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/)
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/)
Misc
----
- [rustdoc: add `--test-builder-wrapper` arg to support wrappers such as RUSTC_WRAPPER when building doctests](https://github.com/rust-lang/rust/pull/114651/)
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 compatiblity 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 config.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 results 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 `config.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>) {}`. Previously only `Self`, `&Self`,
`&mut Self`, `Arc`, `Rc`, and `Box` were allowed.
- [You can now use any valid identifier in a `format_args` macro.][66847]
Previously identifiers starting with an underscore were not allowed.
- [Visibility modifiers (e.g. `pub`) are now syntactically allowed on trait items and
enum variants.][66183] These are still rejected semantically, but
can be seen and parsed by procedural macros and conditional compilation.
- [You can now define a Rust `extern "C"` function with `Box` and use `T*` as the corresponding
type on the C side.][62514] Please see [the documentation][box-memory-layout] for more information,
including the important caveat about preferring to avoid `Box` in Rust signatures for functions defined in C.
[box-memory-layout]: https://doc.rust-lang.org/std/boxed/index.html#memory-layout
Compiler
--------
- [Rustc will now warn if you have unused loop `'label`s.][66325]
- [Removed support for the `i686-unknown-dragonfly` target.][67255]
- [Added tier 3 support\* for the `riscv64gc-unknown-linux-gnu` target.][66661]
- [You can now pass an arguments file passing the `@path` syntax
to rustc.][66172] Note that the format differs somewhat from what is
found in other tooling; please see [the documentation][argfile-docs] for
more information.
- [You can now provide `--extern` flag without a path, indicating that it is
available from the search path or specified with an `-L` flag.][64882]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
[argfile-docs]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#path-load-command-line-flags-from-a-path
Libraries
---------
- [The `core::panic` module is now stable.][66771] It was already stable
through `std`.
- [`NonZero*` numerics now implement `From` if it's a smaller integer
width.][66277] E.g. `NonZeroU16` now implements `From`.
- [`MaybeUninit` now implements `fmt::Debug`.][65013]
Stabilized APIs
---------------
- [`Result::map_or`]
- [`Result::map_or_else`]
- [`std::rc::Weak::weak_count`]
- [`std::rc::Weak::strong_count`]
- [`std::sync::Weak::weak_count`]
- [`std::sync::Weak::strong_count`]
Cargo
-----
- [Cargo will now document all the private items for binary crates
by default.][cargo/7593]
- [`cargo-install` will now reinstall the package if it detects that it is out
of date.][cargo/7560]
- [Cargo.lock now uses a more git friendly format that should help to reduce
merge conflicts.][cargo/7579]
- [You can now override specific dependencies's build settings][cargo/7591] E.g.
`[profile.dev.package.image] opt-level = 2` sets the `image` crate's
optimisation level to `2` for debug builds. You can also use
`[profile..build-override]` to override build scripts and
their dependencies.
Misc
----
- [You can now specify `edition` in documentation code blocks to compile the block
for that edition.][66238] E.g. `edition2018` tells rustdoc that the code sample
should be compiled the 2018 edition of Rust.
- [You can now provide custom themes to rustdoc with `--theme`, and check the
current theme with `--check-theme`.][54733]
- [You can use `#[cfg(doc)]` to compile an item when building documentation.][61351]
Compatibility Notes
-------------------
- [As previously announced 1.41 will be the last tier 1 release for 32-bit
Apple targets.][apple-32bit-drop] This means that the source code is still
available to build, but the targets are no longer being tested and release
binaries for those platforms will no longer be distributed by the Rust project.
Please refer to the linked blog post for more information.
[54733]: https://github.com/rust-lang/rust/pull/54733/
[61351]: https://github.com/rust-lang/rust/pull/61351/
[62514]: https://github.com/rust-lang/rust/pull/62514/
[67255]: https://github.com/rust-lang/rust/pull/67255/
[66661]: https://github.com/rust-lang/rust/pull/66661/
[66771]: https://github.com/rust-lang/rust/pull/66771/
[66847]: https://github.com/rust-lang/rust/pull/66847/
[66238]: https://github.com/rust-lang/rust/pull/66238/
[66277]: https://github.com/rust-lang/rust/pull/66277/
[66325]: https://github.com/rust-lang/rust/pull/66325/
[66172]: https://github.com/rust-lang/rust/pull/66172/
[66183]: https://github.com/rust-lang/rust/pull/66183/
[65879]: https://github.com/rust-lang/rust/pull/65879/
[65013]: https://github.com/rust-lang/rust/pull/65013/
[64882]: https://github.com/rust-lang/rust/pull/64882/
[64325]: https://github.com/rust-lang/rust/pull/64325/
[cargo/7560]: https://github.com/rust-lang/cargo/pull/7560/
[cargo/7579]: https://github.com/rust-lang/cargo/pull/7579/
[cargo/7591]: https://github.com/rust-lang/cargo/pull/7591/
[cargo/7593]: https://github.com/rust-lang/cargo/pull/7593/
[`Result::map_or_else`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or_else
[`Result::map_or`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or
[`std::rc::Weak::weak_count`]: https://doc.rust-lang.org/std/rc/struct.Weak.html#method.weak_count
[`std::rc::Weak::strong_count`]: https://doc.rust-lang.org/std/rc/struct.Weak.html#method.strong_count
[`std::sync::Weak::weak_count`]: https://doc.rust-lang.org/std/sync/struct.Weak.html#method.weak_count
[`std::sync::Weak::strong_count`]: https://doc.rust-lang.org/std/sync/struct.Weak.html#method.strong_count
[apple-32bit-drop]: https://blog.rust-lang.org/2020/01/03/reducing-support-for-32-bit-apple-targets.html
Version 1.40.0 (2019-12-19)
===========================
Language
--------
- [You can now use tuple `struct`s and tuple `enum` variant's constructors in
`const` contexts.][65188] e.g.
```rust
pub struct Point(i32, i32);
const ORIGIN: Point = {
let constructor = Point;
constructor(0, 0)
};
```
- [You can now mark `struct`s, `enum`s, and `enum` variants with the `#[non_exhaustive]` attribute to
indicate that there may be variants or fields added in the future.][64639]
For example this requires adding a wild-card branch (`_ => {}`) to any match
statements on a non-exhaustive `enum`. [(RFC 2008)]
- [You can now use function-like procedural macros in `extern` blocks and in
type positions.][63931] e.g. `type Generated = macro!();`
- [Function-like and attribute procedural macros can now emit
`macro_rules!` items, so you can now have your macros generate macros.][64035]
- [The `meta` pattern matcher in `macro_rules!` now correctly matches the modern
attribute syntax.][63674] For example `(#[$m:meta])` now matches `#[attr]`,
`#[attr{tokens}]`, `#[attr[tokens]]`, and `#[attr(tokens)]`.
Compiler
--------
- [Added tier 3 support\* for the
`thumbv7neon-unknown-linux-musleabihf` target.][66103]
- [Added tier 3 support for the
`aarch64-unknown-none-softfloat` target.][64589]
- [Added tier 3 support for the `mips64-unknown-linux-muslabi64`, and
`mips64el-unknown-linux-muslabi64` targets.][65843]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [The `is_power_of_two` method on unsigned numeric types is now a `const` function.][65092]
Stabilized APIs
---------------
- [`BTreeMap::get_key_value`]
- [`HashMap::get_key_value`]
- [`Option::as_deref_mut`]
- [`Option::as_deref`]
- [`Option::flatten`]
- [`UdpSocket::peer_addr`]
- [`f32::to_be_bytes`]
- [`f32::to_le_bytes`]
- [`f32::to_ne_bytes`]
- [`f64::to_be_bytes`]
- [`f64::to_le_bytes`]
- [`f64::to_ne_bytes`]
- [`f32::from_be_bytes`]
- [`f32::from_le_bytes`]
- [`f32::from_ne_bytes`]
- [`f64::from_be_bytes`]
- [`f64::from_le_bytes`]
- [`f64::from_ne_bytes`]
- [`mem::take`]
- [`slice::repeat`]
- [`todo!`]
Cargo
-----
- [Cargo will now always display warnings, rather than only on
fresh builds.][cargo/7450]
- [Feature flags (except `--all-features`) passed to a virtual workspace will
now produce an error.][cargo/7507] Previously these flags were ignored.
- [You can now publish `dev-dependencies` without including
a `version`.][cargo/7333]
Misc
----
- [You can now specify the `#[cfg(doctest)]` attribute to include an item only
when running documentation tests with `rustdoc`.][63803]
Compatibility Notes
-------------------
- [As previously announced, any previous NLL warnings in the 2015 edition are
now hard errors.][64221]
- [The `include!` macro will now warn if it failed to include the
entire file.][64284] The `include!` macro unintentionally only includes the
first _expression_ in a file, and this can be unintuitive. This will become
either a hard error in a future release, or the behavior may be fixed to include all expressions as expected.
- [Using `#[inline]` on function prototypes and consts now emits a warning under
`unused_attribute` lint.][65294] Using `#[inline]` anywhere else inside traits
or `extern` blocks now correctly emits a hard error.
[65294]: https://github.com/rust-lang/rust/pull/65294/
[66103]: https://github.com/rust-lang/rust/pull/66103/
[65843]: https://github.com/rust-lang/rust/pull/65843/
[65188]: https://github.com/rust-lang/rust/pull/65188/
[65092]: https://github.com/rust-lang/rust/pull/65092/
[64589]: https://github.com/rust-lang/rust/pull/64589/
[64639]: https://github.com/rust-lang/rust/pull/64639/
[64221]: https://github.com/rust-lang/rust/pull/64221/
[64284]: https://github.com/rust-lang/rust/pull/64284/
[63931]: https://github.com/rust-lang/rust/pull/63931/
[64035]: https://github.com/rust-lang/rust/pull/64035/
[63674]: https://github.com/rust-lang/rust/pull/63674/
[63803]: https://github.com/rust-lang/rust/pull/63803/
[cargo/7450]: https://github.com/rust-lang/cargo/pull/7450/
[cargo/7507]: https://github.com/rust-lang/cargo/pull/7507/
[cargo/7333]: https://github.com/rust-lang/cargo/pull/7333/
[(rfc 2008)]: https://rust-lang.github.io/rfcs/2008-non-exhaustive.html
[`f32::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_be_bytes
[`f32::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_le_bytes
[`f32::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_ne_bytes
[`f64::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_be_bytes
[`f64::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_le_bytes
[`f64::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_ne_bytes
[`f32::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_be_bytes
[`f32::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_le_bytes
[`f32::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_ne_bytes
[`f64::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_be_bytes
[`f64::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_le_bytes
[`f64::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_ne_bytes
[`option::flatten`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.flatten
[`option::as_deref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref
[`option::as_deref_mut`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref_mut
[`hashmap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.get_key_value
[`btreemap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.get_key_value
[`slice::repeat`]: https://doc.rust-lang.org/std/primitive.slice.html#method.repeat
[`mem::take`]: https://doc.rust-lang.org/std/mem/fn.take.html
[`udpsocket::peer_addr`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peer_addr
[`todo!`]: https://doc.rust-lang.org/std/macro.todo.html
Version 1.39.0 (2019-11-07)
===========================
Language
--------
- [You can now create `async` functions and blocks with `async fn`, `async move {}`, and
`async {}` respectively, and you can now call `.await` on async expressions.][63209]
- [You can now use certain attributes on function, closure, and function pointer
parameters.][64010] These attributes include `cfg`, `cfg_attr`, `allow`, `warn`,
`deny`, `forbid` as well as inert helper attributes used by procedural macro
attributes applied to items. e.g.
```rust
fn len(
#[cfg(windows)] slice: &[u16],
#[cfg(not(windows))] slice: &[u8],
) -> usize {
slice.len()
}
```
- [You can now take shared references to bind-by-move patterns in the `if` guards
of `match` arms.][63118] e.g.
```rust
fn main() {
let array: Box<[u8; 4]> = Box::new([1, 2, 3, 4]);
match array {
nums
// ---- `nums` is bound by move.
if nums.iter().sum::() == 10
// ^------ `.iter()` implicitly takes a reference to `nums`.
=> {
drop(nums);
// ----------- Legal as `nums` was bound by move and so we have ownership.
}
_ => unreachable!(),
}
}
```
Compiler
--------
- [Added tier 3\* support for the `i686-unknown-uefi` target.][64334]
- [Added tier 3 support for the `sparc64-unknown-openbsd` target.][63595]
- [rustc will now trim code snippets in diagnostics to fit in your terminal.][63402]
**Note** Cargo currently doesn't use this feature. Refer to
[cargo#7315][cargo/7315] to track this feature's progress.
- [You can now pass `--show-output` argument to test binaries to print the
output of successful tests.][62600]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`Vec::new` and `String::new` are now `const` functions.][64028]
- [`LinkedList::new` is now a `const` function.][63684]
- [`str::len`, `[T]::len` and `str::as_bytes` are now `const` functions.][63770]
- [The `abs`, `wrapping_abs`, and `overflowing_abs` numeric functions are
now `const`.][63786]
Stabilized APIs
---------------
- [`Pin::into_inner`]
- [`Instant::checked_duration_since`]
- [`Instant::saturating_duration_since`]
Cargo
-----
- [You can now publish git dependencies if supplied with a `version`.][cargo/7237]
- [The `--all` flag has been renamed to `--workspace`.][cargo/7241] Using
`--all` is now deprecated.
Misc
----
- [You can now pass `-Clinker` to rustdoc to control the linker used
for compiling doctests.][63834]
Compatibility Notes
-------------------
- [Code that was previously accepted by the old borrow checker, but rejected by
the NLL borrow checker is now a hard error in Rust 2018.][63565] This was
previously a warning, and will also become a hard error in the Rust 2015
edition in the 1.40.0 release.
- [`rustdoc` now requires `rustc` to be installed and in the same directory to
run tests.][63827] This should improve performance when running a large
amount of doctests.
- [The `try!` macro will now issue a deprecation warning.][62672] It is
recommended to use the `?` operator instead.
- [`asinh(-0.0)` now correctly returns `-0.0`.][63698] Previously this
returned `0.0`.
[62600]: https://github.com/rust-lang/rust/pull/62600/
[62672]: https://github.com/rust-lang/rust/pull/62672/
[63118]: https://github.com/rust-lang/rust/pull/63118/
[63209]: https://github.com/rust-lang/rust/pull/63209/
[63402]: https://github.com/rust-lang/rust/pull/63402/
[63565]: https://github.com/rust-lang/rust/pull/63565/
[63595]: https://github.com/rust-lang/rust/pull/63595/
[63684]: https://github.com/rust-lang/rust/pull/63684/
[63698]: https://github.com/rust-lang/rust/pull/63698/
[63770]: https://github.com/rust-lang/rust/pull/63770/
[63786]: https://github.com/rust-lang/rust/pull/63786/
[63827]: https://github.com/rust-lang/rust/pull/63827/
[63834]: https://github.com/rust-lang/rust/pull/63834/
[64010]: https://github.com/rust-lang/rust/pull/64010/
[64028]: https://github.com/rust-lang/rust/pull/64028/
[64334]: https://github.com/rust-lang/rust/pull/64334/
[cargo/7237]: https://github.com/rust-lang/cargo/pull/7237/
[cargo/7241]: https://github.com/rust-lang/cargo/pull/7241/
[cargo/7315]: https://github.com/rust-lang/cargo/pull/7315/
[`Pin::into_inner`]: https://doc.rust-lang.org/std/pin/struct.Pin.html#method.into_inner
[`Instant::checked_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_duration_since
[`Instant::saturating_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.saturating_duration_since
Version 1.38.0 (2019-09-26)
==========================
Language
--------
- [The `#[global_allocator]` attribute can now be used in submodules.][62735]
- [The `#[deprecated]` attribute can now be used on macros.][62042]
Compiler
--------
- [Added pipelined compilation support to `rustc`.][62766] This will
improve compilation times in some cases. For further information please refer
to the [_"Evaluating pipelined rustc compilation"_][pipeline-internals] thread.
- [Added tier 3\* support for the `aarch64-uwp-windows-msvc`, `i686-uwp-windows-gnu`,
`i686-uwp-windows-msvc`, `x86_64-uwp-windows-gnu`, and
`x86_64-uwp-windows-msvc` targets.][60260]
- [Added tier 3 support for the `armv7-unknown-linux-gnueabi` and
`armv7-unknown-linux-musleabi` targets.][63107]
- [Added tier 3 support for the `hexagon-unknown-linux-musl` target.][62814]
- [Added tier 3 support for the `riscv32i-unknown-none-elf` target.][62784]
- [Upgraded to LLVM 9.][62592]
\* Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
Libraries
---------
- [`ascii::EscapeDefault` now implements `Clone` and `Display`.][63421]
- [Derive macros for prelude traits (e.g. `Clone`, `Debug`, `Hash`) are now
available at the same path as the trait.][63056] (e.g. The `Clone` derive macro
is available at `std::clone::Clone`). This also makes all built-in macros
available in `std`/`core` root. e.g. `std::include_bytes!`.
- [`str::Chars` now implements `Debug`.][63000]
- [`slice::{concat, connect, join}` now accepts `&[T]` in addition to `&T`.][62528]
- [`*const T` and `*mut T` now implement `marker::Unpin`.][62583]
- [`Arc<[T]>` and `Rc<[T]>` now implement `FromIterator`.][61953]
- [Added euclidean remainder and division operations (`div_euclid`,
`rem_euclid`) to all numeric primitives.][61884] Additionally `checked`,
`overflowing`, and `wrapping` versions are available for all
integer primitives.
- [`thread::AccessError` now implements `Clone`, `Copy`, `Eq`, `Error`, and
`PartialEq`.][61491]
- [`iter::{StepBy, Peekable, Take}` now implement `DoubleEndedIterator`.][61457]
Stabilized APIs
---------------
- [`<*const T>::cast`]
- [`<*mut T>::cast`]
- [`Duration::as_secs_f32`]
- [`Duration::as_secs_f64`]
- [`Duration::div_f32`]
- [`Duration::div_f64`]
- [`Duration::from_secs_f32`]
- [`Duration::from_secs_f64`]
- [`Duration::mul_f32`]
- [`Duration::mul_f64`]
- [`any::type_name`]
Cargo
-----
- [Added pipelined compilation support to `cargo`.][cargo/7143]
- [You can now pass the `--features` option multiple times to enable
multiple features.][cargo/7084]
Rustdoc
-------
- [Documentation on `pub use` statements is prepended to the documentation of the re-exported item][63048]
Misc
----
- [`rustc` will now warn about some incorrect uses of
`mem::{uninitialized, zeroed}` that are known to cause undefined behaviour.][63346]
Compatibility Notes
-------------------
- The [`x86_64-unknown-uefi` platform can not be built][62785] with rustc
1.38.0.
- The [`armv7-unknown-linux-gnueabihf` platform is known to have
issues][62896] with certain crates such as libc.
[60260]: https://github.com/rust-lang/rust/pull/60260/
[61457]: https://github.com/rust-lang/rust/pull/61457/
[61491]: https://github.com/rust-lang/rust/pull/61491/
[61884]: https://github.com/rust-lang/rust/pull/61884/
[61953]: https://github.com/rust-lang/rust/pull/61953/
[62042]: https://github.com/rust-lang/rust/pull/62042/
[62528]: https://github.com/rust-lang/rust/pull/62528/
[62583]: https://github.com/rust-lang/rust/pull/62583/
[62735]: https://github.com/rust-lang/rust/pull/62735/
[62766]: https://github.com/rust-lang/rust/pull/62766/
[62784]: https://github.com/rust-lang/rust/pull/62784/
[62592]: https://github.com/rust-lang/rust/pull/62592/
[62785]: https://github.com/rust-lang/rust/issues/62785/
[62814]: https://github.com/rust-lang/rust/pull/62814/
[62896]: https://github.com/rust-lang/rust/issues/62896/
[63000]: https://github.com/rust-lang/rust/pull/63000/
[63056]: https://github.com/rust-lang/rust/pull/63056/
[63107]: https://github.com/rust-lang/rust/pull/63107/
[63346]: https://github.com/rust-lang/rust/pull/63346/
[63421]: https://github.com/rust-lang/rust/pull/63421/
[cargo/7084]: https://github.com/rust-lang/cargo/pull/7084/
[cargo/7143]: https://github.com/rust-lang/cargo/pull/7143/
[63048]: https://github.com/rust-lang/rust/pull/63048
[`<*const T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast
[`<*mut T>::cast`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.cast
[`Duration::as_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f32
[`Duration::as_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs_f64
[`Duration::div_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f32
[`Duration::div_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.div_f64
[`Duration::from_secs_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f32
[`Duration::from_secs_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_secs_f64
[`Duration::mul_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f32
[`Duration::mul_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f64
[`any::type_name`]: https://doc.rust-lang.org/std/any/fn.type_name.html
[platform-support-doc]: https://doc.rust-lang.org/nightly/rustc/platform-support.html
[pipeline-internals]: https://internals.rust-lang.org/t/evaluating-pipelined-rustc-compilation/10199
Version 1.37.0 (2019-08-15)
==========================
Language
--------
- `#[must_use]` will now warn if the type is contained in a [tuple][61100],
[`Box`][62228], or an [array][62235] and unused.
- [You can now use the `cfg` and `cfg_attr` attributes on
generic parameters.][61547]
- [You can now use enum variants through type alias.][61682] e.g. You can
write the following:
```rust
type MyOption = Option;
fn increment_or_zero(x: MyOption) -> u8 {
match x {
MyOption::Some(y) => y + 1,
MyOption::None => 0,
}
}
```
- [You can now use `_` as an identifier for consts.][61347] e.g. You can write
`const _: u32 = 5;`.
- [You can now use `#[repr(align(X)]` on enums.][61229]
- [The `?` Kleene macro operator is now available in the
2015 edition.][60932]
Compiler
--------
- [You can now enable Profile-Guided Optimization with the `-C profile-generate`
and `-C profile-use` flags.][61268] For more information on how to use profile
guided optimization, please refer to the [rustc book][rustc-book-pgo].
- [The `rust-lldb` wrapper script should now work again.][61827]
Libraries
---------
- [`mem::MaybeUninit` is now ABI-compatible with `T`.][61802]
Stabilized APIs
---------------
- [`BufReader::buffer`]
- [`BufWriter::buffer`]
- [`Cell::from_mut`]
- [`Cell<[T]>::as_slice_of_cells`][`Cell::as_slice_of_cells`]
- [`DoubleEndedIterator::nth_back`]
- [`Option::xor`]
- [`Wrapping::reverse_bits`]
- [`i128::reverse_bits`]
- [`i16::reverse_bits`]
- [`i32::reverse_bits`]
- [`i64::reverse_bits`]
- [`i8::reverse_bits`]
- [`isize::reverse_bits`]
- [`slice::copy_within`]
- [`u128::reverse_bits`]
- [`u16::reverse_bits`]
- [`u32::reverse_bits`]
- [`u64::reverse_bits`]
- [`u8::reverse_bits`]
- [`usize::reverse_bits`]
Cargo
-----
- [`Cargo.lock` files are now included by default when publishing executable crates
with executables.][cargo/7026]
- [You can now specify `default-run="foo"` in `[package]` to specify the
default executable to use for `cargo run`.][cargo/7056]
Misc
----
Compatibility Notes
-------------------
- [Using `...` for inclusive range patterns will now warn by default.][61342]
Please transition your code to using the `..=` syntax for inclusive
ranges instead.
- [Using a trait object without the `dyn` will now warn by default.][61203]
Please transition your code to use `dyn Trait` for trait objects instead.
[62228]: https://github.com/rust-lang/rust/pull/62228/
[62235]: https://github.com/rust-lang/rust/pull/62235/
[61802]: https://github.com/rust-lang/rust/pull/61802/
[61827]: https://github.com/rust-lang/rust/pull/61827/
[61547]: https://github.com/rust-lang/rust/pull/61547/
[61682]: https://github.com/rust-lang/rust/pull/61682/
[61268]: https://github.com/rust-lang/rust/pull/61268/
[61342]: https://github.com/rust-lang/rust/pull/61342/
[61347]: https://github.com/rust-lang/rust/pull/61347/
[61100]: https://github.com/rust-lang/rust/pull/61100/
[61203]: https://github.com/rust-lang/rust/pull/61203/
[61229]: https://github.com/rust-lang/rust/pull/61229/
[60932]: https://github.com/rust-lang/rust/pull/60932/
[cargo/7026]: https://github.com/rust-lang/cargo/pull/7026/
[cargo/7056]: https://github.com/rust-lang/cargo/pull/7056/
[`BufReader::buffer`]: https://doc.rust-lang.org/std/io/struct.BufReader.html#method.buffer
[`BufWriter::buffer`]: https://doc.rust-lang.org/std/io/struct.BufWriter.html#method.buffer
[`Cell::from_mut`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.from_mut
[`Cell::as_slice_of_cells`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_slice_of_cells
[`DoubleEndedIterator::nth_back`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.nth_back
[`Option::xor`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.xor
[`Wrapping::reverse_bits`]: https://doc.rust-lang.org/std/num/struct.Wrapping.html#method.reverse_bits
[`i128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i128.html#method.reverse_bits
[`i16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i16.html#method.reverse_bits
[`i32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i32.html#method.reverse_bits
[`i64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i64.html#method.reverse_bits
[`i8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i8.html#method.reverse_bits
[`isize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.isize.html#method.reverse_bits
[`slice::copy_within`]: https://doc.rust-lang.org/std/primitive.slice.html#method.copy_within
[`u128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u128.html#method.reverse_bits
[`u16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u16.html#method.reverse_bits
[`u32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u32.html#method.reverse_bits
[`u64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u64.html#method.reverse_bits
[`u8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u8.html#method.reverse_bits
[`usize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.usize.html#method.reverse_bits
[rustc-book-pgo]: https://doc.rust-lang.org/rustc/profile-guided-optimization.html
Version 1.36.0 (2019-07-04)
==========================
Language
--------
- [Non-Lexical Lifetimes are now enabled on the 2015 edition.][59114]
- [The order of traits in trait objects no longer affects the semantics of that
object.][59445] e.g. `dyn Send + fmt::Debug` is now equivalent to
`dyn fmt::Debug + Send`, where this was previously not the case.
Libraries
---------
- [`HashMap`'s implementation has been replaced with `hashbrown::HashMap` implementation.][58623]
- [`TryFromSliceError` now implements `From`.][60318]
- [`mem::needs_drop` is now available as a const fn.][60364]
- [`alloc::Layout::from_size_align_unchecked` is now available as a const fn.][60370]
- [`String` now implements `BorrowMut`.][60404]
- [`io::Cursor` now implements `Default`.][60234]
- [Both `NonNull::{dangling, cast}` are now const fns.][60244]
- [The `alloc` crate is now stable.][59675] `alloc` allows you to use a subset
of `std` (e.g. `Vec`, `Box`, `Arc`) in `#![no_std]` environments if the
environment has access to heap memory allocation.
- [`String` now implements `From<&String>`.][59825]
- [You can now pass multiple arguments to the `dbg!` macro.][59826] `dbg!` will
return a tuple of each argument when there is multiple arguments.
- [`Result::{is_err, is_ok}` are now `#[must_use]` and will produce a warning if
not used.][59648]
Stabilized APIs
---------------
- [`VecDeque::rotate_left`]
- [`VecDeque::rotate_right`]
- [`Iterator::copied`]
- [`io::IoSlice`]
- [`io::IoSliceMut`]
- [`Read::read_vectored`]
- [`Write::write_vectored`]
- [`str::as_mut_ptr`]
- [`mem::MaybeUninit`]
- [`pointer::align_offset`]
- [`future::Future`]
- [`task::Context`]
- [`task::RawWaker`]
- [`task::RawWakerVTable`]
- [`task::Waker`]
- [`task::Poll`]
Cargo
-----
- [Cargo will now produce an error if you attempt to use the name of a required dependency as a feature.][cargo/6860]
- [You can now pass the `--offline` flag to run cargo without accessing the network.][cargo/6934]
You can find further change's in [Cargo's 1.36.0 release notes][cargo-1-36-0].
Clippy
------
There have been numerous additions and fixes to clippy, see [Clippy's 1.36.0 release notes][clippy-1-36-0] for more details.
Misc
----
Compatibility Notes
-------------------
- With the stabilisation of `mem::MaybeUninit`, `mem::uninitialized` use is no
longer recommended, and will be deprecated in 1.39.0.
[60318]: https://github.com/rust-lang/rust/pull/60318/
[60364]: https://github.com/rust-lang/rust/pull/60364/
[60370]: https://github.com/rust-lang/rust/pull/60370/
[60404]: https://github.com/rust-lang/rust/pull/60404/
[60234]: https://github.com/rust-lang/rust/pull/60234/
[60244]: https://github.com/rust-lang/rust/pull/60244/
[58623]: https://github.com/rust-lang/rust/pull/58623/
[59648]: https://github.com/rust-lang/rust/pull/59648/
[59675]: https://github.com/rust-lang/rust/pull/59675/
[59825]: https://github.com/rust-lang/rust/pull/59825/
[59826]: https://github.com/rust-lang/rust/pull/59826/
[59445]: https://github.com/rust-lang/rust/pull/59445/
[59114]: https://github.com/rust-lang/rust/pull/59114/
[cargo/6860]: https://github.com/rust-lang/cargo/pull/6860/
[cargo/6934]: https://github.com/rust-lang/cargo/pull/6934/
[`VecDeque::rotate_left`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.rotate_left
[`VecDeque::rotate_right`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.rotate_right
[`Iterator::copied`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#tymethod.copied
[`io::IoSlice`]: https://doc.rust-lang.org/std/io/struct.IoSlice.html
[`io::IoSliceMut`]: https://doc.rust-lang.org/std/io/struct.IoSliceMut.html
[`Read::read_vectored`]: https://doc.rust-lang.org/std/io/trait.Read.html#method.read_vectored
[`Write::write_vectored`]: https://doc.rust-lang.org/std/io/trait.Write.html#method.write_vectored
[`str::as_mut_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_mut_ptr
[`mem::MaybeUninit`]: https://doc.rust-lang.org/std/mem/union.MaybeUninit.html
[`pointer::align_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.align_offset
[`future::Future`]: https://doc.rust-lang.org/std/future/trait.Future.html
[`task::Context`]: https://doc.rust-lang.org/beta/std/task/struct.Context.html
[`task::RawWaker`]: https://doc.rust-lang.org/beta/std/task/struct.RawWaker.html
[`task::RawWakerVTable`]: https://doc.rust-lang.org/beta/std/task/struct.RawWakerVTable.html
[`task::Waker`]: https://doc.rust-lang.org/beta/std/task/struct.Waker.html
[`task::Poll`]: https://doc.rust-lang.org/beta/std/task/enum.Poll.html
[clippy-1-36-0]: https://github.com/rust-lang/rust-clippy/blob/master/CHANGELOG.md#rust-136
[cargo-1-36-0]: https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-136-2019-07-04
Version 1.35.0 (2019-05-23)
==========================
Language
--------
- [`FnOnce`, `FnMut`, and the `Fn` traits are now implemented for `Box`,
`Box`, and `Box` respectively.][59500]
- [You can now coerce closures into unsafe function pointers.][59580] e.g.
