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

• Announcing Rust 1.76.0
• This Development-cycle in Cargo: 1.77

Project/Tooling Updates

• zbus 4.0 released. zbus is a pure Rust D-Bus crate. The new version brings a more ergonomic and safer API. Release: zbus4
• This Month in Rust OSDev: January 2024
• Rerun 0.13 - real-time kHz time series in a multimodal visualizer
• egui 0.26 - Text selection in labels
• Hello, Selium! Yet another streaming platform, but easier

Observations/Thoughts

• Which red is your function?
• Porting libyaml to Safe Rust: Some Thoughts
• Design safe collection API with compile-time reference stability in Rust
• Cross compiling Rust to win32
• Modular: Mojo vs. Rust: is Mojo 🔥 faster than Rust 🦀 ?
• Extending Rust's Effect System
• Allocation-free decoding with traits and high-ranked trait bounds
• Cross-Compiling Your Project in Rust
• Kind: Our Rust library that provides zero-cost, type-safe identifiers
• Performance Roulette: The Luck of Code Alignment
• Too dangerous for C++
• Building an Uptime Monitor in Rust
• Box Plots at the Olympics
• Rust in Production: Interview with FOSSA
• Performance Pitfalls of Async Function Pointers (and Why It Might Not Matter)
• Error management in Rust, and libs that support it
• Finishing Turborepo's migration from Go to Rust
• Rust: Reading a file line by line while being mindful of RAM usage
• Why Rust? It's the safe choice
• [video] Rust 1.76.0: 73 highlights in 24 minutes!

Rust Walkthroughs

• Rust/C++ Interop Part 1 - Just the Basics
• Rust/C++ Interop Part 2 - CMake
• Speeding up data analysis with Rayon and Rust
• Calling Rust FFI libraries from Go
• Write a simple TCP chat server in Rust
• [video] Google Oauth with GraphQL API written in Rust - part 1. Registration mutation.

Miscellaneous

• The book "Asynchronous Programming in Rust" is released
• January 2024 Rust Jobs Report
• Chasing a bug in a SAT solver
• Rust for hardware vendors
• [audio] How To Secure Your Audio Code Using Rust With Chase Kanipe
• [audio] Tweede Golf - Rust in Production Podcast
• [video] RustConf 2023
• [video] Decrusting the tracing crate

Crate of the Week

This week's crate is microflow, a robust and efficient TinyML inference engine for embedded systems.

Thanks to matteocarnelos for the self-suggestion!

Please submit your suggestions and votes for next week!

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.

• Hyperswitch - [FEATURE]: Setup code coverage for local tests & CI
• Hyperswitch - [FEATURE]: Have get_required_value to use ValidationError in OptionExt

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

CFP - Speakers

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.

• Devoxx PL 2024 | CFP closes 2024-03-01 | Krakow, Poland | Event date: 2024-06-19 - 2024-06-21
• RustFest Zürich 2024 CFP closes 2024-03-31 | Zürich, Switzerland | Event date: 2024-06-19 - 2024-06-24

If you are an event organizer hoping to expand the reach of your event, please submit a link to the submission website through a PR to TWiR.

Updates from the Rust Project

466 pull requests were merged in the last week

• add armv8r-none-eabihf target for the Cortex-R52
• add lahfsahf and prfchw target feature
• check_consts: fix duplicate errors, make importance consistent
• interpret/write_discriminant: when encoding niched variant, ensure the stored value matches
• large_assignments: Allow moves into functions
• pattern_analysis: gather up place-relevant info
• pattern_analysis: track usefulness without interior mutability
• account for non-overlapping unmet trait bounds in suggestion
• account for unbounded type param receiver in suggestions
• add support for custom JSON targets when using build-std
• add unstable -Z direct-access-external-data cmdline flag for rustc
• allow restricted trait impls under #[allow_internal_unstable(min_specialization)]
• always check the result of pthread_mutex_lock
• avoid ICE in drop recursion check in case of invalid drop impls
• avoid a collection and iteration on empty passes
• avoid accessing the HIR in the happy path of coherent_trait
• bail out of drop elaboration when encountering error types
• build DebugInfo for async closures
• check that the ABI of the instance we are inlining is correct
• clean inlined type alias with correct param-env
• continue to borrowck even if there were previous errors
• coverage: split out counter increment sites from BCB node/edge counters
• create try_new function for ThinBox
• deduplicate tcx.instance_mir(instance) calls in try_instance_mir
• don't expect early-bound region to be local when reporting errors in RPITIT well-formedness
• don't skip coercions for types with errors
• emit a diagnostic for invalid target options
• emit more specific diagnostics when enums fail to cast with as
• encode coroutine_for_closure for foreign crates
• exhaustiveness: prefer "0..MAX not covered" to "_ not covered"
• fix ICE for deref coercions with type errors
• fix ErrorGuaranteed unsoundness with stash/steal
• fix cycle error when a static and a promoted are mutually recursive
• fix more ty::Error ICEs in MIR passes
• for E0223, suggest associated functions that are similar to the path
• for a rigid projection, recursively look at the self type's item bounds to fix the associated_type_bounds feature
• gracefully handle non-WF alias in assemble_alias_bound_candidates_recur
• harmonize AsyncFn implementations, make async closures conditionally impl Fn* traits
• hide impls if trait bound is proven from env
• hir: make sure all HirIds have corresponding HIR Nodes
• improve 'generic param from outer item' error for Self and inside static/const items
• improve normalization of Pointee::Metadata
• improve pretty printing for associated items in trait objects
• introduce enter_forall to supercede instantiate_binder_with_placeholders
• lowering unnamed fields and anonymous adt
• make min_exhaustive_patterns match exhaustive_patterns better
• make it so that async-fn-in-trait is compatible with a concrete future in implementation
• make privacy visitor use types more (instead of HIR)
• make traits / trait methods detected by the dead code lint
• mark "unused binding" suggestion as maybe incorrect
• match lowering: consistently lower bindings deepest-first
• merge impl_polarity and impl_trait_ref queries
• more internal emit diagnostics cleanups
• move path implementations into sys
• normalize type outlives obligations in NLL for new solver
• print image input file and checksum in CI only
• print kind of coroutine closure
• properly handle async block and async fn in if exprs without else
• provide more suggestions on invalid equality where bounds
• record coroutine kind in coroutine generics
• remove some unchecked_claim_error_was_emitted calls
• resolve: unload speculatively resolved crates before freezing cstore
• rework support for async closures; allow them to return futures that borrow from the closure's captures
• static mut: allow mutable reference to arbitrary types, not just slices and arrays
• stop bailing out from compilation just because there were incoherent traits
• suggest [tail @ ..] on [..tail] and [...tail] where tail is unresolved
• suggest less bug-prone construction of Duration in docs
• suggest name value cfg when only value is used for check-cfg
• suggest pattern tests when modifying exhaustiveness
• suggest turning if let into irrefutable let if appropriate
• suppress suggestions in derive macro
• take empty where bounds into account when suggesting predicates
• toggle assert_unsafe_precondition in codegen instead of expansion
• turn the "no saved object file in work product" ICE into a translatable fatal error
• warn on references casting to bigger memory layout
• unstably allow constants to refer to statics and read from immutable statics
• use the same mir-opt bless targets on all platforms
• enable MIR JumpThreading by default
• fix mir pass ICE in the presence of other errors
• miri: fix ICE with symbolic alignment check on extern static
• miri: implement the mmap64 foreign item
• prevent running some code if it is already in the map
• A trait's local impls are trivially coherent if there are no impls
• use ensure when the result of the query is not needed beyond its Resultness
• implement SystemTime for UEFI
• implement sys/thread for UEFI
• core/time: avoid divisions in Duration::new
• core: add Duration constructors
• make NonZero constructors generic
• reconstify Add
• replace pthread RwLock with custom implementation
• simd intrinsics: add simd_shuffle_generic and other missing intrinsics
• cargo: test-support: remove special case for $message_type
• cargo: don't add the new package to workspace.members if there is no existing workspace in Cargo.toml
• cargo: enable edition migration for 2024
• cargo: feat: add hint for adding members to workspace
• cargo: fix confusing error messages for sparse index replaced source
• cargo: fix: don't duplicate comments when editing TOML
• cargo: relax a test to permit warnings to be emitted, too
• rustdoc: Correctly generate path for non-local items in source code pages
• bindgen: add target mappings for riscv64imac and riscv32imafc
• bindgen: feat: add headers option
• clippy: mem_replace_with_default No longer triggers on unused expression
• clippy: similar_names: don't raise if the first character is different
• clippy: to_string_trait_impl: avoid linting if the impl is a specialization
• clippy: unconditional_recursion: compare by Tys instead of DefIds
• clippy: don't allow derive macros to silence disallowed_macros
• clippy: don't lint incompatible_msrv in test code
• clippy: extend NONMINIMAL_BOOL lint
• clippy: fix broken URL in Lint Configuration
• clippy: fix false positive in redundant_type_annotations lint
• clippy: add autofixes for unnecessary_fallible_conversions
• clippy: fix: ICE when array index exceeds usize
• clippy: refactor implied_bounds_in_impls lint
• clippy: return Some from walk_to_expr_usage more
• clippy: stop linting blocks_in_conditions on match with weird attr macro case
• rust-analyzer: abstract more over ItemTreeLoc-like structs
• rust-analyzer: better error message for when proc-macros have not yet been built
• rust-analyzer: add "unnecessary else" diagnostic and fix
• rust-analyzer: add break and return postfix keyword completions
• rust-analyzer: add diagnostic with fix to replace trailing return <val>; with <val>
• rust-analyzer: add incorrect case diagnostics for traits and their associated items
• rust-analyzer: allow cargo check to run on only the current package
• rust-analyzer: completion list suggests constructor like & builder methods first
• rust-analyzer: improve support for ignored proc macros
• rust-analyzer: introduce term search to rust-analyzer
• rust-analyzer: create UnindexedProject notification to be sent to the client
• rust-analyzer: substitute $saved_file in custom check commands
• rust-analyzer: fix incorrect inlining of functions that come from MBE macros
• rust-analyzer: waker_getters tracking issue from 87021 for 96992
• rust-analyzer: fix macro transcriber emitting incorrect lifetime tokens
• rust-analyzer: fix target layout fetching
• rust-analyzer: fix tuple structs not rendering visibility in their fields
• rust-analyzer: highlight rustdoc
• rust-analyzer: preserve where clause when builtin derive
• rust-analyzer: recover from missing argument in call expressions
• rust-analyzer: remove unnecessary .as_ref() in generate getter assist
• rust-analyzer: validate literals in proc-macro-srv FreeFunctions::literal_from_str
• rust-analyzer: implement literal_from_str for proc macro server
• rust-analyzer: implement convert to guarded return assist for let statement with type that implements std::ops::Try

Rust Compiler Performance Triage

Relatively balanced results this week, with more improvements than regressions. Some of the larger regressions are not relevant, however there was a real large regression on doc builds, that was caused by a correctness fix (rustdoc was doing the wrong thing before).

Triage done by @kobzol. Revision range: 0984becf..74c3f5a1

Summary:

6 Regressions, 5 Improvements, 8 Mixed; 5 of them in rollups 53 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:

• eRFC: Iterate on and stabilize libtest's programmatic output

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: Rust Has Provenance

Tracking Issues & PRs

Rust

• [disposition: close] Implement Future for Option<F>
• [disposition: merge] Tracking Issue for min_exhaustive_patterns
• [disposition: merge] Make unsafe_op_in_unsafe_fn warn-by-default starting in 2024 edition

Cargo

• [disposition: merge] feat: respect rust-version when generating lockfile

New and Updated RFCs

• No New or Updated RFCs were created this week.

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:

• RFC: Checking conditional compilation at compile time
• Testing steps

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 2024-02-14 - 2024-03-13 💕 🦀 💕

Virtual

• 2024-02-15 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn
• 2024-02-15 | Virtual + In person (Praha, CZ) | Rust Czech Republic
  • Introduction and Rust in production
• 2024-02-19 | Virtual (Melbourne, VIC, AU)| Rust Melbourne
  • (Hybrid - in person & online) February 2024 Rust Melbourne Meetup - Day 1
• 2024-02-20 | Virtual (Melbourne, VIC, AU) | Rust Melbourne
  • (Hybrid - in person & online) February 2024 Rust Melbourne Meetup - Day 2
• 2024-02-20 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2024-02-20 | Virtual | Rust for Lunch
  • Lunch
• 2024-02-21 | Virtual (Cardiff, UK) | Rust and C++ Cardiff
  • Rust for Rustaceans Book Club: Chapter 2 - Types
• 2024-02-21 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2024-02-22 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-02-27 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2024-02-29 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup | Mirror: Berline.rs page
• 2024-02-29 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Surfing the Rusty Wireless Waves with the ESP32-C3 Board
• 2024-03-06 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2024-03-07 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-03-12 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2024-03-12 | Hybrid (Virtual + In-person) Munich, DE | Rust Munich
  • Rust Munich 2024 / 1 - hybrid

Asia

• 2024-02-17 | New Delhi, IN | Rust Delhi
  • Meetup #5

Europe

• 2024-02-15 | Copenhagen, DK | Copenhagen Rust Community
  • Rust Hacknight #2: Compilers
• 2024-02-15 | Praha, CZ - Virtual + In-person | Rust Czech Republic
  • Introduction and Rust in production
• 2024-02-21 | Lyon, FR | Rust Lyon
  • Rust Lyon Meetup #8
• 2024-02-22 | Aarhus, DK | Rust Aarhus
  • Rust and Talk at Partisia
• 2024-02-29 | Berlin, DE | Rust Berlin
  • Rust and Tell - Season start 2024
• 2024-03-12 | Munich, DE + Virtual | Rust Munich
  • Rust Munich 2024 / 1 - hybrid

North America

• 2024-02-15 | Boston, MA, US | Boston Rust Meetup
  • Back Bay Rust Lunch, Feb 15
• 2024-02-15 | Seattle, WA, US | Seattle Rust User Group
  • Seattle Rust User Group Meetup
• 2024-02-20 | New York, NY, US | Rust NYC
  • Rust NYC Monthly Mixer (Moved to Feb 20th)
• 2024-02-20 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2024-02-21 | Boston, MA, US | Boston Rust Meetup
  • Evening Boston Rust Meetup at Microsoft, February 21
• 2024-02-22 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2024-02-28 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2024-03-07 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo

Oceania

• 2024-02-19 | Melbourne, VIC, AU + Virtual | Rust Melbourne
  • (Hybrid - in person & online) February 2024 Rust Melbourne Meetup - Day 1
• 2024-02-20 | Melbourne, VIC, AU + Virtual | Rust Melbourne
  • (Hybrid - in person & online) February 2024 Rust Melbourne Meetup - Day 2
• 2024-02-27 | Canberra, ACT, AU | Canberra Rust User Group
  • February Meetup
• 2024-02-27 | Sydney, NSW, AU | Rust Sydney
  • 🦀 spire ⚡ & Quick
• 2024-03-05 | Auckland, NZ | Rust AKL
  • Rust AKL: Introduction to Embedded Rust + The State of Rust UI

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

For some weird reason the Elixir Discord community has a distinct lack of programmer-socks-wearing queer furries, at least compared to Rust, or even most other tech-y Discord servers I’ve seen. It caused some weird cognitive dissonance. Why do I feel vaguely strange hanging out online with all these kind, knowledgeable, friendly and compassionate techbro’s? Then I see a name I recognized from elsewhere and my hindbrain goes “oh thank gods, I know for a fact she’s actually a snow leopard in her free time”. Okay, this nitpick is firmly tongue-in-cheek, but the Rust user-base continues to be a fascinating case study in how many weirdos you can get together in one place when you very explicitly say it’s ok to be a weirdo.

– SimonHeath on the alopex Wiki's ElixirNitpicks page

Thanks to Brian Kung 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.

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