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

• Leadership change in the Rust Infrastructure Team

Newsletters

• This Month in Rust OSDev: August 2023

Project/Tooling Updates

• rust-analyzer changelog #198
• Meet Yazi: Blazing fast terminal file manager, written in Rust, based on async I/O
• Candle: A New Machine Learning Framework for Rust
• Wasmer 4.2 is Released: Upping the Ante with 50% Faster Module Load Times! 🚀
• Roadmap to Tauri 2.0
• Introducing RustRover – A Standalone Rust IDE by JetBrains

Observations/Thoughts

• How Ferrocene improves Rust
• Owned values and Futures in Rust
• Semver violations are common, better tooling is the answer
• Rethinking Rust’s unsafe keyword
• Async Rust Is A Bad Language
• Why you might actually want async in your project
• I Wrote A String Type
• Writing a Web Scraper in Rust using Reqwest
• Gotchas in Rust-Python binding with pyo3

Rust Walkthroughs

• How Rust can build an elegant API around raw memory
• Deploy Your Rust Project to Any Hosting Provider in Minutes
• Rust embedded at Espressif @ Copenhagen Rust Community

Miscellaneous

• What's The Time In Tokio?
• Teaching Rust in 5 days
• Time Travel Debugging Rust in NeoVim
• Semantic Search with Qdrant, OpenAI and Shuttle
• ESP32 Standard Library Embedded Rust: GPIO Interrupts
• [audio] RustShip: Trustfall and cargo-semver-checks with Predrag Gruevski
• [video] How to Do Embedded Development with Rust • Steve Klabnik • GOTO 2023

Crate of the Week

This week's crate is irsenv, a hierarchical environmant variable manager.

Thanks to sysid 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.

• zerocopy - Prevent panics statically
• zerocopy - Implement traits for tuple types (and maybe other container types?)
• zerocopy - [CI] Deduplicate actions/cache directives
• zerocopy - Refactor version comparison logic in check_versions CI job
• r3bl_rs_utils - Add styling support so that selected and unselected styles can be passed in
• r3bl_rs_utils - Create a function that allows multiple selections from a list of strings
• r3bl_rs_utils - Add support for syntect output
• Ockam - Use the Terminal to print out RPC response instead of printlns - Issue #5904 - build-trust/ockam - GitHub
• Ockam - Investigate and fix breaking changes in upgrading from nix crate 0.26.2 to 0.27.1
• Ockam - Give user feedback on using Ockam Command CLI
• RustQuant - Increase test coverage.
• RustQuant - Create Python bindings.
• RustQuant - Add/improve documentation.
• RustQuant - Implement jump-diffusion simulator.

• hyper - hyper 1.0 API docs polish - meta issue

• Hyperswitch - log a placeholder if merchant_id is not found

• Hyperswitch - merchant account delete does not delete the merchant_key_store
• Hyperswitch - add domain type for client secret

