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? Tweet us at @ThisWeekInRust or send us a pull request. Want to get involved? We love contributions.

This Week in Rust is openly developed on GitHub. If you find any errors in this week's issue, please submit a PR.

Updates from Rust Community

Official

• Const Eval (Un)Safety Rules

Project/Tooling Updates

• Wasmtime Reaches 1.0: Fast, Safe and Production Ready!
• clap 4.0, a Rust CLI argument parser
• rust-analyzer changelog #147
• Announcing tauri-egui 0.1.0

Observations/Thoughts

• Aembit: Why We Chose Rust
• Ten challenges for Rust
• Futures Concurrency IV: Join Ergonomics
• Dyn async traits, part 8: the soul of Rust
• What I meant by the "soul of Rust"
• PostgresML is Moving to Rust for our 2.0 Release
• Bringing Up TLS on Precursor
• [video] curl-up 2022: hyper in curl
• [audio] Rust at Microsoft with Nell Shamrell-Harrington
• [audio] Axum with David Pedersen

Rust Walkthroughs

• Implementing the Display Trait on a Generic Array using Newtype Pattern
• A Strong Typing Example
• Rust Bevy Entity Component System
• [video] 1Password Developer Fireside Chat: Serde Deserializers
• [video] Introduction to Async

Miscellaneous

• Linus Torvalds: Rust will go into Linux 6.1

Crate of the Week

This week's crate is match_deref, a macro crate to implement deref patterns on stable Rust.

Thanks to meithecatte for the suggestion!

Please submit your suggestions and votes for next week!

Call for Participation

Always wanted to contribute to open-source projects but didn't 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.

• Ockam - Implement ockam status command
• Ockam - Make ockam identity show command work without creating nodes
• Ockam - Break down ockam command bats tests

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

Updates from the Rust Project

347 pull requests were merged in the last week

• stabilize let else (RFC #3137)
• stabilize generic associated types (RFC #1598)
• initial implementation of dyn*
• fix #[link kind="raw-dylib"] to respect #[link_name]
• disallow defaults on type GATs
• compute lint levels by definition
• deny return-position impl Trait in traits for object safety
• do not suggest a placeholder to const and static without a type
• avoid infinite loop in function arguments checking
• fix ICE in opt_suggest_box_span
• be careful about expr_ty_adjusted when noting block tail type
• check that the types in return position impl Trait in traits are well-formed
• impove diagnostic for .awaiting non-futures
• suggest pub instead of public for const type item
• suggest associated const for incorrect use of let in traits
• miri: implement a garbage collector for tags
• miri: make sleep work with isolation enabled
• miri: run the GC more often on Linux, not MacOS
• do not fetch HIR node when iterating to find lint
• extend list of targets that support dyanmic linking for llvm tools
• normalize struct field types in confirm_builtin_unsize_candidate
• streamline register_res
• rustc_error, rustc_private: switch to stable hash containers
• change AccessLevels representation
• change FnMutDelegate to trait objects
• change rlib format to distinguish native dependencies
• ssa: implement #[collapse_debuginfo]
• translations: migrate rustc_session to use SessionDiagnostic - Final
• constify PartialEq for Ordering
• constify impl Fn &(mut) Fn
• constify some CStr methods
• use DisplayBuffer for socket addresses
• simplify const memchr
• implement std::marker::Tuple
• implement simd_as for pointers
• stdarch: riscv: P extension intrinsics for packed SIMD (part 1)
• cargo: expose cargo add internals as edit API
• cargo: take priority into account within the pending queue
• rustdoc: use more precise URLs for jump-to-definition links
• clippy: Add iter_kv_map lint
• clippy: Do not lint use_self in proc macro expansion
• clippy: Don't lint large_stack_array inside static items
• clippy: Don't panic on invalid shift while constfolding
• clippy: Fix FormatArgsExpn parsing of FormatSpec positions
• clippy: Fix almost_complete_letter_range false positive
• clippy: Fix unused_peekable closure and f(&mut peekable) false positives
• clippy: Make derivable_impls machine applicable
• clippy: Make module-style lints resilient to --remap-path-prefix
• clippy: Migrate write.rs to a late pass
• clippy: Use visit_expr_field for ParamPosition
• clippy: arithmetic-side-effects More non-overflowing ops
• clippy: arithmetic-side-effects Finish non-overflowing ops
• clippy: bool_to_int_with_if inverse case patch
• rust-analyzer: Add a new configuration settings to set env vars when running cargo, rustc, etc. commands: cargo.extraEnv and checkOnSave.extraEnv
• rust-analyzer: Add config to unconditionally prefer core imports over std
• rust-analyzer: Allow configuration of annotation location
• rust-analyzer: Complete variants and assoc items in path pattern through type aliases
• rust-analyzer: Ensure at least one trait bound in TyKind::DynTy
• rust-analyzer: Filter imports on find-all-references
• rust-analyzer: Fix add reference action on macros
• rust-analyzer: Fix prelude injection
• rust-analyzer: Move reference imports filtering into to_proto layer
• rust-analyzer: New assist: move_format_string_arg
• rust-analyzer: Fix a crash
• rust-analyzer: handle lifetime variables in projection normalization
• rust-analyzer: handle trait methods as inherent methods for trait-related types

Rust Compiler Performance Triage

This was a fairly negative week for compiler performance, with regressions overall up to 14% on some workloads (primarily incr-unchanged scenarios), largely caused by #101620. We are still chasing down either a revert or a fix for that regression, though a partial mitigation in #101862 has been applied. Hopefully the full fix or revert will be part of the next triage report.

We also saw a number of other regressions land, though most were much smaller in magnitude.

Triage done by @simulacrum. Revision range: 17cbdfd0..8fd6d03

See the full report for more details.

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.

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

• No RFCs entered Final Comment Period this week.

Tracking Issues & PRs

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

New and Updated RFCs

• RFC: Adding ArrayVec to core

Upcoming Events

Rusty Events between 2022-09-21 - 2022-10-19 🦀

Virtual

• 2022-09-21 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2022-09-22 | Virtual (Charlottesville, VA, US) | Charlottesville Rust Meetup
  • Rust based Bluetooth tools (BlueR) you can use today
• 2022-09-22 | Virtual (Tehran, IR) | Iran Rust Meetup
  • Rust Iran Meetup #9 - Let's Write An Async Executor
• 2022-09-23 | Virtual (Tokyo, JP) | Rust Tokyo
  • Rust Tokyo 2022
• 2022-09-27 | Virtual (Berlin, DE) | Berlin.rs
  • Rust Hack and Learn
• 2022-09-27 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2022-09-28 | Virtual (London, UK) | Rust London User Group
  • Rust (Hybrid) Hack & Learn September 2022
• 2022-09-30 | Virtual (Minneapolis, MN, US) | Minneapolis Rust Meetup
  • Beginner Rust Open "Office Hours"
• 2022-10-04 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group, First Tuesdays
• 2022-10-05 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2022-10-05 | Virtual (Stuttgart, DE) | Rust Community Stuttgart
  • Rust-Meetup
• 2022-10-06 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online #18
• 2022-10-08 | Virtual | Rust GameDev
  • Rust GameDev Monthly Meetup
• 2022-10-12 | Virtual (Boulder, CO, US) | Boulder Elixir and Rust
  • Monthly Meetup
• 2022-10-12 | Virtual (San Francisco, CA, US) | Microsoft Reactor San Francisco
  • Getting Started with Rust: Building Rust Projects
• 2022-10-15 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online #18
• 2022-10-18 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2022-10-19 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out

Asia

• 2022-09-24 | Beijing, CN | WebAssembly and Rust Meetup (Rustlang)
  • Rust 编程语言 meetup
• 2022-10-11 | Tokyo, JP | Tokyo Rust Meetup
  • Cost-Efficient Rust in Practice

Europe

• 2022-09-27 | Nijmegen, NL | Rust Nederland
  • Regular track: Rust at RU
  • Student track: Rust at RU
• 2022-09-28 | London, UK + Virtual | Rust London User Group
  • Rust (Hybrid) Hack & Learn September 2022
• 2022-09-29 | Amsterdam, NL | Rust Developers Amsterdam Group
  • Fiberplane Rust Workshop
• 2022-09-29 | Copenhagen, DK | Copenhagen Rust group
  • Rust Hack Night #29
• 2022-09-29 | Enschede, NL | Dutch Rust Meetup
  • Going full stack on Rust
• 2022-09-30 | Berlin, DE | RustFi Hackathon
  • RustFi Hackathon 30 Sept - 2 Oct
• 2022-10-02 | Florence, IT + Virtual | RustLab
  • RustLab Conference 2022 (Oct 2-4)
• 2022-10-03 | Stockholm, SE | Stockholm Rust
  • Rust Meetup @Microsoft Reactor
• 2022-10-12 | Berlin, DE | Rust Berlin
  • Rust and Tell - EuroRust B-Sides

North America

• 2022-09-22 | Lehi, UT, US | Utah Rust
  • Game Prototyping with Rusty Engine with Nathan Stocks and Food!
• 2022-09-28 | Austin, TX, US | Rust ATX
  • Rust Lunch
• 2022-09-29 | Ciudad de México, MX | Rust MX
  • Nuestra RustMX comunidad tiene página
• 2022-10-13 | Columbus, OH, US | Columbus Rust Society
  • Monthly Meeting
• 2022-10-18 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person

Oceania

• 2022-09-14 | Sydney, NSW, AU | Rust Sydney
  • Rust-Sydney Lightning Talks
• 2022-09-20 | Phillip, ACT, AU | Canberra Rust User Group
  • September 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

At the #LinuxPlumbers Rust MC: "I'm Matthew Wilcox, I'm one of the authors of the NVMe spec, I'm the one who suggested you make an NVMe driver to demonstrate the value of Rust. You have succeeded beyond my wildest expectations. These performance numbers are phenomenal."

– Josh Triplett paraphrasing Matthew Wilcox as spoken at the Linux Plumbers Conference Q&A session

Thanks to Josh Triplett for the self-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.

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Discuss on r/rust