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RELEASES.md
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Version 1.59.0 (2022-02-24)
==========================
Language
--------
- [Stabilize default arguments for const parameters and remove the ordering restriction for type and const parameters][90207]
- [Stabilize destructuring assignment][90521]
- [Relax private in public lint on generic bounds and where clauses of trait impls][90586]
- [Stabilize asm! and global_asm! for x86, x86_64, ARM, Aarch64, and RISC-V][91728]
Compiler
--------
- [Stabilize new symbol mangling format, leaving it opt-in (-Csymbol-mangling-version=v0)][90128]
- [Emit LLVM optimization remarks when enabled with `-Cremark`][90833]
- [Fix sparc64 ABI for aggregates with floating point members][91003]
- [Warn when a `#[test]`-like built-in attribute macro is present multiple times.][91172]
- [Add support for riscv64gc-unknown-freebsd][91284]
- [Stabilize `-Z emit-future-incompat` as `--json future-incompat`][91535]
- [Soft disable incremental compilation][94124]
This release disables incremental compilation, unless the user has explicitly
opted in via the newly added RUSTC_FORCE_INCREMENTAL=1 environment variable.
This is due to a known and relatively frequently occurring bug in incremental
compilation, which causes builds to issue internal compiler errors. This
particular bug is already fixed on nightly, but that fix has not yet rolled out
to stable and is deemed too risky for a direct stable backport.
As always, we encourage users to test with nightly and report bugs so that we
can track failures and fix issues earlier.
See [94124] for more details.
[94124]: https://github.com/rust-lang/rust/issues/94124
Libraries
---------
- [Remove unnecessary bounds for some Hash{Map,Set} methods][91593]
Stabilized APIs
---------------
- [`std::thread::available_parallelism`][available_parallelism]
- [`Result::copied`][result-copied]
- [`Result::cloned`][result-cloned]
- [`arch::asm!`][asm]
- [`arch::global_asm!`][global_asm]
- [`ops::ControlFlow::is_break`][is_break]
- [`ops::ControlFlow::is_continue`][is_continue]
- [`TryFrom<char> for u8`][try_from_char_u8]
- [`char::TryFromCharError`][try_from_char_err]
implementing `Clone`, `Debug`, `Display`, `PartialEq`, `Copy`, `Eq`, `Error`
- [`iter::zip`][zip]
- [`NonZeroU8::is_power_of_two`][is_power_of_two8]
- [`NonZeroU16::is_power_of_two`][is_power_of_two16]
- [`NonZeroU32::is_power_of_two`][is_power_of_two32]
- [`NonZeroU64::is_power_of_two`][is_power_of_two64]
- [`NonZeroU128::is_power_of_two`][is_power_of_two128]
- [`NonZeroUsize::is_power_of_two`][is_power_of_two_usize]
- [`DoubleEndedIterator for ToLowercase`][lowercase]
- [`DoubleEndedIterator for ToUppercase`][uppercase]
- [`TryFrom<&mut [T]> for [T; N]`][tryfrom_ref_arr]
- [`UnwindSafe for Once`][unwindsafe_once]
- [`RefUnwindSafe for Once`][refunwindsafe_once]
- [armv8 neon intrinsics for aarch64][stdarch/1266]
Const-stable:
- [`mem::MaybeUninit::as_ptr`][muninit_ptr]
- [`mem::MaybeUninit::assume_init`][muninit_init]
- [`mem::MaybeUninit::assume_init_ref`][muninit_init_ref]
- [`ffi::CStr::from_bytes_with_nul_unchecked`][cstr_from_bytes]
Cargo
-----
- [Stabilize the `strip` profile option][cargo/10088]
- [Stabilize future-incompat-report][cargo/10165]
- [Support abbreviating `--release` as `-r`][cargo/10133]
- [Support `term.quiet` configuration][cargo/10152]
- [Remove `--host` from cargo {publish,search,login}][cargo/10145]
Compatibility Notes
-------------------
- [Refactor weak symbols in std::sys::unix][90846]
This may add new, versioned, symbols when building with a newer glibc, as the
standard library uses weak linkage rather than dynamically attempting to load
certain symbols at runtime.
- [Deprecate crate_type and crate_name nested inside `#![cfg_attr]`][83744]
This adds a future compatibility lint to supporting the use of cfg_attr
wrapping either crate_type or crate_name specification within Rust files;
it is recommended that users migrate to setting the equivalent command line
flags.
- [Remove effect of `#[no_link]` attribute on name resolution][92034]
This may expose new names, leading to conflicts with preexisting names in a
given namespace and a compilation failure.
- [Cargo will document libraries before binaries.][cargo/10172]
- [Respect doc=false in dependencies, not just the root crate][cargo/10201]
- [Weaken guarantee around advancing underlying iterators in zip][83791]
- [Make split_inclusive() on an empty slice yield an empty output][89825]
- [Update std::env::temp_dir to use GetTempPath2 on Windows when available.][89999]
- [unreachable! was updated to match other formatting macro behavior on Rust 2021][92137]
Internal Changes
----------------
These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.
