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 It has been replaced by the Clone trait.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

Rust 0.2

• 1500 changes, numerous bugfixes

• New docs and doc tooling

• New port: FreeBSD x86_64

• Compilation model enhancements

  • Generics now specialized, multiply instantiated
  • Functions now inlined across separate crates

• Scheduling, stack and threading fixes

  • Noticeably improved message-passing performance
  • Explicit schedulers
  • Callbacks from C
  • Helgrind clean

• Experimental new language features

  • Operator overloading
  • Region pointers
  • Classes

• Various language extensions

  • C-callback function types: 'crust fn ...'
  • Infinite-loop construct: 'loop { ... }'
  • Shorten 'mutable' to 'mut'
  • Required mutable-local qualifier: 'let mut ...'
  • Basic glob-exporting: 'export foo::*;'
  • Alt now exhaustive, 'alt check' for runtime-checked
  • Block-function form of 'for' loop, with 'break' and 'ret'.

• New library code

  • AST quasi-quote syntax extension
  • Revived libuv interface
  • New modules: core::{future, iter}, std::arena
  • Merged per-platform std::{os*, fs*} to core::{libc, os}
  • Extensive cleanup, regularization in libstd, libcore

Rust 0.1

• Most language features work, including:

  • Unique pointers, unique closures, move semantics
  • Interface-constrained generics
  • Static interface dispatch
  • Stack growth
  • Multithread task scheduling
  • Typestate predicates
  • Failure unwinding, destructors
  • Pattern matching and destructuring assignment
  • Lightweight block-lambda syntax
  • Preliminary macro-by-example

• Compiler works with the following configurations:

  • Linux: x86 and x86_64 hosts and targets
  • macOS: x86 and x86_64 hosts and targets
  • Windows: x86 hosts and targets

• Cross compilation / multi-target configuration supported.

• Preliminary API-documentation and package-management tools included.

Known issues:

• Documentation is incomplete.

• Performance is below intended target.

• Standard library APIs are subject to extensive change, reorganization.

• Language-level versioning is not yet operational - future code will break unexpectedly.