Rust 0.12.0

• ~1900 changes, numerous bugfixes

• Highlights

  • The introductory documentation (now called The Rust Guide) has been completely rewritten, as have a number of supplementary guides.
  • Rust's package manager, Cargo, continues to improve and is sometimes considered to be quite awesome.
  • Many API's in std have been reviewed and updated for consistency with the in-development Rust coding guidelines. The standard library documentation tracks stabilization progress.
  • Minor libraries have been moved out-of-tree to the rust-lang org on GitHub: uuid, semver, glob, num, hexfloat, fourcc. They can be installed with Cargo.
  • Lifetime elision allows lifetime annotations to be left off of function declarations in many common scenarios.
  • Rust now works on 64-bit Windows.

• Language

  • Indexing can be overloaded with the Index and IndexMut traits.
  • The if let construct takes a branch only if the let pattern matches, currently behind the 'if_let' feature gate.
  • 'where clauses', a more flexible syntax for specifying trait bounds that is more aesthetic, have been added for traits and free functions. Where clauses will in the future make it possible to constrain associated types, which would be impossible with the existing syntax.
  • A new slicing syntax (e.g. [0..4]) has been introduced behind the 'slicing_syntax' feature gate, and can be overloaded with the Slice or SliceMut traits.
  • The syntax for matching of sub-slices has been changed to use a postfix .. instead of prefix (.e.g. [a, b, c..]), for consistency with other uses of .. and to future-proof potential additional uses of the syntax.
  • The syntax for matching inclusive ranges in patterns has changed from 0..3 to 0...4 to be consistent with the exclusive range syntax for slicing.
  • Matching of sub-slices in non-tail positions (e.g. [a.., b, c]) has been put behind the 'advanced_slice_patterns' feature gate and may be removed in the future.
  • Components of tuples and tuple structs can be extracted using the value.0 syntax, currently behind the tuple_indexing feature gate.
  • The #[crate_id] attribute is no longer supported; versioning is handled by the package manager.
  • Renaming crate imports are now written extern crate foo as bar instead of extern crate bar = foo.
  • Renaming use statements are now written use foo as bar instead of use bar = foo.
  • let and match bindings and argument names in macros are now hygienic.
  • The new, more efficient, closure types ('unboxed closures') have been added under a feature gate, 'unboxed_closures'. These will soon replace the existing closure types, once higher-ranked trait lifetimes are added to the language.
  • move has been added as a keyword, for indicating closures that capture by value.
  • Mutation and assignment is no longer allowed in pattern guards.
  • Generic structs and enums can now have trait bounds.
  • The Share trait is now called Sync to free up the term 'shared' to refer to 'shared reference' (the default reference type.
  • Dynamically-sized types have been mostly implemented, unifying the behavior of fat-pointer types with the rest of the type system.
  • As part of dynamically-sized types, the Sized trait has been introduced, which qualifying types implement by default, and which type parameters expect by default. To specify that a type parameter does not need to be sized, write <Sized? T>. Most types are Sized, notable exceptions being unsized arrays ([T]) and trait types.
  • Closures can return !, as in || -> ! or proc() -> !.
  • Lifetime bounds can now be applied to type parameters and object types.
  • The old, reference counted GC type, Gc<T> which was once denoted by the @ sigil, has finally been removed. GC will be revisited in the future.

• Libraries

  • Library documentation has been improved for a number of modules.
  • Bit-vectors, collections::bitv has been modernized.
  • The url crate is deprecated in favor of http://github.com/servo/rust-url, which can be installed with Cargo.
  • Most I/O stream types can be cloned and subsequently closed from a different thread.
  • A std::time::Duration type has been added for use in I/O methods that rely on timers, as well as in the 'time' crate's Timespec arithmetic.
  • The runtime I/O abstraction layer that enabled the green thread scheduler to do non-thread-blocking I/O has been removed, along with the libuv-based implementation employed by the green thread scheduler. This will greatly simplify the future I/O work.
  • collections::btree has been rewritten to have a more idiomatic and efficient design.

• Tooling

  • rustdoc output now indicates the stability levels of API's.
  • The --crate-name flag can specify the name of the crate being compiled, like #[crate_name].
  • The -C metadata specifies additional metadata to hash into symbol names, and -C extra-filename specifies additional information to put into the output filename, for use by the package manager for versioning.
  • debug info generation has continued to improve and should be more reliable under both gdb and lldb.
  • rustc has experimental support for compiling in parallel using the -C codegen-units flag.
  • rustc no longer encodes rpath information into binaries by default.

• Misc

  • Stack usage has been optimized with LLVM lifetime annotations.
  • Official Rust binaries on Linux are more compatible with older kernels and distributions, built on CentOS 5.10.

Rust 0.11.0

• ~1700 changes, numerous bugfixes

• Language

  • ~[T] has been removed from the language. This type is superseded by the Vec type.
  • ~str has been removed from the language. This type is superseded by the String type.
  • ~T has been removed from the language. This type is superseded by the Box type.
  • @t has been removed from the language. This type is superseded by the standard library's std::gc::Gc type.
  • Struct fields are now all private by default.
  • Vector indices and shift amounts are both required to be a uint instead of any integral type.
  • Byte character, byte string, and raw byte string literals are now all supported by prefixing the normal literal with a b.
  • Multiple ABIs are no longer allowed in an ABI string
  • The syntax for lifetimes on closures/procedures has been tweaked slightly: <'a>|A, B|: 'b + K -> T
  • Floating point modulus has been removed from the language; however it is still provided by a library implementation.
  • Private enum variants are now disallowed.
  • The priv keyword has been removed from the language.
  • A closure can no longer be invoked through a &-pointer.
  • The use foo, bar, baz; syntax has been removed from the language.
  • The transmute intrinsic no longer works on type parameters.
  • Statics now allow blocks/items in their definition.
  • Trait bounds are separated from objects with + instead of : now.
  • Objects can no longer be read while they are mutably borrowed.
  • The address of a static is now marked as insignificant unless the #[inline(never)] attribute is placed it.
  • The #[unsafe_destructor] attribute is now behind a feature gate.
  • Struct literals are no longer allowed in ambiguous positions such as if, while, match, and for..in.
  • Declaration of lang items and intrinsics are now feature-gated by default.
  • Integral literals no longer default to int, and floating point literals no longer default to f64. Literals must be suffixed with an appropriate type if inference cannot determine the type of the literal.
  • The Box type is no longer implicitly borrowed to &mut T.
  • Procedures are now required to not capture borrowed references.

• Libraries

  • The standard library is now a "facade" over a number of underlying libraries. This means that development on the standard library should be speedier due to smaller crates, as well as a clearer line between all dependencies.
  • A new library, libcore, lives under the standard library's facade which is Rust's "0-assumption" library, suitable for embedded and kernel development for example.
  • A regex crate has been added to the standard distribution. This crate includes statically compiled regular expressions.
  • The unwrap/unwrap_err methods on Result require a Show bound for better error messages.
  • The return types of the std::comm primitives have been centralized around the Result type.
  • A number of I/O primitives have gained the ability to time out their operations.
  • A number of I/O primitives have gained the ability to close their reading/writing halves to cancel pending operations.
  • Reverse iterator methods have been removed in favor of rev() on their forward-iteration counterparts.
  • A bitflags! macro has been added to enable easy interop with C and management of bit flags.
  • A debug_assert! macro is now provided which is disabled when --cfg ndebug is passed to the compiler.
  • A graphviz crate has been added for creating .dot files.
  • The std::cast module has been migrated into std::mem.
  • The std::local_data api has been migrated from freestanding functions to being based on methods.
  • The Pod trait has been renamed to Copy.
  • jemalloc has been added as the default allocator for types.
  • The API for allocating memory has been changed to use proper alignment and sized deallocation
  • Connecting a TcpStream or binding a TcpListener is now based on a string address and a u16 port. This allows connecting to a hostname as opposed to an IP.
  • The Reader trait now contains a core method, read_at_least(), which correctly handles many repeated 0-length reads.
  • The process-spawning API is now centered around a builder-style Command struct.
  • The :? printing qualifier has been moved from the standard library to an external libdebug crate.
  • Eq/Ord have been renamed to PartialEq/PartialOrd. TotalEq/TotalOrd have been renamed to Eq/Ord.
  • The select/plural methods have been removed from format!. The escapes for { and } have also changed from { and } to {{ and }}, respectively.
  • The TaskBuilder API has been re-worked to be a true builder, and extension traits for spawning native/green tasks have been added.

• Tooling

  • All breaking changes to the language or libraries now have their commit message annotated with [breaking-change] to allow for easy discovery of breaking changes.
  • The compiler will now try to suggest how to annotate lifetimes if a lifetime-related error occurs.
  • Debug info continues to be improved greatly with general bug fixes and better support for situations like link time optimization (LTO).
  • Usage of syntax extensions when cross-compiling has been fixed.
  • Functionality equivalent to GCC & Clang's -ffunction-sections, -fdata-sections and --gc-sections has been enabled by default
  • The compiler is now stricter about where it will load module files from when a module is declared via mod foo;.
  • The #[phase(syntax)] attribute has been renamed to #[phase(plugin)]. Syntax extensions are now discovered via a "plugin registrar" type which will be extended in the future to other various plugins.
  • Lints have been restructured to allow for dynamically loadable lints.
  • A number of rustdoc improvements:
    • The HTML output has been visually redesigned.
    • Markdown is now powered by hoedown instead of sundown.
    • Searching heuristics have been greatly improved.
    • The search index has been reduced in size by a great amount.
    • Cross-crate documentation via pub use has been greatly improved.
    • Primitive types are now hyperlinked and documented.
  • Documentation has been moved from static.rust-lang.org/doc to doc.rust-lang.org
  • A new sandbox, play.rust-lang.org, is available for running and sharing rust code examples on-line.
  • Unused attributes are now more robustly warned about.
  • The dead_code lint now warns about unused struct fields.
  • Cross-compiling to iOS is now supported.
  • Cross-compiling to mipsel is now supported.
  • Stability attributes are now inherited by default and no longer apply to intra-crate usage, only inter-crate usage.
  • Error message related to non-exhaustive match expressions have been greatly improved.

Rust 0.10

• ~1500 changes, numerous bugfixes

• Language

  • A new RFC process is now in place for modifying the language.
  • Patterns with @-pointers have been removed from the language.
  • Patterns with unique vectors (~[T]) have been removed from the language.
  • Patterns with unique strings (~str) have been removed from the language.
  • @str has been removed from the language.
  • @[T] has been removed from the language.
  • @self has been removed from the language.
  • @Trait has been removed from the language.
  • Headers on ~ allocations which contain @ boxes inside the type for reference counting have been removed.
  • The semantics around the lifetimes of temporary expressions have changed, see #3511 and #11585 for more information.
  • Cross-crate syntax extensions are now possible, but feature gated. See #11151 for more information. This includes both macro_rules! macros as well as syntax extensions such as format!.
  • New lint modes have been added, and older ones have been turned on to be warn-by-default.
    • Unnecessary parentheses
    • Uppercase statics
    • Camel Case types
    • Uppercase variables
    • Publicly visible private types
    • #[deriving] with raw pointers
  • Unsafe functions can no longer be coerced to closures.
  • Various obscure macros such as log_syntax! are now behind feature gates.
  • The #[simd] attribute is now behind a feature gate.
  • Visibility is no longer allowed on extern crate statements, and unnecessary visibility (priv) is no longer allowed on use statements.
  • Trailing commas are now allowed in argument lists and tuple patterns.
  • The do keyword has been removed, it is now a reserved keyword.
  • Default type parameters have been implemented, but are feature gated.
  • Borrowed variables through captures in closures are now considered soundly.
  • extern mod is now extern crate
  • The Freeze trait has been removed.
  • The Share trait has been added for types that can be shared among threads.
  • Labels in macros are now hygienic.
  • Expression/statement macro invocations can be delimited with {} now.
  • Treatment of types allowed in static mut locations has been tweaked.
  • The * and . operators are now overloadable through the Deref and DerefMut traits.
  • ~Trait and proc no longer have Send bounds by default.
  • Partial type hints are now supported with the _ type marker.
  • An Unsafe type was introduced for interior mutability. It is now considered undefined to transmute from &T to &mut T without using the Unsafe type.
  • The #[linkage] attribute was implemented for extern statics/functions.
  • The inner attribute syntax has changed from #[foo]; to #![foo].
  • Pod was renamed to Copy.

• Libraries

  • The libextra library has been removed. It has now been decomposed into component libraries with smaller and more focused nuggets of functionality. The full list of libraries can be found on the documentation index page.
  • std: std::condition has been removed. All I/O errors are now propagated through the Result type. In order to assist with error handling, a try! macro for unwrapping errors with an early return and a lint for unused results has been added. See #12039 for more information.
  • std: The vec module has been renamed to slice.
  • std: A new vector type, Vec<T>, has been added in preparation for DST. This will become the only growable vector in the future.
  • std: std::io now has more public re-exports. Types such as BufferedReader are now found at std::io::BufferedReader instead of std::io::buffered::BufferedReader.
  • std: print and println are no longer in the prelude, the print! and println! macros are intended to be used instead.
  • std: Rc now has a Weak pointer for breaking cycles, and it no longer attempts to statically prevent cycles.
  • std: The standard distribution is adopting the policy of pushing failure to the user rather than failing in libraries. Many functions (such as slice::last()) now return Option<T> instead of T + failing.
  • std: fmt::Default has been renamed to fmt::Show, and it now has a new deriving mode: #[deriving(Show)].
  • std: ToStr is now implemented for all types implementing Show.
  • std: The formatting trait methods now take &self instead of &T
  • std: The invert() method on iterators has been renamed to rev()
  • std: std::num has seen a reduction in the genericity of its traits, consolidating functionality into a few core traits.
  • std: Backtraces are now printed on task failure if the environment variable RUST_BACKTRACE is present.
  • std: Naming conventions for iterators have been standardized. More details can be found on the wiki's style guide.
  • std: eof() has been removed from the Reader trait. Specific types may still implement the function.
  • std: Networking types are now cloneable to allow simultaneous reads/writes.
  • std: assert_approx_eq! has been removed
  • std: The e and E formatting specifiers for floats have been added to print them in exponential notation.
  • std: The Times trait has been removed
  • std: Indications of variance and opting out of builtin bounds is done through marker types in std::kinds::marker now
  • std: hash has been rewritten, IterBytes has been removed, and #[deriving(Hash)] is now possible.
  • std: SharedChan has been removed, Sender is now cloneable.
  • std: Chan and Port were renamed to Sender and Receiver.
  • std: Chan::new is now channel().
  • std: A new synchronous channel type has been implemented.
  • std: A select! macro is now provided for selecting over Receivers.
  • std: hashmap and trie have been moved to libcollections
  • std: run has been rolled into io::process
  • std: assert_eq! now uses {} instead of {:?}
  • std: The equality and comparison traits have seen some reorganization.
  • std: rand has moved to librand.
  • std: to_{lower,upper}case has been implemented for char.
  • std: Logging has been moved to liblog.
  • collections: HashMap has been rewritten for higher performance and less memory usage.
  • native: The default runtime is now libnative. If libgreen is desired, it can be booted manually. The runtime guide has more information and examples.
  • native: All I/O functionality except signals has been implemented.
  • green: Task spawning with libgreen has been optimized with stack caching and various trimming of code.
  • green: Tasks spawned by libgreen now have an unmapped guard page.
  • sync: The extra::sync module has been updated to modern rust (and moved to the sync library), tweaking and improving various interfaces while dropping redundant functionality.
  • sync: A new Barrier type has been added to the sync library.
  • sync: An efficient mutex for native and green tasks has been implemented.
  • serialize: The base64 module has seen some improvement. It treats newlines better, has non-string error values, and has seen general cleanup.
  • fourcc: A fourcc! macro was introduced
  • hexfloat: A hexfloat! macro was implemented for specifying floats via a hexadecimal literal.

• Tooling

  • rustpkg has been deprecated and removed from the main repository. Its replacement, cargo, is under development.
  • Nightly builds of rust are now available
  • The memory usage of rustc has been improved many times throughout this release cycle.
  • The build process supports disabling rpath support for the rustc binary itself.
  • Code generation has improved in some cases, giving more information to the LLVM optimization passes to enable more extensive optimizations.
  • Debuginfo compatibility with lldb on OSX has been restored.
  • The master branch is now gated on an android bot, making building for android much more reliable.
  • Output flags have been centralized into one --emit flag.
  • Crate type flags have been centralized into one --crate-type flag.
  • Codegen flags have been consolidated behind a -C flag.
  • Linking against outdated crates now has improved error messages.
  • Error messages with lifetimes will often suggest how to annotate the function to fix the error.
  • Many more types are documented in the standard library, and new guides were written.
  • Many rustdoc improvements:
    • code blocks are syntax highlighted.
    • render standalone markdown files.
    • the --test flag tests all code blocks by default.
    • exported macros are displayed.
    • re-exported types have their documentation inlined at the location of the first re-export.
    • search works across crates that have been rendered to the same output directory.

Rust 0.9

• ~1800 changes, numerous bugfixes

• Language

  • The float type has been removed. Use f32 or f64 instead.
  • A new facility for enabling experimental features (feature gating) has been added, using the crate-level #[feature(foo)] attribute.
  • Managed boxes (@) are now behind a feature gate (#[feature(managed_boxes)]) in preparation for future removal. Use the standard library's Gc or Rc types instead.
  • @mut has been removed. Use std::cell::{Cell, RefCell} instead.
  • Jumping back to the top of a loop is now done with continue instead of loop.
  • Strings can no longer be mutated through index assignment.
  • Raw strings can be created via the basic r"foo" syntax or with matched hash delimiters, as in r###"foo"###.
  • ~fn is now written proc (args) -> retval { ... } and may only be called once.
  • The &fn type is now written |args| -> ret to match the literal form.
  • @fns have been removed.
  • do only works with procs in order to make it obvious what the cost of do is.
  • Single-element tuple-like structs can no longer be dereferenced to obtain the inner value. A more comprehensive solution for overloading the dereference operator will be provided in the future.
  • The #[link(...)] attribute has been replaced with #[crate_id = "name#vers"].
  • Empty impls must be terminated with empty braces and may not be terminated with a semicolon.
  • Keywords are no longer allowed as lifetime names; the self lifetime no longer has any special meaning.
  • The old fmt! string formatting macro has been removed.
  • printf! and printfln! (old-style formatting) removed in favor of print! and println!.
  • mut works in patterns now, as in let (mut x, y) = (1, 2);.
  • The extern mod foo (name = "bar") syntax has been removed. Use extern mod foo = "bar" instead.
  • New reserved keywords: alignof, offsetof, sizeof.
  • Macros can have attributes.
  • Macros can expand to items with attributes.
  • Macros can expand to multiple items.
  • The asm! macro is feature-gated (#[feature(asm)]).
  • Comments may be nested.
  • Values automatically coerce to trait objects they implement, without an explicit as.
  • Enum discriminants are no longer an entire word but as small as needed to contain all the variants. The repr attribute can be used to override the discriminant size, as in #[repr(int)] for integer-sized, and #[repr(C)] to match C enums.
  • Non-string literals are not allowed in attributes (they never worked).
  • The FFI now supports variadic functions.
  • Octal numeric literals, as in 0o7777.
  • The concat! syntax extension performs compile-time string concatenation.
  • The #[fixed_stack_segment] and #[rust_stack] attributes have been removed as Rust no longer uses segmented stacks.
  • Non-ascii identifiers are feature-gated (#[feature(non_ascii_idents)]).
  • Ignoring all fields of an enum variant or tuple-struct is done with .., not *; ignoring remaining fields of a struct is also done with .., not _; ignoring a slice of a vector is done with .., not .._.
  • rustc supports the "win64" calling convention via extern "win64".
  • rustc supports the "system" calling convention, which defaults to the preferred convention for the target platform, "stdcall" on 32-bit Windows, "C" elsewhere.
  • The type_overflow lint (default: warn) checks literals for overflow.
  • The unsafe_block lint (default: allow) checks for usage of unsafe.
  • The attribute_usage lint (default: warn) warns about unknown attributes.
  • The unknown_features lint (default: warn) warns about unknown feature gates.
  • The dead_code lint (default: warn) checks for dead code.
  • Rust libraries can be linked statically to one another
  • #[link_args] is behind the link_args feature gate.
  • Native libraries are now linked with #[link(name = "foo")]
  • Native libraries can be statically linked to a rust crate (#[link(name = "foo", kind = "static")]).
  • Native OS X frameworks are now officially supported (#[link(name = "foo", kind = "framework")]).
  • The #[thread_local] attribute creates thread-local (not task-local) variables. Currently behind the thread_local feature gate.
  • The return keyword may be used in closures.
  • Types that can be copied via a memcpy implement the Pod kind.
  • The cfg attribute can now be used on struct fields and enum variants.

• Libraries

  • std: The option and result API's have been overhauled to make them simpler, more consistent, and more composable.
  • std: The entire std::io module has been replaced with one that is more comprehensive and that properly interfaces with the underlying scheduler. File, TCP, UDP, Unix sockets, pipes, and timers are all implemented.
  • std: io::util contains a number of useful implementations of Reader and Writer, including NullReader, NullWriter, ZeroReader, TeeReader.
  • std: The reference counted pointer type extra::rc moved into std.
  • std: The Gc type in the gc module will replace @ (it is currently just a wrapper around it).
  • std: The Either type has been removed.
  • std: fmt::Default can be implemented for any type to provide default formatting to the format! macro, as in format!("{}", myfoo).
  • std: The rand API continues to be tweaked.
  • std: The rust_begin_unwind function, useful for inserting breakpoints on failure in gdb, is now named rust_fail.
  • std: The each_key and each_value methods on HashMap have been replaced by the keys and values iterators.
  • std: Functions dealing with type size and alignment have moved from the sys module to the mem module.
  • std: The path module was written and API changed.
  • std: str::from_utf8 has been changed to cast instead of allocate.
  • std: starts_with and ends_with methods added to vectors via the ImmutableEqVector trait, which is in the prelude.
  • std: Vectors can be indexed with the get_opt method, which returns None if the index is out of bounds.
  • std: Task failure no longer propagates between tasks, as the model was complex, expensive, and incompatible with thread-based tasks.
  • std: The Any type can be used for dynamic typing.
  • std: ~Any can be passed to the fail! macro and retrieved via task::try.
  • std: Methods that produce iterators generally do not have an _iter suffix now.
  • std: cell::Cell and cell::RefCell can be used to introduce mutability roots (mutable fields, etc.). Use instead of e.g. @mut.
  • std: util::ignore renamed to prelude::drop.
  • std: Slices have sort and sort_by methods via the MutableVector trait.
  • std: vec::raw has seen a lot of cleanup and API changes.
  • std: The standard library no longer includes any C++ code, and very minimal C, eliminating the dependency on libstdc++.
  • std: Runtime scheduling and I/O functionality has been factored out into extensible interfaces and is now implemented by two different crates: libnative, for native threading and I/O; and libgreen, for green threading and I/O. This paves the way for using the standard library in more limited embedded environments.
  • std: The comm module has been rewritten to be much faster, have a simpler, more consistent API, and to work for both native and green threading.
  • std: All libuv dependencies have been moved into the rustuv crate.
  • native: New implementations of runtime scheduling on top of OS threads.
  • native: New native implementations of TCP, UDP, file I/O, process spawning, and other I/O.
  • green: The green thread scheduler and message passing types are almost entirely lock-free.
  • extra: The flatpipes module had bitrotted and was removed.
  • extra: All crypto functions have been removed and Rust now has a policy of not reimplementing crypto in the standard library. In the future crypto will be provided by external crates with bindings to established libraries.
  • extra: c_vec has been modernized.
  • extra: The sort module has been removed. Use the sort method on mutable slices.

• Tooling

  • The rust and rusti commands have been removed, due to lack of maintenance.
  • rustdoc was completely rewritten.
  • rustdoc can test code examples in documentation.
  • rustpkg can test packages with the argument, 'test'.
  • rustpkg supports arbitrary dependencies, including C libraries.
  • rustc's support for generating debug info is improved again.
  • rustc has better error reporting for unbalanced delimiters.
  • rustc's JIT support was removed due to bitrot.
  • Executables and static libraries can be built with LTO (-Z lto)
  • rustc adds a --dep-info flag for communicating dependencies to build tools.

Rust 0.8

• ~2200 changes, numerous bugfixes

• Language

  • The for loop syntax has changed to work with the Iterator trait.
  • At long last, unwinding works on Windows.
  • Default methods are ready for use.
  • Many trait inheritance bugs fixed.
  • Owned and borrowed trait objects work more reliably.
  • copy is no longer a keyword. It has been replaced by the Clone trait.
  • rustc can omit emission of code for the debug! macro if it is passed --cfg ndebug
  • mod.rs is now "blessed". When loading mod foo;, rustc will now look for foo.rs, then foo/mod.rs, and will generate an error when both are present.
  • Strings no longer contain trailing nulls. The new std::c_str module provides new mechanisms for converting to C strings.
  • The type of foreign functions is now extern "C" fn instead of `*u8'.
  • The FFI has been overhauled such that foreign functions are called directly, instead of through a stack-switching wrapper.
  • Calling a foreign function must be done through a Rust function with the #[fixed_stack_segment] attribute.
  • The externfn! macro can be used to declare both a foreign function and a #[fixed_stack_segment] wrapper at once.
  • pub and priv modifiers on extern blocks are no longer parsed.
  • unsafe is no longer allowed on extern fns - they are all unsafe.
  • priv is disallowed everywhere except for struct fields and enum variants.
  • &T (besides &'static T) is no longer allowed in @T.
  • ref bindings in irrefutable patterns work correctly now.
  • char is now prevented from containing invalid code points.
  • Casting to bool is no longer allowed.
  • \0 is now accepted as an escape in chars and strings.
  • yield is a reserved keyword.
  • typeof is a reserved keyword.
  • Crates may be imported by URL with extern mod foo = "url";.
  • Explicit enum discriminants may be given as uints as in enum E { V = 0u }
  • Static vectors can be initialized with repeating elements, e.g. static foo: [u8, .. 100]: [0, .. 100];.
  • Static structs can be initialized with functional record update, e.g. static foo: Foo = Foo { a: 5, .. bar };.
  • cfg! can be used to conditionally execute code based on the crate configuration, similarly to #[cfg(...)].
  • The unnecessary_qualification lint detects unneeded module prefixes (default: allow).
  • Arithmetic operations have been implemented on the SIMD types in std::unstable::simd.
  • Exchange allocation headers were removed, reducing memory usage.
  • format! implements a completely new, extensible, and higher-performance string formatting system. It will replace fmt!.
  • print! and println! write formatted strings (using the format! extension) to stdout.
  • write! and writeln! write formatted strings (using the format! extension) to the new Writers in std::rt::io.
  • The library section in which a function or static is placed may be specified with #[link_section = "..."].
  • The proto! syntax extension for defining bounded message protocols was removed.
  • macro_rules! is hygienic for let declarations.
  • The #[export_name] attribute specifies the name of a symbol.
  • unreachable! can be used to indicate unreachable code, and fails if executed.

• Libraries

  • std: Transitioned to the new runtime, written in Rust.
  • std: Added an experimental I/O library, rt::io, based on the new runtime.
  • std: A new generic range function was added to the prelude, replacing uint::range and friends.
  • std: range_rev no longer exists. Since range is an iterator it can be reversed with range(lo, hi).invert().
  • std: The chain method on option renamed to and_then; unwrap_or_default renamed to unwrap_or.
  • std: The iterator module was renamed to iter.
  • std: Integral types now support the checked_add, checked_sub, and checked_mul operations for detecting overflow.
  • std: Many methods in str, vec, option, result` were renamed for consistency.
  • std: Methods are standardizing on conventions for casting methods: to_foo for copying, into_foo for moving, as_foo for temporary and cheap casts.
  • std: The CString type in c_str provides new ways to convert to and from C strings.
  • std: DoubleEndedIterator can yield elements in two directions.
  • std: The mut_split method on vectors partitions an &mut [T] into two splices.
  • std: str::from_bytes renamed to str::from_utf8.
  • std: pop_opt and shift_opt methods added to vectors.
  • std: The task-local data interface no longer uses @, and keys are no longer function pointers.
  • std: The swap_unwrap method of Option renamed to take_unwrap.
  • std: Added SharedPort to comm.
  • std: Eq has a default method for ne; only eq is required in implementations.
  • std: Ord has default methods for le, gt and ge; only lt is required in implementations.
  • std: is_utf8 performance is improved, impacting many string functions.
  • std: os::MemoryMap provides cross-platform mmap.
  • std: ptr::offset is now unsafe, but also more optimized. Offsets that are not 'in-bounds' are considered undefined.
  • std: Many freestanding functions in vec removed in favor of methods.
  • std: Many freestanding functions on scalar types removed in favor of methods.
  • std: Many options to task builders were removed since they don't make sense in the new scheduler design.
  • std: More containers implement FromIterator so can be created by the collect method.
  • std: More complete atomic types in unstable::atomics.
  • std: comm::PortSet removed.
  • std: Mutating methods in the Set and Map traits have been moved into the MutableSet and MutableMap traits. Container::is_empty, Map::contains_key, MutableMap::insert, and MutableMap::remove have default implementations.
  • std: Various from_str functions were removed in favor of a generic from_str which is available in the prelude.
  • std: util::unreachable removed in favor of the unreachable! macro.
  • extra: dlist, the doubly-linked list was modernized.
  • extra: Added a hex module with ToHex and FromHex traits.
  • extra: Added glob module, replacing std::os::glob.
  • extra: rope was removed.
  • extra: deque was renamed to ringbuf. RingBuf implements Deque.
  • extra: net, and timer were removed. The experimental replacements are std::rt::io::net and std::rt::io::timer.
  • extra: Iterators implemented for SmallIntMap.
  • extra: Iterators implemented for Bitv and BitvSet.
  • extra: SmallIntSet removed. Use BitvSet.
  • extra: Performance of JSON parsing greatly improved.
  • extra: semver updated to SemVer 2.0.0.
  • extra: term handles more terminals correctly.
  • extra: dbg module removed.
  • extra: par module removed.
  • extra: future was cleaned up, with some method renames.
  • extra: Most free functions in getopts were converted to methods.

• Other

  • rustc's debug info generation (-Z debug-info) is greatly improved.
  • rustc accepts --target-cpu to compile to a specific CPU architecture, similarly to gcc's --march flag.
  • rustc's performance compiling small crates is much better.
  • rustpkg has received many improvements.
  • rustpkg supports git tags as package IDs.
  • rustpkg builds into target-specific directories so it can be used for cross-compiling.
  • The number of concurrent test tasks is controlled by the environment variable RUST_TEST_TASKS.
  • The test harness can now report metrics for benchmarks.
  • All tools have man pages.
  • Programs compiled with --test now support the -h and --help flags.
  • The runtime uses jemalloc for allocations.
  • Segmented stacks are temporarily disabled as part of the transition to the new runtime. Stack overflows are possible!
  • A new documentation backend, rustdoc_ng, is available for use. It is still invoked through the normal rustdoc command.

Rust 0.7

• ~2000 changes, numerous bugfixes

• Language

  • impls no longer accept a visibility qualifier. Put them on methods instead.
  • The borrow checker has been rewritten with flow-sensitivity, fixing many bugs and inconveniences.
  • The self parameter no longer implicitly means &'self self, and can be explicitly marked with a lifetime.
  • Overloadable compound operators (+=, etc.) have been temporarily removed due to bugs.
  • The for loop protocol now requires for-iterators to return bool so they compose better.
  • The Durable trait is replaced with the 'static bounds.
  • Trait default methods work more often.
  • Structs with the #[packed] attribute have byte alignment and no padding between fields.
  • Type parameters bound by Copy must now be copied explicitly with the copy keyword.
  • It is now illegal to move out of a dereferenced unsafe pointer.
  • Option<~T> is now represented as a nullable pointer.
  • @mut does dynamic borrow checks correctly.
  • The main function is only detected at the topmost level of the crate. The #[main] attribute is still valid anywhere.
  • Struct fields may no longer be mutable. Use inherited mutability.
  • The #[no_send] attribute makes a type that would otherwise be Send, not.
  • The #[no_freeze] attribute makes a type that would otherwise be Freeze, not.
  • Unbounded recursion will abort the process after reaching the limit specified by the RUST_MAX_STACK environment variable (default: 1GB).
  • The vecs_implicitly_copyable lint mode has been removed. Vectors are never implicitly copyable.
  • #[static_assert] makes compile-time assertions about static bools.
  • At long last, 'argument modes' no longer exist.
  • The rarely used use mod statement no longer exists.

• Syntax extensions

  • fail! and assert! accept ~str, &'static str or fmt!-style argument list.
  • Encodable, Decodable, Ord, TotalOrd, TotalEq, DeepClone, Rand, Zero and ToStr can all be automatically derived with #[deriving(...)].
  • The bytes! macro returns a vector of bytes for string, u8, char, and unsuffixed integer literals.

• Libraries

  • The core crate was renamed to std.
  • The std crate was renamed to extra.
  • More and improved documentation.
  • std: iterator module for external iterator objects.
  • Many old-style (internal, higher-order function) iterators replaced by implementations of Iterator.
  • std: Many old internal vector and string iterators, incl. any, all. removed.
  • std: The finalize method of Drop renamed to drop.
  • std: The drop method now takes &mut self instead of &self.
  • std: The prelude no longer re-exports any modules, only types and traits.
  • std: Prelude additions: print, println, FromStr, ApproxEq, Equiv, Iterator, IteratorUtil, many numeric traits, many tuple traits.
  • std: New numeric traits: Fractional, Real, RealExt, Integer, Ratio, Algebraic, Trigonometric, Exponential, Primitive.
  • std: Tuple traits and accessors defined for up to 12-tuples, e.g. (0, 1, 2).n2() or (0, 1, 2).n2_ref().
  • std: Many types implement Clone.
  • std: path type renamed to Path.
  • std: mut module and Mut type removed.
  • std: Many standalone functions removed in favor of methods and iterators in vec, str. In the future methods will also work as functions.
  • std: reinterpret_cast removed. Use transmute.
  • std: ascii string handling in std::ascii.
  • std: Rand is implemented for ~/@.
  • std: run module for spawning processes overhauled.
  • std: Various atomic types added to unstable::atomic.
  • std: Various types implement Zero.
  • std: LinearMap and LinearSet renamed to HashMap and HashSet.
  • std: Borrowed pointer functions moved from ptr to borrow.
  • std: Added os::mkdir_recursive.
  • std: Added os::glob function performs filesystems globs.
  • std: FuzzyEq renamed to ApproxEq.
  • std: Map now defines pop and swap methods.
  • std: Cell constructors converted to static methods.
  • extra: rc module adds the reference counted pointers, Rc and RcMut.
  • extra: flate module moved from std to extra.
  • extra: fileinput module for iterating over a series of files.
  • extra: Complex number type and complex module.
  • extra: Rational number type and rational module.
  • extra: BigInt, BigUint implement numeric and comparison traits.
  • extra: term uses terminfo now, is more correct.
  • extra: arc functions converted to methods.
  • extra: Implementation of fixed output size variations of SHA-2.

• Tooling

  • unused_variables lint mode for unused variables (default: warn).
  • unused_unsafe lint mode for detecting unnecessary unsafe blocks (default: warn).
  • unused_mut lint mode for identifying unused mut qualifiers (default: warn).
  • dead_assignment lint mode for unread variables (default: warn).
  • unnecessary_allocation lint mode detects some heap allocations that are immediately borrowed so could be written without allocating (default: warn).
  • missing_doc lint mode (default: allow).
  • unreachable_code lint mode (default: warn).
  • The rusti command has been rewritten and a number of bugs addressed.
  • rustc outputs in color on more terminals.
  • rustc accepts a --link-args flag to pass arguments to the linker.
  • rustc accepts a -Z print-link-args flag for debugging linkage.
  • Compiling with -g will make the binary record information about dynamic borrowcheck failures for debugging.
  • rustdoc has a nicer stylesheet.
  • Various improvements to rustdoc.
  • Improvements to rustpkg (see the detailed release notes).

Rust 0.6

• ~2100 changes, numerous bugfixes

• Syntax changes

  • The self type parameter in traits is now spelled Self
  • The self parameter in trait and impl methods must now be explicitly named (for example: fn f(&self) { }). Implicit self is deprecated.
  • Static methods no longer require the static keyword and instead are distinguished by the lack of a self parameter
  • Replaced the Durable trait with the 'static lifetime
  • The old closure type syntax with the trailing sigil has been removed in favor of the more consistent leading sigil
  • super is a keyword, and may be prefixed to paths
  • Trait bounds are separated with + instead of whitespace
  • Traits are implemented with impl Trait for Type instead of impl Type: Trait
  • Lifetime syntax is now &'l foo instead of &l/foo
  • The export keyword has finally been removed
  • The move keyword has been removed (see "Semantic changes")
  • The interior mutability qualifier on vectors, [mut T], has been removed. Use &mut [T], etc.
  • mut is no longer valid in ~mut T. Use inherited mutability
  • fail is no longer a keyword. Use fail!()
  • assert is no longer a keyword. Use assert!()
  • log is no longer a keyword. use debug!, etc.
  • 1-tuples may be represented as (T,)
  • Struct fields may no longer be mut. Use inherited mutability, @mut T, core::mut or core::cell
  • extern mod { ... } is no longer valid syntax for foreign function modules. Use extern blocks: extern { ... }
  • Newtype enums removed. Use tuple-structs.
  • Trait implementations no longer support visibility modifiers
  • Pattern matching over vectors improved and expanded
  • const renamed to static to correspond to lifetime name, and make room for future static mut unsafe mutable globals.
  • Replaced #[deriving_eq] with #[deriving(Eq)], etc.
  • Clone implementations can be automatically generated with #[deriving(Clone)]
  • Casts to traits must use a pointer sigil, e.g. @foo as @Bar instead of foo as Bar.
  • Fixed length vector types are now written as [int, .. 3] instead of [int * 3].
  • Fixed length vector types can express the length as a constant expression. (ex: [int, .. GL_BUFFER_SIZE - 2])

• Semantic changes

  • Types with owned pointers or custom destructors move by default, eliminating the move keyword
  • All foreign functions are considered unsafe
  • &mut is now unaliasable
  • Writes to borrowed @mut pointers are prevented dynamically
  • () has size 0
  • The name of the main function can be customized using #[main]
  • The default type of an inferred closure is &fn instead of @fn
  • use statements may no longer be "chained" - they cannot import identifiers imported by previous use statements
  • use statements are crate relative, importing from the "top" of the crate by default. Paths may be prefixed with super:: or self:: to change the search behavior.
  • Method visibility is inherited from the implementation declaration
  • Structural records have been removed
  • Many more types can be used in static items, including enums 'static-lifetime pointers and vectors
  • Pattern matching over vectors improved and expanded
  • Typechecking of closure types has been overhauled to improve inference and eliminate unsoundness
  • Macros leave scope at the end of modules, unless that module is tagged with #[macro_escape]

• Libraries

  • Added big integers to std::bigint
  • Removed core::oldcomm module
  • Added pipe-based core::comm module
  • Numeric traits have been reorganized under core::num
  • vec::slice finally returns a slice
  • debug! and friends don't require a format string, e.g. debug!(Foo)
  • Containers reorganized around traits in core::container
  • core::dvec removed, ~[T] is a drop-in replacement
  • core::send_map renamed to core::hashmap
  • std::map removed; replaced with core::hashmap
  • std::treemap reimplemented as an owned balanced tree
  • std::deque and std::smallintmap reimplemented as owned containers
  • core::trie added as a fast ordered map for integer keys
  • Set types added to core::hashmap, core::trie and std::treemap
  • Ord split into Ord and TotalOrd. Ord is still used to overload the comparison operators, whereas TotalOrd is used by certain container types

• Other

  • Replaced the 'cargo' package manager with 'rustpkg'
  • Added all-purpose 'rust' tool
  • rustc --test now supports benchmarks with the #[bench] attribute
  • rustc now attempts to offer spelling suggestions
  • Improved support for ARM and Android
  • Preliminary MIPS backend
  • Improved foreign function ABI implementation for x86, x86_64
  • Various memory usage improvements
  • Rust code may be embedded in foreign code under limited circumstances
  • Inline assembler supported by new asm!() syntax extension.

Rust 0.5

• ~900 changes, numerous bugfixes

• Syntax changes

  • Removed <- move operator
  • Completed the transition from the #fmt extension syntax to fmt!
  • Removed old fixed length vector syntax - [T]/N
  • New token-based quasi-quoters, quote_tokens!, quote_expr!, etc.
  • Macros may now expand to items and statements
  • a.b() is always parsed as a method call, never as a field projection
  • Eq and IterBytes implementations can be automatically generated with #[deriving_eq] and #[deriving_iter_bytes] respectively
  • Removed the special crate language for .rc files
  • Function arguments may consist of any irrefutable pattern

• Semantic changes

  • & and ~ pointers may point to objects
  • Tuple structs - struct Foo(Bar, Baz). Will replace newtype enums.
  • Enum variants may be structs
  • Destructors can be added to all nominal types with the Drop trait
  • Structs and nullary enum variants may be constants
  • Values that cannot be implicitly copied are now automatically moved without writing move explicitly
  • &T may now be coerced to *T
  • Coercions happen in let statements as well as function calls
  • use statements now take crate-relative paths
  • The module and type namespaces have been merged so that static method names can be resolved under the trait in which they are declared

• Improved support for language features

  • Trait inheritance works in many scenarios
  • More support for explicit self arguments in methods - self, &self @self, and ~self all generally work as expected
  • Static methods work in more situations
  • Experimental: Traits may declare default methods for the implementations to use

• Libraries

  • New condition handling system in core::condition
  • Timsort added to std::sort
  • New priority queue, std::priority_queue
  • Pipes for serializable types, `std::flatpipes'
  • Serialization overhauled to be trait-based
  • Expanded getopts definitions
  • Moved futures to std
  • More functions are pure now
  • core::comm renamed to oldcomm. Still deprecated
  • rustdoc and cargo are libraries now

• Misc

  • Added a preliminary REPL, rusti
  • License changed from MIT to dual MIT/APL2

Rust 0.4

• ~2000 changes, numerous bugfixes

• Syntax

  • All keywords are now strict and may not be used as identifiers anywhere
  • Keyword removal: 'again', 'import', 'check', 'new', 'owned', 'send', 'of', 'with', 'to', 'class'.
  • Classes are replaced with simpler structs
  • Explicit method self types
  • ret became return and alt became match
  • import is now use; use is now extern mod`
  • extern mod { ... } is now extern { ... }
  • use mod is the recommended way to import modules
  • pub and priv replace deprecated export lists
  • The syntax of match pattern arms now uses fat arrow (=>)
  • main no longer accepts an args vector; use os::args instead

• Semantics

  • Trait implementations are now coherent, ala Haskell typeclasses
  • Trait methods may be static
  • Argument modes are deprecated
  • Borrowed pointers are much more mature and recommended for use
  • Strings and vectors in the static region are stored in constant memory
  • Typestate was removed
  • Resolution rewritten to be more reliable
  • Support for 'dual-mode' data structures (freezing and thawing)

• Libraries

  • Most binary operators can now be overloaded via the traits in `core::ops'
  • std::net::url for representing URLs
  • Sendable hash maps in core::send_map
  • `core::task' gained a (currently unsafe) task-local storage API

• Concurrency

  • An efficient new intertask communication primitive called the pipe, along with a number of higher-level channel types, in core::pipes
  • std::arc, an atomically reference counted, immutable, shared memory type
  • std::sync, various exotic synchronization tools based on arcs and pipes
  • Futures are now based on pipes and sendable
  • More robust linked task failure
  • Improved task builder API

• Other

  • Improved error reporting
  • Preliminary JIT support
  • Preliminary work on precise GC
  • Extensive architectural improvements to rustc
  • Begun a transition away from buggy C++-based reflection (shape) code to Rust-based (visitor) code
  • All hash functions and tables converted to secure, randomized SipHash

Rust 0.3

• ~1900 changes, numerous bugfixes

• New coding conveniences

  • Integer-literal suffix inference
  • Per-item control over warnings, errors
  • #[cfg(windows)] and #[cfg(unix)] attributes
  • Documentation comments
  • More compact closure syntax
  • 'do' expressions for treating higher-order functions as control structures
  • *-patterns (wildcard extended to all constructor fields)

• Semantic cleanup

  • Name resolution pass and exhaustiveness checker rewritten
  • Region pointers and borrow checking supersede alias analysis
  • Init-ness checking is now provided by a region-based liveness pass instead of the typestate pass; same for last-use analysis
  • Extensive work on region pointers

• Experimental new language features

  • Slices and fixed-size, interior-allocated vectors
  • #!-comments for lang versioning, shell execution
  • Destructors and iface implementation for classes; type-parameterized classes and class methods
  • 'const' type kind for types that can be used to implement shared-memory concurrency patterns

• Type reflection

• Removal of various obsolete features

  • Keywords: 'be', 'prove', 'syntax', 'note', 'mutable', 'bind', 'crust', 'native' (now 'extern'), 'cont' (now 'again')

  • Constructs: do-while loops ('do' repurposed), fn binding, resources (replaced by destructors)

• Compiler reorganization

  • Syntax-layer of compiler split into separate crate
  • Clang (from LLVM project) integrated into build
  • Typechecker split into sub-modules

• New library code

  • New time functions
  • Extension methods for many built-in types
  • Arc: atomic-refcount read-only / exclusive-use shared cells
  • Par: parallel map and search routines
  • Extensive work on libuv interface
  • Much vector code moved to libraries
  • Syntax extensions: #line, #col, #file, #mod, #stringify, #include, #include_str, #include_bin

• Tool improvements

  • Cargo automatically resolves dependencies