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

• Making WebAssembly better for Rust & for all languages.
• Building a fast Electron app with Rust.
• Statuses of unstable standard library features.
• Building a DNS server in Rust.
• Type-directed metaprogramming in Rust.
• Multicasting in Rust.
• Mutating Rust: Pattern boldness and deciding if two types are equal.
• kernel-roulette: An example Linux kernel module written in Rust.
• CLI Working Group newsletter 1.
• The Embedded Working Group newsletter 1.
• This week in Rust docs 97.
• [podcast] Rusty Spike Podcast - episode 23. Ember, the roadmap, Redmonk, IDEs, and MIRI.

Crate of the Week

This week's crate is noisy_float, a crate with surprisingly useful floating point types that would rather panic than be Not a Number. Thanks to Ayose Cazorla 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.

• rustc-guide is more of a writing project than a programming project, but there are a bunch of things that need doing. There are some easier issues, issues which might require a bit of investigation/code reading, and issues which probably require some advanced knowledge or a lot of time.
• Get started with these beginner-friendly issues.

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

Updates from Rust Core

145 pull requests were merged in the last week

• coherence diagnostic tweaks
• two phase borrows rewrite
• minimum viable chalkification (hooray!)
• make CodeMap and FileMap thread-safe
• introduce canonical queries, use for normalization and dropck-outlives
• remove auto trait implementation section when empty
• enable embedding LLVM bitcode for iOS
• delegate debug implementation for InternedString
• check stability of macro invocations
• make assert a built-in procedural macro
• fix hygene issue when deriving Debug
• add info message for -Wall command (welcome, C users)
• move ascii::escape_default to libcore
• fallible allocation (RFC #2116)
• add intrinsics for portable packed SIMD vector reductions
• stabilize inclusive range (..=) (RFC #1192)
• stabilize ! (RFC #1216)
• remove or hide deprecated unstable SipHasher{13, 24}
• cargo: faster resolver: clean code and the backtrack_stack, also cache conflicting_activations
• rustbuild: faster submodule updating

New Contributors

• Alan Du
• Alexandre Martin
• Alex Butler
• Boris-Chengbiao Zhou
• Dileep Bapat
• dragan.mladjenovic
• Eric Huss
• snf
• Yukio Siraichi

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 2349: Standard library API for immovable types.
• RFC 2307: Add std::num::NonZeroU32 and friends, deprecate core::nonzero.
• RFC 2169: Add Euclidean modulo & division functionality for integers.
• RFC 2203: Constants in array repeat expressions.
• RFC 2342: Allow if and match in constants.

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. This week's FCPs are:

• [disposition: merge] Self in type definitions allowing enum List<T> { Nil, Cons(T, Box<Self>) }.
• [disposition: postpone] Implement parent items with child traits.
• [disposition: close] Make the as keyword consider Into Trait implementations.
• [disposition: close] Quick dbg!(expr) macro.

New RFCs

• Custom self types.
• Allow arbitrary enums to have explicit discriminants.
• Formalise reborrows.

Upcoming Events

The community team is trying to improve outreach to meetup organisers. Please fill out their call for contact info if you are running or used to run a meetup.

• Mar 22. Rust release triage.
• Mar 25. Mountain View, US - Open Table / Icebreaker: what projects are you working on.
• Mar 27. Berlin, DE - Hack and Learn with the Rust team.
• Mar 27. Berlin, DE - OpenTechSchool Berlin - Rust Hack and Learn.
• Mar 27. Rust Community Content Subteam Meeting at #rust-content on irc.mozilla.org.
• Mar 27. Kitchener, CA - An Introduction To Rust & Writing a Crate (Kahan Sums).
• Mar 28. Milano, IT - Let's play with Procedural Macros in Rust.
• Mar 28. Rust Community Team Meeting at #rust-community on irc.mozilla.org.
• Mar 28. Rust Events Team Meeting.
• Mar 29. Helsinki, FI - March Rust meetup.
• Apr 1. Mountain View, US - Open Table / Icebreaker: what projects are you working on.
• Apr 3. Johannesburg, ZA - Monthly Meetup of the Johannesburg Rustaceans.
• Apr 4. Vancouver, CA - Rust Study/Hack/Hang-out night.
• Apr 4. Atlanta, US - Grab a beer with fellow Rustaceans.
• Apr 4. Indianapolis, US - Indy.rs.
• Apr 4. Berlin, DE - OpenTechSchool Berlin - Rust Hack and Learn.
• Apr 4. Rust Community Team Meeting at #rust-community on irc.mozilla.org.
• Apr 5. Rust release triage.

If you are running a Rust event please add it to the calendar to get it mentioned here. Email the Rust Community Team for access.

Rust Jobs

No jobs listed for this week.

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

Quote of the Week

Imagine going back in time and telling the reporter “this bug will get fixed 16 years from now, and the code will be written in a systems programming language that doesn’t exist yet”.

— Nicholas Nethercote.

Thanks to jleedev!

Submit your quotes for next week!

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