This Week In Rust: This Week in Rust 661

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.bsky.social on Bluesky 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

• Announcing Rust 1.97.1

Newsletters

• The Embedded Rustacean Issue #76

Project/Tooling Updates

• Announcing Topcoat: a framework for building full-stack reactive web apps with Rust
• Syn 3.0.0
• What’s New in RustRover 2026.2
• kobe 0.35.0: readiness gates and cert recycling
• Comhad v0.1.0: a ranger-style tui cyberduck replacement for browsing S3
• Nova v0.2.1: computer-use MCP server
• winit now has comprehensive cross-platform drag-and-drop support, exposing most of the power of the underlying OS APIs
• crimson-crab v0.1.0 - a production-grade Rust SDK for the Claude API (streaming, tool use, prompt caching, batches)
• ferrovec: dependency-light HNSW vector search in Rust, compiled to WebAssembly for private in-browser semantic search
• OrdoFP 0.1.0 released — a functional-programming toolbelt for Rust (HList, GAT type classes, optics, effects, monad transformers)
• Freya 0.4
• buildline: merging cargo and ninja's build profiling into one timeline
• cochlea 0.3.0: melody read-back, MFCC timbre, a master limiter, and MIDI import for the deterministic agent-audio engine
• flodl 0.6.0: multi-host heterogeneous DDP - mismatched GPUs across hosts beat the fastest card alone
• hwatu: a daemon-based WebKitGTK browser for tiling WMs with ~13ms window spawn
• kache 0.11.0: broader compiler coverage and libc-aware keys
• tracing-reload - reload layer without panics
• Introducing OpenTypeless: Voice Input That Actually Works
• Reading a Rust crate's capabilities out of its compiled symbols

Observations/Thoughts

• Battery packs: Let's talk about crates, baby
• Capture Clauses as Effects
• Hardening Rust Code For Production
• Tokio Gives Progress, Not Ordering: Scheduling 1M Tasks
• Rust service hardening and production checklist
• [audio] The Rust Foundation with Rebecca Rumbul, Lori Lorusso, and David Wood, Rust Foundation leadership and board
• [video] Jon Gjengset: Open Source Maintenance 2026-07-18
• [video] Rust Release Changelog - 1.97.0
• [video] Livestream: Rust in Ubuntu

Rust Walkthroughs

• I hash-chained my agent's audit log. Then I found 13 breaks in it — all mine, all benign.
• Two tricky bugs in a Rust daemon
• [video] Backend Concepts in Rust: Securely Managing App Secrets
• [video] Build with Naz - Ep 21: High Performance Flat 2D Arrays in Rust (SIMD, L1 cache)

Crate of the Week

This week's crate is xan, a TUI toolkit to work with CSV files.

Thanks to Simeon H.K. Fitch 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.

If you are a feature implementer and would like your RFC to appear in this list, add a 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.

No calls for testing were issued this week by Rust, Cargo, Rustup or Rust language RFCs.

Let us know if you would like your feature to be tracked as a part of this list.

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 or by reaching out on Bluesky 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.

• 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 or by reaching out on Bluesky or Mastodon!

Updates from the Rust Project

576 pull requests were merged in the last week

Compiler

• account for async closures when pointing at lifetime in return type
• comptime inherent impls
• dep_graph: deduplicate task reads with an epoch-filtered index recorder
• eagerly check for ambiguity in macro parsing
• implement #[diagnostic::opaque] attribute to hide backtraces of macros
• shrink ast::Expr64

Library

• add explicit Iterator::count impl for str::EncodeUtf16
• implement bool::toggle
• implement const_binary_search
• implement Debug helpers via Cell
• implement VecDeque::truncate_to_range
• make pin!() more foolproof
• move std::io::BufRead to alloc::io
• move std::io::Read to alloc::io
• move std::io::read_to_string to alloc::io

Cargo

• use PGO for Cargo
• timings: only report units the job queue actually ran
• do not include proc-macro deps in rustc search path args
• include SBOM outputs in fingerprints
• lazily initialize git2 fetch transports

Rustdoc

• fix auto trait normalization env
• use PGO for rustdoc

Clippy

• add block_scrutinee lint
• avoid invalid ref_as_ptr suggestions in const/static initializers
• detect == 0 on unsigned types as a manual_clamp lower bound
• fix if_not_else linting on macro expanded conditions
• fix needless_collect suggests a suggestion that cannot be typed
• non_zero_suggestions: don't lint signed integer div/rem as NonZero
• manual_filter: don't eat comments in the and_then suggestion
• require the use of as _ for indirectly used traits in clippy sources
• rewrite min_ident_chars
• use #[must_use] determination from the compiler

Rust-Analyzer

• avoid index panic when flycheck list is empty
• add capture hints to coroutines
• add handler for E0572
• do not assume array destructuring assignments with rest pattern are constant-sized
• eagerly normalize .await's IntoFuture::Output
• enable auto trait inference
• extract variable preserving whitespace from macro input
• fix coroutines not recording binding owners correctly
• fix crashes in assists due to .unwrap() calls in SyntaxFactory
• fix hir crate leaking bound variables from skipped binders
• fix InferenceContext:identity_args using the wrong DefId
• fix syntax bridge panic when spilting float
• handle enum variants in next-solver generics
• implement lowering of HRTB
• invalid pattern_matching_variant lowering due to recovery
• merge WherePredicate::ForLifetimes into WherePredicate::TypeBound
• only write anon const ty in parent's inference result if it doesn't have its own inference
• panic with a function item and a proc macro item having a duplicate name
• parser to error on macro type bound
• spawn proc-macro servers on requests clearing the client cache
• use quote! inside ast::make::expr_call()
• use Result for the lsp-server Response payload type
• record expressions in types in ExprScope

Rust Compiler Performance Triage

The two most notable changes this week were #159115, which resulted in pretty nice instruction count wins for full incremental builds on several benchmarks, and #159091, which enabled PGO for rustdoc, which makes it ~3-4% faster across the board.

There were two large rollups with tiny performance regressions, which made it difficult to find the offending PRs.

Triage done by @Kobzol. Revision range: 5503df87..d527bc9b

Summary:

(instructions:u)	mean	range	count
Regressions ❌ (primary)	0.4%	[0.2%, 1.0%]	40
Regressions ❌ (secondary)	0.7%	[0.2%, 4.6%]	69
Improvements ✅ (primary)	-2.0%	[-6.2%, -0.2%]	136
Improvements ✅ (secondary)	-2.6%	[-8.4%, -0.2%]	119
All ❌✅ (primary)	-1.4%	[-6.2%, 1.0%]	176

2 Regressions, 3 Improvements, 6 Mixed; 4 of them in rollups 34 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.

Tracking Issues & PRs

Rust

• Tracking Issue for bool::toggle
• Tracking Issue for vec_try_remove
• Avoid computing layout of enums with non-int discriminants
• Tracking Issue for const_btree_len
• Add raw_borrows_via_references lint
• stabilize size_of_val_raw, align_of_val_raw, Layout::for_value_raw
• rustc_passes: lint unused #[path] attributes on inline modules

Compiler Team (MCPs only)

• Emit note when calling rustc without specifying an edition
• Let the OS handle stack growth
• Add target_feature_available_at_call_site

Leadership Council

• Deallocate post-2026 funds from PM and compiler-ops

Unsafe Code Guidelines

• Do the bytes of a pointer have to stay in the same order?

No Items entered Final Comment Period this week for Cargo, Language Reference, Language Team or Rust RFCs.

Let us know if you would like your PRs, Tracking Issues or RFCs to be tracked as a part of this list.

New and Updated RFCs

• RFC: Refactor the libs team

Upcoming Events

Rusty Events between 2026-07-22 - 2026-08-19 🦀

Virtual

• 2026-07-24 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-07-28 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Fourth Tuesday
• 2026-07-28 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2026-07-30 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 2026-07-31 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-08-01 | Virtual (Kampala, UG) | Rust Circle Meetup
  • Rust Circle Meetup
• 2026-08-02 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Rust Deep Learning: First Sunday
• 2026-08-04 | Virtual (London, UK) | Women in Rust
  • 👋 Community Catch Up
• 2026-08-05 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2026-08-07 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-08-11 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
  • Second Tuesday
• 2026-08-13 | Virtual (Berlin, DE) | Rust Berlin
  • Rust Hack and Learn
• 2026-08-13 | Virtual (Nürnberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2026-08-14 | Virtual (Girona, ES) | Rust Girona
  • Sessió setmanal de codificació / Weekly coding session
• 2026-08-18 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2026-08-19 | Hybrid (Vancouver, BC, CA) | Vancouver Rust
  • Dealing with Dependencies

