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

• A tale of broken badges and 23,000 features
• crates.io: Dropping support for non-canonical downloads
• Generators are dead, long live coroutines, generators are back

Project/Tooling Updates

• ratatui 0.24.0 is released! (Rust library that's all about cooking up terminal user interfaces)
• git-cliff 1.4.0 is released! (highly customizable changelog generator)
• rust-analyzer changelog #205
• Progress report on rustc_codegen_cranelift (Oct 2023)

Observations/Thoughts

• System dependencies are hard (so we made them easier)
• Was Rust Worth It?
• Can Rust prevent logic errors?
• Faster Rust Serialization
• Dealing with Dependencies in Rust
• How I learned to stop worrying and love byte ordering
• How To Move Fast With Rust
• Starting a virtual Rust meet-up
• [video] Impl Trait aka Look ma’, no generics! by Jon Gjengset

Rust Walkthroughs

• Fully Automated Releases for Rust Projects
• The beauty of a Rust message processor
• interrupts is threads
• htmx, Rust & Shuttle: A New Rapid Prototyping Stack
• [video] Async Not Required 🦀

Research

• Functional Ownership through Fractional Uniqueness
• Grading on a Curve: How Rust can Facilitate New Contributors while Decreasing Vulnerabilities

Miscellaneous

• [video] 5 Hours to 7.7 Seconds: How Database Tricks Sped up Rust Linting Over 2000x

Crate of the Week

This week's crate is silkenweb, a library for building web apps with fine-grained reactivity and a clean separation of logic and UI.

Thanks to henrik for the 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.

• pubgrub - Move to edition 2021
• pubgrub - Fix CI for conventional commits
• pubgrub - Rename v0.3 Range into BoundedRange
• pubgrub - OfflineDependencyProvider should get its own module
• Ockam - Library - Slim down the NodeManagerWorker for node / tcp
• Ockam - Make ockam vault delete (no args) interactive by asking the user to choose from a list of vaults to delete (tuify)
• Ockam - Command - refactor to use typed interfaces to implement commands for services

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

Updates from the Rust Project

408 pull requests were merged in the last week

• -Zunpretty help: add missing possible values
• NVPTX: allow PassMode::Direct for ptx kernels for now
• OptWithInfcx naming nits, trait bound simplifications
• deduce_param_attrs: explain a read-only case
• rustc_interface cleanups
• stack_overflow: get_stackp using MAP_STACK flag on dragonflybsd too
• add bootstrap flag --skip-stage0-validation
• add method to convert internal to stable constructs
• add support for i586-unknown-netbsd as target
• add support for mipsel-unknown-netbsd, 32-bit LE mips
• add target features for LoongArch
• add way to differentiate argument locals from other locals in Stable MIR
• allow partially moved values in match
• allow target specs to use an LLD flavor, and self-contained linking components
• allows #[diagnostic::on_unimplemented] attributes to have multiple
• avoid repeated interning of env!("CFG_RELEASE")
• avoid unbounded O(n^2) when parsing nested type args
• avoid unnecessary builds/rebuilds of rust-demangler
• avoid unnecessary renumbering during borrowck
• c-variadic error improvements
• consider alias bounds when computing liveness in NLL (but this time sound hopefully)
• const stabilize mem::discriminant
• correctly handle nested or-patterns in exhaustiveness
• coverage: consistently remove unused counter IDs from expressions/mappings
• coverage: replace manual debug indents with nested tracing spans in counters
• create windows/api.rs for safer FFI
• create a new ConstantKind variant (ZeroSized) for StableMIR
• declare rustc_target's dependency on object/macho
• deny providing explicit effect params
• derive Ord, PartialOrd and Hash for SocketAddr*
• detect when trait is implemented for type and suggest importing it
• do not suggest 'Trait<Assoc=arg>' when in trait impl
• don't normalize to an un-revealed opaque when we hit the recursion limit
• don't treat closures/coroutine types as part of the public API
• don't use LFS64 symbols on musl
• eat close paren if capture_cfg to avoid unbalanced parens
• enable cg_clif tests for riscv64gc
• fail typeck for illegal break-with-value
• fix ICE: Restrict param constraint suggestion
• fix failure to detect a too-big-type after adding padding
• fix inline const pattern unsafety checking in THIR
• fix missing leading space in suggestion
• fix unused variables lint issue for args in macro
• fix unwrap suggestion for async fn
• generate aggregate constants in DataflowConstProp
• handle ReErased in responses in new solver
• ignore RPIT duplicated lifetimes in opaque_types_defined_by
• implement C ABI lowering for CSKY
• implement gen blocks in the 2024 edition
• improve android-ndk property interface
• improve some diagnostics around ?Trait bounds
• improve the warning messages for the #[diagnostic::on_unimplemented]
• increase the reach of panic_immediate_abort
• intern LocalDefId list from opaque_types_defined_by query
• introduce -C instrument-coverage=branch to gate branch coverage
• invalid ? suggestion on mismatched Ok(T)
• lint overlapping ranges as a separate pass
• mark .rmeta files as /SAFESEH on x86 Windows
• mark constructor of BinaryHeap as const fn
• never consider raw pointer casts to be trival
• on object safety error, mention new enum as alternative
• on unresolved imports, suggest a disambiguated path if necessary to avoid collision with local items
• only call mir_const_qualif if absolutely necessary
• only emit one error per unsized binding, instead of one per usage
• poison check_well_formed if method receivers are invalid to prevent typeck from running on it
• print variadic argument pattern in HIR pretty printer
• properly restore snapshot when failing to recover parsing ternary
• quietly fail if an error has already occurred
• rand use getrandom for freebsd (available since 12.x)
• refactor type visitor walking
• remap Cargo dependencies to /rust/deps
• remove -Zdep-tasks
• remove Apple RNG fallbacks and simplify implementation
• remove fold code and add Const::internal() to StableMIR
• remove support for alias -Z instrument-coverage
• require target features to match exactly during inlining
• return multiple object-safety violation errors and code improvements to the object-safety check
• return unfixed len if pat has reported error
• rework negative coherence to properly consider impls that only partly overlap
• rustdoc: elide cross-crate default generic arguments
• rustdoc: use ThinVec in GenericParamDefKind
• see through aggregates in GVN
• separate move path tracking between borrowck and drop elaboration
• share some track_caller logic between interpret and codegen
• small ty::print cleanups
• some diagnostics improvements of gen blocks
• stash and cancel cycle errors for auto trait leakage in opaques
• stop telling people to submit bugs for internal feature ICEs
• store #[stable] attribute's since value in structured form
• suggest assoc fn new when trying to build tuple struct with private fields
• suggest unwrap/expect for let binding type mismatch
• tvOS simulator support on Apple Silicon for rustc
• tweak suggestion span for outer attr and point at item following invalid inner attr
• uplift Canonical to rustc_type_ir
• uplift ClauseKind and PredicateKind into rustc_type_ir
• use ImageDataType for allocation type
• validate feature and since values inside #[stable(…)]
• when encountering sealed traits, point types that implement it
• when expecting closure argument but finding block provide suggestion
• work around the fact that check_mod_type_wf may spuriously return ErrorGuaranteed
• time: use clock_gettime on macos
• windows: support sub-millisecond sleep
• refactor some char, u8 ASCII functions to be branchless
• add #[inline] to some recalcitrant ops::range methods
• stabilize ratified RISC-V Target Features
• stabilize [const_]pointer_byte_offsets
• stabilize inline asm usage with rustc_codegen_cranelift
• futures: add TryAll and TryAny adapters
• futures: fix Sync impl of FuturesUnordered
• futures: provide AtomicWaker if portable-atomic feature is enabled, even if atomic CAS is not available
• codegen_gcc: add basics for test command in build system
• codegen_gcc: fix volatile_load
• cargo toml: Allow version-less manifests
• cargo toml: Decouple parsing from interning system
• cargo: shell: Write at once rather than in fragments
• cargo: add new packages to [workspace.members] automatically
• cargo: move up looking at index summary enum
• cargo: remove duplicate binaries during install
• cargo: remove outdated option to -Zcheck-cfg warnings
• rustfmt: fixed error caused by combination of match_arm_blocks and control_brace_style
• clippy: ignored_unit_patterns: check &(), &&(),
• clippy: iter_without_into_iter: fix papercuts in suggestion and restrict linting to exported types
• clippy: let_and_return: Wrap with parenthesis if necessary
• clippy: add waker_clone_and_wake lint to check needless Waker clones
• clippy: fix missing parenthesis in suboptimal floating point help
• clippy: ignore lower-camel-case words in doc_markdown
• clippy: move read_zero_byte_vec to nursery
• clippy: remove internal feature from clippy_utils
• clippy: remove the internal_warn lint category
• rust-analyzer: make extract_variable assist in place

Rust Compiler Performance Triage

This week we have two sets of results as last week's arrived later than the publish date:

Triage done by @rylev and @simulacrum.

