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 X(formerly 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.

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Updates from Rust Community

Project/Tooling Updates

• ratatui - v0.27.0
• Introduction - ChoRus
• uuid now properly supports version 7 counters
• Godot-Rust - June 2024 update
• piggui v0.2.0
• git-cliff 2.4.0 is released!

Observations/Thoughts

• Claiming, auto and otherwise
• Ownership
• Puzzle: Sharing declarative args between top level and subcommand using Clap
• Will Rust be alive in 10 years?
• Why WebAssembly came to the Backend (Wasm in the wild part 3)
• in-place construction seems surprisingly simple?
• Igneous Linearizer
• Life in the FastLanes
• Rust's concurrency model vs Go's concurrency model: stackless vs stackfull coroutines

Rust Walkthroughs

• Master Rust by Playing Video Games!
• Tokio Waker Instrumentation
• Build with Naz : Comprehensive guide to nom parsing
• Running a TLC5940 with an ESP32 using the RMT peripheral
• Rust Data-Structures: What is a CIDR trie and how can it help you?
• Rust patterns: Micro SDKs
• [series] The Definitive Guide to Error Handling in Rust (part 1): Dynamic Errors

Research

• When Is Parallelism Fearless and Zero-Cost with Rust?

Miscellaneous

• An Interview with Luca Palmieri of Mainmatter

Crate of the Week

This week's crate is cargo-binstall, a cargo subcommand to install crates from binaries out of their github releases.

Thanks to Jiahao XU for the self-suggestion!

Please submit your suggestions and votes for next week!

Calls 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:

RFCs

• No calls for testing were issued this week.

Rust

• No calls for testing were issued this week.

Rustup

• 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.

• cargo-generate - RFC on reading toml values into placeholders

If you are a Rust project owner and are looking for contributors, please submit tasks here or through a PR to TWiR or by reaching out on X (Formerly twitter) or Mastodon!

CFP - Events

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.

• Rust Ukraine 2024 | Closes 2024-07-06 | Online + Ukraine, Kyiv | Event date: 2024-07-27
• Conf42 Rustlang 2024 | Closes 2024-07-22 | online | Event date: 2024-08-22

If you are an event organizer hoping to expand the reach of your event, please submit a link to the website through a PR to TWiR or by reaching out on X (Formerly twitter) or Mastodon!