Africa

• 2026-08-11 | Johannesburg, ZA | Johannesburg Rust Meetup
  • Rust's extended standard library

Asia

• 2026-07-25 | Mumbai, IN | Rust Mumbai
  • ​Rust Mumbai — July Meetup 🦀
• 2026-07-26 | Pune, IN | Rust Pune
  • Rust Pune: July 2026

Europe

• 2026-07-23 | Berlin, DE | Rust Berlin
  • Rust Berlin Talks: The next generation
• 2026-07-23 | London, UK | Rust London User Group
  • LDN Talks: July 2026 Antithesis Takeover
• 2026-07-23 | London, UK | London Rust Project Group
  • Rama modular service framework for Rust
• 2026-07-23 | Paris, FR | Rust Paris
  • Rust meetup #87
• 2026-07-25 | Stockholm, SE | Stockholm Rust
  • Ferris' Fika Forum #28
• 2026-07-27 | Augsburg, DE | Rust Meetup Augsburg
  • Rust Meetup #20: Julian Dickert - Supply chain security in Rust: Evaluating crates for production
• 2026-07-29 | Poland, PL | Rust Poland
  • Rust Poland x Kraków #10
• 2026-07-30 | Copenhagen, DK | Copenhagen Rust Community
  • Rust meetup #70
• 2026-07-30 | Manchester, UK | Rust Manchester
  • Rust Manchester July Code Night
• 2026-08-18 | Aarhus, DK | Rust Aarhus
  • Hack Night: Trust but verify the LLM
• 2026-08-18 | Leipzig, DE | Rust - Modern Systems Programming in Leipzig
  • Topic TBD

North America

• 2026-07-22 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground
• 2026-07-22 | Los Angeles, CA, US | Rust Los Angeles
  • Rust LA: Rust in Distributed Systems with Flight Science!
• 2026-07-22 | New York, NY, US | Rust NYC
  • Rust NYC: Write A Custom Coding Agent and wasm_zero
• 2026-07-23 | Mountain View, CA, US | Hacker Dojo
  • RUST MEETUP at HACKER DOJO
• 2026-07-25 | Boston, MA, US | Boston Rust Meetup
  • Porter Square Rust Lunch, July 25
• 2026-07-25 | Brooklyn, NY, US | Flower
  • BOG-A-THON 2
• 2026-07-30 | Atlanta, GA, US | Rust Atlanta
  • Rust-Atl
• 2026-08-01 | Boston, MA, US | Boston Rust Meetup
  • Chinatown Rust Lunch, Aug 1
• 2026-08-04 | Boston, MA, US | Boston Rust Meetup
  • Evening Boston Rust Meetup at Red Hat, Aug 4
• 2026-08-06 | Saint Louis, MO, US | STL Rust
  • Shipping Temporal: How a Global Rust Ecosystem Built Chrome’s Newest Web API
• 2026-08-13 | Lehi, UT, US | Utah Rust
  • Utah Rust August Meetup
• 2026-08-13 | San Diego, CA, US | San Diego Rust
  • San Diego Rust August Meetup - Back in person!
• 2026-08-15 | San Francisco, CA, US | Flower
  • BOG-A-THON 3
• 2026-08-18 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2026-08-19 | Hybrid (Vancouver, BC, CA) | Vancouver Rust
  • Dealing with Dependencies

Oceania

• 2026-07-23 | Perth, AU | Rust Perth Meetup Group
  • Rust Perth: July Meetup!
• 2026-07-30 | Melbourne, AU | Rust Melbourne
  • Rust Melbourne July 2026

South America

• 2026-08-08 | São Paulo, SP | Rust-SP
  • Rust SP - Aug/2026

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

We were planning on publishing a blog post announcing this at the same time as making the repo public, but ran out of private repo CI usage 😭.

– Carl Lerche on r/rust about the launch of topcoat

Despite a lamentable lack of suggestions, llogiq is glad to have found this quote.

Please submit quotes and vote for next week!

This Week in Rust is edited by:

• nellshamrell
• llogiq
• ericseppanen
• extrawurst
• U007D
• mariannegoldin
• bdillo
• opeolluwa
• bnchi
• KannanPalani57
• tzilist

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust