Announcing Rust 1.14

The Rust team is happy to announce the latest version of Rust, 1.14.0. Rust is a systems programming language focused on safety, speed, and concurrency.

As always, you can install Rust 1.14.0 from the appropriate page on our website, and check out the detailed release notes for 1.14.0 on GitHub. 1230 patches were landed in this release.

What's in 1.14.0 stable

One of the biggest features in Rust 1.14 isn't actually in the language or compiler: the rustup tool has reached a 1.0 release, and is now the recommended way to install Rust from the project directly. Rustup does a bit more than just install Rust:

rustup installs The Rust Programming Language from the official release channels, enabling you to easily switch between stable, beta, and nightly compilers and keep them updated. It makes cross-compiling simpler with binary builds of the standard library for common platforms. And it runs on all platforms Rust supports, including Windows.

We had a previous post about Rustup back in May. You can learn more about it there, or by checking it out on GitHub.

Another exciting feature is experimental support for WebAssembly as a target, wasm32-unknown-emscripten. It is still early days, and there's a lot of bugs to shake out, so please give it a try and report them! To give you a small taste of how it works, once you have emscripten installed, compiling some Rust code to WebAssembly is as easy as:

rustup target add wasm32-unknown-emscripten
$ echo 'fn main() { println!("Hello, Emscripten!"); }' > hello.rs
$ rustc --target=wasm32-unknown-emscripten hello.rs
$ node hello.js

The community has been doing interesting, experimental work in this area: see Jan-Erik's slides for the workshop he ran at Rust Belt Rust for some examples, or check out Tim's example of the classic TodoMVC project. This implementation builds off of his webplatform crate, which exposes the DOM to Rust.

Speaking of platforms, a large number of platforms have gained additional support:

For rustc:

mips-unknown-linux-gnu
mipsel-unknown-linux-gnu
mips64-unknown-linux-gnuabi64
mips64el-unknown-linux-gnuabi64
powerpc-unknown-linux-gnu
powerpc64-unknown-linux-gnu
powerpc64le-unknown-linux-gnu
s390x-unknown-linux-gnu

And for std:

arm-unknown-linux-musleabi
arm-unknown-linux-musleabihf
armv7-unknown-linux-musleabihf

If you're using one of these platforms, follow the instructions on the website to install, or add the targets to an existing installation with rustup target add.

These platforms are all 'tier 2', please see our page on platform support for more details.

Just like how the community is doing interesting work on the WebAssembly target, there's also neat things going on with increasing Rust's target support beyond what's listed above. xargo allows for easy cross-compilation of Rust to bare-metal targets. If you're writing an operating system in Rust, or doing something interesting on a microcontroller, xargo can make your life a lot simpler.

The landing of MIR over the last few releases means that a number of improvements to compile times have landed, with more coming in the future.

In the language, one small improvement has landed: support for RFC 1492. This small addition lets you use .. in more places. Previously, say you had a struct like this:

struct Point {
    x: i32,
    y: i32,
    z: i32,
}

In any context where you're doing a pattern match, you could use .. to ignore the parts you don't care about. For example:

let p = Point { x: 0, y: 1, z: 2 };

match p {
    Point { x, .. } => println!("x is {}", x),
}

The .. ignores y and z.

Consider a similar Point, but as a tuple struct:

struct Point(i32, i32, i32);

Previously, you could use .. to ignore all three elements:

let p = Point(0, 1, 2);

match p {
    Point(..) => println!("found a point"),
}

But you could not use it to only ignore parts of the tuple:

let p = Point(0, 1, 2);

match p {
    Point(x, ..) => println!("x is {}", x),
}

This was an inconsistency, and so with RFC 1492 stabilized, compiles fine as of this release. This applies to more situations than tuples; please see the RFC for more details.

Library stabilizations

There have been a number of additions to the standard library, but they don't fit into particularly nice categories for this release. Here's the highlights:

println!(), with no arguments, prints newline. Previously, an empty string was required to achieve the same.
Wrapping impls standard binary and unary operators on references, as well as the Sum and Product iterators, making references to these types easier to use.
Implement From<Cow<str>> for String and From<Cow<[T]>> for Vec<T>. These implementations make sense, but were not yet added.
Expand .zip() specialization to .map() and .cloned() for improved performance.
Implement RefUnwindSafe for atomic types, as these types are "unwind safe," though that wasn't obvious at first.
Specialize Vec::extend to Vec::extend_from_slice for performance gains.
Don't reuse HashMap random seeds. This helps to mitigate one type of DDoS attack.
The internal memory layout of HashMap is more cache-friendly, for significant improvements in some operations
Impl Add<{str, Cow<str>}> for Cow<str>. We already support Add for other string types, so not having it on Cow is inconsistent.

