Rust 1.19.0

Language

--------

- [Numeric fields can now be used for creating tuple structs.][41145] [RFC 1506]

For example struct Point(u32, u32); let x = Point { 0: 7, 1: 0 };.

- [Macro recursion limit increased to 1024 from 64.][41676]

- [Added lint for detecting unused macros.][41907]

- [loop can now return a value with break.][42016] [RFC 1624]

For example: let x = loop { break 7; };

- [C compatible unions are now available.][42068] [RFC 1444] They can only

contain Copy types and cannot have a Drop implementation.

Example: union Foo { bar: u8, baz: usize }

- [Non capturing closures can now be coerced into fns,][42162] [RFC 1558]

Example: let foo: fn(u8) -> u8 = |v: u8| { v };

Compiler

--------

- [Add support for bootstrapping the Rust compiler toolchain on Android.][41370]

- [Change arm-linux-androideabi to correspond to the armeabi

official ABI.][41656] If you wish to continue targeting the armeabi-v7a ABI

you should use --target armv7-linux-androideabi.

- [Fixed ICE when removing a source file between compilation sessions.][41873]

- [Minor optimisation of string operations.][42037]

- [Compiler error message is now aborting due to previous error(s) instead of

aborting due to N previous errors][42150] This was previously inaccurate and

would only count certain kinds of errors.

- [The compiler now supports Visual Studio 2017][42225]

- [The compiler is now built against LLVM 4.0.1 by default][42948]

- [Added a lot][42264] of [new error codes][42302]

- [Added target-feature=+crt-static option][37406] [RFC 1721] Which allows

libraries with C Run-time Libraries(CRT) to be statically linked.

- [Fixed various ARM codegen bugs][42740]

Libraries

---------

- [String now implements FromIterator> and

Extend>][41449]

- [Vec now implements From<&mut [T]>][41530]

- [Box<[u8]> now implements From>][41258]

- [SplitWhitespace now implements Clone][41659]

- [[u8]::reverse is now 5x faster and [u16]::reverse is now

1.5x faster][41764]

- [eprint! and eprintln! macros added to prelude.][41192] Same as the print!

macros, but for printing to stderr.

Stabilized APIs

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

- [OsString::shrink_to_fit]

- [cmp::Reverse]

- [Command::envs]

- [thread::ThreadId]

Cargo

-----

- [Build scripts can now add environment variables to the environment

the crate is being compiled in.

Example: println!("cargo:rustc-env=FOO=bar");][cargo/3929]

- [Subcommands now replace the current process rather than spawning a new

child process][cargo/3970]

- [Workspace members can now accept glob file patterns][cargo/3979]

- [Added --all flag to the cargo bench subcommand to run benchmarks of all

the members in a given workspace.][cargo/3988]

- [Updated libssh2-sys to 0.2.6][cargo/4008]

- [Target directory path is now in the cargo metadata][cargo/4022]

- [Cargo no longer checks out a local working directory for the

crates.io index][cargo/4026] This should provide smaller file size for the

registry, and improve cloning times, especially on Windows machines.

- [Added an --exclude option for excluding certain packages when using the

--all option][cargo/4031]

- [Cargo will now automatically retry when receiving a 5xx error

from crates.io][cargo/4032]

- [The --features option now accepts multiple comma or space

delimited values.][cargo/4084]

- [Added support for custom target specific runners][cargo/3954]

Misc

----

- [Added rust-windbg.cmd][39983] for loading rust .natvis files in the

Windows Debugger.

- [Rust will now release XZ compressed packages][rust-installer/57]

- [rustup will now prefer to download rust packages with

XZ compression][rustup/1100] over GZip packages.

- [Added the ability to escape # in rust documentation][41785] By adding

additional #'s ie. ## is now #

Compatibility Notes

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

- [MutexGuard may only be Sync if T is Sync.][41624]

- [-Z flags are now no longer allowed to be used on the stable

compiler.][41751] This has been a warning for a year previous to this.

- [As a result of the -Z flag change, the cargo-check plugin no

longer works][42844]. Users should migrate to the built-in check

command, which has been available since 1.16.

- [Ending a float literal with ._ is now a hard error.

Example: 42._ .][41946]

- [Any use of a private extern crate outside of its module is now a

hard error.][36886] This was previously a warning.

- [use ::self::foo; is now a hard error.][36888] self paths are always

relative while the :: prefix makes a path absolute, but was ignored and the

path was relative regardless.

- [Floating point constants in match patterns is now a hard error][36890]

This was previously a warning.

- [Struct or enum constants that don't derive PartialEq & Eq used

match patterns is now a hard error][36891] This was previously a warning.

- [Lifetimes named '_ are no longer allowed.][36892] This was previously

a warning.

- [From the pound escape, lines consisting of multiple #s are

now visible][41785]

- [It is an error to re-export private enum variants][42460]. This is

known to break a number of crates that depend on an older version of

mustache.

- [On Windows, if VCINSTALLDIR is set incorrectly, rustc will try

to use it to find the linker, and the build will fail where it did

not previously][42607]

[36886]: https://github.com/rust-lang/rust/issues/36886

[36888]: https://github.com/rust-lang/rust/issues/36888

[36890]: https://github.com/rust-lang/rust/issues/36890

[36891]: https://github.com/rust-lang/rust/issues/36891

[36892]: https://github.com/rust-lang/rust/issues/36892

[37406]: https://github.com/rust-lang/rust/issues/37406

[39983]: https://github.com/rust-lang/rust/pull/39983

[41145]: https://github.com/rust-lang/rust/pull/41145

[41192]: https://github.com/rust-lang/rust/pull/41192

[41258]: https://github.com/rust-lang/rust/pull/41258

[41370]: https://github.com/rust-lang/rust/pull/41370

[41449]: https://github.com/rust-lang/rust/pull/41449

[41530]: https://github.com/rust-lang/rust/pull/41530

[41624]: https://github.com/rust-lang/rust/pull/41624

[41656]: https://github.com/rust-lang/rust/pull/41656

[41659]: https://github.com/rust-lang/rust/pull/41659

[41676]: https://github.com/rust-lang/rust/pull/41676

[41751]: https://github.com/rust-lang/rust/pull/41751

[41764]: https://github.com/rust-lang/rust/pull/41764

[41785]: https://github.com/rust-lang/rust/pull/41785

[41873]: https://github.com/rust-lang/rust/pull/41873

[41907]: https://github.com/rust-lang/rust/pull/41907

[41946]: https://github.com/rust-lang/rust/pull/41946

[42016]: https://github.com/rust-lang/rust/pull/42016

[42037]: https://github.com/rust-lang/rust/pull/42037

[42068]: https://github.com/rust-lang/rust/pull/42068

[42150]: https://github.com/rust-lang/rust/pull/42150

[42162]: https://github.com/rust-lang/rust/pull/42162

[42225]: https://github.com/rust-lang/rust/pull/42225

[42264]: https://github.com/rust-lang/rust/pull/42264

[42302]: https://github.com/rust-lang/rust/pull/42302

[42460]: https://github.com/rust-lang/rust/issues/42460

[42607]: https://github.com/rust-lang/rust/issues/42607

[42740]: https://github.com/rust-lang/rust/pull/42740

[42844]: https://github.com/rust-lang/rust/issues/42844

[42948]: https://github.com/rust-lang/rust/pull/42948

[RFC 1444]: https://github.com/rust-lang/rfcs/pull/1444

[RFC 1506]: https://github.com/rust-lang/rfcs/pull/1506

[RFC 1558]: https://github.com/rust-lang/rfcs/pull/1558

[RFC 1624]: https://github.com/rust-lang/rfcs/pull/1624

[RFC 1721]: https://github.com/rust-lang/rfcs/pull/1721

[Command::envs]: https://doc.rust-lang.org/std/process/struct.Command.html#method.envs

[OsString::shrink_to_fit]: https://doc.rust-lang.org/std/ffi/struct.OsString.html#method.shrink_to_fit

[cmp::Reverse]: https://doc.rust-lang.org/std/cmp/struct.Reverse.html

[thread::ThreadId]: https://doc.rust-lang.org/std/thread/struct.ThreadId.html

[cargo/3929]: https://github.com/rust-lang/cargo/pull/3929

[cargo/3954]: https://github.com/rust-lang/cargo/pull/3954

[cargo/3970]: https://github.com/rust-lang/cargo/pull/3970

[cargo/3979]: https://github.com/rust-lang/cargo/pull/3979

[cargo/3988]: https://github.com/rust-lang/cargo/pull/3988

[cargo/4008]: https://github.com/rust-lang/cargo/pull/4008

[cargo/4022]: https://github.com/rust-lang/cargo/pull/4022

[cargo/4026]: https://github.com/rust-lang/cargo/pull/4026

[cargo/4031]: https://github.com/rust-lang/cargo/pull/4031

[cargo/4032]: https://github.com/rust-lang/cargo/pull/4032

[cargo/4084]: https://github.com/rust-lang/cargo/pull/4084

[rust-installer/57]: https://github.com/rust-lang/rust-installer/pull/57

[rustup/1100]: https://github.com/rust-lang-nursery/rustup.rs/pull/1100