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

Official

• November project goals update
• This Development-cycle in Cargo: 1.84
• December 2024 Project Director Update

Newsletters

• This Month in Rust OSDev: November 2024

Project/Tooling Updates

• hyper Roadmap 2025
• Bevy Fallible Systems, Bindless, and Immutable Components
• Sequoia PGP: A Sapling Matures: Meet sq 1.0
• Release 0.30.0 - egui_kittest and modals
• fish-shell 4.0b1, now in Rust
• Introducing Limbo: A complete rewrite of SQLite in Rust
• Streaming data analytics, Fluvio 0.14.0 release
• Announcing Hex Display: A modern xxd alternative
• Diesel: Window functions
• Rerun 0.21.0 - Graph view, 3D Grid & UI/UX improvements
• Introducing Fjädra — a Rust port of d3-force for graph layouts

Observations/Thoughts

• What are temporal and spatial memory safety?
• Reducing WASM binary size
• Crash recovery in 256 bytes
• Rust crate feature debugging
• [audio] Building Rust: An interview with Nell Shamrell-Harrington

Rust Walkthroughs

• Read the Code: Using Drop Safely in Rust
• Thoughts on Rust hashing
• Scheme to the Spec Part I: Concurrent Cycle Collection
• Solving Advent of Code at Compile Time with Rust Macros
• [video] Rust code reading: The thousands crate
• [video] Building a Lua package manager in Rust (Arabic)

Miscellaneous

• What is shift-left ⬅️ programming?
• Rust social status update 2024.12
• So many tokens, so little time: Introducing a faster, more flexible byte-pair tokenizer

Crate of the Week

This week's crate is cmd_lib, a library of command-line macros and utilities to write shell-script like tasks easily in Rust.

Thanks to Remo Senekowitsch for the 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

Rust

Rustup

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.

No Calls for participation were submitted this week.

If you are a Rust project owner and are looking for contributors, please submit tasks here or through a PR to TWiR!

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.

No Calls for papers or presentations were submitted this week.

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!

Updates from the Rust Project

437 pull requests were merged in the last week

• (Re-)Implement impl_trait_in_bindings
• rustc_borrowck: Stop suggesting the invalid syntax &mut raw const
• rustc_mir_dataflow cleanups, including some renamings
• rustc_target: ppc64 target string fixes for LLVM 20
• add AST support for unsafe binders
• add unpolished, experimental support for AFIDT (async fn in dyn trait)
• allow symbol_intern_string_literal lint in test modules
• arbitrary self types v2: main compiler changes
• change GetManyMutError to match T-libs-api decision
• check for array lengths that aren't actually usize
• codegen #[naked] functions using global asm
• correctly handle comments in attributes in doctests source code
• don't ICE when encountering never in range pattern
• don't make a def id for impl_trait_in_bindings
• don't show the full linker args unless --verbose is passed
• don't use AsyncFnOnce::CallOnceFuture bounds for signature deduction
• encode coroutine-closures in SMIR
• exercise const trait interaction with default fields
• fix ICE on type error in promoted
• fix ICE when multiple supertrait substitutions need assoc but only one is provided
• fix trimmed_def_paths ICE in the function ptr comparison lint
• fix our llvm::Bool typedef to be signed, to match LLVMBool
• interpret: reduce usage of TypingEnv::fully_monomorphized
• jsondocck: parse, don't validate commands
• keep track of parse errors in mods and don't emit resolve errors for paths involving them
• lint on combining #[no_mangle] and #[export_name]
• make Copy unsafe to implement for ADTs with unsafe fields
• make sure to use normalized ty for unevaluated const in default struct value
• modifies the index instruction from gep [0 x %Type] to gep %Type
• properly consider APITs for never type fallback ascription fix
• remove Lexer's dependency on Parser
• remove queries from the driver interface
• rudimentary heuristic to insert parentheses when needed for RPIT overcaptures lint
• some asm! diagnostic adjustments and a papercut fix
• some trait method vs impl method signature difference diagnostic cleanups
• suggest using deref in patterns
• suppress field expr with generics error message if it's a method
• try to evaluate constants in legacy mangling
• tweak multispan rendering to reduce output length
• use SourceMap to load debugger visualizer files
• use a more precise span in placeholder_type_error_diag
• use newly added exceptions to non default branch warning
• validate --skip and --exclude paths
• validate self in host predicates correctly
• bounds-check with PtrMetadata instead of Len in MIR
• miri: TB Optimization: Skip subtrees based on the subtree's root node's permissions
• miri: localtime_r: deduplicate timezone name allocation
• miri: use clap in miri-script
• stabilize const_nonnull_new
• stabilize async closures (RFC #3668)
• stabilize the Rust 2024 prelude
• UniqueRc trait impls
• std::net: Solaris supports SOCK_CLOEXEC as well since 11.4
• add value accessor methods to Mutex and RwLock
• de-duplicate and improve definition of core::ffi::c_char
• run TLS destructors for wasm32-wasip1-threads
• wasi/fs: improve stopping condition for <ReadDir as Iterator>::next
• codegen_gcc: stabilize lang_tests_common config parsing logic
• codegen_gcc: use casts instead of bitcast between pointers and integers to fix issues when using the lld linker
• cargo: build-script: Pass CARGO_CFG_FEATURE
• cargo: SourceId: use stable hash from rustc-stable-hash
• cargo: base: Support bases in patches in virtual manifests
• cargo: build-rs: Implicitly report rerun-if-env-changed for input
• cargo: resolver: Don't report all versions as rejected
• cargo: resolver: In errors, show rejected versions over alt versions
• cargo: resolver: Report invalid index entries
• cargo: resolver: Report unmatched versions, rather than saying no package
• cargo: script: Don't override the release profile
• cargo: a faster hash for ActivationsKey
• cargo: implement --depth workspace for cargo tree command
• cargo: emit_serialized_unit_graph uses the configured shell
• rustdoc-search: fix mismatched path when parent re-exported twice
• rustdoc-search: handle impl Into<X> better
• rustdoc: fix self cmp
• clippy: allow needless_option_take to report for more cases
• clippy: better help message for comparison_chain lint
• clippy: correct single_match lint suggestion
• clippy: correct suggestion for unnecessary_sort_by in no_std
• clippy: correctly handle string indices in literal_string_with_formatting_arg
• clippy: detect shadowing in pattern field
• clippy: do not suggest using Error in no_std before Rust 1.81
• clippy: fix must_use_unit suggestion when there're multiple attributes
• clippy: fix single_match lint being emitted when it should not
• clippy: initial impl of repr_packed_without_abi
• rust-analyzer: add an assist to extract an expression into a constant
• rust-analyzer: add diagnostic fix to remove unnecessary wrapper in type mismatch
• rust-analyzer: preserve order of parameters in extract_functions
• rust-analyzer: report unresolved idents for implicit captures in format_args!()
• rust-analyzer: fix publish workflow link in manual
• rust-analyzer: copied proc-macros not being cleaned up on exit
• rust-analyzer: fix a panic with a diagnostics fix when a keyword is used as a field
• rust-analyzer: fix path qualified auto-importing completions not working with re-exports
• rust-analyzer: fix proc-macro dylib names on windows
• rust-analyzer: fix sourceroot construction for virtual manifests
• rust-analyzer: generate implementation with items even if snippet text edit is disabled
• rust-analyzer: improve name suggestion for destructure_tuple_binding
• rust-analyzer: panic when displaying generic params with defaults, again
• rust-analyzer: swallow rustfmt parsing panics
• rust-analyzer: use string literal contents as a name when extracting into variable
• rust-analyzer: hash completion items to properly match them during /resolve
• rust-analyzer: properly handle different defaults for severity of lints
• rust-analyzer: show expansion errors in expand_macro feature

Rust Compiler Performance Triage

Approved RFCs

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

Tracking Issues & PRs

Rust

Cargo

Language Team

Language Reference

Unsafe Code Guidelines

New and Updated RFCs

Upcoming Events

Rusty Events between 2024-12-18 - 2025-01-15 🦀

Virtual

• 2024-12-19 | Virtual | Scandio GmBH
  • Einführung in Rust: Für eine nachhaltige Zukunft / Introduction to Rust: For a Sustainable Future
• 2024-12-19 | Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2024-12-19 | Virtual (Buenos Aires, AR) | Rust en Español
  • Despedida de Año 🎉🎉
• 2024-12-19 | Virtual (Mexico City, DF, MX) | Rust MX
  • Posada 2024
• 2024-12-20 | Virtual (Jersey City, NJ, US) | Jersey City Classy and Curious Coders Club Cooperative
  • Rust Coding / Game Dev Fridays Open Mob Session!
• 2024-12-22 | Virtual (Tel Aviv-Yafo, IL) | Rust 🦀 TLV
  • Are We Embedded Yet? - Implementing tiny HTTP server on a microcontroller
• 2024-12-24 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2024-12-26 | Virtual (Charlottesville, VA, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2025-01-02| Virtual (Berlin, DE) | OpenTechSchool Berlin + Rust Berlin
  • Rust Hack and Learn | Mirror: Rust Hack n Learn Meetup
• 2025-01-04 | Virtual (Kampala, UG) | Rust Circle Kampala
  • Rust Circle Meetup
• 2025-01-06 | Virtual (Tel Aviv-Yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • logger.info(f"Don't Give your {secrets} away") by Tamar Galer (Virtual, English)
• 2025-01-07 | Virtual (Tel Aviv-Yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • Microdosing Rust to your organization with Aviram Hassan (Virtual, English)
• 2025-01-08 | Virtual (Tel Aviv-Yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • BlockMesh Network implemented in Rust with Ohad Dahan (Virtual, English)
• 2025-01-09 | Virtual (Charlottesville, VA, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2025-01-14 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday
• 2025-01-14 | Virtual (Tel Aviv-Yafo, IL) | Code Mavens 🦀 - 🐍 - 🐪
  • An introduction to WASM in Rust with Márk Tolmács (Virtual, English)
• 2025-01-15 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Leptos

Asia

• 2025-01-12 | Virtual (Tel Aviv-Yafo, IL) | Rust 🦀 TLV
  • In person Rust January 2025 at Abra in Raanana

Europe

• 2024-12-18 | Ghent, BE | Systems Programming Ghent
  • Launch of new community for Rust and C++ developers
• 2025-01-08 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup
• 2025-01-09 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2025-01-09 | Oslo, NO | Rust Oslo
  • Rust Hack'n'Learn at Kampen Bistro

North America

• 2024-12-22 | Boston, MA, US | Boston Rust Meetup
  • Harvard Square Rust Lunch, Dec 22
• 2024-12-26 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2025-01-10 | Boston, MA, US | Boston Rust Meetup
  • Lechmere Rust Lunch, Jan 10

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

She said yes!! (And so did I!)

– Amos on Mastodon proving that Rustaceans do have a life outside of Rust. Congratulations, Amos!

Thanks to Jacob Pratt 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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Discuss on r/rust