See the detailed release notes for more.

Cargo features

As for Cargo, RFC 1721 has been implemented. Cargo will now pass along the values printed by rustc --print cfg to build scripts. The motivation for this feature is that Cargo can now compile objects for statically linking against the msvcrt on the MSVC platform.

Cargo now works properly with a read-only CARGO_HOME.

Finally, Cargo will ignore the panic configuration for the test and bench profiles. This is important because the test runner relies on panics counting as failing tests, and so with panic=abort, a failing test would abort the entire test suite.

See the detailed release notes for more.

Contributors to 1.14.0

We had 144 individuals contribute to 1.14.0. Thank you so much!

Abhishek Chanda
Adam Perry
Ahmed Charles
Aidan Hobson Sayers
Aleksey Kladov
Alexander von Gluck IV
Alex Burka
Alex Crichton
Alex von Gluck IV
Amanieu d'Antras
Andrea Corradi
Andrea Pretto
Andreas Sommer
Andre Bogus
Andrew Paseltiner
angelsl
Anthony Ramine
Ariel Ben-Yehuda
arthurprs
Austin Hicks
bors
Brian Anderson
Bunts Thy Unholy
CensoredUsername
Chris McDonald
Christopher
christopherdumas
Christopher Serr
Cobrand
Corey Farwell
Cristi Cobzarenco
Daan Sprenkels
Danny Hua
David Henningsson
Devon Hollowood
Dmitry Gritsay
Dominik Inführ
Duncan
Eduard Burtescu
Eduard-Mihai Burtescu
Eric Roshan-Eisner
est31
Fabian Frei
Federico Mena Quintero
Felix S. Klock II
Florian Diebold
Florian Hartwig
Florian Zeitz
Frank Rehberger
Gavin Baker
Geoffry Song
Guillaume Gomez
iirelu
James Miller
Jan-Erik Rediger
Jared Roesch
Jeffrey Seyfried
Jesus Garlea
Jethro Beekman
Joe Neeman
Johannes Muenzel
John Firebaugh
John Hodge
johnthagen
Jonas Schievink
Jonathan Turner
Jorge Aparicio
Josh Stone
Josh Triplett
Keegan McAllister
Keith Yeung
KillTheMule
Konrad Borowski
leonardo.yvens
Liigo Zhuang
loggerhead
Manish Goregaokar
Marcin Fatyga
Mark-Simulacrum
Martin Glagla
Martin Thoresen
Mathieu Borderé
Mathieu Poumeyrol
Matt Brubeck
Matthew Piziak
Matwey V. Kornilov
mcarton
Michael Woerister
Mikhail Modin
Mikko Rantanen
msiglreith
Nabeel Omer
Nathan Musoke
Nicholas Nethercote
Nick Cameron
Nick Fitzgerald
Nick Stevens
Nikhil Shagrithaya
Niko Matsakis
Oliver Middleton
p512
ParkHanbum
Paul Lange
Paulo Matos
Paul Osborne
Peter Atashian
Peter N
Philip Davis
Pieter Frenssen
Pweaver (Paul Weaver)
pweyck
QuietMisdreavus
Raph Levien
Razican
Robin Stocker
Ross Schulman
Ryan Senior
Scott Olson
Seo Sanghyeon
Simonas Kazlauskas
Simon Sapin
Srinivas Reddy Thatiparthy
Stefan Schindler
Stephen M. Coakley
Steve Klabnik
Steven Fackler
Tamir Duberstein
Taylor Cramer
Tim Neumann
Tobias Bucher
Tomasz Miąsko
tormol
Tshepang Lekhonkhobe
Ulrik Sverdrup
Vadim Chugunov
Vadim Petrochenkov
Vadzim Dambrouski
Vangelis Katsikaros
Wang Xuerui
Wesley Wiser
Zack M. Davis
Zoffix Znet
Артём Павлов [Artyom Pavlov]
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