Rust 1.16.0

Language

• The compiler's dead_code lint now accounts for type aliases.
• Uninhabitable enums (those without any variants) no longer permit wildcard match patterns
• Clean up semantics of self in an import list
• Self may appear in impl headers
• Self may appear in struct expressions

Compiler

• rustc now supports --emit=metadata, which causes rustc to emit a .rmeta file containing only crate metadata. This can be used by tools like the Rust Language Service to perform metadata-only builds.
• Levenshtein based typo suggestions now work in most places, while previously they worked only for fields and sometimes for local variables. Together with the overhaul of "no resolution"/"unexpected resolution" errors (#38154) they result in large and systematic improvement in resolution diagnostics.
• Fix transmute::<T, U> where T requires a bigger alignment than U
• rustc: use -Xlinker when specifying an rpath with ',' in it
• rustc no longer attempts to provide "consider using an explicit lifetime" suggestions. They were inaccurate.

Stabilized APIs

• VecDeque::truncate
• VecDeque::resize
• String::insert_str
• Duration::checked_add
• Duration::checked_sub
• Duration::checked_div
• Duration::checked_mul
• str::replacen
• str::repeat
• SocketAddr::is_ipv4
• SocketAddr::is_ipv6
• IpAddr::is_ipv4
• IpAddr::is_ipv6
• Vec::dedup_by
• Vec::dedup_by_key
• Result::unwrap_or_default
• <*const T>::wrapping_offset
• <*mut T>::wrapping_offset
• CommandExt::creation_flags
• File::set_permissions
• String::split_off

Libraries

• [T]::binary_search and [T]::binary_search_by_key now take their argument by Borrow parameter
• All public types in std implement Debug
• IpAddr implements From<Ipv4Addr> and From<Ipv6Addr>
• Ipv6Addr implements From<[u16; 8]>
• Ctrl-Z returns from Stdin.read() when reading from the console on Windows
• std: Fix partial writes in LineWriter
• std: Clamp max read/write sizes on Unix
• Use more specific panic message for &str slicing errors
• TcpListener::set_only_v6 is deprecated. This functionality cannot be achieved in std currently.
• writeln!, like println!, now accepts a form with no string or formatting arguments, to just print a newline
• Implement iter::Sum and iter::Product for Result
• Reduce the size of static data in std_unicode::tables
• char::EscapeDebug, EscapeDefault, EscapeUnicode, CaseMappingIter, ToLowercase, ToUppercase, implement Display
• Duration implements Sum
• String implements ToSocketAddrs

Cargo

• The cargo check command does a type check of a project without building it
• crates.io will display CI badges from Travis and AppVeyor, if specified in Cargo.toml
• crates.io will display categories listed in Cargo.toml
• Compilation profiles accept integer values for debug, in addition to true and false. These are passed to rustc as the value to -C debuginfo
• Implement cargo --version --verbose
• All builds now output 'dep-info' build dependencies compatible with make and ninja
• Build all workspace members with build --all
• Document all workspace members with doc --all
• Path deps outside workspace are not members

Misc

• rustdoc has a --sysroot argument that, like rustc, specifies the path to the Rust implementation
• The armv7-linux-androideabi target no longer enables NEON extensions, per Google's ABI guide
• The stock standard library can be compiled for Redox OS
• Rust has initial SPARC support. Tier 3. No builds available.
• Rust has experimental support for Nvidia PTX. Tier 3. No builds available.
• Fix backtraces on i686-pc-windows-gnu by disabling FPO

Compatibility Notes

• Uninhabitable enums (those without any variants) no longer permit wildcard match patterns
• In this release, references to uninhabited types can not be pattern-matched. This was accidentally allowed in 1.15.
• The compiler's dead_code lint now accounts for type aliases.
• Ctrl-Z returns from Stdin.read() when reading from the console on Windows
• Clean up semantics of self in an import list
• Reimplemented lifetime elision. This change was almost entirely compatible with existing code, but it did close a number of small bugs and loopholes, as well as being more accepting in some other cases.

