of the Week

This week's crate is rinf, a library to write Rust in Flutter.

Thanks to Kim Dong-Hyun for the self-suggestion!

Please submit your suggestions and votes for next week!

Call for Participation

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.

• Hyperswitch (Hacktoberfest) - [OpenNode] Currency Unit Conversion
• Hyperswitch (Hacktoberfest) - [Stax] Currency Unit Conversion
• Hyperswitch (Hacktoberfest) - [ACI] Currency Unit Conversion
• Ockam - Make ockam space show (no args) interactive by asking the user to choose from a list of space names to show (tuify)
• Ockam - Improve ockam tcp-inlet delete --help text (clap command)
• Ockam - Enroll "email: '+' character not allowed"

If you are a Rust project owner and are looking for contributors, please submit tasks here.

Updates from the Rust Project

409 pull requests were merged in the last week

• const_eval: allow function pointer signatures containing &mut T in const contexts
• rustc_hir_pretty cleanups
• add Config::hash_untracked_state callback
• add the V (vector) extension to the riscv64-linux-android target spec
• also consider call and yield as MIR SSA
• broaden the consequences of recursive TLS initialization
• cleanup rustc_features some more
• compute NLL loan scopes using the polonius model
• const-eval: allow calling functions with targat features disabled at compile time in WASM
• const-eval: make misalignment a hard error
• coverage: separate initial span extraction from span processing
• detect ruby-style closure in parser
• do not check for impossible predicates in const-prop lint
• don't UB on dangling ptr deref, instead check inbounds on projections
• exhaustiveness: rework constructor splitting
• explicitly handle auto trait leakage in coherence
• fix exit status / wait status on non-Unix cfg(unix) platforms
• fix overflow checking in range patterns
• handle several #[diagnostic::on_unimplemented] attributes correctly
• implement -Clink-self-contained=-linker opt out
• improve check-cfg diagnostics
• improve handling of assertion failures with very long conditions
• in smir use FxIndexMap to store indexed ids
• linker: also pass debuginfo compression flags
• make "request changes" reviews apply S-waiting-on-author
• on type error involving closure, avoid ICE
• on type error of closure call argument, point at earlier calls that affected inference
• opt-dist: disable unused features for tabled crate
• pass rustc shim flags using environment variable
• prevent more spurious unreachable pattern lints
• prevent showing methods from blanket impls of not available foreign traits to show up in the search results
• prevent spurious unreachable pattern lints
• relate alias ty with variance
• remove DefiningAnchor::Bubble from opaque wf check
• show enum discriminant if a compatible repr is used
• stabilize async fn and return-position impl Trait in trait
• structurally normalize for closure
• suggest adding return if the for semi which can coerce to the fn return type
• suggest labeling block if break is in bare block
• suggest trait bounds for used associated type on type param
• support AIX in Rust standard library
• use PatKind::Error when an ADT const value has violation
• use env variable to control thread ids in rustc_log
• add ability to get lines/filename for Span in smir
• miri: implement llvm.x86.sse41.* intrinsics
• miri: make NaN generation non-deterministic
• copy 1-element arrays as scalars, not vectors
• optimize librustc_driver.so with BOLT
• optimize file read in Config::verify
• optimize zipping over array iterators
• stabilize atomic_from_ptr
• stabilize const_maybe_uninit_assume_init_read
• stabilize {IpAddr, Ipv6Addr}::to_canonical
• impl Not, Bit{And,Or}{,Assign} for IP addresses
• impl Default for ExitCode
• add invariant to Vec::pop that len < cap if pop successful
• implement BufRead for VecDeque<u8>
• implement OnceCell/Lock::try_insert()
• implement slice::split_once and slice::rsplit_once
• add explicit-endian String::from_utf16 variants
• implement FusedIterator for DecodeUtf16 when the inner iterator does
• implement sys::args for UEFI
• inline Bytes::next and Bytes::size_hint
• make try_exists return Ok(true) for Windows Unix Sockets
• mark new_in as const for BTree collections
• regex-automata/meta: revert broadening of reverse suffix optimization
• regex-lite: tweak nest limit on stack overflow test
• regex: loosen ASCII compatible rules + improve reverse suffix optimization
• regex, regex-automata: fix compilation of doctests on 32-bit architectures
• regex-lite: fix compilation of doctests on 32-bit architectures
• regex: revert recent regex-syntax interval set optimizations
• cargo: fix(install): Suggest an alternative version on MSRV failure
• cargo: add detailed message when target folder path is invalid
• cargo: add package name and version to warning messages
• cargo: support public dependency configuration with workspace deps
• rustfmt: support let-chains
• rustdoc-search: add impl disambiguator to duplicate assoc items
• rustdoc: hide #[repr(transparent)] if it isn't part of the public ABI
• rustdoc: show crate name beside smaller logo
• clippy: get_first: lint on non-primitive slices
• clippy: manual_is_ascii_check: Also check for is_ascii_hexdigt
• clippy: unnecessary_lazy_eval: reduce applicability if closure has return type annotation
• clippy: fix ICE in internal author lint
• rust-analyzer: add replace_is_ok_with_if_let_ok assist
• rust-analyzer: add replace_is_some_with_if_let_some assist
• rust-analyzer: add diagnostics messages for chars and byte literal errors
• rust-analyzer: make cursor select at _tmp
• rust-analyzer: string literals diagnose

Rust Compiler Performance Triage

Overall an interesting week performance wise, with small improvements to a vast number of benchmarks seeming to outweigh an isolated set of (slightly) larger regressions. It included a number of PRs regressed instruction counts but did not matter for cycle times, plus one mysterious regression to check_match and mir_borrowck from reworking constructor splitting (see report on PR 116391 for details), and an awesome broad set of improvements from automatically inlining small functions across crates (see report on PR 116505 for details).

Triage done by @pnkfelix. Revision range: 84d44dd1..b9832e72

4 Regressions, 1 Improvements, 4 Mixed; 3 of them in rollups 84 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] 2024 Edition

Tracking Issues & PRs

• [disposition: merge] Tracking Issue for result_option_inspect
• [disposition: merge] Allow partially moved values in match
• [disposition: merge] read_dir has unexpected behavior for ""
• [disposition: merge] rustdoc: align stability badge to baseline instead of bottom

New and Updated RFCs

• [new] RFC: Superseding public/private dependencies
• [new] add float semantics RFC
• [new] Reserve gen keyword in 2024 edition and start an experiment implementation of Iterator generators

Call 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:

• No RFCs issued a call for testing 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.

Upcoming Events

Rusty Events between 2023-10-18 - 2023-11-15 🦀

Virtual

• 2023-10-18 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • Operating System Primitives (Atomics & Locks Chapter 8)
• 2023-10-18 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Pinning
• 2023-10-19 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-10-19 | Virtual (Stuttgart, DE) | Rust Community Stuttgart
  • Rust-Meetup
• 2023-10-24 | Virtual (Berlin, DE) | OpenTechSchool Berlin
  • Rust Hack and Learn | Mirror
• 2023-10-24 | Virtual (Washington, DC, US) | Rust DC
  • Month-end Rusting—Fun with 🍌 and 🔎!
• 2023-10-31 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2023-11-01 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • ECS with Bevy Game Engine
• 2023-11-01 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2023-11-02 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-11-09 | Virtual (Nuremberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2023-11-15 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • Building Our Own Locks (Atomics & Locks Chapter 9)
• 2023-11-15 | Virtual (Richmond, VA, US) | Linux Plumbers Conference
  • Rust Microconference in LPC 2023 (Nov 13-16)

Asia

• 2023-10-18 | Tokyo, JP | Tokyo Rust Meetup
  • Rust and the Age of High-Integrity Languages
• 2023-10-20 | Singapore, SG | Rust Meetup Singapore
  • Rust meetup @ Google Developer Space
• 2023-10-21 | Pune, IN | Rust Pune
  • Rust 101 and Decoding Fearless Concurrency

Europe

• 2023-10-19 | Amsterdam, NL | Rust Developers Amsterdam Group
  • Rust Amsterdam Meetup @ Terraform
• 2023-10-19 | Wrocław, PL | Rust Wrocław
  • Rust Meetup #35
• 2023-10-20 | Saarbrücken, DE | Rust-Saar
  • Rustlings Live Coding Session
• 2023-10-24 | Bucharest, RO | Rust Lang Bucharest Meetup
  • Rust Bucharest Meetup #4
• 2023-10-25 | Dublin, IE | Rust Dublin
  • Biome, web development tooling with Rust
• 2023-10-25 | Paris, FR | Rust Paris
  • Rust for the web - Paris meetup #61
• 2023-10-25 | Zagreb, HR | impl Zagreb for Rust
  • Rust Meetup 2023/10: Lunatic
• 2023-10-26 | Augsburg, DE | Rust - Modern Systems Programming in Leipzig
  • Augsburg Rust Meetup #3
• 2023-10-26 | Delft, NL | Rust Nederland
  • Rust at TU Delft
• 2023-10-26 | Lille, FR | Rust Lille
  • Rust Lille #4 at SFEIR
• 2022-10-30 | Stockholm, SE | Stockholm Rust
  • Rust Meetup @Aira + Netlight
• 2023-11-01 | Cologne, DE | Rust Cologne
  • Rust-Meetup November, Save the date
• 2023-11-07 | Brussels, BE | Rust Aarhus
  • Rust Aarhus - Rust and Talk beginners edition
• 2023-11-09 | Barcelona, ES | BcnRust
  • 11th BcnRust Meetup
• 2023-11-09 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup at Browns

North America

• 2023-10-18 | Brookline, MA, US | Boston Rust Meetup
  • Boston University Rust Lunch
• 2023-10-19 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2023-10-19 | Nashville, TN, US | Music City Rust Developers
  • Rust Goes Where It Pleases Pt2 - Rust on the front end!
• 2023-10-19 | Seattle, WA, US | Seattle Rust User Group
  • Seattle Rust User Group - October Meetup
• 2023-10-24 | Pasadena, CA, US | Pasadena Thursday Go/Rust
  • Monthly Rust group
• 2023-10-25 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2023-10-25 | Chicago, IL, US | Deep Dish Rust
  • Rust Happy Hour
• 2023-11-04 | Boulder, CO, US | Boulder Rust Meetup
  • Let's make a Discord bot!
• 2023-11-15 | Richmond, VA, US + Virtual | Linux Plumbers Conference
  • Rust Microconference in LPC 2023 (Nov 13-16)

Oceania

• 2023-10-17 | Christchurch, NZ | Christchurch Rust Meetup Group
  • Christchurch Rust meetup meeting
• 2023-10-9 | Sydney, NSW, AU | Rust Sydney
  • Demolition Day 🤯
• 2023-10-26 | Brisbane, QLD, AU | Rust Brisbane
  • October Meetup

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

When your Rust build times get slower after adding some procedural macros:

We call that the syn tax 🦀

– janet on fosstodon.org

Thanks to Jacob Pratt for the 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.

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust