Rust 1.31.0

Language

--------

- 🎉 [This version marks the release of the 2018 edition of Rust.][54057] 🎉

- [New lifetime elision rules now allow for eliding lifetimes in functions and

impl headers.][54778] E.g. impl<'a> Reader for BufReader<'a> {} can now be

impl Reader for BufReader<'_> {}. Lifetimes are still required to be defined

in structs.

- [You can now define and use const functions.][54835] These are currently

a strict minimal subset of the [const fn RFC][RFC-911]. Refer to the

[language reference][const-reference] for what exactly is available.

- [You can now use tool lints, which allow you to scope lints from external

tools using attributes.][54870] E.g. #[allow(clippy::filter_map)].

- [#[no_mangle] and #[export_name] attributes can now be located anywhere in

a crate, not just in exported functions.][54451]

- [You can now use parentheses in pattern matches.][54497]

Compiler

--------

- [Updated musl to 1.1.20][54430]

Libraries

---------

- [You can now convert num::NonZero* types to their raw equivalents using the

From trait.][54240] E.g. u8 now implements From.

- [You can now convert a &Option into Option<&T> and &mut Option

into Option<&mut T> using the From trait.][53218]

- [You can now multiply (*) a time::Duration by a u32.][52813]

Stabilized APIs

---------------

- [slice::align_to]

- [slice::align_to_mut]

- [slice::chunks_exact]

- [slice::chunks_exact_mut]

- [slice::rchunks]

- [slice::rchunks_mut]

- [slice::rchunks_exact]

- [slice::rchunks_exact_mut]

- [Option::replace]

Cargo

-----

- [Cargo will now download crates in parallel using HTTP/2.][cargo/6005]

- [You can now rename packages in your Cargo.toml][cargo/6319] We have a guide

on [how to use the package key in your dependencies.][cargo-rename-reference]

[52813]: https://github.com/rust-lang/rust/pull/52813/

[53218]: https://github.com/rust-lang/rust/pull/53218/

[54057]: https://github.com/rust-lang/rust/pull/54057/

[54240]: https://github.com/rust-lang/rust/pull/54240/

[54430]: https://github.com/rust-lang/rust/pull/54430/

[54451]: https://github.com/rust-lang/rust/pull/54451/

[54497]: https://github.com/rust-lang/rust/pull/54497/

[54778]: https://github.com/rust-lang/rust/pull/54778/

[54835]: https://github.com/rust-lang/rust/pull/54835/

[54870]: https://github.com/rust-lang/rust/pull/54870/

[RFC-911]: https://github.com/rust-lang/rfcs/pull/911

[Option::replace]: https://doc.rust-lang.org/std/option/enum.Option.html#method.replace

[slice::align_to_mut]: https://doc.rust-lang.org/std/primitive.slice.html#method.align_to_mut

[slice::align_to]: https://doc.rust-lang.org/std/primitive.slice.html#method.align_to

[slice::chunks_exact_mut]: https://doc.rust-lang.org/std/primitive.slice.html#method.chunks_exact_mut

[slice::chunks_exact]: https://doc.rust-lang.org/std/primitive.slice.html#method.chunks_exact

[slice::rchunks_exact_mut]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_mut

[slice::rchunks_exact]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_exact

[slice::rchunks_mut]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_mut

[slice::rchunks]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks

[cargo/6005]: https://github.com/rust-lang/cargo/pull/6005/

[cargo/6319]: https://github.com/rust-lang/cargo/pull/6319/

[cargo-rename-reference]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#renaming-dependencies-in-cargotoml

[const-reference]: https://doc.rust-lang.org/reference/items/functions.html#const-functions