Rust 1.15.1

• Fix IntoIter::as_mut_slice's signature
• Compile compiler builtins with -fPIC on 32-bit platforms

Rust 1.15.0

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. Part of RFC 1506.
• A number of minor changes to name resolution have been activated. 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
• ?Sized can be used in where clauses
• 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

Compiler

• On Windows, the compiler will apply dllimport attributes when linking to extern functions. 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
• The --test flag works with procedural macro crates
• Fix extern "aapcs" fn ABI
• The -C no-stack-check flag is deprecated. It does nothing.
• The format! expander recognizes incorrect printf and shell-style formatting directives and suggests the correct format.
• Only report one error for all unused imports in an import list

Compiler Performance

• Avoid unnecessary mk_ty calls in Ty::super_fold_with
• Avoid more unnecessary mk_ty calls in Ty::super_fold_with
• Don't clone in UnificationTable::probe
• Remove scope_auxiliary to cut RSS by 10%
• Use small vectors in type walker
• Macro expansion performance was improved
• Change HirVec<P<T>> to HirVec<T> in hir::Expr
• Replace FNV with a faster hash function

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. 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
• Extend<&T> is specialized for Vec where T: Copy to improve performance.
• chars().count() is much faster and so are chars().last() and char_indices().last()
• Fix ARM Objective-C ABI in std::env::args
• Chinese characters display correctly in fmt::Debug
• Derive Default for Duration
• Support creation of anonymous pipes on WinXP/2k
• mpsc::RecvTimeoutError implements Error
• Don't pass overlapped handles to processes

Cargo

• In this release, Cargo build scripts no longer have access to the OUT_DIR environment variable at build time via env!("OUT_DIR"). 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
• Compile statically against the MSVC CRT
• Mix feature flags into fingerprint/metadata shorthash
• Link OpenSSL statically on OSX
• Apply new fingerprinting to build dir outputs
• Test for bad path overrides with summaries
• Require cargo install --vers to take a semver version
• Fix retrying crate downloads for network errors
• Implement string lookup for build.rustflags config key
• Emit more info on --message-format=json
• Assume build.rs in the same directory as Cargo.toml is a build script
• Don't ignore errors in workspace manifest
• Fix --message-format JSON when rustc emits non-JSON warnings

Tooling

• Test runners (binaries built with --test) now support a --list argument that lists the tests it contains
• Test runners now support a --exact argument that makes the test filter match exactly, instead of matching only a substring of the test name
• rustdoc supports a --playground-url flag
• rustdoc provides more details about #[should_panic] errors

Misc

• The Rust build system is now written in Rust. 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. Tier 3 support. No testing or releases.
• Rust supports the MSP430. Tier 3 support. No testing or releases.
• Rust supports the ARMv5TE architecture. Tier 3 support. No testing or releases.

Compatibility Notes

• A number of minor changes to name resolution have been activated. 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 [`lega...

Rust 1.14.0

Language

• .. matches multiple tuple fields in enum variants, structs and tuples. RFC 1492.
• Safe fn items can be coerced to unsafe fn pointers
• use * and use ::* both glob-import from the crate root
• It's now possible to call a Vec<Box<Fn()>> without explicit dereferencing

Compiler

• Mark enums with non-zero discriminant as non-zero
• Lower-case static mut names are linted like other statics and consts
• Fix ICE on some macros in const integer positions (e.g. [u8; m!()])
• Improve error message and snippet for "did you mean x"
• Add a panic-strategy field to the target specification
• Include LLVM version in --version --verbose

Compile-time Optimizations

• Improve macro expansion performance
• Shrink Expr_::ExprInlineAsm
• Replace all uses of SHA-256 with BLAKE2b
• Reduce the number of bytes hashed by IchHasher
• Avoid more allocations when compiling html5ever
• Use SmallVector in CombineFields::instantiate
• Avoid some allocations in the macro parser
• Use a faster deflate setting
• Add ArrayVec and AccumulateVec to reduce heap allocations during interning of slices
• Optimize write_metadata
• Don't process obligation forest cycles when stalled
• Avoid many CrateConfig clones
• Optimize Substs::super_fold_with
• Optimize ObligationForest's NodeState handling
• Speed up plug_leaks

Libraries

• println!(), with no arguments, prints newline. Previously, an empty string was required to achieve the same.
• Wrapping impls standard binary and unary operators, as well as the Sum and Product iterators
• Implement From<Cow<str>> for String and From<Cow<[T]>> for Vec<T>
• Improve fold performance for chain, cloned, map, and VecDeque iterators
• Improve SipHasher performance on small values
• Add Iterator trait TrustedLen to enable better FromIterator / Extend
• Expand .zip() specialization to .map() and .cloned()
• ReadDir implements Debug
• Implement RefUnwindSafe for atomic types
• Specialize Vec::extend to Vec::extend_from_slice
• Avoid allocations in Decoder::read_str
• io::Error implements From<io::ErrorKind>
• Impl Debug for raw pointers to unsized data
• Don't reuse HashMap random seeds
• The internal memory layout of HashMap is more cache-friendly, for significant improvements in some operations
• HashMap uses less memory on 32-bit architectures
• Impl Add<{str, Cow<str>}> for Cow<str>

Cargo

• Expose rustc cfg values to build scripts
• Allow cargo to work with read-only CARGO_HOME
• Fix passing --features when testing multiple packages
• Use a single profile set per workspace
• Load replace sections from lock files
• Ignore panic configuration for test/bench profiles

Tooling

• rustup is the recommended Rust installation method
• This release includes host (rustc) builds for Linux on MIPS, PowerPC, and S390x. These are tier 2 platforms and may have major defects. Follow the instructions on the website to install, or add the targets to an existing installation with rustup target add. The new target triples are:
  • mips-unknown-linux-gnu
  • mipsel-unknown-linux-gnu
  • mips64-unknown-linux-gnuabi64
  • mips64el-unknown-linux-gnuabi64
  • powerpc-unknown-linux-gnu
  • powerpc64-unknown-linux-gnu
  • powerpc64le-unknown-linux-gnu
  • s390x-unknown-linux-gnu
• This release includes target (std) builds for ARM Linux running MUSL libc. These are tier 2 platforms and may have major defects. Add the following triples to an existing rustup installation with rustup target add:
  • arm-unknown-linux-musleabi
  • arm-unknown-linux-musleabihf
  • armv7-unknown-linux-musleabihf
• This release includes experimental support for WebAssembly, via the wasm32-unknown-emscripten target. This target is known to have major defects. Please test, report, and fix.
• rustup no longer installs documentation by default. Run rustup component add rust-docs to install.
• Fix line stepping in debugger
• Enable line number debuginfo in releases

Misc

• Disable jemalloc on aarch64/powerpc/mips
• Add support for Fuchsia OS
• Detect local-rebuild by only MAJOR.MINOR version

Compatibility Notes

• A number of forward-compatibility lints used by the compiler to gradually introduce language changes have been converted to deny by default:
  • "use of inaccessible extern crate erroneously allowed"
  • "type parameter default erroneously allowed in invalid location"
  • "detects super or self keywords at the beginning of global path"
  • "two overlapping inherent impls define an item with the same name were erroneously allowed"
  • "floating-point constants cannot be used in patterns"
  • "constants of struct or enum type can only be used in a pattern if the struct or enum has #[derive(PartialEq, Eq)]"
  • "lifetimes or labels named '_ were erroneously allowed"
• Prohibit patterns in trait methods without bodies
• The atomic Ordering enum may not be matched exhaustively
• Future-proofing #[no_link] breaks some obscure cases
• The $crate macro variable is accepted in fewer locations
• Impls specifying extra region requirements beyond the trait they implement are rejected
• Enums may not be unsized. Unsized enums are intended to work but never have. For now they are forbidden.
• Enforce the shadowing restrictions from RFC 1560 for today's macros

Rust 1.13.0

Language

• Stabilize the ? operator. ? is a simple way to propagate errors, like the try! macro, described in RFC 0243.
• Stabilize macros in type position. Described in RFC 873.
• Stabilize attributes on statements. Described in RFC 0016.
• Fix #[derive] for empty tuple structs/variants
• Fix lifetime rules for 'if' conditions
• Avoid loading and parsing unconfigured non-inline modules

Compiler

• Add the -C link-arg argument
• Remove the old AST-based backend from rustc_trans
• Don't enable NEON by default on armv7 Linux
• Fix debug line number info for macro expansions
• Do not emit "class method" debuginfo for types that are not DICompositeType
• Warn about multiple conflicting #[repr] hints
• When sizing DST, don't double-count nested struct prefixes
• Default RUST_MIN_STACK to 16MiB for now
• Improve rlib metadata format. Reduces rlib size significantly.
• Reject macros with empty repetitions to avoid infinite loop
• Expand macros without recursing to avoid stack overflows

Diagnostics

• Replace macro backtraces with labeled local uses
• Improve error message for misplaced doc comments
• Buffer unix and lock windows to prevent message interleaving
• Update lifetime errors to specifically note temporaries
• Special case a few colors for Windows
• Suggest use self when such an import resolves
• Be more specific when type parameter shadows primitive type
• Many minor improvements

Compile-time Optimizations

• Compute and cache HIR hashes at beginning
• Don't hash types in loan paths
• Cache projections in trans
• Optimize the parser's last token handling
• Only instantiate #[inline] functions in codegen units referencing them. This leads to big improvements in cases where crates export define many inline functions without using them directly.
• Lazily allocate TypedArena's first chunk
• Don't allocate during default HashSet creation

Stabilized APIs

• checked_abs
• wrapping_abs
• overflowing_abs
• RefCell::try_borrow
• RefCell::try_borrow_mut

Libraries

• Add assert_ne! and debug_assert_ne!
• Make vec_deque::Drain, hash_map::Drain, and hash_set::Drain covariant
• Implement AsRef<[T]> for std::slice::Iter
• Implement Debug for std::vec::IntoIter
• CString: avoid excessive growth just to 0-terminate
• Implement CoerceUnsized for {Cell, RefCell, UnsafeCell}
• Use arc4rand on FreeBSD
• memrchr: Correct aligned offset computation
• Improve Demangling of Rust Symbols
• Use monotonic time in condition variables
• Implement Debug for std::path::{Components,Iter}
• Implement conversion traits for char
• Fix illegal instruction caused by overflow in channel cloning
• Zero first byte of CString on drop
• Inherit overflow checks for sum and product
• Add missing Eq implementations
• Implement Debug for DirEntry
• When getaddrinfo returns EAI_SYSTEM retrieve actual error from errno
• SipHasher is deprecated. Use DefaultHasher.
• Implement more traits for std::io::ErrorKind
• Optimize BinaryHeap bounds checking
• Work around pointer aliasing issue in Vec::extend_from_slice, extend_with_element
• Fix overflow checking in unsigned pow()

Cargo

• This release includes security fixes to both curl and OpenSSL.
• Fix transitive doctests when panic=abort
• Add --all-features flag to cargo
• Reject path-based dependencies in cargo package
• Don't parse the home directory more than once
• Don't try to generate Cargo.lock on empty workspaces
• Update OpenSSL to 1.0.2j
• Add license and license_file to cargo metadata output
• Make crates-io registry URL optional in config; ignore all changes to source.crates-io
• Don't download dependencies from other platforms
• Build transitive dev-dependencies when needed
• Add support for per-target rustflags in .cargo/config
• Avoid updating registry when adding existing deps
• Warn about path overrides that won't work
• Use workspaces during cargo install
• Leak mspdbsrv.exe processes on Windows
• Add --message-format flag
• Pass target environment for rustdoc
• Use CommandExt::exec for cargo run on Unix
• Update curl and curl-sys
• Call rustdoc test with the correct cfg flags of a package

Tooling

• rustdoc: Add the --sysroot argument
• rustdoc: Fix a couple of issues with the search results
• rustdoc: remove the ! from macro URLs and titles
• gdb: Fix pretty-printing special-cased Rust types
• rustdoc: Filter more incorrect methods inherited through Deref

Misc

• Remove unmaintained style guide
• Add s390x support
• Initial work at Haiku OS support
• Add mips-uclibc targets
• Crate-ify compiler-rt into compiler-builtins
• Add rustc version info (git hash + date) to dist tarball
• Many documentation improvements

Compatibility Notes

• SipHasher is deprecated. Use DefaultHasher.
• Deny (by default) transmuting from fn item types to pointer-sized types. Continuing the long transition to zero-sized fn items, per [RFC 401](https://github.com/rust-lang/rfcs/blob/master/text/0...

Rust 1.12.1

Regression Fixes

• ICE: 'rustc' panicked at 'assertion failed: concrete_substs.is_normalized_for_trans()' #36381
• Confusion with double negation and booleans
• rustc 1.12.0 fails with SIGSEGV in release mode (syn crate 0.8.0)
• Rustc 1.12.0 Windows build of ethcore crate fails with LLVM error
• 1.12.0: High memory usage when linking in release mode with debug info
• Corrupted memory after updated to 1.12
• "Let NullaryConstructor = something;" causes internal compiler error: "tried to overwrite interned AdtDef"
• Fix ICE: inject bitcast if types mismatch for invokes/calls/stores
• debuginfo: Handle spread_arg case in MIR-trans in a more stable way.

Rust 1.12.0

Highlights

• rustc translates code to LLVM IR via its own "middle" IR (MIR). This translation pass is far simpler than the previous AST->LLVM pass, and creates opportunities to perform new optimizations directly on the MIR. It was previously described on the Rust blog.
• rustc presents a new, more readable error format, along with machine-readable JSON error output for use by IDEs. Most common editors supporting Rust have been updated to work with it. It was previously described on the Rust blog.

Compiler

• rustc translates code to LLVM IR via its own "middle" IR (MIR). This translation pass is far simpler than the previous AST->LLVM pass, and creates opportunities to perform new optimizations directly on the MIR. It was previously described on the Rust blog.
• Print the Rust target name, not the LLVM target name, with --print target-list
• The computation of TypeId is correct in some cases where it was previously producing inconsistent results
• The mips-unknown-linux-gnu target uses hardware floating point by default
• The rustc arguments, --print target-cpus, --print target-features, --print relocation-models, and --print code-models print the available options to the -C target-cpu, -C target-feature, -C relocation-model and -C code-model code generation arguments
• rustc supports three new MUSL targets on ARM: arm-unknown-linux-musleabi, arm-unknown-linux-musleabihf, and armv7-unknown-linux-musleabihf. These targets produce statically-linked binaries. There are no binary release builds yet though.

Diagnostics

• rustc presents a new, more readable error format, along with machine-readable JSON error output for use by IDEs. Most common editors supporting Rust have been updated to work with it. It was previously described on the Rust blog.
• In error descriptions, references are now described in plain English, instead of as "&-ptr"
• In error type descriptions, unknown numeric types are named {integer} or {float} instead of _
• rustc emits a clearer error when inner attributes follow a doc comment

Language

• macro_rules! invocations can be made within macro_rules! invocations
• macro_rules! meta-variables are hygienic
• macro_rules! tt matchers can be reparsed correctly, making them much more useful
• macro_rules! stmt matchers correctly consume the entire contents when inside non-braces invocations
• Semicolons are properly required as statement delimiters inside macro_rules! invocations
• cfg_attr works on path attributes

Stabilized APIs

• Cell::as_ptr
• RefCell::as_ptr
• IpAddr::is_unspecified
• IpAddr::is_loopback
• IpAddr::is_multicast
• Ipv4Addr::is_unspecified
• Ipv6Addr::octets
• LinkedList::contains
• VecDeque::contains
• ExitStatusExt::from_raw. Both on Unix and Windows.
• Receiver::recv_timeout
• RecvTimeoutError
• BinaryHeap::peek_mut
• PeekMut
• iter::Product
• iter::Sum
• OccupiedEntry::remove_entry
• VacantEntry::into_key

Libraries

• The format! macro and friends now allow a single argument to be formatted in multiple styles
• The lifetime bounds on [T]::binary_search_by and [T]::binary_search_by_key have been adjusted to be more flexible
• Option implements From for its contained type
• Cell, RefCell and UnsafeCell implement From for their contained type
• RwLock panics if the reader count overflows
• vec_deque::Drain, hash_map::Drain and hash_set::Drain are covariant
• vec::Drain and binary_heap::Drain are covariant
• Cow<str> implements FromIterator for char, &str and String
• Sockets on Linux are correctly closed in subprocesses via SOCK_CLOEXEC
• hash_map::Entry, hash_map::VacantEntry and hash_map::OccupiedEntry implement Debug
• btree_map::Entry, btree_map::VacantEntry and btree_map::OccupiedEntry implement Debug
• String implements AddAssign
• Variadic extern fn pointers implement the Clone, PartialEq, Eq, PartialOrd, Ord, Hash, fmt::Pointer, and fmt::Debug traits
• FileType implements Debug
• References to Mutex and RwLock are unwind-safe
• mpsc::sync_channel Receivers return any available message before reporting a disconnect
• Unicode definitions have been updated to 9.0
• env iterators implement DoubleEndedIterator

Cargo

• Support local mirrors of registries
• Add support for command aliases
• Allow opt-level="s" / opt-level="z" in profile overrides
• Make cargo doc --open --target work as expected
• Speed up noop registry updates
• Update OpenSSL
• Fix --panic=abort with plugins
• Always pass -C metadata to the compiler
• Fix depending on git repos with workspaces
• Add a --lib flag to cargo new
• Add http.cainfo for custom certs
• Indicate the compilation profile after compiling
• Allow enabling features for dependencies with --features
• Add --jobs flag to cargo package
• Add --dry-run to cargo publish
• Add support for RUSTDOCFLAGS

Performance

• panic::catch_unwind is more optimized
• panic::catch_unwind no longer accesses thread-local storage on entry

Tooling

• Test binaries now support a --test-threads argument to specify the number of threads used to run tests, and which acts the same as the RUST_TEST_THREADS environment variable
• The test runner now emits a warning when tests run over 60 seconds
• rustdoc: Fix methods in search results
• rust-lldb warns about unsupported versions of LLDB
• [Rust releases now come with source p...

Rust 1.11.0

Language

• Support nested cfg_attr attributes
• Allow statement-generating braced macro invocations at the end of blocks
• Macros can be expanded inside of trait definitions
• #[macro_use] works properly when it is itself expanded from a macro

Stabilized APIs

• BinaryHeap::append
• BTreeMap::append
• BTreeMap::split_off
• BTreeSet::append
• BTreeSet::split_off
• f32::to_degrees (in libcore - previously stabilized in libstd)
• f32::to_radians (in libcore - previously stabilized in libstd)
• f64::to_degrees (in libcore - previously stabilized in libstd)
• f64::to_radians (in libcore - previously stabilized in libstd)
• Iterator::sum
• Iterator::product
• Cell::get_mut
• RefCell::get_mut

Libraries

• The thread_local! macro supports multiple definitions in a single invocation, and can apply attributes
• Cow implements Default
• Wrapping implements binary, octal, lower-hex and upper-hex Display formatting
• The range types implement Hash
• lookup_host ignores unknown address types
• assert_eq! accepts a custom error message, like assert! does
• The main thread is now called "main" instead of "<main>"

Cargo

• Disallow specifying features of transitive deps
• Add color support for Windows consoles
• Fix harness = false on [lib] sections
• Don't panic when links contains a '.'
• Build scripts can emit warnings, and -vv prints warnings for all crates.
• Ignore file locks on OS X NFS mounts
• Don't warn about package.metadata keys. This provides room for expansion by arbitrary tools.
• Add support for cdylib crate types
• Prevent publishing crates when files are dirty
• Don't fetch all crates on clean
• Propagate --color option to rustc
• Fix cargo doc --open on Windows
• Improve autocompletion
• Configure colors of stderr as well as stdout

Performance

• Caching projections speeds up type check dramatically for some workloads
• The default HashMap hasher is SipHash 1-3 instead of SipHash 2-4 This hasher is faster, but is believed to provide sufficient protection from collision attacks.
• Comparison of Ipv4Addr is 10x faster

Rustdoc

• Fix empty implementation section on some module pages
• Fix inlined renamed re-exports in import lists
• Fix search result layout for enum variants and struct fields
• Fix issues with source links to external crates
• Fix redirect pages for renamed re-exports

Tooling

• rustc is better at finding the MSVC toolchain
• When emitting debug info, rustc emits frame pointers for closures, shims and glue, as it does for all other functions
• rust-lldb warns about unsupported versions of LLDB
• Many more errors have been given error codes and extended explanations
• API documentation continues to be improved, with many new examples

Misc

• rustc no longer hangs when dependencies recursively re-export submodules
• rustc requires LLVM 3.7+
• The 'How Safe and Unsafe Interact' chapter of The Rustonomicon was rewritten
• rustc support 16-bit pointer sizes. No targets use this yet, but it works toward AVR support.

Compatibility Notes

• consts and statics may not have unsized types
• The new follow-set rules that place restrictions on macro_rules! in order to ensure syntax forward-compatibility have been enabled This was an amendment to RFC 550, and has been a warning since 1.10.
• cfg attribute process has been refactored to fix various bugs. This causes breakage in some corner cases.

Rust 1.10.0

Language

• Copy types are required to have a trivial implementation of Clone. RFC 1521.
• Single-variant enums support the #[repr(..)] attribute.
• Fix #[derive(RustcEncodable)] in the presence of other encode methods.
• panic! can be converted to a runtime abort with the -C panic=abort flag. RFC 1513.
• Add a new crate type, 'cdylib'. cdylibs are dynamic libraries suitable for loading by non-Rust hosts. RFC 1510. Note that Cargo does not yet directly support cdylibs.

Stabilized APIs

• os::windows::fs::OpenOptionsExt::access_mode
• os::windows::fs::OpenOptionsExt::share_mode
• os::windows::fs::OpenOptionsExt::custom_flags
• os::windows::fs::OpenOptionsExt::attributes
• os::windows::fs::OpenOptionsExt::security_qos_flags
• os::unix::fs::OpenOptionsExt::custom_flags
• sync::Weak::new
• Default for sync::Weak
• panic::set_hook
• panic::take_hook
• panic::PanicInfo
• panic::PanicInfo::payload
• panic::PanicInfo::location
• panic::Location
• panic::Location::file
• panic::Location::line
• ffi::CStr::from_bytes_with_nul
• ffi::CStr::from_bytes_with_nul_unchecked
• ffi::FromBytesWithNulError
• fs::Metadata::modified
• fs::Metadata::accessed
• fs::Metadata::created
• sync::atomic::Atomic{Usize,Isize,Bool,Ptr}::compare_exchange
• sync::atomic::Atomic{Usize,Isize,Bool,Ptr}::compare_exchange_weak
• collections::{btree,hash}_map::{Occupied,Vacant,}Entry::key
• os::unix::net::{UnixStream, UnixListener, UnixDatagram, SocketAddr}
• SocketAddr::is_unnamed
• SocketAddr::as_pathname
• UnixStream::connect
• UnixStream::pair
• UnixStream::try_clone
• UnixStream::local_addr
• UnixStream::peer_addr
• UnixStream::set_read_timeout
• UnixStream::set_write_timeout
• UnixStream::read_timeout
• UnixStream::write_timeout
• UnixStream::set_nonblocking
• UnixStream::take_error
• UnixStream::shutdown
• Read/Write/RawFd impls for UnixStream
• UnixListener::bind
• UnixListener::accept
• UnixListener::try_clone
• UnixListener::local_addr
• UnixListener::set_nonblocking
• UnixListener::take_error
• UnixListener::incoming
• RawFd impls for UnixListener
• UnixDatagram::bind
• UnixDatagram::unbound
• UnixDatagram::pair
• UnixDatagram::connect
• UnixDatagram::try_clone
• UnixDatagram::local_addr
• UnixDatagram::peer_addr
• UnixDatagram::recv_from
• UnixDatagram::recv
• UnixDatagram::send_to
• UnixDatagram::send
• UnixDatagram::set_read_timeout
• UnixDatagram::set_write_timeout
• UnixDatagram::read_timeout
• UnixDatagram::write_timeout
• UnixDatagram::set_nonblocking
• UnixDatagram::take_error
• UnixDatagram::shutdown
• RawFd impls for UnixDatagram
• {BTree,Hash}Map::values_mut
• <[_]>::binary_search_by_key

Libraries

• The abs_sub method of floats is deprecated. The semantics of this minor method are subtle and probably not what most people want.
• Add implementation of Ord for Cell and RefCell where T: Ord.
• On Linux, if HashMaps can't be initialized with getrandom they will fall back to /dev/urandom temporarily to avoid blocking during early boot.
• Implemented negation for wrapping numerals.
• Implement Clone for binary_heap::IntoIter.
• Implement Display and Hash for std::num::Wrapping.
• Add Default implementation for &CStr, CString.
• Implement From<Vec<T>> and Into<Vec<T>> for VecDeque<T>.
• Implement Default for UnsafeCell, fmt::Error, Condvar, Mutex, RwLock.