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

Updates from the Rust Project

382 pull requests were merged in the last week

• move wasm32-wasi-preview1-threads target to Tier 2
• -Cllvm-args usability improvement
• debuginfo: add compiler option to allow compressed debuginfo sections
• rustc_layout, rustc_abi: make sure the types are well-formed
• abort if check nightly options failed on stable
• add CL and CMD into to pdb debug info
• add support to return value in StableMIR interface and not crash due to compilation error
• allow large_assignments for Box/Arc/Rc initialization
• allow redirecting subprocess stdout to our stderr etc. (redux)
• avoid a source_span query when encoding Spans into query results
• better Debug for Ty in smir
• bubble up opaque <eq> opaque operations instead of picking an order
• call LateLintPass::check_attribute from with_lint_attrs
• do not require associated types with Self: Sized to uphold bounds when confirming object candidate
• don't ICE on associated type projection without feature gate in new solver
• don't ICE when computing ctype's repr_nullable_ptr for possibly-unsized ty
• don't report any errors in lower_intrinsics
• don't require Drop for [PhantomData<T>; N] where N and T are generic, if T requires Drop
• don't suggest dereferencing to unsized type
• dont suggest use between use and cfg attr
• emit error instead of ICE when optimized MIR is missing
• enable incremental-relative-spans by default
• explain why we can mutate the FPU control word
• expose more information with DefId in smir
• extract parallel operations in rustc_data_structures::sync into a new parallel submodule
• fix ICE in improper_ctypes_definitions lint
• fix Step Skipping Caused by Using the --exclude Option
• fix homogeneous_aggregate not ignoring some ZST
• fix error report for size overflow from transmute
• fix overflow in array length computation
• fix: return early when has tainted in mir-lint
• implement fallback for effect param
• implement refinement lint for RPITIT
• implied bounds: do not ICE on unconstrained region vars
• improve "associated type not found" diagnostics
• improve AttrTokenStream
• improve diagnostic for generic params from outer items (E0401)
• fix unnecessary_unsafe false positive
• fix incorrect mutable suggestion information for binding in ref pattern like: let &b = a;
• lint node for private_bounds/private_interfaces is the item which names the private type
• lint on invalid usage of UnsafeCell::raw_get in reference casting
• make if let guard parsing consistent with normal guards
• make the deadlock panic clearly refer to a deadlock
• make unknown/renamed/removed lints passed via command line respect lint levels
• point out if a local trait has no implementations
• preserve ASAN-related symbols during LTO
• print the path of a return-position impl trait in trait when return_type_notation is enabled
• remove the unhelpful let binding diag comes from FormatArguments
• replace rustc_data_structures dependency with rustc_index in rustc_parse_format
• suggest iter_mut() where trying to modify elements from .iter()
• support debuginfo for custom MIR
• take &mut Results in ResultsVisitor
• use newtype_index for IntVid and FloatVid
• use relative positions inside a SourceFile
• use the same DISubprogram for each instance of the same inlined function within a caller
• represent MIR composite debuginfo as projections instead of aggregates
• encode only MIR reachable from other crates
• allow loading the SMIR for constants and statics
• implement SMIR generic parameter instantiation
• miri: catch function calls where the argument is caller-invalid / the return value callee-invalid
• miri: use #!/usr/bin/env shebang
• add optimized lock methods for Sharded and refactor Lock
• add FreezeLock type and use it to store Definitions
• use FreezeLock for CStore
• use Freeze for SourceFile
• span tweaks
• use a specialized varint + bitpacking scheme for DepGraph encoding
• add char::MIN
• stabilize io_error_other feature
• hashbrown: make allocator not Clone
• codegen_gcc: fix const handling in ATT syntax
• codegen_gcc: set the correct gimple output format
• cargo-credential: change serialization of cache expiration
• cargo: Add styling to help output
• cargo: Make resolver behavior independent of package order
• cargo: error out if cargo clean --doc is mixed with -p
• cargo: stabilize lints
• cargo: fix: don't print _TOKEN suggestion when not applicable
• cargo: fix: improve warning for both token & credential-provider
• rustdoc: add impl items from aliased type into sidebar
• rustdoc: add missing "Aliased type" title in the sidebar
• rustdoc: change syntax for anonymous functions set in JS
• rustdoc: list matching impls on type aliases
• rustdoc: render private fields in tuple struct as /* private fields */
• rustdoc: show inner enum and struct in type definition for concrete type
• rustfmt: Prefer light_rewrite_comment if it is not a doccomment
• rustfmt: fix checking if newline is needed before else in let-else statement
• clippy: implied_bounds_in_impls: include (previously omitted) associated types in suggestion
• clippy: slow_vector_initialization: use the source span of vec! macro and fix another FP
• clippy: add suggestions for std_instead_of_core
• clippy: auto deref does not apply on union field
• clippy: check binary operators and attributes in disallowed_macros
• clippy: ignore wildcards in function arguments and local bindings
• clippy: preserve literals and range kinds in manual_range_patterns
• clippy: rename incorrect_impls to non_canonical_impls, move them to warn by default
• rust-analyzer: add "Bind unused parameter" assist
• rust-analyzer: add into_to_qualified_from assist
• rust-analyzer: diagnose mismatched arg count for tuple struct patterns
• rust-analyzer: diagnose private fields in record constructor
• rust-analyzer: enable rust_analyzer for cfgs when code is being analyzed by rust-analyzer
• rust-analyzer: implement builtin#format_args, using rustc's format_args parser
• rust-analyzer: on type format '(', by adding closing ')' automatically
• rust-analyzer: parse builtin# syntax and add typechecking for builtin#offset_of expression
• rust-analyzer: clear native diagnostics on file closing
• rust-analyzer: disallow renaming of non-local items
• rust-analyzer: use crate name for CARGO_CRATE_NAME

