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

• crates.io Postmortem: Broken Crate Downloads
• July 2023 Leadership Council Update

Foundation

• My first three months at the Rust Foundation

Project/Tooling Updates

• IntelliJ Rust Changelog #199
• Fyrox Game Engine 0.31
• Writing a Rest HTTP Service with Axum

Observations/Thoughts

• Totality
• Why the “Null” Lifetime Does Not Exist
• First report: More than 80% of the crates link to their public VCS
• [video] Aram Drevekenin – Zellij - A terminal workspace with batteries included

Rust Walkthroughs

• Make invalid states unrepresentable
• A visual tree iterator in Rust
• A gentle introduction to IMAP
• ESP32 Standard Library Embedded Rust: UART Communication
• Shuttle Launchpad #3: Sudoku, Ownership and Error Handling
• [video] Pragmatic Intro to Rust Web Development: Overview

Research

• ResourceGauge: Enabling Resource-Aware Software Components (with Rust)

Miscellaneous

• How to speed up the Rust compiler: data analysis assistance requested!
• Programming language popularity: Rust
• Llama2.rs - Inference Llama 2 in one file of pure Rust

Crate of the Week

This week's crate is tower-async, a currently nightly-only async library to build network servers, based on tower.

Thanks to Glen De Cauwsemaecker for the self-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.

• Ockam - Investigate if the macOS toggle is possible in system tray app build with Tauri
• Ockam - Avoid setting an embedded node as default for ockam project enroll
• Ockam - ockam project ticket should return a proper error message
• Hyperswitch - Migrate to enum_dispatch to reduce runtime overhead
• Hyperswitch - Add Create Merchant and Create Merchant Key Store in a DB transaction
• Hyperswitch - Use proxy exclusion instead of a separate proxied client
• Hyperswitch - Add scoped error enum for customer error

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

Updates from the Rust Project

406 pull requests were merged in the last week

• add mips64r6 and mips32r6 as target_arch values
• add riscv64gc-unknown-hermit target
• add x86_64-unknown-linux-ohos target
• enable chkstk/alloca intrinsics on x86_64-unknown-uefi
• Support .comment section like GCC/Clang (!llvm.ident)
• add Alias to smir
• add BITS, from_bits, to_bits to IP addresses
• add FnPtr ty to SMIR
• add Foreign, Never, FnDef, Closure and Generator tys to SMIR
• add #[inline] to core debug assertion helpers
• add dynamic for smir
• add the no-builtins attribute to functions when no_builtins is applied at the crate level
• add ty convs for smir refs and ptrs
• allow opaques to be defined by trait queries, again
• always const-prop scalars and scalar pairs
• avoid tls access while iterating through mpsc thread entries
• better diagnostics for dlltool errors
• comment stuff in the new solver
• don't translate compiler-internal bug messages
• encode shorthands for spans in metadata
• error/E0691: include alignment in error message
• fix #[inline(always)] on closures with target feature 1.1
• fix inline_const with interpolated block
• fix invalid display of inlined re-export when both local and foreign items are inlined
• fix removal span calculation of unused_qualifications suggestion
• fix results search alias display
• fix rustc-args passing issue in bootstrap
• get !nonnull metadata on slice iterators, without assumes
• get rid of subst-relate incompleteness in new solver
• improve error message when closing bracket interpreted as formatting fill character
• inline overlap based CGU merging
• lint/ctypes: only try normalize
• new solver: add a separate cache for coherence
• new solver: don't consider blanket impls multiple times
• on nightly, dump ICE backtraces to disk
• permit pre-evaluated constants in simd_shuffle
• prototype: add unstable -Z reference-niches option
• querify unused trait check
• refactor vtable encoding and optimize it for the case of multiple marker traits
• remove Scope::Elision from bound-vars resolution
• rename arg_iter to iter_instantiated
• restrict recursive opaque type check
• resurrect: rustc_llvm: Add a -Z print-codegen-stats option to expose LLVM statistics
• reuse codegen_ssa monomorphization errors in codegen_gcc
• reuse the MIR validator for MIR inlining
• revert "Prototype: Add unstable -Z reference-niches option"
• safe Transmute: Fix ICE (due to UnevaluatedConst)
• substitute types before checking inlining compatibility
• support --print KIND=PATH command line syntax
• support interpolated block for try and async
• turn copy into moves during DSE
• tweak spans for self arg, fix borrow suggestion for signature mismatch
• use SHA256 source file checksums by default when targeting MSVC
• use features() over features_untracked() where possible
• use erased self type when autoderefing for trait error suggestion
• use the correct span for displaying the line following a derive sugge…
• miri: make full field retagging the default
• remove redundant clones
• fix size_hint for EncodeUtf16
• allow limited access to OsString bytes
• make {Rc,Arc}::allocator associated functions
• stabilize chown functions (unix_chown)
• remove an allocation in Path::with_extension
• remove the unstable core::sync::atomic::ATOMIC_*_INIT constants
• remove lifetime bound for A for impl Extend<&'a T> for Vec<T, A>
• hashbrown: publicly re-export Equivalent from the crate root
• futures: add TryStreamExt::try_ready_chunks as failable version of StreamExt::ready_chunks
• codegen_gcc: add instructions on how to generate GIMPLE format
• codegen_gcc: add support for "ffi_const" function attribute
• cargo: git: respect scp-like URL for nested submodules
• cargo: credential provider implementation
• cargo: fix "cargo doc --open" crash on WSL2
• cargo: fix: encode URL params correctly for SourceId in Cargo.lock
• cargo: fix: only skip mtime check on ~/.cargo/{git,registry}
• rustdoc: strip impl if not re-exported and is doc(hidden)
• rustdoc: fix position of default in method rendering
• rustdoc: handle cross-crate RPITITs correctly
• clippy: significant_drop_tightening don't lint literal-returning functions
• clippy: significant_drop_tightening fix tuple drop recognition
• clippy: inherent_to_string: Don't lint unsafe or extern fns
• clippy: manual_filter_map: lint on matches and pattern matching
• clippy: ptr_arg should ignore extern functions
• clippy: redundant_pattern_matching: include guard in suggestion
• clippy: unnecessary_literal_unwrap: fix ICE on None.unwrap_or_default()
• clippy: unused_async: don't lint if paths reference async fn without immediate call
• clippy: unwrap_or_else_default → unwrap_or_default and improve resulting lint
• clippy: allow Self::cmp(self, other) as a correct impl
• clippy: check for fully qualified paths in unnecessary_cast
• clippy: check that the types are equal in SpanlessEq::eq_expr
• clippy: fix unwrap_or_else_default false positive
• clippy: fix async functions handling for needless_pass_by_ref_mut lint
• clippy: fix: false positive for option_env! in ifs_same_cond
• clippy: make comparison_to_empty work on if let/let chains
• clippy: new lints: absolute_paths, error_impl_error, four_forward_slashes, iter_skip_zero, needless_return_with_try, redundant_guards, string_lit_chars_any, redundant_locals
• clippy: refactor some of dereference.rs to util functions
• clippy: remove #![allow(unused)] and --crate-name from cargo dev new_lint generated tests
• clippy: rewrite tuple_array_conversions
• rust-analyzer: editor/code: Use notification command links for debugger installation
• rust-analyzer: fix highlighting of byte escape sequences
• rust-analyzer: fix: don't follow raw pointer derefs when considering method receiver candidates
• rust-analyzer: fix: lookup super traits in is_dyn_method
• rust-analyzer: fix: normalize expected ty in call arguments
• rust-analyzer: fix: report incorrect-ident-case for inner items
• rust-analyzer: limit change_visibility assist to applicable items
• rustfmt: prevent ICE when formatting an empty-ish macro arm
• rustfmt: support non-lifetime binders

Rust Compiler Performance Triage

A relatively light week with respect to performance changes. The one major regressing PR was reverted (for other reasons), and we saw some very nice gains on compile-times from (1.) changes to our codegen-unit merging logic and from (2.) changes to the stdlib slice iterators encoding its non-null guarantees directly, allowing the removal of a call to the assume intrinsic.

Triage done by @pnkfelix. Revision range: 6b9236ed..0308df23

1 Regressions, 1 Improvements, 4 Mixed; 1 of them in rollups 35 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.

RFCs

• No RFCs entered Final Comment Period this week.

Tracking Issues & PRs

• [disposition: merge] make noop_method_call warn by default
• [disposition: merge] Infer type in irrefutable slice patterns with fixed length as array

New and Updated RFCs

• [new] Add "crates.io Policy Update" RFC
• [new] RFC: Generic member access for dyn Error trait objects
• [new] Error Display (std::error::Error::fmt_error)

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 2023-07-26 - 2023-08-23 🦀

Virtual

• 2023-07-26 | Virtual (Cardiff, UK)| Rust and C++ Cardiff
  • The unreasonable power of combinator APIs
• 2023-07-27 | Virtual (Charlottesville, NC, US) | Charlottesville Rust Meetup
  • Crafting Interpreters in Rust Collaboratively
• 2023-07-28 | Virtual (Tunis, TN) | Rust Meetup Tunisia
  • Rust Meetup Tunisia - Volume I, Number IV
• 2023-07-31 | Virtual (Linz, AT) | Rust Linz
  • Rust Meetup Linz - 31st Edition
• 2023-08-01 | Virtual (Berlin, DE) | OpenTechSchool Berlin
  • Rust Hack and Learn
• 2023-08-01 | Virtual (Buffalo, NY, US) | Buffalo Rust Meetup
  • Buffalo Rust User Group, First Tuesdays
• 2023-08-02 | Virtual (Indianapolis, IN, US) | Indy Rust
  • Indy.rs - with Social Distancing
• 2023-08-02 | Virtual (Stuttgart, DE) | Rust Community Stuttgart
  • Rust-Meetup
• 2023-08-08 | Virtual (Dallas, TX, US) | Dallas Rust
  • Second Tuesday
• 2023-08-10 | Virtual (Nuremberg, DE) | Rust Nuremberg
  • Rust Nürnberg online
• 2023-08-15 | Virtual (Berlin, DE) | OpenTechSchool Berlin
  • Rust Hack and Learn
• 2023-08-15 | Virtual (Washington, DC, US) | Rust DC
  • Mid-month Rustful
• 2023-08-16 | Virtual (Vancouver, BC, CA) | Vancouver Rust
  • Rust Study/Hack/Hang-out
• 2023-08-22 | Virtual (Dublin, IE) | Rust Dublin
  • Rust, Serverless and AWS

Asia

• 2023-07-27 | Seoul, KR | Rust Programming Meetup Seoul
  • Seoul Rust Meetup
• 2023-07-27 | Seoul, KR | T-RUST meetup
  • 🦀 7/27(목) T-RUST Meetup 🦀 (+ 현직자 네트워킹 세션)

Europe

• 2023-07-27 | Copenhagen, DK | Copenhagen Rust Community
  • Rust metup #38 at Deloitte!
• 2023-07-27 | Vienna, AT | Rust Vienna
  • Rust Dojo
• 2023-08-17 | Reading, UK | Reading Rust Workshop
  • Reading Rust Meetup at Browns
• 2023-08-22 | Helsinki, FI | Finland Rust Meetup
  • Helsink Rustaceans First Gathering
• 2023-08-24 | Aarhus, DK | Rust Aarhus
  • Rust Aarhus Hack and Learn at Trifork

North America

• 2023-07-27 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2023-08-01 | Chicago, IL, US | Deep Dish Rust
  • Rust Happy Hour
• 2023-08-07 | Minneapolis, MN, US | Minneapolis Rust Meetup
  • Minneapolis Rust Meetup Happy Hour
• 2023-08-10 | Mountain View, CA, US | Mountain View Rust Meetup
  • Rust Meetup at Hacker Dojo
• 2023-08-10 | Lehi, UT, US | Utah Rust
  • Building a simplified JVM in Rust
• 2023-08-15 | San Francisco, CA, US | San Francisco Rust Study Group
  • Rust Hacking in Person
• 2023-08-15 | Seattle, WA, US | Seattle Rust User Group Meetup
  • Seattle Rust User Group - August Meetup
• 2023-08-17 | Nashville, TN, US | Seattle Rust User Group Meetup
  • Rust goes where it pleases. Rust on the web and embedded
• 2023-08-23 | Austin, TX, US | Rust ATX
  • Rust Lunch - Fareground

Oceania

• 2023-07-27 | Brisbane, QLD, AU | Rust Brisbane
  • July Meetup
• 2023-08-08 | Aukland, NZ | Rust AKL
  • A Peek into GPU Computing + Safer Code with Code Generation
• 2023-08-09 | Perth, WA, AU | Rust Perth
  • August 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

A rustacean is a programmer that dislikes being told "yes" in situations where they'll regret it later.

– Predrag Gruevski on mastodon

Thanks to Kevin Mehall 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