Rust 1.3.0

* ~900 changes, numerous bugfixes

Highlights

----------

* The [new object lifetime defaults][nold] have been [turned

on][nold2] after a cycle of warnings about the change. Now types

like &'a Box (or &'a Rc, etc) will change from

being interpreted as &'a Box to &'a

Box.

* [The Rustonomicon][nom] is a new book in the official documentation

that dives into writing unsafe Rust.

* The [Duration] API, [has been stabilized][ds]. This basic unit of

timekeeping is employed by other std APIs, as well as out-of-tree

time crates.

Breaking Changes

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

* The [new object lifetime defaults][nold] have been [turned

on][nold2] after a cycle of warnings about the change.

* There is a known [regression][lr] in how object lifetime elision is

interpreted, the proper solution for which is undetermined.

* The #[prelude_import] attribute, an internal implementation

detail, was accidentally stabilized previously. [It has been put

behind the prelude_import feature gate][pi]. This change is

believed to break no existing code.

* The behavior of [size_of_val][dst1] and [align_of_val][dst2] is

[more sane for dynamically sized types][dst3]. Code that relied on

the previous behavior is thought to be broken.

* The dropck rules, which checks that destructors can't access

destroyed values, [have been updated][dropck] to match the

[RFC][dropckrfc]. This fixes some soundness holes, and as such will

cause some previously-compiling code to no longer build.

Language

--------

* The [new object lifetime defaults][nold] have been [turned

on][nold2] after a cycle of warnings about the change.

* Semicolons may now follow types and paths in

macros.

* The behavior of [size_of_val][dst1] and [align_of_val][dst2] is

[more sane for dynamically sized types][dst3]. Code that relied on

the previous behavior is not known to exist, and suspected to be

broken.

* 'static variables [may now be recursive][st].

* ref bindings choose between [Deref] and [DerefMut]

implementations correctly.

* The dropck rules, which checks that destructors can't access

destroyed values, [have been updated][dropck] to match the

[RFC][dropckrfc].

Libraries

---------

* The [Duration] API, [has been stabilized][ds], as well as the

std::time module, which presently contains only Duration.

* Box and Box<[T]> both implement Clone.

* The owned C string, [CString], implements [Borrow] and the

borrowed C string, [CStr], implements [ToOwned]. The two of

these allow C strings to be borrowed and cloned in generic code.

* [CStr] implements [Debug].

* [AtomicPtr] implements [Debug].

* [Error] trait objects [can be downcast to their concrete types][e]

in many common configurations, using the [is], [downcast],

[downcast_ref] and [downcast_mut] methods, similarly to the

[Any] trait.

* Searching for substrings now [employs the two-way algorithm][search]

instead of doing a naive search. This gives major speedups to a

number of methods, including [contains][sc], [find][sf],

[rfind][srf], [split][ss]. [starts_with][ssw] and

[ends_with][sew] are also faster.

* The performance of PartialEq for slices is [much faster][ps].

* The [Hash] trait offers the default method, [hash_slice], which

is overridden and optimized by the implementations for scalars.

The [Hasher] trait now has a number of specialized write_

methods for primitive types, for efficiency.

* The I/O-specific error type, [std::io::Error][ie], gained a set of

methods for accessing the 'inner error', if any: [get_ref][iegr],

[get_mut][iegm], [into_inner][ieii]. As well, the implementation

of [std::error::Error::cause][iec] also delegates to the inner

error.

* [process::Child][pc] gained the [id] method, which returns a

u32 representing the platform-specific process identifier.

* The [connect] method on slices is deprecated, replaced by the new

[join] method (note that both of these are on the unstable

[SliceConcatExt] trait, but through the magic of the prelude are

available to stable code anyway).

* The [Div] operator is implemented for [Wrapping] types.

* [DerefMut is implemented for String][dms].

* Performance of SipHash (the default hasher for HashMap) is

[better for long data][sh].

* [AtomicPtr] implements [Send].

* The [read_to_end] implementations for [Stdin] and [File]

are now [specialized to use uninitialized buffers for increased

performance][rte].

* Lifetime parameters of foreign functions [are now resolved

properly][f].

Misc

----

* Rust can now, with some coercion, [produce programs that run on

Windows XP][xp], though XP is not considered a supported platform.

* Porting Rust on Windows from the GNU toolchain to MSVC continues

([1][win1], [2][win2], [3][win3], [4][win4]). It is still not

recommended for use in 1.3, though should be fully-functional

in the [64-bit 1.4 beta][b14].

* On Fedora-based systems installation will [properly configure the

dynamic linker][fl].

* The compiler gained many new extended error descriptions, which can

be accessed with the --explain flag.

* The dropck pass, which checks that destructors can't access

destroyed values, [has been rewritten][27261]. This fixes some

soundness holes, and as such will cause some previously-compiling

code to no longer build.

* rustc now uses [LLVM to write archive files where possible][ar].

Eventually this will eliminate the compiler's dependency on the ar

utility.

* Rust has [preliminary support for i686 FreeBSD][26959] (it has long

supported FreeBSD on x86_64).

* The [unused_mut][lum], [unconditional_recursion][lur],

[improper_ctypes][lic], and [negate_unsigned][lnu] lints are

more strict.

* If landing pads are disabled (with -Z no-landing-pads), [panic!

will kill the process instead of leaking][nlp].

[Any]: http://doc.rust-lang.org/nightly/std/any/trait.Any.html

[AtomicPtr]: http://doc.rust-lang.org/nightly/std/sync/atomic/struct.AtomicPtr.html

[Borrow]: http://doc.rust-lang.org/nightly/std/borrow/trait.Borrow.html

[CStr]: http://doc.rust-lang.org/nightly/std/ffi/struct.CStr.html

[CString]: http://doc.rust-lang.org/nightly/std/ffi/struct.CString.html

[Debug]: http://doc.rust-lang.org/nightly/std/fmt/trait.Debug.html

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

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

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

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

[Error]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html

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

[Hash]: http://doc.rust-lang.org/nightly/std/hash/trait.Hash.html

[Hasher]: http://doc.rust-lang.org/nightly/std/hash/trait.Hasher.html

[Send]: http://doc.rust-lang.org/nightly/std/marker/trait.Send.html

[SliceConcatExt]: http://doc.rust-lang.org/nightly/std/slice/trait.SliceConcatExt.html

[Stdin]: http://doc.rust-lang.org/nightly/std/io/struct.Stdin.html

[ToOwned]: http://doc.rust-lang.org/nightly/std/borrow/trait.ToOwned.html

[Wrapping]: http://doc.rust-lang.org/nightly/std/num/struct.Wrapping.html

[connect]: http://doc.rust-lang.org/nightly/std/slice/trait.SliceConcatExt.html#method.connect

[downcast_mut]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.downcast_mut

[downcast_ref]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.downcast_ref

[downcast]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.downcast

[hash_slice]: http://doc.rust-lang.org/nightly/std/hash/trait.Hash.html#method.hash_slice

[id]: http://doc.rust-lang.org/nightly/std/process/struct.Child.html#method.id

[is]: http://doc.rust-lang.org/nightly/std/error/trait.Error.html#method.is

[join]: http://doc.rust-lang.org/nightly/std/slice/trait.SliceConcatExt.html#method.join

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

[ar]: https://github.com/rust-lang/rust/pull/26926

[b14]: https://static.rust-lang.org/dist/rust-beta-x86_64-pc-windows-msvc.msi

[dms]: https://github.com/rust-lang/rust/pull/26241

[27261]: https://github.com/rust-lang/rust/pull/27261

[dropckrfc]: https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md

[ds]: https://github.com/rust-lang/rust/pull/26818

[dst1]: http://doc.rust-lang.org/nightly/std/mem/fn.size_of_val.html

[dst2]: http://doc.rust-lang.org/nightly/std/mem/fn.align_of_val.html

[dst3]: https://github.com/rust-lang/rust/pull/27351

[e]: https://github.com/rust-lang/rust/pull/24793

[f]: https://github.com/rust-lang/rust/pull/26588

[26959]: https://github.com/rust-lang/rust/pull/26959

[fl]: https://github.com/rust-lang/rust-installer/pull/41

[ie]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html

[iec]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.cause

[iegm]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.get_mut

[iegr]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.get_ref

[ieii]: http://doc.rust-lang.org/nightly/std/io/struct.Error.html#method.into_inner

[lic]: https://github.com/rust-lang/rust/pull/26583

[lnu]: https://github.com/rust-lang/rust/pull/27026

[lr]: https://github.com/rust-lang/rust/issues/27248

[lum]: https://github.com/rust-lang/rust/pull/26378

[lur]: https://github.com/rust-lang/rust/pull/26783

[nlp]: https://github.com/rust-lang/rust/pull/27176

[nold2]: https://github.com/rust-lang/rust/pull/27045

[nold]: https://github.com/rust-lang/rfcs/blob/master/text/1156-adjust-default-object-bounds.md

[nom]: http://doc.rust-lang.org/nightly/nomicon/

[pc]: http://doc.rust-lang.org/nightly/std/process/struct.Child.html

[pi]: https://github.com/rust-lang/rust/pull/26699

[ps]: https://github.com/rust-lang/rust/pull/26884

[rte]: https://github.com/rust-lang/rust/pull/26950

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

[search]: https://github.com/rust-lang/rust/pull/26327

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

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

[sh]: https://github.com/rust-lang/rust/pull/27280

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

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

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

[st]: https://github.com/rust-lang/rust/pull/26630

[win1]: https://github.com/rust-lang/rust/pull/26569

[win2]: https://github.com/rust-lang/rust/pull/26741

[win3]: https://github.com/rust-lang/rust/pull/26741

[win4]: https://github.com/rust-lang/rust/pull/27210

[xp]: https://github.com/rust-lang/rust/pull/26569