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 1.74.0

Project/Tooling Updates

• hyper v1
• Rocket v0.5: Stable, Async, Sentinels, Streams, SSE, Forms, WebSockets, & So Much More
• GlueSQL v0.15 - Python, Redis and CSV support
• Meilisearch releases v1.5 - faster indexing, on-demand snapshots, and Puffin reports
• Nutype v0.4.0 - newtype with constraints
• Announcing open-ai-safe: a typesafe OpenAI API Rust client

Observations/Thoughts

• A JVM in Rust part 8 - Retrospective
• Rust 1.74.0: All 45 changes in 19 minutes!
• Fun with lexical analysis and Rust
• Wasmtime and Cranelift in 2023
• Signals vs. Servers
• Function interposition in Rust with upgrayedd
• A close encounter with false sharing
• Edge IoT with Rust on ESP: MQTT Publisher
• Checking semver in the presence of doc(hidden) items
• Push Ifs Up And Fors Down
• Building Segmented Logs in Rust: From Theory to Production!
• Writing an async runtime generic library
• Ferrostar: Building a Cross-Platform Navigation SDK in Rust (Part 1)

Rust Walkthroughs

• This is how I made the runtime this website runs on!
• [video] Tokenizing and parsing a programming language in Rust, by Adam Chalmers

Miscellaneous

• Building a Better Foundation for Rocket's Future
• [audio] Rust Digger with Gabor Szabo
• [video] Making the (partial) Rust BitTorrent client more reasonable
• [video] Rust Release Train 1.74
• [video] EuroRust 2023

Crate of the Week

This week's crate is rocket, an opinionated web framework that aims to be really ergonomic while still being fast.

Thanks to David Mason 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.

• Hyperswitch - [REFACTOR]: [Zen] MCA metadata validation
• Hyperswitch - [FEATURE] Standardize state field in billing and shipping address
• Hyperswitch - [BUG]: MCA metadata deserialization failures should be 4xx
• Hyperswitch - [Feature]: [NMI] Sync with Hyperswitch Reference
• Hyperswitch - [Feature]: [Zen] Sync with Hyperswitch Reference
• Ockam - Cargo.toml feature management should allow building individual crates with default feature set
• Ockam - Improve error handling of multiple ockam tcp-outlet create calls
• Ockam - Library - Slim down the NodeManagerWorker for node / tcp
• Ockam - Library - Slim down the NodeManagerWorker for node / credentials
• Ockam - Command - refactor to use typed interfaces to implement commands for secure channel and secure channel listener

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

Updates from the Rust Project

369 pull requests were merged in the last week

• add arm64e-apple-ios & arm64e-apple-darwin targets
• remove asmjs
• add -Z llvm_module_flag
• add richer structure for Stable MIR Projections
• adjust frame IP in backtraces relative to image base for SGX target
• always point at index span on index obligation failure
• avoid iterating over hashmaps in astconv
• build pre-coroutine-transform coroutine body on error
• ensure sanity of all computed ABIs
• fix insertion of statements to be executed along return edge in inlining
• handle attempts to have multiple cfgd tail expressions
• ignore but do not assume region obligations from unifying headers in negative coherence
• ignore implied bounds with placeholders
• lint pinned #[must_use] pointers (in particular, Box<T> where T is #[must_use]) in unused_must_use
• make LayoutError::Cycle carry ErrorGuaranteed
• make regionck care about placeholders in outlives components
• more detail when expecting expression but encountering bad macro argument
• new solver normalization improvements
• patterns: don't ICE when encountering a raw str slice
• recover dyn and impl after for<...>
• remove incorrect transformation from RemoveZsts
• remove legacy bitcode defaults from all Apple specs
• better handle type errors involving Self literals
• add some additional warnings for duplicated diagnostic items
• suggest dereferencing the LHS for binops such as &T == T
• on resolve error of [rest..], suggest [rest @ ..]
• try to use approximate placeholder regions when outputting an AscribeUserType error in borrowck
• when a local binding shadows a fn, point at fn def in call failure
• when encountering struct fn call literal with private fields, suggest all builders
• when using existing fn as module, don't claim it doesn't exist
• interpret: simplify handling of shifts by no longer trying to handle signed and unsigned shift amounts in the same branch
• custom MIR: Support cleanup blocks
• emit smir
• add CoroutineWitness to covered types in smir
• miri: cargo-miri: when verbose, print where the sysroot is being built
• miri: get rid of our last uses of set_var
• miri: implement all 16 AVX compare operators for 128-bit SIMD vectors
• miri: reallocarray shim linux/freebsd support proposal
• reenable effects in libcore
• if available use a Child's pidfd for kill/wait
• fix rounding issue with exponents in fmt
• add Seek::seek_relative
• impl more traits for ptr::Alignment, add mask method
• feat: implement DoubleEndedSearcher for CharArray[Ref]Searcher
• hashbrown: avoid using unstable ptr::invalid_mut
• futures: fillBuf: don't poll a second time on EOF
• futures: remove redundant impl Unpin
• cargo-credential-1password: add missing --account argument to op signin command
• cargo: add color output for cargo --list
• cargo resolver: Don't do git fetches when updating workspace members
• cargo resolver: Prefer MSRV, rather than ignore incompatible
• cargo: fix --check-cfg invocations with zero features
• cargo: fix error message for duplicate links
• cargo: handle $message_type in JSON diagnostics
• cargo: if the only path is a loop then counted as the shortest path
• cargo: ignore changing_spec_relearns_crate_types on windows-gnu
• cargo: only filter out target if its in the package root
• remove unneeded unknown variable and Symbol creation when iterating over items in rustdoc rendering
• rustdoc-search: optimize unifyFunctionTypes
• rustdoc-search: simplify the checkTypes fast path
• rustfix: fix insert at beginning
• clippy: impl_trait_in_params: avoid ICE when function with impl Trait type has no parameters
• clippy: needless_return_with_question_mark ignore let-else
• clippy: change if_same_then_else to be a style lint
• clippy: extend maybe_misused_cfg lint over cfg(test)
• clippy: manual_memcpy reduce indexing suggestions when array length is equal to loop range
• clippy: implement new lint iter_over_hash_type
• clippy: improve maybe misused cfg
• clippy: lint flatten() under lines_filter_map_ok
• clippy: new lint clippy::join_absolute_paths
• clippy: teach eager_or_lazy about panicky arithmetic operations
• clippy: verify Borrow<T> semantics for types that implement Hash, Borrow<str> and Borrow<[u8]>
• rust-analyzer: diagnose incorrect unsafety for trait impls
• rust-analyzer: diagnose missing assoc items in trait impls
• rust-analyzer: diagnose some orphan trait impl cases
• rust-analyzer: fix PathSegment grammar
• rust-analyzer: fix builtin line! expansion
• rust-analyzer: diagnose everything in nested items, not just def diagnostics
• rust-analyzer: handle default constant values in trait_impl_missing_assoc_item diagnostic

Rust Compiler Performance Triage

Pretty quiet week, with only a small number of statistically significant changes landing.

Triage done by @simulacrum. Revision range: 173b6e68..4f3da90

1 Regressions, 1 Improvements, 1 Mixed; 0 of them in rollups 60 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:

• RFC: Superseding public/private dependencies

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

• No RFCs entered Final Comment Period this week.

Tracking Issues & PRs

• [disposition: merge] [style edition 2024] Combine all delimited exprs as last argument
• [disposition: merge] Tracking Issue for ptr::addr_eq
• [disposition: merge] Stabilize C string literals
• [disposition: merge] Tracking Issue for mutex_unpoison

Language Reference

• No Language Reference RFCs entered Final Comment Period this week.

Unsafe Code Guidelines

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

New and Updated RFCs

• Macro fragment specifiers edition policy
• eRFC: Implement function delegation in rustc

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 2023-11-22 - 2023-12-20 🦀

Virtual

• 2023-11-23 | Virtual (Edmonton, AB, CA) | Edmonton R User Group - Yegrug
  • Edmonton R User Group Meetup: R and Rust, like a match made in heaven
• 2023-11-28 | Virtual (Dallas, TX, US) | Dallas Rust
  • Last Tuesday
• 2023-11-28 | Virtual (Europe / Africa) | Rust for Lunch
  • Rust Meet-up
• 2023-11-29 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • Atomics & Locks Book Club Final Chapter! (Chapter 10)
• 2023-11-30 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-11-30 | Virtual (Dublin, IE) | Rust Dublin
  • Automating expertise with cargo-semver-checks
• 2023-12-01 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • Rust & C++ Christmas Game Jam Kick-Off!
• 2023-12-02 | Virtual (Kampala, UG) | Rust Circle Kampala
  • Rust Circle Meetup
• 2023-12-05 | Virtual (Berlin, DE) | OpenTechSchool Berlin
  • Rust Hack and Learn | Mirror
• 2023-12-05 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group, First Tuesdays
• 2023-12-06 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2023-12-12 | Virtual | Mainmatter
  • Workshop: Telemetry for Rust applications
• 2023-12-12 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2023-12-14 | Virtual (Nuremberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2023-12-18 | Virtual (Munich, DE) | Rust Munich
  • Rust Munich 2023 / 5 - hybrid
• 2023-12-20 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out

Europe

• 2023-11-23 | Biel/Bienne, CH | Rust Bern
  • Rust Talks Bern @ Biel: Embedded Edition
• 2023-11-28 | London, UK | Rust London User Group
  • LDN Talks November 2023 with Helsing.ai
• 2023-11-30 | Brussels, BE | Belgium Rust user group
  • Lambda Brussels
• 2023-11-30 | Copenhagen, DK | Copenhagen Rust Community
  • Rust metup #42 sponsored by Nine A/S
• 2023-11-30 | Vienna, AT | Rust Vienna
  • Rust Vienna Meetup - November
• 2023-11-30 | Zurich, CH| Rust Zurich
  • November Meetup
• 2023-12-06 | Cologne, DE | Rust Cologne
  • December Meetup
• 2023-12-07 | Aarhus, DK | Rust Aarhus
  • Rust and Talk at Danske Commodities
• 2023-12-07 | Lille, FR | Rust Lille
  • Rust Lille #5
• 2023-12-14 | Augsburg, DE | Rust - Modern Systems Programming in Leipzig
  • Augsburg Rust Meetup #4
• 2023-12-18 | Munich, DE + Virtual | Rust Munich
  • Rust Munich 2023 / 5 - hybrid
• 2023-12-19 | Leipzig, DE | Rust - Modern Systems Programming in Leipzig
  • Tauri, an Electron-alternative

North America

• 2023-11-22 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2023-11-28 | Pasadena, CA, US | Pasadena Thursday Go / Rust
  • Monthly Rust group
• 2023-11-29 | Chicago, IL, US | Deep Dish Rust
  • Rust Hack Night
• 2023-12-12 | Seattle, WA, US | Cap Hill Rust Coding/Hacking/Learning
  • Rusty Coding/Hacking/Learning Night
• 2023-12-19 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person

Oceania

• 2023-11-28 | Canberra, ACT, AU | Rust Canberra
  • November Meetup
• 2023-12-05 | Aukland, NZ | Rust AKL
  • Rust AKL: Advanced Async Tricks + Interruptible Software
• 2023-12-11 | Perth, WA, AU | Rust Perth Meetup Group
  • Rust End of Year Event

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

If you require it, measure it. That's the simple answer. Everything else is guesswork.

– Johannes Lade on rust-users

Thanks to Michael Bryan 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