Version 1.94.1 (2026-03-26)
===========================
* [Fix `std::thread::spawn` on wasm32-wasip1-threads](https://github.com/rust-lang/rust/pull/153634)
* [Remove new methods added to `std::os::windows::fs::OpenOptionsExt`](https://github.com/rust-lang/rust/pull/153491)
The new methods were unstable, but the trait itself is not sealed and so
cannot be extended with non-default methods.
* [Clippy: fix ICE in `match_same_arms`](https://github.com/rust-lang/rust-clippy/pull/16685)
* [Cargo: update tar to 0.4.45](https://github.com/rust-lang/cargo/pull/16769)
This resolves CVE-2026-33055 and CVE-2026-33056. Users of crates.io are not affected.
See [blog](https://blog.rust-lang.org/2026/03/21/cve-2026-33056/) for more details.
Version 1.94.0 (2026-03-05)
==========================
Language
--------
- [Impls and impl items inherit `dead_code` lint level of the corresponding traits and trait items](https://github.com/rust-lang/rust/pull/144113)
- [Stabilize additional 29 RISC-V target features including large portions of the RVA22U64 / RVA23U64 profiles](https://github.com/rust-lang/rust/pull/145948)
- [Add warn-by-default `unused_visibilities` lint for visibility on `const _` declarations](https://github.com/rust-lang/rust/pull/147136)
- [Update to Unicode 17](https://github.com/rust-lang/rust/pull/148321)
- [Avoid incorrect lifetime errors for closures](https://github.com/rust-lang/rust/pull/148329)
Platform Support
----------------
- [Add `riscv64im-unknown-none-elf` as a tier 3 target](https://github.com/rust-lang/rust/pull/148790)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Relax `T: Ord` bound for some `BinaryHeap` methods.](https://github.com/rust-lang/rust/pull/149408)
Stabilized APIs
---------------
- [`<[T]>::array_windows`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.array_windows)
- [`<[T]>::element_offset`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.element_offset)
- [`LazyCell::get`](https://doc.rust-lang.org/stable/std/cell/struct.LazyCell.html#method.get)
- [`LazyCell::get_mut`](https://doc.rust-lang.org/stable/std/cell/struct.LazyCell.html#method.get_mut)
- [`LazyCell::force_mut`](https://doc.rust-lang.org/stable/std/cell/struct.LazyCell.html#method.force_mut)
- [`LazyLock::get`](https://doc.rust-lang.org/stable/std/sync/struct.LazyLock.html#method.get)
- [`LazyLock::get_mut`](https://doc.rust-lang.org/stable/std/sync/struct.LazyLock.html#method.get_mut)
- [`LazyLock::force_mut`](https://doc.rust-lang.org/stable/std/sync/struct.LazyLock.html#method.force_mut)
- [`impl TryFrom for usize`](https://doc.rust-lang.org/stable/std/convert/trait.TryFrom.html#impl-TryFrom%3Cchar%3E-for-usize)
- [`std::iter::Peekable::next_if_map`](https://doc.rust-lang.org/stable/std/iter/struct.Peekable.html#method.next_if_map)
- [`std::iter::Peekable::next_if_map_mut`](https://doc.rust-lang.org/stable/std/iter/struct.Peekable.html#method.next_if_map_mut)
- [x86 `avx512fp16` intrinsics](https://github.com/rust-lang/rust/issues/127213)
(excluding those that depend directly on the unstable `f16` type)
- [AArch64 NEON fp16 intrinsics](https://github.com/rust-lang/rust/issues/136306)
(excluding those that depend directly on the unstable `f16` type)
- [`f32::consts::EULER_GAMMA`](https://doc.rust-lang.org/stable/std/f32/consts/constant.EULER_GAMMA.html)
- [`f64::consts::EULER_GAMMA`](https://doc.rust-lang.org/stable/std/f64/consts/constant.EULER_GAMMA.html)
- [`f32::consts::GOLDEN_RATIO`](https://doc.rust-lang.org/stable/std/f32/consts/constant.GOLDEN_RATIO.html)
- [`f64::consts::GOLDEN_RATIO`](https://doc.rust-lang.org/stable/std/f64/consts/constant.GOLDEN_RATIO.html)
These previously stable APIs are now stable in const contexts:
- [`f32::mul_add`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.mul_add)
- [`f64::mul_add`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.mul_add)
Cargo
-----
- Stabilize the config include key. The top-level include config key allows loading additional config files, enabling better organization, sharing, and management of Cargo configurations across projects and environments. [docs](https://doc.rust-lang.org/nightly/cargo/reference/config.html#including-extra-configuration-files) [#16284](https://github.com/rust-lang/cargo/pull/16284)
- Stabilize the pubtime field in registry index. This records when a crate version was published and enables time-based dependency resolution in the future. Note that crates.io will gradually backfill existing packages when a new version is published. Not all crates have pubtime yet. [#16369](https://github.com/rust-lang/cargo/pull/16369) [#16372](https://github.com/rust-lang/cargo/pull/16372)
- Cargo now parses [TOML v1.1](https://toml.io/en/v1.1.0) for manifests and configuration files. Note that using these features in Cargo.toml will raise your development MSRV, but the published manifest remains compatible with older parsers. [#16415](https://github.com/rust-lang/cargo/pull/16415)
- [Make `CARGO_BIN_EXE_` available at runtime ](https://github.com/rust-lang/cargo/pull/16421/)
Compatibility Notes
-------------------
- [Forbid freely casting lifetime bounds of `dyn`-types](https://github.com/rust-lang/rust/pull/136776)
- [Make closure capturing have consistent and correct behaviour around patterns](https://github.com/rust-lang/rust/pull/138961)
Some finer details of how precise closure captures get affected by pattern matching have been changed. In some cases, this can cause a non-move closure that was previously capturing an entire variable by move, to now capture only part of that variable by move, and other parts by borrow. This can cause the borrow checker to complain where it previously didn't, or cause `Drop` to run at a different point in time.
- [Standard library macros are now imported via prelude, not via injected `#[macro_use]`](https://github.com/rust-lang/rust/pull/139493)
This will raise an error if macros of the same name are glob imported.
For example if a crate defines their own `matches` macro and then glob imports that,
it's now ambiguous whether the custom or standard library `matches` is meant and
an explicit import of the name is required to resolve the ambiguity.
One exception is `core::panic` and `std::panic`, if their import is ambiguous
a new warning ([`ambiguous_panic_imports`](https://github.com/rust-lang/rust/issues/147319)) is raised.
This may raise a new warning ([`ambiguous_panic_imports`](https://github.com/rust-lang/rust/issues/147319)) on `#![no_std]` code glob importing the std crate.
Both `core::panic!` and `std::panic!` are then in scope and which is used is ambiguous.
- [Don't strip shebang in expression-context `include!(…)`s](https://github.com/rust-lang/rust/pull/146377)
This can cause previously working includes to no longer compile if they included files which started with a shebang.
- [Ambiguous glob reexports are now also visible cross-crate](https://github.com/rust-lang/rust/pull/147984)
This unifies behavior between local and cross-crate errors on these exports, which may introduce new ambiguity errors.
- [Don't normalize where-clauses before checking well-formedness](https://github.com/rust-lang/rust/pull/148477)
- [Introduce a future compatibility warning on codegen attributes on body-free trait methods](https://github.com/rust-lang/rust/pull/148756)
These attributes currently have no effect in this position.
- [On Windows `std::time::SystemTime::checked_sub_duration` will return `None` for times before the Windows epoch (1/1/1601)](https://github.com/rust-lang/rust/pull/148825)
- [Lifetime identifiers such as `'a` are now NFC normalized](https://github.com/rust-lang/rust/pull/149192).
- [Overhaul filename handling for cross-compiler consistency](https://github.com/rust-lang/rust/pull/149709)
Any paths emitted by compiler now always respect the relative-ness of the paths and `--remap-path-prefix` given originally.
One side-effect of this change is that paths emitted for local crates in Cargo (path dependencies and workspace members) are no longer absolute but relative when emitted as part of a diagnostic in a downstream crate.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Switch to `annotate-snippets` for error emission](https://github.com/rust-lang/rust/pull/150032)
This should preserve mostly the same outputs in rustc error messages.
Version 1.93.1 (2026-02-12)
===========================
- [Don't try to recover keyword as non-keyword identifier](https://github.com/rust-lang/rust/pull/150590), fixing an ICE that especially [affected rustfmt](https://github.com/rust-lang/rustfmt/issues/6739).
- [Fix `clippy::panicking_unwrap` false-positive on field access with implicit deref](https://github.com/rust-lang/rust-clippy/pull/16196).
- [Revert "Update wasm-related dependencies in CI"](https://github.com/rust-lang/rust/pull/152259), fixing file descriptor leaks on the `wasm32-wasip2` target.
Version 1.93.0 (2026-01-22)
==========================
Language
--------
- [Stabilize several s390x `vector`-related target features and the `is_s390x_feature_detected!` macro](https://github.com/rust-lang/rust/pull/145656)
- [Stabilize declaration of C-style variadic functions for the `system` ABI](https://github.com/rust-lang/rust/pull/145954)
- [Emit error when using some keyword as a `cfg` predicate](https://github.com/rust-lang/rust/pull/146978)
- [Stabilize `asm_cfg`](https://github.com/rust-lang/rust/pull/147736)
- [During const-evaluation, support copying pointers byte-by-byte](https://github.com/rust-lang/rust/pull/148259)
- [LUB coercions now correctly handle function item types, and functions with differing safeties](https://github.com/rust-lang/rust/pull/148602)
- [Allow `const` items that contain mutable references to `static` (which is *very* unsafe, but not *always* UB)](https://github.com/rust-lang/rust/pull/148746)
- [Add warn-by-default `const_item_interior_mutations` lint to warn against calls which mutate interior mutable `const` items](https://github.com/rust-lang/rust/pull/148407)
- [Add warn-by-default `function_casts_as_integer` lint](https://github.com/rust-lang/rust/pull/141470)
Compiler
--------
- [Stabilize `-Cjump-tables=bool`](https://github.com/rust-lang/rust/pull/145974). The flag was previously called `-Zno-jump-tables`.
Platform Support
----------------
- [Promote `riscv64a23-unknown-linux-gnu` to Tier 2 (without host tools)](https://github.com/rust-lang/rust/pull/148435)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Stop internally using `specialization` on the `Copy` trait as it is unsound in the presence of lifetime dependent `Copy` implementations. This may result in some performance regressions as some standard library APIs may now call `Clone::clone` instead of performing bitwise copies](https://github.com/rust-lang/rust/pull/135634)
- [Allow the global allocator to use thread-local storage and `std::thread::current()`](https://github.com/rust-lang/rust/pull/144465)
- [Make `BTree::append` not update existing keys when appending an entry which already exists](https://github.com/rust-lang/rust/pull/145628)
- [Don't require `T: RefUnwindSafe` for `vec::IntoIter: UnwindSafe`](https://github.com/rust-lang/rust/pull/145665)
Stabilized APIs
---------------
- [`<[MaybeUninit]>::assume_init_drop`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.assume_init_drop)
- [`<[MaybeUninit]>::assume_init_ref`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.assume_init_ref)
- [`<[MaybeUninit]>::assume_init_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.assume_init_mut)
- [`<[MaybeUninit]>::write_copy_of_slice`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.write_copy_of_slice)
- [`<[MaybeUninit]>::write_clone_of_slice`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.write_clone_of_slice)
- [`String::into_raw_parts`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.into_raw_parts)
- [`Vec::into_raw_parts`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.into_raw_parts)
- [`::unchecked_neg`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_neg)
- [`::unchecked_shl`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_shl)
- [`::unchecked_shr`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unchecked_shr)
- [`::unchecked_shl`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unchecked_shl)
- [`::unchecked_shr`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unchecked_shr)
- [`<[T]>::as_array`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_array)
- [`<[T]>::as_mut_array`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_array)
- [`<*const [T]>::as_array`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_array)
- [`<*mut [T]>::as_mut_array`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_mut_array)
- [`VecDeque::pop_front_if`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.pop_front_if)
- [`VecDeque::pop_back_if`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.pop_back_if)
- [`Duration::from_nanos_u128`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_nanos_u128)
- [`char::MAX_LEN_UTF8`](https://doc.rust-lang.org/stable/std/primitive.char.html#associatedconstant.MAX_LEN_UTF8)
- [`char::MAX_LEN_UTF16`](https://doc.rust-lang.org/stable/std/primitive.char.html#associatedconstant.MAX_LEN_UTF16)
- [`std::fmt::from_fn`](https://doc.rust-lang.org/stable/std/fmt/fn.from_fn.html)
- [`std::fmt::FromFn`](https://doc.rust-lang.org/stable/std/fmt/struct.FromFn.html)
Cargo
-----
- [Enable CARGO_CFG_DEBUG_ASSERTIONS in build scripts based on profile](https://github.com/rust-lang/cargo/pull/16160/)
- [In `cargo tree`, support long forms for `--format` variables](https://github.com/rust-lang/cargo/pull/16204/)
- [Add `--workspace` to `cargo clean`](https://github.com/rust-lang/cargo/pull/16263/)
Rustdoc
-----
- [Remove `#![doc(document_private_items)]`](https://github.com/rust-lang/rust/pull/146495)
- [Include attribute and derive macros in search filters for "macros"](https://github.com/rust-lang/rust/pull/148176)
- [Include extern crates in search filters for `import`](https://github.com/rust-lang/rust/pull/148301)
- [Validate usage of crate-level doc attributes](https://github.com/rust-lang/rust/pull/149197). This means if any of `html_favicon_url`, `html_logo_url`, `html_playground_url`, `issue_tracker_base_url`, or `html_no_source` either has a missing value, an unexpected value, or a value of the wrong type, rustdoc will emit the deny-by-default lint `rustdoc::invalid_doc_attributes`.
Compatibility Notes
-------------------
- [Introduce `pin_v2` into the builtin attributes namespace](https://github.com/rust-lang/rust/pull/139751)
- [Update bundled musl to 1.2.5](https://github.com/rust-lang/rust/pull/142682)
- [On Emscripten, the unwinding ABI used when compiling with `panic=unwind` was changed from the JS exception handling ABI to the wasm exception handling ABI.](https://github.com/rust-lang/rust/pull/147224) If linking C/C++ object files with Rust objects, `-fwasm-exceptions` must be passed to the linker now. On nightly Rust, it is possible to get the old behavior with `-Zwasm-emscripten-eh=false -Zbuild-std`, but it will be removed in a future release.
- The `#[test]` attribute, used to define tests, was previously ignored in various places where it had no meaning (e.g on trait methods or types). Putting the `#[test]` attribute in these places is no longer ignored, and will now result in an error; this may also result in errors when generating rustdoc. [Error when `test` attribute is applied to structs](https://github.com/rust-lang/rust/pull/147841)
- Cargo now sets the `CARGO_CFG_DEBUG_ASSERTIONS` environment variable in more situations. This will cause crates depending on `static-init` versions 1.0.1 to 1.0.3 to fail compilation with "failed to resolve: use of unresolved module or unlinked crate `parking_lot`". See [the linked issue](https://github.com/rust-lang/rust/issues/150646#issuecomment-3718964342) for details.
- [User written types in the `offset_of!` macro are now checked to be well formed.](https://github.com/rust-lang/rust/issues/150465/)
- `cargo publish` no longer emits `.crate` files as a final artifact for user access when the `build.build-dir` config is unset
- [Upgrade the `deref_nullptr` lint from warn-by-default to deny-by-default](https://github.com/rust-lang/rust/pull/148122)
- [Add future-incompatibility warning for `...` function parameters without a pattern outside of `extern` blocks](https://github.com/rust-lang/rust/pull/143619)
- [Introduce future-compatibility warning for `repr(C)` enums whose discriminant values do not fit into a `c_int` or `c_uint`](https://github.com/rust-lang/rust/pull/147017)
- [Introduce future-compatibility warning against ignoring `repr(C)` types as part of `repr(transparent)`](https://github.com/rust-lang/rust/pull/147185)
Version 1.92.0 (2025-12-11)
==========================
Language
--------
- [Document `MaybeUninit` representation and validity](https://github.com/rust-lang/rust/pull/140463)
- [Allow `&raw [mut | const]` for union field in safe code](https://github.com/rust-lang/rust/pull/141469)
- [Prefer item bounds of associated types over where-bounds for auto-traits and `Sized`](https://github.com/rust-lang/rust/pull/144064)
- [Do not materialize `X` in `[X; 0]` when `X` is unsizing a const](https://github.com/rust-lang/rust/pull/145277)
- [Support combining `#[track_caller]` and `#[no_mangle]` (requires every declaration specifying `#[track_caller]` as well)](https://github.com/rust-lang/rust/pull/145724)
- [Make never type lints `never_type_fallback_flowing_into_unsafe` and `dependency_on_unit_never_type_fallback` deny-by-default](https://github.com/rust-lang/rust/pull/146167)
- [Allow specifying multiple bounds for same associated item, except in trait objects](https://github.com/rust-lang/rust/pull/146593)
- [Slightly strengthen higher-ranked region handling in coherence](https://github.com/rust-lang/rust/pull/146725)
- [The `unused_must_use` lint no longer warns on `Result<(), Uninhabited>` (for instance, `Result<(), !>`), or `ControlFlow`](https://github.com/rust-lang/rust/pull/147382). This avoids having to check for an error that can never happen.
Compiler
--------
- [Make `mips64el-unknown-linux-muslabi64` link dynamically](https://github.com/rust-lang/rust/pull/146858)
- [Remove current code for embedding command-line args in PDB](https://github.com/rust-lang/rust/pull/147022)
Command-line information is typically not needed by debugging tools, and the removed code
was causing problems for incremental builds even on targets that don't use PDB debuginfo.
Libraries
---------
- [Specialize `Iterator::eq{_by}` for `TrustedLen` iterators](https://github.com/rust-lang/rust/pull/137122)
- [Simplify `Extend` for tuples](https://github.com/rust-lang/rust/pull/138799)
- [Added details to `Debug` for `EncodeWide`](https://github.com/rust-lang/rust/pull/140153).
- [`iter::Repeat::last`](https://github.com/rust-lang/rust/pull/147258) and [`count`](https://github.com/rust-lang/rust/pull/146410) will now panic, rather than looping infinitely.
Stabilized APIs
---------------
- [`NonZero::div_ceil`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.div_ceil)
- [`Location::file_as_c_str`](https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.file_as_c_str)
- [`RwLockWriteGuard::downgrade`](https://doc.rust-lang.org/stable/std/sync/struct.RwLockWriteGuard.html#method.downgrade)
- [`Box::new_zeroed`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.new_zeroed)
- [`Box::new_zeroed_slice`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.new_zeroed_slice)
- [`Rc::new_zeroed`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.new_zeroed)
- [`Rc::new_zeroed_slice`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.new_zeroed_slice)
- [`Arc::new_zeroed`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.new_zeroed)
- [`Arc::new_zeroed_slice`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.new_zeroed_slice)
- [`btree_map::Entry::insert_entry`](https://doc.rust-lang.org/stable/std/collections/btree_map/enum.Entry.html#method.insert_entry)
- [`btree_map::VacantEntry::insert_entry`](https://doc.rust-lang.org/stable/std/collections/btree_map/struct.VacantEntry.html#method.insert_entry)
- [`impl Extend for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CGroup%3E-for-TokenStream)
- [`impl Extend for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CLiteral%3E-for-TokenStream)
- [`impl Extend for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CPunct%3E-for-TokenStream)
- [`impl Extend for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CIdent%3E-for-TokenStream)
These previously stable APIs are now stable in const contexts:
- [`<[_]>::rotate_left`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.rotate_left)
- [`<[_]>::rotate_right`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.rotate_right)
Cargo
-----
- [Added a new chapter](https://github.com/rust-lang/cargo/issues/16119) to the Cargo book, ["Optimizing Build Performance"](https://doc.rust-lang.org/stable/cargo/guide/build-performance.html).
Rustdoc
-----
- [If a trait item appears in rustdoc search, hide the corresponding impl items](https://github.com/rust-lang/rust/pull/145898). Previously a search for "last" would show both `Iterator::last` as well as impl methods like `std::vec::IntoIter::last`. Now these impl methods will be hidden, freeing up space for inherent methods like `BTreeSet::last`.
- [Relax rules for identifiers in search](https://github.com/rust-lang/rust/pull/147860). Previously you could only search for identifiers that were valid in rust code, now searches only need to be valid as part of an identifier. For example, you can now perform a search that starts with a digit.
Compatibility Notes
-------------------
* [Fix backtraces with `-C panic=abort` on Linux by generating unwind tables by default](https://github.com/rust-lang/rust/pull/143613). Build with `-C force-unwind-tables=no` to keep omitting unwind tables.
- As part of the larger effort refactoring compiler built-in attributes and their diagnostics, [the future-compatibility lint `invalid_macro_export_arguments` is upgraded to deny-by-default and will be reported in dependencies too.](https://github.com/rust-lang/rust/pull/143857)
- [Update the minimum external LLVM to 20](https://github.com/rust-lang/rust/pull/145071)
- [Prevent downstream `impl DerefMut for Pin`](https://github.com/rust-lang/rust/pull/145608)
- [Don't apply temporary lifetime extension rules to the arguments of non-extended `pin!` and formatting macros](https://github.com/rust-lang/rust/pull/145838)
Version 1.91.1 (2025-11-10)
===========================
- [Enable file locking support in illumos](https://github.com/rust-lang/rust/pull/148322). This fixes Cargo not locking the build directory on illumos.
- [Fix `wasm_import_module` attribute cross-crate](https://github.com/rust-lang/rust/pull/148363). This fixes linker errors on WASM targets.
Version 1.91.0 (2025-10-30)
==========================
Language
--------
- [Lower pattern bindings in the order they're written and base drop order on primary bindings' order](https://github.com/rust-lang/rust/pull/143764)
- [Stabilize declaration of C-style variadic functions for `sysv64`, `win64`, `efiapi`, and `aapcs` ABIs](https://github.com/rust-lang/rust/pull/144066).
This brings these ABIs in line with the C ABI: variadic functions can be declared in extern blocks but not defined.
- [Add `dangling_pointers_from_locals` lint to warn against dangling pointers from local variables](https://github.com/rust-lang/rust/pull/144322)
- [Upgrade `semicolon_in_expressions_from_macros` from warn to deny](https://github.com/rust-lang/rust/pull/144369)
- [Stabilize LoongArch32 inline assembly](https://github.com/rust-lang/rust/pull/144402)
- [Add warn-by-default `integer_to_ptr_transmutes` lint against integer-to-pointer transmutes](https://github.com/rust-lang/rust/pull/144531)
- [Stabilize `sse4a` and `tbm` target features](https://github.com/rust-lang/rust/pull/144542)
- [Add `target_env = "macabi"` and `target_env = "sim"` cfgs](https://github.com/rust-lang/rust/pull/139451) as replacements for the `target_abi` cfgs with the same values.
Compiler
--------
- [Don't warn on never-to-any `as` casts as unreachable](https://github.com/rust-lang/rust/pull/144804)
Platform Support
----------------
- [Promote `aarch64-pc-windows-gnullvm` and `x86_64-pc-windows-gnullvm` to Tier 2 with host tools.](https://github.com/rust-lang/rust/pull/143031)
Note: llvm-tools and MSI installers are missing but will be added in future releases.
- [Promote `aarch64-pc-windows-msvc` to Tier 1](https://github.com/rust-lang/rust/pull/145682)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Print thread ID in panic message](https://github.com/rust-lang/rust/pull/115746)
- [Fix overly restrictive lifetime in `core::panic::Location::file` return type](https://github.com/rust-lang/rust/pull/132087)
- [Guarantee parameter order for `_by()` variants of `min` / `max`/ `minmax` in `std::cmp`](https://github.com/rust-lang/rust/pull/139357)
- [Document assumptions about `Clone` and `Eq` traits](https://github.com/rust-lang/rust/pull/144330/)
- [`std::thread`: Return error if setting thread stack size fails](https://github.com/rust-lang/rust/pull/144210)
This used to panic within the standard library.
Stabilized APIs
---------------
- [`Path::file_prefix`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.file_prefix)
- [`AtomicPtr::fetch_ptr_add`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_ptr_add)
- [`AtomicPtr::fetch_ptr_sub`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_ptr_sub)
- [`AtomicPtr::fetch_byte_add`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_byte_add)
- [`AtomicPtr::fetch_byte_sub`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_byte_sub)
- [`AtomicPtr::fetch_or`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_or)
- [`AtomicPtr::fetch_and`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_and)
- [`AtomicPtr::fetch_xor`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_xor)
- [`{integer}::strict_add`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_add)
- [`{integer}::strict_sub`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_sub)
- [`{integer}::strict_mul`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_mul)
- [`{integer}::strict_div`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_div)
- [`{integer}::strict_div_euclid`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_div_euclid)
- [`{integer}::strict_rem`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_rem)
- [`{integer}::strict_rem_euclid`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_rem_euclid)
- [`{integer}::strict_neg`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_neg)
- [`{integer}::strict_shl`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_shl)
- [`{integer}::strict_shr`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_shr)
- [`{integer}::strict_pow`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_pow)
- [`i{N}::strict_add_unsigned`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_add_unsigned)
- [`i{N}::strict_sub_unsigned`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_sub_unsigned)
- [`i{N}::strict_abs`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_abs)
- [`u{N}::strict_add_signed`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_add_signed)
- [`u{N}::strict_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_sub_signed)
- [`PanicHookInfo::payload_as_str`](https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html#method.payload_as_str)
- [`core::iter::chain`](https://doc.rust-lang.org/stable/core/iter/fn.chain.html)
- [`u{N}::checked_signed_diff`](https://doc.rust-lang.org/stable/std/primitive.u16.html#method.checked_signed_diff)
- [`core::array::repeat`](https://doc.rust-lang.org/stable/core/array/fn.repeat.html)
- [`PathBuf::add_extension`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.add_extension)
- [`PathBuf::with_added_extension`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.with_added_extension)
- [`Duration::from_mins`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_mins)
- [`Duration::from_hours`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_hours)
- [`impl PartialEq for PathBuf`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-PartialEq%3Cstr%3E-for-PathBuf)
- [`impl PartialEq for PathBuf`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-PartialEq%3CString%3E-for-PathBuf)
- [`impl PartialEq for Path`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#impl-PartialEq%3Cstr%3E-for-Path)
- [`impl PartialEq for Path`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#impl-PartialEq%3CString%3E-for-Path)
- [`impl PartialEq for String`](https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-PartialEq%3CPathBuf%3E-for-String)
- [`impl PartialEq for String`](https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-PartialEq%3CPath%3E-for-String)
- [`impl PartialEq for str`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-PartialEq%3CPathBuf%3E-for-str)
- [`impl PartialEq for str`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-PartialEq%3CPath%3E-for-str)
- [`Ipv4Addr::from_octets`](https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.from_octets)
- [`Ipv6Addr::from_octets`](https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.from_octets)
- [`Ipv6Addr::from_segments`](https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.from_segments)
- [`impl Default for Pin> where Box: Default, T: ?Sized`](https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CBox%3CT%3E%3E)
- [`impl Default for Pin> where Rc: Default, T: ?Sized`](https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CRc%3CT%3E%3E)
- [`impl Default for Pin> where Arc: Default, T: ?Sized`](https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CArc%3CT%3E%3E)
- [`Cell::as_array_of_cells`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.as_array_of_cells)
- [`u{N}::carrying_add`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_add)
- [`u{N}::borrowing_sub`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.borrowing_sub)
- [`u{N}::carrying_mul`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_mul)
- [`u{N}::carrying_mul_add`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_mul_add)
- [`BTreeMap::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.extract_if)
- [`BTreeSet::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.extract_if)
- [`impl Debug for windows::ffi::EncodeWide<'_>`](https://doc.rust-lang.org/stable/std/os/windows/ffi/struct.EncodeWide.html#impl-Debug-for-EncodeWide%3C'_%3E)
- [`str::ceil_char_boundary`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.ceil_char_boundary)
- [`str::floor_char_boundary`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.floor_char_boundary)
- [`impl Sum for Saturating`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Sum-for-Saturating%3Cu32%3E)
- [`impl Sum<&Self> for Saturating`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Sum%3C%26Saturating%3Cu32%3E%3E-for-Saturating%3Cu32%3E)
- [`impl Product for Saturating`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Product-for-Saturating%3Cu32%3E)
- [`impl Product<&Self> for Saturating`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Product%3C%26Saturating%3Cu32%3E%3E-for-Saturating%3Cu32%3E)
These previously stable APIs are now stable in const contexts:
- [`<[T; N]>::each_ref`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_ref)
- [`<[T; N]>::each_mut`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_mut)
- [`OsString::new`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.new)
- [`PathBuf::new`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.new)
- [`TypeId::of`](https://doc.rust-lang.org/stable/std/any/struct.TypeId.html#method.of)
- [`ptr::with_exposed_provenance`](https://doc.rust-lang.org/stable/std/ptr/fn.with_exposed_provenance.html)
- [`ptr::with_exposed_provenance_mut`](https://doc.rust-lang.org/stable/std/ptr/fn.with_exposed_provenance_mut.html)
Cargo
-----
- 🎉 Stabilize `build.build-dir`.
This config sets the directory where intermediate build artifacts are stored.
These artifacts are produced by Cargo and rustc during the build process.
End users usually won't need to interact with them, and the layout inside
`build-dir` is an implementation detail that may change without notice.
([config doc](https://doc.rust-lang.org/stable/cargo/reference/config.html#buildbuild-dir))
([build cache doc](https://doc.rust-lang.org/stable/cargo/reference/build-cache.html))
[#15833](https://github.com/rust-lang/cargo/pull/15833)
[#15840](https://github.com/rust-lang/cargo/pull/15840)
- The `--target` flag and the `build.target` configuration can now take literal
`"host-tuple"` string, which will internally be substituted by the host
machine's target triple.
[#15838](https://github.com/rust-lang/cargo/pull/15838)
[#16003](https://github.com/rust-lang/cargo/pull/16003)
[#16032](https://github.com/rust-lang/cargo/pull/16032)
Rustdoc
-----
- [In search results, rank doc aliases lower than non-alias items with the same name](https://github.com/rust-lang/rust/pull/145100)
- [Raw pointers now work in type-based search like references](https://github.com/rust-lang/rust/pull/145731). This means you can now search for things like `*const u8 ->`, and additionally functions that take or return raw pointers will now display their signature properly in search results.
Compatibility Notes
-------------------
- [Always require coroutine captures to be drop-live](https://github.com/rust-lang/rust/pull/144156)
- [Apple: Always pass SDK root when linking with `cc`, and pass it via `SDKROOT` env var](https://github.com/rust-lang/rust/pull/131477). This should fix linking issues with `rustc` running inside Xcode. Libraries in `/usr/local/lib` may no longer be linked automatically, if you develop or use a crate that relies on this, you should explicitly set `cargo::rustc-link-search=/usr/local/lib` in a `build.rs` script.
- [Relaxed bounds in associated type bound position like in `TraitRef` are now correctly forbidden](https://github.com/rust-lang/rust/pull/135331)
- [Add unstable `#[sanitize(xyz = "on|off")]` built-in attribute that shadows procedural macros with the same name](https://github.com/rust-lang/rust/pull/142681)
- [Fix the drop checker being more permissive for bindings declared with let-else](https://github.com/rust-lang/rust/pull/143028)
- [Be more strict when parsing attributes, erroring on many invalid attributes](https://github.com/rust-lang/rust/pull/144689)
- [Error on invalid `#[should_panic]` attributes](https://github.com/rust-lang/rust/pull/143808)
- [Error on invalid `#[link]` attributes](https://github.com/rust-lang/rust/pull/143193)
- [Mark all deprecation lints in name resolution as deny-by-default and also report in dependencies](https://github.com/rust-lang/rust/pull/143929)
- The lint `semicolon_in_expressions_from_macros`, for `macro_rules!` macros in expression position that expand to end in a semicolon (`;`), is now deny-by-default. It was already warn-by-default, and a future compatibility warning (FCW) that warned even in dependencies. This lint will become a hard error in the future.
- [Trait impl modifiers (e.g., `unsafe`, `!`, `default`) in inherent impls are no longer syntactically valid](https://github.com/rust-lang/rust/pull/144386)
- [Start reporting future breakage for `ill_formed_attribute_input` in dependencies](https://github.com/rust-lang/rust/pull/144544)
- [Restrict the scope of temporaries created by the macros `pin!`, `format_args!`, `write!`, and `writeln!` in `if let` scrutinees in Rust Edition 2024.](https://github.com/rust-lang/rust/pull/145342) This applies [Rust Edition 2024's `if let` temporary scope rules](https://doc.rust-lang.org/edition-guide/rust-2024/temporary-if-let-scope.html) to these temporaries, which previously could live past the `if` expression regardless of Edition.
- [Invalid numeric literal suffixes in tuple indexing, tuple struct indexing, and struct field name positions are now correctly rejected](https://github.com/rust-lang/rust/pull/145463)
- [Closures marked with the keyword `static` are now syntactically invalid](https://github.com/rust-lang/rust/pull/145604)
- [Shebangs inside `--cfg` and `--check-cfg` arguments are no longer allowed](https://github.com/rust-lang/rust/pull/146211)
- [Add future incompatibility lint for temporary lifetime shortening in Rust 1.92](https://github.com/rust-lang/rust/pull/147056)
Cargo compatibility notes:
- `cargo publish` no longer keeps `.crate` tarballs as final build artifacts
when `build.build-dir` is set. These tarballs were previously included due to
an oversight and are now treated as intermediate artifacts.
To get `.crate` tarballs as final artifacts, use `cargo package`.
In a future version, this change will apply regardless of `build.build-dir`.
[#15910](https://github.com/rust-lang/cargo/pull/15910)
- Adjust Cargo messages to match rustc diagnostic style.
This changes some of the terminal colors used by Cargo messages.
[#15928](https://github.com/rust-lang/cargo/pull/15928)
- Tools and projects relying on the
[internal details of Cargo's `build-dir`](https://doc.rust-lang.org/cargo/reference/build-cache.html)
may not work for users changing their `build-dir` layout.
For those doing so, we'd recommend proactively testing these cases
particularly as we are considering changing the default location of the `build-dir` in the future
([cargo#16147](https://github.com/rust-lang/cargo/issues/16147)).
If you can't migrate off of Cargo's internal details,
we'd like to learn more about your use case as we prepare to change the layout of the `build-dir`
([cargo#15010](https://github.com/rust-lang/cargo/issues/15010)).
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Update to LLVM 21](https://github.com/rust-lang/rust/pull/143684)
Version 1.90.0 (2025-09-18)
===========================
Language
--------
- [Split up the `unknown_or_malformed_diagnostic_attributes` lint](https://github.com/rust-lang/rust/pull/140717). This lint has been split up into four finer-grained lints, with `unknown_or_malformed_diagnostic_attributes` now being the lint group that contains these lints:
1. `unknown_diagnostic_attributes`: unknown to the current compiler
2. `misplaced_diagnostic_attributes`: placed on the wrong item
3. `malformed_diagnostic_attributes`: malformed attribute syntax or options
4. `malformed_diagnostic_format_literals`: malformed format string literal
- [Allow constants whose final value has references to mutable/external memory, but reject such constants as patterns](https://github.com/rust-lang/rust/pull/140942)
- [Allow volatile access to non-Rust memory, including address 0](https://github.com/rust-lang/rust/pull/141260)
Compiler
--------
- [Use `lld` by default on `x86_64-unknown-linux-gnu`](https://github.com/rust-lang/rust/pull/140525).
- [Tier 3 `musl` targets now link dynamically by default](https://github.com/rust-lang/rust/pull/144410). Affected targets:
- `mips64-unknown-linux-muslabi64`
- `powerpc64-unknown-linux-musl`
- `powerpc-unknown-linux-musl`
- `powerpc-unknown-linux-muslspe`
- `riscv32gc-unknown-linux-musl`
- `s390x-unknown-linux-musl`
- `thumbv7neon-unknown-linux-musleabihf`
Platform Support
----------------
- [Demote `x86_64-apple-darwin` to Tier 2 with host tools](https://github.com/rust-lang/rust/pull/145252)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Stabilize `u*::{checked,overflowing,saturating,wrapping}_sub_signed`](https://github.com/rust-lang/rust/issues/126043)
- [Allow comparisons between `CStr`, `CString`, and `Cow`](https://github.com/rust-lang/rust/pull/137268)
- [Remove some unsized tuple impls since unsized tuples can't be constructed](https://github.com/rust-lang/rust/pull/138340)
- [Set `MSG_NOSIGNAL` for `UnixStream`](https://github.com/rust-lang/rust/pull/140005)
- [`proc_macro::Ident::new` now supports `$crate`.](https://github.com/rust-lang/rust/pull/141996)
- [Guarantee the pointer returned from `Thread::into_raw` has at least 8 bytes of alignment](https://github.com/rust-lang/rust/pull/143859)
Stabilized APIs
---------------
- [`u{n}::checked_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.checked_sub_signed)
- [`u{n}::overflowing_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.overflowing_sub_signed)
- [`u{n}::saturating_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.saturating_sub_signed)
- [`u{n}::wrapping_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.wrapping_sub_signed)
- [`impl Copy for IntErrorKind`](https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Copy-for-IntErrorKind)
- [`impl Hash for IntErrorKind`](https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Hash-for-IntErrorKind)
- [`impl PartialEq<&CStr> for CStr`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3C%26CStr%3E-for-CStr)
- [`impl PartialEq for CStr`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCString%3E-for-CStr)
- [`impl PartialEq> for CStr`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CStr)
- [`impl PartialEq<&CStr> for CString`](https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3C%26CStr%3E-for-CString)
- [`impl PartialEq for CString`](https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCStr%3E-for-CString)
- [`impl PartialEq> for CString`](https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CString)
- [`impl PartialEq<&CStr> for Cow`](https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3C%26CStr%3E-for-Cow%3C'_,+CStr%3E)
- [`impl PartialEq for Cow`](https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCStr%3E-for-Cow%3C'_,+CStr%3E)
- [`impl PartialEq for Cow`](https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCString%3E-for-Cow%3C'_,+CStr%3E)
These previously stable APIs are now stable in const contexts:
- [`<[T]>::reverse`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.reverse)
- [`f32::floor`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.floor)
- [`f32::ceil`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.ceil)
- [`f32::trunc`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.trunc)
- [`f32::fract`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.fract)
- [`f32::round`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round)
- [`f32::round_ties_even`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even)
- [`f64::floor`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.floor)
- [`f64::ceil`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.ceil)
- [`f64::trunc`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.trunc)
- [`f64::fract`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.fract)
- [`f64::round`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round)
- [`f64::round_ties_even`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even)
Cargo
-----
- [Add `http.proxy-cainfo` config for proxy certs](https://github.com/rust-lang/cargo/pull/15374/)
- [Use `gix` for `cargo package`](https://github.com/rust-lang/cargo/pull/15534/)
- [feat(publish): Stabilize multi-package publishing](https://github.com/rust-lang/cargo/pull/15636/)
Rustdoc
-----
- [Add ways to collapse all impl blocks](https://github.com/rust-lang/rust/pull/141663). Previously the "Summary" button and "-" keyboard shortcut would never collapse `impl` blocks, now they do when shift is held
- [Display unsafe attributes with `unsafe()` wrappers](https://github.com/rust-lang/rust/pull/143662)
Compatibility Notes
-------------------
- [Use `lld` by default on `x86_64-unknown-linux-gnu`](https://github.com/rust-lang/rust/pull/140525).
See also .
- [Make `core::iter::Fuse`'s `Default` impl construct `I::default()` internally as promised in the docs instead of always being empty](https://github.com/rust-lang/rust/pull/140985)
- [Set `MSG_NOSIGNAL` for `UnixStream`](https://github.com/rust-lang/rust/pull/140005)
This may change program behavior but results in the same behavior as other primitives (e.g., stdout, network sockets).
Programs relying on signals to terminate them should update handling of sockets to handle errors on write by exiting.
- [On Unix `std::env::home_dir` will use the fallback if the `HOME` environment variable is empty](https://github.com/rust-lang/rust/pull/141840)
- We now [reject unsupported `extern "{abi}"`s consistently in all positions](https://github.com/rust-lang/rust/pull/142134). This primarily affects the use of implementing traits on an `extern "{abi}"` function pointer, like `extern "stdcall" fn()`, on a platform that doesn't support that, like aarch64-unknown-linux-gnu. Direct usage of these unsupported ABI strings by declaring or defining functions was already rejected, so this is only a change for consistency.
- [const-eval: error when initializing a static writes to that static](https://github.com/rust-lang/rust/pull/143084)
- [Check that the `proc_macro_derive` macro has correct arguments when applied to the crate root](https://github.com/rust-lang/rust/pull/143607)
Version 1.89.0 (2025-08-07)
==========================
Language
--------
- [Stabilize explicitly inferred const arguments (`feature(generic_arg_infer)`)](https://github.com/rust-lang/rust/pull/141610)
- [Add a warn-by-default `mismatched_lifetime_syntaxes` lint.](https://github.com/rust-lang/rust/pull/138677)
This lint detects when the same lifetime is referred to by different syntax categories between function arguments and return values, which can be confusing to read, especially in unsafe code.
This lint supersedes the warn-by-default `elided_named_lifetimes` lint.
- [Expand `unpredictable_function_pointer_comparisons` to also lint on function pointer comparisons in external macros](https://github.com/rust-lang/rust/pull/134536)
- [Make the `dangerous_implicit_autorefs` lint deny-by-default](https://github.com/rust-lang/rust/pull/141661)
- [Stabilize the avx512 target features](https://github.com/rust-lang/rust/pull/138940)
- [Stabilize `kl` and `widekl` target features for x86](https://github.com/rust-lang/rust/pull/140766)
- [Stabilize `sha512`, `sm3` and `sm4` target features for x86](https://github.com/rust-lang/rust/pull/140767)
- [Stabilize LoongArch target features `f`, `d`, `frecipe`, `lasx`, `lbt`, `lsx`, and `lvz`](https://github.com/rust-lang/rust/pull/135015)
- [Remove `i128` and `u128` from `improper_ctypes_definitions`](https://github.com/rust-lang/rust/pull/137306)
- [Stabilize `repr128` (`#[repr(u128)]`, `#[repr(i128)]`)](https://github.com/rust-lang/rust/pull/138285)
- [Allow `#![doc(test(attr(..)))]` everywhere](https://github.com/rust-lang/rust/pull/140560)
- [Extend temporary lifetime extension to also go through tuple struct and tuple variant constructors](https://github.com/rust-lang/rust/pull/140593)
- [`extern "C"` functions on the `wasm32-unknown-unknown` target now have a standards compliant ABI](https://blog.rust-lang.org/2025/04/04/c-abi-changes-for-wasm32-unknown-unknown/)
Compiler
--------
- [Default to non-leaf frame pointers on aarch64-linux](https://github.com/rust-lang/rust/pull/140832)
- [Enable non-leaf frame pointers for Arm64EC Windows](https://github.com/rust-lang/rust/pull/140862)
- [Set Apple frame pointers by architecture](https://github.com/rust-lang/rust/pull/141797)
Platform Support
----------------
- [Add new Tier-3 targets `loongarch32-unknown-none` and `loongarch32-unknown-none-softfloat`](https://github.com/rust-lang/rust/pull/142053)
- [`x86_64-apple-darwin` is in the process of being demoted to Tier 2 with host tools](https://github.com/rust-lang/rfcs/pull/3841)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Specify the base path for `file!`](https://github.com/rust-lang/rust/pull/134442)
- [Allow storing `format_args!()` in a variable](https://github.com/rust-lang/rust/pull/140748)
- [Add `#[must_use]` to `[T; N]::map`](https://github.com/rust-lang/rust/pull/140957)
- [Implement `DerefMut` for `Lazy{Cell,Lock}`](https://github.com/rust-lang/rust/pull/129334)
- [Implement `Default` for `array::IntoIter`](https://github.com/rust-lang/rust/pull/141574)
- [Implement `Clone` for `slice::ChunkBy`](https://github.com/rust-lang/rust/pull/138016)
- [Implement `io::Seek` for `io::Take`](https://github.com/rust-lang/rust/pull/138023)
Stabilized APIs
---------------
- [`NonZero`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html)
- Many intrinsics for x86, not enumerated here
- [AVX512 intrinsics](https://github.com/rust-lang/rust/issues/111137)
- [`SHA512`, `SM3` and `SM4` intrinsics](https://github.com/rust-lang/rust/issues/126624)
- [`File::lock`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock)
- [`File::lock_shared`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock_shared)
- [`File::try_lock`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock)
- [`File::try_lock_shared`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock_shared)
- [`File::unlock`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.unlock)
- [`NonNull::from_ref`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_ref)
- [`NonNull::from_mut`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_mut)
- [`NonNull::without_provenance`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.without_provenance)
- [`NonNull::with_exposed_provenance`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.with_exposed_provenance)
- [`NonNull::expose_provenance`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.expose_provenance)
- [`OsString::leak`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.leak)
- [`PathBuf::leak`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.leak)
- [`Result::flatten`](https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.flatten)
- [`std::os::linux::net::TcpStreamExt::quickack`](https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.quickack)
- [`std::os::linux::net::TcpStreamExt::set_quickack`](https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.set_quickack)
These previously stable APIs are now stable in const contexts:
- [`<[T; N]>::as_mut_slice`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.as_mut_slice)
- [`<[u8]>::eq_ignore_ascii_case`](https://doc.rust-lang.org/stable/std/primitive.slice.html#impl-%5Bu8%5D/method.eq_ignore_ascii_case)
- [`str::eq_ignore_ascii_case`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-str/method.eq_ignore_ascii_case)
Cargo
-----
- [`cargo fix` and `cargo clippy --fix` now default to the same Cargo target selection as other build commands.](https://github.com/rust-lang/cargo/pull/15192/) Previously it would apply to all targets (like binaries, examples, tests, etc.). The `--edition` flag still applies to all targets.
