- ~900 changes, numerous bugfixes
- The new object lifetime defaults have been turned
on after a cycle of warnings about the change. Now types
like
&'a Box<Trait>
(or&'a Rc<Trait>
, etc) will change from being interpreted as&'a Box<Trait+'a>
to&'a Box<Trait+'static>
. - The Rustonomicon is a new book in the official documentation that dives into writing unsafe Rust.
- The
Duration
API, has been stabilized. This basic unit of timekeeping is employed by other std APIs, as well as out-of-tree time crates.
- The new object lifetime defaults have been turned on after a cycle of warnings about the change.
- There is a known regression in how object lifetime elision is interpreted, the proper solution for which is undetermined.
- The
#[prelude_import]
attribute, an internal implementation detail, was accidentally stabilized previously. It has been put behind theprelude_import
feature gate. This change is believed to break no existing code. - The behavior of
size_of_val
andalign_of_val
is more sane for dynamically sized types. Code that relied on the previous behavior is thought to be broken. - The
dropck
rules, which checks that destructors can't access destroyed values, have been updated to match the RFC. This fixes some soundness holes, and as such will cause some previously-compiling code to no longer build.
- The new object lifetime defaults have been turned on after a cycle of warnings about the change.
- Semicolons may now follow types and paths in macros.
- The behavior of
size_of_val
andalign_of_val
is more sane for dynamically sized types. Code that relied on the previous behavior is not known to exist, and suspected to be broken. 'static
variables may now be recursive.ref
bindings choose betweenDeref
andDerefMut
implementations correctly.- The
dropck
rules, which checks that destructors can't access destroyed values, have been updated to match the RFC.
- The
Duration
API, has been stabilized, as well as thestd::time
module, which presently contains onlyDuration
. Box<str>
andBox<[T]>
both implementClone
.- The owned C string,
CString
, implementsBorrow
and the borrowed C string,CStr
, implementsToOwned
. The two of these allow C strings to be borrowed and cloned in generic code. CStr
implementsDebug
.AtomicPtr
implementsDebug
.Error
trait objects can be downcast to their concrete types in many common configurations, using theis
,downcast
,downcast_ref
anddowncast_mut
methods, similarly to theAny
trait.- Searching for substrings now employs the two-way algorithm
instead of doing a naive search. This gives major speedups to a
number of methods, including
contains
,find
,rfind
,split
.starts_with
andends_with
are also faster. - The performance of
PartialEq
for slices is much faster. - The
Hash
trait offers the default method,hash_slice
, which is overridden and optimized by the implementations for scalars. - The
Hasher
trait now has a number of specializedwrite_*
methods for primitive types, for efficiency. - The I/O-specific error type,
std::io::Error
, gained a set of methods for accessing the 'inner error', if any:get_ref
,get_mut
,into_inner
. As well, the implementation ofstd::error::Error::cause
also delegates to the inner error. process::Child
gained theid
method, which returns au32
representing the platform-specific process identifier.- The
connect
method on slices is deprecated, replaced by the newjoin
method (note that both of these are on the unstableSliceConcatExt
trait, but through the magic of the prelude are available to stable code anyway). - The
Div
operator is implemented forWrapping
types. DerefMut
is implemented forString
.- Performance of SipHash (the default hasher for
HashMap
) is better for long data. AtomicPtr
implementsSend
.- The
read_to_end
implementations forStdin
andFile
are now specialized to use uninitalized buffers for increased performance. - Lifetime parameters of foreign functions are now resolved properly.
- Rust can now, with some coercion, produce programs that run on Windows XP, though XP is not considered a supported platform.
- Porting Rust on Windows from the GNU toolchain to MSVC continues (1, 2, 3, 4). It is still not recommended for use in 1.3, though should be fully-functional in the 64-bit 1.4 beta.
- On Fedora-based systems installation will properly configure the dynamic linker.
- The compiler gained many new extended error descriptions, which can
be accessed with the
--explain
flag. - The
dropck
pass, which checks that destructors can't access destroyed values, has been rewritten. This fixes some soundness holes, and as such will cause some previously-compiling code to no longer build. rustc
now uses LLVM to write archive files where possible. Eventually this will eliminate the compiler's dependency on the ar utility.- Rust has preliminary support for i686 FreeBSD (it has long supported FreeBSD on x86_64).