- [Fix many cases of normalization-related ICEs][91255]
- [Replace dominators algorithm with simple Lengauer-Tarjan][85013]
- [Store liveness in interval sets for region inference][90637]
- [Remove `in_band_lifetimes` from the compiler and standard library, in preparation for removing this
unstable feature.][91867]
[91867]: https://github.com/rust-lang/rust/issues/91867
[83744]: https://github.com/rust-lang/rust/pull/83744/
[83791]: https://github.com/rust-lang/rust/pull/83791/
[85013]: https://github.com/rust-lang/rust/pull/85013/
[89825]: https://github.com/rust-lang/rust/pull/89825/
[89999]: https://github.com/rust-lang/rust/pull/89999/
[90128]: https://github.com/rust-lang/rust/pull/90128/
[90207]: https://github.com/rust-lang/rust/pull/90207/
[90521]: https://github.com/rust-lang/rust/pull/90521/
[90586]: https://github.com/rust-lang/rust/pull/90586/
[90637]: https://github.com/rust-lang/rust/pull/90637/
[90833]: https://github.com/rust-lang/rust/pull/90833/
[90846]: https://github.com/rust-lang/rust/pull/90846/
[91003]: https://github.com/rust-lang/rust/pull/91003/
[91172]: https://github.com/rust-lang/rust/pull/91172/
[91255]: https://github.com/rust-lang/rust/pull/91255/
[91284]: https://github.com/rust-lang/rust/pull/91284/
[91535]: https://github.com/rust-lang/rust/pull/91535/
[91593]: https://github.com/rust-lang/rust/pull/91593/
[91728]: https://github.com/rust-lang/rust/pull/91728/
[91878]: https://github.com/rust-lang/rust/pull/91878/
[91896]: https://github.com/rust-lang/rust/pull/91896/
[91926]: https://github.com/rust-lang/rust/pull/91926/
[91984]: https://github.com/rust-lang/rust/pull/91984/
[92020]: https://github.com/rust-lang/rust/pull/92020/
[92034]: https://github.com/rust-lang/rust/pull/92034/
[92137]: https://github.com/rust-lang/rust/pull/92137/
[92483]: https://github.com/rust-lang/rust/pull/92483/
[cargo/10088]: https://github.com/rust-lang/cargo/pull/10088/
[cargo/10133]: https://github.com/rust-lang/cargo/pull/10133/
[cargo/10145]: https://github.com/rust-lang/cargo/pull/10145/
[cargo/10152]: https://github.com/rust-lang/cargo/pull/10152/
[cargo/10165]: https://github.com/rust-lang/cargo/pull/10165/
[cargo/10172]: https://github.com/rust-lang/cargo/pull/10172/
[cargo/10201]: https://github.com/rust-lang/cargo/pull/10201/
[cargo/10269]: https://github.com/rust-lang/cargo/pull/10269/
[cstr_from_bytes]: https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.from_bytes_with_nul_unchecked
[muninit_ptr]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_ptr
[muninit_init]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init
[muninit_init_ref]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
[unwindsafe_once]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#impl-UnwindSafe
[refunwindsafe_once]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#impl-RefUnwindSafe
[tryfrom_ref_arr]: https://doc.rust-lang.org/stable/std/convert/trait.TryFrom.html#impl-TryFrom%3C%26%27_%20mut%20%5BT%5D%3E
[lowercase]: https://doc.rust-lang.org/stable/std/char/struct.ToLowercase.html#impl-DoubleEndedIterator
[uppercase]: https://doc.rust-lang.org/stable/std/char/struct.ToUppercase.html#impl-DoubleEndedIterator
[try_from_char_err]: https://doc.rust-lang.org/stable/std/char/struct.TryFromCharError.html
[available_parallelism]: https://doc.rust-lang.org/stable/std/thread/fn.available_parallelism.html
[result-copied]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.copied
[result-cloned]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.cloned
[asm]: https://doc.rust-lang.org/stable/core/arch/macro.asm.html
[global_asm]: https://doc.rust-lang.org/stable/core/arch/macro.global_asm.html
[is_break]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html#method.is_break
[is_continue]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html#method.is_continue
[try_from_char_u8]: https://doc.rust-lang.org/stable/std/primitive.char.html#impl-TryFrom%3Cchar%3E
[zip]: https://doc.rust-lang.org/stable/std/iter/fn.zip.html
[is_power_of_two8]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU8.html#method.is_power_of_two
[is_power_of_two16]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU16.html#method.is_power_of_two
[is_power_of_two32]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU32.html#method.is_power_of_two
[is_power_of_two64]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU64.html#method.is_power_of_two
[is_power_of_two128]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU128.html#method.is_power_of_two
[is_power_of_two_usize]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroUsize.html#method.is_power_of_two
[stdarch/1266]: https://github.com/rust-lang/stdarch/pull/1266
Version 1.58.1 (2022-01-19)
===========================
* Fix race condition in `std::fs::remove_dir_all` ([CVE-2022-21658])
* [Handle captured arguments in the `useless_format` Clippy lint][clippy/8295]
* [Move `non_send_fields_in_send_ty` Clippy lint to nursery][clippy/8075]
* [Fix wrong error message displayed when some imports are missing][91254]
* [Fix rustfmt not formatting generated files from stdin][92912]
[CVE-2022-21658]: https://www.cve.org/CVERecord?id=CVE-2022-21658
[91254]: https://github.com/rust-lang/rust/pull/91254
[92912]: https://github.com/rust-lang/rust/pull/92912
[clippy/8075]: https://github.com/rust-lang/rust-clippy/pull/8075
[clippy/8295]: https://github.com/rust-lang/rust-clippy/pull/8295
Version 1.58.0 (2022-01-13)
==========================
Language
--------
- [Format strings can now capture arguments simply by writing `{ident}` in the string.][90473] This works in all macros accepting format strings. Support for this in `panic!` (`panic!("{ident}")`) requires the 2021 edition; panic invocations in previous editions that appear to be trying to use this will result in a warning lint about not having the intended effect.
- [`*const T` pointers can now be dereferenced in const contexts.][89551]
- [The rules for when a generic struct implements `Unsize` have been relaxed.][90417]
Compiler
--------
- [Add LLVM CFI support to the Rust compiler][89652]
- [Stabilize -Z strip as -C strip][90058]. Note that while release builds already don't add debug symbols for the code you compile, the compiled standard library that ships with Rust includes debug symbols, so you may want to use the `strip` option to remove these symbols to produce smaller release binaries. Note that this release only includes support in rustc, not directly in cargo.
- [Add support for LLVM coverage mapping format versions 5 and 6][91207]
- [Emit LLVM optimization remarks when enabled with `-Cremark`][90833]
- [Update the minimum external LLVM to 12][90175]
- [Add `x86_64-unknown-none` at Tier 3*][89062]
- [Build musl dist artifacts with debuginfo enabled][90733]. When building release binaries using musl, you may want to use the newly stabilized strip option to remove these debug symbols, reducing the size of your binaries.