- [Stabilize doctest-xcompile.](https://github.com/rust-lang/cargo/pull/15462/) Doctests are now tested when cross-compiling. Just like other tests, it will use the [`runner` setting](https://doc.rust-lang.org/cargo/reference/config.html#targettriplerunner) to run the tests. If you need to disable tests for a target, you can use the [ignore doctest attribute](https://doc.rust-lang.org/rustdoc/write-documentation/documentation-tests.html#ignoring-targets) to specify the targets to ignore.
Rustdoc
-----
- [On mobile, make the sidebar full width and linewrap](https://github.com/rust-lang/rust/pull/139831). This makes long section and item names much easier to deal with on mobile.
Compatibility Notes
-------------------
- [Make `missing_fragment_specifier` an unconditional error](https://github.com/rust-lang/rust/pull/128425)
- [Enabling the `neon` target feature on `aarch64-unknown-none-softfloat` causes a warning](https://github.com/rust-lang/rust/pull/135160) because mixing code with and without that target feature is not properly supported by LLVM
- [Sized Hierarchy: Part I](https://github.com/rust-lang/rust/pull/137944)
- Introduces a small breaking change affecting `?Sized` bounds on impls on recursive types which contain associated type projections. It is not expected to affect any existing published crates. Can be fixed by refactoring the involved types or opting into the `sized_hierarchy` unstable feature. See the [FCP report](https://github.com/rust-lang/rust/pull/137944#issuecomment-2912207485) for a code example.
- The warn-by-default `elided_named_lifetimes` lint is [superseded by the warn-by-default `mismatched_lifetime_syntaxes` lint.](https://github.com/rust-lang/rust/pull/138677)
- [Error on recursive opaque types earlier in the type checker](https://github.com/rust-lang/rust/pull/139419)
- [Type inference side effects from requiring element types of array repeat expressions are `Copy` are now only available at the end of type checking](https://github.com/rust-lang/rust/pull/139635)
- [The deprecated accidentally-stable `std::intrinsics::{copy,copy_nonoverlapping,write_bytes}` are now proper intrinsics](https://github.com/rust-lang/rust/pull/139916). There are no debug assertions guarding against UB, and they cannot be coerced to function pointers.
- [Remove long-deprecated `std::intrinsics::drop_in_place`](https://github.com/rust-lang/rust/pull/140151)
- [Make well-formedness predicates no longer coinductive](https://github.com/rust-lang/rust/pull/140208)
- [Remove hack when checking impl method compatibility](https://github.com/rust-lang/rust/pull/140557)
- [Remove unnecessary type inference due to built-in trait object impls](https://github.com/rust-lang/rust/pull/141352)
- [Lint against "stdcall", "fastcall", and "cdecl" on non-x86-32 targets](https://github.com/rust-lang/rust/pull/141435)
- [Future incompatibility warnings relating to the never type (`!`) are now reported in dependencies](https://github.com/rust-lang/rust/pull/141937)
- [Ensure `std::ptr::copy_*` intrinsics also perform the static self-init checks](https://github.com/rust-lang/rust/pull/142575)
- [`extern "C"` functions on the `wasm32-unknown-unknown` target now have a standards compliant ABI](https://blog.rust-lang.org/2025/04/04/c-abi-changes-for-wasm32-unknown-unknown/)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Correctly un-remap compiler sources paths with the `rustc-dev` component](https://github.com/rust-lang/rust/pull/142377)
Version 1.88.0 (2025-06-26)
==========================
Language
--------
- [Stabilize `#![feature(let_chains)]` in the 2024 edition.](https://github.com/rust-lang/rust/pull/132833)
This feature allows `&&`-chaining `let` statements inside `if` and `while`, allowing intermixture with boolean expressions. The patterns inside the `let` sub-expressions can be irrefutable or refutable.
- [Stabilize `#![feature(naked_functions)]`.](https://github.com/rust-lang/rust/pull/134213)
Naked functions allow writing functions with no compiler-generated epilogue and prologue, allowing full control over the generated assembly for a particular function.
- [Stabilize `#![feature(cfg_boolean_literals)]`.](https://github.com/rust-lang/rust/pull/138632)
This allows using boolean literals as `cfg` predicates, e.g. `#[cfg(true)]` and `#[cfg(false)]`.
- [Fully de-stabilize the `#[bench]` attribute](https://github.com/rust-lang/rust/pull/134273). Usage of `#[bench]` without `#![feature(custom_test_frameworks)]` already triggered a deny-by-default future-incompatibility lint since Rust 1.77, but will now become a hard error.
- [Add warn-by-default `dangerous_implicit_autorefs` lint against implicit autoref of raw pointer dereference.](https://github.com/rust-lang/rust/pull/123239)
The lint [will be bumped to deny-by-default](https://github.com/rust-lang/rust/pull/141661) in the next version of Rust.
- [Add `invalid_null_arguments` lint to prevent invalid usage of null pointers.](https://github.com/rust-lang/rust/pull/119220)
This lint is uplifted from `clippy::invalid_null_ptr_usage`.
- [Change trait impl candidate preference for builtin impls and trivial where-clauses.](https://github.com/rust-lang/rust/pull/138176)
- [Check types of generic const parameter defaults](https://github.com/rust-lang/rust/pull/139646)
Compiler
--------
- [Stabilize `-Cdwarf-version` for selecting the version of DWARF debug information to generate.](https://github.com/rust-lang/rust/pull/136926)
Platform Support
----------------
- [Demote `i686-pc-windows-gnu` to Tier 2.](https://blog.rust-lang.org/2025/05/26/demoting-i686-pc-windows-gnu/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Remove backticks from `#[should_panic]` test failure message.](https://github.com/rust-lang/rust/pull/136160)
- [Guarantee that `[T; N]::from_fn` is generated in order of increasing indices.](https://github.com/rust-lang/rust/pull/139099), for those passing it a stateful closure.
- [The libtest flag `--nocapture` is deprecated in favor of the more consistent `--no-capture` flag.](https://github.com/rust-lang/rust/pull/139224)
- [Guarantee that `{float}::NAN` is a quiet NaN.](https://github.com/rust-lang/rust/pull/139483)
Stabilized APIs
---------------
- [`Cell::update`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.update)
- [`impl Default for *const T`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#impl-Default-for-*const+T)
- [`impl Default for *mut T`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#impl-Default-for-*mut+T)
- [`HashMap::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.HashMap.html#method.extract_if)
- [`HashSet::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.HashSet.html#method.extract_if)
- [`hint::select_unpredictable`](https://doc.rust-lang.org/stable/std/hint/fn.select_unpredictable.html)
- [`proc_macro::Span::line`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.line)
- [`proc_macro::Span::column`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.column)
- [`proc_macro::Span::start`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.start)
- [`proc_macro::Span::end`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.end)
- [`proc_macro::Span::file`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.file)
- [`proc_macro::Span::local_file`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.local_file)
- [`<[T]>::as_chunks`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks)
- [`<[T]>::as_chunks_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks_mut)
- [`<[T]>::as_chunks_unchecked`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks_unchecked)
- [`<[T]>::as_chunks_unchecked_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_chunks_unchecked_mut)
- [`<[T]>::as_rchunks`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_rchunks)
- [`<[T]>::as_rchunks_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_rchunks_mut)
- [`mod ffi::c_str`](https://doc.rust-lang.org/stable/std/ffi/c_str/index.html)
These previously stable APIs are now stable in const contexts:
- [`NonNull::replace`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.replace)
- [`<*mut T>::replace`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.replace)
- [`std::ptr::swap_nonoverlapping`](https://doc.rust-lang.org/stable/std/ptr/fn.swap_nonoverlapping.html)
- [`Cell::replace`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.replace)
- [`Cell::get`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.get)
- [`Cell::get_mut`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.get_mut)
- [`Cell::from_mut`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.from_mut)
- [`Cell::as_slice_of_cells`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.as_slice_of_cells)
Cargo
-----
- [Stabilize automatic garbage collection.](https://github.com/rust-lang/cargo/pull/14287/)
- [use `zlib-rs` for gzip compression in rust code](https://github.com/rust-lang/cargo/pull/15417/)
Rustdoc
-----
- [Doctests can be ignored based on target names using `ignore-*` attributes.](https://github.com/rust-lang/rust/pull/137096)
- [Stabilize the `--test-runtool` and `--test-runtool-arg` CLI options to specify a program (like qemu) and its arguments to run a doctest.](https://github.com/rust-lang/rust/pull/137096)
Compatibility Notes
-------------------
- [Finish changing the internal representation of pasted tokens](https://github.com/rust-lang/rust/pull/124141). Certain invalid declarative macros that were previously accepted in obscure circumstances are now correctly rejected by the compiler. Use of a `tt` fragment specifier can often fix these macros.
- [Fully de-stabilize the `#[bench]` attribute](https://github.com/rust-lang/rust/pull/134273). Usage of `#[bench]` without `#![feature(custom_test_frameworks)]` already triggered a deny-by-default future-incompatibility lint since Rust 1.77, but will now become a hard error.
- [Fix borrow checking some always-true patterns.](https://github.com/rust-lang/rust/pull/139042)
The borrow checker was overly permissive in some cases, allowing programs that shouldn't have compiled.
- [Update the minimum external LLVM to 19.](https://github.com/rust-lang/rust/pull/139275)
- [Make it a hard error to use a vector type with a non-Rust ABI without enabling the required target feature.](https://github.com/rust-lang/rust/pull/139309)
Version 1.87.0 (2025-05-15)
==========================
Language
--------
- [Stabilize `asm_goto` feature](https://github.com/rust-lang/rust/pull/133870)
- [Allow parsing open beginning ranges (`..EXPR`) after unary operators `!`, `-`, and `*`](https://github.com/rust-lang/rust/pull/134900).
- [Don't require method impls for methods with `Self: Sized` bounds in `impl`s for unsized types](https://github.com/rust-lang/rust/pull/135480)
- [Stabilize `feature(precise_capturing_in_traits)` allowing `use<...>` bounds on return position `impl Trait` in `trait`s](https://github.com/rust-lang/rust/pull/138128)
Compiler
--------
- [x86: make SSE2 required for i686 targets and use it to pass SIMD types](https://github.com/rust-lang/rust/pull/135408)
Platform Support
----------------
- [Remove `i586-pc-windows-msvc` target](https://github.com/rust-lang/rust/pull/137957)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html
Libraries
---------
- [Stabilize the anonymous pipe API](https://github.com/rust-lang/rust/issues/127154)
- [Add support for unbounded left/right shift operations](https://github.com/rust-lang/rust/issues/129375)
- [Print pointer metadata in `Debug` impl of raw pointers](https://github.com/rust-lang/rust/pull/135080)
- [`Vec::with_capacity` guarantees it allocates with the amount requested, even if `Vec::capacity` returns a different number.](https://github.com/rust-lang/rust/pull/135933)
- Most `std::arch` intrinsics which don't take pointer arguments can now be called from safe code if the caller has the appropriate target features already enabled (https://github.com/rust-lang/stdarch/pull/1714, https://github.com/rust-lang/stdarch/pull/1716, https://github.com/rust-lang/stdarch/pull/1717)
- [Undeprecate `env::home_dir`](https://github.com/rust-lang/rust/pull/137327)
- [Denote `ControlFlow` as `#[must_use]`](https://github.com/rust-lang/rust/pull/137449)
- [Macros such as `assert_eq!` and `vec!` now support `const {...}` expressions](https://github.com/rust-lang/rust/pull/138162)
Stabilized APIs
---------------
- [`Vec::extract_if`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.extract_if)
- [`vec::ExtractIf`](https://doc.rust-lang.org/stable/std/vec/struct.ExtractIf.html)
- [`LinkedList::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.LinkedList.html#method.extract_if)
- [`linked_list::ExtractIf`](https://doc.rust-lang.org/stable/std/collections/linked_list/struct.ExtractIf.html)
- [`<[T]>::split_off`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off)
- [`<[T]>::split_off_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_mut)
- [`<[T]>::split_off_first`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_first)
- [`<[T]>::split_off_first_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_first_mut)
- [`<[T]>::split_off_last`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_last)
- [`<[T]>::split_off_last_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_off_last_mut)
- [`String::extend_from_within`](https://doc.rust-lang.org/stable/alloc/string/struct.String.html#method.extend_from_within)
- [`os_str::Display`](https://doc.rust-lang.org/stable/std/ffi/os_str/struct.Display.html)
- [`OsString::display`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.display)
- [`OsStr::display`](https://doc.rust-lang.org/stable/std/ffi/struct.OsStr.html#method.display)
- [`io::pipe`](https://doc.rust-lang.org/stable/std/io/fn.pipe.html)
- [`io::PipeReader`](https://doc.rust-lang.org/stable/std/io/struct.PipeReader.html)
- [`io::PipeWriter`](https://doc.rust-lang.org/stable/std/io/struct.PipeWriter.html)
- [`impl From for OwnedHandle`](https://doc.rust-lang.org/stable/std/os/windows/io/struct.OwnedHandle.html#impl-From%3CPipeReader%3E-for-OwnedHandle)
- [`impl From for OwnedHandle`](https://doc.rust-lang.org/stable/std/os/windows/io/struct.OwnedHandle.html#impl-From%3CPipeWriter%3E-for-OwnedHandle)
- [`impl From for Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html)
- [`impl From for Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CPipeWriter%3E-for-Stdio)
- [`impl From for OwnedFd`](https://doc.rust-lang.org/stable/std/os/fd/struct.OwnedFd.html#impl-From%3CPipeReader%3E-for-OwnedFd)
- [`impl From for OwnedFd`](https://doc.rust-lang.org/stable/std/os/fd/struct.OwnedFd.html#impl-From%3CPipeWriter%3E-for-OwnedFd)
- [`Box>::write`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.write)
- [`impl TryFrom> for String`](https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-TryFrom%3CVec%3Cu8%3E%3E-for-String)
- [`<*const T>::offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from_unsigned)
- [`<*const T>::byte_offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.byte_offset_from_unsigned)
- [`<*mut T>::offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from_unsigned-1)
- [`<*mut T>::byte_offset_from_unsigned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.byte_offset_from_unsigned-1)
- [`NonNull::offset_from_unsigned`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.offset_from_unsigned)
- [`NonNull::byte_offset_from_unsigned`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.byte_offset_from_unsigned)
- [`::cast_signed`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.cast_signed)
- [`NonZero::::cast_signed`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.cast_signed-5).
- [`::cast_unsigned`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.cast_unsigned).
- [`NonZero::::cast_unsigned`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.cast_unsigned-5).
- [`::is_multiple_of`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.is_multiple_of)
- [`::unbounded_shl`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unbounded_shl)
- [`::unbounded_shr`](https://doc.rust-lang.org/stable/std/primitive.usize.html#method.unbounded_shr)
- [`::unbounded_shl`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unbounded_shl)
- [`::unbounded_shr`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.unbounded_shr)
- [`::midpoint`](https://doc.rust-lang.org/stable/std/primitive.isize.html#method.midpoint)
- [`::from_utf8`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8)
- [`::from_utf8_mut`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8_mut)
- [`::from_utf8_unchecked`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8_unchecked)
- [`::from_utf8_unchecked_mut`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.from_utf8_unchecked_mut)
These previously stable APIs are now stable in const contexts:
- [`core::str::from_utf8_mut`](https://doc.rust-lang.org/stable/std/str/fn.from_utf8_mut.html)
- [`<[T]>::copy_from_slice`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.copy_from_slice)
- [`SocketAddr::set_ip`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.set_ip)
- [`SocketAddr::set_port`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.set_port),
- [`SocketAddrV4::set_ip`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.set_ip)
- [`SocketAddrV4::set_port`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.set_port),
- [`SocketAddrV6::set_ip`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_ip)
- [`SocketAddrV6::set_port`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_port)
- [`SocketAddrV6::set_flowinfo`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_flowinfo)
- [`SocketAddrV6::set_scope_id`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.set_scope_id)
- [`char::is_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_digit)
- [`char::is_whitespace`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_whitespace)
- [`<[[T; N]]>::as_flattened`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_flattened)
- [`<[[T; N]]>::as_flattened_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_flattened_mut)
- [`String::into_bytes`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.into_bytes)
- [`String::as_str`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_str)
- [`String::capacity`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.capacity)
- [`String::as_bytes`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_bytes)
- [`String::len`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.len)
- [`String::is_empty`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.is_empty)
- [`String::as_mut_str`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_mut_str)
- [`String::as_mut_vec`](https://doc.rust-lang.org/stable/std/string/struct.String.html#method.as_mut_vec)
- [`Vec::as_ptr`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_ptr)
- [`Vec::as_slice`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_slice)
- [`Vec::capacity`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.capacity)
- [`Vec::len`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.len)
- [`Vec::is_empty`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.is_empty)
- [`Vec::as_mut_slice`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_mut_slice)
- [`Vec::as_mut_ptr`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.as_mut_ptr)
Cargo
-----
- [Add terminal integration via ANSI OSC 9;4 sequences](https://github.com/rust-lang/cargo/pull/14615/)
- [chore: bump openssl to v3](https://github.com/rust-lang/cargo/pull/15232/)
- [feat(package): add --exclude-lockfile flag](https://github.com/rust-lang/cargo/pull/15234/)
Compatibility Notes
-------------------
- [Rust now raises an error for macro invocations inside the `#![crate_name]` attribute](https://github.com/rust-lang/rust/pull/127581)
- [Unstable fields are now always considered to be inhabited](https://github.com/rust-lang/rust/pull/133889)
- [Macro arguments of unary operators followed by open beginning ranges may now be matched differently](https://github.com/rust-lang/rust/pull/134900)
- [Make `Debug` impl of raw pointers print metadata if present](https://github.com/rust-lang/rust/pull/135080)
- [Warn against function pointers using unsupported ABI strings in dependencies](https://github.com/rust-lang/rust/pull/135767)
- [Associated types on `dyn` types are no longer deduplicated](https://github.com/rust-lang/rust/pull/136458)
- [Forbid attributes on `..` inside of struct patterns (`let Struct { #[attribute] .. }) =`](https://github.com/rust-lang/rust/pull/136490)
- [Make `ptr_cast_add_auto_to_object` lint into hard error](https://github.com/rust-lang/rust/pull/136764)
- Many `std::arch` intrinsics are now safe to call in some contexts, there may now be new `unused_unsafe` warnings in existing codebases.
- [Limit `width` and `precision` formatting options to 16 bits on all targets](https://github.com/rust-lang/rust/pull/136932)
- [Turn order dependent trait objects future incompat warning into a hard error](https://github.com/rust-lang/rust/pull/136968)
- [Denote `ControlFlow` as `#[must_use]`](https://github.com/rust-lang/rust/pull/137449)
- [Windows: The standard library no longer links `advapi32`, except on win7.](https://github.com/rust-lang/rust/pull/138233) Code such as C libraries that were relying on this assumption may need to explicitly link advapi32.
- [Proc macros can no longer observe expanded `cfg(true)` attributes.](https://github.com/rust-lang/rust/pull/138844)
- [Start changing the internal representation of pasted tokens](https://github.com/rust-lang/rust/pull/124141). Certain invalid declarative macros that were previously accepted in obscure circumstances are now correctly rejected by the compiler. Use of a `tt` fragment specifier can often fix these macros.
- [Don't allow flattened format_args in const.](https://github.com/rust-lang/rust/pull/139624)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Update to LLVM 20](https://github.com/rust-lang/rust/pull/135763)
Version 1.86.0 (2025-04-03)
==========================
Language
--------
- [Stabilize upcasting trait objects to supertraits.](https://github.com/rust-lang/rust/pull/134367)
- [Allow safe functions to be marked with the `#[target_feature]` attribute.](https://github.com/rust-lang/rust/pull/134090)
- [The `missing_abi` lint now warns-by-default.](https://github.com/rust-lang/rust/pull/132397)
- Rust now lints about double negations, to catch cases that might have intended to be a prefix decrement operator (`--x`) as written in other languages. This was previously a clippy lint, `clippy::double_neg`, and is [now available directly in Rust as `double_negations`.](https://github.com/rust-lang/rust/pull/126604)
- [More pointers are now detected as definitely not-null based on their alignment in const eval.](https://github.com/rust-lang/rust/pull/133700)
- [Empty `repr()` attribute applied to invalid items are now correctly rejected.](https://github.com/rust-lang/rust/pull/133925)
- [Inner attributes `#![test]` and `#![rustfmt::skip]` are no longer accepted in more places than intended.](https://github.com/rust-lang/rust/pull/134276)
Compiler
--------
- [Debug-assert that raw pointers are non-null on access.](https://github.com/rust-lang/rust/pull/134424)
- [Change `-O` to mean `-C opt-level=3` instead of `-C opt-level=2` to match Cargo's defaults.](https://github.com/rust-lang/rust/pull/135439)
- [Fix emission of `overflowing_literals` under certain macro environments.](https://github.com/rust-lang/rust/pull/136393)
Platform Support
----------------
- [Replace `i686-unknown-redox` target with `i586-unknown-redox`.](https://github.com/rust-lang/rust/pull/136698)
- [Increase baseline CPU of `i686-unknown-hurd-gnu` to Pentium 4.](https://github.com/rust-lang/rust/pull/136700)
- New tier 3 targets:
- [`{aarch64-unknown,x86_64-pc}-nto-qnx710_iosock`](https://github.com/rust-lang/rust/pull/133631).
For supporting Neutrino QNX 7.1 with `io-socket` network stack.
- [`{aarch64-unknown,x86_64-pc}-nto-qnx800`](https://github.com/rust-lang/rust/pull/133631).
For supporting Neutrino QNX 8.0 (`no_std`-only).
- [`{x86_64,i686}-win7-windows-gnu`](https://github.com/rust-lang/rust/pull/134609).
Intended for backwards compatibility with Windows 7. `{x86_64,i686}-win7-windows-msvc` are the Windows MSVC counterparts that already exist as Tier 3 targets.
- [`amdgcn-amd-amdhsa`](https://github.com/rust-lang/rust/pull/134740).
- [`x86_64-pc-cygwin`](https://github.com/rust-lang/rust/pull/134999).
- [`{mips,mipsel}-mti-none-elf`](https://github.com/rust-lang/rust/pull/135074).
Initial bare-metal support.
- [`m68k-unknown-none-elf`](https://github.com/rust-lang/rust/pull/135085).
- [`armv7a-nuttx-{eabi,eabihf}`, `aarch64-unknown-nuttx`, and `thumbv7a-nuttx-{eabi,eabihf}`](https://github.com/rust-lang/rust/pull/135757).
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- The type of `FromBytesWithNulError` in `CStr::from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, FromBytesWithNulError>` was [changed from an opaque struct to an enum](https://github.com/rust-lang/rust/pull/134143), allowing users to examine why the conversion failed.
- [Remove `RustcDecodable` and `RustcEncodable`.](https://github.com/rust-lang/rust/pull/134272)
- [Deprecate libtest's `--logfile` option.](https://github.com/rust-lang/rust/pull/134283)
- [On recent versions of Windows, `std::fs::remove_file` will now remove read-only files.](https://github.com/rust-lang/rust/pull/134679)
Stabilized APIs
---------------
- [`{float}::next_down`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.next_down)
- [`{float}::next_up`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.next_up)
- [`<[_]>::get_disjoint_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.get_disjoint_mut)
- [`<[_]>::get_disjoint_unchecked_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.get_disjoint_unchecked_mut)
- [`slice::GetDisjointMutError`](https://doc.rust-lang.org/stable/std/slice/enum.GetDisjointMutError.html)
- [`HashMap::get_disjoint_mut`](https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.get_disjoint_mut)
- [`HashMap::get_disjoint_unchecked_mut`](https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.get_disjoint_unchecked_mut)
- [`NonZero::count_ones`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.count_ones)
- [`Vec::pop_if`](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.pop_if)
- [`sync::Once::wait`](https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.wait)
- [`sync::Once::wait_force`](https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.wait_force)
- [`sync::OnceLock::wait`](https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html#method.wait)
These APIs are now stable in const contexts:
- [`hint::black_box`](https://doc.rust-lang.org/stable/std/hint/fn.black_box.html)
- [`io::Cursor::get_mut`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.get_mut)
- [`io::Cursor::set_position`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.set_position)
- [`str::is_char_boundary`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.is_char_boundary)
- [`str::split_at`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at)
- [`str::split_at_checked`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_checked)
- [`str::split_at_mut`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_mut)
- [`str::split_at_mut_checked`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_mut_checked)
Cargo
-----
- [When merging, replace rather than combine configuration keys that refer to a program path and its arguments.](https://github.com/rust-lang/cargo/pull/15066/)
- [Error if both `--package` and `--workspace` are passed but the requested package is missing.](https://github.com/rust-lang/cargo/pull/15071/) This was previously silently ignored, which was considered a bug since missing packages should be reported.
- [Deprecate the token argument in `cargo login` to avoid shell history leaks.](https://github.com/rust-lang/cargo/pull/15057/)
- [Simplify the implementation of `SourceID` comparisons.](https://github.com/rust-lang/cargo/pull/14980/) This may potentially change behavior if the canonicalized URL compares differently in alternative registries.
Rustdoc
-----
- [Add a sans-serif font setting.](https://github.com/rust-lang/rust/pull/133636)
Compatibility Notes
-------------------
- [The `wasm_c_abi` future compatibility warning is now a hard error.](https://github.com/rust-lang/rust/pull/133951)
Users of `wasm-bindgen` should upgrade to at least version 0.2.89, otherwise compilation will fail.
- [Remove long-deprecated no-op attributes `#![no_start]` and `#![crate_id]`.](https://github.com/rust-lang/rust/pull/134300)
- [The future incompatibility lint `cenum_impl_drop_cast` has been made into a hard error.](https://github.com/rust-lang/rust/pull/135964) This means it is now an error to cast a field-less enum to an integer if the enum implements `Drop`.
- [SSE2 is now required for "i686" 32-bit x86 hard-float targets; disabling it causes a warning that will become a hard error eventually.](https://github.com/rust-lang/rust/pull/137037)
To compile for pre-SSE2 32-bit x86, use a "i586" target instead.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Build the rustc on AArch64 Linux with ThinLTO + PGO.](https://github.com/rust-lang/rust/pull/133807)
The ARM 64-bit compiler (AArch64) on Linux is now optimized with ThinLTO and PGO, similar to the optimizations we have already performed for the x86-64 compiler on Linux. This should make it up to 30% faster.
Version 1.85.1 (2025-03-18)
==========================
- [Fix the doctest-merging feature of the 2024 Edition.](https://github.com/rust-lang/rust/pull/137899/)
- [Relax some `target_feature` checks when generating docs.](https://github.com/rust-lang/rust/pull/137632/)
- [Fix errors in `std::fs::rename` on Windows 10, version 1607.](https://github.com/rust-lang/rust/pull/137528/)
- [Downgrade bootstrap `cc` to fix custom targets.](https://github.com/rust-lang/rust/pull/137460/)
- [Skip submodule updates when building Rust from a source tarball.](https://github.com/rust-lang/rust/pull/137338/)
Version 1.85.0 (2025-02-20)
==========================
Language
--------
- [The 2024 Edition is now stable.](https://github.com/rust-lang/rust/pull/133349)
See [the edition guide](https://doc.rust-lang.org/nightly/edition-guide/rust-2024/index.html) for more details.
- [Stabilize async closures](https://github.com/rust-lang/rust/pull/132706)
See [RFC 3668](https://rust-lang.github.io/rfcs/3668-async-closures.html) for more details.
- [Stabilize `#[diagnostic::do_not_recommend]`](https://github.com/rust-lang/rust/pull/132056)
- [Add `unpredictable_function_pointer_comparisons` lint to warn against function pointer comparisons](https://github.com/rust-lang/rust/pull/118833)
- [Lint on combining `#[no_mangle]` and `#[export_name]` attributes.](https://github.com/rust-lang/rust/pull/131558)
Compiler
--------
- [The unstable flag `-Zpolymorphize` has been removed](https://github.com/rust-lang/rust/pull/133883), see https://github.com/rust-lang/compiler-team/issues/810 for some background.
Platform Support
----------------
- [Promote `powerpc64le-unknown-linux-musl` to tier 2 with host tools](https://github.com/rust-lang/rust/pull/133801)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Panics in the standard library now have a leading `library/` in their path](https://github.com/rust-lang/rust/pull/132390)
- [`std::env::home_dir()` on Windows now ignores the non-standard `$HOME` environment variable](https://github.com/rust-lang/rust/pull/132515)
It will be un-deprecated in a subsequent release.
- [Add `AsyncFn*` to the prelude in all editions.](https://github.com/rust-lang/rust/pull/132611)
Stabilized APIs
---------------
- [`BuildHasherDefault::new`](https://doc.rust-lang.org/stable/std/hash/struct.BuildHasherDefault.html#method.new)
- [`ptr::fn_addr_eq`](https://doc.rust-lang.org/std/ptr/fn.fn_addr_eq.html)
- [`io::ErrorKind::QuotaExceeded`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.QuotaExceeded)
- [`io::ErrorKind::CrossesDevices`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.CrossesDevices)
- [`{float}::midpoint`](https://doc.rust-lang.org/core/primitive.f32.html#method.midpoint)
- [Unsigned `{integer}::midpoint`](https://doc.rust-lang.org/std/primitive.u64.html#method.midpoint)
- [`NonZeroU*::midpoint`](https://doc.rust-lang.org/std/num/type.NonZeroU32.html#method.midpoint)
- [impl `std::iter::Extend` for tuples with arity 1 through 12](https://doc.rust-lang.org/stable/std/iter/trait.Extend.html#impl-Extend%3C(A,)%3E-for-(EA,))
- [`FromIterator<(A, ...)>` for tuples with arity 1 through 12](https://doc.rust-lang.org/stable/std/iter/trait.FromIterator.html#impl-FromIterator%3C(EA,)%3E-for-(A,))
- [`std::task::Waker::noop`](https://doc.rust-lang.org/stable/std/task/struct.Waker.html#method.noop)
These APIs are now stable in const contexts:
- [`mem::size_of_val`](https://doc.rust-lang.org/stable/std/mem/fn.size_of_val.html)
- [`mem::align_of_val`](https://doc.rust-lang.org/stable/std/mem/fn.align_of_val.html)
- [`Layout::for_value`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.for_value)
- [`Layout::align_to`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.align_to)
- [`Layout::pad_to_align`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.pad_to_align)
- [`Layout::extend`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.extend)
- [`Layout::array`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.array)
- [`std::mem::swap`](https://doc.rust-lang.org/stable/std/mem/fn.swap.html)
- [`std::ptr::swap`](https://doc.rust-lang.org/stable/std/ptr/fn.swap.html)
- [`NonNull::new`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.new)
- [`HashMap::with_hasher`](https://doc.rust-lang.org/stable/std/collections/struct.HashMap.html#method.with_hasher)
- [`HashSet::with_hasher`](https://doc.rust-lang.org/stable/std/collections/struct.HashSet.html#method.with_hasher)
- [`BuildHasherDefault::new`](https://doc.rust-lang.org/stable/std/hash/struct.BuildHasherDefault.html#method.new)
- [`::recip`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.recip)
- [`::to_degrees`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.to_degrees)
- [`::to_radians`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.to_radians)
- [`::max`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.max)
- [`::min`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.min)
- [`::clamp`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.clamp)
- [`::abs`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.abs)
- [`::signum`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.signum)
- [`::copysign`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.copysign)
- [`MaybeUninit::write`](https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.write)
Cargo
-----
- [Add future-incompatibility warning against keywords in cfgs and add raw-idents](https://github.com/rust-lang/cargo/pull/14671/)
- [Stabilize higher precedence trailing flags](https://github.com/rust-lang/cargo/pull/14900/)
- [Pass `CARGO_CFG_FEATURE` to build scripts](https://github.com/rust-lang/cargo/pull/14902/)
Rustdoc
-----
- [Doc comment on impl blocks shows the first line, even when the impl block is collapsed](https://github.com/rust-lang/rust/pull/132155)
Compatibility Notes
-------------------
- [`rustc` no longer treats the `test` cfg as a well known check-cfg](https://github.com/rust-lang/rust/pull/131729), instead it is up to the build systems and users of `--check-cfg`[^check-cfg] to set it as a well known cfg using `--check-cfg=cfg(test)`.
This is done to enable build systems like Cargo to set it conditionally, as not all source files are suitable for unit tests.
[Cargo (for now) unconditionally sets the `test` cfg as a well known cfg](https://github.com/rust-lang/cargo/pull/14963).
[^check-cfg]: https://doc.rust-lang.org/nightly/rustc/check-cfg.html
- [Disable potentially incorrect type inference if there are trivial and non-trivial where-clauses](https://github.com/rust-lang/rust/pull/132325)
- `std::env::home_dir()` has been deprecated for years, because it can give surprising results in some Windows configurations if the `HOME` environment variable is set (which is not the normal configuration on Windows). We had previously avoided changing its behavior, out of concern for compatibility with code depending on this non-standard configuration. Given how long this function has been deprecated, we're now fixing its behavior as a bugfix. A subsequent release will remove the deprecation for this function.
- [Make `core::ffi::c_char` signedness more closely match that of the platform-default `char`](https://github.com/rust-lang/rust/pull/132975)
This changed `c_char` from an `i8` to `u8` or vice versa on many Tier 2 and 3
targets (mostly Arm and RISC-V embedded targets). The new definition may
result in compilation failures but fixes compatibility issues with C.
The `libc` crate matches this change as of its 0.2.169 release.
- [When compiling a nested `macro_rules` macro from an external crate, the content of the inner `macro_rules` is now built with the edition of the external crate, not the local crate.](https://github.com/rust-lang/rust/pull/133274)
- [Increase `sparcv9-sun-solaris` and `x86_64-pc-solaris` Solaris baseline to 11.4.](https://github.com/rust-lang/rust/pull/133293)
- [Show `abi_unsupported_vector_types` lint in future breakage reports](https://github.com/rust-lang/rust/pull/133374)
- [Error if multiple super-trait instantiations of `dyn Trait` need associated types to be specified but only one is provided](https://github.com/rust-lang/rust/pull/133392)
- [Change `powerpc64-ibm-aix` default `codemodel` to large](https://github.com/rust-lang/rust/pull/133811)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Build `x86_64-unknown-linux-gnu` with LTO for C/C++ code (e.g., `jemalloc`)](https://github.com/rust-lang/rust/pull/134690)
Version 1.84.1 (2025-01-30)
==========================
- [Fix ICE 132920 in duplicate-crate diagnostics.](https://github.com/rust-lang/rust/pull/133304/)
- [Fix errors for overlapping impls in incremental rebuilds.](https://github.com/rust-lang/rust/pull/133828/)
- [Fix slow compilation related to the next-generation trait solver.](https://github.com/rust-lang/rust/pull/135618/)
- [Fix debuginfo when LLVM's location discriminator value limit is exceeded.](https://github.com/rust-lang/rust/pull/135643/)
- Fixes for building Rust from source:
- [Only try to distribute `llvm-objcopy` if llvm tools are enabled.](https://github.com/rust-lang/rust/pull/134240/)
- [Add Profile Override for Non-Git Sources.](https://github.com/rust-lang/rust/pull/135433/)
- [Resolve symlinks of LLVM tool binaries before copying them.](https://github.com/rust-lang/rust/pull/135585/)
- [Make it possible to use ci-rustc on tarball sources.](https://github.com/rust-lang/rust/pull/135722/)
Version 1.84.0 (2025-01-09)
==========================
Language
--------
- [Allow `#[deny]` inside `#[forbid]` as a no-op](https://github.com/rust-lang/rust/pull/121560/)
- [Show a warning when `-Ctarget-feature` is used to toggle features that can lead to unsoundness due to ABI mismatches](https://github.com/rust-lang/rust/pull/129884)
- [Use the next-generation trait solver in coherence](https://github.com/rust-lang/rust/pull/130654)
- [Allow coercions to drop the principal of trait objects](https://github.com/rust-lang/rust/pull/131857)
- [Support `/` as the path separator for `include!()` in all cases on Windows](https://github.com/rust-lang/rust/pull/125205)
- [Taking a raw ref (`raw (const|mut)`) of a deref of a pointer (`*ptr`) is now safe](https://github.com/rust-lang/rust/pull/129248)
- [Stabilize s390x inline assembly](https://github.com/rust-lang/rust/pull/131258)
- [Stabilize Arm64EC inline assembly](https://github.com/rust-lang/rust/pull/131781)
- [Lint against creating pointers to immediately dropped temporaries](https://github.com/rust-lang/rust/pull/128985)
- [Execute drop glue when unwinding in an `extern "C"` function](https://github.com/rust-lang/rust/pull/129582)
Compiler
--------
- [Add `--print host-tuple` flag to print the host target tuple and affirm the "target tuple" terminology over "target triple"](https://github.com/rust-lang/rust/pull/125579)
- [Declaring functions with a calling convention not supported on the current target now triggers a hard error](https://github.com/rust-lang/rust/pull/129935)
- [Set up indirect access to external data for `loongarch64-unknown-linux-{musl,ohos}`](https://github.com/rust-lang/rust/pull/131583)
- [Enable XRay instrumentation for LoongArch Linux targets](https://github.com/rust-lang/rust/pull/131818)
- [Extend the `unexpected_cfgs` lint to also warn in external macros](https://github.com/rust-lang/rust/pull/132577)
- [Stabilize WebAssembly `multivalue`, `reference-types`, and `tail-call` target features](https://github.com/rust-lang/rust/pull/131080)
- [Added Tier 2 support for the `wasm32v1-none` target](https://github.com/rust-lang/rust/pull/131487)
Libraries
---------
- [Implement `From<&mut {slice}>` for `Box/Rc/Arc<{slice}>`](https://github.com/rust-lang/rust/pull/129329)
- [Move `::copysign`, `::abs`, `::signum` to `core`](https://github.com/rust-lang/rust/pull/131304)
- [Add `LowerExp` and `UpperExp` implementations to `NonZero`](https://github.com/rust-lang/rust/pull/131377)
- [Implement `FromStr` for `CString` and `TryFrom` for `String`](https://github.com/rust-lang/rust/pull/130608)
- [`std::os::darwin` has been made public](https://github.com/rust-lang/rust/pull/123723)
Stabilized APIs
---------------
- [`Ipv6Addr::is_unique_local`](https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.is_unique_local)
- [`Ipv6Addr::is_unicast_link_local`](https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.is_unicast_link_local)
- [`core::ptr::with_exposed_provenance`](https://doc.rust-lang.org/stable/core/ptr/fn.with_exposed_provenance.html)
- [`core::ptr::with_exposed_provenance_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.with_exposed_provenance_mut.html)
- [`::addr`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.addr)
- [`::expose_provenance`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.expose_provenance)
- [`::with_addr`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.with_addr)
- [`::map_addr`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.map_addr)
- [`::isqrt`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.isqrt)
- [`::checked_isqrt`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.checked_isqrt)
- [`::isqrt`](https://doc.rust-lang.org/stable/core/primitive.u32.html#method.isqrt)
- [`NonZero::isqrt`](https://doc.rust-lang.org/stable/core/num/struct.NonZero.html#impl-NonZero%3Cu128%3E/method.isqrt)
- [`core::ptr::without_provenance`](https://doc.rust-lang.org/stable/core/ptr/fn.without_provenance.html)
- [`core::ptr::without_provenance_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.without_provenance_mut.html)
- [`core::ptr::dangling`](https://doc.rust-lang.org/stable/core/ptr/fn.dangling.html)
- [`core::ptr::dangling_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.dangling_mut.html)
- [`Pin::as_deref_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.as_deref_mut)
These APIs are now stable in const contexts
- [`AtomicBool::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.from_ptr)
- [`AtomicPtr::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicPtr.html#method.from_ptr)
- [`AtomicU8::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU8.html#method.from_ptr)
- [`AtomicU16::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU16.html#method.from_ptr)
- [`AtomicU32::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU32.html#method.from_ptr)
- [`AtomicU64::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicU64.html#method.from_ptr)
- [`AtomicUsize::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.from_ptr)
- [`AtomicI8::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI8.html#method.from_ptr)
- [`AtomicI16::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI16.html#method.from_ptr)
- [`AtomicI32::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI32.html#method.from_ptr)
- [`AtomicI64::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicI64.html#method.from_ptr)
- [`AtomicIsize::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicIsize.html#method.from_ptr)
- [`::is_null`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_null-1)
- [`::as_ref`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.as_ref-1)
- [`::as_mut`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.as_mut)
- [`Pin::new`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.new)
- [`Pin::new_unchecked`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.new_unchecked)
- [`Pin::get_ref`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_ref)
- [`Pin::into_ref`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.into_ref)
- [`Pin::get_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_mut)
- [`Pin::get_unchecked_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.get_unchecked_mut)
- [`Pin::static_ref`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.static_ref)
- [`Pin::static_mut`](https://doc.rust-lang.org/stable/core/pin/struct.Pin.html#method.static_mut)
Cargo
-----
- [Stabilize MSRV-aware resolver config](https://github.com/rust-lang/cargo/pull/14639/)
- [Stabilize resolver v3](https://github.com/rust-lang/cargo/pull/14754/)
Rustdoc
-------
- [rustdoc-search: improve type-driven search](https://github.com/rust-lang/rust/pull/127589)
Compatibility Notes
-------------------
- [Enable by default the `LSX` target feature for LoongArch Linux targets](https://github.com/rust-lang/rust/pull/132140)
- [The unstable `-Zprofile` flag (“gcov-style” coverage instrumentation) has been removed.](https://github.com/rust-lang/rust/pull/131829) This does not affect the stable flags for coverage instrumentation (`-Cinstrument-coverage`) and profile-guided optimization (`-Cprofile-generate`, `-Cprofile-use`), which are unrelated and remain available.
- Support for the target named `wasm32-wasi` has been removed as the target is now named `wasm32-wasip1`. This completes the [transition](https://github.com/rust-lang/compiler-team/issues/607) [plan](https://github.com/rust-lang/compiler-team/issues/695) for this target following [the introduction of `wasm32-wasip1`](https://github.com/rust-lang/rust/pull/120468) in Rust 1.78. Compiler warnings on [use of `wasm32-wasi`](https://github.com/rust-lang/rust/pull/126662) introduced in Rust 1.81 are now gone as well as the target is removed.
- [The syntax `&pin (mut|const) T` is now parsed as a type which in theory could affect macro expansion results in some edge cases](https://github.com/rust-lang/rust/pull/130635#issuecomment-2375462821)
- [Legacy syntax for calling `std::arch` functions is no longer permitted to declare items or bodies (such as closures, inline consts, or async blocks).](https://github.com/rust-lang/rust/pull/130443#issuecomment-2445678945)
- [Declaring functions with a calling convention not supported on the current target now triggers a hard error](https://github.com/rust-lang/rust/pull/129935)
- [The next-generation trait solver is now enabled for coherence, fixing multiple soundness issues](https://github.com/rust-lang/rust/pull/130654)
Version 1.83.0 (2024-11-28)
==========================
Language
--------
- [Stabilize `&mut`, `*mut`, `&Cell`, and `*const Cell` in const.](https://github.com/rust-lang/rust/pull/129195)
- [Allow creating references to statics in `const` initializers.](https://github.com/rust-lang/rust/pull/129759)
- [Implement raw lifetimes and labels (`'r#ident`).](https://github.com/rust-lang/rust/pull/126452)
- [Define behavior when atomic and non-atomic reads race.](https://github.com/rust-lang/rust/pull/128778)
- [Non-exhaustive structs may now be empty.](https://github.com/rust-lang/rust/pull/128934)
- [Disallow implicit coercions from places of type `!`](https://github.com/rust-lang/rust/pull/129392)
- [`const extern` functions can now be defined for other calling conventions.](https://github.com/rust-lang/rust/pull/129753)
- [Stabilize `expr_2021` macro fragment specifier in all editions.](https://github.com/rust-lang/rust/pull/129972)
- [The `non_local_definitions` lint now fires on less code and warns by default.](https://github.com/rust-lang/rust/pull/127117)
Compiler
--------
- [Deprecate unsound `-Csoft-float` flag.](https://github.com/rust-lang/rust/pull/129897)
- Add many new tier 3 targets:
- [`aarch64_unknown_nto_qnx700`](https://github.com/rust-lang/rust/pull/127897)
- [`arm64e-apple-tvos`](https://github.com/rust-lang/rust/pull/130614)
- [`armv7-rtems-eabihf`](https://github.com/rust-lang/rust/pull/127021)
- [`loongarch64-unknown-linux-ohos`](https://github.com/rust-lang/rust/pull/130750)
- [`riscv32-wrs-vxworks` and `riscv64-wrs-vxworks`](https://github.com/rust-lang/rust/pull/130549)
- [`riscv32{e|em|emc}-unknown-none-elf`](https://github.com/rust-lang/rust/pull/130555)
- [`x86_64-unknown-hurd-gnu`](https://github.com/rust-lang/rust/pull/128345)
- [`x86_64-unknown-trusty`](https://github.com/rust-lang/rust/pull/130453)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Implement `PartialEq` for `ExitCode`.](https://github.com/rust-lang/rust/pull/127633)
- [Document that `catch_unwind` can deal with foreign exceptions without UB, although the exact behavior is unspecified.](https://github.com/rust-lang/rust/pull/128321)
- [Implement `Default` for `HashMap`/`HashSet` iterators that don't already have it.](https://github.com/rust-lang/rust/pull/128711)
- [Bump Unicode to version 16.0.0.](https://github.com/rust-lang/rust/pull/130183)
- [Change documentation of `ptr::add`/`sub` to not claim equivalence with `offset`.](https://github.com/rust-lang/rust/pull/130229)
Stabilized APIs
---------------
- [`BufRead::skip_until`](https://doc.rust-lang.org/stable/std/io/trait.BufRead.html#method.skip_until)
- [`ControlFlow::break_value`](https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.break_value)
- [`ControlFlow::continue_value`](https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.continue_value)
- [`ControlFlow::map_break`](https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.map_break)
- [`ControlFlow::map_continue`](https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.map_continue)
- [`DebugList::finish_non_exhaustive`](https://doc.rust-lang.org/stable/core/fmt/struct.DebugList.html#method.finish_non_exhaustive)
- [`DebugMap::finish_non_exhaustive`](https://doc.rust-lang.org/stable/core/fmt/struct.DebugMap.html#method.finish_non_exhaustive)
- [`DebugSet::finish_non_exhaustive`](https://doc.rust-lang.org/stable/core/fmt/struct.DebugSet.html#method.finish_non_exhaustive)
- [`DebugTuple::finish_non_exhaustive`](https://doc.rust-lang.org/stable/core/fmt/struct.DebugTuple.html#method.finish_non_exhaustive)
- [`ErrorKind::ArgumentListTooLong`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.ArgumentListTooLong)
- [`ErrorKind::Deadlock`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.Deadlock)
- [`ErrorKind::DirectoryNotEmpty`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.DirectoryNotEmpty)
- [`ErrorKind::ExecutableFileBusy`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.ExecutableFileBusy)
- [`ErrorKind::FileTooLarge`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.FileTooLarge)
- [`ErrorKind::HostUnreachable`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.HostUnreachable)
- [`ErrorKind::IsADirectory`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.IsADirectory)
- [`ErrorKind::NetworkDown`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.NetworkDown)
- [`ErrorKind::NetworkUnreachable`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.NetworkUnreachable)
- [`ErrorKind::NotADirectory`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.NotADirectory)
- [`ErrorKind::NotSeekable`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.NotSeekable)
- [`ErrorKind::ReadOnlyFilesystem`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.ReadOnlyFilesystem)
- [`ErrorKind::ResourceBusy`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.ResourceBusy)
- [`ErrorKind::StaleNetworkFileHandle`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.StaleNetworkFileHandle)
- [`ErrorKind::StorageFull`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.StorageFull)
- [`ErrorKind::TooManyLinks`](https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.TooManyLinks)
- [`Option::get_or_insert_default`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.get_or_insert_default)
- [`Waker::data`](https://doc.rust-lang.org/stable/core/task/struct.Waker.html#method.data)
- [`Waker::new`](https://doc.rust-lang.org/stable/core/task/struct.Waker.html#method.new)
- [`Waker::vtable`](https://doc.rust-lang.org/stable/core/task/struct.Waker.html#method.vtable)
- [`char::MIN`](https://doc.rust-lang.org/stable/core/primitive.char.html#associatedconstant.MIN)
- [`hash_map::Entry::insert_entry`](https://doc.rust-lang.org/stable/std/collections/hash_map/enum.Entry.html#method.insert_entry)
- [`hash_map::VacantEntry::insert_entry`](https://doc.rust-lang.org/stable/std/collections/hash_map/struct.VacantEntry.html#method.insert_entry)
These APIs are now stable in const contexts:
- [`Cell::into_inner`](https://doc.rust-lang.org/stable/core/cell/struct.Cell.html#method.into_inner)
- [`Duration::as_secs_f32`](https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.as_secs_f32)
- [`Duration::as_secs_f64`](https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.as_secs_f64)
- [`Duration::div_duration_f32`](https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.div_duration_f32)
- [`Duration::div_duration_f64`](https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.div_duration_f64)
- [`MaybeUninit::as_mut_ptr`](https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.as_mut_ptr)
- [`NonNull::as_mut`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.as_mut)
- [`NonNull::copy_from`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.copy_from)
- [`NonNull::copy_from_nonoverlapping`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.copy_from_nonoverlapping)
- [`NonNull::copy_to`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.copy_to)
- [`NonNull::copy_to_nonoverlapping`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.copy_to_nonoverlapping)
- [`NonNull::slice_from_raw_parts`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.slice_from_raw_parts)
- [`NonNull::write`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.write)
- [`NonNull::write_bytes`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.write_bytes)
- [`NonNull::write_unaligned`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.write_unaligned)
- [`OnceCell::into_inner`](https://doc.rust-lang.org/stable/core/cell/struct.OnceCell.html#method.into_inner)
- [`Option::as_mut`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_mut)
- [`Option::expect`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.expect)
- [`Option::replace`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.replace)
- [`Option::take`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.take)
- [`Option::unwrap`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.unwrap)
- [`Option::unwrap_unchecked`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.unwrap_unchecked)
- [`Option::<&_>::copied`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.copied)
- [`Option::<&mut _>::copied`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.copied-1)
- [`Option::>::flatten`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.flatten)
- [`Option::>::transpose`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.transpose)
- [`RefCell::into_inner`](https://doc.rust-lang.org/stable/core/cell/struct.RefCell.html#method.into_inner)
- [`Result::as_mut`](https://doc.rust-lang.org/stable/core/result/enum.Result.html#method.as_mut)
- [`Result::<&_, _>::copied`](https://doc.rust-lang.org/stable/core/result/enum.Result.html#method.copied)
- [`Result::<&mut _, _>::copied`](https://doc.rust-lang.org/stable/core/result/enum.Result.html#method.copied-1)
- [`Result::, _>::transpose`](https://doc.rust-lang.org/stable/core/result/enum.Result.html#method.transpose)
- [`UnsafeCell::get_mut`](https://doc.rust-lang.org/stable/core/cell/struct.UnsafeCell.html#method.get_mut)
- [`UnsafeCell::into_inner`](https://doc.rust-lang.org/stable/core/cell/struct.UnsafeCell.html#method.into_inner)
- [`array::from_mut`](https://doc.rust-lang.org/stable/core/array/fn.from_mut.html)
- [`char::encode_utf8`](https://doc.rust-lang.org/stable/core/primitive.char.html#method.encode_utf8)
- [`{float}::classify`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.classify)
- [`{float}::is_finite`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_finite)
- [`{float}::is_infinite`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_infinite)
- [`{float}::is_nan`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_nan)
- [`{float}::is_normal`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_normal)
- [`{float}::is_sign_negative`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_sign_negative)
- [`{float}::is_sign_positive`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_sign_positive)
- [`{float}::is_subnormal`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.is_subnormal)
- [`{float}::from_bits`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.from_bits)
- [`{float}::from_be_bytes`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.from_be_bytes)
- [`{float}::from_le_bytes`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.from_le_bytes)
- [`{float}::from_ne_bytes`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.from_ne_bytes)
- [`{float}::to_bits`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.to_bits)
- [`{float}::to_be_bytes`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.to_be_bytes)
- [`{float}::to_le_bytes`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.to_le_bytes)
- [`{float}::to_ne_bytes`](https://doc.rust-lang.org/stable/core/primitive.f64.html#method.to_ne_bytes)
- [`mem::replace`](https://doc.rust-lang.org/stable/core/mem/fn.replace.html)
- [`ptr::replace`](https://doc.rust-lang.org/stable/core/ptr/fn.replace.html)
- [`ptr::slice_from_raw_parts_mut`](https://doc.rust-lang.org/stable/core/ptr/fn.slice_from_raw_parts_mut.html)
- [`ptr::write`](https://doc.rust-lang.org/stable/core/ptr/fn.write.html)
- [`ptr::write_unaligned`](https://doc.rust-lang.org/stable/core/ptr/fn.write_unaligned.html)
- [`<*const _>::copy_to`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.copy_to)
- [`<*const _>::copy_to_nonoverlapping`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.copy_to_nonoverlapping)
- [`<*mut _>::copy_from`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.copy_from)
- [`<*mut _>::copy_from_nonoverlapping`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.copy_from_nonoverlapping)
- [`<*mut _>::copy_to`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.copy_to-1)
- [`<*mut _>::copy_to_nonoverlapping`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.copy_to_nonoverlapping-1)
- [`<*mut _>::write`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.write)
- [`<*mut _>::write_bytes`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.write_bytes)
- [`<*mut _>::write_unaligned`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.write_unaligned)
- [`slice::from_mut`](https://doc.rust-lang.org/stable/core/slice/fn.from_mut.html)
- [`slice::from_raw_parts_mut`](https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts_mut.html)
- [`<[_]>::first_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.first_mut)
- [`<[_]>::last_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.last_mut)
- [`<[_]>::first_chunk_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.first_chunk_mut)
- [`<[_]>::last_chunk_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.last_chunk_mut)
- [`<[_]>::split_at_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_mut)
- [`<[_]>::split_at_mut_checked`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_mut_checked)
- [`<[_]>::split_at_mut_unchecked`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_mut_unchecked)
- [`<[_]>::split_first_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_first_mut)
- [`<[_]>::split_last_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_last_mut)
- [`<[_]>::split_first_chunk_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_first_chunk_mut)
- [`<[_]>::split_last_chunk_mut`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_last_chunk_mut)
- [`str::as_bytes_mut`](https://doc.rust-lang.org/stable/core/primitive.str.html#method.as_bytes_mut)
- [`str::as_mut_ptr`](https://doc.rust-lang.org/stable/core/primitive.str.html#method.as_mut_ptr)
- [`str::from_utf8_unchecked_mut`](https://doc.rust-lang.org/stable/core/str/fn.from_utf8_unchecked_mut.html)
Cargo
-----
- [Introduced a new `CARGO_MANIFEST_PATH` environment variable, similar to `CARGO_MANIFEST_DIR` but pointing directly to the manifest file.](https://github.com/rust-lang/cargo/pull/14404/)
- [Added `package.autolib` to the manifest, allowing `[lib]` auto-discovery to be disabled.](https://github.com/rust-lang/cargo/pull/14591/)
- [Declare support level for each crate in Cargo's Charter / crate docs.](https://github.com/rust-lang/cargo/pull/14600/)
- [Declare new Intentional Artifacts as 'small' changes.](https://github.com/rust-lang/cargo/pull/14599/)
Rustdoc
-------
- [The sidebar / hamburger menu table of contents now includes the `# headers` from the main item's doc comment](https://github.com/rust-lang/rust/pull/120736). This is similar to a third-party feature provided by the rustdoc-search-enhancements browser extension.
Compatibility Notes
-------------------
- [Warn against function pointers using unsupported ABI strings.](https://github.com/rust-lang/rust/pull/128784)
- [Check well-formedness of the source type's signature in fn pointer casts.](https://github.com/rust-lang/rust/pull/129021) This partly closes a soundness hole that comes when casting a function item to function pointer
- [Use equality instead of subtyping when resolving type dependent paths.](https://github.com/rust-lang/rust/pull/129073)
- Linking on macOS now correctly includes Rust's default deployment target. Due to a linker bug, you might have to pass `MACOSX_DEPLOYMENT_TARGET` or fix your `#[link]` attributes to point to the correct frameworks. See .
- [Rust will now correctly raise an error for `repr(Rust)` written on non-`struct`/`enum`/`union` items, since it previously did not have any effect.](https://github.com/rust-lang/rust/pull/129422)
- The future incompatibility lint `deprecated_cfg_attr_crate_type_name` [has been made into a hard error](https://github.com/rust-lang/rust/pull/129670). It was used to deny usage of `#![crate_type]` and `#![crate_name]` attributes in `#![cfg_attr]`, which required a hack in the compiler to be able to change the used crate type and crate name after cfg expansion.
Users can use `--crate-type` instead of `#![cfg_attr(..., crate_type = "...")]` and `--crate-name` instead of `#![cfg_attr(..., crate_name = "...")]` when running `rustc`/`cargo rustc` on the command line.
Use of those two attributes outside of `#![cfg_attr]` continue to be fully supported.
- Until now, paths into the sysroot were always prefixed with `/rustc/$hash` in diagnostics, codegen, backtrace, e.g.
```
thread 'main' panicked at 'hello world', map-panic.rs:2:50
stack backtrace:
0: std::panicking::begin_panic
at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library/std/src/panicking.rs:616:12
1: map_panic::main::{{closure}}
at ./map-panic.rs:2:50
2: core::option::Option::map
at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library/core/src/option.rs:929:29
3: map_panic::main
at ./map-panic.rs:2:30
4: core::ops::function::FnOnce::call_once
at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library/core/src/ops/function.rs:248:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
```
[RFC 3127 said](https://rust-lang.github.io/rfcs/3127-trim-paths.html#changing-handling-of-sysroot-path-in-rustc)
> We want to change this behaviour such that, when `rust-src` source files can be discovered, the virtual path is discarded and therefore the local path will be embedded, unless there is a `--remap-path-prefix` that causes this local path to be remapped in the usual way.
[#129687](https://github.com/rust-lang/rust/pull/129687) implements this behaviour, when `rust-src` is present at compile time, `rustc` replaces `/rustc/$hash` with a real path into the local `rust-src` component with best effort.
To sanitize this, users must explicitly supply `--remap-path-prefix==foo` or not have the `rust-src` component installed.
- The allow-by-default `missing_docs` lint used to disable itself when invoked through `rustc --test`/`cargo test`, resulting in `#[expect(missing_docs)]` emitting false positives due to the expectation being wrongly unfulfilled. This behavior [has now been removed](https://github.com/rust-lang/rust/pull/130025), which allows `#[expect(missing_docs)]` to be fulfilled in all scenarios, but will also report new `missing_docs` diagnostics for publicly reachable `#[cfg(test)]` items, [integration test](https://doc.rust-lang.org/cargo/reference/cargo-targets.html#integration-tests) crate-level documentation, and publicly reachable items in integration tests.
- [The `armv8r-none-eabihf` target now uses the Armv8-R required set of floating-point features.](https://github.com/rust-lang/rust/pull/130295)
- [Fix a soundness bug where rustc wouldn't detect unconstrained higher-ranked lifetimes in a `dyn Trait`'s associated types that occur due to supertraits.](https://github.com/rust-lang/rust/pull/130367)
- [Update the minimum external LLVM version to 18.](https://github.com/rust-lang/rust/pull/130487)
- [Remove `aarch64-fuchsia` and `x86_64-fuchsia` target aliases in favor of `aarch64-unknown-fuchsia` and `x86_64-unknown-fuchsia` respectively.](https://github.com/rust-lang/rust/pull/130657)
- [The ABI-level exception class of a Rust panic is now encoded with native-endian bytes, so it is legible in hex dumps.](https://github.com/rust-lang/rust/pull/130897)
- [Visual Studio 2013 is no longer supported for MSVC targets.](https://github.com/rust-lang/rust/pull/131070)
- [The sysroot no longer contains the `std` dynamic library in its top-level `lib/` dir.](https://github.com/rust-lang/rust/pull/131188)
Version 1.82.0 (2024-10-17)
==========================
Language
--------
- [Don't make statement nonterminals match pattern nonterminals](https://github.com/rust-lang/rust/pull/120221/)
- [Patterns matching empty types can now be omitted in common cases](https://github.com/rust-lang/rust/pull/122792)
- [Enforce supertrait outlives obligations when using trait impls](https://github.com/rust-lang/rust/pull/124336)
- [`addr_of(_mut)!` macros and the newly stabilized `&raw (const|mut)` are now safe to use with all static items](https://github.com/rust-lang/rust/pull/125834)
- [size_of_val_raw: for length 0 this is safe to call](https://github.com/rust-lang/rust/pull/126152/)
- [Reorder trait bound modifiers *after* `for<...>` binder in trait bounds](https://github.com/rust-lang/rust/pull/127054/)
- [Stabilize `+ use<'lt>` opaque type precise capturing (RFC 3617)](https://github.com/rust-lang/rust/pull/127672)
- [Stabilize `&raw const` and `&raw mut` operators (RFC 2582)](https://github.com/rust-lang/rust/pull/127679)
- [Stabilize unsafe extern blocks (RFC 3484)](https://github.com/rust-lang/rust/pull/127921)
- [Stabilize nested field access in `offset_of!`](https://github.com/rust-lang/rust/pull/128284)
- [Do not require `T` to be live when dropping `[T; 0]`](https://github.com/rust-lang/rust/pull/128438)
- [Stabilize `const` operands in inline assembly](https://github.com/rust-lang/rust/pull/128570)
- [Stabilize floating-point arithmetic in `const fn`](https://github.com/rust-lang/rust/pull/128596)
- [Stabilize explicit opt-in to unsafe attributes](https://github.com/rust-lang/rust/pull/128771)
- [Document NaN bit patterns guarantees](https://github.com/rust-lang/rust/pull/129559)
Compiler
--------
- [Promote riscv64gc-unknown-linux-musl to tier 2](https://github.com/rust-lang/rust/pull/122049)
- [Promote Mac Catalyst targets `aarch64-apple-ios-macabi` and `x86_64-apple-ios-macabi` to Tier 2, and ship them with rustup](https://github.com/rust-lang/rust/pull/126450)
- [Add tier 3 NuttX based targets for RISC-V and ARM](https://github.com/rust-lang/rust/pull/127755)
- [Add tier 3 powerpc-unknown-linux-muslspe target](https://github.com/rust-lang/rust/pull/127905)
- [Improved diagnostics to explain why a pattern is unreachable](https://github.com/rust-lang/rust/pull/128034)
- [The compiler now triggers the unreachable code warning properly for async functions that don't return/are `-> !`](https://github.com/rust-lang/rust/pull/128443)
- [Promote `aarch64-apple-darwin` to Tier 1](https://github.com/rust-lang/rust/pull/128592)
- [Add Trusty OS target `aarch64-unknown-trusty` and `armv7-unknown-trusty` as tier 3 targets](https://github.com/rust-lang/rust/pull/129490)
- [Promote `wasm32-wasip2` to Tier 2.](https://github.com/rust-lang/rust/pull/126967/)
Libraries
---------
- [Generalize `{Rc,Arc}::make_mut()` to `Path`, `OsStr`, and `CStr`.](https://github.com/rust-lang/rust/pull/126877)
Stabilized APIs
---------------
- [`std::thread::Builder::spawn_unchecked`](https://doc.rust-lang.org/stable/std/thread/struct.Builder.html#method.spawn_unchecked)
- [`std::str::CharIndices::offset`](https://doc.rust-lang.org/nightly/std/str/struct.CharIndices.html#method.offset)
- [`std::option::Option::is_none_or`](https://doc.rust-lang.org/nightly/std/option/enum.Option.html#method.is_none_or)
- [`[T]::is_sorted`](https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.is_sorted)
- [`[T]::is_sorted_by`](https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.is_sorted_by)
- [`[T]::is_sorted_by_key`](https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.is_sorted_by_key)
- [`Iterator::is_sorted`](https://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.is_sorted)
- [`Iterator::is_sorted_by`](https://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.is_sorted_by)
- [`Iterator::is_sorted_by_key`](https://doc.rust-lang.org/nightly/std/iter/trait.Iterator.html#method.is_sorted_by_key)
- [`std::future::Ready::into_inner`](https://doc.rust-lang.org/nightly/std/future/struct.Ready.html#method.into_inner)
- [`std::iter::repeat_n`](https://doc.rust-lang.org/nightly/std/iter/fn.repeat_n.html)
- [`impl DoubleEndedIterator for Take>`](https://doc.rust-lang.org/nightly/std/iter/struct.Take.html#impl-DoubleEndedIterator-for-Take%3CRepeat%3CT%3E%3E)
- [`impl ExactSizeIterator for Take>`](https://doc.rust-lang.org/nightly/std/iter/struct.Take.html#impl-ExactSizeIterator-for-Take%3CRepeat%3CT%3E%3E)
- [`impl ExactSizeIterator for Take>`](https://doc.rust-lang.org/nightly/std/iter/struct.Take.html#impl-ExactSizeIterator-for-Take%3CRepeatWith%3CF%3E%3E)
- [`impl Default for std::collections::binary_heap::Iter`](https://doc.rust-lang.org/nightly/std/collections/binary_heap/struct.Iter.html#impl-Default-for-Iter%3C'_,+T%3E)
- [`impl Default for std::collections::btree_map::RangeMut`](https://doc.rust-lang.org/nightly/std/collections/btree_map/struct.RangeMut.html#impl-Default-for-RangeMut%3C'_,+K,+V%3E)
- [`impl Default for std::collections::btree_map::ValuesMut`](https://doc.rust-lang.org/nightly/std/collections/btree_map/struct.ValuesMut.html#impl-Default-for-ValuesMut%3C'_,+K,+V%3E)
- [`impl Default for std::collections::vec_deque::Iter`](https://doc.rust-lang.org/nightly/std/collections/vec_deque/struct.Iter.html#impl-Default-for-Iter%3C'_,+T%3E)
- [`impl Default for std::collections::vec_deque::IterMut`](https://doc.rust-lang.org/nightly/std/collections/vec_deque/struct.IterMut.html#impl-Default-for-IterMut%3C'_,+T%3E)
- [`Rc::new_uninit`](https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html#method.new_uninit)
- [`Rc>::assume_init`](https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html#method.assume_init)
- [`Rc<[T]>::new_uninit_slice`](https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html#method.new_uninit_slice)
- [`Rc<[MaybeUninit]>::assume_init`](https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html#method.assume_init-1)
- [`Arc::new_uninit`](https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.new_uninit)
- [`Arc>::assume_init`](https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.assume_init)
- [`Arc<[T]>::new_uninit_slice`](https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.new_uninit_slice)
- [`Arc<[MaybeUninit]>::assume_init`](https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.assume_init-1)
- [`Box::new_uninit`](https://doc.rust-lang.org/nightly/std/boxed/struct.Box.html#method.new_uninit)
- [`Box>::assume_init`](https://doc.rust-lang.org/nightly/std/boxed/struct.Box.html#method.assume_init)
- [`Box<[T]>::new_uninit_slice`](https://doc.rust-lang.org/nightly/std/boxed/struct.Box.html#method.new_uninit_slice)
- [`Box<[MaybeUninit]>::assume_init`](https://doc.rust-lang.org/nightly/std/boxed/struct.Box.html#method.assume_init-1)
- [`core::arch::x86_64::_bextri_u64`](https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bextri_u64.html)
- [`core::arch::x86_64::_bextri_u32`](https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bextri_u32.html)
- [`core::arch::x86::_mm_broadcastsi128_si256`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_broadcastsi128_si256.html)
- [`core::arch::x86::_mm256_stream_load_si256`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm256_stream_load_si256.html)
- [`core::arch::x86::_tzcnt_u16`](https://doc.rust-lang.org/stable/core/arch/x86/fn._tzcnt_u16.html)
- [`core::arch::x86::_mm_extracti_si64`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_extracti_si64.html)
- [`core::arch::x86::_mm_inserti_si64`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_inserti_si64.html)
- [`core::arch::x86::_mm_storeu_si16`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_storeu_si16.html)
- [`core::arch::x86::_mm_storeu_si32`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_storeu_si32.html)
- [`core::arch::x86::_mm_storeu_si64`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_storeu_si64.html)
- [`core::arch::x86::_mm_loadu_si16`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_loadu_si16.html)
- [`core::arch::x86::_mm_loadu_si32`](https://doc.rust-lang.org/stable/core/arch/x86/fn._mm_loadu_si32.html)
- [`core::arch::wasm32::u8x16_relaxed_swizzle`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u8x16_relaxed_swizzle.html)
- [`core::arch::wasm32::i8x16_relaxed_swizzle`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i8x16_relaxed_swizzle.html)
- [`core::arch::wasm32::i32x4_relaxed_trunc_f32x4`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i32x4_relaxed_trunc_f32x4.html)
- [`core::arch::wasm32::u32x4_relaxed_trunc_f32x4`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u32x4_relaxed_trunc_f32x4.html)
- [`core::arch::wasm32::i32x4_relaxed_trunc_f64x2_zero`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i32x4_relaxed_trunc_f64x2_zero.html)
- [`core::arch::wasm32::u32x4_relaxed_trunc_f64x2_zero`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u32x4_relaxed_trunc_f64x2_zero.html)
- [`core::arch::wasm32::f32x4_relaxed_madd`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f32x4_relaxed_madd.html)
- [`core::arch::wasm32::f32x4_relaxed_nmadd`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f32x4_relaxed_nmadd.html)
- [`core::arch::wasm32::f64x2_relaxed_madd`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f64x2_relaxed_madd.html)
- [`core::arch::wasm32::f64x2_relaxed_nmadd`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f64x2_relaxed_nmadd.html)
- [`core::arch::wasm32::i8x16_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i8x16_relaxed_laneselect.html)
- [`core::arch::wasm32::u8x16_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u8x16_relaxed_laneselect.html)
- [`core::arch::wasm32::i16x8_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i16x8_relaxed_laneselect.html)
- [`core::arch::wasm32::u16x8_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u16x8_relaxed_laneselect.html)
- [`core::arch::wasm32::i32x4_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i32x4_relaxed_laneselect.html)
- [`core::arch::wasm32::u32x4_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u32x4_relaxed_laneselect.html)
- [`core::arch::wasm32::i64x2_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i64x2_relaxed_laneselect.html)
- [`core::arch::wasm32::u64x2_relaxed_laneselect`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u64x2_relaxed_laneselect.html)
- [`core::arch::wasm32::f32x4_relaxed_min`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f32x4_relaxed_min.html)
- [`core::arch::wasm32::f32x4_relaxed_max`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f32x4_relaxed_max.html)
- [`core::arch::wasm32::f64x2_relaxed_min`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f64x2_relaxed_min.html)
- [`core::arch::wasm32::f64x2_relaxed_max`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.f64x2_relaxed_max.html)
- [`core::arch::wasm32::i16x8_relaxed_q15mulr`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i16x8_relaxed_q15mulr.html)
- [`core::arch::wasm32::u16x8_relaxed_q15mulr`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u16x8_relaxed_q15mulr.html)
- [`core::arch::wasm32::i16x8_relaxed_dot_i8x16_i7x16`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i16x8_relaxed_dot_i8x16_i7x16.html)
- [`core::arch::wasm32::u16x8_relaxed_dot_i8x16_i7x16`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u16x8_relaxed_dot_i8x16_i7x16.html)
- [`core::arch::wasm32::i32x4_relaxed_dot_i8x16_i7x16_add`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.i32x4_relaxed_dot_i8x16_i7x16_add.html)
- [`core::arch::wasm32::u32x4_relaxed_dot_i8x16_i7x16_add`](https://doc.rust-lang.org/nightly/core/arch/wasm32/fn.u32x4_relaxed_dot_i8x16_i7x16_add.html)
These APIs are now stable in const contexts:
- [`std::task::Waker::from_raw`](https://doc.rust-lang.org/nightly/std/task/struct.Waker.html#method.from_raw)
- [`std::task::Context::from_waker`](https://doc.rust-lang.org/nightly/std/task/struct.Context.html#method.from_waker)
- [`std::task::Context::waker`](https://doc.rust-lang.org/nightly/std/task/struct.Context.html#method.waker)
- [`{integer}::from_str_radix`](https://doc.rust-lang.org/nightly/std/primitive.u32.html#method.from_str_radix)
- [`std::num::ParseIntError::kind`](https://doc.rust-lang.org/nightly/std/num/struct.ParseIntError.html#method.kind)
Cargo
-----
- [feat: Add `info` cargo subcommand](https://github.com/rust-lang/cargo/pull/14141/)
Compatibility Notes
-------------------
- We now [disallow setting some built-in cfgs via the command-line](https://github.com/rust-lang/rust/pull/126158) with the newly added [`explicit_builtin_cfgs_in_flags`](https://doc.rust-lang.org/rustc/lints/listing/deny-by-default.html#explicit-builtin-cfgs-in-flags) lint in order to prevent incoherent state, eg. `windows` cfg active but target is Linux based. The appropriate [`rustc` flag](https://doc.rust-lang.org/rustc/command-line-arguments.html) should be used instead.
- The standard library has a new implementation of `binary_search` which significantly improves performance ([#128254](https://github.com/rust-lang/rust/pull/128254)). However when a sorted slice has multiple values which compare equal, the new implementation may select a different value among the equal ones than the old implementation.
- [illumos/Solaris now sets `MSG_NOSIGNAL` when writing to sockets](https://github.com/rust-lang/rust/pull/128259). This avoids killing the process with SIGPIPE when writing to a closed socket, which matches the existing behavior on other UNIX targets.
- [Removes a problematic hack that always passed the --whole-archive linker flag for tests, which may cause linker errors for code accidentally relying on it.](https://github.com/rust-lang/rust/pull/128400)
- The WebAssembly target features `multivalue` and `reference-types` are now
both enabled by default. These two features both have subtle changes implied
for generated WebAssembly binaries. For the `multivalue` feature, WebAssembly
target support has changed when upgrading to LLVM 19. Support for generating
functions with multiple returns no longer works and
`-Ctarget-feature=+multivalue` has a different meaning than it did in LLVM 18
and prior. There is no longer any supported means to generate a module that has
a function with multiple returns in WebAssembly from Rust source code. For the
`reference-types` feature the encoding of immediates in the `call_indirect`, a
commonly used instruction by the WebAssembly backend, has changed. Validators
and parsers which don't understand the `reference-types` proposal will no
longer accept modules produced by LLVM due to this change in encoding of
immediates. Additionally these features being enabled are encoded in the
`target_features` custom section and may affect downstream tooling such as
`wasm-opt` consuming the module. Generating a WebAssembly module that disables
default features requires `-Zbuild-std` support from Cargo and more information
can be found at
[rust-lang/rust#128511](https://github.com/rust-lang/rust/pull/128511).
- [Rust now raises unsafety errors for union patterns in parameter-position](https://github.com/rust-lang/rust/pull/130531)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Update to LLVM 19](https://github.com/rust-lang/rust/pull/127513)
Version 1.81.0 (2024-09-05)
==========================
Language
--------
- [Abort on uncaught panics in `extern "C"` functions.](https://github.com/rust-lang/rust/pull/116088/)
- [Fix ambiguous cases of multiple `&` in elided self lifetimes.](https://github.com/rust-lang/rust/pull/117967/)
- [Stabilize `#[expect]` for lints (RFC 2383),](https://github.com/rust-lang/rust/pull/120924/) like `#[allow]` with a warning if the lint is _not_ fulfilled.
- [Change method resolution to constrain hidden types instead of rejecting method candidates.](https://github.com/rust-lang/rust/pull/123962/)
- [Bump `elided_lifetimes_in_associated_constant` to deny.](https://github.com/rust-lang/rust/pull/124211/)
- [`offset_from`: always allow pointers to point to the same address.](https://github.com/rust-lang/rust/pull/124921/)
- [Allow constraining opaque types during subtyping in the trait system.](https://github.com/rust-lang/rust/pull/125447/)
- [Allow constraining opaque types during various unsizing casts.](https://github.com/rust-lang/rust/pull/125610/)
- [Deny keyword lifetimes pre-expansion.](https://github.com/rust-lang/rust/pull/126762/)
Compiler
--------
- [Make casts of pointers to trait objects stricter.](https://github.com/rust-lang/rust/pull/120248/)
- [Check alias args for well-formedness even if they have escaping bound vars.](https://github.com/rust-lang/rust/pull/123737/)
- [Deprecate no-op codegen option `-Cinline-threshold=...`.](https://github.com/rust-lang/rust/pull/124712/)
- [Re-implement a type-size based limit.](https://github.com/rust-lang/rust/pull/125507/)
- [Properly account for alignment in `transmute` size checks.](https://github.com/rust-lang/rust/pull/125740/)
- [Remove the `box_pointers` lint.](https://github.com/rust-lang/rust/pull/126018/)
- [Ensure the interpreter checks bool/char for validity when they are used in a cast.](https://github.com/rust-lang/rust/pull/126265/)
- [Improve coverage instrumentation for functions containing nested items.](https://github.com/rust-lang/rust/pull/127199/)
- Target changes:
- [Add Tier 3 `no_std` Xtensa targets:](https://github.com/rust-lang/rust/pull/125141/) `xtensa-esp32-none-elf`, `xtensa-esp32s2-none-elf`, `xtensa-esp32s3-none-elf`
- [Add Tier 3 `std` Xtensa targets:](https://github.com/rust-lang/rust/pull/126380/) `xtensa-esp32-espidf`, `xtensa-esp32s2-espidf`, `xtensa-esp32s3-espidf`
- [Add Tier 3 i686 Redox OS target:](https://github.com/rust-lang/rust/pull/126192/) `i686-unknown-redox`
- [Promote `arm64ec-pc-windows-msvc` to Tier 2.](https://github.com/rust-lang/rust/pull/126039/)
- [Promote `loongarch64-unknown-linux-musl` to Tier 2 with host tools.](https://github.com/rust-lang/rust/pull/126298/)
- [Enable full tools and profiler for LoongArch Linux targets.](https://github.com/rust-lang/rust/pull/127078/)
- [Unconditionally warn on usage of `wasm32-wasi`.](https://github.com/rust-lang/rust/pull/126662/) (see compatibility note below)
- Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support.
Libraries
---------
- [Split core's `PanicInfo` and std's `PanicInfo`.](https://github.com/rust-lang/rust/pull/115974/) (see compatibility note below)
- [Generalize `{Rc,Arc}::make_mut()` to unsized types.](https://github.com/rust-lang/rust/pull/116113/)
- [Replace sort implementations with stable `driftsort` and unstable `ipnsort`.](https://github.com/rust-lang/rust/pull/124032/) All `slice::sort*` and `slice::select_nth*` methods are expected to see significant performance improvements. See the [research project](https://github.com/Voultapher/sort-research-rs) for more details.
- [Document behavior of `create_dir_all` with respect to empty paths.](https://github.com/rust-lang/rust/pull/125112/)
- [Fix interleaved output in the default panic hook when multiple threads panic simultaneously.](https://github.com/rust-lang/rust/pull/127397/)
- Fix `Command`'s batch files argument escaping not working when file name has trailing whitespace or periods (CVE-2024-43402).
Stabilized APIs
---------------
- [`core::error`](https://doc.rust-lang.org/stable/core/error/index.html)
- [`hint::assert_unchecked`](https://doc.rust-lang.org/stable/core/hint/fn.assert_unchecked.html)
- [`fs::exists`](https://doc.rust-lang.org/stable/std/fs/fn.exists.html)
- [`AtomicBool::fetch_not`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicBool.html#method.fetch_not)
- [`Duration::abs_diff`](https://doc.rust-lang.org/stable/core/time/struct.Duration.html#method.abs_diff)
- [`IoSlice::advance`](https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance)
- [`IoSlice::advance_slices`](https://doc.rust-lang.org/stable/std/io/struct.IoSlice.html#method.advance_slices)
- [`IoSliceMut::advance`](https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance)
- [`IoSliceMut::advance_slices`](https://doc.rust-lang.org/stable/std/io/struct.IoSliceMut.html#method.advance_slices)
- [`PanicHookInfo`](https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html)
- [`PanicInfo::message`](https://doc.rust-lang.org/stable/core/panic/struct.PanicInfo.html#method.message)
- [`PanicMessage`](https://doc.rust-lang.org/stable/core/panic/struct.PanicMessage.html)
These APIs are now stable in const contexts:
- [`char::from_u32_unchecked`](https://doc.rust-lang.org/stable/core/char/fn.from_u32_unchecked.html) (function)
- [`char::from_u32_unchecked`](https://doc.rust-lang.org/stable/core/primitive.char.html#method.from_u32_unchecked) (method)
- [`CStr::count_bytes`](https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.count_bytes)
- [`CStr::from_ptr`](https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.from_ptr)
Cargo
-----
- [Generated `.cargo_vcs_info.json` is always included, even when `--allow-dirty` is passed.](https://github.com/rust-lang/cargo/pull/13960/)
- [Disallow `package.license-file` and `package.readme` pointing to non-existent files during packaging.](https://github.com/rust-lang/cargo/pull/13921/)
- [Disallow passing `--release`/`--debug` flag along with the `--profile` flag.](https://github.com/rust-lang/cargo/pull/13971/)
- [Remove `lib.plugin` key support in `Cargo.toml`. Rust plugin support has been deprecated for four years and was removed in 1.75.0.](https://github.com/rust-lang/cargo/pull/13902/)
Compatibility Notes
-------------------
* Usage of the `wasm32-wasi` target will now issue a compiler warning and request users switch to the `wasm32-wasip1` target instead. Both targets are the same, `wasm32-wasi` is only being renamed, and this [change to the WASI target](https://blog.rust-lang.org/2024/04/09/updates-to-rusts-wasi-targets.html) is being done to enable removing `wasm32-wasi` in January 2025.
* We have renamed `std::panic::PanicInfo` to `std::panic::PanicHookInfo`. The old name will continue to work as an alias, but will result in a deprecation warning starting in Rust 1.82.0.
`core::panic::PanicInfo` will remain unchanged, however, as this is now a *different type*.
The reason is that these types have different roles: `std::panic::PanicHookInfo` is the argument to the [panic hook](https://doc.rust-lang.org/stable/std/panic/fn.set_hook.html) in std context (where panics can have an arbitrary payload), while `core::panic::PanicInfo` is the argument to the [`#[panic_handler]`](https://doc.rust-lang.org/nomicon/panic-handler.html) in no_std context (where panics always carry a formatted *message*). Separating these types allows us to add more useful methods to these types, such as `std::panic::PanicHookInfo::payload_as_str()` and `core::panic::PanicInfo::message()`.
* The new sort implementations may panic if a type's implementation of [`Ord`](https://doc.rust-lang.org/std/cmp/trait.Ord.html) (or the given comparison function) does not implement a [total order](https://en.wikipedia.org/wiki/Total_order) as the trait requires. `Ord`'s supertraits (`PartialOrd`, `Eq`, and `PartialEq`) must also be consistent. The previous implementations would not "notice" any problem, but the new implementations have a good chance of detecting inconsistencies, throwing a panic rather than returning knowingly unsorted data.
* [In very rare cases, a change in the internal evaluation order of the trait
solver may result in new fatal overflow errors.](https://github.com/rust-lang/rust/pull/126128)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Add a Rust-for-Linux `auto` CI job to check kernel builds.](https://github.com/rust-lang/rust/pull/125209/)
Version 1.80.1 (2024-08-08)
===========================
- [Fix miscompilation in the jump threading MIR optimization when comparing floats](https://github.com/rust-lang/rust/pull/128271)
- [Revert changes to the `dead_code` lint from 1.80.0](https://github.com/rust-lang/rust/pull/128618)
Version 1.80.0 (2024-07-25)
==========================
Language
--------
- [Document maximum allocation size](https://github.com/rust-lang/rust/pull/116675/)
- [Allow zero-byte offsets and ZST read/writes on arbitrary pointers](https://github.com/rust-lang/rust/pull/117329/)
- [Support C23's variadics without a named parameter](https://github.com/rust-lang/rust/pull/124048/)
- [Stabilize `exclusive_range_pattern` feature](https://github.com/rust-lang/rust/pull/124459/)
- [Guarantee layout and ABI of `Result` in some scenarios](https://github.com/rust-lang/rust/pull/124870)
Compiler
--------
- [Update cc crate to v1.0.97 allowing additional spectre mitigations on MSVC targets](https://github.com/rust-lang/rust/pull/124892/)
- [Allow field reordering on types marked `repr(packed(1))`](https://github.com/rust-lang/rust/pull/125360/)
- [Add a lint against never type fallback affecting unsafe code](https://github.com/rust-lang/rust/pull/123939/)
- [Disallow cast with trailing braced macro in let-else](https://github.com/rust-lang/rust/pull/125049/)
- [Expand `for_loops_over_fallibles` lint to lint on fallibles behind references.](https://github.com/rust-lang/rust/pull/125156/)
- [self-contained linker: retry linking without `-fuse-ld=lld` on CCs that don't support it](https://github.com/rust-lang/rust/pull/125417/)
- [Do not parse CVarArgs (`...`) as a type in trait bounds](https://github.com/rust-lang/rust/pull/125863/)
- Improvements to LLDB formatting [#124458](https://github.com/rust-lang/rust/pull/124458) [#124500](https://github.com/rust-lang/rust/pull/124500)
- [For the wasm32-wasip2 target default to PIC and do not use `-fuse-ld=lld`](https://github.com/rust-lang/rust/pull/124858/)
- [Add x86_64-unknown-linux-none as a tier 3 target](https://github.com/rust-lang/rust/pull/125023/)
- [Lint on `foo.into_iter()` resolving to `&Box<[T]>: IntoIterator`](https://github.com/rust-lang/rust/pull/124097/)
Libraries
---------
- [Add `size_of` and `size_of_val` and `align_of` and `align_of_val` to the prelude](https://github.com/rust-lang/rust/pull/123168/)
- [Abort a process when FD ownership is violated](https://github.com/rust-lang/rust/pull/124210/)
- [io::Write::write_fmt: panic if the formatter fails when the stream does not fail](https://github.com/rust-lang/rust/pull/125012/)
- [Panic if `PathBuf::set_extension` would add a path separator](https://github.com/rust-lang/rust/pull/125070/)
- [Add assert_unsafe_precondition to unchecked_{add,sub,neg,mul,shl,shr} methods](https://github.com/rust-lang/rust/pull/121571/)
- [Update `c_char` on AIX to use the correct type](https://github.com/rust-lang/rust/pull/122986/)
- [`offset_of!` no longer returns a temporary](https://github.com/rust-lang/rust/pull/124484/)
- [Handle sigma in `str.to_lowercase` correctly](https://github.com/rust-lang/rust/pull/124773/)
- [Raise `DEFAULT_MIN_STACK_SIZE` to at least 64KiB](https://github.com/rust-lang/rust/pull/126059/)
Stabilized APIs
---------------
- [`impl Default for Rc`](https://doc.rust-lang.org/beta/alloc/rc/struct.Rc.html#impl-Default-for-Rc%3CCStr%3E)
- [`impl Default for Rc`](https://doc.rust-lang.org/beta/alloc/rc/struct.Rc.html#impl-Default-for-Rc%3Cstr%3E)
- [`impl Default for Rc<[T]>`](https://doc.rust-lang.org/beta/alloc/rc/struct.Rc.html#impl-Default-for-Rc%3C%5BT%5D%3E)
- [`impl Default for Arc`](https://doc.rust-lang.org/beta/alloc/sync/struct.Arc.html#impl-Default-for-Arc%3Cstr%3E)
- [`impl Default for Arc`](https://doc.rust-lang.org/beta/alloc/sync/struct.Arc.html#impl-Default-for-Arc%3CCStr%3E)
- [`impl Default for Arc<[T]>`](https://doc.rust-lang.org/beta/alloc/sync/struct.Arc.html#impl-Default-for-Arc%3C%5BT%5D%3E)
- [`impl IntoIterator for Box<[T]>`](https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html#impl-IntoIterator-for-Box%3C%5BI%5D,+A%3E)
- [`impl FromIterator for Box`](https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html#impl-FromIterator%3CString%3E-for-Box%3Cstr%3E)
- [`impl FromIterator for Box`](https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html#impl-FromIterator%3Cchar%3E-for-Box%3Cstr%3E)
- [`LazyCell`](https://doc.rust-lang.org/beta/core/cell/struct.LazyCell.html)
- [`LazyLock`](https://doc.rust-lang.org/beta/std/sync/struct.LazyLock.html)
- [`Duration::div_duration_f32`](https://doc.rust-lang.org/beta/std/time/struct.Duration.html#method.div_duration_f32)
- [`Duration::div_duration_f64`](https://doc.rust-lang.org/beta/std/time/struct.Duration.html#method.div_duration_f64)
- [`Option::take_if`](https://doc.rust-lang.org/beta/std/option/enum.Option.html#method.take_if)
- [`Seek::seek_relative`](https://doc.rust-lang.org/beta/std/io/trait.Seek.html#method.seek_relative)
- [`BinaryHeap::as_slice`](https://doc.rust-lang.org/beta/std/collections/struct.BinaryHeap.html#method.as_slice)
- [`NonNull::offset`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.offset)
- [`NonNull::byte_offset`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_offset)
- [`NonNull::add`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.add)
- [`NonNull::byte_add`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_add)
- [`NonNull::sub`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.sub)
- [`NonNull::byte_sub`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_sub)
- [`NonNull::offset_from`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.offset_from)
- [`NonNull::byte_offset_from`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.byte_offset_from)
- [`NonNull::read`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.read)
- [`NonNull::read_volatile`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.read_volatile)
- [`NonNull::read_unaligned`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.read_unaligned)
- [`NonNull::write`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write)
- [`NonNull::write_volatile`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write_volatile)
- [`NonNull::write_unaligned`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write_unaligned)
- [`NonNull::write_bytes`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.write_bytes)
- [`NonNull::copy_to`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_to)
- [`NonNull::copy_to_nonoverlapping`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_to_nonoverlapping)
- [`NonNull::copy_from`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_from)
- [`NonNull::copy_from_nonoverlapping`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.copy_from_nonoverlapping)
- [`NonNull::replace`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.replace)
- [`NonNull::swap`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.swap)
- [`NonNull::drop_in_place`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.drop_in_place)
- [`NonNull::align_offset`](https://doc.rust-lang.org/beta/std/ptr/struct.NonNull.html#method.align_offset)
- [`<[T]>::split_at_checked`](https://doc.rust-lang.org/beta/std/primitive.slice.html#method.split_at_checked)
- [`<[T]>::split_at_mut_checked`](https://doc.rust-lang.org/beta/std/primitive.slice.html#method.split_at_mut_checked)
- [`str::split_at_checked`](https://doc.rust-lang.org/beta/std/primitive.str.html#method.split_at_checked)
- [`str::split_at_mut_checked`](https://doc.rust-lang.org/beta/std/primitive.str.html#method.split_at_mut_checked)
- [`str::trim_ascii`](https://doc.rust-lang.org/beta/std/primitive.str.html#method.trim_ascii)
- [`str::trim_ascii_start`](https://doc.rust-lang.org/beta/std/primitive.str.html#method.trim_ascii_start)
- [`str::trim_ascii_end`](https://doc.rust-lang.org/beta/std/primitive.str.html#method.trim_ascii_end)
- [`<[u8]>::trim_ascii`](https://doc.rust-lang.org/beta/core/primitive.slice.html#method.trim_ascii)
- [`<[u8]>::trim_ascii_start`](https://doc.rust-lang.org/beta/core/primitive.slice.html#method.trim_ascii_start)
- [`<[u8]>::trim_ascii_end`](https://doc.rust-lang.org/beta/core/primitive.slice.html#method.trim_ascii_end)
- [`Ipv4Addr::BITS`](https://doc.rust-lang.org/beta/core/net/struct.Ipv4Addr.html#associatedconstant.BITS)
- [`Ipv4Addr::to_bits`](https://doc.rust-lang.org/beta/core/net/struct.Ipv4Addr.html#method.to_bits)
- [`Ipv4Addr::from_bits`](https://doc.rust-lang.org/beta/core/net/struct.Ipv4Addr.html#method.from_bits)
- [`Ipv6Addr::BITS`](https://doc.rust-lang.org/beta/core/net/struct.Ipv6Addr.html#associatedconstant.BITS)
- [`Ipv6Addr::to_bits`](https://doc.rust-lang.org/beta/core/net/struct.Ipv6Addr.html#method.to_bits)
- [`Ipv6Addr::from_bits`](https://doc.rust-lang.org/beta/core/net/struct.Ipv6Addr.html#method.from_bits)
- [`Vec::<[T; N]>::into_flattened`](https://doc.rust-lang.org/beta/alloc/vec/struct.Vec.html#method.into_flattened)
- [`<[[T; N]]>::as_flattened`](https://doc.rust-lang.org/beta/core/primitive.slice.html#method.as_flattened)
- [`<[[T; N]]>::as_flattened_mut`](https://doc.rust-lang.org/beta/core/primitive.slice.html#method.as_flattened_mut)
These APIs are now stable in const contexts:
- [`<[T]>::last_chunk`](https://doc.rust-lang.org/beta/core/primitive.slice.html#method.last_chunk)
- [`BinaryHeap::new`](https://doc.rust-lang.org/beta/std/collections/struct.BinaryHeap.html#method.new)
Cargo
-----
- [Stabilize `-Zcheck-cfg` as always enabled](https://github.com/rust-lang/cargo/pull/13571/)
- [Warn, rather than fail publish, if a target is excluded](https://github.com/rust-lang/cargo/pull/13713/)
- [Add special `check-cfg` lint config for the `unexpected_cfgs` lint](https://github.com/rust-lang/cargo/pull/13913/)
- [Stabilize `cargo update --precise `](https://github.com/rust-lang/cargo/pull/13974/)
- [Don't change file permissions on `Cargo.toml` when using `cargo add`](https://github.com/rust-lang/cargo/pull/13898/)
- [Support using `cargo fix` on IPv6-only networks](https://github.com/rust-lang/cargo/pull/13907/)
Rustdoc
-----
- [Allow searching for references](https://github.com/rust-lang/rust/pull/124148/)
- [Stabilize `custom_code_classes_in_docs` feature](https://github.com/rust-lang/rust/pull/124577/)
- [fix: In cross-crate scenarios show enum variants on type aliases of enums](https://github.com/rust-lang/rust/pull/125300/)
Compatibility Notes
-------------------
- [rustfmt estimates line lengths differently when using non-ascii characters](https://github.com/rust-lang/rustfmt/issues/6203)
- [Type aliases are now handled correctly in orphan check](https://github.com/rust-lang/rust/pull/117164/)
- [Allow instructing rustdoc to read from stdin via `-`](https://github.com/rust-lang/rust/pull/124611/)
- [`std::env::{set_var, remove_var}` can no longer be converted to safe function pointers and no longer implement the `Fn` family of traits](https://github.com/rust-lang/rust/pull/124636)
- [Warn (or error) when `Self` constructor from outer item is referenced in inner nested item](https://github.com/rust-lang/rust/pull/124187/)
- [Turn `indirect_structural_match` and `pointer_structural_match` lints into hard errors](https://github.com/rust-lang/rust/pull/124661/)
- [Make `where_clause_object_safety` lint a regular object safety violation](https://github.com/rust-lang/rust/pull/125380/)
- [Turn `proc_macro_back_compat` lint into a hard error.](https://github.com/rust-lang/rust/pull/125596/)
- [Detect unused structs even when implementing private traits](https://github.com/rust-lang/rust/pull/122382/)
- [`std::sync::ReentrantLockGuard` is no longer `Sync` if `T: !Sync`](https://github.com/rust-lang/rust/pull/125527) which means [`std::io::StdoutLock` and `std::io::StderrLock` are no longer Sync](https://github.com/rust-lang/rust/issues/127340)
- [Type inference will fail in some cases due to new implementations of `FromIterator for Box`.](https://github.com/rust-lang/rust/pull/99969/)
Notably, this breaks versions of the `time` crate before 0.3.35, due to no longer inferring the implementation for `Box<[_]>`.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- Misc improvements to size of generated html by rustdoc e.g. [#124738](https://github.com/rust-lang/rust/pull/124738/) and [#123734](https://github.com/rust-lang/rust/pull/123734/)
- [MSVC targets no longer depend on libc](https://github.com/rust-lang/rust/pull/124050/)
Version 1.79.0 (2024-06-13)
==========================
Language
--------
- [Stabilize inline `const {}` expressions.](https://github.com/rust-lang/rust/pull/104087/)
- [Prevent opaque types being instantiated twice with different regions within the same function.](https://github.com/rust-lang/rust/pull/116935/)
- [Stabilize WebAssembly target features that are in phase 4 and 5.](https://github.com/rust-lang/rust/pull/117457/)
- [Add the `redundant_lifetimes` lint to detect lifetimes which are semantically redundant.](https://github.com/rust-lang/rust/pull/118391/)
- [Stabilize the `unnameable_types` lint for public types that can't be named.](https://github.com/rust-lang/rust/pull/120144/)
- [Enable debuginfo in macros, and stabilize `-C collapse-macro-debuginfo` and `#[collapse_debuginfo]`.](https://github.com/rust-lang/rust/pull/120845/)
- [Propagate temporary lifetime extension into `if` and `match` expressions.](https://github.com/rust-lang/rust/pull/121346/)
- [Restrict promotion of `const fn` calls.](https://github.com/rust-lang/rust/pull/121557/)
- [Warn against refining impls of crate-private traits with `refining_impl_trait` lint.](https://github.com/rust-lang/rust/pull/121720/)
- [Stabilize associated type bounds (RFC 2289).](https://github.com/rust-lang/rust/pull/122055/)
- [Stabilize importing `main` from other modules or crates.](https://github.com/rust-lang/rust/pull/122060/)
- [Check return types of function types for well-formedness](https://github.com/rust-lang/rust/pull/115538)
- [Rework `impl Trait` lifetime inference](https://github.com/rust-lang/rust/pull/116891/)
- [Change inductive trait solver cycles to be ambiguous](https://github.com/rust-lang/rust/pull/122791)
Compiler
--------
- [Define `-C strip` to only affect binaries, not artifacts like `.pdb`.](https://github.com/rust-lang/rust/pull/115120/)
- [Stabilize `-Crelro-level` for controlling runtime link hardening.](https://github.com/rust-lang/rust/pull/121694/)
- [Stabilize checking of `cfg` names and values at compile-time with `--check-cfg`.](https://github.com/rust-lang/rust/pull/123501/)
*Note that this only stabilizes the compiler part, the Cargo part is still unstable in this release.*
- [Add `aarch64-apple-visionos` and `aarch64-apple-visionos-sim` tier 3 targets.](https://github.com/rust-lang/rust/pull/121419/)
- [Add `riscv32ima-unknown-none-elf` tier 3 target.](https://github.com/rust-lang/rust/pull/122696/)
- [Promote several Windows targets to tier 2](https://github.com/rust-lang/rust/pull/121712): `aarch64-pc-windows-gnullvm`, `i686-pc-windows-gnullvm`, and `x86_64-pc-windows-gnullvm`.
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Implement `FromIterator` for `(impl Default + Extend, impl Default + Extend)`.](https://github.com/rust-lang/rust/pull/107462/)
- [Implement `{Div,Rem}Assign>` on `X`.](https://github.com/rust-lang/rust/pull/121952/)
- [Document overrides of `clone_from()` in core/std.](https://github.com/rust-lang/rust/pull/122201/)
- [Link MSVC default lib in core.](https://github.com/rust-lang/rust/pull/122268/)
- [Caution against using `transmute` between pointers and integers.](https://github.com/rust-lang/rust/pull/122379/)
- [Enable frame pointers for the standard library.](https://github.com/rust-lang/rust/pull/122646/)
Stabilized APIs
---------------
- [`{integer}::unchecked_add`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.unchecked_add)
- [`{integer}::unchecked_mul`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.unchecked_mul)
- [`{integer}::unchecked_sub`](https://doc.rust-lang.org/stable/core/primitive.i32.html#method.unchecked_sub)
- [`<[T]>::split_at_unchecked`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_unchecked)
- [`<[T]>::split_at_mut_unchecked`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.split_at_mut_unchecked)
- [`<[u8]>::utf8_chunks`](https://doc.rust-lang.org/stable/core/primitive.slice.html#method.utf8_chunks)
- [`str::Utf8Chunks`](https://doc.rust-lang.org/stable/core/str/struct.Utf8Chunks.html)
- [`str::Utf8Chunk`](https://doc.rust-lang.org/stable/core/str/struct.Utf8Chunk.html)
- [`<*const T>::is_aligned`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_aligned)
- [`<*mut T>::is_aligned`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_aligned-1)
- [`NonNull::is_aligned`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.is_aligned)
- [`<*const [T]>::len`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.len)
- [`<*mut [T]>::len`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.len-1)
- [`<*const [T]>::is_empty`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_empty)
- [`<*mut [T]>::is_empty`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.is_empty-1)
- [`NonNull::<[T]>::is_empty`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.is_empty)
- [`CStr::count_bytes`](https://doc.rust-lang.org/stable/core/ffi/c_str/struct.CStr.html#method.count_bytes)
- [`io::Error::downcast`](https://doc.rust-lang.org/stable/std/io/struct.Error.html#method.downcast)
- [`num::NonZero`](https://doc.rust-lang.org/stable/core/num/struct.NonZero.html)
- [`path::absolute`](https://doc.rust-lang.org/stable/std/path/fn.absolute.html)
- [`proc_macro::Literal::byte_character`](https://doc.rust-lang.org/stable/proc_macro/struct.Literal.html#method.byte_character)
- [`proc_macro::Literal::c_string`](https://doc.rust-lang.org/stable/proc_macro/struct.Literal.html#method.c_string)
These APIs are now stable in const contexts:
- [`Atomic*::into_inner`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.into_inner)
- [`io::Cursor::new`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.new)
- [`io::Cursor::get_ref`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.get_ref)
- [`io::Cursor::position`](https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.position)
- [`io::empty`](https://doc.rust-lang.org/stable/std/io/fn.empty.html)
- [`io::repeat`](https://doc.rust-lang.org/stable/std/io/fn.repeat.html)
- [`io::sink`](https://doc.rust-lang.org/stable/std/io/fn.sink.html)
- [`panic::Location::caller`](https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.caller)
- [`panic::Location::file`](https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.file)
- [`panic::Location::line`](https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.line)
- [`panic::Location::column`](https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.column)
Cargo
-----
- [Prevent dashes in `lib.name`, always normalizing to `_`.](https://github.com/rust-lang/cargo/pull/12783/)
- [Stabilize MSRV-aware version requirement selection in `cargo add`.](https://github.com/rust-lang/cargo/pull/13608/)
- [Switch to using `gitoxide` by default for listing files.](https://github.com/rust-lang/cargo/pull/13696/)
Rustdoc
-----
- [Always display stability version even if it's the same as the containing item.](https://github.com/rust-lang/rust/pull/118441/)
- [Show a single search result for items with multiple paths.](https://github.com/rust-lang/rust/pull/119912/)
- [Support typing `/` in docs to begin a search.](https://github.com/rust-lang/rust/pull/123355/)
Misc
----
Compatibility Notes
-------------------
- [Update the minimum external LLVM to 17.](https://github.com/rust-lang/rust/pull/122649/)
- [`RustcEncodable` and `RustcDecodable` are soft-destabilized, to be removed
from the prelude in next edition.](https://github.com/rust-lang/rust/pull/116016/)
- [The `wasm_c_abi` future-incompatibility lint will warn about use of the
non-spec-compliant C ABI.](https://github.com/rust-lang/rust/pull/117918/)
Use `wasm-bindgen v0.2.88` to generate forward-compatible bindings.
- [Check return types of function types for well-formedness](https://github.com/rust-lang/rust/pull/115538)
Version 1.78.0 (2024-05-02)
==========================
Language
--------
- [Stabilize `#[cfg(target_abi = ...)]`](https://github.com/rust-lang/rust/pull/119590/)
- [Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute](https://github.com/rust-lang/rust/pull/119888/)
- [Make async-fn-in-trait implementable with concrete signatures](https://github.com/rust-lang/rust/pull/120103/)
- [Make matching on NaN a hard error, and remove the rest of `illegal_floating_point_literal_pattern`](https://github.com/rust-lang/rust/pull/116284/)
- [static mut: allow mutable reference to arbitrary types, not just slices and arrays](https://github.com/rust-lang/rust/pull/117614/)
- [Extend `invalid_reference_casting` to include references casting to bigger memory layout](https://github.com/rust-lang/rust/pull/118983/)
- [Add `non_contiguous_range_endpoints` lint for singleton gaps after exclusive ranges](https://github.com/rust-lang/rust/pull/118879/)
- [Add `wasm_c_abi` lint for use of older wasm-bindgen versions](https://github.com/rust-lang/rust/pull/117918/)
This lint currently only works when using Cargo.
- [Update `indirect_structural_match` and `pointer_structural_match` lints to match RFC](https://github.com/rust-lang/rust/pull/120423/)
- [Make non-`PartialEq`-typed consts as patterns a hard error](https://github.com/rust-lang/rust/pull/120805/)
- [Split `refining_impl_trait` lint into `_reachable`, `_internal` variants](https://github.com/rust-lang/rust/pull/121720/)
- [Remove unnecessary type inference when using associated types inside of higher ranked `where`-bounds](https://github.com/rust-lang/rust/pull/119849)
- [Weaken eager detection of cyclic types during type inference](https://github.com/rust-lang/rust/pull/119989)
- [`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Trait + Auto`](https://github.com/rust-lang/rust/pull/119338)
Compiler
--------
- [Made `INVALID_DOC_ATTRIBUTES` lint deny by default](https://github.com/rust-lang/rust/pull/111505/)
- [Increase accuracy of redundant `use` checking](https://github.com/rust-lang/rust/pull/117772/)
- [Suggest moving definition if non-found macro_rules! is defined later](https://github.com/rust-lang/rust/pull/121130/)
- [Lower transmutes from int to pointer type as gep on null](https://github.com/rust-lang/rust/pull/121282/)
Target changes:
- [Windows tier 1 targets now require at least Windows 10](https://github.com/rust-lang/rust/pull/115141/)
- [Enable CMPXCHG16B, SSE3, SAHF/LAHF and 128-bit Atomics in tier 1 Windows](https://github.com/rust-lang/rust/pull/120820/)
- [Add `wasm32-wasip1` tier 2 (without host tools) target](https://github.com/rust-lang/rust/pull/120468/)
- [Add `wasm32-wasip2` tier 3 target](https://github.com/rust-lang/rust/pull/119616/)
- [Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`](https://github.com/rust-lang/rust/pull/122170/)
- [Add `arm64ec-pc-windows-msvc` tier 3 target](https://github.com/rust-lang/rust/pull/119199/)
- [Add `armv8r-none-eabihf` tier 3 target for the Cortex-R52](https://github.com/rust-lang/rust/pull/110482/)
- [Add `loongarch64-unknown-linux-musl` tier 3 target](https://github.com/rust-lang/rust/pull/121832/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Bump Unicode to version 15.1.0, regenerate tables](https://github.com/rust-lang/rust/pull/120777/)
- [Make align_offset, align_to well-behaved in all cases](https://github.com/rust-lang/rust/pull/121201/)
- [PartialEq, PartialOrd: document expectations for transitive chains](https://github.com/rust-lang/rust/pull/115386/)
- [Optimize away poison guards when std is built with panic=abort](https://github.com/rust-lang/rust/pull/100603/)
- [Replace pthread `RwLock` with custom implementation](https://github.com/rust-lang/rust/pull/110211/)
- [Implement unwind safety for Condvar on all platforms](https://github.com/rust-lang/rust/pull/121768/)
- [Add ASCII fast-path for `char::is_grapheme_extended`](https://github.com/rust-lang/rust/pull/121138/)
Stabilized APIs
---------------
- [`impl Read for &Stdin`](https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#impl-Read-for-%26Stdin)
- [Accept non `'static` lifetimes for several `std::error::Error` related implementations](https://github.com/rust-lang/rust/pull/113833/)
- [Make `impl` impl take `?Sized`](https://github.com/rust-lang/rust/pull/114655/)
- [`impl From for io::Error`](https://doc.rust-lang.org/stable/std/io/struct.Error.html#impl-From%3CTryReserveError%3E-for-Error)
These APIs are now stable in const contexts:
- [`Barrier::new()`](https://doc.rust-lang.org/stable/std/sync/struct.Barrier.html#method.new)
Cargo
-----
- [Stabilize lockfile v4](https://github.com/rust-lang/cargo/pull/12852/)
- [Respect `rust-version` when generating lockfile](https://github.com/rust-lang/cargo/pull/12861/)
- [Control `--charset` via auto-detecting config value](https://github.com/rust-lang/cargo/pull/13337/)
- [Support `target..rustdocflags` officially](https://github.com/rust-lang/cargo/pull/13197/)
- [Stabilize global cache data tracking](https://github.com/rust-lang/cargo/pull/13492/)
Compatibility Notes
-------------------
- [Many unsafe precondition checks now run for user code with debug assertions enabled](https://github.com/rust-lang/rust/pull/120594/)
This change helps users catch undefined behavior in their code, though the details of how much is checked are generally not stable.
- [riscv only supports split_debuginfo=off for now](https://github.com/rust-lang/rust/pull/120518/)
- [Consistently check bounds on hidden types of `impl Trait`](https://github.com/rust-lang/rust/pull/121679)
- [Change equality of higher ranked types to not rely on subtyping](https://github.com/rust-lang/rust/pull/118247)
- [When called, additionally check bounds on normalized function return type](https://github.com/rust-lang/rust/pull/118882)
- [Expand coverage for `arithmetic_overflow` lint](https://github.com/rust-lang/rust/pull/119432/)
- [Fix detection of potential interior mutability in `const` initializers](https://github.com/rust-lang/rust/issues/121250)
This code was accidentally accepted. The fix can break generic code that borrows a value of unknown type,
as there is currently no way to declare "this type has no interior mutability". In the future, stabilizing
the [`Freeze` trait](https://github.com/rust-lang/rust/issues/121675) will allow proper support for such code.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Update to LLVM 18](https://github.com/rust-lang/rust/pull/120055/)
- [Build `rustc` with 1CGU on `x86_64-pc-windows-msvc`](https://github.com/rust-lang/rust/pull/112267/)
- [Build `rustc` with 1CGU on `x86_64-apple-darwin`](https://github.com/rust-lang/rust/pull/112268/)
- [Introduce `run-make` V2 infrastructure, a `run_make_support` library and port over 2 tests as example](https://github.com/rust-lang/rust/pull/113026/)
- [Windows: Implement condvar, mutex and rwlock using futex](https://github.com/rust-lang/rust/pull/121956/)
Version 1.77.2 (2024-04-09)
===========================
- [CVE-2024-24576: fix escaping of Windows batch file arguments in `std::process::Command`](https://blog.rust-lang.org/2024/04/09/cve-2024-24576.html)
Version 1.77.1 (2024-03-28)
===========================
- [Revert stripping debuginfo by default for Windows](https://github.com/rust-lang/cargo/pull/13654)
This fixes a regression in 1.77 by reverting to the previous default.
Platforms other than Windows are not affected.
- Internal: [Fix heading anchor rendering in doc pages](https://github.com/rust-lang/rust/pull/122693)
Version 1.77.0 (2024-03-21)
==========================
Language
--------
- [Reveal opaque types within the defining body for exhaustiveness checking.](https://github.com/rust-lang/rust/pull/116821/)
- [Stabilize C-string literals.](https://github.com/rust-lang/rust/pull/117472/)
- [Stabilize THIR unsafeck.](https://github.com/rust-lang/rust/pull/117673/)
- [Add lint `static_mut_refs` to warn on references to mutable statics.](https://github.com/rust-lang/rust/pull/117556/)
- [Support async recursive calls (as long as they have indirection).](https://github.com/rust-lang/rust/pull/117703/)
- [Undeprecate lint `unstable_features` and make use of it in the compiler.](https://github.com/rust-lang/rust/pull/118639/)
- [Make inductive cycles in coherence ambiguous always.](https://github.com/rust-lang/rust/pull/118649/)
- [Get rid of type-driven traversal in const-eval interning](https://github.com/rust-lang/rust/pull/119044/),
only as a [future compatibility lint](https://github.com/rust-lang/rust/pull/122204) for now.
- [Deny braced macro invocations in let-else.](https://github.com/rust-lang/rust/pull/119062/)
Compiler
--------
- [Include lint `soft_unstable` in future breakage reports.](https://github.com/rust-lang/rust/pull/116274/)
- [Make `i128` and `u128` 16-byte aligned on x86-based targets.](https://github.com/rust-lang/rust/pull/116672/)
- [Use `--verbose` in diagnostic output.](https://github.com/rust-lang/rust/pull/119129/)
- [Improve spacing between printed tokens.](https://github.com/rust-lang/rust/pull/120227/)
- [Merge the `unused_tuple_struct_fields` lint into `dead_code`.](https://github.com/rust-lang/rust/pull/118297/)
- [Error on incorrect implied bounds in well-formedness check](https://github.com/rust-lang/rust/pull/118553/),
with a temporary exception for Bevy.
- [Fix coverage instrumentation/reports for non-ASCII source code.](https://github.com/rust-lang/rust/pull/119033/)
- [Fix `fn`/`const` items implied bounds and well-formedness check.](https://github.com/rust-lang/rust/pull/120019/)
- [Promote `riscv32{im|imafc}-unknown-none-elf` targets to tier 2.](https://github.com/rust-lang/rust/pull/118704/)
- Add several new tier 3 targets:
- [`aarch64-unknown-illumos`](https://github.com/rust-lang/rust/pull/112936/)
- [`hexagon-unknown-none-elf`](https://github.com/rust-lang/rust/pull/117601/)
- [`riscv32imafc-esp-espidf`](https://github.com/rust-lang/rust/pull/119738/)
- [`riscv32im-risc0-zkvm-elf`](https://github.com/rust-lang/rust/pull/117958/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Implement `From<&[T; N]>` for `Cow<[T]>`.](https://github.com/rust-lang/rust/pull/113489/)
- [Remove special-case handling of `vec.split_off(0)`.](https://github.com/rust-lang/rust/pull/119917/)
Stabilized APIs
---------------
- [`array::each_ref`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_ref)
- [`array::each_mut`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_mut)
- [`core::net`](https://doc.rust-lang.org/stable/core/net/index.html)
- [`f32::round_ties_even`](https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even)
- [`f64::round_ties_even`](https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even)
- [`mem::offset_of!`](https://doc.rust-lang.org/stable/std/mem/macro.offset_of.html)
- [`slice::first_chunk`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first_chunk)
- [`slice::first_chunk_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.first_chunk_mut)
- [`slice::split_first_chunk`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first_chunk)
- [`slice::split_first_chunk_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_first_chunk_mut)
- [`slice::last_chunk`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last_chunk)
- [`slice::last_chunk_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.last_chunk_mut)
- [`slice::split_last_chunk`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last_chunk)
- [`slice::split_last_chunk_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_last_chunk_mut)
- [`slice::chunk_by`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.chunk_by)
- [`slice::chunk_by_mut`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.chunk_by_mut)
- [`Bound::map`](https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.map)
- [`File::create_new`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.create_new)
- [`Mutex::clear_poison`](https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.clear_poison)
- [`RwLock::clear_poison`](https://doc.rust-lang.org/stable/std/sync/struct.RwLock.html#method.clear_poison)
Cargo
-----
- [Extend the build directive syntax with `cargo::`.](https://github.com/rust-lang/cargo/pull/12201/)
- [Stabilize metadata `id` format as `PackageIDSpec`.](https://github.com/rust-lang/cargo/pull/12914/)
- [Pull out `cargo-util-schemas` as a crate.](https://github.com/rust-lang/cargo/pull/13178/)
- [Strip all debuginfo when debuginfo is not requested.](https://github.com/rust-lang/cargo/pull/13257/)
- [Inherit jobserver from env for all kinds of runners.](https://github.com/rust-lang/cargo/pull/12776/)
- [Deprecate rustc plugin support in cargo.](https://github.com/rust-lang/cargo/pull/13248/)
Rustdoc
-----
- [Allows links in markdown headings.](https://github.com/rust-lang/rust/pull/117662/)
- [Search for tuples and unit by type with `()`.](https://github.com/rust-lang/rust/pull/118194/)
- [Clean up the source sidebar's hide button.](https://github.com/rust-lang/rust/pull/119066/)
- [Prevent JS injection from `localStorage`.](https://github.com/rust-lang/rust/pull/120250/)
Misc
----
- [Recommend version-sorting for all sorting in style guide.](https://github.com/rust-lang/rust/pull/115046/)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Add more weirdness to `weird-exprs.rs`.](https://github.com/rust-lang/rust/pull/119028/)
Version 1.76.0 (2024-02-08)
==========================
Language
--------
- [Document Rust ABI compatibility between various types](https://github.com/rust-lang/rust/pull/115476/)
- [Also: guarantee that char and u32 are ABI-compatible](https://github.com/rust-lang/rust/pull/118032/)
- [Add lint `ambiguous_wide_pointer_comparisons` that supersedes `clippy::vtable_address_comparisons`](https://github.com/rust-lang/rust/pull/117758)
Compiler
--------
- [Lint pinned `#[must_use]` pointers (in particular, `Box` where `T` is `#[must_use]`) in `unused_must_use`.](https://github.com/rust-lang/rust/pull/118054/)
- [Soundness fix: fix computing the offset of an unsized field in a packed struct](https://github.com/rust-lang/rust/pull/118540/)
- [Soundness fix: fix dynamic size/align computation logic for packed types with dyn Trait tail](https://github.com/rust-lang/rust/pull/118538/)
- [Add `$message_type` field to distinguish json diagnostic outputs](https://github.com/rust-lang/rust/pull/115691/)
- [Enable Rust to use the EHCont security feature of Windows](https://github.com/rust-lang/rust/pull/118013/)
- [Add tier 3 {x86_64,i686}-win7-windows-msvc targets](https://github.com/rust-lang/rust/pull/118150/)
- [Add tier 3 aarch64-apple-watchos target](https://github.com/rust-lang/rust/pull/119074/)
- [Add tier 3 arm64e-apple-ios & arm64e-apple-darwin targets](https://github.com/rust-lang/rust/pull/115526/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Add a column number to `dbg!()`](https://github.com/rust-lang/rust/pull/114962/)
- [Add `std::hash::{DefaultHasher, RandomState}` exports](https://github.com/rust-lang/rust/pull/115694/)
- [Fix rounding issue with exponents in fmt](https://github.com/rust-lang/rust/pull/116301/)
- [Add T: ?Sized to `RwLockReadGuard` and `RwLockWriteGuard`'s Debug impls.](https://github.com/rust-lang/rust/pull/117138/)
- [Windows: Allow `File::create` to work on hidden files](https://github.com/rust-lang/rust/pull/116438/)
Stabilized APIs
---------------
- [`Arc::unwrap_or_clone`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.unwrap_or_clone)
- [`Rc::unwrap_or_clone`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.unwrap_or_clone)
- [`Result::inspect`](https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.inspect)
- [`Result::inspect_err`](https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.inspect_err)
- [`Option::inspect`](https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.inspect)
- [`type_name_of_val`](https://doc.rust-lang.org/stable/std/any/fn.type_name_of_val.html)
- [`std::hash::{DefaultHasher, RandomState}`](https://doc.rust-lang.org/stable/std/hash/index.html#structs)
These were previously available only through `std::collections::hash_map`.
- [`ptr::{from_ref, from_mut}`](https://doc.rust-lang.org/stable/std/ptr/fn.from_ref.html)
- [`ptr::addr_eq`](https://doc.rust-lang.org/stable/std/ptr/fn.addr_eq.html)
Cargo
-----
See [Cargo release notes](https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-176-2024-02-08).
Rustdoc
-------
- [Don't merge cfg and doc(cfg) attributes for re-exports](https://github.com/rust-lang/rust/pull/113091/)
- [rustdoc: allow resizing the sidebar / hiding the top bar](https://github.com/rust-lang/rust/pull/115660/)
- [rustdoc-search: add support for traits and associated types](https://github.com/rust-lang/rust/pull/116085/)
- [rustdoc: Add highlighting for comments in items declaration](https://github.com/rust-lang/rust/pull/117869/)
Compatibility Notes
-------------------
- [Add allow-by-default lint for unit bindings](https://github.com/rust-lang/rust/pull/112380/)
This is expected to be upgraded to a warning by default in a future Rust
release. Some macros emit bindings with type `()` with user-provided spans,
which means that this lint will warn for user code.
- [Remove x86_64-sun-solaris target.](https://github.com/rust-lang/rust/pull/118091/)
- [Remove asmjs-unknown-emscripten target](https://github.com/rust-lang/rust/pull/117338/)
- [Report errors in jobserver inherited through environment variables](https://github.com/rust-lang/rust/pull/113730/)
This [may warn](https://github.com/rust-lang/rust/issues/120515) on benign problems too.
- [Update the minimum external LLVM to 16.](https://github.com/rust-lang/rust/pull/117947/)
- [Improve `print_tts`](https://github.com/rust-lang/rust/pull/114571/)
This change can break some naive manual parsing of token trees in proc macro
code which expect a particular structure after `.to_string()`, rather than just arbitrary Rust code.
- [Make `IMPLIED_BOUNDS_ENTAILMENT` into a hard error from a lint](https://github.com/rust-lang/rust/pull/117984/)
- [Vec's allocation behavior was changed when collecting some iterators](https://github.com/rust-lang/rust/pull/110353)
Allocation behavior is currently not specified, nevertheless changes can be surprising.
See [`impl FromIterator for Vec`](https://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#impl-FromIterator%3CT%3E-for-Vec%3CT%3E)
for more details.
- [Properly reject `default` on free const items](https://github.com/rust-lang/rust/pull/117818/)
Version 1.75.0 (2023-12-28)
==========================
Language
--------
- [Stabilize `async fn` and return-position `impl Trait` in traits.](https://github.com/rust-lang/rust/pull/115822/)
- [Allow function pointer signatures containing `&mut T` in `const` contexts.](https://github.com/rust-lang/rust/pull/116015/)
- [Match `usize`/`isize` exhaustively with half-open ranges.](https://github.com/rust-lang/rust/pull/116692/)
- [Guarantee that `char` has the same size and alignment as `u32`.](https://github.com/rust-lang/rust/pull/116894/)
- [Document that the null pointer has the 0 address.](https://github.com/rust-lang/rust/pull/116988/)
- [Allow partially moved values in `match`.](https://github.com/rust-lang/rust/pull/103208/)
- [Add notes about non-compliant FP behavior on 32bit x86 targets.](https://github.com/rust-lang/rust/pull/113053/)
- [Stabilize ratified RISC-V target features.](https://github.com/rust-lang/rust/pull/116485/)
Compiler
--------
- [Rework negative coherence to properly consider impls that only partly overlap.](https://github.com/rust-lang/rust/pull/112875/)
- [Bump `COINDUCTIVE_OVERLAP_IN_COHERENCE` to deny, and warn in dependencies.](https://github.com/rust-lang/rust/pull/116493/)
- [Consider alias bounds when computing liveness in NLL.](https://github.com/rust-lang/rust/pull/116733/)
- [Add the V (vector) extension to the `riscv64-linux-android` target spec.](https://github.com/rust-lang/rust/pull/116618/)
- [Automatically enable cross-crate inlining for small functions](https://github.com/rust-lang/rust/pull/116505)
- Add several new tier 3 targets:
- [`csky-unknown-linux-gnuabiv2hf`](https://github.com/rust-lang/rust/pull/117049/)
- [`i586-unknown-netbsd`](https://github.com/rust-lang/rust/pull/117170/)
- [`mipsel-unknown-netbsd`](https://github.com/rust-lang/rust/pull/117356/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Override `Waker::clone_from` to avoid cloning `Waker`s unnecessarily.](https://github.com/rust-lang/rust/pull/96979/)
- [Implement `BufRead` for `VecDeque`.](https://github.com/rust-lang/rust/pull/110604/)
- [Implement `FusedIterator` for `DecodeUtf16` when the inner iterator does.](https://github.com/rust-lang/rust/pull/110729/)
- [Implement `Not, Bit{And,Or}{,Assign}` for IP addresses.](https://github.com/rust-lang/rust/pull/113747/)
- [Implement `Default` for `ExitCode`.](https://github.com/rust-lang/rust/pull/114589/)
- [Guarantee representation of None in NPO](https://github.com/rust-lang/rust/pull/115333/)
- [Document when atomic loads are guaranteed read-only.](https://github.com/rust-lang/rust/pull/115577/)
- [Broaden the consequences of recursive TLS initialization.](https://github.com/rust-lang/rust/pull/116172/)
- [Windows: Support sub-millisecond sleep.](https://github.com/rust-lang/rust/pull/116461/)
- [Fix generic bound of `str::SplitInclusive`'s `DoubleEndedIterator` impl](https://github.com/rust-lang/rust/pull/100806/)
- [Fix exit status / wait status on non-Unix `cfg(unix)` platforms.](https://github.com/rust-lang/rust/pull/115108/)
Stabilized APIs
---------------
- [`Atomic*::from_ptr`](https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.from_ptr)
- [`FileTimes`](https://doc.rust-lang.org/stable/std/fs/struct.FileTimes.html)
- [`FileTimesExt`](https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTimesExt.html)
- [`File::set_modified`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.set_modified)
- [`File::set_times`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.set_times)
- [`IpAddr::to_canonical`](https://doc.rust-lang.org/stable/core/net/enum.IpAddr.html#method.to_canonical)
- [`Ipv6Addr::to_canonical`](https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.to_canonical)
- [`Option::as_slice`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_slice)
- [`Option::as_mut_slice`](https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_mut_slice)
- [`pointer::byte_add`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_add)
- [`pointer::byte_offset`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_offset)
- [`pointer::byte_offset_from`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_offset_from)
- [`pointer::byte_sub`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_sub)
- [`pointer::wrapping_byte_add`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_add)
- [`pointer::wrapping_byte_offset`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_offset)
- [`pointer::wrapping_byte_sub`](https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_sub)
These APIs are now stable in const contexts:
- [`Ipv6Addr::to_ipv4_mapped`](https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.to_ipv4_mapped)
- [`MaybeUninit::assume_init_read`](https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.assume_init_read)
- [`MaybeUninit::zeroed`](https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.zeroed)
- [`mem::discriminant`](https://doc.rust-lang.org/stable/core/mem/fn.discriminant.html)
- [`mem::zeroed`](https://doc.rust-lang.org/stable/core/mem/fn.zeroed.html)
Cargo
-----
- [Add new packages to `[workspace.members]` automatically.](https://github.com/rust-lang/cargo/pull/12779/)
- [Allow version-less `Cargo.toml` manifests.](https://github.com/rust-lang/cargo/pull/12786/)
- [Make browser links out of HTML file paths.](https://github.com/rust-lang/cargo/pull/12889)
Rustdoc
-------
- [Accept less invalid Rust in rustdoc.](https://github.com/rust-lang/rust/pull/117450/)
- [Document lack of object safety on affected traits.](https://github.com/rust-lang/rust/pull/113241/)
- [Hide `#[repr(transparent)]` if it isn't part of the public ABI.](https://github.com/rust-lang/rust/pull/115439/)
- [Show enum discriminant if it is a C-like variant.](https://github.com/rust-lang/rust/pull/116142/)
Compatibility Notes
-------------------
- [FreeBSD targets now require at least version 12.](https://github.com/rust-lang/rust/pull/114521/)
- [Formally demote tier 2 MIPS targets to tier 3.](https://github.com/rust-lang/rust/pull/115238/)
- [Make misalignment a hard error in `const` contexts.](https://github.com/rust-lang/rust/pull/115524/)
- [Fix detecting references to packed unsized fields.](https://github.com/rust-lang/rust/pull/115583/)
- [Remove support for compiler plugins.](https://github.com/rust-lang/rust/pull/116412/)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Optimize `librustc_driver.so` with BOLT.](https://github.com/rust-lang/rust/pull/116352/)
- [Enable parallel rustc front end in dev and nightly builds.](https://github.com/rust-lang/rust/pull/117435/)
- [Distribute `rustc-codegen-cranelift` as rustup component on the nightly channel.](https://github.com/rust-lang/rust/pull/81746/)
Version 1.74.1 (2023-12-07)
===========================
- [Resolved spurious STATUS_ACCESS_VIOLATIONs in LLVM](https://github.com/rust-lang/rust/pull/118464)
- [Clarify guarantees for std::mem::discriminant](https://github.com/rust-lang/rust/pull/118006)
- [Fix some subtyping-related regressions](https://github.com/rust-lang/rust/pull/116415)
Version 1.74.0 (2023-11-16)
==========================
Language
--------
- [Codify that `std::mem::Discriminant` does not depend on any lifetimes in T](https://github.com/rust-lang/rust/pull/104299/)
- [Replace `private_in_public` lint with `private_interfaces` and `private_bounds` per RFC 2145.](https://github.com/rust-lang/rust/pull/113126/)
Read more in [RFC 2145](https://rust-lang.github.io/rfcs/2145-type-privacy.html).
- [Allow explicit `#[repr(Rust)]`](https://github.com/rust-lang/rust/pull/114201/)
- [closure field capturing: don't depend on alignment of packed fields](https://github.com/rust-lang/rust/pull/115315/)
- [Enable MIR-based drop-tracking for `async` blocks](https://github.com/rust-lang/rust/pull/107421/)
- [Stabilize `impl_trait_projections`](https://github.com/rust-lang/rust/pull/115659)
Compiler
--------
- [stabilize combining +bundle and +whole-archive link modifiers](https://github.com/rust-lang/rust/pull/113301/)
- [Stabilize `PATH` option for `--print KIND=PATH`](https://github.com/rust-lang/rust/pull/114183/)
- [Enable ASAN/LSAN/TSAN for `*-apple-ios-macabi`](https://github.com/rust-lang/rust/pull/115644/)
- [Promote loongarch64-unknown-none* to Tier 2](https://github.com/rust-lang/rust/pull/115368/)
- [Add `i686-pc-windows-gnullvm` as a tier 3 target](https://github.com/rust-lang/rust/pull/115687/)
Libraries
---------
- [Implement `From` for ChildStdin/out/err](https://github.com/rust-lang/rust/pull/98704/)
- [Implement `From<{&,&mut} [T; N]>` for `Vec` where `T: Clone`](https://github.com/rust-lang/rust/pull/111278/)
- [impl Step for IP addresses](https://github.com/rust-lang/rust/pull/113748/)
- [Implement `From<[T; N]>` for `Rc<[T]>` and `Arc<[T]>`](https://github.com/rust-lang/rust/pull/114041/)
- [`impl TryFrom for u16`](https://github.com/rust-lang/rust/pull/114065/)
- [Stabilize `io_error_other` feature](https://github.com/rust-lang/rust/pull/115453/)
- [Stabilize the `Saturating` type](https://github.com/rust-lang/rust/pull/115477/)
- [Stabilize const_transmute_copy](https://github.com/rust-lang/rust/pull/115520/)
Stabilized APIs
---------------
- [`core::num::Saturating`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html)
- [`impl From for std::process::Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CStdout%3E-for-Stdio)
- [`impl From for std::process::Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CStderr%3E-for-Stdio)
- [`impl From for std::process::Child{Stdin, Stdout, Stderr}`](https://doc.rust-lang.org/stable/std/process/struct.ChildStderr.html#impl-From%3COwnedHandle%3E-for-ChildStderr)
- [`impl From for std::process::Child{Stdin, Stdout, Stderr}`](https://doc.rust-lang.org/stable/std/process/struct.ChildStderr.html#impl-From%3COwnedFd%3E-for-ChildStderr)
- [`std::ffi::OsString::from_encoded_bytes_unchecked`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.from_encoded_bytes_unchecked)
- [`std::ffi::OsString::into_encoded_bytes`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.into_encoded_bytes)
- [`std::ffi::OsStr::from_encoded_bytes_unchecked`](https://doc.rust-lang.org/stable/std/ffi/struct.OsStr.html#method.from_encoded_bytes_unchecked)
- [`std::ffi::OsStr::as_encoded_bytes`](https://doc.rust-lang.org/stable/std/ffi/struct.OsStr.html#method.as_encoded_bytes)
- [`std::io::Error::other`](https://doc.rust-lang.org/stable/std/io/struct.Error.html#method.other)
- [`impl TryFrom for u16`](https://doc.rust-lang.org/stable/std/primitive.u16.html#impl-TryFrom%3Cchar%3E-for-u16)
- [`impl From<&[T; N]> for Vec`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#impl-From%3C%26%5BT;+N%5D%3E-for-Vec%3CT,+Global%3E)
- [`impl From<&mut [T; N]> for Vec`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#impl-From%3C%26mut+%5BT;+N%5D%3E-for-Vec%3CT,+Global%3E)
- [`impl From<[T; N]> for Arc<[T]>`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#impl-From%3C%5BT;+N%5D%3E-for-Arc%3C%5BT%5D,+Global%3E)
- [`impl From<[T; N]> for Rc<[T]>`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#impl-From%3C%5BT;+N%5D%3E-for-Rc%3C%5BT%5D,+Global%3E)
These APIs are now stable in const contexts:
- [`core::mem::transmute_copy`](https://doc.rust-lang.org/beta/std/mem/fn.transmute_copy.html)
- [`str::is_ascii`](https://doc.rust-lang.org/beta/std/primitive.str.html#method.is_ascii)
- [`[u8]::is_ascii`](https://doc.rust-lang.org/beta/std/primitive.slice.html#method.is_ascii)
Cargo
-----
- [In `Cargo.toml`, stabilize `[lints]`](https://github.com/rust-lang/cargo/pull/12648/)
- [Stabilize credential-process and registry-auth](https://github.com/rust-lang/cargo/pull/12649/)
- [Stabilize `--keep-going` build flag](https://github.com/rust-lang/cargo/pull/12568/)
- [Add styling to `--help` output](https://github.com/rust-lang/cargo/pull/12578/)
- [For `cargo clean`, add `--dry-run` flag and summary line at the end](https://github.com/rust-lang/cargo/pull/12638)
- [For `cargo update`, make `--package` more convenient by being positional](https://github.com/rust-lang/cargo/pull/12545/)
- [For `cargo update`, clarify meaning of --aggressive as --recursive](https://github.com/rust-lang/cargo/pull/12544/)
- [Add '-n' as an alias for `--dry-run`](https://github.com/rust-lang/cargo/pull/12660/)
- [Allow version-prefixes in pkgid's (e.g. `--package` flags) to resolve ambiguities](https://github.com/rust-lang/cargo/pull/12614/)
- [In `.cargo/config.toml`, merge lists in precedence order](https://github.com/rust-lang/cargo/pull/12515/)
- [Add support for `target.'cfg(..)'.linker`](https://github.com/rust-lang/cargo/pull/12535/)
Rustdoc
-------
- [Add warning block support in rustdoc](https://github.com/rust-lang/rust/pull/106561/)
- [rustdoc-search: add support for type parameters](https://github.com/rust-lang/rust/pull/112725/)
- [rustdoc: show inner enum and struct in type definition for concrete type](https://github.com/rust-lang/rust/pull/114855/)
Compatibility Notes
-------------------
- [Raise minimum supported Apple OS versions](https://github.com/rust-lang/rust/pull/104385/)
- [make Cell::swap panic if the Cells partially overlap](https://github.com/rust-lang/rust/pull/114795/)
- [Reject invalid crate names in `--extern`](https://github.com/rust-lang/rust/pull/116001/)
- [Don't resolve generic impls that may be shadowed by dyn built-in impls](https://github.com/rust-lang/rust/pull/114941/)
- [The new `impl From<{&,&mut} [T; N]> for Vec` is known to cause some inference failures with overly-generic code.](https://github.com/rust-lang/rust/issues/117054) In those examples using the `tui` crate, the combination of `AsRef<_>` and `Into` leaves the middle type ambiguous, and the new `impl` adds another possibility, so it now requires an explicit type annotation.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
None this cycle.
Version 1.73.0 (2023-10-05)
==========================
Language
--------
- [Uplift `clippy::fn_null_check` lint as `useless_ptr_null_checks`.](https://github.com/rust-lang/rust/pull/111717/)
- [Make `noop_method_call` warn by default.](https://github.com/rust-lang/rust/pull/111916/)
- [Support interpolated block for `try` and `async` in macros.](https://github.com/rust-lang/rust/pull/112953/)
- [Make `unconditional_recursion` lint detect recursive drops.](https://github.com/rust-lang/rust/pull/113902/)
- [Future compatibility warning for some impls being incorrectly considered not overlapping.](https://github.com/rust-lang/rust/pull/114023/)
- [The `invalid_reference_casting` lint is now **deny-by-default** (instead of allow-by-default)](https://github.com/rust-lang/rust/pull/112431)
Compiler
--------
- [Write version information in a `.comment` section like GCC/Clang.](https://github.com/rust-lang/rust/pull/97550/)
- [Add documentation on v0 symbol mangling.](https://github.com/rust-lang/rust/pull/97571/)
- [Stabilize `extern "thiscall"` and `"thiscall-unwind"` ABIs.](https://github.com/rust-lang/rust/pull/114562/)
- [Only check outlives goals on impl compared to trait.](https://github.com/rust-lang/rust/pull/109356/)
- [Infer type in irrefutable slice patterns with fixed length as array.](https://github.com/rust-lang/rust/pull/113199/)
- [Discard default auto trait impls if explicit ones exist.](https://github.com/rust-lang/rust/pull/113312/)
- Add several new tier 3 targets:
- [`aarch64-unknown-teeos`](https://github.com/rust-lang/rust/pull/113480/)
- [`csky-unknown-linux-gnuabiv2`](https://github.com/rust-lang/rust/pull/113658/)
- [`riscv64-linux-android`](https://github.com/rust-lang/rust/pull/112858/)
- [`riscv64gc-unknown-hermit`](https://github.com/rust-lang/rust/pull/114004/)
- [`x86_64-unikraft-linux-musl`](https://github.com/rust-lang/rust/pull/113411/)
- [`x86_64-unknown-linux-ohos`](https://github.com/rust-lang/rust/pull/113061/)
- [Add `wasm32-wasi-preview1-threads` as a tier 2 target.](https://github.com/rust-lang/rust/pull/112922/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Add `Read`, `Write` and `Seek` impls for `Arc`.](https://github.com/rust-lang/rust/pull/94748/)
- [Merge functionality of `io::Sink` into `io::Empty`.](https://github.com/rust-lang/rust/pull/98154/)
- [Implement `RefUnwindSafe` for `Backtrace`](https://github.com/rust-lang/rust/pull/100455/)
- [Make `ExitStatus` implement `Default`](https://github.com/rust-lang/rust/pull/106425/)
- [`impl SliceIndex for (Bound, Bound)`](https://github.com/rust-lang/rust/pull/111081/)
- [Change default panic handler message format.](https://github.com/rust-lang/rust/pull/112849/)
- [Cleaner `assert_eq!` & `assert_ne!` panic messages.](https://github.com/rust-lang/rust/pull/111071/)
- [Correct the (deprecated) Android `stat` struct definitions.](https://github.com/rust-lang/rust/pull/113130/)
Stabilized APIs
---------------
- [Unsigned `{integer}::div_ceil`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.div_ceil)
- [Unsigned `{integer}::next_multiple_of`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.next_multiple_of)
- [Unsigned `{integer}::checked_next_multiple_of`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.checked_next_multiple_of)
- [`std::ffi::FromBytesUntilNulError`](https://doc.rust-lang.org/stable/std/ffi/struct.FromBytesUntilNulError.html)
- [`std::os::unix::fs::chown`](https://doc.rust-lang.org/stable/std/os/unix/fs/fn.chown.html)
- [`std::os::unix::fs::fchown`](https://doc.rust-lang.org/stable/std/os/unix/fs/fn.fchown.html)
- [`std::os::unix::fs::lchown`](https://doc.rust-lang.org/stable/std/os/unix/fs/fn.lchown.html)
- [`LocalKey::>::get`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.get)
- [`LocalKey::>::set`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.set)
- [`LocalKey::>::take`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.take)
- [`LocalKey::>::replace`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.replace)
- [`LocalKey::>::with_borrow`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.with_borrow)
- [`LocalKey::>::with_borrow_mut`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.with_borrow_mut)
- [`LocalKey::>::set`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.set-1)
- [`LocalKey::>::take`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.take-1)
- [`LocalKey::>::replace`](https://doc.rust-lang.org/stable/std/thread/struct.LocalKey.html#method.replace-1)
These APIs are now stable in const contexts:
- [`rc::Weak::new`](https://doc.rust-lang.org/stable/alloc/rc/struct.Weak.html#method.new)
- [`sync::Weak::new`](https://doc.rust-lang.org/stable/alloc/sync/struct.Weak.html#method.new)
- [`NonNull::as_ref`](https://doc.rust-lang.org/stable/core/ptr/struct.NonNull.html#method.as_ref)
Cargo
-----
- [Bail out an error when using `cargo::` in custom build script.](https://github.com/rust-lang/cargo/pull/12332/)
Misc
----
Compatibility Notes
-------------------
- [Update the minimum external LLVM to 15.](https://github.com/rust-lang/rust/pull/114148/)
- [Check for non-defining uses of return position `impl Trait`.](https://github.com/rust-lang/rust/pull/112842/)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Remove LLVM pointee types, supporting only opaque pointers.](https://github.com/rust-lang/rust/pull/105545/)
- [Port PGO/LTO/BOLT optimized build pipeline to Rust.](https://github.com/rust-lang/rust/pull/112235/)
- [Replace in-tree `rustc_apfloat` with the new version of the crate.](https://github.com/rust-lang/rust/pull/113843/)
- [Update to LLVM 17.](https://github.com/rust-lang/rust/pull/114048/)
- [Add `internal_features` lint for internal unstable features.](https://github.com/rust-lang/rust/pull/108955/)
- [Mention style for new syntax in tracking issue template.](https://github.com/rust-lang/rust/pull/113586/)
Version 1.72.1 (2023-09-19)
===========================
- [Adjust codegen change to improve LLVM codegen](https://github.com/rust-lang/rust/pull/115236)
- [rustdoc: Fix self ty params in objects with lifetimes](https://github.com/rust-lang/rust/pull/115276)
- [Fix regression in compile times](https://github.com/rust-lang/rust/pull/114948)
- Resolve some ICE regressions in the compiler:
- [#115215](https://github.com/rust-lang/rust/pull/115215)
- [#115559](https://github.com/rust-lang/rust/pull/115559)
Version 1.72.0 (2023-08-24)
==========================
Language
--------
- [Replace const eval limit by a lint and add an exponential backoff warning](https://github.com/rust-lang/rust/pull/103877/)
- [expand: Change how `#![cfg(FALSE)]` behaves on crate root](https://github.com/rust-lang/rust/pull/110141/)
- [Stabilize inline asm for LoongArch64](https://github.com/rust-lang/rust/pull/111235/)
- [Uplift `clippy::undropped_manually_drops` lint](https://github.com/rust-lang/rust/pull/111530/)
- [Uplift `clippy::invalid_utf8_in_unchecked` lint](https://github.com/rust-lang/rust/pull/111543/) as `invalid_from_utf8_unchecked` and `invalid_from_utf8`
- [Uplift `clippy::cast_ref_to_mut` lint](https://github.com/rust-lang/rust/pull/111567/) as `invalid_reference_casting`
- [Uplift `clippy::cmp_nan` lint](https://github.com/rust-lang/rust/pull/111818/) as `invalid_nan_comparisons`
- [resolve: Remove artificial import ambiguity errors](https://github.com/rust-lang/rust/pull/112086/)
- [Don't require associated types with Self: Sized bounds in `dyn Trait` objects](https://github.com/rust-lang/rust/pull/112319/)
Compiler
--------
- [Remember names of `cfg`-ed out items to mention them in diagnostics](https://github.com/rust-lang/rust/pull/109005/)
- [Support for native WASM exceptions](https://github.com/rust-lang/rust/pull/111322/)
- [Add support for NetBSD/aarch64-be (big-endian arm64).](https://github.com/rust-lang/rust/pull/111326/)
- [Write to stdout if `-` is given as output file](https://github.com/rust-lang/rust/pull/111626/)
- [Force all native libraries to be statically linked when linking a static binary](https://github.com/rust-lang/rust/pull/111698/)
- [Add Tier 3 support for `loongarch64-unknown-none*`](https://github.com/rust-lang/rust/pull/112310/)
- [Prevent `.eh_frame` from being emitted for `-C panic=abort`](https://github.com/rust-lang/rust/pull/112403/)
- [Support 128-bit enum variant in debuginfo codegen](https://github.com/rust-lang/rust/pull/112474/)
- [compiler: update solaris/illumos to enable tsan support.](https://github.com/rust-lang/rust/pull/112039/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Document memory orderings of `thread::{park, unpark}`](https://github.com/rust-lang/rust/pull/99587/)
- [io: soften ‘at most one write attempt’ requirement in io::Write::write](https://github.com/rust-lang/rust/pull/107200/)
- [Specify behavior of HashSet::insert](https://github.com/rust-lang/rust/pull/107619/)
- [Relax implicit `T: Sized` bounds on `BufReader`, `BufWriter` and `LineWriter`](https://github.com/rust-lang/rust/pull/111074/)
- [Update runtime guarantee for `select_nth_unstable`](https://github.com/rust-lang/rust/pull/111974/)
- [Return `Ok` on kill if process has already exited](https://github.com/rust-lang/rust/pull/112594/)
- [Implement PartialOrd for `Vec`s over different allocators](https://github.com/rust-lang/rust/pull/112632/)
- [Use 128 bits for TypeId hash](https://github.com/rust-lang/rust/pull/109953/)
- [Don't drain-on-drop in DrainFilter impls of various collections.](https://github.com/rust-lang/rust/pull/104455/)
- [Make `{Arc,Rc,Weak}::ptr_eq` ignore pointer metadata](https://github.com/rust-lang/rust/pull/106450/)
Rustdoc
-------
- [Allow whitespace as path separator like double colon](https://github.com/rust-lang/rust/pull/108537/)
- [Add search result item types after their name](https://github.com/rust-lang/rust/pull/110688/)
- [Search for slices and arrays by type with `[]`](https://github.com/rust-lang/rust/pull/111958/)
- [Clean up type unification and "unboxing"](https://github.com/rust-lang/rust/pull/112233/)
Stabilized APIs
---------------
- [`impl Sync for mpsc::Sender`](https://doc.rust-lang.org/stable/std/sync/mpsc/struct.Sender.html#impl-Sync-for-Sender%3CT%3E)
- [`impl TryFrom<&OsStr> for &str`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-TryFrom%3C%26'a+OsStr%3E-for-%26'a+str)
- [`String::leak`](https://doc.rust-lang.org/stable/alloc/string/struct.String.html#method.leak)
These APIs are now stable in const contexts:
- [`CStr::from_bytes_with_nul`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.from_bytes_with_nul)
- [`CStr::to_bytes`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.to_bytes)
- [`CStr::to_bytes_with_nul`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.to_bytes_with_nul)
- [`CStr::to_str`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.to_str)
Cargo
-----
- Enable `-Zdoctest-in-workspace` by default. When running each documentation
test, the working directory is set to the root directory of the package the
test belongs to.
[docs](https://doc.rust-lang.org/nightly/cargo/commands/cargo-test.html#working-directory-of-tests)
[#12221](https://github.com/rust-lang/cargo/pull/12221)
[#12288](https://github.com/rust-lang/cargo/pull/12288)
- Add support of the "default" keyword to reset previously set `build.jobs`
parallelism back to the default.
[#12222](https://github.com/rust-lang/cargo/pull/12222)
Compatibility Notes
-------------------
- [Alter `Display` for `Ipv6Addr` for IPv4-compatible addresses](https://github.com/rust-lang/rust/pull/112606/)
- Cargo changed feature name validation check to a hard error. The warning was
added in Rust 1.49. These extended characters aren't allowed on crates.io, so
this should only impact users of other registries, or people who don't publish
to a registry.
[#12291](https://github.com/rust-lang/cargo/pull/12291)
- [Demoted `mips*-unknown-linux-gnu*` targets from host tier 2 to target tier 3 support.](https://github.com/rust-lang/rust/pull/113274)
Version 1.71.1 (2023-08-03)
===========================
- [Fix CVE-2023-38497: Cargo did not respect the umask when extracting dependencies](https://github.com/rust-lang/cargo/security/advisories/GHSA-j3xp-wfr4-hx87)
- [Fix bash completion for users of Rustup](https://github.com/rust-lang/rust/pull/113579)
- [Do not show `suspicious_double_ref_op` lint when calling `borrow()`](https://github.com/rust-lang/rust/pull/112517)
- [Fix ICE: substitute types before checking inlining compatibility](https://github.com/rust-lang/rust/pull/113802)
- [Fix ICE: don't use `can_eq` in `derive(..)` suggestion for missing method](https://github.com/rust-lang/rust/pull/111516)
- [Fix building Rust 1.71.0 from the source tarball](https://github.com/rust-lang/rust/issues/113678)
Version 1.71.0 (2023-07-13)
==========================
Language
--------
- [Stabilize `raw-dylib`, `link_ordinal`, `import_name_type` and `-Cdlltool`.](https://github.com/rust-lang/rust/pull/109677/)
- [Uplift `clippy::{drop,forget}_{ref,copy}` lints.](https://github.com/rust-lang/rust/pull/109732/)
- [Type inference is more conservative around constrained vars.](https://github.com/rust-lang/rust/pull/110100/)
- [Use fulfillment to check `Drop` impl compatibility](https://github.com/rust-lang/rust/pull/110577/)
Compiler
--------
- [Evaluate place expression in `PlaceMention`](https://github.com/rust-lang/rust/pull/104844/),
making `let _ =` patterns more consistent with respect to the borrow checker.
- [Add `--print deployment-target` flag for Apple targets.](https://github.com/rust-lang/rust/pull/105354/)
- [Stabilize `extern "C-unwind"` and friends.](https://github.com/rust-lang/rust/pull/106075/)
The existing `extern "C"` etc. may change behavior for cross-language unwinding in a future release.
- [Update the version of musl used on `*-linux-musl` targets to 1.2.3](https://github.com/rust-lang/rust/pull/107129/),
enabling [time64](https://musl.libc.org/time64.html) on 32-bit systems.
- [Stabilize `debugger_visualizer`](https://github.com/rust-lang/rust/pull/108668/)
for embedding metadata like Microsoft's Natvis.
- [Enable flatten-format-args by default.](https://github.com/rust-lang/rust/pull/109999/)
- [Make `Self` respect tuple constructor privacy.](https://github.com/rust-lang/rust/pull/111245/)
- [Improve niche placement by trying two strategies and picking the better result.](https://github.com/rust-lang/rust/pull/108106/)
- [Use `apple-m1` as the target CPU for `aarch64-apple-darwin`.](https://github.com/rust-lang/rust/pull/109899/)
- [Add Tier 3 support for the `x86_64h-apple-darwin` target.](https://github.com/rust-lang/rust/pull/108795/)
- [Promote `loongarch64-unknown-linux-gnu` to Tier 2 with host tools.](https://github.com/rust-lang/rust/pull/110936/)
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Rework handling of recursive panics.](https://github.com/rust-lang/rust/pull/110975/)
Additional panics are allowed while unwinding, as long as they are caught before escaping
a `Drop` implementation, but panicking within a panic hook is now an immediate abort.
- [Loosen `From<&[T]> for Box<[T]>` bound to `T: Clone`.](https://github.com/rust-lang/rust/pull/103406/)
- [Remove unnecessary `T: Send` bound](https://github.com/rust-lang/rust/pull/111134/)
in `Error for mpsc::SendError` and `TrySendError`.
- [Fix docs for `alloc::realloc`](https://github.com/rust-lang/rust/pull/108630/)
to match `Layout` requirements that the size must not exceed `isize::MAX`.
- [Document `const {}` syntax for `std::thread_local`.](https://github.com/rust-lang/rust/pull/110620/)
This syntax was stabilized in Rust 1.59, but not previously mentioned in release notes.
Stabilized APIs
---------------
- [`CStr::is_empty`](https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.is_empty)
- [`BuildHasher::hash_one`](https://doc.rust-lang.org/stable/std/hash/trait.BuildHasher.html#method.hash_one)
- [`NonZeroI*::is_positive`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#method.is_positive)
- [`NonZeroI*::is_negative`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#method.is_negative)
- [`NonZeroI*::checked_neg`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#method.checked_neg)
- [`NonZeroI*::overflowing_neg`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#method.overflowing_neg)
- [`NonZeroI*::saturating_neg`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#method.saturating_neg)
- [`NonZeroI*::wrapping_neg`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#method.wrapping_neg)
- [`Neg for NonZeroI*`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#impl-Neg-for-NonZeroI32)
- [`Neg for &NonZeroI*`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI32.html#impl-Neg-for-%26NonZeroI32)
- [`From<[T; N]> for (T...)`](https://doc.rust-lang.org/stable/std/primitive.array.html#impl-From%3C%5BT;+1%5D%3E-for-(T,))
(array to N-tuple for N in 1..=12)
- [`From<(T...)> for [T; N]`](https://doc.rust-lang.org/stable/std/primitive.array.html#impl-From%3C(T,)%3E-for-%5BT;+1%5D)
(N-tuple to array for N in 1..=12)
- [`windows::io::AsHandle for Box`](https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsHandle.html#impl-AsHandle-for-Box%3CT%3E)
- [`windows::io::AsHandle for Rc`](https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsHandle.html#impl-AsHandle-for-Rc%3CT%3E)
- [`windows::io::AsHandle for Arc`](https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsHandle.html#impl-AsHandle-for-Arc%3CT%3E)
- [`windows::io::AsSocket for Box`](https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsSocket.html#impl-AsSocket-for-Box%3CT%3E)
- [`windows::io::AsSocket for Rc`](https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsSocket.html#impl-AsSocket-for-Rc%3CT%3E)
- [`windows::io::AsSocket for Arc`](https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsSocket.html#impl-AsSocket-for-Arc%3CT%3E)
These APIs are now stable in const contexts:
- [`<*const T>::read`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.read)
- [`<*const T>::read_unaligned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.read_unaligned)
- [`<*mut T>::read`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.read-1)
- [`<*mut T>::read_unaligned`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.read_unaligned-1)
- [`ptr::read`](https://doc.rust-lang.org/stable/std/ptr/fn.read.html)
- [`ptr::read_unaligned`](https://doc.rust-lang.org/stable/std/ptr/fn.read_unaligned.html)
- [`<[T]>::split_at`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.split_at)
Cargo
-----
- [Allow named debuginfo options in `Cargo.toml`.](https://github.com/rust-lang/cargo/pull/11958/)
- [Add `workspace_default_members` to the output of `cargo metadata`.](https://github.com/rust-lang/cargo/pull/11978/)
- [Automatically inherit workspace fields when running `cargo new`/`cargo init`.](https://github.com/rust-lang/cargo/pull/12069/)
Rustdoc
-------
- [Add a new `rustdoc::unescaped_backticks` lint for broken inline code.](https://github.com/rust-lang/rust/pull/105848/)
- [Support strikethrough with single tildes.](https://github.com/rust-lang/rust/pull/111152/) (`~~old~~` vs. `~new~`)
Misc
----
Compatibility Notes
-------------------
- [Remove structural match from `TypeId`.](https://github.com/rust-lang/rust/pull/103291/)
Code that uses a constant `TypeId` in a pattern will potentially be broken.
Known cases have already been fixed -- in particular, users of the `log`
crate's `kv_unstable` feature should update to `log v0.4.18` or later.
- [Add a `sysroot` crate to represent the standard library crates.](https://github.com/rust-lang/rust/pull/108865/)
This does not affect stable users, but may require adjustment in tools that build their own standard library.
- [Cargo optimizes its usage under `rustup`.](https://github.com/rust-lang/cargo/pull/11917/) When
Cargo detects it will run `rustc` pointing to a rustup proxy, it'll try bypassing the proxy and
use the underlying binary directly. There are assumptions around the interaction with rustup and
`RUSTUP_TOOLCHAIN`. However, it's not expected to affect normal users.
- [When querying a package, Cargo tries only the original name, all hyphens, and all underscores to
handle misspellings.](https://github.com/rust-lang/cargo/pull/12083/) Previously, Cargo tried each
combination of hyphens and underscores, causing excessive requests to crates.io.
- Cargo now [disallows `RUSTUP_HOME`](https://github.com/rust-lang/cargo/pull/12101/) and
[`RUSTUP_TOOLCHAIN`](https://github.com/rust-lang/cargo/pull/12107/) in the `[env]` configuration
table. This is considered to be not a use case Cargo would like to support, since it will likely
cause problems or lead to confusion.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
Version 1.70.0 (2023-06-01)
==========================
Language
--------
- [Relax ordering rules for `asm!` operands](https://github.com/rust-lang/rust/pull/105798/)
- [Properly allow macro expanded `format_args` invocations to uses captures](https://github.com/rust-lang/rust/pull/106505/)
- [Lint ambiguous glob re-exports](https://github.com/rust-lang/rust/pull/107880/)
- [Perform const and unsafe checking for expressions in `let _ = expr` position.](https://github.com/rust-lang/rust/pull/102256/)
Compiler
--------
- [Extend -Cdebuginfo with new options and named aliases](https://github.com/rust-lang/rust/pull/109808/)
This provides a smaller version of debuginfo for cases that only need line number information
(`-Cdebuginfo=line-tables-only`), which may eventually become the default for `-Cdebuginfo=1`.
- [Make `unused_allocation` lint against `Box::new` too](https://github.com/rust-lang/rust/pull/104363/)
- [Detect uninhabited types early in const eval](https://github.com/rust-lang/rust/pull/109435/)
- [Switch to LLD as default linker for {arm,thumb}v4t-none-eabi](https://github.com/rust-lang/rust/pull/109721/)
- [Add tier 3 target `loongarch64-unknown-linux-gnu`](https://github.com/rust-lang/rust/pull/96971)
- [Add tier 3 target for `i586-pc-nto-qnx700` (QNX Neutrino RTOS, version 7.0)](https://github.com/rust-lang/rust/pull/109173/),
- [Insert alignment checks for pointer dereferences as debug assertions](https://github.com/rust-lang/rust/pull/98112)
This catches undefined behavior at runtime, and may cause existing code to fail.
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Document NonZeroXxx layout guarantees](https://github.com/rust-lang/rust/pull/94786/)
- [Windows: make `Command` prefer non-verbatim paths](https://github.com/rust-lang/rust/pull/96391/)
- [Implement Default for some alloc/core iterators](https://github.com/rust-lang/rust/pull/99929/)
- [Fix handling of trailing bare CR in str::lines](https://github.com/rust-lang/rust/pull/100311/)
- [allow negative numeric literals in `concat!`](https://github.com/rust-lang/rust/pull/106844/)
- [Add documentation about the memory layout of `Cell`](https://github.com/rust-lang/rust/pull/106921/)
- [Use `partial_cmp` to implement tuple `lt`/`le`/`ge`/`gt`](https://github.com/rust-lang/rust/pull/108157/)
- [Stabilize `atomic_as_ptr`](https://github.com/rust-lang/rust/pull/108419/)
- [Stabilize `nonnull_slice_from_raw_parts`](https://github.com/rust-lang/rust/pull/97506/)
- [Partial stabilization of `once_cell`](https://github.com/rust-lang/rust/pull/105587/)
- [Stabilize `nonzero_min_max`](https://github.com/rust-lang/rust/pull/106633/)
- [Flatten/inline format_args!() and (string and int) literal arguments into format_args!()](https://github.com/rust-lang/rust/pull/106824/)
- [Stabilize movbe target feature](https://github.com/rust-lang/rust/pull/107711/)
- [don't splice from files into pipes in io::copy](https://github.com/rust-lang/rust/pull/108283/)
- [Add a builtin unstable `FnPtr` trait that is implemented for all function pointers](https://github.com/rust-lang/rust/pull/108080/)
This extends `Debug`, `Pointer`, `Hash`, `PartialEq`, `Eq`, `PartialOrd`, and `Ord`
implementations for function pointers with all ABIs.
Stabilized APIs
---------------
- [`NonZero*::MIN/MAX`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroI8.html#associatedconstant.MIN)
- [`BinaryHeap::retain`](https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.retain)
- [`Default for std::collections::binary_heap::IntoIter`](https://doc.rust-lang.org/stable/std/collections/binary_heap/struct.IntoIter.html)
- [`Default for std::collections::btree_map::{IntoIter, Iter, IterMut}`](https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoIter.html)
- [`Default for std::collections::btree_map::{IntoKeys, Keys}`](https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html)
- [`Default for std::collections::btree_map::{IntoValues, Values}`](https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoValues.html)
- [`Default for std::collections::btree_map::Range`](https://doc.rust-lang.org/stable/std/collections/btree_map/struct.Range.html)
- [`Default for std::collections::btree_set::{IntoIter, Iter}`](https://doc.rust-lang.org/stable/std/collections/btree_set/struct.IntoIter.html)
- [`Default for std::collections::btree_set::Range`](https://doc.rust-lang.org/stable/std/collections/btree_set/struct.Range.html)
- [`Default for std::collections::linked_list::{IntoIter, Iter, IterMut}`](https://doc.rust-lang.org/stable/alloc/collections/linked_list/struct.IntoIter.html)
- [`Default for std::vec::IntoIter`](https://doc.rust-lang.org/stable/alloc/vec/struct.IntoIter.html#impl-Default-for-IntoIter%3CT,+A%3E)
- [`Default for std::iter::Chain`](https://doc.rust-lang.org/stable/std/iter/struct.Chain.html)
- [`Default for std::iter::Cloned`](https://doc.rust-lang.org/stable/std/iter/struct.Cloned.html)
- [`Default for std::iter::Copied`](https://doc.rust-lang.org/stable/std/iter/struct.Copied.html)
- [`Default for std::iter::Enumerate`](https://doc.rust-lang.org/stable/std/iter/struct.Enumerate.html)
- [`Default for std::iter::Flatten`](https://doc.rust-lang.org/stable/std/iter/struct.Flatten.html)
- [`Default for std::iter::Fuse`](https://doc.rust-lang.org/stable/std/iter/struct.Fuse.html)
- [`Default for std::iter::Rev`](https://doc.rust-lang.org/stable/std/iter/struct.Rev.html)
- [`Default for std::slice::Iter`](https://doc.rust-lang.org/stable/std/slice/struct.Iter.html)
- [`Default for std::slice::IterMut`](https://doc.rust-lang.org/stable/std/slice/struct.IterMut.html)
- [`Rc::into_inner`](https://doc.rust-lang.org/stable/alloc/rc/struct.Rc.html#method.into_inner)
- [`Arc::into_inner`](https://doc.rust-lang.org/stable/alloc/sync/struct.Arc.html#method.into_inner)
- [`std::cell::OnceCell`](https://doc.rust-lang.org/stable/std/cell/struct.OnceCell.html)
- [`Option::is_some_and`](https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.is_some_and)
- [`NonNull::slice_from_raw_parts`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.slice_from_raw_parts)
- [`Result::is_ok_and`](https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_ok_and)
- [`Result::is_err_and`](https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_err_and)
- [`std::sync::atomic::Atomic*::as_ptr`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicU8.html#method.as_ptr)
- [`std::io::IsTerminal`](https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html)
- [`std::os::linux::net::SocketAddrExt`](https://doc.rust-lang.org/stable/std/os/linux/net/trait.SocketAddrExt.html)
- [`std::os::unix::net::UnixDatagram::bind_addr`](https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.bind_addr)
- [`std::os::unix::net::UnixDatagram::connect_addr`](https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.connect_addr)
- [`std::os::unix::net::UnixDatagram::send_to_addr`](https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.send_to_addr)
- [`std::os::unix::net::UnixListener::bind_addr`](https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixListener.html#method.bind_addr)
- [`std::path::Path::as_mut_os_str`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.as_mut_os_str)
- [`std::sync::OnceLock`](https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html)
Cargo
-----
- [Add `CARGO_PKG_README`](https://github.com/rust-lang/cargo/pull/11645/)
- [Make `sparse` the default protocol for crates.io](https://github.com/rust-lang/cargo/pull/11791/)
- [Accurately show status when downgrading dependencies](https://github.com/rust-lang/cargo/pull/11839/)
- [Use registry.default for login/logout](https://github.com/rust-lang/cargo/pull/11949/)
- [Stabilize `cargo logout`](https://github.com/rust-lang/cargo/pull/11950/)
Misc
----
- [Stabilize rustdoc `--test-run-directory`](https://github.com/rust-lang/rust/pull/103682/)
Compatibility Notes
-------------------
- [Prevent stable `libtest` from supporting `-Zunstable-options`](https://github.com/rust-lang/rust/pull/109044/)
- [Perform const and unsafe checking for expressions in `let _ = expr` position.](https://github.com/rust-lang/rust/pull/102256/)
- [WebAssembly targets enable `sign-ext` and `mutable-globals` features in codegen](https://github.com/rust-lang/rust/issues/109807)
This may cause incompatibility with older execution environments.
- [Insert alignment checks for pointer dereferences as debug assertions](https://github.com/rust-lang/rust/pull/98112)
This catches undefined behavior at runtime, and may cause existing code to fail.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Upgrade to LLVM 16](https://github.com/rust-lang/rust/pull/109474/)
- [Use SipHash-1-3 instead of SipHash-2-4 for StableHasher](https://github.com/rust-lang/rust/pull/107925/)
Version 1.69.0 (2023-04-20)
==========================
Language
--------
- [Deriving built-in traits on packed structs works with `Copy` fields.](https://github.com/rust-lang/rust/pull/104429/)
- [Stabilize the `cmpxchg16b` target feature on x86 and x86_64.](https://github.com/rust-lang/rust/pull/106774/)
- [Improve analysis of trait bounds for associated types.](https://github.com/rust-lang/rust/pull/103695/)
- [Allow associated types to be used as union fields.](https://github.com/rust-lang/rust/pull/106938/)
- [Allow `Self: Autotrait` bounds on dyn-safe trait methods.](https://github.com/rust-lang/rust/pull/107082/)
- [Treat `str` as containing `[u8]` for auto trait purposes.](https://github.com/rust-lang/rust/pull/107941/)
Compiler
--------
- [Upgrade `*-pc-windows-gnu` on CI to mingw-w64 v10 and GCC 12.2.](https://github.com/rust-lang/rust/pull/100178/)
- [Rework min_choice algorithm of member constraints.](https://github.com/rust-lang/rust/pull/105300/)
- [Support `true` and `false` as boolean flags in compiler arguments.](https://github.com/rust-lang/rust/pull/107043/)
- [Default `repr(C)` enums to `c_int` size.](https://github.com/rust-lang/rust/pull/107592/)
Libraries
---------
- [Implement the unstable `DispatchFromDyn` for cell types, allowing downstream experimentation with custom method receivers.](https://github.com/rust-lang/rust/pull/97373/)
- [Document that `fmt::Arguments::as_str()` may return `Some(_)` in more cases after optimization, subject to change.](https://github.com/rust-lang/rust/pull/106823/)
- [Implement `AsFd` and `AsRawFd` for `Rc`.](https://github.com/rust-lang/rust/pull/107317/)
Stabilized APIs
---------------
- [`CStr::from_bytes_until_nul`](https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html#method.from_bytes_until_nul)
- [`core::ffi::FromBytesUntilNulError`](https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesUntilNulError.html)
These APIs are now stable in const contexts:
- [`SocketAddr::new`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.new)
- [`SocketAddr::ip`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.ip)
- [`SocketAddr::port`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.port)
- [`SocketAddr::is_ipv4`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.is_ipv4)
- [`SocketAddr::is_ipv6`](https://doc.rust-lang.org/stable/std/net/enum.SocketAddr.html#method.is_ipv6)
- [`SocketAddrV4::new`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.new)
- [`SocketAddrV4::ip`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.ip)
- [`SocketAddrV4::port`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV4.html#method.port)
- [`SocketAddrV6::new`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.new)
- [`SocketAddrV6::ip`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.ip)
- [`SocketAddrV6::port`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.port)
- [`SocketAddrV6::flowinfo`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.flowinfo)
- [`SocketAddrV6::scope_id`](https://doc.rust-lang.org/stable/std/net/struct.SocketAddrV6.html#method.scope_id)
Cargo
-----
- [Cargo now suggests `cargo fix` or `cargo clippy --fix` when compilation warnings are auto-fixable.](https://github.com/rust-lang/cargo/pull/11558/)
- [Cargo now suggests `cargo add` if you try to install a library crate.](https://github.com/rust-lang/cargo/pull/11410/)
- [Cargo now sets the `CARGO_BIN_NAME` environment variable also for binary examples.](https://github.com/rust-lang/cargo/pull/11705/)
Rustdoc
-----
- [Vertically compact trait bound formatting.](https://github.com/rust-lang/rust/pull/102842/)
- [Only include stable lints in `rustdoc::all` group.](https://github.com/rust-lang/rust/pull/106316/)
- [Compute maximum Levenshtein distance based on the query.](https://github.com/rust-lang/rust/pull/107141/)
- [Remove inconsistently-present sidebar tooltips.](https://github.com/rust-lang/rust/pull/107490/)
- [Search by macro when query ends with `!`.](https://github.com/rust-lang/rust/pull/108143/)
Compatibility Notes
-------------------
- [The `rust-analysis` component from `rustup` now only contains a warning placeholder.](https://github.com/rust-lang/rust/pull/101841/) This was primarily intended for RLS, and the corresponding `-Zsave-analysis` flag has been removed from the compiler as well.
- [Unaligned references to packed fields are now a hard error.](https://github.com/rust-lang/rust/pull/102513/) This has been a warning since 1.53, and denied by default with a future-compatibility warning since 1.62.
- [Update the minimum external LLVM to 14.](https://github.com/rust-lang/rust/pull/107573/)
- [Cargo now emits errors on invalid characters in a registry token.](https://github.com/rust-lang/cargo/pull/11600/)
- [When `default-features` is set to false of a workspace dependency, and an inherited dependency of a member has `default-features = true`, Cargo will enable default features of that dependency.](https://github.com/rust-lang/cargo/pull/11409/)
- [Cargo denies `CARGO_HOME` in the `[env]` configuration table. Cargo itself doesn't pick up this value, but recursive calls to cargo would, which was not intended.](https://github.com/rust-lang/cargo/pull/11644/)
- [Debuginfo for build dependencies is now off if not explicitly set. This is expected to improve the overall build time.](https://github.com/rust-lang/cargo/pull/11252/)
- [The Rust distribution no longer always includes rustdoc](https://github.com/rust-lang/rust/pull/106886)
If `tools = [...]` is set in bootstrap.toml, we will respect a missing rustdoc in that list. By
default rustdoc remains included. To retain the prior behavior explicitly add `"rustdoc"` to the
list.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Move `format_args!()` into AST (and expand it during AST lowering)](https://github.com/rust-lang/rust/pull/106745/)
Version 1.68.2 (2023-03-28)
===========================
- [Update the GitHub RSA host key bundled within Cargo](https://github.com/rust-lang/cargo/pull/11883).
The key was [rotated by GitHub](https://github.blog/2023-03-23-we-updated-our-rsa-ssh-host-key/)
on 2023-03-24 after the old one leaked.
- [Mark the old GitHub RSA host key as revoked](https://github.com/rust-lang/cargo/pull/11889).
This will prevent Cargo from accepting the leaked key even when trusted by
the system.
- [Add support for `@revoked` and a better error message for `@cert-authority` in Cargo's SSH host key verification](https://github.com/rust-lang/cargo/pull/11635)
Version 1.68.1 (2023-03-23)
===========================
- [Fix miscompilation in produced Windows MSVC artifacts](https://github.com/rust-lang/rust/pull/109094)
This was introduced by enabling ThinLTO for the distributed rustc which led
to miscompilations in the resulting binary. Currently this is believed to be
limited to the -Zdylib-lto flag used for rustc compilation, rather than a
general bug in ThinLTO, so only rustc artifacts should be affected.
- [Fix --enable-local-rust builds](https://github.com/rust-lang/rust/pull/109111/)
- [Treat `$prefix-clang` as `clang` in linker detection code](https://github.com/rust-lang/rust/pull/109156)
- [Fix panic in compiler code](https://github.com/rust-lang/rust/pull/108162)
Version 1.68.0 (2023-03-09)
==========================
Language
--------
- [Stabilize default_alloc_error_handler](https://github.com/rust-lang/rust/pull/102318/)
This allows usage of `alloc` on stable without requiring the
definition of a handler for allocation failure. Defining custom handlers is still unstable.
- [Stabilize `efiapi` calling convention.](https://github.com/rust-lang/rust/pull/105795/)
- [Remove implicit promotion for types with drop glue](https://github.com/rust-lang/rust/pull/105085/)
Compiler
--------
- [Change `bindings_with_variant_name` to deny-by-default](https://github.com/rust-lang/rust/pull/104154/)
- [Allow .. to be parsed as let initializer](https://github.com/rust-lang/rust/pull/105701/)
- [Add `armv7-sony-vita-newlibeabihf` as a tier 3 target](https://github.com/rust-lang/rust/pull/105712/)
- [Always check alignment during compile-time const evaluation](https://github.com/rust-lang/rust/pull/104616/)
- [Disable "split dwarf inlining" by default.](https://github.com/rust-lang/rust/pull/106709/)
- [Add vendor to Fuchsia's target triple](https://github.com/rust-lang/rust/pull/106429/)
- [Enable sanitizers for s390x-linux](https://github.com/rust-lang/rust/pull/107127/)
Libraries
---------
- [Loosen the bound on the Debug implementation of Weak.](https://github.com/rust-lang/rust/pull/90291/)
- [Make `std::task::Context` !Send and !Sync](https://github.com/rust-lang/rust/pull/95985/)
- [PhantomData layout guarantees](https://github.com/rust-lang/rust/pull/104081/)
- [Don't derive Debug for `OnceWith` & `RepeatWith`](https://github.com/rust-lang/rust/pull/104163/)
- [Implement DerefMut for PathBuf](https://github.com/rust-lang/rust/pull/105018/)
- [Add O(1) `Vec -> VecDeque` conversion guarantee](https://github.com/rust-lang/rust/pull/105128/)
- [Leak amplification for peek_mut() to ensure BinaryHeap's invariant is always met](https://github.com/rust-lang/rust/pull/105851/)
Stabilized APIs
---------------
- [`{core,std}::pin::pin!`](https://doc.rust-lang.org/stable/std/pin/macro.pin.html)
- [`impl From for {f32,f64}`](https://doc.rust-lang.org/stable/std/primitive.f32.html#impl-From%3Cbool%3E-for-f32)
- [`std::path::MAIN_SEPARATOR_STR`](https://doc.rust-lang.org/stable/std/path/constant.MAIN_SEPARATOR_STR.html)
- [`impl DerefMut for PathBuf`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-DerefMut-for-PathBuf)
These APIs are now stable in const contexts:
- [`VecDeque::new`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.new)
Cargo
-----
- [Stabilize sparse registry support for crates.io](https://github.com/rust-lang/cargo/pull/11224/)
- [`cargo build --verbose` tells you more about why it recompiles.](https://github.com/rust-lang/cargo/pull/11407/)
- [Show progress of crates.io index update even `net.git-fetch-with-cli` option enabled](https://github.com/rust-lang/cargo/pull/11579/)
Misc
----
Compatibility Notes
-------------------
- [Only support Android NDK 25 or newer](https://blog.rust-lang.org/2023/01/09/android-ndk-update-r25.html)
- [Add `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` to future-incompat report](https://github.com/rust-lang/rust/pull/103418/)
- [Only specify `--target` by default for `-Zgcc-ld=lld` on wasm](https://github.com/rust-lang/rust/pull/101792/)
- [Bump `IMPLIED_BOUNDS_ENTAILMENT` to Deny + ReportNow](https://github.com/rust-lang/rust/pull/106465/)
- [`std::task::Context` no longer implements Send and Sync](https://github.com/rust-lang/rust/pull/95985)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Encode spans relative to the enclosing item](https://github.com/rust-lang/rust/pull/84762/)
- [Don't normalize in AstConv](https://github.com/rust-lang/rust/pull/101947/)
- [Find the right lower bound region in the scenario of partial order relations](https://github.com/rust-lang/rust/pull/104765/)
- [Fix impl block in const expr](https://github.com/rust-lang/rust/pull/104889/)
- [Check ADT fields for copy implementations considering regions](https://github.com/rust-lang/rust/pull/105102/)
- [rustdoc: simplify JS search routine by not messing with lev distance](https://github.com/rust-lang/rust/pull/105796/)
- [Enable ThinLTO for rustc on `x86_64-pc-windows-msvc`](https://github.com/rust-lang/rust/pull/103591/)
- [Enable ThinLTO for rustc on `x86_64-apple-darwin`](https://github.com/rust-lang/rust/pull/103647/)
Version 1.67.1 (2023-02-09)
===========================
- [Fix interoperability with thin archives.](https://github.com/rust-lang/rust/pull/107360)
- [Fix an internal error in the compiler build process.](https://github.com/rust-lang/rust/pull/105624)
- [Downgrade `clippy::uninlined_format_args` to pedantic.](https://github.com/rust-lang/rust-clippy/pull/10265)
Version 1.67.0 (2023-01-26)
==========================
Language
--------
- [Make `Sized` predicates coinductive, allowing cycles.](https://github.com/rust-lang/rust/pull/100386/)
- [`#[must_use]` annotations on `async fn` also affect the `Future::Output`.](https://github.com/rust-lang/rust/pull/100633/)
- [Elaborate supertrait obligations when deducing closure signatures.](https://github.com/rust-lang/rust/pull/101834/)
- [Invalid literals are no longer an error under `cfg(FALSE)`.](https://github.com/rust-lang/rust/pull/102944/)
- [Unreserve braced enum variants in value namespace.](https://github.com/rust-lang/rust/pull/103578/)
Compiler
--------
- [Enable varargs support for calling conventions other than `C` or `cdecl`.](https://github.com/rust-lang/rust/pull/97971/)
- [Add new MIR constant propagation based on dataflow analysis.](https://github.com/rust-lang/rust/pull/101168/)
- [Optimize field ordering by grouping m\*2^n-sized fields with equivalently aligned ones.](https://github.com/rust-lang/rust/pull/102750/)
- [Stabilize native library modifier `verbatim`.](https://github.com/rust-lang/rust/pull/104360/)
Added, updated, and removed targets:
- [Add a tier 3 target for PowerPC on AIX](https://github.com/rust-lang/rust/pull/102293/), `powerpc64-ibm-aix`.
- [Add a tier 3 target for the Sony PlayStation 1](https://github.com/rust-lang/rust/pull/102689/), `mipsel-sony-psx`.
- [Add tier 3 `no_std` targets for the QNX Neutrino RTOS](https://github.com/rust-lang/rust/pull/102701/),
`aarch64-unknown-nto-qnx710` and `x86_64-pc-nto-qnx710`.
- [Promote UEFI targets to tier 2](https://github.com/rust-lang/rust/pull/103933/), `aarch64-unknown-uefi`, `i686-unknown-uefi`, and `x86_64-unknown-uefi`.
- [Remove tier 3 `linuxkernel` targets](https://github.com/rust-lang/rust/pull/104015/) (not used by the actual kernel).
Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.
Libraries
---------
- [Merge `crossbeam-channel` into `std::sync::mpsc`.](https://github.com/rust-lang/rust/pull/93563/)
- [Fix inconsistent rounding of 0.5 when formatted to 0 decimal places.](https://github.com/rust-lang/rust/pull/102935/)
- [Derive `Eq` and `Hash` for `ControlFlow`.](https://github.com/rust-lang/rust/pull/103084/)
- [Don't build `compiler_builtins` with `-C panic=abort`.](https://github.com/rust-lang/rust/pull/103786/)
Stabilized APIs
---------------
- [`{integer}::checked_ilog`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog)
- [`{integer}::checked_ilog2`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog2)
- [`{integer}::checked_ilog10`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog10)
- [`{integer}::ilog`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog)
- [`{integer}::ilog2`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog2)
- [`{integer}::ilog10`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog10)
- [`NonZeroU*::ilog2`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#method.ilog2)
- [`NonZeroU*::ilog10`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#method.ilog10)
- [`NonZero*::BITS`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#associatedconstant.BITS)
These APIs are now stable in const contexts:
- [`char::from_u32`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.from_u32)
- [`char::from_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.from_digit)
- [`char::to_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.to_digit)
- [`core::char::from_u32`](https://doc.rust-lang.org/stable/core/char/fn.from_u32.html)
- [`core::char::from_digit`](https://doc.rust-lang.org/stable/core/char/fn.from_digit.html)
Compatibility Notes
-------------------
- [The layout of `repr(Rust)` types now groups m\*2^n-sized fields with
equivalently aligned ones.](https://github.com/rust-lang/rust/pull/102750/)
This is intended to be an optimization, but it is also known to increase type
sizes in a few cases for the placement of enum tags. As a reminder, the layout
of `repr(Rust)` types is an implementation detail, subject to change.
- [0.5 now rounds to 0 when formatted to 0 decimal places.](https://github.com/rust-lang/rust/pull/102935/)
This makes it consistent with the rest of floating point formatting that
rounds ties toward even digits.
- [Chains of `&&` and `||` will now drop temporaries from their sub-expressions in
evaluation order, left-to-right.](https://github.com/rust-lang/rust/pull/103293/)
Previously, it was "twisted" such that the _first_ expression dropped its
temporaries _last_, after all of the other expressions dropped in order.
- [Underscore suffixes on string literals are now a hard error.](https://github.com/rust-lang/rust/pull/103914/)
This has been a future-compatibility warning since 1.20.0.
- [Stop passing `-export-dynamic` to `wasm-ld`.](https://github.com/rust-lang/rust/pull/105405/)
- [`main` is now mangled as `__main_void` on `wasm32-wasi`.](https://github.com/rust-lang/rust/pull/105468/)
- [Cargo now emits an error if there are multiple registries in the configuration
with the same index URL.](https://github.com/rust-lang/cargo/pull/10592)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Rewrite LLVM's archive writer in Rust.](https://github.com/rust-lang/rust/pull/97485/)
Version 1.66.1 (2023-01-10)
===========================
- Added validation of SSH host keys for git URLs in Cargo ([CVE-2022-46176](https://www.cve.org/CVERecord?id=CVE-2022-46176))
Version 1.66.0 (2022-12-15)
==========================
Language
--------
- [Permit specifying explicit discriminants on all `repr(Int)` enums](https://github.com/rust-lang/rust/pull/95710/)
```rust
#[repr(u8)]
enum Foo {
A(u8) = 0,
B(i8) = 1,
C(bool) = 42,
}
```
- [Allow transmutes between the same type differing only in lifetimes](https://github.com/rust-lang/rust/pull/101520/)
- [Change constant evaluation errors from a deny-by-default lint to a hard error](https://github.com/rust-lang/rust/pull/102091/)
- [Trigger `must_use` on `impl Trait` for supertraits](https://github.com/rust-lang/rust/pull/102287/)
This makes `impl ExactSizeIterator` respect the existing `#[must_use]` annotation on `Iterator`.
- [Allow `..=X` in patterns](https://github.com/rust-lang/rust/pull/102275/)
- [Uplift `clippy::for_loops_over_fallibles` lint into rustc](https://github.com/rust-lang/rust/pull/99696/)
- [Stabilize `sym` operands in inline assembly](https://github.com/rust-lang/rust/pull/103168/)
- [Update to Unicode 15](https://github.com/rust-lang/rust/pull/101912/)
- [Opaque types no longer imply lifetime bounds](https://github.com/rust-lang/rust/pull/95474/)
This is a soundness fix which may break code that was erroneously relying on this behavior.
Compiler
--------
- [Add armv5te-none-eabi and thumbv5te-none-eabi tier 3 targets](https://github.com/rust-lang/rust/pull/101329/)
- Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
- [Add support for linking against macOS universal libraries](https://github.com/rust-lang/rust/pull/98736)
Libraries
---------
- [Fix `#[derive(Default)]` on a generic `#[default]` enum adding unnecessary `Default` bounds](https://github.com/rust-lang/rust/pull/101040/)
- [Update to Unicode 15](https://github.com/rust-lang/rust/pull/101821/)
Stabilized APIs
---------------
- [`proc_macro::Span::source_text`](https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.source_text)
- [`uX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}`](https://doc.rust-lang.org/stable/std/primitive.u8.html#method.checked_add_signed)
- [`iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_add_unsigned)
- [`iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}`](https://doc.rust-lang.org/stable/std/primitive.i8.html#method.checked_sub_unsigned)
- [`BTreeSet::{first, last, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.first)
- [`BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.first_key_value)
- [Add `AsFd` implementations for stdio lock types on WASI.](https://github.com/rust-lang/rust/pull/101768/)
- [`impl TryFrom> for Box<[T; N]>`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#impl-TryFrom%3CVec%3CT%2C%20Global%3E%3E-for-Box%3C%5BT%3B%20N%5D%2C%20Global%3E)
- [`core::hint::black_box`](https://doc.rust-lang.org/stable/std/hint/fn.black_box.html)
- [`Duration::try_from_secs_{f32,f64}`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.try_from_secs_f32)
- [`Option::unzip`](https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.unzip)
- [`std::os::fd`](https://doc.rust-lang.org/stable/std/os/fd/index.html)
Rustdoc
-------
- [Add Rustdoc warning for invalid HTML tags in the documentation](https://github.com/rust-lang/rust/pull/101720/)
Cargo
-----
- [Added `cargo remove` to remove dependencies from Cargo.toml](https://doc.rust-lang.org/nightly/cargo/commands/cargo-remove.html)
- [`cargo publish` now waits for the new version to be downloadable before exiting](https://github.com/rust-lang/cargo/pull/11062)
See [detailed release notes](https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-166-2022-12-15) for more.
Compatibility Notes
-------------------
- [Only apply `ProceduralMasquerade` hack to older versions of `rental`](https://github.com/rust-lang/rust/pull/94063/)
- [Don't export `__heap_base` and `__data_end` on wasm32-wasi.](https://github.com/rust-lang/rust/pull/102385/)
- [Don't export `__wasm_init_memory` on WebAssembly.](https://github.com/rust-lang/rust/pull/102426/)
- [Only export `__tls_*` on wasm32-unknown-unknown.](https://github.com/rust-lang/rust/pull/102440/)
- [Don't link to `libresolv` in libstd on Darwin](https://github.com/rust-lang/rust/pull/102766/)
- [Update libstd's libc to 0.2.135 (to make `libstd` no longer pull in `libiconv.dylib` on Darwin)](https://github.com/rust-lang/rust/pull/103277/)
- [Opaque types no longer imply lifetime bounds](https://github.com/rust-lang/rust/pull/95474/)
This is a soundness fix which may break code that was erroneously relying on this behavior.
- [Make `order_dependent_trait_objects` show up in future-breakage reports](https://github.com/rust-lang/rust/pull/102635/)
- [Change std::process::Command spawning to default to inheriting the parent's signal mask](https://github.com/rust-lang/rust/pull/101077/)
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Enable BOLT for LLVM compilation](https://github.com/rust-lang/rust/pull/94381/)
- [Enable LTO for rustc_driver.so](https://github.com/rust-lang/rust/pull/101403/)
Version 1.65.0 (2022-11-03)
==========================
Language
--------
- [Error on `as` casts of enums with `#[non_exhaustive]` variants](https://github.com/rust-lang/rust/pull/92744/)
- [Stabilize `let else`](https://github.com/rust-lang/rust/pull/93628/)
- [Stabilize generic associated types (GATs)](https://github.com/rust-lang/rust/pull/96709/)
- [Add lints `let_underscore_drop` and `let_underscore_lock` from Clippy](https://github.com/rust-lang/rust/pull/97739/)
- [Stabilize `break`ing from arbitrary labeled blocks ("label-break-value")](https://github.com/rust-lang/rust/pull/99332/)
- [Uninitialized integers, floats, and raw pointers are now considered immediate UB](https://github.com/rust-lang/rust/pull/98919/).
Usage of `MaybeUninit` is the correct way to work with uninitialized memory.
- [Stabilize raw-dylib for Windows x86_64, aarch64, and thumbv7a](https://github.com/rust-lang/rust/pull/99916/)
- [Do not allow `Drop` impl on foreign ADTs](https://github.com/rust-lang/rust/pull/99576/)
Compiler
--------
- [Stabilize -Csplit-debuginfo on Linux](https://github.com/rust-lang/rust/pull/98051/)
- [Use niche-filling optimization even when multiple variants have data](https://github.com/rust-lang/rust/pull/94075/)
- [Associated type projections are now verified to be well-formed prior to resolving the underlying type](https://github.com/rust-lang/rust/pull/99217/#issuecomment-1209365630)
- [Stringify non-shorthand visibility correctly](https://github.com/rust-lang/rust/pull/100350/)
- [Normalize struct field types when unsizing](https://github.com/rust-lang/rust/pull/101831/)
- [Update to LLVM 15](https://github.com/rust-lang/rust/pull/99464/)
- [Fix aarch64 call abi to correctly zeroext when needed](https://github.com/rust-lang/rust/pull/97800/)
- [debuginfo: Generalize C++-like encoding for enums](https://github.com/rust-lang/rust/pull/98393/)
- [Add `special_module_name` lint](https://github.com/rust-lang/rust/pull/94467/)
- [Add support for generating unique profraw files by default when using `-C instrument-coverage`](https://github.com/rust-lang/rust/pull/100384/)
- [Allow dynamic linking for iOS/tvOS targets](https://github.com/rust-lang/rust/pull/100636/)
New targets:
- [Add armv4t-none-eabi as a tier 3 target](https://github.com/rust-lang/rust/pull/100244/)
- [Add powerpc64-unknown-openbsd and riscv64-unknown-openbsd as tier 3 targets](https://github.com/rust-lang/rust/pull/101025/)
- Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Don't generate `PartialEq::ne` in derive(PartialEq)](https://github.com/rust-lang/rust/pull/98655/)
- [Windows RNG: Use `BCRYPT_RNG_ALG_HANDLE` by default](https://github.com/rust-lang/rust/pull/101325/)
- [Forbid mixing `System` with direct system allocator calls](https://github.com/rust-lang/rust/pull/101394/)
- [Document no support for writing to non-blocking stdio/stderr](https://github.com/rust-lang/rust/pull/101416/)
- [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`](https://github.com/rust-lang/rust/pull/95295)
This also changes the safety conditions on `Layout::from_size_align_unchecked`.
Stabilized APIs
---------------
- [`std::backtrace::Backtrace`](https://doc.rust-lang.org/stable/std/backtrace/struct.Backtrace.html)
- [`Bound::as_ref`](https://doc.rust-lang.org/stable/std/ops/enum.Bound.html#method.as_ref)
- [`std::io::read_to_string`](https://doc.rust-lang.org/stable/std/io/fn.read_to_string.html)
- [`<*const T>::cast_mut`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_mut)
- [`<*mut T>::cast_const`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.cast_const)
These APIs are now stable in const contexts:
- [`<*const T>::offset_from`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from)
- [`<*mut T>::offset_from`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset_from)
Cargo
-----
- [Apply GitHub fast path even for partial hashes](https://github.com/rust-lang/cargo/pull/10807/)
- [Do not add home bin path to PATH if it's already there](https://github.com/rust-lang/cargo/pull/11023/)
- [Take priority into account within the pending queue](https://github.com/rust-lang/cargo/pull/11032/).
This slightly optimizes job scheduling by Cargo, with typically small improvements on larger crate graph builds.
Compatibility Notes
-------------------
- [`std::layout::Layout` size must not overflow `isize::MAX` when rounded up to `align`](https://github.com/rust-lang/rust/pull/95295).
This also changes the safety conditions on `Layout::from_size_align_unchecked`.
- [`PollFn` now only implements `Unpin` if the closure is `Unpin`](https://github.com/rust-lang/rust/pull/102737).
This is a possible breaking change if users were relying on the blanket unpin implementation.
See discussion on the PR for details of why this change was made.
- [Drop ExactSizeIterator impl from std::char::EscapeAscii](https://github.com/rust-lang/rust/pull/99880)
This is a backwards-incompatible change to the standard library's surface
area, but is unlikely to affect real world usage.
- [Do not consider a single repeated lifetime eligible for elision in the return type](https://github.com/rust-lang/rust/pull/103450)
This behavior was unintentionally changed in 1.64.0, and this release reverts that change by making this an error again.
- [Reenable disabled early syntax gates as future-incompatibility lints](https://github.com/rust-lang/rust/pull/99935/)
- [Update the minimum external LLVM to 13](https://github.com/rust-lang/rust/pull/100460/)
- [Don't duplicate file descriptors into stdio fds](https://github.com/rust-lang/rust/pull/101426/)
- [Sunset RLS](https://github.com/rust-lang/rust/pull/100863/)
- [Deny usage of `#![cfg_attr(..., crate_type = ...)]` to set the crate type](https://github.com/rust-lang/rust/pull/99784/)
This strengthens the forward compatibility lint deprecated_cfg_attr_crate_type_name to deny.
- [`llvm-has-rust-patches` allows setting the build system to treat the LLVM as having Rust-specific patches](https://github.com/rust-lang/rust/pull/101072)
This option may need to be set for distributions that are building Rust with a patched LLVM via `llvm-config`, not the built-in LLVM.
- Combining three or more languages (e.g. Objective C, C++ and Rust) into one binary may hit linker limitations when using `lld`. For more information, see [issue 102754][102754].
[102754]: https://github.com/rust-lang/rust/issues/102754
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- [Add `x.sh` and `x.ps1` shell scripts](https://github.com/rust-lang/rust/pull/99992/)
- [compiletest: use target cfg instead of hard-coded tables](https://github.com/rust-lang/rust/pull/100260/)
- [Use object instead of LLVM for reading bitcode from rlibs](https://github.com/rust-lang/rust/pull/98100/)
- [Enable MIR inlining for optimized compilations](https://github.com/rust-lang/rust/pull/91743)
This provides a 3-10% improvement in compiletimes for real world crates. See [perf results](https://perf.rust-lang.org/compare.html?start=aedf78e56b2279cc869962feac5153b6ba7001ed&end=0075bb4fad68e64b6d1be06bf2db366c30bc75e1&stat=instructions:u).
Version 1.64.0 (2022-09-22)
===========================
Language
--------
- [Unions with mutable references or tuples of allowed types are now allowed](https://github.com/rust-lang/rust/pull/97995/)
- It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](https://github.com/rust-lang/rust/pull/98017/)
- Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`](https://github.com/rust-lang/rust/pull/95977/), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future.
Compiler
--------
- [Add Nintendo Switch as tier 3 target](https://github.com/rust-lang/rust/pull/88991/)
- Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
- [Only compile `#[used]` as llvm.compiler.used for ELF targets](https://github.com/rust-lang/rust/pull/93718/)
- [Add the `--diagnostic-width` compiler flag to define the terminal width.](https://github.com/rust-lang/rust/pull/95635/)
- [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS](https://github.com/rust-lang/rust/pull/98771/)
Libraries
---------
- [Remove restrictions on compare-exchange memory ordering.](https://github.com/rust-lang/rust/pull/98383/)
- You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](https://github.com/rust-lang/rust/pull/97915/)
- [Make RwLockReadGuard covariant](https://github.com/rust-lang/rust/pull/96820/)
- [Implement `FusedIterator` for `std::net::[Into]Incoming`](https://github.com/rust-lang/rust/pull/97300/)
- [`impl AsRawFd for {Arc,Box}`](https://github.com/rust-lang/rust/pull/97437/)
- [`ptr::copy` and `ptr::swap` are doing untyped copies](https://github.com/rust-lang/rust/pull/97712/)
- [Add cgroupv1 support to `available_parallelism`](https://github.com/rust-lang/rust/pull/97925/)
- [Mitigate many incorrect uses of `mem::uninitialized`](https://github.com/rust-lang/rust/pull/99182/)
Stabilized APIs
---------------
- [`future::IntoFuture`](https://doc.rust-lang.org/stable/std/future/trait.IntoFuture.html)
- [`future::poll_fn`](https://doc.rust-lang.org/stable/std/future/fn.poll_fn.html)
- [`task::ready!`](https://doc.rust-lang.org/stable/std/task/macro.ready.html)
- [`num::NonZero*::checked_mul`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_mul)
- [`num::NonZero*::checked_pow`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_pow)
- [`num::NonZero*::saturating_mul`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_mul)
- [`num::NonZero*::saturating_pow`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_pow)
- [`num::NonZeroI*::abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.abs)
- [`num::NonZeroI*::checked_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.checked_abs)
- [`num::NonZeroI*::overflowing_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.overflowing_abs)
- [`num::NonZeroI*::saturating_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.saturating_abs)
- [`num::NonZeroI*::unsigned_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.unsigned_abs)
- [`num::NonZeroI*::wrapping_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.wrapping_abs)
- [`num::NonZeroU*::checked_add`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_add)
- [`num::NonZeroU*::checked_next_power_of_two`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_next_power_of_two)
- [`num::NonZeroU*::saturating_add`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_add)
- [`os::unix::process::CommandExt::process_group`](https://doc.rust-lang.org/stable/std/os/unix/process/trait.CommandExt.html#tymethod.process_group)
- [`os::windows::fs::FileTypeExt::is_symlink_dir`](https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_dir)
- [`os::windows::fs::FileTypeExt::is_symlink_file`](https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_file)
These types were previously stable in `std::ffi`, but are now also available in `core` and `alloc`:
- [`core::ffi::CStr`](https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html)
- [`core::ffi::FromBytesWithNulError`](https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesWithNulError.html)
- [`alloc::ffi::CString`](https://doc.rust-lang.org/stable/alloc/ffi/struct.CString.html)
- [`alloc::ffi::FromVecWithNulError`](https://doc.rust-lang.org/stable/alloc/ffi/struct.FromVecWithNulError.html)
- [`alloc::ffi::IntoStringError`](https://doc.rust-lang.org/stable/alloc/ffi/struct.IntoStringError.html)
- [`alloc::ffi::NulError`](https://doc.rust-lang.org/stable/alloc/ffi/struct.NulError.html)
These types were previously stable in `std::os::raw`, but are now also available in `core::ffi` and `std::ffi`:
- [`ffi::c_char`](https://doc.rust-lang.org/stable/std/ffi/type.c_char.html)
- [`ffi::c_double`](https://doc.rust-lang.org/stable/std/ffi/type.c_double.html)
- [`ffi::c_float`](https://doc.rust-lang.org/stable/std/ffi/type.c_float.html)
- [`ffi::c_int`](https://doc.rust-lang.org/stable/std/ffi/type.c_int.html)
- [`ffi::c_long`](https://doc.rust-lang.org/stable/std/ffi/type.c_long.html)
- [`ffi::c_longlong`](https://doc.rust-lang.org/stable/std/ffi/type.c_longlong.html)
- [`ffi::c_schar`](https://doc.rust-lang.org/stable/std/ffi/type.c_schar.html)
- [`ffi::c_short`](https://doc.rust-lang.org/stable/std/ffi/type.c_short.html)
- [`ffi::c_uchar`](https://doc.rust-lang.org/stable/std/ffi/type.c_uchar.html)
- [`ffi::c_uint`](https://doc.rust-lang.org/stable/std/ffi/type.c_uint.html)
- [`ffi::c_ulong`](https://doc.rust-lang.org/stable/std/ffi/type.c_ulong.html)
- [`ffi::c_ulonglong`](https://doc.rust-lang.org/stable/std/ffi/type.c_ulonglong.html)
- [`ffi::c_ushort`](https://doc.rust-lang.org/stable/std/ffi/type.c_ushort.html)
These APIs are now usable in const contexts:
- [`slice::from_raw_parts`](https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts.html)
Cargo
-----
- [Packages can now inherit settings from the workspace so that the settings
can be centralized in one place.](https://github.com/rust-lang/cargo/pull/10859) See
[`workspace.package`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacepackage-table)
and
[`workspace.dependencies`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacedependencies-table)
for more details on how to define these common settings.
- [Cargo commands can now accept multiple `--target` flags to build for
multiple targets at once](https://github.com/rust-lang/cargo/pull/10766), and the
[`build.target`](https://doc.rust-lang.org/nightly/cargo/reference/config.html#buildtarget)
config option may now take an array of multiple targets.
- [The `--jobs` argument can now take a negative number to count backwards from
the max CPUs.](https://github.com/rust-lang/cargo/pull/10844)
- [`cargo add` will now update `Cargo.lock`.](https://github.com/rust-lang/cargo/pull/10902)
- [Added](https://github.com/rust-lang/cargo/pull/10838) the
[`--crate-type`](https://doc.rust-lang.org/nightly/cargo/commands/cargo-rustc.html#option-cargo-rustc---crate-type)
flag to `cargo rustc` to override the crate type.
- [Significantly improved the performance fetching git dependencies from GitHub
when using a hash in the `rev` field.](https://github.com/rust-lang/cargo/pull/10079)
Misc
----
- [The `rust-analyzer` rustup component is now available on the stable channel.](https://github.com/rust-lang/rust/pull/98640/)
Compatibility Notes
-------------------
- The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](https://github.com/rust-lang/rust/pull/95026/)
- [Network primitives are now implemented with the ideal Rust layout, not the C system layout](https://github.com/rust-lang/rust/pull/78802/). This can cause problems when transmuting the types.
- [Add assertion that `transmute_copy`'s `U` is not larger than `T`](https://github.com/rust-lang/rust/pull/98839/)
- [A soundness bug in `BTreeMap` was fixed](https://github.com/rust-lang/rust/pull/99413/) that allowed data it was borrowing to be dropped before the container.
- [The Drop behavior of C-like enums cast to ints has changed](https://github.com/rust-lang/rust/pull/96862/). These are already discouraged by a compiler warning.
- [Relate late-bound closure lifetimes to parent fn in NLL](https://github.com/rust-lang/rust/pull/98835/)
- [Errors at const-eval time are now in future incompatibility reports](https://github.com/rust-lang/rust/pull/97743/)
- On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted](https://github.com/rust-lang/rust/pull/99155/).
- [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`](https://github.com/rust-lang/rust/pull/97346/), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed.
Internal Changes
----------------
These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.
- Windows builds now use profile-guided optimization, providing 10-20% improvements to compiler performance: [Utilize PGO for windows x64 rustc dist builds](https://github.com/rust-lang/rust/pull/96978/)
- [Stop keeping metadata in memory before writing it to disk](https://github.com/rust-lang/rust/pull/96544/)
- [compiletest: strip debuginfo by default for mode=ui](https://github.com/rust-lang/rust/pull/98140/)
- Many improvements to generated code for derives, including performance improvements:
- [Don't use match-destructuring for derived ops on structs.](https://github.com/rust-lang/rust/pull/98446/)
- [Many small deriving cleanups](https://github.com/rust-lang/rust/pull/98741/)
- [More derive output improvements](https://github.com/rust-lang/rust/pull/98758/)
- [Clarify deriving code](https://github.com/rust-lang/rust/pull/98915/)
- [Final derive output improvements](https://github.com/rust-lang/rust/pull/99046/)
- [Stop injecting `#[allow(unused_qualifications)]` in generated `derive` implementations](https://github.com/rust-lang/rust/pull/99485/)
- [Improve `derive(Debug)`](https://github.com/rust-lang/rust/pull/98190/)
- [Bump to clap 3](https://github.com/rust-lang/rust/pull/98213/)
- [fully move dropck to mir](https://github.com/rust-lang/rust/pull/98641/)
- [Optimize `Vec::insert` for the case where `index == len`.](https://github.com/rust-lang/rust/pull/98755/)
- [Convert rust-analyzer to an in-tree tool](https://github.com/rust-lang/rust/pull/99603/)
Version 1.63.0 (2022-08-11)
==========================
Language
--------
- [Remove migrate borrowck mode for pre-NLL errors.][95565]
- [Modify MIR building to drop repeat expressions with length zero.][95953]
- [Remove label/lifetime shadowing warnings.][96296]
- [Allow explicit generic arguments in the presence of `impl Trait` args.][96868]
- [Make `cenum_impl_drop_cast` warnings deny-by-default.][97652]
- [Prevent unwinding when `-C panic=abort` is used regardless of declared ABI.][96959]
- [lub: don't bail out due to empty binders.][97867]
Compiler
--------
- [Stabilize the `bundle` native library modifier,][95818] also removing the
deprecated `static-nobundle` linking kind.
- [Add Apple WatchOS compile targets\*.][95243]
- [Add a Windows application manifest to rustc-main.][96737]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Implement `Copy`, `Clone`, `PartialEq` and `Eq` for `core::fmt::Alignment`.][94530]
- [Extend `ptr::null` and `null_mut` to all thin (including extern) types.][94954]
- [`impl Read and Write for VecDeque`.][95632]
- [STD support for the Nintendo 3DS.][95897]
- [Use rounding in float to Duration conversion methods.][96051]
- [Make write/print macros eagerly drop temporaries.][96455]
- [Implement internal traits that enable `[OsStr]::join`.][96881]
- [Implement `Hash` for `core::alloc::Layout`.][97034]
- [Add capacity documentation for `OsString`.][97202]
- [Put a bound on collection misbehavior.][97316]
- [Make `std::mem::needs_drop` accept `?Sized`.][97675]
- [`impl Termination for Infallible` and then make the `Result` impls of `Termination` more generic.][97803]
- [Document Rust's stance on `/proc/self/mem`.][97837]
Stabilized APIs
---------------
- [`array::from_fn`]
- [`Box::into_pin`]
- [`BinaryHeap::try_reserve`]
- [`BinaryHeap::try_reserve_exact`]
- [`OsString::try_reserve`]
- [`OsString::try_reserve_exact`]
- [`PathBuf::try_reserve`]
- [`PathBuf::try_reserve_exact`]
- [`Path::try_exists`]
- [`Ref::filter_map`]
- [`RefMut::filter_map`]
- [`NonNull::<[T]>::len`][`NonNull::::len`]
- [`ToOwned::clone_into`]
- [`Ipv6Addr::to_ipv4_mapped`]
- [`unix::io::AsFd`]
- [`unix::io::BorrowedFd<'fd>`]
- [`unix::io::OwnedFd`]
- [`windows::io::AsHandle`]
- [`windows::io::BorrowedHandle<'handle>`]
- [`windows::io::OwnedHandle`]
- [`windows::io::HandleOrInvalid`]
- [`windows::io::HandleOrNull`]
- [`windows::io::InvalidHandleError`]
- [`windows::io::NullHandleError`]
- [`windows::io::AsSocket`]
- [`windows::io::BorrowedSocket<'handle>`]
- [`windows::io::OwnedSocket`]
- [`thread::scope`]
- [`thread::Scope`]
- [`thread::ScopedJoinHandle`]
These APIs are now usable in const contexts:
- [`array::from_ref`]
- [`slice::from_ref`]
- [`intrinsics::copy`]
- [`intrinsics::copy_nonoverlapping`]
- [`<*const T>::copy_to`]
- [`<*const T>::copy_to_nonoverlapping`]
- [`<*mut T>::copy_to`]
- [`<*mut T>::copy_to_nonoverlapping`]
- [`<*mut T>::copy_from`]
- [`<*mut T>::copy_from_nonoverlapping`]
- [`str::from_utf8`]
- [`Utf8Error::error_len`]
- [`Utf8Error::valid_up_to`]
- [`Condvar::new`]
- [`Mutex::new`]
- [`RwLock::new`]
Cargo
-----
- [Stabilize the `--config path` command-line argument.][cargo/10755]
- [Expose rust-version in the environment as `CARGO_PKG_RUST_VERSION`.][cargo/10713]
Compatibility Notes
-------------------
- [`#[link]` attributes are now checked more strictly,][96885] which may introduce
errors for invalid attribute arguments that were previously ignored.
- [Rounding is now used when converting a float to a `Duration`.][96051] The converted
duration can differ slightly from what it was.
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.
- [Prepare Rust for LLVM opaque pointers.][94214]
[94214]: https://github.com/rust-lang/rust/pull/94214/
[94530]: https://github.com/rust-lang/rust/pull/94530/
[94954]: https://github.com/rust-lang/rust/pull/94954/
[95243]: https://github.com/rust-lang/rust/pull/95243/
[95565]: https://github.com/rust-lang/rust/pull/95565/
[95632]: https://github.com/rust-lang/rust/pull/95632/
[95818]: https://github.com/rust-lang/rust/pull/95818/
[95897]: https://github.com/rust-lang/rust/pull/95897/
[95953]: https://github.com/rust-lang/rust/pull/95953/
[96051]: https://github.com/rust-lang/rust/pull/96051/
[96296]: https://github.com/rust-lang/rust/pull/96296/
[96455]: https://github.com/rust-lang/rust/pull/96455/
[96737]: https://github.com/rust-lang/rust/pull/96737/
[96868]: https://github.com/rust-lang/rust/pull/96868/
[96881]: https://github.com/rust-lang/rust/pull/96881/
[96885]: https://github.com/rust-lang/rust/pull/96885/
[96959]: https://github.com/rust-lang/rust/pull/96959/
[97034]: https://github.com/rust-lang/rust/pull/97034/
[97202]: https://github.com/rust-lang/rust/pull/97202/
[97316]: https://github.com/rust-lang/rust/pull/97316/
[97652]: https://github.com/rust-lang/rust/pull/97652/
[97675]: https://github.com/rust-lang/rust/pull/97675/
[97803]: https://github.com/rust-lang/rust/pull/97803/
[97837]: https://github.com/rust-lang/rust/pull/97837/
[97867]: https://github.com/rust-lang/rust/pull/97867/
[cargo/10713]: https://github.com/rust-lang/cargo/pull/10713/
[cargo/10755]: https://github.com/rust-lang/cargo/pull/10755/
[`array::from_fn`]: https://doc.rust-lang.org/stable/std/array/fn.from_fn.html
[`Box::into_pin`]: https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.into_pin
[`BinaryHeap::try_reserve_exact`]: https://doc.rust-lang.org/stable/alloc/collections/binary_heap/struct.BinaryHeap.html#method.try_reserve_exact
[`BinaryHeap::try_reserve`]: https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.try_reserve
[`OsString::try_reserve`]: https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.try_reserve
[`OsString::try_reserve_exact`]: https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.try_reserve_exact
[`PathBuf::try_reserve`]: https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.try_reserve
[`PathBuf::try_reserve_exact`]: https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.try_reserve_exact
[`Path::try_exists`]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.try_exists
[`Ref::filter_map`]: https://doc.rust-lang.org/stable/std/cell/struct.Ref.html#method.filter_map
[`RefMut::filter_map`]: https://doc.rust-lang.org/stable/std/cell/struct.RefMut.html#method.filter_map
[`NonNull::::len`]: https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.len
[`ToOwned::clone_into`]: https://doc.rust-lang.org/stable/std/borrow/trait.ToOwned.html#method.clone_into
[`Ipv6Addr::to_ipv4_mapped`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.to_ipv4_mapped
[`unix::io::AsFd`]: https://doc.rust-lang.org/stable/std/os/unix/io/trait.AsFd.html
[`unix::io::BorrowedFd<'fd>`]: https://doc.rust-lang.org/stable/std/os/unix/io/struct.BorrowedFd.html
[`unix::io::OwnedFd`]: https://doc.rust-lang.org/stable/std/os/unix/io/struct.OwnedFd.html
[`windows::io::AsHandle`]: https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsHandle.html
[`windows::io::BorrowedHandle<'handle>`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.BorrowedHandle.html
[`windows::io::OwnedHandle`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.OwnedHandle.html
[`windows::io::HandleOrInvalid`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.HandleOrInvalid.html
[`windows::io::HandleOrNull`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.HandleOrNull.html
[`windows::io::InvalidHandleError`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.InvalidHandleError.html
[`windows::io::NullHandleError`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.NullHandleError.html
[`windows::io::AsSocket`]: https://doc.rust-lang.org/stable/std/os/windows/io/trait.AsSocket.html
[`windows::io::BorrowedSocket<'handle>`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.BorrowedSocket.html
[`windows::io::OwnedSocket`]: https://doc.rust-lang.org/stable/std/os/windows/io/struct.OwnedSocket.html
[`thread::scope`]: https://doc.rust-lang.org/stable/std/thread/fn.scope.html
[`thread::Scope`]: https://doc.rust-lang.org/stable/std/thread/struct.Scope.html
[`thread::ScopedJoinHandle`]: https://doc.rust-lang.org/stable/std/thread/struct.ScopedJoinHandle.html
[`array::from_ref`]: https://doc.rust-lang.org/stable/std/array/fn.from_ref.html
[`slice::from_ref`]: https://doc.rust-lang.org/stable/std/slice/fn.from_ref.html
[`intrinsics::copy`]: https://doc.rust-lang.org/stable/std/intrinsics/fn.copy.html
[`intrinsics::copy_nonoverlapping`]: https://doc.rust-lang.org/stable/std/intrinsics/fn.copy_nonoverlapping.html
[`<*const T>::copy_to`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.copy_to
[`<*const T>::copy_to_nonoverlapping`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.copy_to_nonoverlapping
[`<*mut T>::copy_to`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.copy_to-1
[`<*mut T>::copy_to_nonoverlapping`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.copy_to_nonoverlapping-1
[`<*mut T>::copy_from`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.copy_from
[`<*mut T>::copy_from_nonoverlapping`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.copy_from_nonoverlapping
[`str::from_utf8`]: https://doc.rust-lang.org/stable/std/str/fn.from_utf8.html
[`Utf8Error::error_len`]: https://doc.rust-lang.org/stable/std/str/struct.Utf8Error.html#method.error_len
[`Utf8Error::valid_up_to`]: https://doc.rust-lang.org/stable/std/str/struct.Utf8Error.html#method.valid_up_to
[`Condvar::new`]: https://doc.rust-lang.org/stable/std/sync/struct.Condvar.html#method.new
[`Mutex::new`]: https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.new
[`RwLock::new`]: https://doc.rust-lang.org/stable/std/sync/struct.RwLock.html#method.new
Version 1.62.1 (2022-07-19)
==========================
Rust 1.62.1 addresses a few recent regressions in the compiler and standard
library, and also mitigates a CPU vulnerability on Intel SGX.
* [The compiler fixed unsound function coercions involving `impl Trait` return types.][98608]
* [The compiler fixed an incremental compilation bug with `async fn` lifetimes.][98890]
* [Windows added a fallback for overlapped I/O in synchronous reads and writes.][98950]
* [The `x86_64-fortanix-unknown-sgx` target added a mitigation for the
MMIO stale data vulnerability][98126], advisory [INTEL-SA-00615].
[98608]: https://github.com/rust-lang/rust/issues/98608
[98890]: https://github.com/rust-lang/rust/issues/98890
[98950]: https://github.com/rust-lang/rust/pull/98950
[98126]: https://github.com/rust-lang/rust/pull/98126
[INTEL-SA-00615]: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00615.html
Version 1.62.0 (2022-06-30)
==========================
Language
--------
- [Stabilize `#[derive(Default)]` on enums with a `#[default]` variant][94457]
- [Teach flow sensitive checks that visibly uninhabited call expressions never return][93313]
- [Fix constants not getting dropped if part of a diverging expression][94775]
- [Support unit struct/enum variant in destructuring assignment][95380]
- [Remove mutable_borrow_reservation_conflict lint and allow the code pattern][96268]
- [`const` functions may now specify `extern "C"` or `extern "Rust"`][95346]
Compiler
--------
- [linker: Stop using whole-archive on dependencies of dylibs][96436]
- [Make `unaligned_references` lint deny-by-default][95372]
This lint is also a future compatibility lint, and is expected to eventually
become a hard error.
- [Only add codegen backend to dep info if -Zbinary-dep-depinfo is used][93969]
- [Reject `#[thread_local]` attribute on non-static items][95006]
- [Add tier 3 `aarch64-pc-windows-gnullvm` and `x86_64-pc-windows-gnullvm` targets\*][94872]
- [Implement a lint to warn about unused macro rules][96150]
- [Promote `x86_64-unknown-none` target to Tier 2\*][95705]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Windows: Use a pipe relay for chaining pipes][95841]
- [Replace Linux Mutex and Condvar with futex based ones.][95035]
- [Replace RwLock by a futex based one on Linux][95801]
- [std: directly use pthread in UNIX parker implementation][96393]
Stabilized APIs
---------------
- [`bool::then_some`]
- [`f32::total_cmp`]
- [`f64::total_cmp`]
- [`Stdin::lines`]
- [`windows::CommandExt::raw_arg`]
- [`impl Default for AssertUnwindSafe`]
- [`From> for Rc<[u8]>`][rc-u8-from-str]
- [`From> for Arc<[u8]>`][arc-u8-from-str]
- [`FusedIterator for EncodeWide`]
- [RDM intrinsics on aarch64][stdarch/1285]
Clippy
------
- [Create clippy lint against unexpectedly late drop for temporaries in match scrutinee expressions][94206]
Cargo
-----
- Added the `cargo add` command for adding dependencies to `Cargo.toml` from
the command-line.
[docs](https://doc.rust-lang.org/nightly/cargo/commands/cargo-add.html)
- Package ID specs now support `name@version` syntax in addition to the
previous `name:version` to align with the behavior in `cargo add` and other
tools. `cargo install` and `cargo yank` also now support this syntax so the
version does not need to passed as a separate flag.
- The `git` and `registry` directories in Cargo's home directory (usually
`~/.cargo`) are now marked as cache directories so that they are not
included in backups or content indexing (on Windows).
- Added automatic `@` argfile support, which will use "response files" if the
command-line to `rustc` exceeds the operating system's limit.
Compatibility Notes
-------------------
- `cargo test` now passes `--target` to `rustdoc` if the specified target is
the same as the host target.
[#10594](https://github.com/rust-lang/cargo/pull/10594)
- [rustdoc: doctests are now run on unexported `macro_rules!` macros, matching other private items][96630]
- [rustdoc: Remove .woff font files][96279]
- [Enforce Copy bounds for repeat elements while considering lifetimes][95819]
- [Windows: Fix potential unsoundness by aborting if `File` reads or writes cannot
complete synchronously][95469].
Internal Changes
----------------
- [Unify ReentrantMutex implementations across all platforms][96042]
These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.
[93313]: https://github.com/rust-lang/rust/pull/93313/
[93969]: https://github.com/rust-lang/rust/pull/93969/
[94206]: https://github.com/rust-lang/rust/pull/94206/
[94457]: https://github.com/rust-lang/rust/pull/94457/
[94775]: https://github.com/rust-lang/rust/pull/94775/
[94872]: https://github.com/rust-lang/rust/pull/94872/
[95006]: https://github.com/rust-lang/rust/pull/95006/
[95035]: https://github.com/rust-lang/rust/pull/95035/
[95346]: https://github.com/rust-lang/rust/pull/95346/
[95372]: https://github.com/rust-lang/rust/pull/95372/
[95380]: https://github.com/rust-lang/rust/pull/95380/
[95431]: https://github.com/rust-lang/rust/pull/95431/
[95469]: https://github.com/rust-lang/rust/pull/95469/
[95705]: https://github.com/rust-lang/rust/pull/95705/
[95801]: https://github.com/rust-lang/rust/pull/95801/
[95819]: https://github.com/rust-lang/rust/pull/95819/
[95841]: https://github.com/rust-lang/rust/pull/95841/
[96042]: https://github.com/rust-lang/rust/pull/96042/
[96150]: https://github.com/rust-lang/rust/pull/96150/
[96268]: https://github.com/rust-lang/rust/pull/96268/
[96279]: https://github.com/rust-lang/rust/pull/96279/
[96393]: https://github.com/rust-lang/rust/pull/96393/
[96436]: https://github.com/rust-lang/rust/pull/96436/
[96557]: https://github.com/rust-lang/rust/pull/96557/
[96630]: https://github.com/rust-lang/rust/pull/96630/
[`bool::then_some`]: https://doc.rust-lang.org/stable/std/primitive.bool.html#method.then_some
[`f32::total_cmp`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.total_cmp
[`f64::total_cmp`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.total_cmp
[`Stdin::lines`]: https://doc.rust-lang.org/stable/std/io/struct.Stdin.html#method.lines
[`impl Default for AssertUnwindSafe`]: https://doc.rust-lang.org/stable/std/panic/struct.AssertUnwindSafe.html#impl-Default
[rc-u8-from-str]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#impl-From%3CRc%3Cstr%3E%3E
[arc-u8-from-str]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#impl-From%3CArc%3Cstr%3E%3E
[stdarch/1285]: https://github.com/rust-lang/stdarch/pull/1285
[`windows::CommandExt::raw_arg`]: https://doc.rust-lang.org/stable/std/os/windows/process/trait.CommandExt.html#tymethod.raw_arg
[`FusedIterator for EncodeWide`]: https://doc.rust-lang.org/stable/std/os/windows/ffi/struct.EncodeWide.html#impl-FusedIterator
Version 1.61.0 (2022-05-19)
==========================
Language
--------
- [`const fn` signatures can now include generic trait bounds][93827]
- [`const fn` signatures can now use `impl Trait` in argument and return position][93827]
- [Function pointers can now be created, cast, and passed around in a `const fn`][93827]
- [Recursive calls can now set the value of a function's opaque `impl Trait` return type][94081]
Compiler
--------
- [Linking modifier syntax in `#[link]` attributes and on the command line, as well as the `whole-archive` modifier specifically, are now supported][93901]
- [The `char` type is now described as UTF-32 in debuginfo][89887]
- The [`#[target_feature]`][target_feature] attribute [can now be used with aarch64 features][90621]
- X86 [`#[target_feature = "adx"]` is now stable][93745]
Libraries
---------
- [`ManuallyDrop` is now documented to have the same layout as `T`][88375]
- [`#[ignore = "…"]` messages are printed when running tests][92714]
- [Consistently show absent stdio handles on Windows as NULL handles][93263]
- [Make `std::io::stdio::lock()` return `'static` handles.][93965] Previously, the creation of locked handles to stdin/stdout/stderr would borrow the handles being locked, which prevented writing `let out = std::io::stdout().lock();` because `out` would outlive the return value of `stdout()`. Such code now works, eliminating a common pitfall that affected many Rust users.
- [`Vec::from_raw_parts` is now less restrictive about its inputs][95016]
- [`std::thread::available_parallelism` now takes cgroup quotas into account.][92697] Since `available_parallelism` is often used to create a thread pool for parallel computation, which may be CPU-bound for performance, `available_parallelism` will return a value consistent with the ability to use that many threads continuously, if possible. For instance, in a container with 8 virtual CPUs but quotas only allowing for 50% usage, `available_parallelism` will return 4.
Stabilized APIs
---------------
- [`Pin::static_mut`]
- [`Pin::static_ref`]
- [`Vec::retain_mut`]
- [`VecDeque::retain_mut`]
- [`Write` for `Cursor<[u8; N]>`][cursor-write-array]
- [`std::os::unix::net::SocketAddr::from_pathname`]
- [`std::process::ExitCode`] and [`std::process::Termination`]. The stabilization of these two APIs now makes it possible for programs to return errors from `main` with custom exit codes.
- [`std::thread::JoinHandle::is_finished`]
These APIs are now usable in const contexts:
- [`<*const T>::offset` and `<*mut T>::offset`][ptr-offset]
- [`<*const T>::wrapping_offset` and `<*mut T>::wrapping_offset`][ptr-wrapping_offset]
- [`<*const T>::add` and `<*mut T>::add`][ptr-add]
- [`<*const T>::sub` and `<*mut T>::sub`][ptr-sub]
- [`<*const T>::wrapping_add` and `<*mut T>::wrapping_add`][ptr-wrapping_add]
- [`<*const T>::wrapping_sub` and `<*mut T>::wrapping_sub`][ptr-wrapping_sub]
- [`<[T]>::as_mut_ptr`][slice-as_mut_ptr]
- [`<[T]>::as_ptr_range`][slice-as_ptr_range]
- [`<[T]>::as_mut_ptr_range`][slice-as_mut_ptr_range]
Cargo
-----
No feature changes, but see compatibility notes.
Compatibility Notes
-------------------
- Previously native static libraries were linked as `whole-archive` in some cases, but now rustc tries not to use `whole-archive` unless explicitly requested. This [change][93901] may result in linking errors in some cases. To fix such errors, native libraries linked from the command line, build scripts, or [`#[link]` attributes][link-attr] need to
- (more common) either be reordered to respect dependencies between them (if `a` depends on `b` then `a` should go first and `b` second)
- (less common) or be updated to use the [`+whole-archive`] modifier.
- [Catching a second unwind from FFI code while cleaning up from a Rust panic now causes the process to abort][92911]
- [Proc macros no longer see `ident` matchers wrapped in groups][92472]
- [The number of `#` in `r#` raw string literals is now required to be less than 256][95251]
- [When checking that a dyn type satisfies a trait bound, supertrait bounds are now enforced][92285]
- [`cargo vendor` now only accepts one value for each `--sync` flag][cargo/10448]
- [`cfg` predicates in `all()` and `any()` are always evaluated to detect errors, instead of short-circuiting.][94295] The compatibility considerations here arise in nightly-only code that used the short-circuiting behavior of `all` to write something like `cfg(all(feature = "nightly", syntax-requiring-nightly))`, which will now fail to compile. Instead, use either `cfg_attr(feature = "nightly", ...)` or nested uses of `cfg`.
- [bootstrap: static-libstdcpp is now enabled by default, and can now be disabled when llvm-tools is enabled][94832]
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.
- [debuginfo: Refactor debuginfo generation for types][94261]
- [Remove the everybody loops pass][93913]
[88375]: https://github.com/rust-lang/rust/pull/88375/
[89887]: https://github.com/rust-lang/rust/pull/89887/
[90621]: https://github.com/rust-lang/rust/pull/90621/
[92285]: https://github.com/rust-lang/rust/pull/92285/
[92472]: https://github.com/rust-lang/rust/pull/92472/
[92697]: https://github.com/rust-lang/rust/pull/92697/
[92714]: https://github.com/rust-lang/rust/pull/92714/
[92911]: https://github.com/rust-lang/rust/pull/92911/
[93263]: https://github.com/rust-lang/rust/pull/93263/
[93745]: https://github.com/rust-lang/rust/pull/93745/
[93827]: https://github.com/rust-lang/rust/pull/93827/
[93901]: https://github.com/rust-lang/rust/pull/93901/
[93913]: https://github.com/rust-lang/rust/pull/93913/
[93965]: https://github.com/rust-lang/rust/pull/93965/
[94081]: https://github.com/rust-lang/rust/pull/94081/
[94261]: https://github.com/rust-lang/rust/pull/94261/
[94295]: https://github.com/rust-lang/rust/pull/94295/
[94832]: https://github.com/rust-lang/rust/pull/94832/
[95016]: https://github.com/rust-lang/rust/pull/95016/
[95251]: https://github.com/rust-lang/rust/pull/95251/
[`+whole-archive`]: https://doc.rust-lang.org/stable/rustc/command-line-arguments.html#linking-modifiers-whole-archive
[`Pin::static_mut`]: https://doc.rust-lang.org/stable/std/pin/struct.Pin.html#method.static_mut
[`Pin::static_ref`]: https://doc.rust-lang.org/stable/std/pin/struct.Pin.html#method.static_ref
[`Vec::retain_mut`]: https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.retain_mut
[`VecDeque::retain_mut`]: https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.retain_mut
[`std::os::unix::net::SocketAddr::from_pathname`]: https://doc.rust-lang.org/stable/std/os/unix/net/struct.SocketAddr.html#method.from_pathname
[`std::process::ExitCode`]: https://doc.rust-lang.org/stable/std/process/struct.ExitCode.html
[`std::process::Termination`]: https://doc.rust-lang.org/stable/std/process/trait.Termination.html
[`std::thread::JoinHandle::is_finished`]: https://doc.rust-lang.org/stable/std/thread/struct.JoinHandle.html#method.is_finished
[cargo/10448]: https://github.com/rust-lang/cargo/pull/10448/
[cursor-write-array]: https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#impl-Write-4
[link-attr]: https://doc.rust-lang.org/stable/reference/items/external-blocks.html#the-link-attribute
[ptr-add]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.add
[ptr-offset]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.offset
[ptr-sub]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.sub
[ptr-wrapping_add]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.wrapping_add
[ptr-wrapping_offset]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.wrapping_offset
[ptr-wrapping_sub]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.wrapping_sub
[slice-as_mut_ptr]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_ptr
[slice-as_mut_ptr_range]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_mut_ptr_range
[slice-as_ptr_range]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.as_ptr_range
[target_feature]: https://doc.rust-lang.org/reference/attributes/codegen.html#the-target_feature-attribute
Version 1.60.0 (2022-04-07)
==========================
Language
--------
- [Stabilize `#[cfg(panic = "...")]` for either `"unwind"` or `"abort"`.][93658]
- [Stabilize `#[cfg(target_has_atomic = "...")]` for each integer size and `"ptr"`.][93824]
Compiler
--------
- [Enable combining `+crt-static` and `relocation-model=pic` on `x86_64-unknown-linux-gnu`][86374]
- [Fixes wrong `unreachable_pub` lints on nested and glob public reexport][87487]
- [Stabilize `-Z instrument-coverage` as `-C instrument-coverage`][90132]
- [Stabilize `-Z print-link-args` as `--print link-args`][91606]
- [Add new Tier 3 target `mips64-openwrt-linux-musl`\*][92300]
- [Add new Tier 3 target `armv7-unknown-linux-uclibceabi` (softfloat)\*][92383]
- [Fix invalid removal of newlines from doc comments][92357]
- [Add kernel target for RustyHermit][92670]
- [Deny mixing bin crate type with lib crate types][92933]
- [Make rustc use `RUST_BACKTRACE=full` by default][93566]
- [Upgrade to LLVM 14][93577]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [Guarantee call order for `sort_by_cached_key`][89621]
- [Improve `Duration::try_from_secs_f32`/`f64` accuracy by directly processing exponent and mantissa][90247]
- [Make `Instant::{duration_since, elapsed, sub}` saturating][89926]
- [Remove non-monotonic clocks workarounds in `Instant::now`][89926]
- [Make `BuildHasherDefault`, `iter::Empty` and `future::Pending` covariant][92630]
Stabilized APIs
---------------
- [`Arc::new_cyclic`][arc_new_cyclic]
- [`Rc::new_cyclic`][rc_new_cyclic]
- [`slice::EscapeAscii`][slice_escape_ascii]
- [`<[u8]>::escape_ascii`][slice_u8_escape_ascii]
- [`u8::escape_ascii`][u8_escape_ascii]
- [`Vec::spare_capacity_mut`][vec_spare_capacity_mut]
- [`MaybeUninit::assume_init_drop`][assume_init_drop]
- [`MaybeUninit::assume_init_read`][assume_init_read]
- [`i8::abs_diff`][i8_abs_diff]
- [`i16::abs_diff`][i16_abs_diff]
- [`i32::abs_diff`][i32_abs_diff]
- [`i64::abs_diff`][i64_abs_diff]
- [`i128::abs_diff`][i128_abs_diff]
- [`isize::abs_diff`][isize_abs_diff]
- [`u8::abs_diff`][u8_abs_diff]
- [`u16::abs_diff`][u16_abs_diff]
- [`u32::abs_diff`][u32_abs_diff]
- [`u64::abs_diff`][u64_abs_diff]
- [`u128::abs_diff`][u128_abs_diff]
- [`usize::abs_diff`][usize_abs_diff]
- [`Display for io::ErrorKind`][display_error_kind]
- [`From for ExitCode`][from_u8_exit_code]
- [`Not for !` (the "never" type)][not_never]
- [_Op_`Assign<$t> for Wrapping<$t>`][wrapping_assign_ops]
- [`arch::is_aarch64_feature_detected!`][is_aarch64_feature_detected]
Cargo
-----
- [Port cargo from `toml-rs` to `toml_edit`][cargo/10086]
- [Stabilize `-Ztimings` as `--timings`][cargo/10245]
- [Stabilize namespaced and weak dependency features.][cargo/10269]
- [Accept more `cargo:rustc-link-arg-*` types from build script output.][cargo/10274]
- [cargo-new should not add ignore rule on Cargo.lock inside subdirs][cargo/10379]
Misc
----
- [Ship docs on Tier 2 platforms by reusing the closest Tier 1 platform docs][92800]
- [Drop rustc-docs from complete profile][93742]
- [bootstrap: tidy up flag handling for llvm build][93918]
Compatibility Notes
-------------------
- [Remove compiler-rt linking hack on Android][83822]
- [Mitigations for platforms with non-monotonic clocks have been removed from
`Instant::now`][89926]. On platforms that don't provide monotonic clocks, an
instant is not guaranteed to be greater than an earlier instant anymore.
- [`Instant::{duration_since, elapsed, sub}` do not panic anymore on underflow,
saturating to `0` instead][89926]. In the real world the panic happened mostly
on platforms with buggy monotonic clock implementations rather than catching
programming errors like reversing the start and end times. Such programming
errors will now result in `0` rather than a panic.
- In a future release we're planning to increase the baseline requirements for
the Linux kernel to version 3.2, and for glibc to version 2.17. We'd love
your feedback in [PR #95026][95026].
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.
- [Switch all libraries to the 2021 edition][92068]
[83822]: https://github.com/rust-lang/rust/pull/83822
[86374]: https://github.com/rust-lang/rust/pull/86374
[87487]: https://github.com/rust-lang/rust/pull/87487
[89621]: https://github.com/rust-lang/rust/pull/89621
[89926]: https://github.com/rust-lang/rust/pull/89926
[90132]: https://github.com/rust-lang/rust/pull/90132
[90247]: https://github.com/rust-lang/rust/pull/90247
[91606]: https://github.com/rust-lang/rust/pull/91606
[92068]: https://github.com/rust-lang/rust/pull/92068
[92300]: https://github.com/rust-lang/rust/pull/92300
[92357]: https://github.com/rust-lang/rust/pull/92357
[92383]: https://github.com/rust-lang/rust/pull/92383
[92630]: https://github.com/rust-lang/rust/pull/92630
[92670]: https://github.com/rust-lang/rust/pull/92670
[92800]: https://github.com/rust-lang/rust/pull/92800
[92933]: https://github.com/rust-lang/rust/pull/92933
[93566]: https://github.com/rust-lang/rust/pull/93566
[93577]: https://github.com/rust-lang/rust/pull/93577
[93658]: https://github.com/rust-lang/rust/pull/93658
[93742]: https://github.com/rust-lang/rust/pull/93742
[93824]: https://github.com/rust-lang/rust/pull/93824
[93918]: https://github.com/rust-lang/rust/pull/93918
[95026]: https://github.com/rust-lang/rust/pull/95026
[cargo/10086]: https://github.com/rust-lang/cargo/pull/10086
[cargo/10245]: https://github.com/rust-lang/cargo/pull/10245
[cargo/10269]: https://github.com/rust-lang/cargo/pull/10269
[cargo/10274]: https://github.com/rust-lang/cargo/pull/10274
[cargo/10379]: https://github.com/rust-lang/cargo/pull/10379
[arc_new_cyclic]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.new_cyclic
[rc_new_cyclic]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.new_cyclic
[slice_escape_ascii]: https://doc.rust-lang.org/stable/std/slice/struct.EscapeAscii.html
[slice_u8_escape_ascii]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.escape_ascii
[u8_escape_ascii]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.escape_ascii
[vec_spare_capacity_mut]: https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.spare_capacity_mut
[assume_init_drop]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_drop
[assume_init_read]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_read
[i8_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.abs_diff
[i16_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.abs_diff
[i32_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.abs_diff
[i64_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.abs_diff
[i128_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.abs_diff
[isize_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.abs_diff
[u8_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.abs_diff
[u16_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.abs_diff
[u32_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.abs_diff
[u64_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.abs_diff
[u128_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.abs_diff
[usize_abs_diff]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.abs_diff
[display_error_kind]: https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#impl-Display
[from_u8_exit_code]: https://doc.rust-lang.org/stable/std/process/struct.ExitCode.html#impl-From%3Cu8%3E
[not_never]: https://doc.rust-lang.org/stable/std/primitive.never.html#impl-Not
[wrapping_assign_ops]: https://doc.rust-lang.org/stable/std/num/struct.Wrapping.html#trait-implementations
[is_aarch64_feature_detected]: https://doc.rust-lang.org/stable/std/arch/macro.is_aarch64_feature_detected.html
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 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 (2022-01-20)
===========================
* 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`][87467]
- [Make RSplit: Clone not require T: Clone][90117]
- [Implement `Termination` for `Result`][88601]. This allows writing `fn main() -> Result`, 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, Extend)`][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 nonexistent.][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 nonexistent 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` 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 environment 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.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 ` 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` intrinsics 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`, but this may change in a
future edition to change `Item` to `T`. Calling `IntoIterator::into_iter`
directly on arrays will provide `impl Iterator` 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, Bound)`.][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
[83387]: https://github.com/rust-lang/rust/pull/83387
[82873]: https://github.com/rust-lang/rust/pull/82873
[82864]: https://github.com/rust-lang/rust/pull/82864
[82608]: https://github.com/rust-lang/rust/pull/82608
[82565]: https://github.com/rust-lang/rust/pull/82565
[80525]: https://github.com/rust-lang/rust/pull/80525
[79278]: https://github.com/rust-lang/rust/pull/79278
[78618]: https://github.com/rust-lang/rust/pull/78618
[77704]: https://github.com/rust-lang/rust/pull/77704
[83941]: https://github.com/rust-lang/rust/pull/83941
[83065]: https://github.com/rust-lang/rust/pull/83065
[81764]: https://github.com/rust-lang/rust/pull/81764
[81469]: https://github.com/rust-lang/rust/pull/81469
[cargo/9298]: https://github.com/rust-lang/cargo/pull/9298
[cargo/9282]: https://github.com/rust-lang/cargo/pull/9282
[cargo/9392]: https://github.com/rust-lang/cargo/pull/9392
[`AtomicBool::fetch_update`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicBool.html#method.fetch_update
[`AtomicPtr::fetch_update`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicPtr.html#method.fetch_update
[`BTreeMap::retain`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.retain
[`BTreeSet::retain`]: https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.retain
[`BufReader::seek_relative`]: https://doc.rust-lang.org/std/io/struct.BufReader.html#method.seek_relative
[`DebugStruct::non_exhaustive`]: https://doc.rust-lang.org/std/fmt/struct.DebugStruct.html#method.finish_non_exhaustive
[`Duration::MAX`]: https://doc.rust-lang.org/std/time/struct.Duration.html#associatedconstant.MAX
[`Duration::ZERO`]: https://doc.rust-lang.org/std/time/struct.Duration.html#associatedconstant.ZERO
[`Duration::is_zero`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.is_zero
[`Duration::saturating_add`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.saturating_add
[`Duration::saturating_mul`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.saturating_mul
[`Duration::saturating_sub`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.saturating_sub
[`ErrorKind::Unsupported`]: https://doc.rust-lang.org/std/io/enum.ErrorKind.html#variant.Unsupported
[`Option::insert`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.insert
[`Ordering::is_eq`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.is_eq
[`Ordering::is_ge`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.is_ge
[`Ordering::is_gt`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.is_gt
[`Ordering::is_le`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.is_le
[`Ordering::is_lt`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.is_lt
[`Ordering::is_ne`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.is_ne
[`OsStr::is_ascii`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.is_ascii
[`OsStr::make_ascii_lowercase`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.make_ascii_lowercase
[`OsStr::make_ascii_uppercase`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.make_ascii_uppercase
[`OsStr::to_ascii_lowercase`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.to_ascii_lowercase
[`OsStr::to_ascii_uppercase`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.to_ascii_uppercase
[`Peekable::peek_mut`]: https://doc.rust-lang.org/std/iter/struct.Peekable.html#method.peek_mut
[`Rc::decrement_strong_count`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.decrement_strong_count
[`Rc::increment_strong_count`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.increment_strong_count
[`Vec::extend_from_within`]: https://doc.rust-lang.org/beta/std/vec/struct.Vec.html#method.extend_from_within
[`array::from_mut`]: https://doc.rust-lang.org/beta/std/array/fn.from_mut.html
[`array::from_ref`]: https://doc.rust-lang.org/beta/std/array/fn.from_ref.html
[`cmp::max_by_key`]: https://doc.rust-lang.org/beta/std/cmp/fn.max_by_key.html
[`cmp::max_by`]: https://doc.rust-lang.org/beta/std/cmp/fn.max_by.html
[`cmp::min_by_key`]: https://doc.rust-lang.org/beta/std/cmp/fn.min_by_key.html
[`cmp::min_by`]: https://doc.rust-lang.org/beta/std/cmp/fn.min_by.html
[`f32::is_subnormal`]: https://doc.rust-lang.org/std/primitive.f32.html#method.is_subnormal
[`f64::is_subnormal`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_subnormal
[ietf6943]: https://datatracker.ietf.org/doc/html/rfc6943#section-3.1.1
Version 1.52.1 (2021-05-10)
============================
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 the widespread, and frequently occurring, breakage encountered by
Rust users due to newly enabled incremental verification in 1.52.0. Notably,
Rust users **should** upgrade to 1.52.0 or 1.52.1: the bugs that are detected by
newly added incremental verification are still present in past stable versions,
and are not yet fixed on any channel. These bugs can lead to miscompilation of
Rust binaries.
These problems only affect incremental builds, so release builds with Cargo
should not be affected unless the user has explicitly opted into incremental.
Debug and check builds are affected.
See [84970] for more details.
[84970]: https://github.com/rust-lang/rust/issues/84970
Version 1.52.0 (2021-05-06)
============================
Language
--------
- [Added the `unsafe_op_in_unsafe_fn` lint, which checks whether the unsafe code
in an `unsafe fn` is wrapped in a `unsafe` block.][79208] This lint
is allowed by default, and may become a warning or hard error in a
future edition.
- [You can now cast mutable references to arrays to a pointer of the same type as
the element.][81479]
Compiler
--------
- [Upgraded the default LLVM to LLVM 12.][81451]
Added tier 3\* support for the following targets.
- [`s390x-unknown-linux-musl`][82166]
- [`riscv32gc-unknown-linux-musl` & `riscv64gc-unknown-linux-musl`][82202]
- [`powerpc-unknown-openbsd`][82733]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`OsString` now implements `Extend` and `FromIterator`.][82121]
- [`cmp::Reverse` now has `#[repr(transparent)]` representation.][81879]
- [`Arc` now implements `error::Error`.][80553]
- [All integer division and remainder operations are now `const`.][80962]
Stabilised APIs
-------------
- [`Arguments::as_str`]
- [`char::MAX`]
- [`char::REPLACEMENT_CHARACTER`]
- [`char::UNICODE_VERSION`]
- [`char::decode_utf16`]
- [`char::from_digit`]
- [`char::from_u32_unchecked`]
- [`char::from_u32`]
- [`slice::partition_point`]
- [`str::rsplit_once`]
- [`str::split_once`]
The following previously stable APIs are now `const`.
- [`char::len_utf8`]
- [`char::len_utf16`]
- [`char::to_ascii_uppercase`]
- [`char::to_ascii_lowercase`]
- [`char::eq_ignore_ascii_case`]
- [`u8::to_ascii_uppercase`]
- [`u8::to_ascii_lowercase`]
- [`u8::eq_ignore_ascii_case`]
Rustdoc
-------
- [Rustdoc lints are now treated as a tool lint, meaning that
lints are now prefixed with `rustdoc::` (e.g. `#[warn(rustdoc::broken_intra_doc_links)]`).][80527]
Using the old style is still allowed, and will become a warning in
a future release.
- [Rustdoc now supports argument files.][82261]
- [Rustdoc now generates smart punctuation for documentation.][79423]
- [You can now use "task lists" in Rustdoc Markdown.][81766] E.g.
```markdown
- [x] Complete
- [ ] Todo
```
Misc
----
- [You can now pass multiple filters to tests.][81356] E.g.
`cargo test -- foo bar` will run all tests that match `foo` and `bar`.
- [Rustup now distributes PDB symbols for the `std` library on Windows,
allowing you to see `std` symbols when debugging.][82218]
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.
- [Check the result cache before the DepGraph when ensuring queries][81855]
- [Try fast_reject::simplify_type in coherence before doing full check][81744]
- [Only store a LocalDefId in some HIR nodes][81611]
- [Store HIR attributes in a side table][79519]
Compatibility Notes
-------------------
- [Cargo build scripts are now forbidden from setting `RUSTC_BOOTSTRAP`.][cargo/9181]
- [Removed support for the `x86_64-rumprun-netbsd` target.][82594]
- [Deprecated the `x86_64-sun-solaris` target in favor of `x86_64-pc-solaris`.][82216]
- [Rustdoc now only accepts `,`, ` `, and `\t` as delimiters for specifying
languages in code blocks.][78429]
- [Rustc now catches more cases of `pub_use_of_private_extern_crate`][80763]
- [Changes in how proc macros handle whitespace may lead to panics when used
with older `proc-macro-hack` versions. A `cargo update` should be sufficient to fix this in all cases.][84136]
- [Turn `#[derive]` into a regular macro attribute][79078]
[84136]: https://github.com/rust-lang/rust/issues/84136
[80763]: https://github.com/rust-lang/rust/pull/80763
[82166]: https://github.com/rust-lang/rust/pull/82166
[82121]: https://github.com/rust-lang/rust/pull/82121
[81879]: https://github.com/rust-lang/rust/pull/81879
[82261]: https://github.com/rust-lang/rust/pull/82261
[82218]: https://github.com/rust-lang/rust/pull/82218
[82216]: https://github.com/rust-lang/rust/pull/82216
[82202]: https://github.com/rust-lang/rust/pull/82202
[81855]: https://github.com/rust-lang/rust/pull/81855
[81766]: https://github.com/rust-lang/rust/pull/81766
[81744]: https://github.com/rust-lang/rust/pull/81744
[81611]: https://github.com/rust-lang/rust/pull/81611
[81479]: https://github.com/rust-lang/rust/pull/81479
[81451]: https://github.com/rust-lang/rust/pull/81451
[81356]: https://github.com/rust-lang/rust/pull/81356
[80962]: https://github.com/rust-lang/rust/pull/80962
[80553]: https://github.com/rust-lang/rust/pull/80553
[80527]: https://github.com/rust-lang/rust/pull/80527
[79519]: https://github.com/rust-lang/rust/pull/79519
[79423]: https://github.com/rust-lang/rust/pull/79423
[79208]: https://github.com/rust-lang/rust/pull/79208
[78429]: https://github.com/rust-lang/rust/pull/78429
[82733]: https://github.com/rust-lang/rust/pull/82733
[82594]: https://github.com/rust-lang/rust/pull/82594
[79078]: https://github.com/rust-lang/rust/pull/79078
[cargo/9181]: https://github.com/rust-lang/cargo/pull/9181
[`char::MAX`]: https://doc.rust-lang.org/std/primitive.char.html#associatedconstant.MAX
[`char::REPLACEMENT_CHARACTER`]: https://doc.rust-lang.org/std/primitive.char.html#associatedconstant.REPLACEMENT_CHARACTER
[`char::UNICODE_VERSION`]: https://doc.rust-lang.org/std/primitive.char.html#associatedconstant.UNICODE_VERSION
[`char::decode_utf16`]: https://doc.rust-lang.org/std/primitive.char.html#method.decode_utf16
[`char::from_u32`]: https://doc.rust-lang.org/std/primitive.char.html#method.from_u32
[`char::from_u32_unchecked`]: https://doc.rust-lang.org/std/primitive.char.html#method.from_u32_unchecked
[`char::from_digit`]: https://doc.rust-lang.org/std/primitive.char.html#method.from_digit
[`Peekable::next_if`]: https://doc.rust-lang.org/stable/std/iter/struct.Peekable.html#method.next_if
[`Peekable::next_if_eq`]: https://doc.rust-lang.org/stable/std/iter/struct.Peekable.html#method.next_if_eq
[`Arguments::as_str`]: https://doc.rust-lang.org/stable/std/fmt/struct.Arguments.html#method.as_str
[`str::split_once`]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_once
[`str::rsplit_once`]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.rsplit_once
[`slice::partition_point`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.partition_point
[`char::len_utf8`]: https://doc.rust-lang.org/stable/std/primitive.char.html#method.len_utf8
[`char::len_utf16`]: https://doc.rust-lang.org/stable/std/primitive.char.html#method.len_utf16
[`char::to_ascii_uppercase`]: https://doc.rust-lang.org/stable/std/primitive.char.html#method.to_ascii_uppercase
[`char::to_ascii_lowercase`]: https://doc.rust-lang.org/stable/std/primitive.char.html#method.to_ascii_lowercase
[`char::eq_ignore_ascii_case`]: https://doc.rust-lang.org/stable/std/primitive.char.html#method.eq_ignore_ascii_case
[`u8::to_ascii_uppercase`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_ascii_uppercase
[`u8::to_ascii_lowercase`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_ascii_lowercase
[`u8::eq_ignore_ascii_case`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.eq_ignore_ascii_case
Version 1.51.0 (2021-03-25)
============================
Language
--------
- [You can now parameterize items such as functions, traits, and `struct`s by constant
values in addition to by types and lifetimes.][79135] Also known as "const generics"
E.g. you can now write the following. Note: Only values of primitive integers,
`bool`, or `char` types are currently permitted.
```rust
struct GenericArray {
inner: [T; LENGTH]
}
impl GenericArray {
const fn last(&self) -> Option<&T> {
if LENGTH == 0 {
None
} else {
Some(&self.inner[LENGTH - 1])
}
}
}
```
Compiler
--------
- [Added the `-Csplit-debuginfo` codegen option for macOS platforms.][79570]
This option controls whether debug information is split across multiple files
or packed into a single file. **Note** This option is unstable on other platforms.
- [Added tier 3\* support for `aarch64_be-unknown-linux-gnu`,
`aarch64-unknown-linux-gnu_ilp32`, and `aarch64_be-unknown-linux-gnu_ilp32` targets.][81455]
- [Added tier 3 support for `i386-unknown-linux-gnu` and `i486-unknown-linux-gnu` targets.][80662]
- [The `target-cpu=native` option will now detect individual features of CPUs.][80749]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`Box::downcast` is now also implemented for any `dyn Any + Send + Sync` object.][80945]
- [`str` now implements `AsMut`.][80279]
- [`u64` and `u128` now implement `From`.][79502]
- [`Error` is now implemented for `&T` where `T` implements `Error`.][75180]
- [`Poll::{map_ok, map_err}` are now implemented for `Poll>>`.][80968]
- [`unsigned_abs` is now implemented for all signed integer types.][80959]
- [`io::Empty` now implements `io::Seek`.][78044]
- [`rc::Weak` and `sync::Weak`'s methods such as `as_ptr` are now implemented for
`T: ?Sized` types.][80764]
- [`Div` and `Rem` by their `NonZero` variant is now implemented for all unsigned integers.][79134]
Stabilized APIs
---------------
- [`Arc::decrement_strong_count`]
- [`Arc::increment_strong_count`]
- [`Once::call_once_force`]
- [`Peekable::next_if_eq`]
- [`Peekable::next_if`]
- [`Seek::stream_position`]
- [`array::IntoIter`]
- [`panic::panic_any`]
- [`ptr::addr_of!`]
- [`ptr::addr_of_mut!`]
- [`slice::fill_with`]
- [`slice::split_inclusive_mut`]
- [`slice::split_inclusive`]
- [`slice::strip_prefix`]
- [`slice::strip_suffix`]
- [`str::split_inclusive`]
- [`sync::OnceState`]
- [`task::Wake`]
- [`VecDeque::range`]
- [`VecDeque::range_mut`]
Cargo
-----
- [Added the `split-debuginfo` profile option to control the -Csplit-debuginfo
codegen option.][cargo/9112]
- [Added the `resolver` field to `Cargo.toml` to enable the new feature resolver
and CLI option behavior.][cargo/8997] Version 2 of the feature resolver will try
to avoid unifying features of dependencies where that unification could be unwanted.
Such as using the same dependency with a `std` feature in a build scripts and
proc-macros, while using the `no-std` feature in the final binary. See the
[Cargo book documentation][feature-resolver@2.0] for more information on the feature.
Rustdoc
-------
- [Rustdoc will now include documentation for methods available from _nested_ `Deref` traits.][80653]
- [You can now provide a `--default-theme` flag which sets the default theme to use for
documentation.][79642]
Various improvements to intra-doc links:
- [You can link to non-path primitives such as `slice`.][80181]
- [You can link to associated items.][74489]
- [You can now include generic parameters when linking to items, like `Vec`.][76934]
Misc
----
- [You can now pass `--include-ignored` to tests (e.g. with
`cargo test -- --include-ignored`) to include testing tests marked `#[ignore]`.][80053]
Compatibility Notes
-------------------
- [WASI platforms no longer use the `wasm-bindgen` ABI, and instead use the wasm32 ABI.][79998]
- [`rustc` no longer promotes division, modulo and indexing operations to `const` that
could fail.][80579]
- [The minimum version of glibc for the following platforms has been bumped to version 2.31
for the distributed artifacts.][81521]
- `armv5te-unknown-linux-gnueabi`
- `sparc64-unknown-linux-gnu`
- `thumbv7neon-unknown-linux-gnueabihf`
- `armv7-unknown-linux-gnueabi`
- `x86_64-unknown-linux-gnux32`
- [`atomic::spin_loop_hint` has been deprecated.][80966] It's recommended to use `hint::spin_loop` instead.
Internal Only
-------------
- [Consistently avoid constructing optimized MIR when not doing codegen][80718]
[79135]: https://github.com/rust-lang/rust/pull/79135
[74489]: https://github.com/rust-lang/rust/pull/74489
[76934]: https://github.com/rust-lang/rust/pull/76934
[79570]: https://github.com/rust-lang/rust/pull/79570
[80181]: https://github.com/rust-lang/rust/pull/80181
[79642]: https://github.com/rust-lang/rust/pull/79642
[80945]: https://github.com/rust-lang/rust/pull/80945
[80279]: https://github.com/rust-lang/rust/pull/80279
[80053]: https://github.com/rust-lang/rust/pull/80053
[79502]: https://github.com/rust-lang/rust/pull/79502
[75180]: https://github.com/rust-lang/rust/pull/75180
[81521]: https://github.com/rust-lang/rust/pull/81521
[80968]: https://github.com/rust-lang/rust/pull/80968
[80959]: https://github.com/rust-lang/rust/pull/80959
[80718]: https://github.com/rust-lang/rust/pull/80718
[80653]: https://github.com/rust-lang/rust/pull/80653
[80579]: https://github.com/rust-lang/rust/pull/80579
[79998]: https://github.com/rust-lang/rust/pull/79998
[78044]: https://github.com/rust-lang/rust/pull/78044
[81455]: https://github.com/rust-lang/rust/pull/81455
[80764]: https://github.com/rust-lang/rust/pull/80764
[80749]: https://github.com/rust-lang/rust/pull/80749
[80662]: https://github.com/rust-lang/rust/pull/80662
[79134]: https://github.com/rust-lang/rust/pull/79134
[80966]: https://github.com/rust-lang/rust/pull/80966
[cargo/8997]: https://github.com/rust-lang/cargo/pull/8997
[cargo/9112]: https://github.com/rust-lang/cargo/pull/9112
[feature-resolver@2.0]: https://doc.rust-lang.org/nightly/cargo/reference/features.html#feature-resolver-version-2
[`Once::call_once_force`]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.call_once_force
[`sync::OnceState`]: https://doc.rust-lang.org/stable/std/sync/struct.OnceState.html
[`panic::panic_any`]: https://doc.rust-lang.org/stable/std/panic/fn.panic_any.html
[`slice::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix
[`slice::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_suffix
[`Arc::increment_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.increment_strong_count
[`Arc::decrement_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.decrement_strong_count
[`slice::fill_with`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.fill_with
[`ptr::addr_of!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of.html
[`ptr::addr_of_mut!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of_mut.html
[`array::IntoIter`]: https://doc.rust-lang.org/nightly/std/array/struct.IntoIter.html
[`slice::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive
[`slice::split_inclusive_mut`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive_mut
[`str::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_inclusive
[`task::Wake`]: https://doc.rust-lang.org/nightly/std/task/trait.Wake.html
[`Seek::stream_position`]: https://doc.rust-lang.org/nightly/std/io/trait.Seek.html#method.stream_position
[`Peekable::next_if`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if
[`Peekable::next_if_eq`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if_eq
[`VecDeque::range`]: https://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.range
[`VecDeque::range_mut`]: https://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.range_mut
Version 1.50.0 (2021-02-11)
============================
Language
-----------------------
- [You can now use `const` values for `x` in `[x; N]` array expressions.][79270]
This has been technically possible since 1.38.0, as it was unintentionally stabilized.
- [Assignments to `ManuallyDrop` union fields are now considered safe.][78068]
Compiler
-----------------------
- [Added tier 3\* support for the `armv5te-unknown-linux-uclibceabi` target.][78142]
- [Added tier 3 support for the `aarch64-apple-ios-macabi` target.][77484]
- [The `x86_64-unknown-freebsd` is now built with the full toolset.][79484]
- [Dropped support for all cloudabi targets.][78439]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
-----------------------
- [`proc_macro::Punct` now implements `PartialEq`.][78636]
- [`ops::{Index, IndexMut}` are now implemented for fixed sized arrays of any length.][74989]
- [On Unix platforms, the `std::fs::File` type now has a "niche" of `-1`.][74699]
This value cannot be a valid file descriptor, and now means `Option` takes
up the same amount of space as `File`.
Stabilized APIs
---------------
- [`bool::then`]
- [`btree_map::Entry::or_insert_with_key`]
- [`f32::clamp`]
- [`f64::clamp`]
- [`hash_map::Entry::or_insert_with_key`]
- [`Ord::clamp`]
- [`RefCell::take`]
- [`slice::fill`]
- [`UnsafeCell::get_mut`]
The following previously stable methods are now `const`.
- [`IpAddr::is_ipv4`]
- [`IpAddr::is_ipv6`]
- [`IpAddr::is_unspecified`]
- [`IpAddr::is_loopback`]
- [`IpAddr::is_multicast`]
- [`Ipv4Addr::octets`]
- [`Ipv4Addr::is_loopback`]
- [`Ipv4Addr::is_private`]
- [`Ipv4Addr::is_link_local`]
- [`Ipv4Addr::is_multicast`]
- [`Ipv4Addr::is_broadcast`]
- [`Ipv4Addr::is_documentation`]
- [`Ipv4Addr::to_ipv6_compatible`]
- [`Ipv4Addr::to_ipv6_mapped`]
- [`Ipv6Addr::segments`]
- [`Ipv6Addr::is_unspecified`]
- [`Ipv6Addr::is_loopback`]
- [`Ipv6Addr::is_multicast`]
- [`Ipv6Addr::to_ipv4`]
- [`Layout::size`]
- [`Layout::align`]
- [`Layout::from_size_align`]
- `pow` for all integer types.
- `checked_pow` for all integer types.
- `saturating_pow` for all integer types.
- `wrapping_pow` for all integer types.
- `next_power_of_two` for all unsigned integer types.
- `checked_next_power_of_two` for all unsigned integer types.
Cargo
-----------------------
- [Added the `[build.rustc-workspace-wrapper]` option.][cargo/8976]
This option sets a wrapper to execute instead of `rustc`, for workspace members only.
- [`cargo:rerun-if-changed` will now, if provided a directory, scan the entire
contents of that directory for changes.][cargo/8973]
- [Added the `--workspace` flag to the `cargo update` command.][cargo/8725]
Misc
----
- [The search results tab and the help button are focusable with keyboard in rustdoc.][79896]
- [Running tests will now print the total time taken to execute.][75752]
Compatibility Notes
-------------------
- [The `compare_and_swap` method on atomics has been deprecated.][79261] It's
recommended to use the `compare_exchange` and `compare_exchange_weak` methods instead.
- [Changes in how `TokenStream`s are checked have fixed some cases where you could write
unhygenic `macro_rules!` macros.][79472]
- [`#![test]` as an inner attribute is now considered unstable like other inner macro
attributes, and reports an error by default through the `soft_unstable` lint.][79003]
- [Overriding a `forbid` lint at the same level that it was set is now a hard error.][78864]
- [You can no longer intercept `panic!` calls by supplying your own macro.][78343] It's
recommended to use the `#[panic_handler]` attribute to provide your own implementation.
- [Semi-colons after item statements (e.g. `struct Foo {};`) now produce a warning.][78296]
[74989]: https://github.com/rust-lang/rust/pull/74989
[79261]: https://github.com/rust-lang/rust/pull/79261
[79896]: https://github.com/rust-lang/rust/pull/79896
[79484]: https://github.com/rust-lang/rust/pull/79484
[79472]: https://github.com/rust-lang/rust/pull/79472
[79270]: https://github.com/rust-lang/rust/pull/79270
[79003]: https://github.com/rust-lang/rust/pull/79003
[78864]: https://github.com/rust-lang/rust/pull/78864
[78636]: https://github.com/rust-lang/rust/pull/78636
[78439]: https://github.com/rust-lang/rust/pull/78439
[78343]: https://github.com/rust-lang/rust/pull/78343
[78296]: https://github.com/rust-lang/rust/pull/78296
[78068]: https://github.com/rust-lang/rust/pull/78068
[75752]: https://github.com/rust-lang/rust/pull/75752
[74699]: https://github.com/rust-lang/rust/pull/74699
[78142]: https://github.com/rust-lang/rust/pull/78142
[77484]: https://github.com/rust-lang/rust/pull/77484
[cargo/8976]: https://github.com/rust-lang/cargo/pull/8976
[cargo/8973]: https://github.com/rust-lang/cargo/pull/8973
[cargo/8725]: https://github.com/rust-lang/cargo/pull/8725
[`IpAddr::is_ipv4`]: https://doc.rust-lang.org/stable/std/net/enum.IpAddr.html#method.is_ipv4
[`IpAddr::is_ipv6`]: https://doc.rust-lang.org/stable/std/net/enum.IpAddr.html#method.is_ipv6
[`IpAddr::is_unspecified`]: https://doc.rust-lang.org/stable/std/net/enum.IpAddr.html#method.is_unspecified
[`IpAddr::is_loopback`]: https://doc.rust-lang.org/stable/std/net/enum.IpAddr.html#method.is_loopback
[`IpAddr::is_multicast`]: https://doc.rust-lang.org/stable/std/net/enum.IpAddr.html#method.is_multicast
[`Ipv4Addr::octets`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.octets
[`Ipv4Addr::is_loopback`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.is_loopback
[`Ipv4Addr::is_private`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.is_private
[`Ipv4Addr::is_link_local`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.is_link_local
[`Ipv4Addr::is_multicast`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.is_multicast
[`Ipv4Addr::is_broadcast`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.is_broadcast
[`Ipv4Addr::is_documentation`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.is_documentation
[`Ipv4Addr::to_ipv6_compatible`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.to_ipv6_compatible
[`Ipv4Addr::to_ipv6_mapped`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.to_ipv6_mapped
[`Ipv6Addr::segments`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.segments
[`Ipv6Addr::is_unspecified`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.is_unspecified
[`Ipv6Addr::is_loopback`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.is_loopback
[`Ipv6Addr::is_multicast`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.is_multicast
[`Ipv6Addr::to_ipv4`]: https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.to_ipv4
[`Layout::align`]: https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.align
[`Layout::from_size_align`]: https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.from_size_align
[`Layout::size`]: https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.size
[`Ord::clamp`]: https://doc.rust-lang.org/stable/std/cmp/trait.Ord.html#method.clamp
[`RefCell::take`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.take
[`UnsafeCell::get_mut`]: https://doc.rust-lang.org/stable/std/cell/struct.UnsafeCell.html#method.get_mut
[`bool::then`]: https://doc.rust-lang.org/stable/std/primitive.bool.html#method.then
[`btree_map::Entry::or_insert_with_key`]: https://doc.rust-lang.org/stable/std/collections/btree_map/enum.Entry.html#method.or_insert_with_key
[`f32::clamp`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.clamp
[`f64::clamp`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.clamp
[`hash_map::Entry::or_insert_with_key`]: https://doc.rust-lang.org/stable/std/collections/hash_map/enum.Entry.html#method.or_insert_with_key
[`slice::fill`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.fill
Version 1.49.0 (2020-12-31)
============================
Language
-----------------------
- [Unions can now implement `Drop`, and you can now have a field in a union
with `ManuallyDrop`.][77547]
- [You can now cast uninhabited enums to integers.][76199]
- [You can now bind by reference and by move in patterns.][76119] This
allows you to selectively borrow individual components of a type. E.g.
```rust
#[derive(Debug)]
struct Person {
name: String,
age: u8,
}
let person = Person {
name: String::from("Alice"),
age: 20,
};
// `name` is moved out of person, but `age` is referenced.
let Person { name, ref age } = person;
println!("{} {}", name, age);
```
Compiler
-----------------------
- [Added tier 1\* support for `aarch64-unknown-linux-gnu`.][78228]
- [Added tier 2 support for `aarch64-apple-darwin`.][75991]
- [Added tier 2 support for `aarch64-pc-windows-msvc`.][75914]
- [Added tier 3 support for `mipsel-unknown-none`.][78676]
- [Raised the minimum supported LLVM version to LLVM 9.][78848]
- [Output from threads spawned in tests is now captured.][78227]
- [Change os and vendor values to "none" and "unknown" for some targets][78951]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
-----------------------
- [`RangeInclusive` now checks for exhaustion when calling `contains` and indexing.][78109]
- [`ToString::to_string` now no longer shrinks the internal buffer in the default implementation.][77997]
Stabilized APIs
---------------
- [`slice::select_nth_unstable`]
- [`slice::select_nth_unstable_by`]
- [`slice::select_nth_unstable_by_key`]
The following previously stable methods are now `const`.
- [`Poll::is_ready`]
- [`Poll::is_pending`]
Cargo
-----------------------
- [Building a crate with `cargo-package` should now be independently reproducible.][cargo/8864]
- [`cargo-tree` now marks proc-macro crates.][cargo/8765]
- [Added `CARGO_PRIMARY_PACKAGE` build-time environment variable.][cargo/8758] This
variable will be set if the crate being built is one the user selected to build, either
with `-p` or through defaults.
- [You can now use glob patterns when specifying packages & targets.][cargo/8752]
Compatibility Notes
-------------------
- [Demoted `i686-unknown-freebsd` from host tier 2 to target tier 2 support.][78746]
- [Macros that end with a semi-colon are now treated as statements even if they expand to nothing.][78376]
- [Rustc will now check for the validity of some built-in attributes on enum variants.][77015]
Previously such invalid or unused attributes could be ignored.
- Leading whitespace is stripped more uniformly in documentation comments, which may change behavior. You
read [this post about the changes][rustdoc-ws-post] for more details.
- [Trait bounds are no longer inferred for associated types.][79904]
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.
- [rustc's internal crates are now compiled using the `initial-exec` Thread
Local Storage model.][78201]
- [Calculate visibilities once in resolve.][78077]
- [Added `system` to the `llvm-libunwind` bootstrap config option.][77703]
- [Added `--color` for configuring terminal color support to bootstrap.][79004]
[75991]: https://github.com/rust-lang/rust/pull/75991
[78951]: https://github.com/rust-lang/rust/pull/78951
[78848]: https://github.com/rust-lang/rust/pull/78848
[78746]: https://github.com/rust-lang/rust/pull/78746
[78376]: https://github.com/rust-lang/rust/pull/78376
[78228]: https://github.com/rust-lang/rust/pull/78228
[78227]: https://github.com/rust-lang/rust/pull/78227
[78201]: https://github.com/rust-lang/rust/pull/78201
[78109]: https://github.com/rust-lang/rust/pull/78109
[78077]: https://github.com/rust-lang/rust/pull/78077
[77997]: https://github.com/rust-lang/rust/pull/77997
[77703]: https://github.com/rust-lang/rust/pull/77703
[77547]: https://github.com/rust-lang/rust/pull/77547
[77015]: https://github.com/rust-lang/rust/pull/77015
[76199]: https://github.com/rust-lang/rust/pull/76199
[76119]: https://github.com/rust-lang/rust/pull/76119
[75914]: https://github.com/rust-lang/rust/pull/75914
[79004]: https://github.com/rust-lang/rust/pull/79004
[78676]: https://github.com/rust-lang/rust/pull/78676
[79904]: https://github.com/rust-lang/rust/issues/79904
[cargo/8864]: https://github.com/rust-lang/cargo/pull/8864
[cargo/8765]: https://github.com/rust-lang/cargo/pull/8765
[cargo/8758]: https://github.com/rust-lang/cargo/pull/8758
[cargo/8752]: https://github.com/rust-lang/cargo/pull/8752
[`slice::select_nth_unstable`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable
[`slice::select_nth_unstable_by`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable_by
[`slice::select_nth_unstable_by_key`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable_by_key
[`Poll::is_ready`]: https://doc.rust-lang.org/stable/std/task/enum.Poll.html#method.is_ready
[`Poll::is_pending`]: https://doc.rust-lang.org/stable/std/task/enum.Poll.html#method.is_pending
[rustdoc-ws-post]: https://blog.guillaume-gomez.fr/articles/2020-11-11+New+doc+comment+handling+in+rustdoc
Version 1.48.0 (2020-11-19)
==========================
Language
--------
- [The `unsafe` keyword is now syntactically permitted on modules.][75857] This
is still rejected *semantically*, but can now be parsed by procedural macros.
Compiler
--------
- [Stabilised the `-C link-self-contained=` compiler flag.][76158] This tells
`rustc` whether to link its own C runtime and libraries or to rely on a external
linker to find them. (Supported only on `windows-gnu`, `linux-musl`, and `wasi` platforms.)
- [You can now use `-C target-feature=+crt-static` on `linux-gnu` targets.][77386]
Note: If you're using cargo you must explicitly pass the `--target` flag.
- [Added tier 2\* support for `aarch64-unknown-linux-musl`.][76420]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`io::Write` is now implemented for `&ChildStdin` `&Sink`, `&Stdout`,
and `&Stderr`.][76275]
- [All arrays of any length now implement `TryFrom>`.][76310]
- [The `matches!` macro now supports having a trailing comma.][74880]
- [`Vec` now implements `PartialEq<[B]>` where `A: PartialEq`.][74194]
- [The `RefCell::{replace, replace_with, clone}` methods now all use `#[track_caller]`.][77055]
Stabilized APIs
---------------
- [`slice::as_ptr_range`]
- [`slice::as_mut_ptr_range`]
- [`VecDeque::make_contiguous`]
- [`future::pending`]
- [`future::ready`]
The following previously stable methods are now `const fn`'s:
- [`Option::is_some`]
- [`Option::is_none`]
- [`Option::as_ref`]
- [`Result::is_ok`]
- [`Result::is_err`]
- [`Result::as_ref`]
- [`Ordering::reverse`]
- [`Ordering::then`]
Cargo
-----
Rustdoc
-------
- [You can now link to items in `rustdoc` using the intra-doc link
syntax.][74430] E.g. ``/// Uses [`std::future`]`` will automatically generate
a link to `std::future`'s documentation. See ["Linking to items by
name"][intradoc-links] for more information.
- [You can now specify `#[doc(alias = "")]` on items to add search aliases
when searching through `rustdoc`'s UI.][75740]
Compatibility Notes
-------------------
- [Promotion of references to `'static` lifetime inside `const fn` now follows the
same rules as inside a `fn` body.][75502] In particular, `&foo()` will not be
promoted to `'static` lifetime any more inside `const fn`s.
- [Associated type bindings on trait objects are now verified to meet the bounds
declared on the trait when checking that they implement the trait.][27675]
- [When trait bounds on associated types or opaque types are ambiguous, the
compiler no longer makes an arbitrary choice on which bound to use.][54121]
- [Fixed recursive nonterminals not being expanded in macros during
pretty-print/reparse check.][77153] This may cause errors if your macro wasn't
correctly handling recursive nonterminal tokens.
- [`&mut` references to non zero-sized types are no longer promoted.][75585]
- [`rustc` will now warn if you use attributes like `#[link_name]` or `#[cold]`
in places where they have no effect.][73461]
- [Updated `_mm256_extract_epi8` and `_mm256_extract_epi16` signatures in
`arch::{x86, x86_64}` to return `i32` to match the vendor signatures.][73166]
- [`mem::uninitialized` will now panic if any inner types inside a struct or enum
disallow zero-initialization.][71274]
- [`#[target_feature]` will now error if used in a place where it has no effect.][78143]
- [Foreign exceptions are now caught by `catch_unwind` and will cause an abort.][70212]
Note: This behaviour is not guaranteed and is still considered undefined behaviour,
see the [`catch_unwind`] documentation for further information.
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.
- [Building `rustc` from source now uses `ninja` by default over `make`.][74922]
You can continue building with `make` by setting `ninja=false` in
your `bootstrap.toml`.
- [cg_llvm: `fewer_names` in `uncached_llvm_type`][76030]
- [Made `ensure_sufficient_stack()` non-generic][76680]
[78143]: https://github.com/rust-lang/rust/issues/78143
[76680]: https://github.com/rust-lang/rust/pull/76680/
[76030]: https://github.com/rust-lang/rust/pull/76030/
[70212]: https://github.com/rust-lang/rust/pull/70212/
[27675]: https://github.com/rust-lang/rust/issues/27675/
[54121]: https://github.com/rust-lang/rust/issues/54121/
[71274]: https://github.com/rust-lang/rust/pull/71274/
[77386]: https://github.com/rust-lang/rust/pull/77386/
[77153]: https://github.com/rust-lang/rust/pull/77153/
[77055]: https://github.com/rust-lang/rust/pull/77055/
[76275]: https://github.com/rust-lang/rust/pull/76275/
[76310]: https://github.com/rust-lang/rust/pull/76310/
[76420]: https://github.com/rust-lang/rust/pull/76420/
[76158]: https://github.com/rust-lang/rust/pull/76158/
[75857]: https://github.com/rust-lang/rust/pull/75857/
[75585]: https://github.com/rust-lang/rust/pull/75585/
[75740]: https://github.com/rust-lang/rust/pull/75740/
[75502]: https://github.com/rust-lang/rust/pull/75502/
[74880]: https://github.com/rust-lang/rust/pull/74880/
[74922]: https://github.com/rust-lang/rust/pull/74922/
[74430]: https://github.com/rust-lang/rust/pull/74430/
[74194]: https://github.com/rust-lang/rust/pull/74194/
[73461]: https://github.com/rust-lang/rust/pull/73461/
[73166]: https://github.com/rust-lang/rust/pull/73166/
[intradoc-links]: https://doc.rust-lang.org/rustdoc/linking-to-items-by-name.html
[`catch_unwind`]: https://doc.rust-lang.org/std/panic/fn.catch_unwind.html
[`Option::is_some`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some
[`Option::is_none`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_none
[`Option::as_ref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_ref
[`Result::is_ok`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_ok
[`Result::is_err`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_err
[`Result::as_ref`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.as_ref
[`Ordering::reverse`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.reverse
[`Ordering::then`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then
[`slice::as_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr_range
[`slice::as_mut_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_mut_ptr_range
[`VecDeque::make_contiguous`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.make_contiguous
[`future::pending`]: https://doc.rust-lang.org/std/future/fn.pending.html
[`future::ready`]: https://doc.rust-lang.org/std/future/fn.ready.html
Version 1.47.0 (2020-10-08)
==========================
Language
--------
- [Closures will now warn when not used.][74869]
Compiler
--------
- [Stabilized the `-C control-flow-guard` codegen option][73893], which enables
[Control Flow Guard][1.47.0-cfg] for Windows platforms, and is ignored on other
platforms.
- [Upgraded to LLVM 11.][73526]
- [Added tier 3\* support for the `thumbv4t-none-eabi` target.][74419]
- [Upgrade the FreeBSD toolchain to version 11.4][75204]
- [`RUST_BACKTRACE`'s output is now more compact.][75048]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`CStr` now implements `Index>`.][74021]
- [Traits in `std`/`core` are now implemented for arrays of any length, not just
those of length less than 33.][74060]
- [`ops::RangeFull` and `ops::Range` now implement Default.][73197]
- [`panic::Location` now implements `Copy`, `Clone`, `Eq`, `Hash`, `Ord`,
`PartialEq`, and `PartialOrd`.][73583]
Stabilized APIs
---------------
- [`Ident::new_raw`]
- [`Range::is_empty`]
- [`RangeInclusive::is_empty`]
- [`Result::as_deref`]
- [`Result::as_deref_mut`]
- [`Vec::leak`]
- [`pointer::offset_from`]
- [`f32::TAU`]
- [`f64::TAU`]
The following previously stable APIs have now been made const.
- [The `new` method for all `NonZero` integers.][73858]
- [The `checked_add`,`checked_sub`,`checked_mul`,`checked_neg`, `checked_shl`,
`checked_shr`, `saturating_add`, `saturating_sub`, and `saturating_mul`
methods for all integers.][73858]
- [The `checked_abs`, `saturating_abs`, `saturating_neg`, and `signum` for all
signed integers.][73858]
- [The `is_ascii_alphabetic`, `is_ascii_uppercase`, `is_ascii_lowercase`,
`is_ascii_alphanumeric`, `is_ascii_digit`, `is_ascii_hexdigit`,
`is_ascii_punctuation`, `is_ascii_graphic`, `is_ascii_whitespace`, and
`is_ascii_control` methods for `char` and `u8`.][73858]
Cargo
-----
- [`build-dependencies` are now built with opt-level 0 by default.][cargo/8500]
You can override this by setting the following in your `Cargo.toml`.
```toml
[profile.release.build-override]
opt-level = 3
```
- [`cargo-help` will now display man pages for commands rather just the
`--help` text.][cargo/8456]
- [`cargo-metadata` now emits a `test` field indicating if a target has
tests enabled.][cargo/8478]
- [`workspace.default-members` now respects `workspace.exclude`.][cargo/8485]
- [`cargo-publish` will now use an alternative registry by default if it's the
only registry specified in `package.publish`.][cargo/8571]
Misc
----
- [Added a help button beside Rustdoc's searchbar that explains rustdoc's
type based search.][75366]
- [Added the Ayu theme to rustdoc.][71237]
Compatibility Notes
-------------------
- [Bumped the minimum supported Emscripten version to 1.39.20.][75716]
- [Fixed a regression parsing `{} && false` in tail expressions.][74650]
- [Added changes to how proc-macros are expanded in `macro_rules!` that should
help to preserve more span information.][73084] These changes may cause
compilation errors if your macro was unhygenic or didn't correctly handle
`Delimiter::None`.
- [Moved support for the CloudABI target to tier 3.][75568]
- [`linux-gnu` targets now require minimum kernel 2.6.32 and glibc 2.11.][74163]
- [Added the `rustc-docs` component.][75560] This allows you to install
and read the documentation for the compiler internal APIs. (Currently only
available for `x86_64-unknown-linux-gnu`.)
Internal Only
--------
- [Improved default settings for bootstrapping in `x.py`.][73964] You can read details about this change in the ["Changes to `x.py` defaults"](https://blog.rust-lang.org/inside-rust/2020/08/30/changes-to-x-py-defaults.html) post on the Inside Rust blog.
[1.47.0-cfg]: https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard
[75048]: https://github.com/rust-lang/rust/pull/75048/
[74163]: https://github.com/rust-lang/rust/pull/74163/
[71237]: https://github.com/rust-lang/rust/pull/71237/
[74869]: https://github.com/rust-lang/rust/pull/74869/
[73858]: https://github.com/rust-lang/rust/pull/73858/
[75716]: https://github.com/rust-lang/rust/pull/75716/
[75560]: https://github.com/rust-lang/rust/pull/75560/
[75568]: https://github.com/rust-lang/rust/pull/75568/
[75366]: https://github.com/rust-lang/rust/pull/75366/
[75204]: https://github.com/rust-lang/rust/pull/75204/
[74650]: https://github.com/rust-lang/rust/pull/74650/
[74419]: https://github.com/rust-lang/rust/pull/74419/
[73964]: https://github.com/rust-lang/rust/pull/73964/
[74021]: https://github.com/rust-lang/rust/pull/74021/
[74060]: https://github.com/rust-lang/rust/pull/74060/
[73893]: https://github.com/rust-lang/rust/pull/73893/
[73526]: https://github.com/rust-lang/rust/pull/73526/
[73583]: https://github.com/rust-lang/rust/pull/73583/
[73084]: https://github.com/rust-lang/rust/pull/73084/
[73197]: https://github.com/rust-lang/rust/pull/73197/
[cargo/8456]: https://github.com/rust-lang/cargo/pull/8456/
[cargo/8478]: https://github.com/rust-lang/cargo/pull/8478/
[cargo/8485]: https://github.com/rust-lang/cargo/pull/8485/
[cargo/8500]: https://github.com/rust-lang/cargo/pull/8500/
[cargo/8571]: https://github.com/rust-lang/cargo/pull/8571/
[`Ident::new_raw`]: https://doc.rust-lang.org/nightly/proc_macro/struct.Ident.html#method.new_raw
[`Range::is_empty`]: https://doc.rust-lang.org/nightly/std/ops/struct.Range.html#method.is_empty
[`RangeInclusive::is_empty`]: https://doc.rust-lang.org/nightly/std/ops/struct.RangeInclusive.html#method.is_empty
[`Result::as_deref_mut`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#method.as_deref_mut
[`Result::as_deref`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#method.as_deref
[`Vec::leak`]: https://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.leak
[`f32::TAU`]: https://doc.rust-lang.org/nightly/std/f32/consts/constant.TAU.html
[`f64::TAU`]: https://doc.rust-lang.org/nightly/std/f64/consts/constant.TAU.html
[`pointer::offset_from`]: https://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.offset_from
Version 1.46.0 (2020-08-27)
==========================
Language
--------
- [`if`, `match`, and `loop` expressions can now be used in const functions.][72437]
- [Additionally you are now also able to coerce and cast to slices (`&[T]`) in
const functions.][73862]
- [The `#[track_caller]` attribute can now be added to functions to use the
function's caller's location information for panic messages.][72445]
- [Recursively indexing into tuples no longer needs parentheses.][71322] E.g.
`x.0.0` over `(x.0).0`.
- [`mem::transmute` can now be used in statics and constants.][72920] **Note**
You currently can't use `mem::transmute` in constant functions.
Compiler
--------
- [You can now use the `cdylib` target on Apple iOS and tvOS platforms.][73516]
- [Enabled static "Position Independent Executables" by default
for `x86_64-unknown-linux-musl`.][70740]
Libraries
---------
- [`mem::forget` is now a `const fn`.][73887]
- [`String` now implements `From`.][73466]
- [The `leading_ones`, and `trailing_ones` methods have been stabilised for all
integer types.][73032]
- [`vec::IntoIter` now implements `AsRef<[T]>`.][72583]
- [All non-zero integer types (`NonZeroU8`) now implement `TryFrom` for their
zero-able equivalent (e.g. `TryFrom`).][72717]
- [`&[T]` and `&mut [T]` now implement `PartialEq>`.][71660]
- [`(String, u16)` now implements `ToSocketAddrs`.][73007]
- [`vec::Drain<'_, T>` now implements `AsRef<[T]>`.][72584]
Stabilized APIs
---------------
- [`Option::zip`]
- [`vec::Drain::as_slice`]
Cargo
-----
Added a number of new environment variables that are now available when
compiling your crate.
- [`CARGO_BIN_NAME` and `CARGO_CRATE_NAME`][cargo/8270] Providing the name of
the specific binary being compiled and the name of the crate.
- [`CARGO_PKG_LICENSE`][cargo/8325] The license from the manifest of the package.
- [`CARGO_PKG_LICENSE_FILE`][cargo/8387] The path to the license file.
Compatibility Notes
-------------------
- [The target configuration option `abi_blacklist` has been renamed
to `unsupported_abis`.][74150] The old name will still continue to work.
- [Rustc will now warn if you cast a C-like enum that implements `Drop`.][72331]
This was previously accepted but will become a hard error in a future release.
- [Rustc will fail to compile if you have a struct with
`#[repr(i128)]` or `#[repr(u128)]`.][74109] This representation is currently only
allowed on `enum`s.
- [Tokens passed to `macro_rules!` are now always captured.][73293] This helps
ensure that spans have the correct information, and may cause breakage if you
were relying on receiving spans with dummy information.
- [The InnoSetup installer for Windows is no longer available.][72569] This was
a legacy installer that was replaced by a MSI installer a few years ago but
was still being built.
- [`{f32, f64}::asinh` now returns the correct values for negative numbers.][72486]
- [Rustc will no longer accept overlapping trait implementations that only
differ in how the lifetime was bound.][72493]
- [Rustc now correctly relates the lifetime of an existential associated
type.][71896] This fixes some edge cases where `rustc` would erroneously allow
you to pass a shorter lifetime than expected.
- [Rustc now dynamically links to `libz` (also called `zlib`) on Linux.][74420]
The library will need to be installed for `rustc` to work, even though we
expect it to be already available on most systems.
- [Tests annotated with `#[should_panic]` are broken on ARMv7 while running
under QEMU.][74820]
- [Pretty printing of some tokens in procedural macros changed.][75453] The
exact output returned by rustc's pretty printing is an unstable
implementation detail: we recommend any macro relying on it to switch to a
more robust parsing system.
[75453]: https://github.com/rust-lang/rust/issues/75453/
[74820]: https://github.com/rust-lang/rust/issues/74820/
[74420]: https://github.com/rust-lang/rust/issues/74420/
[74109]: https://github.com/rust-lang/rust/pull/74109/
[74150]: https://github.com/rust-lang/rust/pull/74150/
[73862]: https://github.com/rust-lang/rust/pull/73862/
[73887]: https://github.com/rust-lang/rust/pull/73887/
[73466]: https://github.com/rust-lang/rust/pull/73466/
[73516]: https://github.com/rust-lang/rust/pull/73516/
[73293]: https://github.com/rust-lang/rust/pull/73293/
[73007]: https://github.com/rust-lang/rust/pull/73007/
[73032]: https://github.com/rust-lang/rust/pull/73032/
[72920]: https://github.com/rust-lang/rust/pull/72920/
[72569]: https://github.com/rust-lang/rust/pull/72569/
[72583]: https://github.com/rust-lang/rust/pull/72583/
[72584]: https://github.com/rust-lang/rust/pull/72584/
[72717]: https://github.com/rust-lang/rust/pull/72717/
[72437]: https://github.com/rust-lang/rust/pull/72437/
[72445]: https://github.com/rust-lang/rust/pull/72445/
[72486]: https://github.com/rust-lang/rust/pull/72486/
[72493]: https://github.com/rust-lang/rust/pull/72493/
[72331]: https://github.com/rust-lang/rust/pull/72331/
[71896]: https://github.com/rust-lang/rust/pull/71896/
[71660]: https://github.com/rust-lang/rust/pull/71660/
[71322]: https://github.com/rust-lang/rust/pull/71322/
[70740]: https://github.com/rust-lang/rust/pull/70740/
[cargo/8270]: https://github.com/rust-lang/cargo/pull/8270/
[cargo/8325]: https://github.com/rust-lang/cargo/pull/8325/
[cargo/8387]: https://github.com/rust-lang/cargo/pull/8387/
[`Option::zip`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.zip
[`vec::Drain::as_slice`]: https://doc.rust-lang.org/stable/std/vec/struct.Drain.html#method.as_slice
Version 1.45.2 (2020-08-03)
==========================
* [Fix bindings in tuple struct patterns][74954]
* [Fix track_caller integration with trait objects][74784]
[74954]: https://github.com/rust-lang/rust/issues/74954
[74784]: https://github.com/rust-lang/rust/issues/74784
Version 1.45.1 (2020-07-30)
==========================
* [Fix const propagation with references.][73613]
* [rustfmt accepts rustfmt_skip in cfg_attr again.][73078]
* [Avoid spurious implicit region bound.][74509]
* [Install clippy on x.py install][74457]
[73613]: https://github.com/rust-lang/rust/pull/73613
[73078]: https://github.com/rust-lang/rust/issues/73078
[74509]: https://github.com/rust-lang/rust/pull/74509
[74457]: https://github.com/rust-lang/rust/pull/74457
Version 1.45.0 (2020-07-16)
==========================
Language
--------
- [Out of range float to int conversions using `as` has been defined as a saturating
conversion.][71269] This was previously undefined behaviour, but you can use the
`{f64, f32}::to_int_unchecked` methods to continue using the current behaviour, which
may be desirable in rare performance sensitive situations.
- [`mem::Discriminant` now uses `T`'s discriminant type instead of always
using `u64`.][70705]
- [Function like procedural macros can now be used in expression, pattern, and statement
positions.][68717] This means you can now use a function-like procedural macro
anywhere you can use a declarative (`macro_rules!`) macro.
Compiler
--------
- [You can now override individual target features through the `target-feature`
flag.][72094] E.g. `-C target-feature=+avx2 -C target-feature=+fma` is now
equivalent to `-C target-feature=+avx2,+fma`.
- [Added the `force-unwind-tables` flag.][69984] This option allows
rustc to always generate unwind tables regardless of panic strategy.
- [Added the `embed-bitcode` flag.][71716] This codegen flag allows rustc
to include LLVM bitcode into generated `rlib`s (this is on by default).
- [Added the `tiny` value to the `code-model` codegen flag.][72397]
- [Added tier 3 support\* for the `mipsel-sony-psp` target.][72062]
- [Added tier 3 support for the `thumbv7a-uwp-windows-msvc` target.][72133]
- [Upgraded to LLVM 10.][67759]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`net::{SocketAddr, SocketAddrV4, SocketAddrV6}` now implements `PartialOrd`
and `Ord`.][72239]
- [`proc_macro::TokenStream` now implements `Default`.][72234]
- [You can now use `char` with
`ops::{Range, RangeFrom, RangeFull, RangeInclusive, RangeTo}` to iterate over
a range of codepoints.][72413] E.g.
you can now write the following;
```rust
for ch in 'a'..='z' {
print!("{}", ch);
}
println!();
// Prints "abcdefghijklmnopqrstuvwxyz"
```
- [`OsString` now implements `FromStr`.][71662]
- [The `saturating_neg` method has been added to all signed integer primitive
types, and the `saturating_abs` method has been added for all integer
primitive types.][71886]
- [`Arc`, `Rc` now implement `From>`, and `Box` now
implements `From` when `T` is `[T: Copy]`, `str`, `CStr`, `OsStr`,
or `Path`.][71447]
- [`Box<[T]>` now implements `From<[T; N]>`.][71095]
- [`BitOr` and `BitOrAssign` are implemented for all `NonZero`
integer types.][69813]
- [The `fetch_min`, and `fetch_max` methods have been added to all atomic
integer types.][72324]
- [The `fetch_update` method has been added to all atomic integer types.][71843]
Stabilized APIs
---------------
- [`Arc::as_ptr`]
- [`BTreeMap::remove_entry`]
- [`Rc::as_ptr`]
- [`rc::Weak::as_ptr`]
- [`rc::Weak::from_raw`]
- [`rc::Weak::into_raw`]
- [`str::strip_prefix`]
- [`str::strip_suffix`]
- [`sync::Weak::as_ptr`]
- [`sync::Weak::from_raw`]
- [`sync::Weak::into_raw`]
- [`char::UNICODE_VERSION`]
- [`Span::resolved_at`]
- [`Span::located_at`]
- [`Span::mixed_site`]
- [`unix::process::CommandExt::arg0`]
Cargo
-----
- [Cargo uses the `embed-bitcode` flag to optimize disk usage and build
time.][cargo/8066]
Misc
----
- [Rustdoc now supports strikethrough text in Markdown.][71928] E.g.
`~~outdated information~~` becomes "~~outdated information~~".
- [Added an emoji to Rustdoc's deprecated API message.][72014]
Compatibility Notes
-------------------
- [Trying to self initialize a static value (that is creating a value using
itself) is unsound and now causes a compile error.][71140]
- [`{f32, f64}::powi` now returns a slightly different value on Windows.][73420]
This is due to changes in LLVM's intrinsics which `{f32, f64}::powi` uses.
- [Rustdoc's CLI's extra error exit codes have been removed.][71900] These were
previously undocumented and not intended for public use. Rustdoc still provides
a non-zero exit code on errors.
- [Rustc's `lto` flag is incompatible with the new `embed-bitcode=no`.][71848]
This may cause issues if LTO is enabled through `RUSTFLAGS` or `cargo rustc`
flags while cargo is adding `embed-bitcode` itself. The recommended way to
control LTO is with Cargo profiles, either in `Cargo.toml` or `.cargo/config`,
or by setting `CARGO_PROFILE__LTO` in the environment.
Internals Only
--------------
- [Make clippy a git subtree instead of a git submodule][70655]
- [Unify the undo log of all snapshot types][69464]
[71848]: https://github.com/rust-lang/rust/issues/71848/
[73420]: https://github.com/rust-lang/rust/issues/73420/
[72324]: https://github.com/rust-lang/rust/pull/72324/
[71843]: https://github.com/rust-lang/rust/pull/71843/
[71886]: https://github.com/rust-lang/rust/pull/71886/
[72234]: https://github.com/rust-lang/rust/pull/72234/
[72239]: https://github.com/rust-lang/rust/pull/72239/
[72397]: https://github.com/rust-lang/rust/pull/72397/
[72413]: https://github.com/rust-lang/rust/pull/72413/
[72014]: https://github.com/rust-lang/rust/pull/72014/
[72062]: https://github.com/rust-lang/rust/pull/72062/
[72094]: https://github.com/rust-lang/rust/pull/72094/
[72133]: https://github.com/rust-lang/rust/pull/72133/
[67759]: https://github.com/rust-lang/rust/pull/67759/
[71900]: https://github.com/rust-lang/rust/pull/71900/
[71928]: https://github.com/rust-lang/rust/pull/71928/
[71662]: https://github.com/rust-lang/rust/pull/71662/
[71716]: https://github.com/rust-lang/rust/pull/71716/
[71447]: https://github.com/rust-lang/rust/pull/71447/
[71269]: https://github.com/rust-lang/rust/pull/71269/
[71095]: https://github.com/rust-lang/rust/pull/71095/
[71140]: https://github.com/rust-lang/rust/pull/71140/
[70655]: https://github.com/rust-lang/rust/pull/70655/
[70705]: https://github.com/rust-lang/rust/pull/70705/
[69984]: https://github.com/rust-lang/rust/pull/69984/
[69813]: https://github.com/rust-lang/rust/pull/69813/
[69464]: https://github.com/rust-lang/rust/pull/69464/
[68717]: https://github.com/rust-lang/rust/pull/68717/
[cargo/8066]: https://github.com/rust-lang/cargo/pull/8066
[`Arc::as_ptr`]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.as_ptr
[`BTreeMap::remove_entry`]: https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.remove_entry
[`Rc::as_ptr`]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.as_ptr
[`rc::Weak::as_ptr`]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.as_ptr
[`rc::Weak::from_raw`]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.from_raw
[`rc::Weak::into_raw`]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.into_raw
[`sync::Weak::as_ptr`]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.as_ptr
[`sync::Weak::from_raw`]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.from_raw
[`sync::Weak::into_raw`]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.into_raw
[`str::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.strip_prefix
[`str::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.strip_suffix
[`char::UNICODE_VERSION`]: https://doc.rust-lang.org/stable/std/char/constant.UNICODE_VERSION.html
[`Span::resolved_at`]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.resolved_at
[`Span::located_at`]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.located_at
[`Span::mixed_site`]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.mixed_site
[`unix::process::CommandExt::arg0`]: https://doc.rust-lang.org/std/os/unix/process/trait.CommandExt.html#tymethod.arg0
Version 1.44.1 (2020-06-18)
===========================
* [rustfmt accepts rustfmt_skip in cfg_attr again.][73078]
* [Don't hash executable filenames on apple platforms, fixing backtraces.][cargo/8329]
* [Fix crashes when finding backtrace on macOS.][71397]
* [Clippy applies lint levels into different files.][clippy/5356]
[71397]: https://github.com/rust-lang/rust/issues/71397
[73078]: https://github.com/rust-lang/rust/issues/73078
[cargo/8329]: https://github.com/rust-lang/cargo/pull/8329
[clippy/5356]: https://github.com/rust-lang/rust-clippy/issues/5356
Version 1.44.0 (2020-06-04)
==========================
Language
--------
- [You can now use `async/.await` with `#[no_std]` enabled.][69033]
- [Added the `unused_braces` lint.][70081]
**Syntax-only changes**
- [Expansion-driven outline module parsing][69838]
```rust
#[cfg(FALSE)]
mod foo {
mod bar {
mod baz; // `foo/bar/baz.rs` doesn't exist, but no error!
}
}
```
These are still rejected semantically, so you will likely receive an error but
these changes can be seen and parsed by macros and conditional compilation.
Compiler
--------
- [Rustc now respects the `-C codegen-units` flag in incremental mode.][70156]
Additionally when in incremental mode rustc defaults to 256 codegen units.
- [Refactored `catch_unwind` to have zero-cost, unless unwinding is enabled and
a panic is thrown.][67502]
- [Added tier 3\* support for the `aarch64-unknown-none` and
`aarch64-unknown-none-softfloat` targets.][68334]
- [Added tier 3 support for `arm64-apple-tvos` and
`x86_64-apple-tvos` targets.][68191]
Libraries
---------
- [Special cased `vec![]` to map directly to `Vec::new()`.][70632] This allows
`vec![]` to be able to be used in `const` contexts.
- [`convert::Infallible` now implements `Hash`.][70281]
- [`OsString` now implements `DerefMut` and `IndexMut` returning
a `&mut OsStr`.][70048]
- [Unicode 13 is now supported.][69929]
- [`String` now implements `From<&mut str>`.][69661]
- [`IoSlice` now implements `Copy`.][69403]
- [`Vec` now implements `From<[T; N]>`.][68692] Where `N` is at most 32.
- [`proc_macro::LexError` now implements `fmt::Display` and `Error`.][68899]
- [`from_le_bytes`, `to_le_bytes`, `from_be_bytes`, `to_be_bytes`,
`from_ne_bytes`, and `to_ne_bytes` methods are now `const` for all
integer types.][69373]
Stabilized APIs
---------------
- [`PathBuf::with_capacity`]
- [`PathBuf::capacity`]
- [`PathBuf::clear`]
- [`PathBuf::reserve`]
- [`PathBuf::reserve_exact`]
- [`PathBuf::shrink_to_fit`]
- [`f32::to_int_unchecked`]
- [`f64::to_int_unchecked`]
- [`Layout::align_to`]
- [`Layout::pad_to_align`]
- [`Layout::array`]
- [`Layout::extend`]
Cargo
-----
- [Added the `cargo tree` command which will print a tree graph of
your dependencies.][cargo/8062] E.g.
```
mdbook v0.3.2 (/Users/src/rust/mdbook)
├── ammonia v3.0.0
│ ├── html5ever v0.24.0
│ │ ├── log v0.4.8
│ │ │ └── cfg-if v0.1.9
│ │ ├── mac v0.1.1
│ │ └── markup5ever v0.9.0
│ │ ├── log v0.4.8 (*)
│ │ ├── phf v0.7.24
│ │ │ └── phf_shared v0.7.24
│ │ │ ├── siphasher v0.2.3
│ │ │ └── unicase v1.4.2
│ │ │ [build-dependencies]
│ │ │ └── version_check v0.1.5
...
```
You can also display dependencies on multiple versions of the same crate with
`cargo tree -d` (short for `cargo tree --duplicates`).
Misc
----
- [Rustdoc now allows you to specify `--crate-version` to have rustdoc include
the version in the sidebar.][69494]
Compatibility Notes
-------------------
- [Rustc now correctly generates static libraries on Windows GNU targets with
the `.a` extension, rather than the previous `.lib`.][70937]
- [Removed the `-C no_integrated_as` flag from rustc.][70345]
- [The `file_name` property in JSON output of macro errors now points the actual
source file rather than the previous format of ``.][70969]
**Note:** this may not point to a file that actually exists on the user's system.
- [The minimum required external LLVM version has been bumped to LLVM 8.][71147]
- [`mem::{zeroed, uninitialised}` will now panic when used with types that do
not allow zero initialization such as `NonZeroU8`.][66059] This was
previously a warning.
- [In 1.45.0 (the next release) converting a `f64` to `u32` using the `as`
operator has been defined as a saturating operation.][71269] This was previously
undefined behaviour, but you can use the `{f64, f32}::to_int_unchecked` methods to
continue using the current behaviour, which may be desirable in rare performance
sensitive situations.
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.
- [dep_graph Avoid allocating a set on when the number reads are small.][69778]
- [Replace big JS dict with JSON parsing.][71250]
[69373]: https://github.com/rust-lang/rust/pull/69373/
[66059]: https://github.com/rust-lang/rust/pull/66059/
[68191]: https://github.com/rust-lang/rust/pull/68191/
[68899]: https://github.com/rust-lang/rust/pull/68899/
[71147]: https://github.com/rust-lang/rust/pull/71147/
[71250]: https://github.com/rust-lang/rust/pull/71250/
[70937]: https://github.com/rust-lang/rust/pull/70937/
[70969]: https://github.com/rust-lang/rust/pull/70969/
[70632]: https://github.com/rust-lang/rust/pull/70632/
[70281]: https://github.com/rust-lang/rust/pull/70281/
[70345]: https://github.com/rust-lang/rust/pull/70345/
[70048]: https://github.com/rust-lang/rust/pull/70048/
[70081]: https://github.com/rust-lang/rust/pull/70081/
[70156]: https://github.com/rust-lang/rust/pull/70156/
[71269]: https://github.com/rust-lang/rust/pull/71269/
[69838]: https://github.com/rust-lang/rust/pull/69838/
[69929]: https://github.com/rust-lang/rust/pull/69929/
[69661]: https://github.com/rust-lang/rust/pull/69661/
[69778]: https://github.com/rust-lang/rust/pull/69778/
[69494]: https://github.com/rust-lang/rust/pull/69494/
[69403]: https://github.com/rust-lang/rust/pull/69403/
[69033]: https://github.com/rust-lang/rust/pull/69033/
[68692]: https://github.com/rust-lang/rust/pull/68692/
[68334]: https://github.com/rust-lang/rust/pull/68334/
[67502]: https://github.com/rust-lang/rust/pull/67502/
[cargo/8062]: https://github.com/rust-lang/cargo/pull/8062/
[`PathBuf::with_capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.with_capacity
[`PathBuf::capacity`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.capacity
[`PathBuf::clear`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.clear
[`PathBuf::reserve`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve
[`PathBuf::reserve_exact`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.reserve_exact
[`PathBuf::shrink_to_fit`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.shrink_to_fit
[`f32::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_int_unchecked
[`f64::to_int_unchecked`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_int_unchecked
[`Layout::align_to`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.align_to
[`Layout::pad_to_align`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.pad_to_align
[`Layout::array`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.array
[`Layout::extend`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.extend
Version 1.43.1 (2020-05-07)
===========================
* [Updated openssl-src to 1.1.1g for CVE-2020-1967.][71430]
* [Fixed the stabilization of AVX-512 features.][71473]
* [Fixed `cargo package --list` not working with unpublished dependencies.][cargo/8151]
[71430]: https://github.com/rust-lang/rust/pull/71430
[71473]: https://github.com/rust-lang/rust/issues/71473
[cargo/8151]: https://github.com/rust-lang/cargo/issues/8151
Version 1.43.0 (2020-04-23)
==========================
Language
--------
- [Fixed using binary operations with `&{number}` (e.g. `&1.0`) not having
the type inferred correctly.][68129]
- [Attributes such as `#[cfg()]` can now be used on `if` expressions.][69201]
**Syntax only changes**
- [Allow `type Foo: Ord` syntactically.][69361]
- [Fuse associated and extern items up to defaultness.][69194]
- [Syntactically allow `self` in all `fn` contexts.][68764]
- [Merge `fn` syntax + cleanup item parsing.][68728]
- [`item` macro fragments can be interpolated into `trait`s, `impl`s, and `extern` blocks.][69366]
For example, you may now write:
```rust
macro_rules! mac_trait {
($i:item) => {
trait T { $i }
}
}
mac_trait! {
fn foo() {}
}
```
These are still rejected *semantically*, so you will likely receive an error but
these changes can be seen and parsed by macros and
conditional compilation.
Compiler
--------
- [You can now pass multiple lint flags to rustc to override the previous
flags.][67885] For example; `rustc -D unused -A unused-variables` denies
everything in the `unused` lint group except `unused-variables` which
is explicitly allowed. However, passing `rustc -A unused-variables -D unused` denies
everything in the `unused` lint group **including** `unused-variables` since
the allow flag is specified before the deny flag (and therefore overridden).
- [rustc will now prefer your system MinGW libraries over its bundled libraries
if they are available on `windows-gnu`.][67429]
- [rustc now buffers errors/warnings printed in JSON.][69227]
Libraries
---------
- [`Arc<[T; N]>`, `Box<[T; N]>`, and `Rc<[T; N]>`, now implement
`TryFrom>`,`TryFrom>`, and `TryFrom>`
respectively.][69538] **Note** These conversions are only available when `N`
is `0..=32`.
- [You can now use associated constants on floats and integers directly, rather
than having to import the module.][68952] e.g. You can now write `u32::MAX` or
`f32::NAN` with no imports.
- [`u8::is_ascii` is now `const`.][68984]
- [`String` now implements `AsMut`.][68742]
- [Added the `primitive` module to `std` and `core`.][67637] This module
reexports Rust's primitive types. This is mainly useful in macros
where you want avoid these types being shadowed.
- [Relaxed some of the trait bounds on `HashMap` and `HashSet`.][67642]
- [`string::FromUtf8Error` now implements `Clone + Eq`.][68738]
Stabilized APIs
---------------
- [`Once::is_completed`]
- [`f32::LOG10_2`]
- [`f32::LOG2_10`]
- [`f64::LOG10_2`]
- [`f64::LOG2_10`]
- [`iter::once_with`]
Cargo
-----
- [You can now set config `[profile]`s in your `.cargo/config`, or through
your environment.][cargo/7823]
- [Cargo will now set `CARGO_BIN_EXE_` pointing to a binary's
executable path when running integration tests or benchmarks.][cargo/7697]
`` is the name of your binary as-is e.g. If you wanted the executable
path for a binary named `my-program`you would use `env!("CARGO_BIN_EXE_my-program")`.
Misc
----
- [Certain checks in the `const_err` lint were deemed unrelated to const
evaluation][69185], and have been moved to the `unconditional_panic` and
`arithmetic_overflow` lints.
Compatibility Notes
-------------------
- [Having trailing syntax in the `assert!` macro is now a hard error.][69548] This
has been a warning since 1.36.0.
- [Fixed `Self` not having the correctly inferred type.][69340] This incorrectly
led to some instances being accepted, and now correctly emits a hard error.
[69340]: https://github.com/rust-lang/rust/pull/69340
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.
- [All components are now built with `opt-level=3` instead of `2`.][67878]
- [Improved how rustc generates drop code.][67332]
- [Improved performance from `#[inline]`-ing certain hot functions.][69256]
- [traits: preallocate 2 Vecs of known initial size][69022]
- [Avoid exponential behaviour when relating types][68772]
- [Skip `Drop` terminators for enum variants without drop glue][68943]
- [Improve performance of coherence checks][68966]
- [Deduplicate types in the generator witness][68672]
- [Invert control in struct_lint_level.][68725]
[67332]: https://github.com/rust-lang/rust/pull/67332/
[67429]: https://github.com/rust-lang/rust/pull/67429/
[67637]: https://github.com/rust-lang/rust/pull/67637/
[67642]: https://github.com/rust-lang/rust/pull/67642/
[67878]: https://github.com/rust-lang/rust/pull/67878/
[67885]: https://github.com/rust-lang/rust/pull/67885/
[68129]: https://github.com/rust-lang/rust/pull/68129/
[68672]: https://github.com/rust-lang/rust/pull/68672/
[68725]: https://github.com/rust-lang/rust/pull/68725/
[68728]: https://github.com/rust-lang/rust/pull/68728/
[68738]: https://github.com/rust-lang/rust/pull/68738/
[68742]: https://github.com/rust-lang/rust/pull/68742/
[68764]: https://github.com/rust-lang/rust/pull/68764/
[68772]: https://github.com/rust-lang/rust/pull/68772/
[68943]: https://github.com/rust-lang/rust/pull/68943/
[68952]: https://github.com/rust-lang/rust/pull/68952/
[68966]: https://github.com/rust-lang/rust/pull/68966/
[68984]: https://github.com/rust-lang/rust/pull/68984/
[69022]: https://github.com/rust-lang/rust/pull/69022/
[69185]: https://github.com/rust-lang/rust/pull/69185/
[69194]: https://github.com/rust-lang/rust/pull/69194/
[69201]: https://github.com/rust-lang/rust/pull/69201/
[69227]: https://github.com/rust-lang/rust/pull/69227/
[69548]: https://github.com/rust-lang/rust/pull/69548/
[69256]: https://github.com/rust-lang/rust/pull/69256/
[69361]: https://github.com/rust-lang/rust/pull/69361/
[69366]: https://github.com/rust-lang/rust/pull/69366/
[69538]: https://github.com/rust-lang/rust/pull/69538/
[cargo/7823]: https://github.com/rust-lang/cargo/pull/7823
[cargo/7697]: https://github.com/rust-lang/cargo/pull/7697
[`Once::is_completed`]: https://doc.rust-lang.org/std/sync/struct.Once.html#method.is_completed
[`f32::LOG10_2`]: https://doc.rust-lang.org/std/f32/consts/constant.LOG10_2.html
[`f32::LOG2_10`]: https://doc.rust-lang.org/std/f32/consts/constant.LOG2_10.html
[`f64::LOG10_2`]: https://doc.rust-lang.org/std/f64/consts/constant.LOG10_2.html
[`f64::LOG2_10`]: https://doc.rust-lang.org/std/f64/consts/constant.LOG2_10.html
[`iter::once_with`]: https://doc.rust-lang.org/std/iter/fn.once_with.html
Version 1.42.0 (2020-03-12)
==========================
Language
--------
- [You can now use the slice pattern syntax with subslices.][67712] e.g.
```rust
fn foo(words: &[&str]) {
match words {
["Hello", "World", "!", ..] => println!("Hello World!"),
["Foo", "Bar", ..] => println!("Baz"),
rest => println!("{:?}", rest),
}
}
```
- [You can now use `#[repr(transparent)]` on univariant `enum`s.][68122] Meaning
that you can create an enum that has the exact layout and ABI of the type
it contains.
- [You can now use outer attribute procedural macros on inline modules.][64273]
- [There are some *syntax-only* changes:][67131]
- `default` is syntactically allowed before items in `trait` definitions.
- Items in `impl`s (i.e. `const`s, `type`s, and `fn`s) may syntactically
leave out their bodies in favor of `;`.
- Bounds on associated types in `impl`s are now syntactically allowed
(e.g. `type Foo: Ord;`).
- `...` (the C-variadic type) may occur syntactically directly as the type of
any function parameter.
These are still rejected *semantically*, so you will likely receive an error
but these changes can be seen and parsed by procedural macros and
conditional compilation.
Compiler
--------
- [Added tier 2\* support for `armv7a-none-eabi`.][68253]
- [Added tier 2 support for `riscv64gc-unknown-linux-gnu`.][68339]
- [`Option::{expect,unwrap}` and
`Result::{expect, expect_err, unwrap, unwrap_err}` now produce panic messages
pointing to the location where they were called, rather than
`core`'s internals. ][67887]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`iter::Empty` now implements `Send` and `Sync` for any `T`.][68348]
- [`Pin::{map_unchecked, map_unchecked_mut}` no longer require the return type
to implement `Sized`.][67935]
- [`io::Cursor` now derives `PartialEq` and `Eq`.][67233]
- [`Layout::new` is now `const`.][66254]
- [Added Standard Library support for `riscv64gc-unknown-linux-gnu`.][66899]
Stabilized APIs
---------------
- [`CondVar::wait_while`]
- [`CondVar::wait_timeout_while`]
- [`DebugMap::key`]
- [`DebugMap::value`]
- [`ManuallyDrop::take`]
- [`matches!`]
- [`ptr::slice_from_raw_parts_mut`]
- [`ptr::slice_from_raw_parts`]
Cargo
-----
- [You no longer need to include `extern crate proc_macro;` to be able to
`use proc_macro;` in the `2018` edition.][cargo/7700]
Compatibility Notes
-------------------
- [`Error::description` has been deprecated, and its use will now produce a
warning.][66919] It's recommended to use `Display`/`to_string` instead.
[68253]: https://github.com/rust-lang/rust/pull/68253/
[68348]: https://github.com/rust-lang/rust/pull/68348/
[67935]: https://github.com/rust-lang/rust/pull/67935/
[68339]: https://github.com/rust-lang/rust/pull/68339/
[68122]: https://github.com/rust-lang/rust/pull/68122/
[64273]: https://github.com/rust-lang/rust/pull/64273/
[67712]: https://github.com/rust-lang/rust/pull/67712/
[67887]: https://github.com/rust-lang/rust/pull/67887/
[67131]: https://github.com/rust-lang/rust/pull/67131/
[67233]: https://github.com/rust-lang/rust/pull/67233/
[66899]: https://github.com/rust-lang/rust/pull/66899/
[66919]: https://github.com/rust-lang/rust/pull/66919/
[66254]: https://github.com/rust-lang/rust/pull/66254/
[cargo/7700]: https://github.com/rust-lang/cargo/pull/7700
[`DebugMap::key`]: https://doc.rust-lang.org/stable/std/fmt/struct.DebugMap.html#method.key
[`DebugMap::value`]: https://doc.rust-lang.org/stable/std/fmt/struct.DebugMap.html#method.value
[`ManuallyDrop::take`]: https://doc.rust-lang.org/stable/std/mem/struct.ManuallyDrop.html#method.take
[`matches!`]: https://doc.rust-lang.org/stable/std/macro.matches.html
[`ptr::slice_from_raw_parts_mut`]: https://doc.rust-lang.org/stable/std/ptr/fn.slice_from_raw_parts_mut.html
[`ptr::slice_from_raw_parts`]: https://doc.rust-lang.org/stable/std/ptr/fn.slice_from_raw_parts.html
[`CondVar::wait_while`]: https://doc.rust-lang.org/stable/std/sync/struct.Condvar.html#method.wait_while
[`CondVar::wait_timeout_while`]: https://doc.rust-lang.org/stable/std/sync/struct.Condvar.html#method.wait_timeout_while
Version 1.41.1 (2020-02-27)
===========================
* [Always check types of static items][69145]
* [Always check lifetime bounds of `Copy` impls][69145]
* [Fix miscompilation in callers of `Layout::repeat`][69225]
* [Rust 1.41.0 was announced as the last Rust release with tier 1 or tier 2 support for 32-bit Apple targets][apple-32bit-drop].
That announcement did not expect a patch release. 1.41.1 also includes release binaries for these targets.
[69225]: https://github.com/rust-lang/rust/issues/69225
[69145]: https://github.com/rust-lang/rust/pull/69145
Version 1.41.0 (2020-01-30)
===========================
Language
--------
- [You can now pass type parameters to foreign items when implementing
traits.][65879] E.g. You can now write `impl From for Vec {}`.
- [You can now arbitrarily nest receiver types in the `self` position.][64325] E.g. you can
now write `fn foo(self: Box