Updates from the Rust Project

428 pull requests were merged in the last week

• hir_typeck: be more conservative in making "note caller chooses ty param" note
• rustc_type_ir: Omit some struct fields from Debug output
• account for things that optimize out in inlining costs
• actually taint InferCtxt when a fulfillment error is emitted
• add #[rustc_dump_{predicates,item_bounds}]
• add hard error and migration lint for unsafe attrs
• allow "C-unwind" fn to have C variadics
• allow constraining opaque types during subtyping in the trait system
• allow constraining opaque types during various unsizing casts
• allow tracing through item_bounds query invocations on opaques
• ban ArrayToPointer and MutToConstPointer from runtime MIR
• change a DefineOpaqueTypes::No to Yes in diagnostics code
• collect attrs in const block expr
• coverage: add debugging flag -Zcoverage-options=no-mir-spans
• coverage: overhaul validation of the #[coverage(..)] attribute
• do not allow safe/unsafe on static and fn items
• don't ICE when encountering an extern type field during validation
• fix: break inside async closure has incorrect span for enclosing closure
• E0308: mismatched types, when expr is in an arm's body, don't add semicolon ';' at the end of it
• improve conflict marker recovery
• improve tip for inaccessible traits
• interpret: better error when we ran out of memory
• make async drop code more consistent with regular drop code
• make edition dependent :expr macro fragment act like the edition-dependent :pat fragment does
• make pretty printing for f16 and f128 consistent
• match lowering: expand or-candidates mixed with candidates above
• show notice about "never used" of Debug for enum
• stop sorting Spans' SyntaxContext, as that is incompatible with incremental
• suggest inline const blocks for array initialization
• suggest removing unused tuple fields if they are the last fields
• uplift next trait solver to rustc_next_trait_solver
• add f16 and f128
• miri: /miri: nicer error when building miri-script fails
• miri: unix/foreign_items: move getpid to the right part of the file
• miri: don't rely on libc existing on Windows
• miri: fix ICE caused by seeking past i64::MAX
• miri: implement LLVM x86 adx intrinsics
• miri: implement LLVM x86 bmi intrinsics
• miri: nicer batch file error when building miri-script fails
• miri: use strict ops instead of checked ops
• save 2 pointers in TerminatorKind (96 → 80 bytes)
• add SliceLike to rustc_type_ir, use it in the generic solver code (+ some other changes)
• std::unix::fs: copy simplification for apple
• std::unix::os::home_dir: fallback's optimisation
• replace f16 and f128 pattern matching stubs with real implementations
• add PidFd::{kill, wait, try_wait}
• also get add nuw from uN::checked_add
• generalize {Rc, Arc}::make_mut() to unsized types
• implement array::repeat
• make Option::as_[mut_]slice const
• rename std::fs::try_exists to std::fs::exists and stabilize fs_try_exists
• replace sort implementations
• return opaque type from PanicInfo::message()
• stabilise c_unwind
• std: refactor the thread-local storage implementation
• hashbrown: implement XxxAssign operations on HashSets
• hashbrown: replace "ahash" with "default-hasher" in Cargo features
• cargo toml: warn when edition is unset, even when MSRV is unset
• cargo: add CodeFix::apply_solution and impl Clone
• cargo: make -Cmetadata consistent across platforms
• cargo: simplify checking feature syntax
• cargo: simplify checking for dependency cycles
• cargo test: add auto-redaction for not found error
• cargo test: auto-redact file number
• rustdoc: add support for missing_unsafe_on_extern feature
• implement use<> formatting in rustfmt
• rustfmt: format safety keywords on static items
• remove stray println from rustfmt's rewrite_static
• resolve clippy f16 and f128 unimplemented!/FIXMEs
• clippy: missing_const_for_fn: add machine-applicable suggestion
• clippy: add applicability filter to lint list page
• clippy: add more types to is_from_proc_macro
• clippy: don't lint implicit_return on proc macros
• clippy: fix incorrect suggestion for manual_unwrap_or_default
• clippy: resolve clippy::invalid_paths on bool::then
• clippy: unnecessary call to min/max method
• rust-analyzer: complete async keyword
• rust-analyzer: check that Expr is none before adding fixup
• rust-analyzer: add toggleLSPLogs command
• rust-analyzer: add space after specific keywords in completion
• rust-analyzer: filter builtin macro expansion
• rust-analyzer: don't remove parentheses for calls of function-like pointers that are members of a struct or union
• rust-analyzer: ensure there are no cycles in the source_root_parent_map
• rust-analyzer: fix IDE features breaking in some attr macros
• rust-analyzer: fix flycheck panicking when cancelled
• rust-analyzer: handle character boundaries for wide chars in extend_selection
• rust-analyzer: improve hover text in unlinked file diagnostics
• rust-analyzer: only show unlinked-file diagnostic on first line during startup
• rust-analyzer: pattern completions in let-stmt
• rust-analyzer: use ItemInNs::Macros to convert ModuleItem to ItemInNs
• rust-analyzer: remove panicbit.cargo extension warning
• rust-analyzer: simplify some term search tactics
• rust-analyzer: term search: new tactic for associated item constants

Rust Compiler Performance Triage

Mostly a number of improvements driven by MIR inliner improvements, with a small number benchmarks having a significant regression due to improvements in sort algorithms, which are runtime improvements at the cost of usually slight or neutral compile time regressions, with outliers in a few cases.

Triage done by @simulacrum. Revision range: c2932aaf..c3d7fb39

See full report for details.

Approved RFCs

Changes to Rust follow the Rust RFC (request for comments) process. These are the RFCs that were approved for implementation this week: * Change crates.io policy to not offer crate transfer mediation * UnsafePinned: allow aliasing of pinned mutable references

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] RFC: Return Type Notation
• [disposition: merge] Add a general mechanism of setting RUSTFLAGS in Cargo for the root crate only
• [disposition: close] Allow specifying dependencies for individual artifacts

Tracking Issues & PRs

Rust

• [disposition: merge] #![crate_name = EXPR] semantically allows EXPR to be a macro call but otherwise mostly ignores it
• [disposition: merge] Add nightly style guide section for precise_capturing use<> syntax
• [disposition: merge] Tracking issue for PanicInfo::message
• [disposition: merge] Tracking issue for Cell::update
• [disposition: \<unspecified>] Tracking issue for core::arch::{x86, x86_64}::has_cpuid
• [disposition: merge] Syntax for precise capturing: impl Trait + use<..>
• [disposition: merge] Remove the box_pointers lint.
• [disposition: merge] Re-implement a type-size based limit
• [disposition: merge] Tracking Issue for duration_abs_diff
• [disposition: merge] Check alias args for WF even if they have escaping bound vars

Cargo

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

Language Team

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

Language Reference

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

Unsafe Code Guidelines

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

New and Updated RFCs

• [new] Cargo structured syntax for feature dependencies on crates
• [new] Mergeable rustdoc cross-crate info
• [new] Add "crates.io: Crate Deletions" RFC

Upcoming Events

Rusty Events between 2024-06-26 - 2024-07-24 🦀

Virtual

• 2024-06-27 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-07-02 | Virtual (Buffalo, NY) | Buffalo Rust Meetup
  • Buffalo Rust User Group
• 2024-07-02 | Hybrid - Virtual and In-person (Los Angeles, CA, US) | Rust Los Angeles
  • Rust LA Reboot
• 2024-07-03 | Virtual | Training 4 Programmers LLC
  • Build Web Apps with Rust and Leptos
• 2024-07-03 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2024-07-04 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-07-06 | Virtual (Kampala, UG) | Rust Circle Kampala
  • Rust Circle Meetup
• 2024-07-09 | Virtual | Rust for Lunch
  • July 2024 Rust for Lunch
• 2024-07-09 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2024-07-10 | Virtual | Centre for eResearch
  • Research Computing With The Rust Programming Language
• 2024-07-11 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2024-07-11 | Hybrid - Virtual and In-person (Mexico City, DF, MX) | Rust MX
  • Programación de sistemas con Rust
• 2024-07-11 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2024-07-11 | Virtual (Tel Aviv, IL) | Code Mavens
  • Reading JSON files in Rust (English)
• 2024-07-16 | Virtual (Tel Aviv, IL) | Code Mavens
  • Web development in Rust using Rocket - part 2 (English)
• 2024-07-17 | Hybrid - Virtual and In-person (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2024-07-18 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-07-23| Hybrid - Virtual and In-Person (München/Munich, DE) | Rust Munich
  • Rust Munich 2024 / 2 - hybrid
• 2024-07-24 | Virtual | Women in Rust
  • Lunch & Learn: Exploring Rust API Use Cases

Asia

• 2024-06-30 | Kyoto, JP | Kyoto Rust
  • Rust Talk: Cross Platform Apps
• 2024-07-03 | Tokyo, JP | Tokyo Rust Meetup
  • I Was Understanding WASM All Wrong!

Europe

• 2024-06-27 | Berlin, DE | Rust Berlin
  • Rust and Tell - Title
• 2024-06-27 | Copenhagen, DK | Copenhagen Rust Community
  • Rust meetup #48 sponsored by Google!
• 2024-07-10 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup - July
• 2024-07-11 | Prague, CZ | Rust Prague
  • Rust Meetup Prague (July 2024)
• 2024-07-16 | Leipzig, DE | Rust - Modern Systems Programming in Leipzig
  • Building a REST API in Rust using Axum, SQLx and SQLite
• 2024-07-16 | Mannheim, DE | Hackschool - Rhein-Neckar
  • Nix Your Bugs & Rust Your Engines #4
• 2024-07-23| Hybrid - Virtual and In-Person (München/Munich, DE) | Rust Munich
  • Rust Munich 2024 / 2 - hybrid

North America

• 2024-06-26 | Austin, TX, US | Rust ATC
  • Rust Lunch - Fareground
• 2024-06-27 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2024-06-27 | Nashville, TN, US | Music City Rust Developers
  • Music City Rust Developers: Holding Pattern
• 2024-06-27 | St. Louis, MO, US | STl Rust
  • Meet and Greet Hacker session
• 2024-07-02 | Hybrid - Los Angeles, CA, US | Rust Los Angeles
  • Rust LA Reboot
• 2024-07-05 | Boston, MA, US | Boston Rust Meetup
  • Boston University Rust Lunch, July 5
• 2024-07-11 | Hybrid - Mexico City, DF, MX | Rust MX
  • Programación de sistemas con Rust
• 2024-07-11 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2024-07-17 | Hybrid - Vancouver, BC, CA | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2024-07-18 | Nashville, TN, US | Music City Rust Developers
  • Music City Rust Developers : holding pattern
• 2024-07-24 | Austin, TX, US | Rust ATC
  • Rust Lunch - Fareground

Oceania

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

Rust has no theoretical inconsistencies... a remarkable achievement...

– Simon Peyton-Jones on YouTube

Thanks to ZiCog for the suggestion and Simon Farnsworth for the improved link!

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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Discuss on r/rust