Version 1.5.0 (2015-12-10)

• ~700 changes, numerous bugfixes

Highlights

• Stabilized APIs: BinaryHeap::from, BinaryHeap::into_sorted_vec, BinaryHeap::into_vec, Condvar::wait_timeout, FileTypeExt::is_block_device, FileTypeExt::is_char_device, FileTypeExt::is_fifo, FileTypeExt::is_socket, FileTypeExt, Formatter::alternate, Formatter::fill, Formatter::precision, Formatter::sign_aware_zero_pad, Formatter::sign_minus, Formatter::sign_plus, Formatter::width, Iterator::cmp, Iterator::eq, Iterator::ge, Iterator::gt, Iterator::le, Iterator::lt, Iterator::ne, Iterator::partial_cmp, Path::canonicalize, Path::exists, Path::is_dir, Path::is_file, Path::metadata, Path::read_dir, Path::read_link, Path::symlink_metadata, Utf8Error::valid_up_to, Vec::resize, VecDeque::as_mut_slices, VecDeque::as_slices, VecDeque::insert, VecDeque::shrink_to_fit, VecDeque::swap_remove_back, VecDeque::swap_remove_front, slice::split_first_mut, slice::split_first, slice::split_last_mut, slice::split_last, char::from_u32_unchecked, fs::canonicalize, str::MatchIndices, str::RMatchIndices, str::match_indices, str::rmatch_indices, str::slice_mut_unchecked, string::ParseError.
• Rust applications hosted on crates.io can be installed locally to ~/.cargo/bin with the cargo install command. Among other things this makes it easier to augment Cargo with new subcommands: when a binary named e.g. cargo-foo is found in $PATH it can be invoked as cargo foo.
• Crates with wildcard (*) dependencies will emit warnings when published. In 1.6 it will no longer be possible to publish crates with wildcard dependencies.

Breaking Changes

• The rules determining when a particular lifetime must outlive a particular value (known as 'dropck') have been modified to not rely on parametricity.
• Implementations of AsRef and AsMut were added to Box, Rc, and Arc. Because these smart pointer types implement Deref, this causes breakage in cases where the interior type contains methods of the same name.
• Correct a bug in Rc/Arc that caused dropck to be unaware that they could drop their content. Soundness fix.
• All method invocations are properly checked for well-formedness. Soundness fix.
• Traits whose supertraits contain Self are not object safe. Soundness fix.
• Target specifications support a no_default_libraries setting that controls whether -nodefaultlibs is passed to the linker, and in turn the is_like_windows setting no longer affects the -nodefaultlibs flag.
• #[derive(Show)], long-deprecated, has been removed.
• The #[inline] and #[repr] attributes can only appear in valid locations.
• Native libraries linked from the local crate are passed to the linker before native libraries from upstream crates.
• Two rarely-used attributes, #[no_debug] and #[omit_gdb_pretty_printer_section] are feature gated.
• Negation of unsigned integers, which has been a warning for several releases, is now behind a feature gate and will generate errors.
• The parser accidentally accepted visibility modifiers on enum variants, a bug which has been fixed.
• A bug was fixed that allowed use statements to import unstable features.

Language

• When evaluating expressions at compile-time that are not compile-time constants (const-evaluating expressions in non-const contexts), incorrect code such as overlong bitshifts and arithmetic overflow will generate a warning instead of an error, delaying the error until runtime. This will allow the const-evaluator to be expanded in the future backwards-compatibly.
• The improper_ctypes lint no longer warns about using isize and usize in FFI.

Libraries

• Arc<T> and Rc<T> are covariant with respect to T instead of invariant.
• Default is implemented for mutable slices.
• FromStr is implemented for SockAddrV4 and SockAddrV6.
• There are now From conversions between floating point types where the conversions are lossless.
• There are now From conversions between integer types where the conversions are lossless.
• fs::Metadata implements Clone.
• The parse method accepts a leading "+" when parsing integers.
• AsMut is implemented for Vec.
• The clone_from implementations for String and BinaryHeap have been optimized and no longer rely on the default impl.
• The extern "Rust", extern "C", unsafe extern "Rust" and unsafe extern "C" function types now implement Clone, PartialEq, Eq, PartialOrd, Ord, Hash, fmt::Pointer, and fmt::Debug for up to 12 arguments.
• Dropping Vecs is much faster in unoptimized builds when the element types don't implement Drop.
• A bug that caused in incorrect behavior when combining VecDeque with zero-sized types was resolved.
• PartialOrd for slices is faster.

Miscellaneous

• Crate metadata size was reduced by 20%.
• Improvements to code generation reduced the size of libcore by 3.3 MB and rustc's memory usage by 18MB.
• Improvements to deref translation increased performance in unoptimized builds.
• Various errors in trait resolution are deduplicated to only be reported once.
• Rust has preliminary support for rumprun kernels.
• Rust has preliminary support for NetBSD on amd64.