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

Newsletters

• The Embedded Rustacean Issue #15
• This Week in Bevy: Foundations, Meetups, and more Bevy Cheatbook updates

Project/Tooling Updates

• rustc_codegen_gcc: Progress Report #31
• Slint 1.5: Embracing Android, Improving Live-Preview, and introducing Pythonic Slint
• yaml-rust2's first real release
• testresult 0.4.0 released. The crate provides the TestResult type for concise and precise test failures.
• Revolutionizing PostgreSQL Database Comparison: Introducing pgdatadiff in Rust — Unleash Speed, Safety, and Scalability

Observations/Thoughts

• SemVer in Rust: Breakage, Tooling, and Edge Cases — FOSDEM 2024 annotated talk
• Go's Errors: How I Learned to Love Rust
• Strongly-typed IDs in SurrealDB
• Iterators and traversables
• Using PostHog with Rust
• Using Rust on ESP32 from Windows
• Compiling Rust to WASI
• Achieving awful compression with digits of pi
• Zig, Rust, and other languages
• What part of Rust compilation is the bottleneck?
• Lambda on hard mode: Inside Modal's web infrastructure
• Embedded Rust Bluetooth on ESP: BLE Advertiser
• [video] Diplomat - Idiomatic Multi-Language APIs - Robert Bastian - Rust Zürisee March 2024

Rust Walkthroughs

• A Short Introduction to Rust and the Bevy Game Engine
• [video] Strings and memory reallocation in Rust

Research

• Rust Tools Survey (by JetBrains)

Miscellaneous

• RustNL 2024 schedule announced
• Fighting back: Turning the Tables on Web Scrapers Using Rust
• The book "Code Like a Pro in Rust" is released
• Red Hat's Long, Rust'ed Road Ahead For Nova As Nouveau Driver Successor

Crate of the Week

This week's crate is heck, a no_std crate to perform case conversions.

Thanks to Edoardo Morandi for the suggestion!

Please submit your suggestions and votes for next 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:

• 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.

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.

• Rama — add Form support (IntroResponse + FromRequest)
• Rama — rename *Filter matchers to *Matcher
• Rama — Provide support for boxed custom matchers in layer enums
• Rama — use workspace dependencies for common workspace dep versionning
• Rama — add open-telemetry middleware and extended prometheus support
• Space Acres - Packaging for MacOS
• Space Acres - Implement Loading Progress
• Space Acres - Show more lines of logs when the app is "Stopped with error"
• Space Acres - Tray Icon Support
• Hyperswitch - [REFACTOR]: Remove Default Case Handling - Braintree
• Hyperswitch - [REFACTOR]: Remove Default Case Handling - Fiserv
• Hyperswitch - [REFACTOR]: Remove Default Case Handling - Globepay
• ZeroCopy - Fix cfgs in rustdoc
• ZeroCopy - Audit uses of "C-like" and prefer "fieldless"
• ZeroCopy - in zerocopy-derive UI tests, detect whether we're building with RUSTFLAGS='-Wwarnings'

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.

• RustFest Zürich 2024 | Closes 2024-03-31 | Zürich, Switzerland | Event date: 2024-06-19 - 2024-06-24
• Oxidize 2024 | Closes 2024-03-24 | Berlin, Germany | Event date: 2024-05-28 - 2024-05-30
• RustConf 2024 | Closes 2024-04-25 | Montreal, Canada | Event date: 2024-09-10
• EuroRust 2024| Closes 2024-06-03 | Vienna, Austria & online | Event on 2024-10-10
• Scientific Computing in Rust 2024| Closes 2024-06-14 | online | Event date: 2024-07-17 - 2024-07-19

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

498 pull requests were merged in the last week

• BOLT Use CDSort and CDSplit
• NormalizesTo: return nested goals to caller
• add_retag: ensure box-to-raw-ptr casts are preserved for Miri
• f16 and f128 step 3: compiler support & feature gate
• add -Z external-clangrt
• add wasm_c_abi future-incompat lint
• add missing try_visit calls in visitors
• check library crates for all tier 1 targets in PR CI
• copy byval argument to alloca if alignment is insufficient
• coverage: initial support for branch coverage instrumentation
• create some minimal HIR for associated opaque types
• delay expand macro bang when there has indeterminate path
• delegation: fix ICE on duplicated associative items
• detect allocator for box in must_not_suspend lint
• detect calls to .clone() on T: !Clone types on borrowck errors
• detect when move of !Copy value occurs within loop and should likely not be cloned
• diagnostics: suggest Clone bounds when noop clone()
• do not eat nested expressions' results in MayContainYieldPoint format args visitor
• don't create ParamCandidate when obligation contains errors
• don't ICE when non-self part of trait goal is constrained in new solver
• don't show suggestion if slice pattern is not top-level
• downgrade const eval dangling ptr in final to future incompat lint
• enable PR tracking review assignment for rust-lang/rust
• enable creating backtraces via -Ztreat-err-as-bug when stashing errors
• enable frame pointers for the standard library
• ensure RPITITs are created before def-id freezing
• fix 32-bit overflows in LLVM composite constants
• fix ICE in diagnostics for parenthesized type arguments
• fix long-linker-command-lines failure caused by rust.rpath=false
• fix attribute validation on associated items in traits
• fix stack overflow with recursive associated types
• interpret: ensure that Place is never used for a different frame
• make incremental sessions identity no longer depend on the crate names provided by source code
• match lowering: don't collect test alternatives ahead of time
• more eagerly instantiate binders
• never patterns: suggest ! patterns on non-exhaustive matches
• only generate a ptrtoint in AtomicPtr codegen when absolutely necessary
• only invoke decorate if the diag can eventually be emitted
• pass the correct DefId when suggesting writing the aliased Self type out
• pattern analysis: Store field indices in DeconstructedPat to avoid virtual wildcards
• provide structured suggestion for #![feature(foo)]
• register LLVM handlers for bad-alloc / OOM
• reject overly generic assoc const binding types
• represent Result<usize, Box<T>> as ScalarPair(i64, ptr)
• split refining_impl_trait lint into _reachable, _internal variants
• stabilize imported_main
• stabilize associated type bounds (RFC #2289)
• stop walking the bodies of statics for reachability, and evaluate them instead
• ungate the UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES lint
• unix time module now return result
• validate builder::PATH_REMAP
• miri: add some chance to reuse addresses of previously freed allocations
• avoid lowering code under dead SwitchInt targets
• use UnsafeCell for fast constant thread locals
• add CStr::bytes iterator
• add as_(mut_)ptr and as_(mut_)slice to raw array pointers
• implement {Div,Rem}Assign<NonZero<X>> on X
• fix unsoundness in Step::forward_unchecked for signed integers
• implement Duration::as_millis_{f64,f32}
• optimize ptr::replace
• safe Transmute: Require that source referent is smaller than destination
• safe Transmute: Use 'not yet supported', not 'unspecified' in errors
• hashbrown: fix index calculation in panic guard of clone_from_impl
• cargo tree: Control --charset via auto-detecting config value
• cargo toml: Flatten manifest parsing
• cargo: add 'open-namespaces' feature
• cargo fix: strip feature dep when dep is dev dep
• cargo: prevent dashes in lib.name
• cargo: expose source/spans to Manifest for emitting lints
• rustdoc-search: depth limit T<U> → U unboxing
• rustdoc-search: search types by higher-order functions
• rustdoc: add --test-builder-wrapper arg to support wrappers such as RUSTC_WRAPPER when building doctests
• rustdoc: do not preload fonts when browsing locally
• rustfmt: fix: ICE with expanded code
• rustfmt: initial work on formatting headers
• clippy: cast_lossless: Suggest type alias instead of the aliased type
• clippy: else_if_without_else: Fix duplicate diagnostics
• clippy: map_entry: call the visitor on the local's else block
• clippy: option_option: Fix duplicate diagnostics
• clippy: unused_enumerate_index: trigger on method calls
• clippy: use_self: Make it aware of lifetimes
• clippy: don't emit doc_markdown lint for missing backticks if it's inside a quote
• clippy: fix dbg_macro false negative when dbg is inside some complex macros
• clippy: fix empty_docs trigger in proc-macro
• clippy: fix span calculation for non-ascii in needless_return
• clippy: handle false positive with map_clone lint
• clippy: lint when calling the blanket Into impl from a From impl
• clippy: move iter_nth to style, add machine applicable suggestion
• clippy: move readonly_write_lock to perf
• clippy: new restriction lint: integer_division_remainder_used
• rust-analyzer: distinguish integration tests from crates in test explorer
• rust-analyzer: apply #[cfg] to proc macro inputs
• rust-analyzer: implement ATPIT
• rust-analyzer: support macro calls in eager macros for IDE features
• rust-analyzer: syntax highlighting improvements
• rust-analyzer: fix panic with impl trait associated types in where clause
• rust-analyzer: don't auto-close block comments in strings
• rust-analyzer: fix wrong where clause rendering on hover
• rust-analyzer: handle attributes when typing curly bracket
• rust-analyzer: ignore some warnings if they originate from within macro expansions
• rust-analyzer: incorrect handling of use and panic issue in extract_module
• rust-analyzer: make inlay hint resolving work better for inlays targetting the same position
• rust-analyzer: refactor extension to support arbitrary shell command runnables
• rust-analyzer: show compilation progress in test explorer
• rust-analyzer: use --workspace and --no-fail-fast in test explorer

Rust Compiler Performance Triage

Even though the summary might not look like it, this was actually a relatively quiet week, with a few small regressions. The large regression that is also shown in the summary table was caused by extending the verification of incremental compilation results. However, this verification is not actually fully enabled by default, so these regressions are mostly only visible in our benchmarking suite, which enables the verification to achieve more deterministic benchmarking results. One small regression was also caused by enabling frame pointers for the Rust standard library, which should improve profiling of Rust programs.

Triage done by @kobzol. Revision range: e919669d..21d94a3d

Summary:

4 Regressions, 1 Improvements, 6 Mixed; 4 of them in rollups 67 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

• Reserve gen keyword in 2024 edition for Iterator generators

Tracking Issues & PRs

Rust

• [disposition: merge] Tracking Issue for raw slice len() method (slice_ptr_len, const_slice_ptr_len)
• [disposition: merge] downgrade ptr.is_aligned_to crate-private
• [disposition: merge] Stabilize unchecked_{add,sub,mul}
• [disposition: merge] transmute: caution against int2ptr transmutation
• [disposition: merge] Normalize trait ref before orphan check & consider ty params in alias types to be uncovered

Cargo

• [disposition: merge] release cargo test helper crate to crates-io

New and Updated RFCs

• [new] Add support for use Trait::method

Upcoming Events

Rusty Events between 2024-03-20 - 2024-04-17 🦀

Virtual

• 2024-03-20 | Virtual (Cardiff, UK) | Rust and C++ Cardiff
  • Rust for Rustaceans Book Club: Chapter 3 - Designing Interfaces
• 2024-03-20 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2024-03-21 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-03-26 | Virtual + In Person (Barcelona, ES) | BcnRust
  • 13th BcnRust Meetup - Stream
• 2024-03-26 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2024-03-28 | Virtual + In Person (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-04-02 | Virtual (Buffalo, NY, US) | Buffalo Rust
  • Buffalo Rust User Group
• 2024-04-03 | Virtual (Cardiff, UK) | Rust and C++ Cardiff
  • Rust for Rustaceans Book Club: Chapter 4 - Error Handling
• 2024-04-03 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2024-04-04 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-04-09 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2024-04-11 | Virtual + In Person (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-04-11 | Virtual (Nürnberg, DE) | Rust Nüremberg
  • Rust Nürnberg online
• 2024-04-16 | Virtual (Washinigton, DC, US) | Rust DC
  • Mid-month Rustful
• 2024-04-17| Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out

Africa

• 2024-04-05 | Kampala, UG | Rust Circle Kampala
  • Rust Circle Meetup

Asia

• 2024-03-30 | New Delhi, IN | Rust Delhi
  • Rust Delhi Meetup #6

Europe

• 2024-03-20 | Girona, ES | Rust Girona
  • Introduction to programming Microcontrollers with Rust
• 2024-03-20 | Lyon, FR | Rust Lyon
  • Rust Lyon Meetup #9
• 2024-03-20 | Oxford, UK | Oxford Rust Meetup Group
  • Introduction to Rust
• 2024-03-21 | Augsburg, DE | Rust Meetup Augsburg
  • Augsburg Rust Meetup #6
• 2024-03-21 | Lille, FR | Rust Lille
  • Rust Lille #6: Du RSS et de L'ECS !
• 2024-03-21 | Vienna, AT | Rust Vienna
  • Rust Vienna Meetup - March - Unsafe Rust
• 2024-03-23 | Stockholm, SE | Stockholm Rust
  • Ferris' Fika Forum | Map
• 2024-03-25 | London, UK | Rust London User Group
  • LDN Talks: Rust Nation 2024 Pre-Conference Meetup
• 2024-03-26 | Barcelona, ES + Virtual | BcnRust
  • 13th BcnRust Meetup
• 2024-03-26 - 2024-03-28 | London, UK | Rust Nation UK
  • Rust Nation 2024 - Conference
• 2024-03-28 | Berlin, DE | Rust Berlin
  • Rust and Tell
• 2024-04-10 | Cambridge, UK | Cambridge Rust Meetup
  • Rust Meetup Reboot 3
• 2024-04-10 | Oslo, NO | Rust Oslo
  • Rust Hack'n'Learn at Kampen Bistro
• 2024-04-11 | Bordeaux, FR | Rust Bordeaux
  • Rust Bordeaux #2 : Présentations
• 2024-04-11 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup at Browns
• 2024-04-16 | Bratislava, SK | Bratislava Rust Meetup Group
  • Rust Meetup by Sonalake #5
• 2024-04-16 | Munich, DE + Virtual | Rust Munich
  • Rust Munich 2024 / 1 - hybrid

North America

• 2024-03-21 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2024-03-21 | Nashville, TN, US | Music City Rust Developers
  • Rust Meetup : Lightning Round!
• 2024-03-21 | Seattle, WA, US | Seattle Rust User Group
  • Seattle Rust User Group Meetup
• 2024-03-21 | Spokane, WA, US | Spokane Rust Meetup | Spokane Rust Website
  • Presentation: Brilliance in Borrowing
• 2024-03-22 | Somerville, MA, US | Boston Rust Meetup
  • Somerville Union Square Rust Lunch, Mar 22
• 2024-03-26 | Minneapolis, MN, US | Minneapolis Rust Meetup
  • Minneapolis Rust: Getting started with Rust!
• 2024-03-27 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2024-03-27 | Hawthorne (Los Angeles), CA, US | Freeform
  • Rust in the Physical World 🦀 Tech Talk Event at Freeform
• 2024-03-31 | Boston, MA, US | Boston Rust Meetup
  • Beacon Hill Rust Lunch, Mar 31
• 2024-04-04 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2024-04-11 | Seattle, WA, US | Seattle Rust User Group
  • Seattle Rust User Group Meetup
• 2024-04-16 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person

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

In 10 years we went from “Rust will never replace C and C++” to “New C/C++ should not be written anymore, and you should use Rust”. Good job.

– dpc_pw on lobste.rs

Thanks to Dennis Luxen 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