Rust Compiler Performance Triage

An interesting week. We saw a massive improvement to instruction-counts across over a hundred benchmarks, thanks to #110050 an improved encoding scheme for the dependency graphs that underlie incremental-compilation. However, these instruction-count improvements did not translate to direct cycle time improvements. We also saw an improvement to our artifact sizes due to #115306. Beyond that, we had a scattering of small regressions to instruction-counts that were justified because they were associated with bug fixes.

Triage done by @pnkfelix. Revision range: 15e52b05..7e0261e7

3 Regressions, 2 Improvements, 5 Mixed; 2 of them in rollups 84 artifact comparisons made in total

Full report

Approved RFCs

Changes to Rust follow the Rust RFC (request for comments) process. These are the RFCs that were approved for implementation this week:

• Allow cfg-attributes in where clauses

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] Cargo Check T-lang Policy
• [disposition: merge] [RFC2603] Extend <const> to include str and structural constants.

Tracking Issues & PRs

• [disposition: merge] Raise minimum supported Apple OS versions
• [disposition: merge] Stabilize const_transmute_copy
• [disposition: merge] Don't resolve generic impls that may be shadowed by dyn built-in impls
• [disposition: merge] closure field capturing: don't depend on alignment of packed fields
• [disposition: merge] Accept additional user-defined syntax classes in fenced code blocks

New and Updated RFCs

• [new] Unify crate categories and keywords as tags
• [new] RFC: Cargo feature visibility (private/public)
• [new] RFC: Cargo feature deprecation
• [new] RFC: Cargo feature descriptions
• [new] Unsafe Extern Blocks

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 2023-09-13 - 2023-10-11 🦀

Virtual

• 2023-09-12 - 2023-09-15 | Virtual (Albuquerque, NM, US) | RustConf
  • RustConf 2023
• 2023-09-13 | Virtual (Boulder, CO, US) | Boulder Elixir and Rust
  • Monthly Meetup
• 2023-09-13 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • The unreasonable power of combinator APIs
• 2023-09-14 | Virtual (Nuremberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2023-09-19 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful—NeuronBench by Greg Hale
• 2023-09-20 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • SurrealDB for Rustaceans
• 2023-09-20 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2023-09-21 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-09-21 | Virtual (Cologne, DE) | Cologne AWS User Group #AWSUGCGN
  • AWS User Group Cologne - September Edition: Stefan Willenbrock: Developer Preview: Discovering Rust on AWS
• 2023-09-21 | Virtual (Linz, AT) | Rust Linz
  • Rust Meetup Linz - 33rd Edition
• 2023-09-21 | Virtual (Stuttgart, DE) | Rust Community Stuttgart
  • Rust-Meetup
• 2023-09-25 | Virtual (Dublin, IE) | Rust Dublin
  • How we built the SurrealDB Python client in Rust.
• 2023-09-26 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2023-10-03 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group, First Tuesdays
• 2023-10-04 | Virtual (Stuttgart, DE) | Rust Community Stuttgart
  • Rust-Meetup
• 2023-10-04 | Virtual (Various) | Ferrous Systems
  • A Decade of Rust with Ferrous Systems
• 2023-10-07 | Virtual (Kampala, UG) | Rust Circle Kampala
  • Rust Circle Meetup: Mentorship (First Saturday)
• 2023-10-10 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2023-10-11| Virtual (Boulder, CO, US) | Boulder Elixir and Rust
  • [Monthly Meetup]https://www.meetup.com/boulder-elixir-rust/events/zvxcsryfcnbpb/)