- [Don't abort compilation after giving a lint error][87337]
- [Error messages point at the source of trait bound obligations in more places][89580]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [All remaining functions in the standard library have `#[must_use]` annotations where appropriate][89692], producing a warning when ignoring their return value. This helps catch mistakes such as expecting a function to mutate a value in place rather than return a new value.
- [Paths are automatically canonicalized on Windows for operations that support it][89174]
- [Re-enable debug checks for `copy` and `copy_nonoverlapping`][90041]
- [Implement `RefUnwindSafe` for `Rc<T>`][87467]
- [Make RSplit<T, P>: Clone not require T: Clone][90117]
- [Implement `Termination` for `Result<Infallible, E>`][88601]. This allows writing `fn main() -> Result<Infallible, ErrorType>`, for a program whose successful exits never involve returning from `main` (for instance, a program that calls `exit`, or that uses `exec` to run another program).
Stabilized APIs
---------------
- [`Metadata::is_symlink`]
- [`Path::is_symlink`]
- [`{integer}::saturating_div`]
- [`Option::unwrap_unchecked`]
- [`Result::unwrap_unchecked`]
- [`Result::unwrap_err_unchecked`]
- [`File::options`]
These APIs are now usable in const contexts:
- [`Duration::new`]
- [`Duration::checked_add`]
- [`Duration::saturating_add`]
- [`Duration::checked_sub`]
- [`Duration::saturating_sub`]
- [`Duration::checked_mul`]
- [`Duration::saturating_mul`]
- [`Duration::checked_div`]
Cargo
-----
- [Add --message-format for install command][cargo/10107]
- [Warn when alias shadows external subcommand][cargo/10082]
Rustdoc
-------
- [Show all Deref implementations recursively in rustdoc][90183]
- [Use computed visibility in rustdoc][88447]
Compatibility Notes
-------------------
- [Try all stable method candidates first before trying unstable ones][90329]. This change ensures that adding new nightly-only methods to the Rust standard library will not break code invoking methods of the same name from traits outside the standard library.
- Windows: [`std::process::Command` will no longer search the current directory for executables.][87704]
- [All proc-macro backward-compatibility lints are now deny-by-default.][88041]
- [proc_macro: Append .0 to unsuffixed float if it would otherwise become int token][90297]
- [Refactor weak symbols in std::sys::unix][90846]. This optimizes accesses to glibc functions, by avoiding the use of dlopen. This does not increase the [minimum expected version of glibc](https://doc.rust-lang.org/nightly/rustc/platform-support.html). However, software distributions that use symbol versions to detect library dependencies, and which take weak symbols into account in that analysis, may detect rust binaries as requiring newer versions of glibc.
- [rustdoc now rejects some unexpected semicolons in doctests][91026]
Internal Changes
----------------
These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.
- [Implement coherence checks for negative trait impls][90104]
- [Add rustc lint, warning when iterating over hashmaps][89558]
- [Optimize live point computation][90491]
- [Enable verification for 1/32nd of queries loaded from disk][90361]
- [Implement version of normalize_erasing_regions that allows for normalization failure][91255]
[87337]: https://github.com/rust-lang/rust/pull/87337/
[87467]: https://github.com/rust-lang/rust/pull/87467/
[87704]: https://github.com/rust-lang/rust/pull/87704/
[88041]: https://github.com/rust-lang/rust/pull/88041/
[88447]: https://github.com/rust-lang/rust/pull/88447/
[88601]: https://github.com/rust-lang/rust/pull/88601/
[89062]: https://github.com/rust-lang/rust/pull/89062/
[89174]: https://github.com/rust-lang/rust/pull/89174/
[89551]: https://github.com/rust-lang/rust/pull/89551/
[89558]: https://github.com/rust-lang/rust/pull/89558/
[89580]: https://github.com/rust-lang/rust/pull/89580/
[89652]: https://github.com/rust-lang/rust/pull/89652/
[90041]: https://github.com/rust-lang/rust/pull/90041/
[90058]: https://github.com/rust-lang/rust/pull/90058/
[90104]: https://github.com/rust-lang/rust/pull/90104/
[90117]: https://github.com/rust-lang/rust/pull/90117/
[90175]: https://github.com/rust-lang/rust/pull/90175/
[90183]: https://github.com/rust-lang/rust/pull/90183/
[90297]: https://github.com/rust-lang/rust/pull/90297/
[90329]: https://github.com/rust-lang/rust/pull/90329/
[90361]: https://github.com/rust-lang/rust/pull/90361/
[90417]: https://github.com/rust-lang/rust/pull/90417/
[90473]: https://github.com/rust-lang/rust/pull/90473/
[90491]: https://github.com/rust-lang/rust/pull/90491/
[90733]: https://github.com/rust-lang/rust/pull/90733/
[90833]: https://github.com/rust-lang/rust/pull/90833/
[90846]: https://github.com/rust-lang/rust/pull/90846/
[91026]: https://github.com/rust-lang/rust/pull/91026/
[91207]: https://github.com/rust-lang/rust/pull/91207/
[91255]: https://github.com/rust-lang/rust/pull/91255/
[cargo/10082]: https://github.com/rust-lang/cargo/pull/10082/
[cargo/10107]: https://github.com/rust-lang/cargo/pull/10107/
[`Metadata::is_symlink`]: https://doc.rust-lang.org/stable/std/fs/struct.Metadata.html#method.is_symlink
[`Path::is_symlink`]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.is_symlink
[`{integer}::saturating_div`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.saturating_div
[`Option::unwrap_unchecked`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unwrap_unchecked
[`Result::unwrap_unchecked`]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.unwrap_unchecked
[`Result::unwrap_err_unchecked`]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.unwrap_err_unchecked
[`File::options`]: https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.options
[`Duration::new`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.new
Version 1.57.0 (2021-12-02)
==========================
Language
--------
- [Macro attributes may follow `#[derive]` and will see the original (pre-`cfg`) input.][87220]
- [Accept curly-brace macros in expressions, like `m!{ .. }.method()` and `m!{ .. }?`.][88690]
- [Allow panicking in constant evaluation.][89508]
- [Ignore derived `Clone` and `Debug` implementations during dead code analysis.][85200]
Compiler
--------
- [Create more accurate debuginfo for vtables.][89597]
- [Add `armv6k-nintendo-3ds` at Tier 3\*.][88529]
- [Add `armv7-unknown-linux-uclibceabihf` at Tier 3\*.][88952]
- [Add `m68k-unknown-linux-gnu` at Tier 3\*.][88321]
- [Add SOLID targets at Tier 3\*:][86191] `aarch64-kmc-solid_asp3`, `armv7a-kmc-solid_asp3-eabi`, `armv7a-kmc-solid_asp3-eabihf`
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Avoid allocations and copying in `Vec::leak`][89337]
- [Add `#[repr(i8)]` to `Ordering`][89507]
- [Optimize `File::read_to_end` and `read_to_string`][89582]
- [Update to Unicode 14.0][89614]
- [Many more functions are marked `#[must_use]`][89692], producing a warning
when ignoring their return value. This helps catch mistakes such as expecting
a function to mutate a value in place rather than return a new value.
Stabilised APIs
---------------
- [`[T; N]::as_mut_slice`][`array::as_mut_slice`]
- [`[T; N]::as_slice`][`array::as_slice`]
- [`collections::TryReserveError`]
- [`HashMap::try_reserve`]
- [`HashSet::try_reserve`]
- [`String::try_reserve`]
- [`String::try_reserve_exact`]
- [`Vec::try_reserve`]
- [`Vec::try_reserve_exact`]
- [`VecDeque::try_reserve`]
- [`VecDeque::try_reserve_exact`]
- [`Iterator::map_while`]
- [`iter::MapWhile`]
- [`proc_macro::is_available`]
- [`Command::get_program`]
- [`Command::get_args`]
- [`Command::get_envs`]
- [`Command::get_current_dir`]
- [`CommandArgs`]
- [`CommandEnvs`]
These APIs are now usable in const contexts:
- [`hint::unreachable_unchecked`]
Cargo
-----
- [Stabilize custom profiles][cargo/9943]
Compatibility notes
-------------------
- [Ignore derived `Clone` and `Debug` implementations during dead code analysis.][85200]
This will break some builds that set `#![deny(dead_code)]`.
Internal changes
----------------
These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.
- [Added an experimental backend for codegen with `libgccjit`.][87260]
[85200]: https://github.com/rust-lang/rust/pull/85200/
[86191]: https://github.com/rust-lang/rust/pull/86191/
[87220]: https://github.com/rust-lang/rust/pull/87220/
[87260]: https://github.com/rust-lang/rust/pull/87260/
[88321]: https://github.com/rust-lang/rust/pull/88321/
[88529]: https://github.com/rust-lang/rust/pull/88529/
[88690]: https://github.com/rust-lang/rust/pull/88690/
[88952]: https://github.com/rust-lang/rust/pull/88952/
[89337]: https://github.com/rust-lang/rust/pull/89337/
[89507]: https://github.com/rust-lang/rust/pull/89507/
[89508]: https://github.com/rust-lang/rust/pull/89508/
[89582]: https://github.com/rust-lang/rust/pull/89582/
[89597]: https://github.com/rust-lang/rust/pull/89597/
[89614]: https://github.com/rust-lang/rust/pull/89614/
[89692]: https://github.com/rust-lang/rust/issues/89692/
[cargo/9943]: https://github.com/rust-lang/cargo/pull/9943/
[`array::as_mut_slice`]: https://doc.rust-lang.org/std/primitive.array.html#method.as_mut_slice
[`array::as_slice`]: https://doc.rust-lang.org/std/primitive.array.html#method.as_slice
[`collections::TryReserveError`]: https://doc.rust-lang.org/std/collections/struct.TryReserveError.html
[`HashMap::try_reserve`]: https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.try_reserve
[`HashSet::try_reserve`]: https://doc.rust-lang.org/std/collections/hash_set/struct.HashSet.html#method.try_reserve
[`String::try_reserve`]: https://doc.rust-lang.org/alloc/string/struct.String.html#method.try_reserve
[`String::try_reserve_exact`]: https://doc.rust-lang.org/alloc/string/struct.String.html#method.try_reserve_exact
[`Vec::try_reserve`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.try_reserve
[`Vec::try_reserve_exact`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.try_reserve_exact
[`VecDeque::try_reserve`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.try_reserve
[`VecDeque::try_reserve_exact`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.try_reserve_exact
[`Iterator::map_while`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.map_while
[`iter::MapWhile`]: https://doc.rust-lang.org/std/iter/struct.MapWhile.html
[`proc_macro::is_available`]: https://doc.rust-lang.org/proc_macro/fn.is_available.html
[`Command::get_program`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_program
[`Command::get_args`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_args
[`Command::get_envs`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_envs
[`Command::get_current_dir`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_current_dir
[`CommandArgs`]: https://doc.rust-lang.org/std/process/struct.CommandArgs.html
[`CommandEnvs`]: https://doc.rust-lang.org/std/process/struct.CommandEnvs.html
Version 1.56.1 (2021-11-01)
===========================
- New lints to detect the presence of bidirectional-override Unicode
codepoints in the compiled source code ([CVE-2021-42574])
[CVE-2021-42574]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-42574
Version 1.56.0 (2021-10-21)
========================
Language
--------
- [The 2021 Edition is now stable.][rust#88100]
See [the edition guide][rust-2021-edition-guide] for more details.
- [The pattern in `binding @ pattern` can now also introduce new bindings.][rust#85305]
- [Union field access is permitted in `const fn`.][rust#85769]
[rust-2021-edition-guide]: https://doc.rust-lang.org/nightly/edition-guide/rust-2021/index.html
Compiler
--------
- [Upgrade to LLVM 13.][rust#87570]
- [Support memory, address, and thread sanitizers on aarch64-unknown-freebsd.][rust#88023]
- [Allow specifying a deployment target version for all iOS targets][rust#87699]
- [Warnings can be forced on with `--force-warn`.][rust#87472]
This feature is primarily intended for usage by `cargo fix`, rather than end users.
- [Promote `aarch64-apple-ios-sim` to Tier 2\*.][rust#87760]
- [Add `powerpc-unknown-freebsd` at Tier 3\*.][rust#87370]
- [Add `riscv32imc-esp-espidf` at Tier 3\*.][rust#87666]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Allow writing of incomplete UTF-8 sequences via stdout/stderr on Windows.][rust#83342]
The Windows console still requires valid Unicode, but this change allows
splitting a UTF-8 character across multiple write calls. This allows, for
instance, programs that just read and write data buffers (e.g. copying a file
to stdout) without regard for Unicode or character boundaries.
- [Prefer `AtomicU{64,128}` over Mutex for Instant backsliding protection.][rust#83093]
For this use case, atomics scale much better under contention.
- [Implement `Extend<(A, B)>` for `(Extend<A>, Extend<B>)`][rust#85835]
- [impl Default, Copy, Clone for std::io::Sink and std::io::Empty][rust#86744]
- [`impl From<[(K, V); N]>` for all collections.][rust#84111]
- [Remove `P: Unpin` bound on impl Future for Pin.][rust#81363]
- [Treat invalid environment variable names as non-existent.][rust#86183]
Previously, the environment functions would panic if given a variable name
with an internal null character or equal sign (`=`). Now, these functions will
just treat such names as non-existent variables, since the OS cannot represent
the existence of a variable with such a name.
Stabilised APIs
---------------
- [`std::os::unix::fs::chroot`]
- [`UnsafeCell::raw_get`]
- [`BufWriter::into_parts`]
- [`core::panic::{UnwindSafe, RefUnwindSafe, AssertUnwindSafe}`]
These APIs were previously stable in `std`, but are now also available in `core`.
- [`Vec::shrink_to`]
- [`String::shrink_to`]
- [`OsString::shrink_to`]
- [`PathBuf::shrink_to`]
- [`BinaryHeap::shrink_to`]
- [`VecDeque::shrink_to`]
- [`HashMap::shrink_to`]
- [`HashSet::shrink_to`]
These APIs are now usable in const contexts:
- [`std::mem::transmute`]
- [`[T]::first`][`slice::first`]
- [`[T]::split_first`][`slice::split_first`]
- [`[T]::last`][`slice::last`]
- [`[T]::split_last`][`slice::split_last`]
Cargo
-----
- [Cargo supports specifying a minimum supported Rust version in Cargo.toml.][`rust-version`]
This has no effect at present on dependency version selection.
We encourage crates to specify their minimum supported Rust version, and we encourage CI systems
that support Rust code to include a crate's specified minimum version in the test matrix for that
crate by default.
Compatibility notes
-------------------
- [Update to new argument parsing rules on Windows.][rust#87580]
This adjusts Rust's standard library to match the behavior of the standard
libraries for C/C++. The rules have changed slightly over time, and this PR
brings us to the latest set of rules (changed in 2008).
- [Disallow the aapcs calling convention on aarch64][rust#88399]
This was already not supported by LLVM; this change surfaces this lack of
support with a better error message.
- [Make `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` warn by default][rust#87385]
- [Warn when an escaped newline skips multiple lines.][rust#87671]
- [Calls to `libc::getpid` / `std::process::id` from `Command::pre_exec`
may return different values on glibc <= 2.24.][rust#81825]
Rust now invokes the `clone3` system call directly, when available, to use new functionality
available via that system call. Older versions of glibc cache the result of `getpid`, and only
update that cache when calling glibc's clone/fork functions, so a direct system call bypasses
that cache update. glibc 2.25 and newer no longer cache `getpid` for exactly this reason.
Internal changes
----------------
These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.
- [LLVM is compiled with PGO in published x86_64-unknown-linux-gnu artifacts.][rust#88069]
This improves the performance of most Rust builds.
- [Unify representation of macros in internal data structures.][rust#88019]
This change fixes a host of bugs with the handling of macros by the compiler,
as well as rustdoc.
[`std::os::unix::fs::chroot`]: https://doc.rust-lang.org/stable/std/os/unix/fs/fn.chroot.html
[`UnsafeCell::raw_get`]: https://doc.rust-lang.org/stable/std/cell/struct.UnsafeCell.html#method.raw_get
[`BufWriter::into_parts`]: https://doc.rust-lang.org/stable/std/io/struct.BufWriter.html#method.into_parts
[`core::panic::{UnwindSafe, RefUnwindSafe, AssertUnwindSafe}`]: https://github.com/rust-lang/rust/pull/84662
[`Vec::shrink_to`]: https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.shrink_to
[`String::shrink_to`]: https://doc.rust-lang.org/stable/std/string/struct.String.html#method.shrink_to
[`OsString::shrink_to`]: https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.shrink_to
[`PathBuf::shrink_to`]: https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.shrink_to
[`BinaryHeap::shrink_to`]: https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.shrink_to
[`VecDeque::shrink_to`]: https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.shrink_to
[`HashMap::shrink_to`]: https://doc.rust-lang.org/stable/std/collections/hash_map/struct.HashMap.html#method.shrink_to
[`HashSet::shrink_to`]: https://doc.rust-lang.org/stable/std/collections/hash_set/struct.HashSet.html#method.shrink_to
[`std::mem::transmute`]: https://doc.rust-lang.org/stable/std/mem/fn.transmute.html
[`slice::first`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first
[`slice::split_first`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first
[`slice::last`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last
[`slice::split_last`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last
[`rust-version`]: https://doc.rust-lang.org/nightly/cargo/reference/manifest.html#the-rust-version-field
[rust#87671]: https://github.com/rust-lang/rust/pull/87671
[rust#86183]: https://github.com/rust-lang/rust/pull/86183
[rust#87385]: https://github.com/rust-lang/rust/pull/87385
[rust#88100]: https://github.com/rust-lang/rust/pull/88100
[rust#85305]: https://github.com/rust-lang/rust/pull/85305
[rust#88069]: https://github.com/rust-lang/rust/pull/88069
[rust#87472]: https://github.com/rust-lang/rust/pull/87472
[rust#87699]: https://github.com/rust-lang/rust/pull/87699
[rust#87570]: https://github.com/rust-lang/rust/pull/87570
[rust#88023]: https://github.com/rust-lang/rust/pull/88023
[rust#87760]: https://github.com/rust-lang/rust/pull/87760
[rust#87370]: https://github.com/rust-lang/rust/pull/87370
[rust#87580]: https://github.com/rust-lang/rust/pull/87580
[rust#83342]: https://github.com/rust-lang/rust/pull/83342
[rust#83093]: https://github.com/rust-lang/rust/pull/83093
[rust#85835]: https://github.com/rust-lang/rust/pull/85835
[rust#86744]: https://github.com/rust-lang/rust/pull/86744
[rust#81363]: https://github.com/rust-lang/rust/pull/81363
[rust#84111]: https://github.com/rust-lang/rust/pull/84111
[rust#85769]: https://github.com/rust-lang/rust/pull/85769#issuecomment-854363720
[rust#88399]: https://github.com/rust-lang/rust/pull/88399
[rust#81825]: https://github.com/rust-lang/rust/pull/81825#issuecomment-808406918
[rust#88019]: https://github.com/rust-lang/rust/pull/88019
[rust#87666]: https://github.com/rust-lang/rust/pull/87666
Version 1.55.0 (2021-09-09)
============================
Language
--------
- [You can now write open "from" range patterns (`X..`), which will start at `X` and
will end at the maximum value of the integer.][83918]
- [You can now explicitly import the prelude of different editions
through `std::prelude` (e.g. `use std::prelude::rust_2021::*;`).][86294]
Compiler
--------
- [Added tier 3\* support for `powerpc64le-unknown-freebsd`.][83572]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Updated std's float parsing to use the Eisel-Lemire algorithm.][86761]
These improvements should in general provide faster string parsing of floats,
no longer reject certain valid floating point values, and reduce
the produced code size for non-stripped artifacts.
- [`string::Drain` now implements `AsRef<str>` and `AsRef<[u8]>`.][86858]
Stabilised APIs
---------------
- [`Bound::cloned`]
- [`Drain::as_str`]
- [`IntoInnerError::into_error`]
- [`IntoInnerError::into_parts`]
- [`MaybeUninit::assume_init_mut`]
- [`MaybeUninit::assume_init_ref`]
- [`MaybeUninit::write`]
- [`array::map`]
- [`ops::ControlFlow`]
- [`x86::_bittest`]
- [`x86::_bittestandcomplement`]
- [`x86::_bittestandreset`]
- [`x86::_bittestandset`]
- [`x86_64::_bittest64`]
- [`x86_64::_bittestandcomplement64`]
- [`x86_64::_bittestandreset64`]
- [`x86_64::_bittestandset64`]
The following previously stable functions are now `const`.
- [`str::from_utf8_unchecked`]
Cargo
-----
- [Cargo will now deduplicate compiler diagnostics to the terminal when invoking
rustc in parallel such as when using `cargo test`.][cargo/9675]
- [The package definition in `cargo metadata` now includes the `"default_run"`
field from the manifest.][cargo/9550]
- [Added `cargo d` as an alias for `cargo doc`.][cargo/9680]
- [Added `{lib}` as formatting option for `cargo tree` to print the `"lib_name"`
of packages.][cargo/9663]
Rustdoc
-------
- [Added "Go to item on exact match" search option.][85876]
- [The "Implementors" section on traits no longer shows redundant
method definitions.][85970]
- [Trait implementations are toggled open by default.][86260] This should make the
implementations more searchable by tools like `CTRL+F` in your browser.
- [Intra-doc links should now correctly resolve associated items (e.g. methods)
through type aliases.][86334]
- [Traits which are marked with `#[doc(hidden)]` will no longer appear in the
"Trait Implementations" section.][86513]
Compatibility Notes
-------------------
- [std functions that return an `io::Error` will no longer use the
`ErrorKind::Other` variant.][85746] This is to better reflect that these
kinds of errors could be categorised [into newer more specific `ErrorKind`
variants][79965], and that they do not represent a user error.
- [Using environment variable names with `process::Command` on Windows now
behaves as expected.][85270] Previously using envionment variables with
`Command` would cause them to be ASCII-uppercased.
- [Rustdoc will now warn on using rustdoc lints that aren't prefixed
with `rustdoc::`][86849]
- `RUSTFLAGS` is no longer set for build scripts. Build scripts
should use `CARGO_ENCODED_RUSTFLAGS` instead. See the
[documentation](https://doc.rust-lang.org/nightly/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts)
for more details.
