Hello and welcome to another issue of This Week in Rust! Rust is a systems language pursuing the trifecta: safety, concurrency, and speed. This is a weekly summary of its progress and community. Want something mentioned? Tweet us at @ThisWeekInRust or send us a pull request. Want to get involved? We love contributions.

This Week in Rust is openly developed on GitHub. If you find any errors in this week's issue, please submit a PR.

Updates from Rust Community

News & Blog Posts

• LLVM: closing the gap - cross-language LTO between Rust and C/C++.
• Weld: accelerating numpy, scikit and pandas as much as 100x with Rust and LLVM.
• Declarative memory management.
• Generic newtypes: A way to work around the orphan rule.
• Async builders.
• Adventures in motion control: top-level infrastructure.
• Build an NB-IoT GPS Tracker on STM32 L476 with Apache Mynewt and Embedded Rust.
• Navigating the Rust OSS community.

Crate of the Week

This week's crate is mun_runtime, an experimental hot-reloading oriented runtime in Rust.

Thanks to Vikrant for the suggestion!

Submit your suggestions and votes for next week!

Call for Participation

Always wanted to contribute to open-source projects but didn't 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 issues were proposed for CfP.

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

Updates from Rust Core

278 pull requests were merged in the last week

• Infer consts more consistently
• Parse assoc type bounds in generic params and provide custom diagnostic
• Update to LLVM 9.0.0
• rustbuild: Copy crate doc files fewer times
• Point at original span when emitting unreachable lint
• record fewer adjustment types in generator witnesses, avoid spurious drops in MIR construction
• More ObligationForest improvements
• Replace state_for_location with DataflowResultsCursor
• Load proc macro metadata in the correct order
• Various ObligationForest improvements
• Shrink SubregionOrigin
• save-analysis: Nest typeck tables when processing functions/methods
• Add cmp::{min_by, min_by_key, max_by, max_by_key}
• Stabilize param_attrs in Rust 1.39.0
• Make sure interned constants are immutable
• Added ability to crosscompile doctests
• Add std_detect::detect::features() API that returns iterator of target-features and reject unstable features in feature-detection macros

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

• [disposition: postpone] Existential types with external definition.
• [disposition: postpone] Custom self types.
• [disposition: postpone] Cargo versioning.
• [disposition: close] Project-based Examples for Cargo Projects.

Tracking Issues & PRs

• [disposition: merge] Stabilize macros in some more positions.
• [disposition: merge] Stabilize Option::as_deref and Option::as_deref_mut.
• [disposition: merge] Stabilize mem::take (mem_take).
• [disposition: merge] Tracking issue for RFC 2008: Future-proofing enums/structs with #[non_exhaustive] attribute.
• [disposition: merge] Support repr(simd) on ADTs containing a single array field.
• [disposition: merge] syntax: Support modern attribute syntax in the meta matcher.
• [disposition: merge] convert \r\n -> \n in include_str! macro.
• [disposition: close] Regression: : cannot determine resolution for the attribute macro test.
• [disposition: close] Expose Linux syscall interface.

New RFCs

No new RFCs were proposed this week.

Upcoming Events

Africa

• Oct 2. Johannesburg, ZA - Johannesburg Rust Meetup - futures (part 2).

Asia Pacific

• Sep 28. Taipei, TW - Rust Taiwan Meetup.
• Oct 7. Auckland, NZ - Rust AKL - Introduction to Rust (session 2 of 3).

Europe

• Sep 26. Turin, IT - Mozilla Torino - Gruppo di studio Rust.
• Sep 26. London, GB - Rust London User Group - Hack 'n Learn September 2019.
• Oct 1. Göteborg, SE - Rust Gbg — Golden October Rust 2019.
• Oct 2. Berlin, DE - OpenTechSchool Berlin - Rust Hack and Learn.
• Oct 2. Cologne, DE - Rust Cologne - Open Space.
• Oct 3. Toulouse, FR - Rust talks at DevFest Toulouse 2019.
• Oct 4. Toulouse, FR - Toulouse Rust Meetup - Future
  .
• Oct 4. Darmstadt, DE - Hacktoberfest for Rustaceans.
• Oct 5. Kharkiv, UA - PeerLab Kharkiv #Rust: AsyncIO.
• Oct 10. Helsinki, FI - Finland Rust-lang Group - October meetup.
• Oct 10. Warsaw, PL - Rust Warsaw - reboot.

North America

• Sep 26. New York, NY - Local Native: A Decentralized Cross-platform App Developed with Rust.
• Oct 1. Toronto, ON, CA - Rust Toronto - Rust for the Web.
• Oct 2. Indianapolis, IN, US - Indy.rs.
• Oct 2. Vancouver, BC, CA - Vancouver Rust meetup.
• Oct 2. Boston, MA, US - Boston Rust Meetup at VMware.
• Oct 5. Cleveland, OH, US - Cleveland RustBridge.
• Oct 8. Detroit, MI, US - Detroit Rust - Diving into Rust web frameworks.
• Oct 9. Atlanta, GA, US - Grab a beer with fellow Rustaceans.
• Oct 10. Columbus, OH, US - Columbus Rust Society - Monthly Meeting.

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.

Rust Jobs

• 2D Graphics Programmer at Dungeonfog, Vienna, AT (Remote available).
• Principal Software Engineer at Microsoft, Redmond, WA, US.
• Multiple Rust positions at Parity, Berlin, DE (Remote available).
• Software Engineer at 3DSignals, Kfar Saba, IL.
• Senior Engineer at Ditto at San Francisco, US (Remote available).

Tweet us at @ThisWeekInRust to get your job offers listed here!

Quote of the Week

I don’t like Rust being pigeon holed as a “safer C++”—it’s so much more than that.

It’s been stated more often lately. It overlooks the fact that Rust has actively opened the door to systems programming to people coming from langs like Javascript, where C and C++ never did.

– Benjamin Fry on twitter

Thanks to Sverre Johann Bjørke for the suggestion!

Please submit quotes and vote for next week!

This Week in Rust is edited by: nasa42, llogiq, and Flavsditz.

Discuss on r/rust.