Rust 1.6.0

Language

--------

* The #![no_std] attribute causes a crate to not be linked to the

standard library, but only the [core library][1.6co], as described

in [RFC 1184]. The core library defines common types and traits but

has no platform dependencies whatsoever, and is the basis for Rust

software in environments that cannot support a full port of the

standard library, such as operating systems. Most of the core

library is now stable.

Libraries

---------

* Stabilized APIs:

[Read::read_exact],

[ErrorKind::UnexpectedEof] (renamed from UnexpectedEOF),

[fs::DirBuilder], [fs::DirBuilder::new],

[fs::DirBuilder::recursive], [fs::DirBuilder::create],

[os::unix::fs::DirBuilderExt],

[os::unix::fs::DirBuilderExt::mode], [vec::Drain],

[vec::Vec::drain], [string::Drain], [string::String::drain],

[vec_deque::Drain], [vec_deque::VecDeque::drain],

[collections::hash_map::Drain],

[collections::hash_map::HashMap::drain],

[collections::hash_set::Drain],

[collections::hash_set::HashSet::drain],

[collections::binary_heap::Drain],

[collections::binary_heap::BinaryHeap::drain],

[Vec::extend_from_slice] (renamed from push_all),

[Mutex::get_mut], [Mutex::into_inner], [RwLock::get_mut],

[RwLock::into_inner],

[Iterator::min_by_key] (renamed from min_by),

[Iterator::max_by_key] (renamed from max_by).

* The [core library][1.6co] is stable, as are most of its APIs.

* [The assert_eq! macro supports arguments that don't implement

Sized][1.6ae], such as arrays. In this way it behaves more like assert!.

* Several timer functions that take duration in milliseconds [are

deprecated in favor of those that take Duration][1.6ms]. These

include Condvar::wait_timeout_ms, thread::sleep_ms, and

thread::park_timeout_ms.

* The algorithm by which Vec reserves additional elements was

[tweaked to not allocate excessive space][1.6a] while still growing

exponentially.

* From conversions are [implemented from integers to floats][1.6f]

in cases where the conversion is lossless. Thus they are not

implemented for 32-bit ints to f32, nor for 64-bit ints to f32

or f64. They are also not implemented for isize and usize

because the implementations would be platform-specific. From is

also implemented from f32 to f64.

* From<&Path> and From are implemented for Cow.

* From is implemented for Box, Rc and Arc.

* IntoIterator is implemented for &PathBuf and &Path.

* [BinaryHeap was refactored][1.6bh] for modest performance

improvements.

* Sorting slices that are already sorted [is 50% faster in some

cases][1.6s].

Cargo

-----

* Cargo will look in $CARGO_HOME/bin for subcommands [by default][1.6c].

* Cargo build scripts can specify their dependencies by emitting the

[rerun-if-changed][1.6rr] key.

* crates.io will reject publication of crates with dependencies that

have a wildcard version constraint. Crates with wildcard

dependencies were seen to cause a variety of problems, as described

in [RFC 1241]. Since 1.5 publication of such crates has emitted a

warning.

* cargo clean [accepts a --release flag][1.6cc] to clean the

release folder. A variety of artifacts that Cargo failed to clean

are now correctly deleted.

Misc

----

* The unreachable_code lint [warns when a function call's argument

diverges][1.6dv].

* The parser indicates [failures that may be caused by

confusingly-similar Unicode characters][1.6uc]

* Certain macro errors [are reported at definition time][1.6m], not

expansion.

Compatibility Notes

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

* The compiler no longer makes use of the [RUST_PATH][1.6rp]

environment variable when locating crates. This was a pre-cargo

feature for integrating with the package manager that was

accidentally never removed.

* [A number of bugs were fixed in the privacy checker][1.6p] that

could cause previously-accepted code to break.

* [Modules and unit/tuple structs may not share the same name][1.6ts].

* [Bugs in pattern matching unit structs were fixed][1.6us]. The tuple

struct pattern syntax (Foo(..)) can no longer be used to match

unit structs. This is a warning now, but will become an error in

future releases. Patterns that share the same name as a const are

now an error.

* A bug was fixed that causes [rustc not to apply default type

parameters][1.6xc] when resolving certain method implementations of

traits defined in other crates.

[1.6a]: https://github.com/rust-lang/rust/pull/29454

[1.6ae]: https://github.com/rust-lang/rust/pull/29770

[1.6bh]: https://github.com/rust-lang/rust/pull/29811

[1.6c]: https://github.com/rust-lang/cargo/pull/2192

[1.6cc]: https://github.com/rust-lang/cargo/pull/2131

[1.6co]: http://doc.rust-lang.org/core/index.html

[1.6dv]: https://github.com/rust-lang/rust/pull/30000

[1.6f]: https://github.com/rust-lang/rust/pull/29129

[1.6m]: https://github.com/rust-lang/rust/pull/29828

[1.6ms]: https://github.com/rust-lang/rust/pull/29604

[1.6p]: https://github.com/rust-lang/rust/pull/29726

[1.6rp]: https://github.com/rust-lang/rust/pull/30034

[1.6rr]: https://github.com/rust-lang/cargo/pull/2134

[1.6s]: https://github.com/rust-lang/rust/pull/29675

[1.6ts]: https://github.com/rust-lang/rust/issues/21546

[1.6uc]: https://github.com/rust-lang/rust/pull/29837

[1.6us]: https://github.com/rust-lang/rust/pull/29383

[1.6xc]: https://github.com/rust-lang/rust/issues/30123

[RFC 1184]: https://github.com/rust-lang/rfcs/blob/master/text/1184-stabilize-no_std.md

[RFC 1241]: https://github.com/rust-lang/rfcs/blob/master/text/1241-no-wildcard-deps.md

[ErrorKind::UnexpectedEof]: http://doc.rust-lang.org/nightly/std/io/enum.ErrorKind.html#variant.UnexpectedEof

[Iterator::max_by_key]: http://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.max_by_key

[Iterator::min_by_key]: http://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.min_by_key

[Mutex::get_mut]: http://doc.rust-lang.org/nightly/std/sync/struct.Mutex.html#method.get_mut

[Mutex::into_inner]: http://doc.rust-lang.org/nightly/std/sync/struct.Mutex.html#method.into_inner

[Read::read_exact]: http://doc.rust-lang.org/nightly/std/io/trait.Read.html#method.read_exact

[RwLock::get_mut]: http://doc.rust-lang.org/nightly/std/sync/struct.RwLock.html#method.get_mut

[RwLock::into_inner]: http://doc.rust-lang.org/nightly/std/sync/struct.RwLock.html#method.into_inner

[Vec::extend_from_slice]: http://doc.rust-lang.org/nightly/collections/vec/struct.Vec.html#method.extend_from_slice

[collections::binary_heap::BinaryHeap::drain]: http://doc.rust-lang.org/nightly/std/collections/binary_heap/struct.BinaryHeap.html#method.drain

[collections::binary_heap::Drain]: http://doc.rust-lang.org/nightly/std/collections/binary_heap/struct.Drain.html

[collections::hash_map::Drain]: http://doc.rust-lang.org/nightly/std/collections/hash_map/struct.Drain.html

[collections::hash_map::HashMap::drain]: http://doc.rust-lang.org/nightly/std/collections/hash_map/struct.HashMap.html#method.drain

[collections::hash_set::Drain]: http://doc.rust-lang.org/nightly/std/collections/hash_set/struct.Drain.html

[collections::hash_set::HashSet::drain]: http://doc.rust-lang.org/nightly/std/collections/hash_set/struct.HashSet.html#method.drain

[fs::DirBuilder::create]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html#method.create

[fs::DirBuilder::new]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html#method.new

[fs::DirBuilder::recursive]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html#method.recursive

[fs::DirBuilder]: http://doc.rust-lang.org/nightly/std/fs/struct.DirBuilder.html

[os::unix::fs::DirBuilderExt::mode]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.DirBuilderExt.html#tymethod.mode

[os::unix::fs::DirBuilderExt]: http://doc.rust-lang.org/nightly/std/os/unix/fs/trait.DirBuilderExt.html

[string::Drain]: http://doc.rust-lang.org/nightly/std/string/struct.Drain.html

[string::String::drain]: http://doc.rust-lang.org/nightly/std/string/struct.String.html#method.drain

[vec::Drain]: http://doc.rust-lang.org/nightly/std/vec/struct.Drain.html

[vec::Vec::drain]: http://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.drain

[vec_deque::Drain]: http://doc.rust-lang.org/nightly/std/collections/vec_deque/struct.Drain.html

[vec_deque::VecDeque::drain]: http://doc.rust-lang.org/nightly/std/collections/vec_deque/struct.VecDeque.html#method.drain