[86849]: https://github.com/rust-lang/rust/pull/86849
[86513]: https://github.com/rust-lang/rust/pull/86513
[86334]: https://github.com/rust-lang/rust/pull/86334
[86260]: https://github.com/rust-lang/rust/pull/86260
[85970]: https://github.com/rust-lang/rust/pull/85970
[85876]: https://github.com/rust-lang/rust/pull/85876
[83572]: https://github.com/rust-lang/rust/pull/83572
[86294]: https://github.com/rust-lang/rust/pull/86294
[86858]: https://github.com/rust-lang/rust/pull/86858
[86761]: https://github.com/rust-lang/rust/pull/86761
[85746]: https://github.com/rust-lang/rust/pull/85746
[85270]: https://github.com/rust-lang/rust/pull/85270
[83918]: https://github.com/rust-lang/rust/pull/83918
[79965]: https://github.com/rust-lang/rust/pull/79965
[cargo/9663]: https://github.com/rust-lang/cargo/pull/9663
[cargo/9675]: https://github.com/rust-lang/cargo/pull/9675
[cargo/9550]: https://github.com/rust-lang/cargo/pull/9550
[cargo/9680]: https://github.com/rust-lang/cargo/pull/9680
[`array::map`]: https://doc.rust-lang.org/stable/std/primitive.array.html#method.map
[`Bound::cloned`]: https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.cloned
[`Drain::as_str`]: https://doc.rust-lang.org/stable/std/string/struct.Drain.html#method.as_str
[`IntoInnerError::into_error`]: https://doc.rust-lang.org/stable/std/io/struct.IntoInnerError.html#method.into_error
[`IntoInnerError::into_parts`]: https://doc.rust-lang.org/stable/std/io/struct.IntoInnerError.html#method.into_parts
[`MaybeUninit::assume_init_mut`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_mut
[`MaybeUninit::assume_init_ref`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
[`MaybeUninit::write`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.write
[`ops::ControlFlow`]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html
[`str::from_utf8_unchecked`]: https://doc.rust-lang.org/stable/std/str/fn.from_utf8_unchecked.html
[`x86::_bittest`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittest.html
[`x86::_bittestandcomplement`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittestandcomplement.html
[`x86::_bittestandreset`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittestandreset.html
[`x86::_bittestandset`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittestandset.html
[`x86_64::_bittest64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittest64.html
[`x86_64::_bittestandcomplement64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandcomplement64.html
[`x86_64::_bittestandreset64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandreset64.html
[`x86_64::_bittestandset64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandset64.html
Version 1.54.0 (2021-07-29)
============================
Language
-----------------------
- [You can now use macros for values in some built-in attributes.][83366]
This primarily allows you to call macros within the `#[doc]` attribute. For
example, to include external documentation in your crate, you can now write
the following:
```rust
#![doc = include_str!("README.md")]
```
- [You can now cast between unsized slice types (and types which contain
unsized slices) in `const fn`.][85078]
- [You can now use multiple generic lifetimes with `impl Trait` where the
lifetimes don't explicitly outlive another.][84701] In code this means
that you can now have `impl Trait<'a, 'b>` where as before you could
only have `impl Trait<'a, 'b> where 'b: 'a`.
Compiler
-----------------------
- [Rustc will now search for custom JSON targets in
`/lib/rustlib/<target-triple>/target.json` where `/` is the "sysroot"
directory.][83800] You can find your sysroot directory by running
`rustc --print sysroot`.
- [Added `wasm` as a `target_family` for WebAssembly platforms.][84072]
- [You can now use `#[target_feature]` on safe functions when targeting
WebAssembly platforms.][84988]
- [Improved debugger output for enums on Windows MSVC platforms.][85292]
- [Added tier 3\* support for `bpfel-unknown-none`
and `bpfeb-unknown-none`.][79608]
- [`-Zmutable-noalias=yes`][82834] is enabled by default when using LLVM 12 or above.
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
-----------------------
- [`panic::panic_any` will now `#[track_caller]`.][85745]
- [Added `OutOfMemory` as a variant of `io::ErrorKind`.][84744]
- [ `proc_macro::Literal` now implements `FromStr`.][84717]
- [The implementations of vendor intrinsics in core::arch have been
significantly refactored.][83278] The main user-visible changes are
a 50% reduction in the size of libcore.rlib and stricter validation
of constant operands passed to intrinsics. The latter is technically
a breaking change, but allows Rust to more closely match the C vendor
intrinsics API.
Stabilized APIs
---------------
- [`BTreeMap::into_keys`]
- [`BTreeMap::into_values`]
- [`HashMap::into_keys`]
- [`HashMap::into_values`]
- [`arch::wasm32`]
- [`VecDeque::binary_search`]
- [`VecDeque::binary_search_by`]
- [`VecDeque::binary_search_by_key`]
- [`VecDeque::partition_point`]
Cargo
-----
- [Added the `--prune <spec>` option to `cargo-tree` to remove a package from
the dependency graph.][cargo/9520]
- [Added the `--depth` option to `cargo-tree` to print only to a certain depth
in the tree ][cargo/9499]
- [Added the `no-proc-macro` value to `cargo-tree --edges` to hide procedural
macro dependencies.][cargo/9488]
- [A new environment variable named `CARGO_TARGET_TMPDIR` is available.][cargo/9375]
This variable points to a directory that integration tests and benches
can use as a "scratchpad" for testing filesystem operations.
Compatibility Notes
-------------------
- [Mixing Option and Result via `?` is no longer permitted in closures for inferred types.][86831]
- [Previously unsound code is no longer permitted where different constructors in branches
could require different lifetimes.][85574]
- As previously mentioned the [`std::arch` instrinsics now uses stricter const checking][83278]
than before and may reject some previously accepted code.
- [`i128` multiplication on Cortex M0+ platforms currently unconditionally causes overflow
when compiled with `codegen-units = 1`.][86063]
[85574]: https://github.com/rust-lang/rust/issues/85574
[86831]: https://github.com/rust-lang/rust/issues/86831
[86063]: https://github.com/rust-lang/rust/issues/86063
[79608]: https://github.com/rust-lang/rust/pull/79608
[84988]: https://github.com/rust-lang/rust/pull/84988
[84701]: https://github.com/rust-lang/rust/pull/84701
[84072]: https://github.com/rust-lang/rust/pull/84072
[85745]: https://github.com/rust-lang/rust/pull/85745
[84744]: https://github.com/rust-lang/rust/pull/84744
[85078]: https://github.com/rust-lang/rust/pull/85078
[84717]: https://github.com/rust-lang/rust/pull/84717
[83800]: https://github.com/rust-lang/rust/pull/83800
[83366]: https://github.com/rust-lang/rust/pull/83366
[83278]: https://github.com/rust-lang/rust/pull/83278
[85292]: https://github.com/rust-lang/rust/pull/85292
[82834]: https://github.com/rust-lang/rust/pull/82834
[cargo/9520]: https://github.com/rust-lang/cargo/pull/9520
[cargo/9499]: https://github.com/rust-lang/cargo/pull/9499
[cargo/9488]: https://github.com/rust-lang/cargo/pull/9488
[cargo/9375]: https://github.com/rust-lang/cargo/pull/9375
[`BTreeMap::into_keys`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.into_keys
[`BTreeMap::into_values`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.into_values
[`HashMap::into_keys`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.into_keys
[`HashMap::into_values`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.into_values
[`arch::wasm32`]: https://doc.rust-lang.org/core/arch/wasm32/index.html
[`VecDeque::binary_search`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.binary_search
[`VecDeque::binary_search_by`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.binary_search_by
[`VecDeque::binary_search_by_key`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.binary_search_by_key
[`VecDeque::partition_point`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.partition_point
Version 1.53.0 (2021-06-17)
============================
Language
-----------------------
- [You can now use unicode for identifiers.][83799] This allows multilingual
identifiers but still doesn't allow glyphs that are not considered characters
such as `◆` or `🦀`. More specifically you can now use any identifier that
matches the UAX #31 "Unicode Identifier and Pattern Syntax" standard. This
is the same standard as languages like Python, however Rust uses NFC
normalization which may be different from other languages.
- [You can now specify "or patterns" inside pattern matches.][79278]
Previously you could only use `|` (OR) on complete patterns. E.g.
```rust
let x = Some(2u8);
// Before
matches!(x, Some(1) | Some(2));
// Now
matches!(x, Some(1 | 2));
```
- [Added the `:pat_param` `macro_rules!` matcher.][83386] This matcher
has the same semantics as the `:pat` matcher. This is to allow `:pat`
to change semantics to being a pattern fragment in a future edition.
Compiler
-----------------------
- [Updated the minimum external LLVM version to LLVM 10.][83387]
- [Added Tier 3\* support for the `wasm64-unknown-unknown` target.][80525]
- [Improved debuginfo for closures and async functions on Windows MSVC.][83941]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
-----------------------
- [Abort messages will now forward to `android_set_abort_message` on
Android platforms when available.][81469]
- [`slice::IterMut<'_, T>` now implements `AsRef<[T]>`][82771]
- [Arrays of any length now implement `IntoIterator`.][84147]
Currently calling `.into_iter()` as a method on an array will
return `impl Iterator<Item=&T>`, but this may change in a
future edition to change `Item` to `T`. Calling `IntoIterator::into_iter`
directly on arrays will provide `impl Iterator<Item=T>` as expected.
- [`leading_zeros`, and `trailing_zeros` are now available on all
`NonZero` integer types.][84082]
- [`{f32, f64}::from_str` now parse and print special values
(`NaN`, `-0`) according to IEEE 754.][78618]
- [You can now index into slices using `(Bound<usize>, Bound<usize>)`.][77704]
- [Add the `BITS` associated constant to all numeric types.][82565]
Stabilised APIs
---------------
- [`AtomicBool::fetch_update`]
- [`AtomicPtr::fetch_update`]
- [`BTreeMap::retain`]
- [`BTreeSet::retain`]
- [`BufReader::seek_relative`]
- [`DebugStruct::non_exhaustive`]
- [`Duration::MAX`]
- [`Duration::ZERO`]
- [`Duration::is_zero`]
- [`Duration::saturating_add`]
- [`Duration::saturating_mul`]
- [`Duration::saturating_sub`]
- [`ErrorKind::Unsupported`]
- [`Option::insert`]
- [`Ordering::is_eq`]
- [`Ordering::is_ge`]
- [`Ordering::is_gt`]
- [`Ordering::is_le`]
- [`Ordering::is_lt`]
- [`Ordering::is_ne`]
- [`OsStr::is_ascii`]
- [`OsStr::make_ascii_lowercase`]
- [`OsStr::make_ascii_uppercase`]
- [`OsStr::to_ascii_lowercase`]
- [`OsStr::to_ascii_uppercase`]
- [`Peekable::peek_mut`]
- [`Rc::decrement_strong_count`]
- [`Rc::increment_strong_count`]
- [`Vec::extend_from_within`]
- [`array::from_mut`]
- [`array::from_ref`]
- [`cmp::max_by_key`]
- [`cmp::max_by`]
- [`cmp::min_by_key`]
- [`cmp::min_by`]
- [`f32::is_subnormal`]
- [`f64::is_subnormal`]
Cargo
-----------------------
- [Cargo now supports git repositories where the default `HEAD` branch is not
"master".][cargo/9392] This also includes a switch to the version 3 `Cargo.lock` format
which can handle default branches correctly.
- [macOS targets now default to `unpacked` split-debuginfo.][cargo/9298]
- [The `authors` field is no longer included in `Cargo.toml` for new
projects.][cargo/9282]
Rustdoc
-----------------------
- [Added the `rustdoc::bare_urls` lint that warns when you have URLs
without hyperlinks.][81764]
Compatibility Notes
-------------------
- [Implement token-based handling of attributes during expansion][82608]
- [`Ipv4::from_str` will now reject octal format IP addresses in addition
to rejecting hexadecimal IP addresses.][83652] The octal format can lead
to confusion and potential security vulnerabilities and [is no
longer recommended][ietf6943].
- [The added `BITS` constant may conflict with external definitions.][85667]
In particular, this was known to be a problem in the `lexical-core` crate,
but they have published fixes for semantic versions 0.4 through 0.7. To
update this dependency alone, use `cargo update -p lexical-core`.
- Incremental compilation remains off by default, unless one uses the `RUSTC_FORCE_INCREMENTAL=1` environment variable added in 1.52.1.
Internal Only
-------------
These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc and
related tools.
- [Rework the `std::sys::windows::alloc` implementation.][83065]
- [rustdoc: Don't enter an infer_ctxt in get_blanket_impls for impls that aren't blanket impls.][82864]
- [rustdoc: Only look at blanket impls in `get_blanket_impls`][83681]
- [Rework rustdoc const type][82873]
[85667]: https://github.com/rust-lang/rust/pull/85667
[83386]: https://github.com/rust-lang/rust/pull/83386
[82771]: https://github.com/rust-lang/rust/pull/82771
[84147]: https://github.com/rust-lang/rust/pull/84147
[84082]: https://github.com/rust-lang/rust/pull/84082
[83799]: https://github.com/rust-lang/rust/pull/83799
[83681]: https://github.com/rust-lang/rust/pull/83681
[83652]: https://github.com/rust-lang/rust/pull/83652