Asia

• 2023-10-03 | Taipei, TW | WebAssembly and Rust Meetup (Wasm Empowering AI)
  • WebAssembly Meetup (Wasm Empowering AI) in Taipei

Europe

• 2023-09-13 | Cologne, DE | Rust User Group Cologne
  • Rare Rust | Group Detail Page
• 2023-09-14 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup at Browns
• 2023-09-15 | Stuttgart, DE | Rust Community Stuttgart
  • Onsite Meeting
• 2023-09-15 | Tiel, NL | Rust, Getting Started
  • Rust Workshop - 2
• 2023-09-16 | Brussels, BE | HSBXL
  • Software Freedom Day 2023
• 2023-09-19 | Augsburg, DE | Rust - Modern Systems Programming in Leipzig
  • Logging and tracing in Rust
• 2023-09-21 | Aarhus, DK | Rust Aarhus
  • Rust Aarhus - Rust and Talk at Concordium
• 2023-09-21 | Bern, CH | Rust Bern
  • Rust Bern Meetup #3 2023 🦀
• 2023-09-26 | Berlin, DE | OpenTechSchool Berlin
  • Rust Hack and Learn
• 2023-09-28 | Berlin, DE | React Berlin
  • React Berlin September Meetup: Creating Videos with React & Remotion & More: Integrating Rust with React Native – Gheorghe Pinzaru
• 2023-09-28 | Madrid, ES | MadRust
  • Primer evento Post COVID: ¡Cervezas MadRust!
• 2023-09-30 | Saint Petersburg, RU | Rust Saint Petersburg meetups
  • Rust Community Meetup: A tale about how I tried to make my Blitz Basic - Vitaly; How to use nix to build projects on Rust – Danil; Getting to know tower middleware. General overview – Mikhail
• 2023-10-10 | Berlin, DE | OpenTechSchool Berlin
  • Rust Hack and Learn

North America

• 2023-09-12 - 2023-09-15 | Albuquerque, NM, US + Virtual | RustConf
  • RustConf 2023
• 2023-09-14 | Seattle, WA, US | Seattle Rust User Group Meetup
  • Seattle Rust User Group - August Meetup
• 2023-09-16 | Mountain View, CA, US | Rust Breakfast and Learn
  • Rust: breakfast & learn
• 2023-09-19 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2023-09-21 | Lehi, UT, US | Utah Rust
  • Real Time Multiplayer Game Server in Rust
• 2023-09-21 | Mountain View, CA, US| Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2023-09-21 | Nashville, TN, US | Music City Rust Developers
  • Rust on the web! Get started with Leptos
• 2023-09-23 | Mountain View, CA, US | Rust Breakfast and Learn
  • Rust: breakfast & learn
• 2023-09-26 | Pasadena, CA, US | Pasadena Thursday Go/Rust
  • Monthly Rust group
• 2023-09-27 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2023-09-30 | Mountain View, CA, US | Rust Breakfast and Learn
  • Rust: breakfast & learn
• 2023-10-07 | Mountain View, CA, US | Rust Breakfast and Learn
  • Rust: breakfast & learn

Oceania

• 2023-09-14 | Perth, WA, AU | Rust Perth
  • Rust Meetup 2: Lunch & Learn | Ticket Link
• 2023-09-19 | Christchurch, NZ | Christchurch Rust Meetup Group
  • Christchurch Rust meetup meeting
• 2023-09-26 | Canberra, ACT, AU | Rust Canberra
  • 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

It's very much a positive feedback loop: good tooling makes good tooling easier to build, so more of it gets built and the cycle repeats.
cargo-semver-checks stands on the shoulders of giants like rustc and rustdoc and Trustfall. Remove any one of them (or even just rustc's high-quality diagnostics!) and cargo-semver-checks wouldn't have been a viable project at all.

– Predrag Gruevski on /r/rust

Thanks to Vincent de Phily 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