Cargo

• Cargo.toml supports the profile.*.panic option. This controls the runtime behavior of the panic! macro and can be either "unwind" (the default), or "abort". RFC 1513.
• Don't throw away errors with -p arguments.
• Report status to stderr instead of stdout.
• Build scripts are passed a CARGO_MANIFEST_LINKS environment variable that corresponds to the links field of the manifest.
• Ban keywords from crate names.
• Canonicalize CARGO_HOME on Windows.
• Retry network requests. By default they are retried twice, which can be customized with the net.retry value in .cargo/config.
• [Don't print extra error info for failing subcommands](rust-lang/cargo#267...

Rust 1.9.0

Language

• The #[deprecated] attribute when applied to an API will generate warnings when used. The warnings may be suppressed with #[allow(deprecated)]. RFC 1270.
• fn item types are zero sized, and each fn names a unique type. This will break code that transmutes fns, so calling transmute on a fn type will generate a warning for a few cycles, then will be converted to an error.
• Field and method resolution understand visibility, so private fields and methods cannot prevent the proper use of public fields and methods.
• The parser considers unicode codepoints in the PATTERN_WHITE_SPACE category to be whitespace.

Stabilized APIs

• std::panic
• std::panic::catch_unwind (renamed from recover)
• std::panic::resume_unwind (renamed from propagate)
• std::panic::AssertUnwindSafe (renamed from AssertRecoverSafe)
• std::panic::UnwindSafe (renamed from RecoverSafe)
• str::is_char_boundary
• <*const T>::as_ref
• <*mut T>::as_ref
• <*mut T>::as_mut
• AsciiExt::make_ascii_uppercase
• AsciiExt::make_ascii_lowercase
• char::decode_utf16
• char::DecodeUtf16
• char::DecodeUtf16Error
• char::DecodeUtf16Error::unpaired_surrogate
• BTreeSet::take
• BTreeSet::replace
• BTreeSet::get
• HashSet::take
• HashSet::replace
• HashSet::get
• OsString::with_capacity
• OsString::clear
• OsString::capacity
• OsString::reserve
• OsString::reserve_exact
• OsStr::is_empty
• OsStr::len
• std::os::unix::thread
• RawPthread
• JoinHandleExt
• JoinHandleExt::as_pthread_t
• JoinHandleExt::into_pthread_t
• HashSet::hasher
• HashMap::hasher
• CommandExt::exec
• File::try_clone
• SocketAddr::set_ip
• SocketAddr::set_port
• SocketAddrV4::set_ip
• SocketAddrV4::set_port
• SocketAddrV6::set_ip
• SocketAddrV6::set_port
• SocketAddrV6::set_flowinfo
• SocketAddrV6::set_scope_id
• slice::copy_from_slice
• ptr::read_volatile
• ptr::write_volatile
• OpenOptions::create_new
• TcpStream::set_nodelay
• TcpStream::nodelay
• TcpStream::set_ttl
• TcpStream::ttl
• TcpStream::set_only_v6
• TcpStream::only_v6
• TcpStream::take_error
• TcpStream::set_nonblocking
• TcpListener::set_ttl
• TcpListener::ttl
• TcpListener::set_only_v6
• TcpListener::only_v6
• TcpListener::take_error
• TcpListener::set_nonblocking
• UdpSocket::set_broadcast
• UdpSocket::broadcast
• UdpSocket::set_multicast_loop_v4
• UdpSocket::multicast_loop_v4
• UdpSocket::set_multicast_ttl_v4
• UdpSocket::multicast_ttl_v4
• UdpSocket::set_multicast_loop_v6
• UdpSocket::multicast_loop_v6
• UdpSocket::set_multicast_ttl_v6
• UdpSocket::multicast_ttl_v6
• UdpSocket::set_ttl
• UdpSocket::ttl
• UdpSocket::set_only_v6
• UdpSocket::only_v6
• UdpSocket::join_multicast_v4
• UdpSocket::join_multicast_v6
• UdpSocket::leave_multicast_v4
• UdpSocket::leave_multicast_v6
• UdpSocket::take_error
• [`UdpSocket:...