- The
unused_mut
,unconditional_recursion
,improper_ctypes
, andnegate_unsigned
lints are more strict. - If landing pads are disabled (with
-Z no-landing-pads
),panic!
will kill the process instead of leaking.
- ~1200 changes, numerous bugfixes
- Dynamically-sized-type coercions allow smart pointer types
like
Rc
to contain types without a fixed size, arrays and trait objects, finally enabling use ofRc<[T]>
and completing the implementation of DST. - Parallel codegen is now working again, which can
substantially speed up large builds in debug mode; It also gets
another ~33% speedup when bootstrapping on a 4 core machine (using 8
jobs). It's not enabled by default, but will be "in the near
future". It can be activated with the
-C codegen-units=N
flag torustc
. - This is the first release with experimental support for linking with the MSVC linker and lib C on Windows (instead of using the GNU variants via MinGW). It is yet recommended only for the most intrepid Rusticians.
- Benchmark compilations are showing a 30% improvement in bootstrapping over 1.1.
- The
to_uppercase
andto_lowercase
methods onchar
now do unicode case mapping, which is a previously-planned change in behavior and considered a bugfix. mem::align_of
now specifies the minimum alignment for T, which is usually the alignment programs are interested in, and the same value reported by clang'salignof
.mem::min_align_of
is deprecated. This is not known to break real code.- The
#[packed]
attribute is no longer silently accepted by the compiler. This attribute did nothing and code that mentioned it likely did not work as intended. - Associated type defaults are now behind the
associated_type_defaults
feature gate. In 1.1 associated type defaults did not work, but could be mentioned syntactically. As such this breakage has minimal impact.
- Patterns with
ref mut
now correctly invokeDerefMut
when matching against dereferencable values.
- The
Extend
trait, which grows a collection from an iterator, is implemented over iterators of references, forString
,Vec
,LinkedList
,VecDeque
,EnumSet
,BinaryHeap
,VecMap
,BTreeSet
andBTreeMap
. RFC. - The
iter::once
function returns an iterator that yields a single element, anditer::empty
returns an iterator that yields no elements. - The
matches
andrmatches
methods onstr
return iterators over substring matches. Cell
andRefCell
both implementEq
.- A number of methods for wrapping arithmetic are added to the
integral types,
wrapping_div
,wrapping_rem
,wrapping_neg
,wrapping_shl
,wrapping_shr
. These are in addition to the existingwrapping_add
,wrapping_sub
, andwrapping_mul
methods, and alternatives to theWrapping
type.. It is illegal for the default arithmetic operations in Rust to overflow; the desire to wrap must be explicit. - The
{:#?}
formatting specifier displays the alternate, pretty-printed form of theDebug
formatter. This feature was actually introduced prior to 1.0 with little fanfare. fmt::Formatter
implementsfmt::Write
, afmt
-specific trait for writing data to formatted strings, similar toio::Write
.fmt::Formatter
adds 'debug builder' methods,debug_struct
,debug_tuple
,debug_list
,debug_set
,debug_map
. These are used by code generators to emit implementations ofDebug
.str
has newto_uppercase
andto_lowercase
methods that convert case, following Unicode case mapping.- It is now easier to handle poisoned locks. The
PoisonError
type, returned by failing lock operations, exposesinto_inner
,get_ref
, andget_mut
, which all give access to the inner lock guard, and allow the poisoned lock to continue to operate. Theis_poisoned
method ofRwLock
andMutex
can poll for a poisoned lock without attempting to take the lock. - On Unix the
FromRawFd
trait is implemented forStdio
, andAsRawFd
forChildStdin
,ChildStdout
,ChildStderr
. On Windows theFromRawHandle
trait is implemented forStdio
, andAsRawHandle
forChildStdin
,ChildStdout
,ChildStderr
. io::ErrorKind
has a new variant,InvalidData
, which indicates malformed input.
rustc
employs smarter heuristics for guessing at typos.rustc
emits more efficient code for no-op conversions between unsafe pointers.- Fat pointers are now passed in pairs of immediate arguments, resulting in faster compile times and smaller code.
- ~850 changes, numerous bugfixes
- The
std::fs
module has been expanded to expand the set of functionality exposed:DirEntry
now supports optimizations likefile_type
andmetadata
which don't incur a syscall on some platforms.- A
symlink_metadata
function has been added. - The
fs::Metadata
structure now lowers to its OS counterpart, providing access to all underlying information.