Revision range: b9832e72..650991d

Across both reports:

9 Regressions, 7 Improvements, 5 Mixed 127 artifact comparisons made in total

• Full report #1
• Full report #2

Approved RFCs

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

• 2024 Edition

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] Lifetime Capture Rules 2024
• [disposition: merge] Add "crates.io Policy Update" RFC

Tracking Issues & PRs

• [disposition: merge] Override Waker::clone_from to avoid cloning Wakers unnecessarily
• [disposition: merge] dropck_outlives check whether generator witness needs_drop
• [disposition: merge] stricter hidden type wf-check
• [disposition: merge] Tracking Issue for the GroupBy and GroupByMut iterators
• [disposition: merge] Don't panic in <BorrowedCursor as io::Write>::write
• [disposition: merge] Guarantee that char has the same size and alignment as u32
• [disposition: merge] Stabilize const_maybe_uninit_zeroed and const_mem_zeroed
• [disposition: merge] Clarify UB in get_unchecked(_mut)
• [disposition: merge] document that the null pointer has the 0 address
• [disposition: close] regression: parameter type may not live long enough

Language Reference

• [disposition: merge] Guarantee that raw pointer conversions preserve slice element count

Unsafe Code Guidelines

• No Unsafe Code Guideline RFCs entered Final Comment Period this week.

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:

• 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 2023-11-01 - 2023-11-29 🦀

Virtual

• 2023-11-01 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • ECS with Bevy Game Engine
• 2023-11-01 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2023-11-02 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-11-07 | Virtual (Berlin, DE) | OpenTechSchool Berlin
  • Rust Hack and Learn | Mirror
• 2023-11-07 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group, First Tuesdays
• 2023-11-09 | Virtual (Nuremberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2023-11-14 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2023-11-15 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • Building Our Own Locks (Atomics & Locks Chapter 9)
• 2023-11-15 | Virtual (Richmond, VA, US) | Linux Plumbers Conference
  • Rust Microconference in LPC 2023 (Nov 13-16)
• 2023-11-15 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Nightly Night: impl Trait in Type Aliases
• 2023-11-16 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-11-21 | Virtual (Berlin, DE) | OpenTechSchool Berlin
  • Rust Hack and Learn
• 2023-11-21 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2023-11-28 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday

Europe

• 2023-11-01 | Cologne, DE | Rust Cologne
  • Web-applications with axum: Hello CRUD!
• 2023-11-07 | Bratislava, SK | Bratislava Rust Meetup Group
  • Rust Meetup by Sonalake
• 2023-11-07 | Aarhus, DK | Rust Aarhus
  • Rust Aarhus - Rust and Talk beginners edition
• 2023-11-07 | Lyon, FR | Rust Lyon
  • Rust Lyon Meetup #7
• 2023-11-09 | Barcelona, ES | BcnRust
  • 11th BcnRust Meetup
• 2023-11-09 | Paris, FR | Paris Rustaceans
  • Rust Meetup in Paris
• 2023-11-09 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup at Browns
• 2023-11-21 | Leipzig, DE | Rust - Modern Systems Programming in Leipzig
  • GPU processing in Rust
• 2023-11-23 | Biel/Bienne, CH | Rust Bern
  • Rust Talks Bern @ Biel: Embedded Edition

North America

• 2023-11-01 | Brookline, MA, US | Boston Rust Meetup
  • Boston Common Rust Lunch
• 2023-11-02 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2023-11-08 | Boulder, CO, US | Boulder Rust Meetup
  • Let's make a Discord bot!
• 2023-11-14 | New York, NY, US | Rust NYC
  • Rust NYC Monthly Mixer: Share, Show, & Tell! 🦀
• 2023-11-14 | Seattle, WA, US | Cap Hill Rust Coding/Hacking/Learning
  • Rusty Coding/Hacking/Learning Night
• 2023-11-15 | Richmond, VA, US + Virtual | Linux Plumbers Conference
  • Rust Microconference in LPC 2023 (Nov 13-16)
• 2023-11-16 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2023-11-16 | Nashville, TN, US | Music City Rust Developers
  • Python loves Rust!
• 2023-11-16 | Seattle, WA, US | Seattle Rust User Group
  • Seattle Rust User Group Meetup
• 2023-11-21 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2023-11-22 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground

Oceania

• 2023-11-06 | Perth, WA, AU | Rust Perth Meetup Group
  • Embracing Lifetimes: A Journey to Safe and Efficient Code
• 2023-11-21 | Christchurch, NZ | Christchurch Rust Meetup Group
  • Christchurch Rust meetup meeting
• 2023-11-28 | Canberra, ACT, AU | Rust Canberra
  • November 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

After doing a best fit, we found Rust projects were less likely to introduce vulnerabilities than their equivalent C++ projects at all relevant experience levels, but more importantly, we found the effect was most significant for first-time contributors, who were almost two orders of magnitude less likely to contribute vulnerabilities. That is, even though Rust may have a reputation as a harder language to learn, there is a very measurable effect that makes it better for newbies. Reviewers should not have to put as much effort into reviewing code to be confident that someone making their first foray into their project is accidentally adding a vulnerability.

– Justin Tracey on crysp.org

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.

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust