Rust 1.15.0

Released on February 2, 2017

What's Changed

Basic procedural macros allowing custom #[derive], aka "macros 1.1", are
[Tuple structs may be empty. Unary and empty tuple structs may be instantiated
[A number of minor changes to name resolution have been activated][37127].
[In macro_rules, path fragments can now be parsed as type parameter
[?Sized can be used in where clauses][37791]
[There is now a limit on the size of monomorphized types and it can be

[On Windows, the compiler will apply dllimport attributes when linking to
[Rust-ABI symbols are no longer exported from cdylibs][38117]
[The --test flag works with procedural macro crates][38107]
[Fix extern "aapcs" fn ABI][37814]
[The -C no-stack-check flag is deprecated][37636]. It does nothing.
[The format! expander recognizes incorrect printf and shell-style
[Only report one error for all unused imports in an import list][37456]

[std::iter::Iterator::min_by]
[std::iter::Iterator::max_by]
[std::os::*::fs::FileExt]
[std::sync::atomic::Atomic*::get_mut]
[std::sync::atomic::Atomic*::into_inner]
[std::vec::IntoIter::as_slice]
[std::vec::IntoIter::as_mut_slice]
[std::sync::mpsc::Receiver::try_iter]
[std::os::unix::process::CommandExt::before_exec]
[std::rc::Rc::strong_count]
[std::rc::Rc::weak_count]
[std::sync::Arc::strong_count]
[std::sync::Arc::weak_count]
[std::char::encode_utf8]
[std::char::encode_utf16]
[std::cell::Ref::clone]
[std::io::Take::into_inner]
[The standard sorting algorithm has been rewritten for dramatic performance
[Iterator::nth no longer has a Sized bound][38134]
[Extend<&T> is specialized for Vec where T: Copy][38182] to improve
[chars().count() is much faster][37888] and so are [chars().last()
[Fix ARM Objective-C ABI in std::env::args][38146]
[Chinese characters display correctly in fmt::Debug][37855]
[Derive Default for Duration][37699]
[Support creation of anonymous pipes on WinXP/2k][37677]
[mpsc::RecvTimeoutError implements Error][37527]
[Don't pass overlapped handles to processes][38835]

[In this release, Cargo build scripts no longer have access to the OUT_DIR
[Add --all flag to cargo test][cargo/3221]
[Compile statically against the MSVC CRT][cargo/3363]
[Mix feature flags into fingerprint/metadata shorthash][cargo/3102]
[Link OpenSSL statically on OSX][cargo/3311]
[Apply new fingerprinting to build dir outputs][cargo/3310]
[Test for bad path overrides with summaries][cargo/3336]
[Require cargo install --vers to take a semver version][cargo/3338]
[Fix retrying crate downloads for network errors][cargo/3348]
[Implement string lookup for build.rustflags config key][cargo/3356]
[Emit more info on --message-format=json][cargo/3319]
[Assume build.rs in the same directory as Cargo.toml is a build script][cargo/3361]
[Don't ignore errors in workspace manifest][cargo/3409]
[Fix --message-format JSON when rustc emits non-JSON warnings][cargo/3410]
[Test runners (binaries built with --test) now support a --list argument
[Test runners now support a --exact argument that makes the test filter
[rustdoc supports a --playground-url flag][37763]
[rustdoc provides more details about #[should_panic] errors][37749]

[A number of minor changes to name resolution have been activated][37127].
[In this release, Cargo build scripts no longer have access to the OUT_DIR
[Higher-ranked lifetimes are no longer allowed to appear _only_ in associated
[The semantics relating modules to file system directories are changing in
[Rust-ABI symbols are no longer exported from cdylibs][38117]
[Once Peekable peeks a None it will return that None without re-querying

[Avoid unnecessary mk_ty calls in Ty::super_fold_with][37705]
[Avoid more unnecessary mk_ty calls in Ty::super_fold_with][37979]
[Don't clone in UnificationTable::probe][37848]
[Remove scope_auxiliary to cut RSS by 10%][37764]
[Use small vectors in type walker][37760]
[Macro expansion performance was improved][37701]
[Change HirVec> to HirVec in hir::Expr][37642]
[Replace FNV with a faster hash function][37229]
[The Rust build system is now written in Rust][37817]. The Makefiles may
[Rust supports i686-unknown-openbsd][38086]. Tier 3 support. No testing or
[Rust supports the MSP430][37627]. Tier 3 support. No testing or releases.
[Rust supports the ARMv5TE architecture][37615]. Tier 3 support. No testing or

Full Changelog

Language

--------

* Basic procedural macros allowing custom #[derive], aka "macros 1.1", are

stable. This allows popular code-generating crates like Serde and Diesel to

work ergonomically. [RFC 1681].

* [Tuple structs may be empty. Unary and empty tuple structs may be instantiated

with curly braces][36868]. Part of [RFC 1506].

* [A number of minor changes to name resolution have been activated][37127].

They add up to more consistent semantics, allowing for future evolution of

Rust macros. Specified in [RFC 1560], see its section on ["changes"] for

details of what is different. The breaking changes here have been transitioned

through the [legacy_imports] lint since 1.14, with no known regressions.

* [In macro_rules, path fragments can now be parsed as type parameter

bounds][38279]

* [?Sized can be used in where clauses][37791]

* [There is now a limit on the size of monomorphized types and it can be

modified with the #![type_size_limit] crate attribute, similarly to

the #![recursion_limit] attribute][37789]

Compiler

--------

* [On Windows, the compiler will apply dllimport attributes when linking to

extern functions][37973]. Additional attributes and flags can control which

library kind is linked and its name. [RFC 1717].

* [Rust-ABI symbols are no longer exported from cdylibs][38117]

* [The --test flag works with procedural macro crates][38107]

* [Fix extern "aapcs" fn ABI][37814]

* [The -C no-stack-check flag is deprecated][37636]. It does nothing.

* [The format! expander recognizes incorrect printf and shell-style

formatting directives and suggests the correct format][37613].

* [Only report one error for all unused imports in an import list][37456]

Compiler Performance

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

* [Avoid unnecessary mk_ty calls in Ty::super_fold_with][37705]

* [Avoid more unnecessary mk_ty calls in Ty::super_fold_with][37979]

* [Don't clone in UnificationTable::probe][37848]

* [Remove scope_auxiliary to cut RSS by 10%][37764]

* [Use small vectors in type walker][37760]

* [Macro expansion performance was improved][37701]

* [Change HirVec> to HirVec in hir::Expr][37642]

* [Replace FNV with a faster hash function][37229]

Stabilized APIs

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

* [std::iter::Iterator::min_by]

* [std::iter::Iterator::max_by]

[std::os::::fs::FileExt] [std::sync::atomic::Atomic::get_mut] [std::sync::atomic::Atomic::into_inner]

* [std::vec::IntoIter::as_slice]

* [std::vec::IntoIter::as_mut_slice]

* [std::sync::mpsc::Receiver::try_iter]

* [std::os::unix::process::CommandExt::before_exec]

* [std::rc::Rc::strong_count]

* [std::rc::Rc::weak_count]

* [std::sync::Arc::strong_count]

* [std::sync::Arc::weak_count]

* [std::char::encode_utf8]

* [std::char::encode_utf16]

* [std::cell::Ref::clone]

* [std::io::Take::into_inner]

Libraries

---------

* [The standard sorting algorithm has been rewritten for dramatic performance

improvements][38192]. It is a hybrid merge sort, drawing influences from

Timsort. Previously it was a naive merge sort.

* [Iterator::nth no longer has a Sized bound][38134]

* [Extend<&T> is specialized for Vec where T: Copy][38182] to improve

performance.

* [chars().count() is much faster][37888] and so are [chars().last()

and char_indices().last()][37882]

* [Fix ARM Objective-C ABI in std::env::args][38146]

* [Chinese characters display correctly in fmt::Debug][37855]

* [Derive Default for Duration][37699]

* [Support creation of anonymous pipes on WinXP/2k][37677]

* [mpsc::RecvTimeoutError implements Error][37527]

* [Don't pass overlapped handles to processes][38835]

Cargo

-----

* [In this release, Cargo build scripts no longer have access to the OUT_DIR

environment variable at build time via env!("OUT_DIR")][cargo/3368]. They

should instead check the variable at runtime with std::env. That the value

was set at build time was a bug, and incorrect when cross-compiling. This

change is known to cause breakage.

* [Add --all flag to cargo test][cargo/3221]

* [Compile statically against the MSVC CRT][cargo/3363]

* [Mix feature flags into fingerprint/metadata shorthash][cargo/3102]

* [Link OpenSSL statically on OSX][cargo/3311]

* [Apply new fingerprinting to build dir outputs][cargo/3310]

* [Test for bad path overrides with summaries][cargo/3336]

* [Require cargo install --vers to take a semver version][cargo/3338]

* [Fix retrying crate downloads for network errors][cargo/3348]

* [Implement string lookup for build.rustflags config key][cargo/3356]

* [Emit more info on --message-format=json][cargo/3319]

* [Assume build.rs in the same directory as Cargo.toml is a build script][cargo/3361]

* [Don't ignore errors in workspace manifest][cargo/3409]

* [Fix --message-format JSON when rustc emits non-JSON warnings][cargo/3410]

Tooling

-------

* [Test runners (binaries built with --test) now support a --list argument

that lists the tests it contains][38185]

* [Test runners now support a --exact argument that makes the test filter

match exactly, instead of matching only a substring of the test name][38181]

* [rustdoc supports a --playground-url flag][37763]

* [rustdoc provides more details about #[should_panic] errors][37749]

Misc

----

* [The Rust build system is now written in Rust][37817]. The Makefiles may

continue to be used in this release by passing --disable-rustbuild to the

configure script, but they will be deleted soon. Note that the new build

system uses a different on-disk layout that will likely affect any scripts

building Rust.

* [Rust supports i686-unknown-openbsd][38086]. Tier 3 support. No testing or

releases.

* [Rust supports the MSP430][37627]. Tier 3 support. No testing or releases.

* [Rust supports the ARMv5TE architecture][37615]. Tier 3 support. No testing or

releases.

Compatibility Notes

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