- The compiler now contains extended explanations of many errors. When an error
with an explanation occurs the compiler suggests using the
--explain
flag to read the explanation. Error explanations are also available online. - Thanks to multiple improvements to type checking, as well as other work, the time to bootstrap the compiler decreased by 32%.
- The
str::split_whitespace
method splits a string on unicode whitespace boundaries. - On both Windows and Unix, new extension traits provide conversion of
I/O types to and from the underlying system handles. On Unix, these
traits are
FromRawFd
andAsRawFd
, on WindowsFromRawHandle
andAsRawHandle
. These are implemented forFile
,TcpStream
,TcpListener
, andUpdSocket
. Further implementations forstd::process
will be stabilized later. - On Unix,
std::os::unix::symlink
creates symlinks. On Windows, symlinks can be created withstd::os::windows::symlink_dir
andstd::os::windows::symlink_file
. - The
mpsc::Receiver
type can now be converted into an iterator withinto_iter
on theIntoIterator
trait. Ipv4Addr
can be created fromu32
with theFrom<u32>
implementation of theFrom
trait.- The
Debug
implementation forRangeFull
creates output that is more consistent with other implementations. Debug
is implemented forFile
.- The
Default
implementation forArc
no longer requiresSync + Send
. - The
Iterator
methodscount
,nth
, andlast
have been overridden for slices to have O(1) performance instead of O(n). - Incorrect handling of paths on Windows has been improved in both the compiler and the standard library.
AtomicPtr
gained aDefault
implementation.- In accordance with Rust's policy on arithmetic overflow
abs
now panics on overflow when debug assertions are enabled. - The
Cloned
iterator, which was accidentally left unstable for 1.0 has been stabilized. - The
Incoming
iterator, which iterates over incoming TCP connections, and which was accidentally unnamable in 1.0, is now properly exported. BinaryHeap
no longer corrupts itself when functions called bysift_up
orsift_down
panic.- The
split_off
method ofLinkedList
no longer corrupts the list in certain scenarios.
- Type checking performance has improved notably with multiple improvements.
- The compiler suggests code changes for more errors.
- rustc and it's build system have experimental support for building toolchains against MUSL instead of glibc on Linux.
- The compiler defines the
target_env
cfg value, which is used for distinguishing toolchains that are otherwise for the same platform. Presently this is set tognu
for common GNU Linux targets and for MinGW targets, andmusl
for MUSL Linux targets. - The
cargo rustc
command invokes a build with custom flags to rustc. - Android executables are always position independent.
- The
drop_with_repr_extern
lint warns about mixingrepr(C)
withDrop
.
- ~1500 changes, numerous bugfixes
- The vast majority of the standard library is now
#[stable]
. It is no longer possible to use unstable features with a stable build of the compiler. - Many popular crates on crates.io now work on the stable release channel.
- Arithmetic on basic integer types now checks for overflow in debug builds.
- Several restrictions have been added to trait coherence in order to make it easier for upstream authors to change traits without breaking downstream code.
- Digits of binary and octal literals are lexed more eagerly to
improve error messages and macro behavior. For example,
0b1234
is now lexed as0b1234
instead of two tokens,0b1
and234
. - Trait bounds are always invariant, eliminating the need for
the
PhantomFn
andMarkerTrait
lang items, which have been removed. - "-" is no longer a valid character in crate names, the
extern crate "foo" as bar
syntax has been replaced withextern crate foo as bar
, and Cargo now automatically translates "-" in package names to underscore for the crate name. - Lifetime shadowing is an error.
Send
no longer implies'static
.- UFCS now supports trait-less associated paths like
MyType::default()
. - Primitive types now have inherent methods,
obviating the need for extension traits like
SliceExt
. - Methods with
Self: Sized
in theirwhere
clause are considered object-safe, allowing many extension traits likeIteratorExt
to be merged into the traits they extended. - You can now refer to associated types whose
corresponding trait bounds appear only in a
where
clause. - The final bits of OIBIT landed, meaning that traits
like
Send
andSync
are now library-defined. - A Reflect trait was introduced, which means that
downcasting via the
Any
trait is effectively limited to concrete types. This helps retain the potentially-important "parametricity" property: generic code cannot behave differently for different type arguments except in minor ways. - The
unsafe_destructor
feature is now deprecated in favor of the newdropck
. This change is a major reduction in unsafe code.
