Rust 1.8.0

Language

--------

* Rust supports overloading of compound assignment statements like

+= by implementing the [AddAssign], [SubAssign],

[MulAssign], [DivAssign], [RemAssign], [BitAndAssign],

[BitOrAssign], [BitXorAssign], [ShlAssign], or [ShrAssign]

traits. [RFC 953].

* Empty structs can be defined with braces, as in struct Foo { }, in

addition to the non-braced form, struct Foo;. [RFC 218].

Libraries

---------

* Stabilized APIs:

* [str::encode_utf16] (renamed from utf16_units)

* [str::EncodeUtf16] (renamed from Utf16Units)

* [Ref::map]

* [RefMut::map]

* [ptr::drop_in_place]

* [time::Instant]

* [time::SystemTime]

* [Instant::now]

* [Instant::duration_since] (renamed from duration_from_earlier)

* [Instant::elapsed]

* [SystemTime::now]

* [SystemTime::duration_since] (renamed from duration_from_earlier)

* [SystemTime::elapsed]

* Various Add/Sub impls for Time and SystemTime

* [SystemTimeError]

* [SystemTimeError::duration]

* Various impls for SystemTimeError

* [UNIX_EPOCH]

* [AddAssign], [SubAssign], [MulAssign], [DivAssign],

[RemAssign], [BitAndAssign], [BitOrAssign],

[BitXorAssign], [ShlAssign], [ShrAssign].

* [The write! and writeln! macros correctly emit errors if any of

their arguments can't be formatted][1.8w].

* [Various I/O functions support large files on 32-bit Linux][1.8l].

* [The Unix-specific raw modules, which contain a number of

redefined C types are deprecated][1.8r], including os::raw::unix,

os::raw::macos, and os::raw::linux. These modules defined types

such as ino_t and dev_t. The inconsistency of these definitions

across platforms was making it difficult to implement std

correctly. Those that need these definitions should use the libc

crate. [RFC 1415].

* The Unix-specific MetadataExt traits, including

os::unix::fs::MetadataExt, which expose values such as inode

numbers [no longer return platform-specific types][1.8r], but

instead return widened integers. [RFC 1415].

* [btree_set::{IntoIter, Iter, Range} are covariant][1.8cv].

* [Atomic loads and stores are not volatile][1.8a].

* [All types in sync::mpsc implement fmt::Debug][1.8mp].

Performance

-----------

* [Inlining hash functions lead to a 3% compile-time improvement in

some workloads][1.8h].

* When using jemalloc, its symbols are [unprefixed so that it

overrides the libc malloc implementation][1.8h]. This means that for

rustc, LLVM is now using jemalloc, which results in a 6%

compile-time improvement on a specific workload.

* [Avoid quadratic growth in function size due to cleanups][1.8cu].

Misc

----

* [32-bit MSVC builds finally implement unwinding][1.8ms].

i686-pc-windows-msvc is now considered a tier-1 platform.

* [The --print targets flag prints a list of supported targets][1.8t].

* [The --print cfg flag prints the cfgs defined for the current

target][1.8cf].

* [rustc can be built with an new Cargo-based build system, written

in Rust][1.8b]. It will eventually replace Rust's Makefile-based

build system. To enable it configure with configure --rustbuild.

* [Errors for non-exhaustive match patterns now list up to 3 missing

variants while also indicating the total number of missing variants

if more than 3][1.8m].

* [Executable stacks are disabled on Linux and BSD][1.8nx].

* The Rust Project now publishes binary releases of the standard

library for a number of tier-2 targets:

armv7-unknown-linux-gnueabihf, powerpc-unknown-linux-gnu, powerpc64-unknown-linux-gnu, powerpc64le-unknown-linux-gnu x86_64-rumprun-netbsd. These can be installed with

tools such as [multirust][1.8mr].

Cargo

-----

* [cargo init creates a new Cargo project in the current

directory][1.8ci]. It is otherwise like cargo new.

* [Cargo has configuration keys for -v and

--color][1.8cc]. verbose and color, respectively, go in the [term] section of .cargo/config.

* [Configuration keys that evaluate to strings or integers can be set

via environment variables][1.8ce]. For example the build.jobs key

can be set via CARGO_BUILD_JOBS. Environment variables take

precedence over config files.

* [Target-specific dependencies support Rust cfg syntax for

describing targets][1.8cfg] so that dependencies for multiple

targets can be specified together. [RFC 1361].

* [The environment variables CARGO_TARGET_ROOT, RUSTC, and

RUSTDOC take precedence over the build.target-dir, build.rustc, and build.rustdoc configuration values][1.8cfv].

* [The child process tree is killed on Windows when Cargo is

killed][1.8ck].

* [The build.target configuration value sets the target platform,

like --target][1.8ct].

Compatibility Notes

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

* [Unstable compiler flags have been further restricted][1.8u]. Since

1.0 -Z flags have been considered unstable, and other flags that

were considered unstable additionally required passing -Z

unstable-options to access. Unlike unstable language and library

features though, these options have been accessible on the stable

release channel. Going forward, *new unstable flags will not be

available on the stable release channel*, and old unstable flags

will warn about their usage. In the future, all unstable flags will

be unavailable on the stable release channel.

* [It is no longer possible to match on empty enum variants using

the Variant(..) syntax][1.8v]. This has been a warning since 1.6.

* The Unix-specific MetadataExt traits, including

os::unix::fs::MetadataExt, which expose values such as inode

numbers [no longer return platform-specific types][1.8r], but

instead return widened integers. [RFC 1415].

* [Modules sourced from the filesystem cannot appear within arbitrary

blocks, but only within other modules][1.8mf].

* [--cfg compiler flags are parsed strictly as identifiers][1.8c].

* On Unix, [stack overflow triggers a runtime abort instead of a

SIGSEGV][1.8so].

* [Command::spawn and its equivalents return an error if any of

its command-line arguments contain interior NULs][1.8n].

* [Tuple and unit enum variants from other crates are in the type

namespace][1.8tn].

* [On Windows rustc emits .lib files for the staticlib library

type instead of .a files][1.8st]. Additionally, for the MSVC

toolchain, rustc emits import libraries named foo.dll.lib

instead of foo.lib.

[1.8a]: https://github.com/rust-lang/rust/pull/30962

[1.8b]: https://github.com/rust-lang/rust/pull/31123

[1.8c]: https://github.com/rust-lang/rust/pull/31530

[1.8cc]: https://github.com/rust-lang/cargo/pull/2397

[1.8ce]: https://github.com/rust-lang/cargo/pull/2398

[1.8cf]: https://github.com/rust-lang/rust/pull/31278

[1.8cfg]: https://github.com/rust-lang/cargo/pull/2328

[1.8ci]: https://github.com/rust-lang/cargo/pull/2081

[1.8ck]: https://github.com/rust-lang/cargo/pull/2370

[1.8ct]: https://github.com/rust-lang/cargo/pull/2335

[1.8cu]: https://github.com/rust-lang/rust/pull/31390

[1.8cfv]: https://github.com/rust-lang/cargo/issues/2365

[1.8cv]: https://github.com/rust-lang/rust/pull/30998

[1.8h]: https://github.com/rust-lang/rust/pull/31460

[1.8l]: https://github.com/rust-lang/rust/pull/31668

[1.8m]: https://github.com/rust-lang/rust/pull/31020

[1.8mf]: https://github.com/rust-lang/rust/pull/31534

[1.8mp]: https://github.com/rust-lang/rust/pull/30894

[1.8mr]: https://users.rust-lang.org/t/multirust-0-8-with-cross-std-installation/4901

[1.8ms]: https://github.com/rust-lang/rust/pull/30448

[1.8n]: https://github.com/rust-lang/rust/pull/31056

[1.8nx]: https://github.com/rust-lang/rust/pull/30859

[1.8r]: https://github.com/rust-lang/rust/pull/31551

[1.8so]: https://github.com/rust-lang/rust/pull/31333

[1.8st]: https://github.com/rust-lang/rust/pull/29520

[1.8t]: https://github.com/rust-lang/rust/pull/31358

[1.8tn]: https://github.com/rust-lang/rust/pull/30882

[1.8u]: https://github.com/rust-lang/rust/pull/31793

[1.8v]: https://github.com/rust-lang/rust/pull/31757

[1.8w]: https://github.com/rust-lang/rust/pull/31904

[RFC 1361]: https://github.com/rust-lang/rfcs/blob/master/text/1361-cargo-cfg-dependencies.md

[RFC 1415]: https://github.com/rust-lang/rfcs/blob/master/text/1415-trim-std-os.md

[RFC 218]: https://github.com/rust-lang/rfcs/blob/master/text/0218-empty-struct-with-braces.md

[RFC 953]: https://github.com/rust-lang/rfcs/blob/master/text/0953-op-assign.md

[AddAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.AddAssign.html

[BitAndAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.BitAndAssign.html

[BitOrAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.BitOrAssign.html

[BitXorAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.BitXorAssign.html

[DivAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.DivAssign.html

[Instant::duration_since]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html#method.duration_since

[Instant::elapsed]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html#method.elapsed

[Instant::now]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html#method.now

[MulAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.MulAssign.html

[Ref::map]: http://doc.rust-lang.org/nightly/std/cell/struct.Ref.html#method.map

[RefMut::map]: http://doc.rust-lang.org/nightly/std/cell/struct.RefMut.html#method.map

[RemAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.RemAssign.html

[ShlAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.ShlAssign.html

[ShrAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.ShrAssign.html

[SubAssign]: http://doc.rust-lang.org/nightly/std/ops/trait.SubAssign.html

[SystemTime::duration_since]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html#method.duration_since

[SystemTime::elapsed]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html#method.elapsed

[SystemTime::now]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html#method.now

[SystemTimeError::duration]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTimeError.html#method.duration

[SystemTimeError]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTimeError.html

[UNIX_EPOCH]: http://doc.rust-lang.org/nightly/std/time/constant.UNIX_EPOCH.html

[ptr::drop_in_place]: http://doc.rust-lang.org/nightly/std/ptr/fn.drop_in_place.html

[str::EncodeUtf16]: http://doc.rust-lang.org/nightly/std/str/struct.EncodeUtf16.html

[str::encode_utf16]: http://doc.rust-lang.org/nightly/std/primitive.str.html#method.encode_utf16

[time::Instant]: http://doc.rust-lang.org/nightly/std/time/struct.Instant.html

[time::SystemTime]: http://doc.rust-lang.org/nightly/std/time/struct.SystemTime.html