- The
thread_local
module has been renamed tostd::thread
. - The methods of
IteratorExt
have been moved to theIterator
trait itself. - Several traits that implement Rust's conventions for type
conversions,
AsMut
,AsRef
,From
, andInto
have been centralized in thestd::convert
module. - The
FromError
trait was removed in favor ofFrom
. - The basic sleep function has moved to
std::thread::sleep_ms
. - The
splitn
function now takes ann
parameter that represents the number of items yielded by the returned iterator instead of the number of 'splits'. - On Unix, all file descriptors are
CLOEXEC
by default. - Derived implementations of
PartialOrd
now order enums according to their explicitly-assigned discriminants. - Methods for searching strings are generic over
Pattern
s, implemented presently by&char
,&str
,FnMut(char) -> bool
and some others. - In method resolution, object methods are resolved before inherent methods.
String::from_str
has been deprecated in favor of theFrom
impl,String::from
.io::Error
implementsSync
.- The
words
method on&str
has been replaced withsplit_whitespace
, to avoid answering the tricky question, 'what is a word?' - The new path and IO modules are complete and
#[stable]
. This was the major library focus for this cycle. - The path API was revised to normalize
.
, adjusting the tradeoffs in favor of the most common usage. - A large number of remaining APIs in
std
were also stabilized during this cycle; about 75% of the non-deprecated API surface is now stable. - The new string pattern API landed, which makes the string slice API much more internally consistent and flexible.
- A new set of generic conversion traits replaced many existing ad hoc traits.
- Generic numeric traits were completely removed. This was made possible thanks to inherent methods for primitive types, and the removal gives maximal flexibility for designing a numeric hierarchy in the future.
- The
Fn
traits are now related via inheritance and provide ergonomic blanket implementations. - The
Index
andIndexMut
traits were changed to take the index by value, enabling code likehash_map["string"]
to work. Copy
now inherits fromClone
, meaning that allCopy
data is known to beClone
as well.
- Many errors now have extended explanations that can be accessed with
the
--explain
flag torustc
. - Many new examples have been added to the standard library documentation.
- rustdoc has received a number of improvements focused on completion and polish.
- Metadata was tuned, shrinking binaries by 27%.
- Much headway was made on ecosystem-wide CI, making it possible to compare builds for breakage.
-
~1300 changes, numerous bugfixes
-
Highlights
- The various I/O modules were overhauled to reduce
unnecessary abstractions and provide better interoperation with
the underlying platform. The old
io
module remains temporarily atstd::old_io
. - The standard library now participates in feature gating,
so use of unstable libraries now requires a
#![feature(...)]
attribute. The impact of this change is described on the forum. RFC.
- The various I/O modules were overhauled to reduce
unnecessary abstractions and provide better interoperation with
the underlying platform. The old
-
Language
for
loops now operate on theIntoIterator
trait, which eliminates the need to call.iter()
, etc. to iterate over collections. There are some new subtleties to remember though regarding what sort of iterators various types yield, in particular thatfor foo in bar { }
yields values from a move iterator, destroying the original collection. RFC.- Objects now have default lifetime bounds, so you don't
have to write
Box<Trait+'static>
when you don't care about storing references. RFC. - In types that implement
Drop
, lifetimes must outlive the value. This will soon make it possible to safely implementDrop
for types where#[unsafe_destructor]
is now required. Read the gorgeous RFC for details. - The fully qualified ::X syntax lets you set the Self type for a trait method or associated type. RFC.
- References to types that implement
Deref<U>
now automatically coerce to references to the dereferenced typeU
, e.g.&T where T: Deref<U>
automatically coerces to&U
. This should eliminate many unsightly uses of&*
, as when converting from references to vectors into references to slices. RFC. - The explicit closure kind syntax (
|&:|
,|&mut:|
,|:|
) is obsolete and closure kind is inferred from context. Self
is a keyword.
-
Libraries
- The
Show
andString
formatting traits have been renamed toDebug
andDisplay
to more clearly reflect their related purposes. Automatically getting a string conversion to use withformat!("{:?}", something_to_debug)
is now written#[derive(Debug)]
. - Abstract OS-specific string types,
std::ff::{OsString, OsStr}
, provide strings in platform-specific encodings for easier interop with system APIs. RFC. - The
boxed::into_raw
andBox::from_raw
functions convert betweenBox<T>
and*mut T
, a common pattern for creating raw pointers.
- The
-
Tooling
- Certain long error messages of the form 'expected foo found bar' are now split neatly across multiple lines. Examples in the PR.
- On Unix Rust can be uninstalled by running
/usr/local/lib/rustlib/uninstall.sh
. - The
#[rustc_on_unimplemented]
attribute, requiring the 'on_unimplemented' feature, lets rustc display custom error messages when a trait is expected to be implemented for a type but is not.
-
Misc
- Rust is tested against a LALR grammar, which parses almost all the Rust files that rustc does.
-
~2400 changes, numerous bugfixes
-
Highlights
- The language itself is considered feature complete for 1.0, though there will be many usability improvements and bugfixes before the final release.
- Nearly 50% of the public API surface of the standard library has been declared 'stable'. Those interfaces are unlikely to change before 1.0.
- The long-running debate over integer types has been
settled: Rust will ship with types named
isize
andusize
, rather thanint
anduint
, for pointer-sized integers. Guidelines will be rolled out during the alpha cycle. - Most crates that are not
std
have been moved out of the Rust distribution into the Cargo ecosystem so they can evolve separately and don't need to be stabilized as quickly, including 'time', 'getopts', 'num', 'regex', and 'term'. - Documentation continues to be expanded with more API coverage, more examples, and more in-depth explanations. The guides have been consolidated into The Rust Programming Language.
- "Rust By Example" is now maintained by the Rust team.
- All official Rust binary installers now come with Cargo, the Rust package manager.
-
Language
- Closures have been completely redesigned to be implemented in terms of traits, can now be used as generic type bounds and thus monomorphized and inlined, or via an opaque pointer (boxed) as in the old system. The new system is often referred to as 'unboxed' closures.
- Traits now support associated types, allowing families of related types to be defined together and used generically in powerful ways.
- Enum variants are namespaced by their type names.
where
clauses provide a more versatile and attractive syntax for specifying generic bounds, though the previous syntax remains valid.- Rust again picks a fallback (either i32 or f64) for uninferred numeric types.
- Rust no longer has a runtime of any description, and only supports OS threads, not green threads.
- At long last, Rust has been overhauled for 'dynamically-sized
types' (DST), which integrates 'fat pointers' (object types,
arrays, and
str
) more deeply into the type system, making it more consistent. - Rust now has a general range syntax,
i..j
,i..
, and..j
that produce range types and which, when combined with theIndex
operator and multidispatch, leads to a convenient slice notation,[i..j]
. - The new range syntax revealed an ambiguity in the fixed-length
array syntax, so now fixed length arrays are written
[T; N]
. - The
Copy
trait is no longer implemented automatically. Unsafe pointers no longer implementSync
andSend
so types containing them don't automatically either.Sync
andSend
are now 'unsafe traits' so one can "forcibly" implement them viaunsafe impl
if a type confirms to the requirements for them even though the internals do not (e.g. structs containing unsafe pointers likeArc
). These changes are intended to prevent some footguns and are collectively known as opt-in built-in traits (thoughSync
andSend
will soon become pure library types unknown to the compiler). - Operator traits now take their operands by value, and
comparison traits can use multidispatch to compare one type
against multiple other types, allowing e.g.
String
to be compared with&str
. if let
andwhile let
are no longer feature-gated.- Rust has adopted a more uniform syntax for escaping unicode characters.
macro_rules!
has been declared stable. Though it is a flawed system it is sufficiently popular that it must be usable for 1.0. Effort has gone into future-proofing it in ways that will allow other macro systems to be developed in parallel, and won't otherwise impact the evolution of the language.- The prelude has been pared back significantly such that it is the minimum necessary to support the most pervasive code patterns, and through generalized where clauses many of the prelude extension traits have been consolidated.
- Rust's rudimentary reflection has been removed, as it incurred too much code generation for little benefit.
- Struct variants are no longer feature-gated.
- Trait bounds can be polymorphic over lifetimes. Also known as 'higher-ranked trait bounds', this crucially allows unboxed closures to work.
- Macros invocations surrounded by parens or square brackets and
not terminated by a semicolon are parsed as
expressions, which makes expressions like
vec![1i32, 2, 3].len()
work as expected. - Trait objects now implement their traits automatically, and traits that can be coerced to objects now must be object safe.
- Automatically deriving traits is now done with
#[derive(...)]
not#[deriving(...)]
for consistency with other naming conventions. - Importing the containing module or enum at the same time as
items or variants they contain is now done with
self
instead ofmod
, as in usefoo::{self, bar}
- Glob imports are no longer feature-gated.
- The
box
operator andbox
patterns have been feature-gated pending a redesign. For now unique boxes should be allocated like other containers, withBox::new
.
-
Libraries
- A series of efforts to establish conventions for collections types has resulted in API improvements throughout the standard library.
- New APIs for error handling provide ergonomic interop between error types, and new conventions describe more clearly the recommended error handling strategies in Rust.
- The
fail!
macro has been renamed topanic!
so that it is easier to discuss failure in the context of error handling without making clarifications as to whether you are referring to the 'fail' macro or failure more generally. - On Linux,
OsRng
prefers the new, more reliablegetrandom
syscall when available. - The 'serialize' crate has been renamed 'rustc-serialize' and moved out of the distribution to Cargo. Although it is widely used now, it is expected to be superseded in the near future.
- The
Show
formatter, typically implemented with#[derive(Show)]
is now requested with the{:?}
specifier and is intended for use by all types, for uses such asprintln!
debugging. The newString
formatter must be implemented by hand, uses the{}
specifier, and is intended for full-fidelity conversions of things that can logically be represented as strings.
-
Tooling
- Flexible target specification allows rustc's code generation to be configured to support otherwise-unsupported platforms.
- Rust comes with rust-gdb and rust-lldb scripts that launch their respective debuggers with Rust-appropriate pretty-printing.
- The Windows installation of Rust is distributed with the the MinGW components currently required to link binaries on that platform.
-
Misc
- Nullable enum optimizations have been extended to more types so
that e.g.
Option<Vec<T>>
andOption<String>
take up no more space than the inner types themselves. - Work has begun on supporting AArch64.
- Nullable enum optimizations have been extended to more types so
that e.g.
-
~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
andIndexMut
traits. - The
if let
construct takes a branch only if thelet
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 theSlice
orSliceMut
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
to0...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 thetuple_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 ofextern crate bar = foo
. - Renaming use statements are now written
use foo as bar
instead ofuse bar = foo
. let
andmatch
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 calledSync
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 areSized
, notable exceptions being unsized arrays ([T]
) and trait types. - Closures can return
!
, as in|| -> !
orproc() -> !
. - 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.
- Indexing can be overloaded with the
-
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'sTimespec
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.
-
~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 tof64
. 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 speeder 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.
- All breaking changes to the language or libraries now have their
commit message annotated with
-
~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 asformat!
. - 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 onuse
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 nowextern 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 theDeref
andDerefMut
traits. ~Trait
andproc
no longer haveSend
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 theUnsafe
type. - The #[linkage] attribute was implemented for extern statics/functions.
- The inner attribute syntax has changed from
#[foo];
to#![foo]
. Pod
was renamed toCopy
.
-
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 theResult
type. In order to assist with error handling, atry!
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 toslice
. - 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-reexports. Types such asBufferedReader
are now found atstd::io::BufferedReader
instead ofstd::io::buffered::BufferedReader
. - std:
print
andprintln
are no longer in the prelude, theprint!
andprintln!
macros are intended to be used instead. - std:
Rc
now has aWeak
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 returnOption<T>
instead ofT
+ failing. - std:
fmt::Default
has been renamed tofmt::Show
, and it now has a new deriving mode:#[deriving(Show)]
. - std:
ToStr
is now implemented for all types implementingShow
. - std: The formatting trait methods now take
&self
instead of&T
- std: The
invert()
method on iterators has been renamed torev()
- 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 theReader
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
andE
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
andPort
were renamed toSender
andReceiver
. - std:
Chan::new
is nowchannel()
. - std: A new synchronous channel type has been implemented.
- std: A
select!
macro is now provided for selecting overReceiver
s. - std:
hashmap
andtrie
have been moved tolibcollections
- std:
run
has been rolled intoio::process
- std:
assert_eq!
now uses{}
instead of{:?}
- std: The equality and comparison traits have seen some reorganization.
- std:
rand
has moved tolibrand
. - std:
to_{lower,upper}case
has been implemented forchar
. - 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
. Iflibgreen
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 thesync
library), tweaking and improving various interfaces while dropping redundant functionality. - sync: A new
Barrier
type has been added to thesync
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.
- The
-
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.
- reexported types have their documentation inlined at the location of the first reexport.
- search works across crates that have been rendered to the same output directory.
-
~1800 changes, numerous bugfixes
-
Language
- The
float
type has been removed. Usef32
orf64
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'sGc
orRc
types instead. @mut
has been removed. Usestd::cell::{Cell, RefCell}
instead.- Jumping back to the top of a loop is now done with
continue
instead ofloop
. - 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 inr###"foo"###
. ~fn
is now writtenproc (args) -> retval { ... }
and may only be called once.- The
&fn
type is now written|args| -> ret
to match the literal form. @fn
s have been removed.do
only works with procs in order to make it obvious what the cost ofdo
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
impl
s 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!
andprintfln!
(old-style formatting) removed in favor ofprint!
andprintln!
.mut
works in patterns now, as inlet (mut x, y) = (1, 2);
.- The
extern mod foo (name = "bar")
syntax has been removed. Useextern 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 viaextern "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 ofunsafe
. - 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 thelink_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 thethread_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.
- The
-
Libraries
- std: The
option
andresult
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 ofReader
andWriter
, includingNullReader
,NullWriter
,ZeroReader
,TeeReader
. - std: The reference counted pointer type
extra::rc
moved into std. - std: The
Gc
type in thegc
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 theformat!
macro, as informat!("{}", 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 namedrust_fail
. - std: The
each_key
andeach_value
methods onHashMap
have been replaced by thekeys
andvalues
iterators. - std: Functions dealing with type size and alignment have moved from the
sys
module to themem
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
andends_with
methods added to vectors via theImmutableEqVector
trait, which is in the prelude. - std: Vectors can be indexed with the
get_opt
method, which returnsNone
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 thefail!
macro and retrieved viatask::try
. - std: Methods that produce iterators generally do not have an
_iter
suffix now. - std:
cell::Cell
andcell::RefCell
can be used to introduce mutability roots (mutable fields, etc.). Use instead of e.g.@mut
. - std:
util::ignore
renamed toprelude::drop
. - std: Slices have
sort
andsort_by
methods via theMutableVector
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 thesort
method on mutable slices.
- std: The
-
Tooling
- The
rust
andrusti
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.
- The
-
~2200 changes, numerous bugfixes
-
Language
- The
for
loop syntax has changed to work with theIterator
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 theClone
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
andpriv
modifiers onextern
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 replacefmt!
.print!
andprintln!
write formatted strings (using theformat!
extension) to stdout.write!
andwriteln!
write formatted strings (using theformat!
extension) to the new Writers instd::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 forlet
declarations.- The
#[export_name]
attribute specifies the name of a symbol. unreachable!
can be used to indicate unreachable code, and fails if executed.
- The
-
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, replacinguint::range
and friends. - std:
range_rev
no longer exists. Since range is an iterator it can be reversed withrange(lo, hi).invert()
. - std: The
chain
method on option renamed toand_then
;unwrap_or_default
renamed tounwrap_or
. - std: The
iterator
module was renamed toiter
. - std: Integral types now support the
checked_add
,checked_sub
, andchecked_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 inc_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 tostr::from_utf8
. - std:
pop_opt
andshift_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 ofOption
renamed totake_unwrap
. - std: Added
SharedPort
tocomm
. - std:
Eq
has a default method forne
; onlyeq
is required in implementations. - std:
Ord
has default methods forle
,gt
andge
; onlylt
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 thecollect
method. - std: More complete atomic types in
unstable::atomics
. - std:
comm::PortSet
removed. - std: Mutating methods in the
Set
andMap
traits have been moved into theMutableSet
andMutableMap
traits.Container::is_empty
,Map::contains_key
,MutableMap::insert
, andMutableMap::remove
have default implementations. - std: Various
from_str
functions were removed in favor of a genericfrom_str
which is available in the prelude. - std:
util::unreachable
removed in favor of theunreachable!
macro. - extra:
dlist
, the doubly-linked list was modernized. - extra: Added a
hex
module withToHex
andFromHex
traits. - extra: Added
glob
module, replacingstd::os::glob
. - extra:
rope
was removed. - extra:
deque
was renamed toringbuf
.RingBuf
implementsDeque
. - extra:
net
, andtimer
were removed. The experimental replacements arestd::rt::io::net
andstd::rt::io::timer
. - extra: Iterators implemented for
SmallIntMap
. - extra: Iterators implemented for
Bitv
andBitvSet
. - extra:
SmallIntSet
removed. UseBitvSet
. - 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.
- rustc's debug info generation (
-
~2000 changes, numerous bugfixes
-
Language
impl
s 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 requiresfor
-iterators to returnbool
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 thecopy
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 beSend
, not. - The
#[no_freeze]
attribute makes a type that would otherwise beFreeze
, 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!
andassert!
accept~str
,&'static str
orfmt!
-style argument list.Encodable
,Decodable
,Ord
,TotalOrd
,TotalEq
,DeepClone
,Rand
,Zero
andToStr
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 tostd
. - The
std
crate was renamed toextra
. - 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 ofDrop
renamed todrop
. - std: The
drop
method now takes&mut self
instead of&self
. - std: The prelude no longer reexports 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 toPath
. - std:
mut
module andMut
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. Usetransmute
. - 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
andLinearSet
renamed toHashMap
andHashSet
. - std: Borrowed pointer functions moved from
ptr
toborrow
. - std: Added
os::mkdir_recursive
. - std: Added
os::glob
function performs filesystems globs. - std:
FuzzyEq
renamed toApproxEq
. - std:
Map
now definespop
andswap
methods. - std:
Cell
constructors converted to static methods. - extra:
rc
module adds the reference counted pointers,Rc
andRcMut
. - extra:
flate
module moved fromstd
toextra
. - extra:
fileinput
module for iterating over a series of files. - extra:
Complex
number type andcomplex
module. - extra:
Rational
number type andrational
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.
- The
-
Tooling
unused_variable
lint mode for unused variables (default: warn).unused_unsafe
lint mode for detecting unnecessaryunsafe
blocks (default: warn).unused_mut
lint mode for identifying unusedmut
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).
-
~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 aself
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 ofimpl 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 mutabilityfail
is no longer a keyword. Usefail!()
assert
is no longer a keyword. Useassert!()
log
is no longer a keyword. usedebug!
, etc.- 1-tuples may be represented as
(T,)
- Struct fields may no longer be
mut
. Use inherited mutability,@mut T
,core::mut
orcore::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 tostatic
to correspond to lifetime name, and make room for futurestatic 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 offoo 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]
)
- The self type parameter in traits is now spelled
-
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 previoususe
statementsuse
statements are crate relative, importing from the "top" of the crate by default. Paths may be prefixed withsuper::
orself::
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]
- Types with owned pointers or custom destructors move by default,
eliminating the
-
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 slicedebug!
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 replacementcore::send_map
renamed tocore::hashmap
std::map
removed; replaced withcore::hashmap
std::treemap
reimplemented as an owned balanced treestd::deque
andstd::smallintmap
reimplemented as owned containerscore::trie
added as a fast ordered map for integer keys- Set types added to
core::hashmap
,core::trie
andstd::treemap
Ord
split intoOrd
andTotalOrd
.Ord
is still used to overload the comparison operators, whereasTotalOrd
is used by certain container types
- Added big integers to
-
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.
-
~900 changes, numerous bugfixes
-
Syntax changes
- Removed
<-
move operator - Completed the transition from the
#fmt
extension syntax tofmt!
- 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 projectionEq
andIterBytes
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
- Removed
-
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 tooldcomm
. Still deprecatedrustdoc
andcargo
are libraries now
- New condition handling system in
-
Misc
- Added a preliminary REPL,
rusti
- License changed from MIT to dual MIT/APL2
- Added a preliminary REPL,
-
~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
becamereturn
andalt
becamematch
import
is nowuse
;use is now
extern mod`extern mod { ... }
is nowextern { ... }
use mod
is the recommended way to import modulespub
andpriv
replace deprecated export lists- The syntax of
match
pattern arms now uses fat arrow (=>) main
no longer accepts an args vector; useos::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 typestd::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
- An efficient new intertask communication primitive called the pipe,
along with a number of higher-level channel types, in
-
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
-
~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
-
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
-
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.