```rust
unsafe fn call_unsafe(func: unsafe fn()) {
func()
}
pub fn main() {
unsafe { call_unsafe(|| {}); }
}
```
Compiler
--------
- [Added the `armv6-unknown-freebsd-gnueabihf` and
`armv7-unknown-freebsd-gnueabihf` targets.][58080]
- [Added the `wasm32-unknown-wasi` target.][59464]
Libraries
---------
- [`Thread` will now show its ID in `Debug` output.][59460]
- [`StdinLock`, `StdoutLock`, and `StderrLock` now implement `AsRawFd`.][59512]
- [`alloc::System` now implements `Default`.][59451]
- [Expanded `Debug` output (`{:#?}`) for structs now has a trailing comma on the
last field.][59076]
- [`char::{ToLowercase, ToUppercase}` now
implement `ExactSizeIterator`.][58778]
- [All `NonZero` numeric types now implement `FromStr`.][58717]
- [Removed the `Read` trait bounds
on the `BufReader::{get_ref, get_mut, into_inner}` methods.][58423]
- [You can now call the `dbg!` macro without any parameters to print the file
and line where it is called.][57847]
- [In place ASCII case conversions are now up to 4× faster.][59283]
e.g. `str::make_ascii_lowercase`
- [`hash_map::{OccupiedEntry, VacantEntry}` now implement `Sync`
and `Send`.][58369]
Stabilized APIs
---------------
- [`f32::copysign`]
- [`f64::copysign`]
- [`RefCell::replace_with`]
- [`RefCell::map_split`]
- [`ptr::hash`]
- [`Range::contains`]
- [`RangeFrom::contains`]
- [`RangeTo::contains`]
- [`RangeInclusive::contains`]
- [`RangeToInclusive::contains`]
- [`Option::copied`]
Cargo
-----
- [You can now set `cargo:rustc-cdylib-link-arg` at build time to pass custom
linker arguments when building a `cdylib`.][cargo/6298] Its usage is highly
platform specific.
Misc
----
- [The Rust toolchain is now available natively for musl based distros.][58575]
[59460]: https://github.com/rust-lang/rust/pull/59460/
[59464]: https://github.com/rust-lang/rust/pull/59464/
[59500]: https://github.com/rust-lang/rust/pull/59500/
[59512]: https://github.com/rust-lang/rust/pull/59512/
[59580]: https://github.com/rust-lang/rust/pull/59580/
[59283]: https://github.com/rust-lang/rust/pull/59283/
[59451]: https://github.com/rust-lang/rust/pull/59451/
[59076]: https://github.com/rust-lang/rust/pull/59076/
[58778]: https://github.com/rust-lang/rust/pull/58778/
[58717]: https://github.com/rust-lang/rust/pull/58717/
[58369]: https://github.com/rust-lang/rust/pull/58369/
[58423]: https://github.com/rust-lang/rust/pull/58423/
[58080]: https://github.com/rust-lang/rust/pull/58080/
[57847]: https://github.com/rust-lang/rust/pull/57847/
[58575]: https://github.com/rust-lang/rust/pull/58575
[cargo/6298]: https://github.com/rust-lang/cargo/pull/6298/
[`f32::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.copysign
[`f64::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.copysign
[`RefCell::replace_with`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.replace_with
[`RefCell::map_split`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.map_split
[`ptr::hash`]: https://doc.rust-lang.org/stable/std/ptr/fn.hash.html
[`Range::contains`]: https://doc.rust-lang.org/std/ops/struct.Range.html#method.contains
[`RangeFrom::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeFrom.html#method.contains
[`RangeTo::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeTo.html#method.contains
[`RangeInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.contains
[`RangeToInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html#method.contains
[`Option::copied`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.copied
Version 1.34.2 (2019-05-14)
===========================
* [Destabilize the `Error::type_id` function due to a security
vulnerability][60785] ([CVE-2019-12083])
[60785]: https://github.com/rust-lang/rust/pull/60785
[CVE-2019-12083]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12083
Version 1.34.1 (2019-04-25)
===========================
* [Fix false positives for the `redundant_closure` Clippy lint][clippy/3821]
* [Fix false positives for the `missing_const_for_fn` Clippy lint][clippy/3844]
* [Fix Clippy panic when checking some macros][clippy/3805]
[clippy/3821]: https://github.com/rust-lang/rust-clippy/pull/3821
[clippy/3844]: https://github.com/rust-lang/rust-clippy/pull/3844
[clippy/3805]: https://github.com/rust-lang/rust-clippy/pull/3805
Version 1.34.0 (2019-04-11)
==========================
Language
--------
- [You can now use `#[deprecated = "reason"]`][58166] as a shorthand for
`#[deprecated(note = "reason")]`. This was previously allowed by mistake
but had no effect.
- [You can now accept token streams in `#[attr()]`,`#[attr[]]`, and
`#[attr{}]` procedural macros.][57367]
- [You can now write `extern crate self as foo;`][57407] to import your
crate's root into the extern prelude.
Compiler
--------
- [You can now target `riscv64imac-unknown-none-elf` and
`riscv64gc-unknown-none-elf`.][58406]
- [You can now enable linker plugin LTO optimisations with
`-C linker-plugin-lto`.][58057] This allows rustc to compile your Rust code
into LLVM bitcode allowing LLVM to perform LTO optimisations across C/C++ FFI
boundaries.
- [You can now target `powerpc64-unknown-freebsd`.][57809]
Libraries
---------
- [The trait bounds have been removed on some of `HashMap`'s and
`HashSet`'s basic methods.][58370] Most notably you no longer require
the `Hash` trait to create an iterator.
- [The `Ord` trait bounds have been removed on some of `BinaryHeap`'s basic
methods.][58421] Most notably you no longer require the `Ord` trait to create
an iterator.
- [The methods `overflowing_neg` and `wrapping_neg` are now `const` functions
for all numeric types.][58044]
- [Indexing a `str` is now generic over all types that
implement `SliceIndex`.][57604]
- [`str::trim`, `str::trim_matches`, `str::trim_{start, end}`, and
`str::trim_{start, end}_matches` are now `#[must_use]`][57106] and will
produce a warning if their returning type is unused.
- [The methods `checked_pow`, `saturating_pow`, `wrapping_pow`, and
`overflowing_pow` are now available for all numeric types.][57873] These are
equivalent to methods such as `wrapping_add` for the `pow` operation.
Stabilized APIs
---------------
#### std & core
* [`Any::type_id`]
* [`Error::type_id`]
* [`atomic::AtomicI16`]
* [`atomic::AtomicI32`]
* [`atomic::AtomicI64`]
* [`atomic::AtomicI8`]
* [`atomic::AtomicU16`]
* [`atomic::AtomicU32`]
* [`atomic::AtomicU64`]
* [`atomic::AtomicU8`]
* [`convert::Infallible`]
* [`convert::TryFrom`]
* [`convert::TryInto`]
* [`iter::from_fn`]
* [`iter::successors`]
* [`num::NonZeroI128`]
* [`num::NonZeroI16`]
* [`num::NonZeroI32`]
* [`num::NonZeroI64`]
* [`num::NonZeroI8`]
* [`num::NonZeroIsize`]
* [`slice::sort_by_cached_key`]
* [`str::escape_debug`]
* [`str::escape_default`]
* [`str::escape_unicode`]
* [`str::split_ascii_whitespace`]
#### std
* [`Instant::checked_add`]
* [`Instant::checked_sub`]
* [`SystemTime::checked_add`]
* [`SystemTime::checked_sub`]
Cargo
-----
- [You can now use alternative registries to crates.io.][cargo/6654]
Misc
----
- [You can now use the `?` operator in your documentation tests without manually
adding `fn main() -> Result<(), _> {}`.][56470]
Compatibility Notes
-------------------
- [`Command::before_exec` is being replaced by the unsafe method
`Command::pre_exec`][58059] and will be deprecated with Rust 1.37.0.
- [Use of `ATOMIC_{BOOL, ISIZE, USIZE}_INIT` is now deprecated][57425] as you
can now use `const` functions in `static` variables.
[58370]: https://github.com/rust-lang/rust/pull/58370/
[58406]: https://github.com/rust-lang/rust/pull/58406/
[58421]: https://github.com/rust-lang/rust/pull/58421/
[58166]: https://github.com/rust-lang/rust/pull/58166/
[58044]: https://github.com/rust-lang/rust/pull/58044/
[58057]: https://github.com/rust-lang/rust/pull/58057/
[58059]: https://github.com/rust-lang/rust/pull/58059/
[57809]: https://github.com/rust-lang/rust/pull/57809/
[57873]: https://github.com/rust-lang/rust/pull/57873/
[57604]: https://github.com/rust-lang/rust/pull/57604/
[57367]: https://github.com/rust-lang/rust/pull/57367/
[57407]: https://github.com/rust-lang/rust/pull/57407/
[57425]: https://github.com/rust-lang/rust/pull/57425/
[57106]: https://github.com/rust-lang/rust/pull/57106/
[56470]: https://github.com/rust-lang/rust/pull/56470/
[cargo/6654]: https://github.com/rust-lang/cargo/pull/6654/
[`Any::type_id`]: https://doc.rust-lang.org/std/any/trait.Any.html#tymethod.type_id
[`Error::type_id`]: https://doc.rust-lang.org/std/error/trait.Error.html#method.type_id
[`atomic::AtomicI16`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI16.html
[`atomic::AtomicI32`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI32.html
[`atomic::AtomicI64`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI64.html
[`atomic::AtomicI8`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicI8.html
[`atomic::AtomicU16`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU16.html
[`atomic::AtomicU32`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU32.html
[`atomic::AtomicU64`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU64.html
[`atomic::AtomicU8`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU8.html
[`convert::Infallible`]: https://doc.rust-lang.org/std/convert/enum.Infallible.html
[`convert::TryFrom`]: https://doc.rust-lang.org/std/convert/trait.TryFrom.html
[`convert::TryInto`]: https://doc.rust-lang.org/std/convert/trait.TryInto.html
[`iter::from_fn`]: https://doc.rust-lang.org/std/iter/fn.from_fn.html
[`iter::successors`]: https://doc.rust-lang.org/std/iter/fn.successors.html
[`num::NonZeroI128`]: https://doc.rust-lang.org/std/num/struct.NonZeroI128.html
[`num::NonZeroI16`]: https://doc.rust-lang.org/std/num/struct.NonZeroI16.html
[`num::NonZeroI32`]: https://doc.rust-lang.org/std/num/struct.NonZeroI32.html
[`num::NonZeroI64`]: https://doc.rust-lang.org/std/num/struct.NonZeroI64.html
[`num::NonZeroI8`]: https://doc.rust-lang.org/std/num/struct.NonZeroI8.html
[`num::NonZeroIsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroIsize.html
[`slice::sort_by_cached_key`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_by_cached_key
[`str::escape_debug`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_debug
[`str::escape_default`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_default
[`str::escape_unicode`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_unicode
[`str::split_ascii_whitespace`]: https://doc.rust-lang.org/std/primitive.str.html#method.split_ascii_whitespace
[`Instant::checked_add`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_add
[`Instant::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_sub
[`SystemTime::checked_add`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_add
[`SystemTime::checked_sub`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_sub
Version 1.33.0 (2019-02-28)
==========================
Language
--------
- [You can now use the `cfg(target_vendor)` attribute.][57465] E.g.
`#[cfg(target_vendor="apple")] fn main() { println!("Hello Apple!"); }`
- [Integer patterns such as in a match expression can now be exhaustive.][56362]
E.g. You can have match statement on a `u8` that covers `0..=255` and
you would no longer be required to have a `_ => unreachable!()` case.
- [You can now have multiple patterns in `if let` and `while let`
expressions.][57532] You can do this with the same syntax as a `match`
expression. E.g.
```rust
enum Creature {
Crab(String),
Lobster(String),
Person(String),
}
fn main() {
let state = Creature::Crab("Ferris");
if let Creature::Crab(name) | Creature::Person(name) = state {
println!("This creature's name is: {}", name);
}
}
```
- [You can now have irrefutable `if let` and `while let` patterns.][57535] Using
this feature will by default produce a warning as this behaviour can be
unintuitive. E.g. `if let _ = 5 {}`
- [You can now use `let` bindings, assignments, expression statements,
and irrefutable pattern destructuring in const functions.][57175]
- [You can now call unsafe const functions.][57067] E.g.
```rust
const unsafe fn foo() -> i32 { 5 }
const fn bar() -> i32 {
unsafe { foo() }
}
```
- [You can now specify multiple attributes in a `cfg_attr` attribute.][57332]
E.g. `#[cfg_attr(all(), must_use, optimize)]`
- [You can now specify a specific alignment with the `#[repr(packed)]`
attribute.][57049] E.g. `#[repr(packed(2))] struct Foo(i16, i32);` is a struct
with an alignment of 2 bytes and a size of 6 bytes.
- [You can now import an item from a module as an `_`.][56303] This allows you to
import a trait's impls, and not have the name in the namespace. E.g.
```rust
use std::io::Read as _;
// Allowed as there is only one `Read` in the module.
pub trait Read {}
```
- [You may now use `Rc`, `Arc`, and `Pin` as method receivers][56805].
Compiler
--------
- [You can now set a linker flavor for `rustc` with the `-Clinker-flavor`
command line argument.][56351]
- [The minimum required LLVM version has been bumped to 6.0.][56642]
- [Added support for the PowerPC64 architecture on FreeBSD.][57615]
- [The `x86_64-fortanix-unknown-sgx` target support has been upgraded to
tier 2 support.][57130] Visit the [platform support][platform-support] page for
information on Rust's platform support.
- [Added support for the `thumbv7neon-linux-androideabi` and
`thumbv7neon-unknown-linux-gnueabihf` targets.][56947]
- [Added support for the `x86_64-unknown-uefi` target.][56769]
Libraries
---------
- [The methods `overflowing_{add, sub, mul, shl, shr}` are now `const`
functions for all numeric types.][57566]
- [The methods `rotate_left`, `rotate_right`, and `wrapping_{add, sub, mul, shl, shr}`
are now `const` functions for all numeric types.][57105]
- [The methods `is_positive` and `is_negative` are now `const` functions for
all signed numeric types.][57105]
- [The `get` method for all `NonZero` types is now `const`.][57167]
- [The methods `count_ones`, `count_zeros`, `leading_zeros`, `trailing_zeros`,
`swap_bytes`, `from_be`, `from_le`, `to_be`, `to_le` are now `const` for all
numeric types.][57234]
- [`Ipv4Addr::new` is now a `const` function][57234]
Stabilized APIs
---------------
- [`unix::FileExt::read_exact_at`]
- [`unix::FileExt::write_all_at`]
- [`Option::transpose`]
- [`Result::transpose`]
- [`convert::identity`]
- [`pin::Pin`]
- [`marker::Unpin`]
- [`marker::PhantomPinned`]
- [`Vec::resize_with`]
- [`VecDeque::resize_with`]
- [`Duration::as_millis`]
- [`Duration::as_micros`]
- [`Duration::as_nanos`]
Cargo
-----
- [You can now publish crates that require a feature flag to compile with
`cargo publish --features` or `cargo publish --all-features`.][cargo/6453]
- [Cargo should now rebuild a crate if a file was modified during the initial
build.][cargo/6484]
Compatibility Notes
-------------------
- The methods `str::{trim_left, trim_right, trim_left_matches, trim_right_matches}`
are now deprecated in the standard library, and their usage will now produce a warning.
Please use the `str::{trim_start, trim_end, trim_start_matches, trim_end_matches}`
methods instead.
- The `Error::cause` method has been deprecated in favor of `Error::source` which supports
downcasting.
- [Libtest no longer creates a new thread for each test when
`--test-threads=1`. It also runs the tests in deterministic order][56243]
[56243]: https://github.com/rust-lang/rust/pull/56243
[56303]: https://github.com/rust-lang/rust/pull/56303/
[56351]: https://github.com/rust-lang/rust/pull/56351/
[56362]: https://github.com/rust-lang/rust/pull/56362
[56642]: https://github.com/rust-lang/rust/pull/56642/
[56769]: https://github.com/rust-lang/rust/pull/56769/
[56805]: https://github.com/rust-lang/rust/pull/56805
[56947]: https://github.com/rust-lang/rust/pull/56947/
[57049]: https://github.com/rust-lang/rust/pull/57049/
[57067]: https://github.com/rust-lang/rust/pull/57067/
[57105]: https://github.com/rust-lang/rust/pull/57105
[57130]: https://github.com/rust-lang/rust/pull/57130/
[57167]: https://github.com/rust-lang/rust/pull/57167/
[57175]: https://github.com/rust-lang/rust/pull/57175/
[57234]: https://github.com/rust-lang/rust/pull/57234/
[57332]: https://github.com/rust-lang/rust/pull/57332/
[57465]: https://github.com/rust-lang/rust/pull/57465/
[57532]: https://github.com/rust-lang/rust/pull/57532/
[57535]: https://github.com/rust-lang/rust/pull/57535/
[57566]: https://github.com/rust-lang/rust/pull/57566/
[57615]: https://github.com/rust-lang/rust/pull/57615/
[cargo/6453]: https://github.com/rust-lang/cargo/pull/6453/
[cargo/6484]: https://github.com/rust-lang/cargo/pull/6484/
[`unix::FileExt::read_exact_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.read_exact_at
[`unix::FileExt::write_all_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.write_all_at
[`Option::transpose`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose
[`Result::transpose`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose
[`convert::identity`]: https://doc.rust-lang.org/std/convert/fn.identity.html
[`pin::Pin`]: https://doc.rust-lang.org/std/pin/struct.Pin.html
[`marker::Unpin`]: https://doc.rust-lang.org/stable/std/marker/trait.Unpin.html
[`marker::PhantomPinned`]: https://doc.rust-lang.org/nightly/std/marker/struct.PhantomPinned.html
[`Vec::resize_with`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.resize_with
[`VecDeque::resize_with`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.resize_with
[`Duration::as_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_millis
[`Duration::as_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_micros
[`Duration::as_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_nanos
[platform-support]: https://forge.rust-lang.org/platform-support.html
Version 1.32.0 (2019-01-17)
==========================
Language
--------
#### 2018 edition
- [You can now use the `?` operator in macro definitions.][56245] The `?`
operator allows you to specify zero or one repetitions similar to the `*` and
`+` operators.
- [Module paths with no leading keyword like `super`, `self`, or `crate`, will
now always resolve to the item (`enum`, `struct`, etc.) available in the
module if present, before resolving to a external crate or an item the prelude.][56759]
E.g.
```rust
enum Color { Red, Green, Blue }
use Color::*;
```
#### All editions
- [You can now match against `PhantomData` types.][55837]
- [You can now match against literals in macros with the `literal`
specifier.][56072] This will match against a literal of any type.
E.g. `1`, `'A'`, `"Hello World"`
- [Self can now be used as a constructor and pattern for unit and tuple structs.][56365] E.g.
```rust
struct Point(i32, i32);
impl Point {
pub fn new(x: i32, y: i32) -> Self {
Self(x, y)
}
pub fn is_origin(&self) -> bool {
match self {
Self(0, 0) => true,
_ => false,
}
}
}
```
- [Self can also now be used in type definitions.][56366] E.g.
```rust
enum List
where
Self: PartialOrd // can write `Self` instead of `List`
{
Nil,
Cons(T, Box) // likewise here
}
```
- [You can now mark traits with `#[must_use]`.][55663] This provides a warning if
a `impl Trait` or `dyn Trait` is returned and unused in the program.
Compiler
--------
- [The default allocator has changed from jemalloc to the default allocator on
your system.][55238] The compiler itself on Linux & macOS will still use
jemalloc, but programs compiled with it will use the system allocator.
- [Added the `aarch64-pc-windows-msvc` target.][55702]
Libraries
---------
- [`PathBuf` now implements `FromStr`.][55148]
- [`Box<[T]>` now implements `FromIterator`.][55843]
- [The `dbg!` macro has been stabilized.][56395] This macro enables you to
easily debug expressions in your rust program. E.g.
```rust
let a = 2;
let b = dbg!(a * 2) + 1;
// ^-- prints: [src/main.rs:4] a * 2 = 4
assert_eq!(b, 5);
```
The following APIs are now `const` functions and can be used in a
`const` context.
- [`Cell::as_ptr`]
- [`UnsafeCell::get`]
- [`char::is_ascii`]
- [`iter::empty`]
- [`ManuallyDrop::new`]
- [`ManuallyDrop::into_inner`]
- [`RangeInclusive::start`]
- [`RangeInclusive::end`]
- [`NonNull::as_ptr`]
- [`slice::as_ptr`]
- [`str::as_ptr`]
- [`Duration::as_secs`]
- [`Duration::subsec_millis`]
- [`Duration::subsec_micros`]
- [`Duration::subsec_nanos`]
- [`CStr::as_ptr`]
- [`Ipv4Addr::is_unspecified`]
- [`Ipv6Addr::new`]
- [`Ipv6Addr::octets`]
Stabilized APIs
---------------
- [`i8::to_be_bytes`]
- [`i8::to_le_bytes`]
- [`i8::to_ne_bytes`]
- [`i8::from_be_bytes`]
- [`i8::from_le_bytes`]
- [`i8::from_ne_bytes`]
- [`i16::to_be_bytes`]
- [`i16::to_le_bytes`]
- [`i16::to_ne_bytes`]
- [`i16::from_be_bytes`]
- [`i16::from_le_bytes`]
- [`i16::from_ne_bytes`]
- [`i32::to_be_bytes`]
- [`i32::to_le_bytes`]
- [`i32::to_ne_bytes`]
- [`i32::from_be_bytes`]
- [`i32::from_le_bytes`]
- [`i32::from_ne_bytes`]
- [`i64::to_be_bytes`]
- [`i64::to_le_bytes`]
- [`i64::to_ne_bytes`]
- [`i64::from_be_bytes`]
- [`i64::from_le_bytes`]
- [`i64::from_ne_bytes`]
- [`i128::to_be_bytes`]
- [`i128::to_le_bytes`]
- [`i128::to_ne_bytes`]
- [`i128::from_be_bytes`]
- [`i128::from_le_bytes`]
- [`i128::from_ne_bytes`]
- [`isize::to_be_bytes`]
- [`isize::to_le_bytes`]
- [`isize::to_ne_bytes`]
- [`isize::from_be_bytes`]
- [`isize::from_le_bytes`]
- [`isize::from_ne_bytes`]
- [`u8::to_be_bytes`]
- [`u8::to_le_bytes`]
- [`u8::to_ne_bytes`]
- [`u8::from_be_bytes`]
- [`u8::from_le_bytes`]
- [`u8::from_ne_bytes`]
- [`u16::to_be_bytes`]
- [`u16::to_le_bytes`]
- [`u16::to_ne_bytes`]
- [`u16::from_be_bytes`]
- [`u16::from_le_bytes`]
- [`u16::from_ne_bytes`]
- [`u32::to_be_bytes`]
- [`u32::to_le_bytes`]
- [`u32::to_ne_bytes`]
- [`u32::from_be_bytes`]
- [`u32::from_le_bytes`]
- [`u32::from_ne_bytes`]
- [`u64::to_be_bytes`]
- [`u64::to_le_bytes`]
- [`u64::to_ne_bytes`]
- [`u64::from_be_bytes`]
- [`u64::from_le_bytes`]
- [`u64::from_ne_bytes`]
- [`u128::to_be_bytes`]
- [`u128::to_le_bytes`]
- [`u128::to_ne_bytes`]
- [`u128::from_be_bytes`]
- [`u128::from_le_bytes`]
- [`u128::from_ne_bytes`]
- [`usize::to_be_bytes`]
- [`usize::to_le_bytes`]
- [`usize::to_ne_bytes`]
- [`usize::from_be_bytes`]
- [`usize::from_le_bytes`]
- [`usize::from_ne_bytes`]
Cargo
-----
- [You can now run `cargo c` as an alias for `cargo check`.][cargo/6218]
- [Usernames are now allowed in alt registry URLs.][cargo/6242]
Misc
----
- [`libproc_macro` has been added to the `rust-src` distribution.][55280]
Compatibility Notes
-------------------
- [The argument types for AVX's
`_mm256_stream_si256`, `_mm256_stream_pd`, `_mm256_stream_ps`][55610] have
been changed from `*const` to `*mut` as the previous implementation
was unsound.
[55148]: https://github.com/rust-lang/rust/pull/55148/
[55238]: https://github.com/rust-lang/rust/pull/55238/
[55280]: https://github.com/rust-lang/rust/pull/55280/
[55610]: https://github.com/rust-lang/rust/pull/55610/
[55663]: https://github.com/rust-lang/rust/pull/55663/
[55702]: https://github.com/rust-lang/rust/pull/55702/
[55837]: https://github.com/rust-lang/rust/pull/55837/
[55843]: https://github.com/rust-lang/rust/pull/55843/
[56072]: https://github.com/rust-lang/rust/pull/56072/
[56245]: https://github.com/rust-lang/rust/pull/56245/
[56365]: https://github.com/rust-lang/rust/pull/56365/
[56366]: https://github.com/rust-lang/rust/pull/56366/
[56395]: https://github.com/rust-lang/rust/pull/56395/
[56759]: https://github.com/rust-lang/rust/pull/56759/
[cargo/6218]: https://github.com/rust-lang/cargo/pull/6218/
[cargo/6242]: https://github.com/rust-lang/cargo/pull/6242/
[`CStr::as_ptr`]: https://doc.rust-lang.org/std/ffi/struct.CStr.html#method.as_ptr
[`Cell::as_ptr`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_ptr
[`Duration::as_secs`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs
[`Duration::subsec_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_micros
[`Duration::subsec_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_millis
[`Duration::subsec_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_nanos
[`Ipv4Addr::is_unspecified`]: https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#method.is_unspecified
[`Ipv6Addr::new`]: https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.new
[`Ipv6Addr::octets`]: https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.octets
[`ManuallyDrop::into_inner`]: https://doc.rust-lang.org/std/mem/struct.ManuallyDrop.html#method.into_inner
[`ManuallyDrop::new`]: https://doc.rust-lang.org/std/mem/struct.ManuallyDrop.html#method.new
[`NonNull::as_ptr`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html#method.as_ptr
[`RangeInclusive::end`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.end
[`RangeInclusive::start`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.start
[`UnsafeCell::get`]: https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get
[`slice::as_ptr`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr
[`char::is_ascii`]: https://doc.rust-lang.org/std/primitive.char.html#method.is_ascii
[`i128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_be_bytes
[`i128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_le_bytes
[`i128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_ne_bytes
[`i128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_be_bytes
[`i128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_le_bytes
[`i128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_ne_bytes
[`i16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_be_bytes
[`i16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_le_bytes
[`i16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_ne_bytes
[`i16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_be_bytes
[`i16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_le_bytes
[`i16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_ne_bytes
[`i32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_be_bytes
[`i32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_le_bytes
[`i32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_ne_bytes
[`i32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_be_bytes
[`i32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_le_bytes
[`i32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_ne_bytes
[`i64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_be_bytes
[`i64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_le_bytes
[`i64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_ne_bytes
[`i64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_be_bytes
[`i64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_le_bytes
[`i64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_ne_bytes
[`i8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_be_bytes
[`i8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_le_bytes
[`i8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_ne_bytes
[`i8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_be_bytes
[`i8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_le_bytes
[`i8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_ne_bytes
[`isize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_be_bytes
[`isize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_le_bytes
[`isize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_ne_bytes
[`isize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_be_bytes
[`isize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_le_bytes
[`isize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_ne_bytes
[`iter::empty`]: https://doc.rust-lang.org/std/iter/fn.empty.html
[`str::as_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_ptr
[`u128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_be_bytes
[`u128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_le_bytes
[`u128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_ne_bytes
[`u128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_be_bytes
[`u128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_le_bytes
[`u128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_ne_bytes
[`u16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_be_bytes
[`u16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_le_bytes
[`u16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_ne_bytes
[`u16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_be_bytes
[`u16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_le_bytes
[`u16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_ne_bytes
[`u32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_be_bytes
[`u32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_le_bytes
[`u32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_ne_bytes
[`u32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_be_bytes
[`u32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_le_bytes
[`u32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_ne_bytes
[`u64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_be_bytes
[`u64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_le_bytes
[`u64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_ne_bytes
[`u64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_be_bytes
[`u64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_le_bytes
[`u64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_ne_bytes
[`u8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_be_bytes
[`u8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_le_bytes
[`u8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_ne_bytes
[`u8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_be_bytes
[`u8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_le_bytes
[`u8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_ne_bytes
[`usize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_be_bytes
[`usize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_le_bytes
[`usize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_ne_bytes
[`usize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_be_bytes
[`usize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_le_bytes
[`usize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_ne_bytes
Version 1.31.1 (2018-12-20)
===========================
- [Fix Rust failing to build on `powerpc-unknown-netbsd`][56562]
- [Fix broken go-to-definition in RLS][rls/1171]
- [Fix infinite loop on hover in RLS][rls/1170]
[56562]: https://github.com/rust-lang/rust/pull/56562
[rls/1171]: https://github.com/rust-lang/rls/issues/1171
[rls/1170]: https://github.com/rust-lang/rls/pull/1170
Version 1.31.0 (2018-12-06)
==========================
Language
--------
- 🎉 [This version marks the release of the 2018 edition of Rust.][54057] 🎉
- [New lifetime elision rules now allow for eliding lifetimes in functions and
impl headers.][54778] E.g. `impl<'a> Reader for BufReader<'a> {}` can now be
`impl Reader for BufReader<'_> {}`. Lifetimes are still required to be defined
in structs.
- [You can now define and use `const` functions.][54835] These are currently
a strict minimal subset of the [const fn RFC][RFC-911]. Refer to the
[language reference][const-reference] for what exactly is available.
- [You can now use tool lints, which allow you to scope lints from external
tools using attributes.][54870] E.g. `#[allow(clippy::filter_map)]`.
- [`#[no_mangle]` and `#[export_name]` attributes can now be located anywhere in
a crate, not just in exported functions.][54451]
- [You can now use parentheses in pattern matches.][54497]
Compiler
--------
- [Updated musl to 1.1.20][54430]
Libraries
---------
- [You can now convert `num::NonZero*` types to their raw equivalents using the
`From` trait.][54240] E.g. `u8` now implements `From`.
- [You can now convert a `&Option` into `Option<&T>` and `&mut Option`
into `Option<&mut T>` using the `From` trait.][53218]
- [You can now multiply (`*`) a `time::Duration` by a `u32`.][52813]
Stabilized APIs
---------------
- [`slice::align_to`]
- [`slice::align_to_mut`]
- [`slice::chunks_exact`]
- [`slice::chunks_exact_mut`]
- [`slice::rchunks`]
- [`slice::rchunks_mut`]
- [`slice::rchunks_exact`]
- [`slice::rchunks_exact_mut`]
- [`Option::replace`]
Cargo
-----
- [Cargo will now download crates in parallel using HTTP/2.][cargo/6005]
- [You can now rename packages in your Cargo.toml][cargo/6319] We have a guide
on [how to use the `package` key in your dependencies.][cargo-rename-reference]
[52813]: https://github.com/rust-lang/rust/pull/52813/
[53218]: https://github.com/rust-lang/rust/pull/53218/
[54057]: https://github.com/rust-lang/rust/pull/54057/
[54240]: https://github.com/rust-lang/rust/pull/54240/
[54430]: https://github.com/rust-lang/rust/pull/54430/
[54451]: https://github.com/rust-lang/rust/pull/54451/
[54497]: https://github.com/rust-lang/rust/pull/54497/
[54778]: https://github.com/rust-lang/rust/pull/54778/
[54835]: https://github.com/rust-lang/rust/pull/54835/
[54870]: https://github.com/rust-lang/rust/pull/54870/
[RFC-911]: https://github.com/rust-lang/rfcs/pull/911
[`Option::replace`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.replace
[`slice::align_to_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.align_to_mut
[`slice::align_to`]: https://doc.rust-lang.org/std/primitive.slice.html#method.align_to
[`slice::chunks_exact_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.chunks_exact_mut
[`slice::chunks_exact`]: https://doc.rust-lang.org/std/primitive.slice.html#method.chunks_exact
[`slice::rchunks_exact_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_mut
[`slice::rchunks_exact`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_exact
[`slice::rchunks_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks_mut
[`slice::rchunks`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rchunks
[cargo/6005]: https://github.com/rust-lang/cargo/pull/6005/
[cargo/6319]: https://github.com/rust-lang/cargo/pull/6319/
[cargo-rename-reference]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#renaming-dependencies-in-cargotoml
[const-reference]: https://doc.rust-lang.org/reference/items/functions.html#const-functions
Version 1.30.1 (2018-11-08)
===========================
- [Fixed overflow ICE in rustdoc][54199]
- [Cap Cargo progress bar width at 60 in MSYS terminals][cargo/6122]
[54199]: https://github.com/rust-lang/rust/pull/54199
[cargo/6122]: https://github.com/rust-lang/cargo/pull/6122
Version 1.30.0 (2018-10-25)
==========================
Language
--------
- [Procedural macros are now available.][52081] These kinds of macros allow for
more powerful code generation. There is a [new chapter available][proc-macros]
in the Rust Programming Language book that goes further in depth.
- [You can now use keywords as identifiers using the raw identifiers
syntax (`r#`),][53236] e.g. `let r#for = true;`
- [Using anonymous parameters in traits is now deprecated with a warning and
will be a hard error in the 2018 edition.][53272]
- [You can now use `crate` in paths.][54404] This allows you to refer to the
crate root in the path, e.g. `use crate::foo;` refers to `foo` in `src/lib.rs`.
- [Using a external crate no longer requires being prefixed with `::`.][54404]
Previously, using a external crate in a module without a use statement
required `let json = ::serde_json::from_str(foo);` but can now be written
as `let json = serde_json::from_str(foo);`.
- [You can now apply the `#[used]` attribute to static items to prevent the
compiler from optimising them away, even if they appear to be unused,][51363]
e.g. `#[used] static FOO: u32 = 1;`
- [You can now import and reexport macros from other crates with the `use`
syntax.][50911] Macros exported with `#[macro_export]` are now placed into
the root module of the crate. If your macro relies on calling other local
macros, it is recommended to export with the
`#[macro_export(local_inner_macros)]` attribute so users won't have to import
those macros.
- [You can now catch visibility keywords (e.g. `pub`, `pub(crate)`) in macros
using the `vis` specifier.][53370]
- [Non-macro attributes now allow all forms of literals, not just
strings.][53044] Previously, you would write `#[attr("true")]`, and you can now
write `#[attr(true)]`.
- [You can now specify a function to handle a panic in the Rust runtime with the
`#[panic_handler]` attribute.][51366]
Compiler
--------
- [Added the `riscv32imc-unknown-none-elf` target.][53822]
- [Added the `aarch64-unknown-netbsd` target][53165]
- [Upgraded to LLVM 8.][53611]
Libraries
---------
- [`ManuallyDrop` now allows the inner type to be unsized.][53033]
Stabilized APIs
---------------
- [`Ipv4Addr::BROADCAST`]
- [`Ipv4Addr::LOCALHOST`]
- [`Ipv4Addr::UNSPECIFIED`]
- [`Ipv6Addr::LOCALHOST`]
- [`Ipv6Addr::UNSPECIFIED`]
- [`Iterator::find_map`]
The following methods are replacement methods for `trim_left`, `trim_right`,
`trim_left_matches`, and `trim_right_matches`, which will be deprecated
in 1.33.0:
- [`str::trim_end_matches`]
- [`str::trim_end`]
- [`str::trim_start_matches`]
- [`str::trim_start`]
Cargo
----
- [`cargo run` doesn't require specifying a package in workspaces.][cargo/5877]
- [`cargo doc` now supports `--message-format=json`.][cargo/5878] This is
equivalent to calling `rustdoc --error-format=json`.
- [Cargo will now provide a progress bar for builds.][cargo/5995]
Misc
----
- [`rustdoc` allows you to specify what edition to treat your code as with the
`--edition` option.][54057]
- [`rustdoc` now has the `--color` (specify whether to output color) and
`--error-format` (specify error format, e.g. `json`) options.][53003]
- [We now distribute a `rust-gdbgui` script that invokes `gdbgui` with Rust
debug symbols.][53774]
- [Attributes from Rust tools such as `rustfmt` or `clippy` are now
available,][53459] e.g. `#[rustfmt::skip]` will skip formatting the next item.
[50911]: https://github.com/rust-lang/rust/pull/50911/
[51363]: https://github.com/rust-lang/rust/pull/51363/
[51366]: https://github.com/rust-lang/rust/pull/51366/
[52081]: https://github.com/rust-lang/rust/pull/52081/
[53003]: https://github.com/rust-lang/rust/pull/53003/
[53033]: https://github.com/rust-lang/rust/pull/53033/
[53044]: https://github.com/rust-lang/rust/pull/53044/
[53165]: https://github.com/rust-lang/rust/pull/53165/
[53611]: https://github.com/rust-lang/rust/pull/53611/
[53236]: https://github.com/rust-lang/rust/pull/53236/
[53272]: https://github.com/rust-lang/rust/pull/53272/
[53370]: https://github.com/rust-lang/rust/pull/53370/
[53459]: https://github.com/rust-lang/rust/pull/53459/
[53774]: https://github.com/rust-lang/rust/pull/53774/
[53822]: https://github.com/rust-lang/rust/pull/53822/
[54057]: https://github.com/rust-lang/rust/pull/54057/
[54404]: https://github.com/rust-lang/rust/pull/54404/
[cargo/5877]: https://github.com/rust-lang/cargo/pull/5877/
[cargo/5878]: https://github.com/rust-lang/cargo/pull/5878/
[cargo/5995]: https://github.com/rust-lang/cargo/pull/5995/
[proc-macros]: https://doc.rust-lang.org/nightly/book/2018-edition/ch19-06-macros.html
[`Ipv4Addr::BROADCAST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.BROADCAST
[`Ipv4Addr::LOCALHOST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.LOCALHOST
[`Ipv4Addr::UNSPECIFIED`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.UNSPECIFIED
[`Ipv6Addr::LOCALHOST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#associatedconstant.LOCALHOST
[`Ipv6Addr::UNSPECIFIED`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv6Addr.html#associatedconstant.UNSPECIFIED
[`Iterator::find_map`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.find_map
[`str::trim_end_matches`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_end_matches
[`str::trim_end`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_end
[`str::trim_start_matches`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_start_matches
[`str::trim_start`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim_start
Version 1.29.2 (2018-10-11)
===========================
- [Workaround for an aliasing-related LLVM bug, which caused miscompilation.][54639]
- The `rls-preview` component on the windows-gnu targets has been restored.
[54639]: https://github.com/rust-lang/rust/pull/54639
Version 1.29.1 (2018-09-25)
===========================
Security Notes
--------------
- The standard library's `str::repeat` function contained an out of bounds write
caused by an integer overflow. This has been fixed by deterministically
panicking when an overflow happens.
Thank you to Scott McMurray for responsibly disclosing this vulnerability to
us.
Version 1.29.0 (2018-09-13)
==========================
Compiler
--------
- [Bumped minimum LLVM version to 5.0.][51899]
- [Added `powerpc64le-unknown-linux-musl` target.][51619]
- [Added `aarch64-unknown-hermit` and `x86_64-unknown-hermit` targets.][52861]
- [Upgraded to LLVM 7.][51966]
Libraries
---------
- [`Once::call_once` no longer requires `Once` to be `'static`.][52239]
- [`BuildHasherDefault` now implements `PartialEq` and `Eq`.][52402]
- [`Box`, `Box`, and `Box` now implement `Clone`.][51912]
- [Implemented `PartialEq<&str>` for `OsString` and `PartialEq`
for `&str`.][51178]
- [`Cell` now allows `T` to be unsized.][50494]
- [`SocketAddr` is now stable on Redox.][52656]
Stabilized APIs
---------------
- [`Arc::downcast`]
- [`Iterator::flatten`]
- [`Rc::downcast`]
Cargo
-----
- [Cargo can silently fix some bad lockfiles.][cargo/5831] You can use
`--locked` to disable this behavior.
- [`cargo-install` will now allow you to cross compile an install
using `--target`.][cargo/5614]
- [Added the `cargo-fix` subcommand to automatically move project code from
2015 edition to 2018.][cargo/5723]
- [`cargo doc` can now optionally document private types using the
`--document-private-items` flag.][cargo/5543]
Misc
----
- [`rustdoc` now has the `--cap-lints` option which demotes all lints above
the specified level to that level.][52354] For example `--cap-lints warn`
will demote `deny` and `forbid` lints to `warn`.
- [`rustc` and `rustdoc` will now have the exit code of `1` if compilation
fails and `101` if there is a panic.][52197]
- [A preview of clippy has been made available through rustup.][51122]
You can install the preview with `rustup component add clippy-preview`.
Compatibility Notes
-------------------
- [`str::{slice_unchecked, slice_unchecked_mut}` are now deprecated.][51807]
Use `str::get_unchecked(begin..end)` instead.
- [`std::env::home_dir` is now deprecated for its unintuitive behavior.][51656]
Consider using the `home_dir` function from
https://crates.io/crates/dirs instead.
- [`rustc` will no longer silently ignore invalid data in target spec.][52330]
- [`cfg` attributes and `--cfg` command line flags are now more
strictly validated.][53893]
[53893]: https://github.com/rust-lang/rust/pull/53893/
[52861]: https://github.com/rust-lang/rust/pull/52861/
[51966]: https://github.com/rust-lang/rust/pull/51966/
[52656]: https://github.com/rust-lang/rust/pull/52656/
[52239]: https://github.com/rust-lang/rust/pull/52239/
[52330]: https://github.com/rust-lang/rust/pull/52330/
[52354]: https://github.com/rust-lang/rust/pull/52354/
[52402]: https://github.com/rust-lang/rust/pull/52402/
[52197]: https://github.com/rust-lang/rust/pull/52197/
[51807]: https://github.com/rust-lang/rust/pull/51807/
[51899]: https://github.com/rust-lang/rust/pull/51899/
[51912]: https://github.com/rust-lang/rust/pull/51912/
[51619]: https://github.com/rust-lang/rust/pull/51619/
[51656]: https://github.com/rust-lang/rust/pull/51656/
[51178]: https://github.com/rust-lang/rust/pull/51178/
[51122]: https://github.com/rust-lang/rust/pull/51122
[50494]: https://github.com/rust-lang/rust/pull/50494/
[cargo/5543]: https://github.com/rust-lang/cargo/pull/5543
[cargo/5614]: https://github.com/rust-lang/cargo/pull/5614/
[cargo/5723]: https://github.com/rust-lang/cargo/pull/5723/
[cargo/5831]: https://github.com/rust-lang/cargo/pull/5831/
[`Arc::downcast`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.downcast
[`Iterator::flatten`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.flatten
[`Rc::downcast`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.downcast
Version 1.28.0 (2018-08-02)
===========================
Language
--------
- [The `#[repr(transparent)]` attribute is now stable.][51562] This attribute
allows a Rust newtype wrapper (`struct NewType(T);`) to be represented as
the inner type across Foreign Function Interface (FFI) boundaries.
- [The keywords `pure`, `sizeof`, `alignof`, and `offsetof` have been unreserved
and can now be used as identifiers.][51196]
- [The `GlobalAlloc` trait and `#[global_allocator]` attribute are now
stable.][51241] This will allow users to specify a global allocator for
their program.
- [Unit test functions marked with the `#[test]` attribute can now return
`Result<(), E: Debug>` in addition to `()`.][51298]
- [The `lifetime` specifier for `macro_rules!` is now stable.][50385] This
allows macros to easily target lifetimes.
Compiler
--------
- [The `s` and `z` optimisation levels are now stable.][50265] These optimisations
prioritise making smaller binary sizes. `z` is the same as `s` with the
exception that it does not vectorise loops, which typically results in an even
smaller binary.
- [The short error format is now stable.][49546] Specified with
`--error-format=short` this option will provide a more compressed output of
rust error messages.
- [Added a lint warning when you have duplicated `macro_export`s.][50143]
- [Reduced the number of allocations in the macro parser.][50855] This can
improve compile times of macro heavy crates on average by 5%.
Libraries
---------
- [Implemented `Default` for `&mut str`.][51306]
- [Implemented `From` for all integer and unsigned number types.][50554]
- [Implemented `Extend` for `()`.][50234]
- [The `Debug` implementation of `time::Duration` should now be more easily
human readable.][50364] Previously a `Duration` of one second would printed as
`Duration { secs: 1, nanos: 0 }` and will now be printed as `1s`.
- [Implemented `From<&String>` for `Cow`, `From<&Vec>` for `Cow<[T]>`,
`From>` for `CString`, `From, From, From<&CString>`
for `Cow`, `From, From, From<&OsString>` for
`Cow`, `From<&PathBuf>` for `Cow`, and `From>`
for `PathBuf`.][50170]
- [Implemented `Shl` and `Shr` for `Wrapping`
and `Wrapping`.][50465]
- [`DirEntry::metadata` now uses `fstatat` instead of `lstat` when
possible.][51050] This can provide up to a 40% speed increase.
- [Improved error messages when using `format!`.][50610]
Stabilized APIs
---------------
- [`Iterator::step_by`]
- [`Path::ancestors`]
- [`SystemTime::UNIX_EPOCH`]
- [`alloc::GlobalAlloc`]
- [`alloc::Layout`]
- [`alloc::LayoutErr`]
- [`alloc::System`]
- [`alloc::alloc`]
- [`alloc::alloc_zeroed`]
- [`alloc::dealloc`]
- [`alloc::realloc`]
- [`alloc::handle_alloc_error`]
- [`btree_map::Entry::or_default`]
- [`fmt::Alignment`]
- [`hash_map::Entry::or_default`]
- [`iter::repeat_with`]
- [`num::NonZeroUsize`]
- [`num::NonZeroU128`]
- [`num::NonZeroU16`]
- [`num::NonZeroU32`]
- [`num::NonZeroU64`]
- [`num::NonZeroU8`]
- [`ops::RangeBounds`]
- [`slice::SliceIndex`]
- [`slice::from_mut`]
- [`slice::from_ref`]
- [`{Any + Send + Sync}::downcast_mut`]
- [`{Any + Send + Sync}::downcast_ref`]
- [`{Any + Send + Sync}::is`]
Cargo
-----
- [Cargo will now no longer allow you to publish crates with build scripts that
modify the `src` directory.][cargo/5584] The `src` directory in a crate should be
considered to be immutable.
Misc
----
- [The `suggestion_applicability` field in `rustc`'s json output is now
stable.][50486] This will allow dev tools to check whether a code suggestion
would apply to them.
Compatibility Notes
-------------------
- [Rust will consider trait objects with duplicated constraints to be the same
type as without the duplicated constraint.][51276] For example the below code will
now fail to compile.
```rust
trait Trait {}
impl Trait + Send {
fn test(&self) { println!("one"); } //~ ERROR duplicate definitions with name `test`
}
impl Trait + Send + Send {
fn test(&self) { println!("two"); }
}
```
[49546]: https://github.com/rust-lang/rust/pull/49546/
[50143]: https://github.com/rust-lang/rust/pull/50143/
[50170]: https://github.com/rust-lang/rust/pull/50170/
[50234]: https://github.com/rust-lang/rust/pull/50234/
[50265]: https://github.com/rust-lang/rust/pull/50265/
[50364]: https://github.com/rust-lang/rust/pull/50364/
[50385]: https://github.com/rust-lang/rust/pull/50385/
[50465]: https://github.com/rust-lang/rust/pull/50465/
[50486]: https://github.com/rust-lang/rust/pull/50486/
[50554]: https://github.com/rust-lang/rust/pull/50554/
[50610]: https://github.com/rust-lang/rust/pull/50610/
[50855]: https://github.com/rust-lang/rust/pull/50855/
[51050]: https://github.com/rust-lang/rust/pull/51050/
[51196]: https://github.com/rust-lang/rust/pull/51196/
[51241]: https://github.com/rust-lang/rust/pull/51241/
[51276]: https://github.com/rust-lang/rust/pull/51276/
[51298]: https://github.com/rust-lang/rust/pull/51298/
[51306]: https://github.com/rust-lang/rust/pull/51306/
[51562]: https://github.com/rust-lang/rust/pull/51562/
[cargo/5584]: https://github.com/rust-lang/cargo/pull/5584/
[`Iterator::step_by`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.step_by
[`Path::ancestors`]: https://doc.rust-lang.org/std/path/struct.Path.html#method.ancestors
[`SystemTime::UNIX_EPOCH`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#associatedconstant.UNIX_EPOCH
[`alloc::GlobalAlloc`]: https://doc.rust-lang.org/std/alloc/trait.GlobalAlloc.html
[`alloc::Layout`]: https://doc.rust-lang.org/std/alloc/struct.Layout.html
[`alloc::LayoutErr`]: https://doc.rust-lang.org/std/alloc/struct.LayoutErr.html
[`alloc::System`]: https://doc.rust-lang.org/std/alloc/struct.System.html
[`alloc::alloc`]: https://doc.rust-lang.org/std/alloc/fn.alloc.html
[`alloc::alloc_zeroed`]: https://doc.rust-lang.org/std/alloc/fn.alloc_zeroed.html
[`alloc::dealloc`]: https://doc.rust-lang.org/std/alloc/fn.dealloc.html
[`alloc::realloc`]: https://doc.rust-lang.org/std/alloc/fn.realloc.html
[`alloc::handle_alloc_error`]: https://doc.rust-lang.org/std/alloc/fn.handle_alloc_error.html
[`btree_map::Entry::or_default`]: https://doc.rust-lang.org/std/collections/btree_map/enum.Entry.html#method.or_default
[`fmt::Alignment`]: https://doc.rust-lang.org/std/fmt/enum.Alignment.html
[`hash_map::Entry::or_default`]: https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html#method.or_default
[`iter::repeat_with`]: https://doc.rust-lang.org/std/iter/fn.repeat_with.html
[`num::NonZeroUsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroUsize.html
[`num::NonZeroU128`]: https://doc.rust-lang.org/std/num/struct.NonZeroU128.html
[`num::NonZeroU16`]: https://doc.rust-lang.org/std/num/struct.NonZeroU16.html
[`num::NonZeroU32`]: https://doc.rust-lang.org/std/num/struct.NonZeroU32.html
[`num::NonZeroU64`]: https://doc.rust-lang.org/std/num/struct.NonZeroU64.html
[`num::NonZeroU8`]: https://doc.rust-lang.org/std/num/struct.NonZeroU8.html
[`ops::RangeBounds`]: https://doc.rust-lang.org/std/ops/trait.RangeBounds.html
[`slice::SliceIndex`]: https://doc.rust-lang.org/std/slice/trait.SliceIndex.html
[`slice::from_mut`]: https://doc.rust-lang.org/std/slice/fn.from_mut.html
[`slice::from_ref`]: https://doc.rust-lang.org/std/slice/fn.from_ref.html
[`{Any + Send + Sync}::downcast_mut`]: https://doc.rust-lang.org/std/any/trait.Any.html#method.downcast_mut-2
[`{Any + Send + Sync}::downcast_ref`]: https://doc.rust-lang.org/std/any/trait.Any.html#method.downcast_ref-2
[`{Any + Send + Sync}::is`]: https://doc.rust-lang.org/std/any/trait.Any.html#method.is-2
Version 1.27.2 (2018-07-20)
===========================
Compatibility Notes
-------------------
- The borrow checker was fixed to avoid potential unsoundness when using
match ergonomics: [#52213][52213].
[52213]: https://github.com/rust-lang/rust/issues/52213
Version 1.27.1 (2018-07-10)
===========================
Security Notes
--------------
- rustdoc would execute plugins in the /tmp/rustdoc/plugins directory
when running, which enabled executing code as some other user on a
given machine. This release fixes that vulnerability; you can read
more about this on the [blog][rustdoc-sec]. The associated CVE is [CVE-2018-1000622].
Thank you to Red Hat for responsibly disclosing this vulnerability to us.
Compatibility Notes
-------------------
- The borrow checker was fixed to avoid an additional potential unsoundness when using
match ergonomics: [#51415][51415], [#49534][49534].
[51415]: https://github.com/rust-lang/rust/issues/51415
[49534]: https://github.com/rust-lang/rust/issues/49534
[rustdoc-sec]: https://blog.rust-lang.org/2018/07/06/security-advisory-for-rustdoc.html
[CVE-2018-1000622]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=%20CVE-2018-1000622
Version 1.27.0 (2018-06-21)
==========================
Language
--------
- [Removed 'proc' from the reserved keywords list.][49699] This allows `proc` to
be used as an identifier.
- [The dyn syntax is now available.][49968] This syntax is equivalent to the
bare `Trait` syntax, and should make it clearer when being used in tandem with
`impl Trait` because it is equivalent to the following syntax:
`&Trait == &dyn Trait`, `&mut Trait == &mut dyn Trait`, and
`Box == Box`.
- [Attributes on generic parameters such as types and lifetimes are
now stable.][48851] e.g.
`fn foo<#[lifetime_attr] 'a, #[type_attr] T: 'a>() {}`
- [The `#[must_use]` attribute can now also be used on functions as well as
types.][48925] It provides a lint that by default warns users when the
value returned by a function has not been used.
Compiler
--------
- [Added the `armv5te-unknown-linux-musleabi` target.][50423]
Libraries
---------
- [SIMD (Single Instruction Multiple Data) on x86/x86_64 is now stable.][49664]
This includes [`arch::x86`] & [`arch::x86_64`] modules which contain
SIMD intrinsics, a new macro called `is_x86_feature_detected!`, the
`#[target_feature(enable="")]` attribute, and adding `target_feature = ""` to
the `cfg` attribute.
- [A lot of methods for `[u8]`, `f32`, and `f64` previously only available in
std are now available in core.][49896]
- [The generic `Rhs` type parameter on `ops::{Shl, ShlAssign, Shr}` now defaults
to `Self`.][49630]
- [`std::str::replace` now has the `#[must_use]` attribute][50177] to clarify
that the operation isn't done in place.
- [`Clone::clone`, `Iterator::collect`, and `ToOwned::to_owned` now have
the `#[must_use]` attribute][49533] to warn about unused potentially
expensive allocations.
Stabilized APIs
---------------
- [`DoubleEndedIterator::rfind`]
- [`DoubleEndedIterator::rfold`]
- [`DoubleEndedIterator::try_rfold`]
- [`Duration::from_micros`]
- [`Duration::from_nanos`]
- [`Duration::subsec_micros`]
- [`Duration::subsec_millis`]
- [`HashMap::remove_entry`]
- [`Iterator::try_fold`]
- [`Iterator::try_for_each`]
- [`NonNull::cast`]
- [`Option::filter`]
- [`String::replace_range`]
- [`Take::set_limit`]
- [`hint::unreachable_unchecked`]
- [`os::unix::process::parent_id`]
- [`ptr::swap_nonoverlapping`]
- [`slice::rsplit_mut`]
- [`slice::rsplit`]
- [`slice::swap_with_slice`]
Cargo
-----
- [`cargo-metadata` now includes `authors`, `categories`, `keywords`,
`readme`, and `repository` fields.][cargo/5386]
- [`cargo-metadata` now includes a package's `metadata` table.][cargo/5360]
- [Added the `--target-dir` optional argument.][cargo/5393] This allows you to specify
a different directory than `target` for placing compilation artifacts.
- [Cargo will be adding automatic target inference for binaries, benchmarks,
examples, and tests in the Rust 2018 edition.][cargo/5335] If your project specifies
specific targets, e.g. using `[[bin]]`, and have other binaries in locations
where cargo would infer a binary, Cargo will produce a warning. You can
disable this feature ahead of time by setting any of the following to false:
`autobins`, `autobenches`, `autoexamples`, `autotests`.
- [Cargo will now cache compiler information.][cargo/5359] This can be disabled by
setting `CARGO_CACHE_RUSTC_INFO=0` in your environment.
Misc
----
- [Added “The Rustc book” into the official documentation.][49707]
[“The Rustc book”] documents and teaches how to use the rustc compiler.
- [All books available on `doc.rust-lang.org` are now searchable.][49623]
Compatibility Notes
-------------------
- [Calling a `CharExt` or `StrExt` method directly on core will no longer
work.][49896] e.g. `::core::prelude::v1::StrExt::is_empty("")` will not
compile, `"".is_empty()` will still compile.
- [`Debug` output on `atomic::{AtomicBool, AtomicIsize, AtomicPtr, AtomicUsize}`
will only print the inner type.][48553] E.g.
`print!("{:?}", AtomicBool::new(true))` will print `true`,
not `AtomicBool(true)`.
- [The maximum number for `repr(align(N))` is now 2²⁹.][50378] Previously you
could enter higher numbers but they were not supported by LLVM. Up to 512MB
alignment should cover all use cases.
- The `.description()` method on the `std::error::Error` trait
[has been soft-deprecated][50163]. It is no longer required to implement it.
[48553]: https://github.com/rust-lang/rust/pull/48553/
[48851]: https://github.com/rust-lang/rust/pull/48851/
[48925]: https://github.com/rust-lang/rust/pull/48925/
[49533]: https://github.com/rust-lang/rust/pull/49533/
[49623]: https://github.com/rust-lang/rust/pull/49623/
[49630]: https://github.com/rust-lang/rust/pull/49630/
[49664]: https://github.com/rust-lang/rust/pull/49664/
[49699]: https://github.com/rust-lang/rust/pull/49699/
[49707]: https://github.com/rust-lang/rust/pull/49707/
[49896]: https://github.com/rust-lang/rust/pull/49896/
[49968]: https://github.com/rust-lang/rust/pull/49968/
[50163]: https://github.com/rust-lang/rust/pull/50163
[50177]: https://github.com/rust-lang/rust/pull/50177/
[50378]: https://github.com/rust-lang/rust/pull/50378/
[50423]: https://github.com/rust-lang/rust/pull/50423/
[cargo/5335]: https://github.com/rust-lang/cargo/pull/5335/
[cargo/5359]: https://github.com/rust-lang/cargo/pull/5359/
[cargo/5360]: https://github.com/rust-lang/cargo/pull/5360/
[cargo/5386]: https://github.com/rust-lang/cargo/pull/5386/
[cargo/5393]: https://github.com/rust-lang/cargo/pull/5393/
[`DoubleEndedIterator::rfind`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.rfind
[`DoubleEndedIterator::rfold`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.rfold
[`DoubleEndedIterator::try_rfold`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.try_rfold
[`Duration::from_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_micros
[`Duration::from_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.from_nanos
[`Duration::subsec_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_micros
[`Duration::subsec_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_millis
[`HashMap::remove_entry`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.remove_entry
[`Iterator::try_fold`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.try_fold
[`Iterator::try_for_each`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.try_for_each
[`NonNull::cast`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html#method.cast
[`Option::filter`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.filter
[`String::replace_range`]: https://doc.rust-lang.org/std/string/struct.String.html#method.replace_range
[`Take::set_limit`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.set_limit
[`hint::unreachable_unchecked`]: https://doc.rust-lang.org/std/hint/fn.unreachable_unchecked.html
[`os::unix::process::parent_id`]: https://doc.rust-lang.org/std/os/unix/process/fn.parent_id.html
[`process::id`]: https://doc.rust-lang.org/std/process/fn.id.html
[`ptr::swap_nonoverlapping`]: https://doc.rust-lang.org/std/ptr/fn.swap_nonoverlapping.html
[`slice::rsplit_mut`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rsplit_mut
[`slice::rsplit`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rsplit
[`slice::swap_with_slice`]: https://doc.rust-lang.org/std/primitive.slice.html#method.swap_with_slice
[`arch::x86_64`]: https://doc.rust-lang.org/std/arch/x86_64/index.html
[`arch::x86`]: https://doc.rust-lang.org/std/arch/x86/index.html
[“The Rustc book”]: https://doc.rust-lang.org/rustc
Version 1.26.2 (2018-06-05)
==========================
Compatibility Notes
-------------------
- [The borrow checker was fixed to avoid unsoundness when using match ergonomics.][51117]
[51117]: https://github.com/rust-lang/rust/issues/51117
Version 1.26.1 (2018-05-29)
==========================
Tools
-----
- [RLS now works on Windows.][50646]
- [Rustfmt stopped badly formatting text in some cases.][rustfmt/2695]
Compatibility Notes
--------
- [`fn main() -> impl Trait` no longer works for non-Termination
trait.][50656]
This reverts an accidental stabilization.
- [`NaN > NaN` no longer returns true in const-fn contexts.][50812]
- [Prohibit using turbofish for `impl Trait` in method arguments.][50950]
[50646]: https://github.com/rust-lang/rust/issues/50646
[50656]: https://github.com/rust-lang/rust/pull/50656
[50812]: https://github.com/rust-lang/rust/pull/50812
[50950]: https://github.com/rust-lang/rust/issues/50950
[rustfmt/2695]: https://github.com/rust-lang-nursery/rustfmt/issues/2695
Version 1.26.0 (2018-05-10)
==========================
Language
--------
- [Closures now implement `Copy` and/or `Clone` if all captured variables
implement either or both traits.][49299]
- [The inclusive range syntax e.g. `for x in 0..=10` is now stable.][47813]
- [The `'_` lifetime is now stable. The underscore lifetime can be used anywhere a
lifetime can be elided.][49458]
- [`impl Trait` is now stable allowing you to have abstract types in returns
or in function parameters.][49255] E.g. `fn foo() -> impl Iterator` or
`fn open(path: impl AsRef)`.
- [Pattern matching will now automatically apply dereferences.][49394]
- [128-bit integers in the form of `u128` and `i128` are now stable.][49101]
- [`main` can now return `Result<(), E: Debug>`][49162] in addition to `()`.
- [A lot of operations are now available in a const context.][46882] E.g. You
can now index into constant arrays, reference and dereference into constants,
and use tuple struct constructors.
- [Fixed entry slice patterns are now stable.][48516] E.g.
```rust
let points = [1, 2, 3, 4];
match points {
[1, 2, 3, 4] => println!("All points were sequential."),
_ => println!("Not all points were sequential."),
}
```
Compiler
--------
- [LLD is now used as the default linker for `wasm32-unknown-unknown`.][48125]
- [Fixed exponential projection complexity on nested types.][48296]
This can provide up to a ~12% reduction in compile times for certain crates.
- [Added the `--remap-path-prefix` option to rustc.][48359] Allowing you
to remap path prefixes outputted by the compiler.
- [Added `powerpc-unknown-netbsd` target.][48281]
Libraries
---------
- [Implemented `From for usize` & `From<{u8, i16}> for isize`.][49305]
- [Added hexadecimal formatting for integers with fmt::Debug][48978]
e.g. `assert!(format!("{:02x?}", b"Foo\0") == "[46, 6f, 6f, 00]")`
- [Implemented `Default, Hash` for `cmp::Reverse`.][48628]
- [Optimized `str::repeat` being 8x faster in large cases.][48657]
- [`ascii::escape_default` is now available in libcore.][48735]
- [Trailing commas are now supported in std and core macros.][48056]
- [Implemented `Copy, Clone` for `cmp::Reverse`][47379]
- [Implemented `Clone` for `char::{ToLowercase, ToUppercase}`.][48629]
Stabilized APIs
---------------
- [`*const T::add`]
- [`*const T::copy_to_nonoverlapping`]
- [`*const T::copy_to`]
- [`*const T::read_unaligned`]
- [`*const T::read_volatile`]
- [`*const T::read`]
- [`*const T::sub`]
- [`*const T::wrapping_add`]
- [`*const T::wrapping_sub`]
- [`*mut T::add`]
- [`*mut T::copy_to_nonoverlapping`]
- [`*mut T::copy_to`]
- [`*mut T::read_unaligned`]
- [`*mut T::read_volatile`]
- [`*mut T::read`]
- [`*mut T::replace`]
- [`*mut T::sub`]
- [`*mut T::swap`]
- [`*mut T::wrapping_add`]
- [`*mut T::wrapping_sub`]
- [`*mut T::write_bytes`]
- [`*mut T::write_unaligned`]
- [`*mut T::write_volatile`]
- [`*mut T::write`]
- [`Box::leak`]
- [`FromUtf8Error::as_bytes`]
- [`LocalKey::try_with`]
- [`Option::cloned`]
- [`btree_map::Entry::and_modify`]
- [`fs::read_to_string`]
- [`fs::read`]
- [`fs::write`]
- [`hash_map::Entry::and_modify`]
- [`iter::FusedIterator`]
- [`ops::RangeInclusive`]
- [`ops::RangeToInclusive`]
- [`process::id`]
- [`slice::rotate_left`]
- [`slice::rotate_right`]
- [`String::retain`]
Cargo
-----
- [Cargo will now output path to custom commands when `-v` is
passed with `--list`][cargo/5041]
- [The Cargo binary version is now the same as the Rust version][cargo/5083]
Misc
----
- [The second edition of "The Rust Programming Language" book is now recommended
over the first.][48404]
Compatibility Notes
-------------------
- [aliasing a `Fn` trait as `dyn` no longer works.][48481] E.g. the following
syntax is now invalid.
```
use std::ops::Fn as dyn;
fn g(_: Box) {}
```
- [The result of dereferences are no longer promoted to `'static`.][47408]
e.g.
```rust
fn main() {
const PAIR: &(i32, i32) = &(0, 1);
let _reversed_pair: &'static _ = &(PAIR.1, PAIR.0); // Doesn't work
}
```
- [Deprecate `AsciiExt` trait in favor of inherent methods.][49109]
- [`".e0"` will now no longer parse as `0.0` and will instead cause
an error.][48235]
- [Removed hoedown from rustdoc.][48274]
- [Bounds on higher-kinded lifetimes a hard error.][48326]
[46882]: https://github.com/rust-lang/rust/pull/46882
[47379]: https://github.com/rust-lang/rust/pull/47379
[47408]: https://github.com/rust-lang/rust/pull/47408
[47813]: https://github.com/rust-lang/rust/pull/47813
[48056]: https://github.com/rust-lang/rust/pull/48056
[48125]: https://github.com/rust-lang/rust/pull/48125
[48235]: https://github.com/rust-lang/rust/pull/48235
[48274]: https://github.com/rust-lang/rust/pull/48274
[48281]: https://github.com/rust-lang/rust/pull/48281
[48296]: https://github.com/rust-lang/rust/pull/48296
[48326]: https://github.com/rust-lang/rust/pull/48326
[48359]: https://github.com/rust-lang/rust/pull/48359
[48404]: https://github.com/rust-lang/rust/pull/48404
[48481]: https://github.com/rust-lang/rust/pull/48481
[48516]: https://github.com/rust-lang/rust/pull/48516
[48628]: https://github.com/rust-lang/rust/pull/48628
[48629]: https://github.com/rust-lang/rust/pull/48629
[48657]: https://github.com/rust-lang/rust/pull/48657
[48735]: https://github.com/rust-lang/rust/pull/48735
[48978]: https://github.com/rust-lang/rust/pull/48978
[49101]: https://github.com/rust-lang/rust/pull/49101
[49109]: https://github.com/rust-lang/rust/pull/49109
[49162]: https://github.com/rust-lang/rust/pull/49162
[49255]: https://github.com/rust-lang/rust/pull/49255
[49299]: https://github.com/rust-lang/rust/pull/49299
[49305]: https://github.com/rust-lang/rust/pull/49305
[49394]: https://github.com/rust-lang/rust/pull/49394
[49458]: https://github.com/rust-lang/rust/pull/49458
[`*const T::add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add
[`*const T::copy_to_nonoverlapping`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to_nonoverlapping
[`*const T::copy_to`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to
[`*const T::read_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_unaligned
[`*const T::read_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_volatile
[`*const T::read`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read
[`*const T::sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.sub
[`*const T::wrapping_add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_add
[`*const T::wrapping_sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_sub
[`*mut T::add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add-1
[`*mut T::copy_to_nonoverlapping`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to_nonoverlapping-1
[`*mut T::copy_to`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.copy_to-1
[`*mut T::read_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_unaligned-1
[`*mut T::read_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read_volatile-1
[`*mut T::read`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.read-1
[`*mut T::replace`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.replace
[`*mut T::sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.sub-1
[`*mut T::swap`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.swap
[`*mut T::wrapping_add`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_add-1
[`*mut T::wrapping_sub`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_sub-1
[`*mut T::write_bytes`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_bytes
[`*mut T::write_unaligned`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_unaligned
[`*mut T::write_volatile`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write_volatile
[`*mut T::write`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.write
[`Box::leak`]: https://doc.rust-lang.org/std/boxed/struct.Box.html#method.leak
[`FromUtf8Error::as_bytes`]: https://doc.rust-lang.org/std/string/struct.FromUtf8Error.html#method.as_bytes
[`LocalKey::try_with`]: https://doc.rust-lang.org/std/thread/struct.LocalKey.html#method.try_with
[`Option::cloned`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.cloned
[`btree_map::Entry::and_modify`]: https://doc.rust-lang.org/std/collections/btree_map/enum.Entry.html#method.and_modify
[`fs::read_to_string`]: https://doc.rust-lang.org/std/fs/fn.read_to_string.html
[`fs::read`]: https://doc.rust-lang.org/std/fs/fn.read.html
[`fs::write`]: https://doc.rust-lang.org/std/fs/fn.write.html
[`hash_map::Entry::and_modify`]: https://doc.rust-lang.org/std/collections/hash_map/enum.Entry.html#method.and_modify
[`iter::FusedIterator`]: https://doc.rust-lang.org/std/iter/trait.FusedIterator.html
[`ops::RangeInclusive`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html
[`ops::RangeToInclusive`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html
[`process::id`]: https://doc.rust-lang.org/std/process/fn.id.html
[`slice::rotate_left`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate_left
[`slice::rotate_right`]: https://doc.rust-lang.org/std/primitive.slice.html#method.rotate_right
[`String::retain`]: https://doc.rust-lang.org/std/string/struct.String.html#method.retain
[cargo/5041]: https://github.com/rust-lang/cargo/pull/5041
[cargo/5083]: https://github.com/rust-lang/cargo/pull/5083
Version 1.25.0 (2018-03-29)
==========================
Language
--------
- [The `#[repr(align(x))]` attribute is now stable.][47006] [RFC 1358]
- [You can now use nested groups of imports.][47948]
e.g. `use std::{fs::File, io::Read, path::{Path, PathBuf}};`
- [You can now have `|` at the start of a match arm.][47947] e.g.
```rust
enum Foo { A, B, C }
fn main() {
let x = Foo::A;
match x {
| Foo::A
| Foo::B => println!("AB"),
| Foo::C => println!("C"),
}
}
```
Compiler
--------
- [Upgraded to LLVM 6.][47828]
- [Added `-C lto=val` option.][47521]
- [Added `i586-unknown-linux-musl` target][47282]
Libraries
---------
- [Impl Send for `process::Command` on Unix.][47760]
- [Impl PartialEq and Eq for `ParseCharError`.][47790]
- [`UnsafeCell::into_inner` is now safe.][47204]
- [Implement libstd for CloudABI.][47268]
- [`Float::{from_bits, to_bits}` is now available in libcore.][46931]
- [Implement `AsRef` for Component][46985]
- [Implemented `Write` for `Cursor<&mut Vec>`][46830]
- [Moved `Duration` to libcore.][46666]
Stabilized APIs
---------------
- [`Location::column`]
- [`ptr::NonNull`]
The following functions can now be used in a constant expression.
eg. `static MINUTE: Duration = Duration::from_secs(60);`
- [`Duration::new`][47300]
- [`Duration::from_secs`][47300]
- [`Duration::from_millis`][47300]
Cargo
-----
- [`cargo new` no longer removes `rust` or `rs` prefixes/suffixes.][cargo/5013]
- [`cargo new` now defaults to creating a binary crate, instead of a
library crate.][cargo/5029]
Misc
----
- [Rust by example is now shipped with new releases][46196]
Compatibility Notes
-------------------
- [Deprecated `net::lookup_host`.][47510]
- [`rustdoc` has switched to pulldown as the default markdown renderer.][47398]
- The borrow checker was sometimes incorrectly permitting overlapping borrows
around indexing operations (see [#47349][47349]). This has been fixed (which also
enabled some correct code that used to cause errors (e.g. [#33903][33903] and [#46095][46095]).
- [Removed deprecated unstable attribute `#[simd]`.][47251]
[33903]: https://github.com/rust-lang/rust/pull/33903
[47947]: https://github.com/rust-lang/rust/pull/47947
[47948]: https://github.com/rust-lang/rust/pull/47948
[47760]: https://github.com/rust-lang/rust/pull/47760
[47790]: https://github.com/rust-lang/rust/pull/47790
[47828]: https://github.com/rust-lang/rust/pull/47828
[47398]: https://github.com/rust-lang/rust/pull/47398
[47510]: https://github.com/rust-lang/rust/pull/47510
[47521]: https://github.com/rust-lang/rust/pull/47521
[47204]: https://github.com/rust-lang/rust/pull/47204
[47251]: https://github.com/rust-lang/rust/pull/47251
[47268]: https://github.com/rust-lang/rust/pull/47268
[47282]: https://github.com/rust-lang/rust/pull/47282
[47300]: https://github.com/rust-lang/rust/pull/47300
[47349]: https://github.com/rust-lang/rust/pull/47349
[46931]: https://github.com/rust-lang/rust/pull/46931
[46985]: https://github.com/rust-lang/rust/pull/46985
[47006]: https://github.com/rust-lang/rust/pull/47006
[46830]: https://github.com/rust-lang/rust/pull/46830
[46095]: https://github.com/rust-lang/rust/pull/46095
[46666]: https://github.com/rust-lang/rust/pull/46666
[46196]: https://github.com/rust-lang/rust/pull/46196
[cargo/5013]: https://github.com/rust-lang/cargo/pull/5013
[cargo/5029]: https://github.com/rust-lang/cargo/pull/5029
[RFC 1358]: https://github.com/rust-lang/rfcs/pull/1358
[`Location::column`]: https://doc.rust-lang.org/std/panic/struct.Location.html#method.column
[`ptr::NonNull`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html
Version 1.24.1 (2018-03-01)
==========================
- [Do not abort when unwinding through FFI][48251]
- [Emit UTF-16 files for linker arguments on Windows][48318]
- [Make the error index generator work again][48308]
- [Cargo will warn on Windows 7 if an update is needed][cargo/5069].
[48251]: https://github.com/rust-lang/rust/issues/48251
[48308]: https://github.com/rust-lang/rust/issues/48308
[48318]: https://github.com/rust-lang/rust/issues/48318
[cargo/5069]: https://github.com/rust-lang/cargo/pull/5069
Version 1.24.0 (2018-02-15)
==========================
Language
--------
- [External `sysv64` ffi is now available.][46528]
eg. `extern "sysv64" fn foo () {}`
Compiler
--------
- [rustc now uses 16 codegen units by default for release builds.][46910]
For the fastest builds, utilize `codegen-units=1`.
- [Added `armv4t-unknown-linux-gnueabi` target.][47018]
- [Add `aarch64-unknown-openbsd` support][46760]
Libraries
---------
- [`str::find::` now uses memchr.][46735] This should lead to a 10x
improvement in performance in the majority of cases.
- [`OsStr`'s `Debug` implementation is now lossless and consistent
with Windows.][46798]
- [`time::{SystemTime, Instant}` now implement `Hash`.][46828]
- [impl `From` for `AtomicBool`][46293]
- [impl `From<{CString, &CStr}>` for `{Arc, Rc}`][45990]
- [impl `From<{OsString, &OsStr}>` for `{Arc, Rc}`][45990]
- [impl `From<{PathBuf, &Path}>` for `{Arc, Rc}`][45990]
- [float::from_bits now just uses transmute.][46012] This provides
some optimisations from LLVM.
- [Copied `AsciiExt` methods onto `char`][46077]
- [Remove `T: Sized` requirement on `ptr::is_null()`][46094]
- [impl `From` for `{TryRecvError, RecvTimeoutError}`][45506]
- [Optimised `f32::{min, max}` to generate more efficient x86 assembly][47080]
- [`[u8]::contains` now uses memchr which provides a 3x speed improvement][46713]
Stabilized APIs
---------------
- [`RefCell::replace`]
- [`RefCell::swap`]
- [`atomic::spin_loop_hint`]
The following functions can now be used in a constant expression.
eg. `let buffer: [u8; size_of::()];`, `static COUNTER: AtomicUsize = AtomicUsize::new(1);`
- [`AtomicBool::new`][46287]
- [`AtomicUsize::new`][46287]
- [`AtomicIsize::new`][46287]
- [`AtomicPtr::new`][46287]
- [`Cell::new`][46287]
- [`{integer}::min_value`][46287]
- [`{integer}::max_value`][46287]
- [`mem::size_of`][46287]
- [`mem::align_of`][46287]
- [`ptr::null`][46287]
- [`ptr::null_mut`][46287]
- [`RefCell::new`][46287]
- [`UnsafeCell::new`][46287]
Cargo
-----
- [Added a `workspace.default-members` config that
overrides implied `--all` in virtual workspaces.][cargo/4743]
- [Enable incremental by default on development builds.][cargo/4817] Also added
configuration keys to `Cargo.toml` and `.cargo/config` to disable on a
per-project or global basis respectively.
Misc
----
Compatibility Notes
-------------------
- [Floating point types `Debug` impl now always prints a decimal point.][46831]
- [`Ipv6Addr` now rejects superfluous `::`'s in IPv6 addresses][46671] This is
in accordance with IETF RFC 4291 §2.2.
- [Unwinding will no longer go past FFI boundaries, and will instead abort.][46833]
- [`Formatter::flags` method is now deprecated.][46284] The `sign_plus`,
`sign_minus`, `alternate`, and `sign_aware_zero_pad` should be used instead.
- [Leading zeros in tuple struct members is now an error][47084]
- [`column!()` macro is one-based instead of zero-based][46977]
- [`fmt::Arguments` can no longer be shared across threads][45198]
- [Access to `#[repr(packed)]` struct fields is now unsafe][44884]
- [Cargo sets a different working directory for the compiler][cargo/4788]
[44884]: https://github.com/rust-lang/rust/pull/44884
[45198]: https://github.com/rust-lang/rust/pull/45198
[45506]: https://github.com/rust-lang/rust/pull/45506
[45990]: https://github.com/rust-lang/rust/pull/45990
[46012]: https://github.com/rust-lang/rust/pull/46012
[46077]: https://github.com/rust-lang/rust/pull/46077
[46094]: https://github.com/rust-lang/rust/pull/46094
[46284]: https://github.com/rust-lang/rust/pull/46284
[46287]: https://github.com/rust-lang/rust/pull/46287
[46293]: https://github.com/rust-lang/rust/pull/46293
[46528]: https://github.com/rust-lang/rust/pull/46528
[46671]: https://github.com/rust-lang/rust/pull/46671
[46713]: https://github.com/rust-lang/rust/pull/46713
[46735]: https://github.com/rust-lang/rust/pull/46735
[46760]: https://github.com/rust-lang/rust/pull/46760
[46798]: https://github.com/rust-lang/rust/pull/46798
[46828]: https://github.com/rust-lang/rust/pull/46828
[46831]: https://github.com/rust-lang/rust/pull/46831
[46833]: https://github.com/rust-lang/rust/pull/46833
[46910]: https://github.com/rust-lang/rust/pull/46910
[46977]: https://github.com/rust-lang/rust/pull/46977
[47018]: https://github.com/rust-lang/rust/pull/47018
[47080]: https://github.com/rust-lang/rust/pull/47080
[47084]: https://github.com/rust-lang/rust/pull/47084
[cargo/4743]: https://github.com/rust-lang/cargo/pull/4743
[cargo/4788]: https://github.com/rust-lang/cargo/pull/4788
[cargo/4817]: https://github.com/rust-lang/cargo/pull/4817
[`RefCell::replace`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.replace
[`RefCell::swap`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.swap
[`atomic::spin_loop_hint`]: https://doc.rust-lang.org/std/sync/atomic/fn.spin_loop_hint.html
Version 1.23.0 (2018-01-04)
==========================
Language
--------
- [Arbitrary `auto` traits are now permitted in trait objects.][45772]
- [rustc now uses subtyping on the left hand side of binary operations.][45435]
Which should fix some confusing errors in some operations.
Compiler
--------
- [Enabled `TrapUnreachable` in LLVM which should mitigate the impact of
undefined behavior.][45920]
- [rustc now suggests renaming import if names clash.][45660]
- [Display errors/warnings correctly when there are zero-width or
wide characters.][45711]
- [rustc now avoids unnecessary copies of arguments that are
simple bindings][45380] This should improve memory usage on average by 5-10%.
- [Updated musl used to build musl rustc to 1.1.17][45393]
Libraries
---------
- [Allow a trailing comma in `assert_eq/ne` macro][45887]
- [Implement Hash for raw pointers to unsized types][45483]
- [impl `From<*mut T>` for `AtomicPtr`][45610]
- [impl `From` for `AtomicUsize/AtomicIsize`.][45610]
- [Removed the `T: Sync` requirement for `RwLock: Send`][45267]
- [Removed `T: Sized` requirement for `{<*const T>, <*mut T>}::as_ref`
and `<*mut T>::as_mut`][44932]
- [Optimized `Thread::{park, unpark}` implementation][45524]
- [Improved `SliceExt::binary_search` performance.][45333]
- [impl `FromIterator<()>` for `()`][45379]
- [Copied `AsciiExt` trait methods to primitive types.][44042] Use of `AsciiExt`
is now deprecated.
Stabilized APIs
---------------
Cargo
-----
- [Cargo now supports uninstallation of multiple packages][cargo/4561]
eg. `cargo uninstall foo bar` uninstalls `foo` and `bar`.
- [Added unit test checking to `cargo check`][cargo/4592]
- [Cargo now lets you install a specific version
using `cargo install --version`][cargo/4637]
Misc
----
- [Releases now ship with the Cargo book documentation.][45692]
- [rustdoc now prints rendering warnings on every run.][45324]
Compatibility Notes
-------------------
- [Changes have been made to type equality to make it more correct,
in rare cases this could break some code.][45853] [Tracking issue for
further information][45852]
- [`char::escape_debug` now uses Unicode 10 over 9.][45571]
- [Upgraded Android SDK to 27, and NDK to r15c.][45580] This drops support for
Android 9, the minimum supported version is Android 14.
- [Bumped the minimum LLVM to 3.9][45326]
[44042]: https://github.com/rust-lang/rust/pull/44042
[44932]: https://github.com/rust-lang/rust/pull/44932
[45267]: https://github.com/rust-lang/rust/pull/45267
[45324]: https://github.com/rust-lang/rust/pull/45324
[45326]: https://github.com/rust-lang/rust/pull/45326
[45333]: https://github.com/rust-lang/rust/pull/45333
[45379]: https://github.com/rust-lang/rust/pull/45379
[45380]: https://github.com/rust-lang/rust/pull/45380
[45393]: https://github.com/rust-lang/rust/pull/45393
[45435]: https://github.com/rust-lang/rust/pull/45435
[45483]: https://github.com/rust-lang/rust/pull/45483
[45524]: https://github.com/rust-lang/rust/pull/45524
[45571]: https://github.com/rust-lang/rust/pull/45571
[45580]: https://github.com/rust-lang/rust/pull/45580
[45610]: https://github.com/rust-lang/rust/pull/45610
[45660]: https://github.com/rust-lang/rust/pull/45660
[45692]: https://github.com/rust-lang/rust/pull/45692
[45711]: https://github.com/rust-lang/rust/pull/45711
[45772]: https://github.com/rust-lang/rust/pull/45772
[45852]: https://github.com/rust-lang/rust/issues/45852
[45853]: https://github.com/rust-lang/rust/pull/45853
[45887]: https://github.com/rust-lang/rust/pull/45887
[45920]: https://github.com/rust-lang/rust/pull/45920
[cargo/4561]: https://github.com/rust-lang/cargo/pull/4561
[cargo/4592]: https://github.com/rust-lang/cargo/pull/4592
[cargo/4637]: https://github.com/rust-lang/cargo/pull/4637
Version 1.22.1 (2017-11-22)
==========================
- [Update Cargo to fix an issue with macOS 10.13 "High Sierra"][46183]
[46183]: https://github.com/rust-lang/rust/pull/46183
Version 1.22.0 (2017-11-22)
==========================
Language
--------
- [`non_snake_case` lint now allows extern no-mangle functions][44966]
- [Now accepts underscores in unicode escapes][43716]
- [`T op= &T` now works for numeric types.][44287] eg. `let mut x = 2; x += &8;`
- [types that impl `Drop` are now allowed in `const` and `static` types][44456]
Compiler
--------
- [rustc now defaults to having 16 codegen units at debug on supported platforms.][45064]
- [rustc will no longer inline in codegen units when compiling for debug][45075]
This should decrease compile times for debug builds.
- [strict memory alignment now enabled on ARMv6][45094]
- [Remove support for the PNaCl target `le32-unknown-nacl`][45041]
Libraries
---------
- [Allow atomic operations up to 32 bits
on `armv5te_unknown_linux_gnueabi`][44978]
- [`Box` now impls `From>`][44466]
- [`std::mem::Discriminant` is now guaranteed to be `Send + Sync`][45095]
- [`fs::copy` now returns the length of the main stream on NTFS.][44895]
- [Properly detect overflow in `Instant += Duration`.][44220]
- [impl `Hasher` for `{&mut Hasher, Box}`][44015]
- [impl `fmt::Debug` for `SplitWhitespace`.][44303]
- [`Option` now impls `Try`][42526] This allows for using `?` with `Option` types.
Stabilized APIs
---------------
Cargo
-----
- [Cargo will now build multi file examples in subdirectories of the `examples`
folder that have a `main.rs` file.][cargo/4496]
- [Changed `[root]` to `[package]` in `Cargo.lock`][cargo/4571] Packages with
the old format will continue to work and can be updated with `cargo update`.
- [Now supports vendoring git repositories][cargo/3992]
Misc
----
- [`libbacktrace` is now available on Apple platforms.][44251]
- [Stabilised the `compile_fail` attribute for code fences in doc-comments.][43949]
This now lets you specify that a given code example will fail to compile.
Compatibility Notes
-------------------
- [The minimum Android version that rustc can build for has been bumped
to `4.0` from `2.3`][45656]
- [Allowing `T op= &T` for numeric types has broken some type
inference cases][45480]
[42526]: https://github.com/rust-lang/rust/pull/42526
[43716]: https://github.com/rust-lang/rust/pull/43716
[43949]: https://github.com/rust-lang/rust/pull/43949
[44015]: https://github.com/rust-lang/rust/pull/44015
[44220]: https://github.com/rust-lang/rust/pull/44220
[44251]: https://github.com/rust-lang/rust/pull/44251
[44287]: https://github.com/rust-lang/rust/pull/44287
[44303]: https://github.com/rust-lang/rust/pull/44303
[44456]: https://github.com/rust-lang/rust/pull/44456
[44466]: https://github.com/rust-lang/rust/pull/44466
[44895]: https://github.com/rust-lang/rust/pull/44895
[44966]: https://github.com/rust-lang/rust/pull/44966
[44978]: https://github.com/rust-lang/rust/pull/44978
[45041]: https://github.com/rust-lang/rust/pull/45041
[45064]: https://github.com/rust-lang/rust/pull/45064
[45075]: https://github.com/rust-lang/rust/pull/45075
[45094]: https://github.com/rust-lang/rust/pull/45094
[45095]: https://github.com/rust-lang/rust/pull/45095
[45480]: https://github.com/rust-lang/rust/issues/45480
[45656]: https://github.com/rust-lang/rust/pull/45656
[cargo/3992]: https://github.com/rust-lang/cargo/pull/3992
[cargo/4496]: https://github.com/rust-lang/cargo/pull/4496
[cargo/4571]: https://github.com/rust-lang/cargo/pull/4571
Version 1.21.0 (2017-10-12)
==========================
Language
--------
- [You can now use static references for literals.][43838]
Example:
```rust
fn main() {
let x: &'static u32 = &0;
}
```
- [Relaxed path syntax. Optional `::` before `<` is now allowed in all contexts.][43540]
Example:
```rust
my_macro!(Vec::new); // Always worked
my_macro!(Vec::::new); // Now works
```
Compiler
--------
- [Upgraded jemalloc to 4.5.0][43911]
- [Enabled unwinding panics on Redox][43917]
- [Now runs LLVM in parallel during translation phase.][43506]
This should reduce peak memory usage.
Libraries
---------
- [Generate builtin impls for `Clone` for all arrays and tuples that
are `T: Clone`][43690]
- [`Stdin`, `Stdout`, and `Stderr` now implement `AsRawFd`.][43459]
- [`Rc` and `Arc` now implement `From<&[T]> where T: Clone`, `From`,
`From`, `From> where T: ?Sized`, and `From>`.][42565]
Stabilized APIs
---------------
[`std::mem::discriminant`]
Cargo
-----
- [You can now call `cargo install` with multiple package names][cargo/4216]
- [Cargo commands inside a virtual workspace will now implicitly
pass `--all`][cargo/4335]
- [Added a `[patch]` section to `Cargo.toml` to handle
prepublication dependencies][cargo/4123] [RFC 1969]
- [`include` & `exclude` fields in `Cargo.toml` now accept gitignore
like patterns][cargo/4270]
- [Added the `--all-targets` option][cargo/4400]
- [Using required dependencies as a feature is now deprecated and emits
a warning][cargo/4364]
Misc
----
- [Cargo docs are moving][43916]
to [doc.rust-lang.org/cargo](https://doc.rust-lang.org/cargo)
- [The rustdoc book is now available][43863]
at [doc.rust-lang.org/rustdoc](https://doc.rust-lang.org/rustdoc)
- [Added a preview of RLS has been made available through rustup][44204]
Install with `rustup component add rls-preview`
- [`std::os` documentation for Unix, Linux, and Windows now appears on doc.rust-lang.org][43348]
Previously only showed `std::os::unix`.
Compatibility Notes
-------------------
- [Changes in method matching against higher-ranked types][43880] This may cause
breakage in subtyping corner cases. [A more in-depth explanation is available.][info/43880]
- [rustc's JSON error output's byte position start at top of file.][42973]
Was previously relative to the rustc's internal `CodeMap` struct which
required the unstable library `libsyntax` to correctly use.
- [`unused_results` lint no longer ignores booleans][43728]
[42565]: https://github.com/rust-lang/rust/pull/42565
[42973]: https://github.com/rust-lang/rust/pull/42973
[43348]: https://github.com/rust-lang/rust/pull/43348
[43459]: https://github.com/rust-lang/rust/pull/43459
[43506]: https://github.com/rust-lang/rust/pull/43506
[43540]: https://github.com/rust-lang/rust/pull/43540
[43690]: https://github.com/rust-lang/rust/pull/43690
[43728]: https://github.com/rust-lang/rust/pull/43728
[43838]: https://github.com/rust-lang/rust/pull/43838
[43863]: https://github.com/rust-lang/rust/pull/43863
[43880]: https://github.com/rust-lang/rust/pull/43880
[43911]: https://github.com/rust-lang/rust/pull/43911
[43916]: https://github.com/rust-lang/rust/pull/43916
[43917]: https://github.com/rust-lang/rust/pull/43917
[44204]: https://github.com/rust-lang/rust/pull/44204
[cargo/4123]: https://github.com/rust-lang/cargo/pull/4123
[cargo/4216]: https://github.com/rust-lang/cargo/pull/4216
[cargo/4270]: https://github.com/rust-lang/cargo/pull/4270
[cargo/4335]: https://github.com/rust-lang/cargo/pull/4335
[cargo/4364]: https://github.com/rust-lang/cargo/pull/4364
[cargo/4400]: https://github.com/rust-lang/cargo/pull/4400
[RFC 1969]: https://github.com/rust-lang/rfcs/pull/1969
[info/43880]: https://github.com/rust-lang/rust/issues/44224#issuecomment-330058902
[`std::mem::discriminant`]: https://doc.rust-lang.org/std/mem/fn.discriminant.html
Version 1.20.0 (2017-08-31)
===========================
Language
--------
- [Associated constants are now stabilised.][42809]
- [A lot of macro bugs are now fixed.][42913]
Compiler
--------
- [Struct fields are now properly coerced to the expected field type.][42807]
- [Enabled wasm LLVM backend][42571] WASM can now be built with the
`wasm32-experimental-emscripten` target.
- [Changed some of the error messages to be more helpful.][42033]
- [Add support for RELRO(RELocation Read-Only) for platforms that support
it.][43170]
- [rustc now reports the total number of errors on compilation failure][43015]
previously this was only the number of errors in the pass that failed.
- [Expansion in rustc has been sped up 29x.][42533]
- [added `msp430-none-elf` target.][43099]
- [rustc will now suggest one-argument enum variant to fix type mismatch when
applicable][43178]
- [Fixes backtraces on Redox][43228]
- [rustc now identifies different versions of same crate when absolute paths of
different types match in an error message.][42826]
Libraries
---------
- [Relaxed Debug constraints on `{HashMap,BTreeMap}::{Keys,Values}`.][42854]
- [Impl `PartialEq`, `Eq`, `PartialOrd`, `Ord`, `Debug`, `Hash` for unsized
tuples.][43011]
- [Impl `fmt::{Display, Debug}` for `Ref`, `RefMut`, `MutexGuard`,
`RwLockReadGuard`, `RwLockWriteGuard`][42822]
- [Impl `Clone` for `DefaultHasher`.][42799]
- [Impl `Sync` for `SyncSender`.][42397]
- [Impl `FromStr` for `char`][42271]
- [Fixed how `{f32, f64}::{is_sign_negative, is_sign_positive}` handles
NaN.][42431]
- [allow messages in the `unimplemented!()` macro.][42155]
ie. `unimplemented!("Waiting for 1.21 to be stable")`
- [`pub(restricted)` is now supported in the `thread_local!` macro.][43185]
- [Upgrade to Unicode 10.0.0][42999]
- [Reimplemented `{f32, f64}::{min, max}` in Rust instead of using CMath.][42430]
- [Skip the main thread's manual stack guard on Linux][43072]
- [Iterator::nth for `ops::{Range, RangeFrom}` is now done in *O*(1) time][43077]
- [`#[repr(align(N))]` attribute max number is now 2^31 - 1.][43097] This was
previously 2^15.
- [`{OsStr, Path}::Display` now avoids allocations where possible][42613]
Stabilized APIs
---------------
- [`CStr::into_c_string`]
- [`CString::as_c_str`]
- [`CString::into_boxed_c_str`]
- [`Chain::get_mut`]
- [`Chain::get_ref`]
- [`Chain::into_inner`]
- [`Option::get_or_insert_with`]
- [`Option::get_or_insert`]
- [`OsStr::into_os_string`]
- [`OsString::into_boxed_os_str`]
- [`Take::get_mut`]
- [`Take::get_ref`]
- [`Utf8Error::error_len`]
- [`char::EscapeDebug`]
- [`char::escape_debug`]
- [`compile_error!`]
- [`f32::from_bits`]
- [`f32::to_bits`]
- [`f64::from_bits`]
- [`f64::to_bits`]
- [`mem::ManuallyDrop`]
- [`slice::sort_unstable_by_key`]
- [`slice::sort_unstable_by`]
- [`slice::sort_unstable`]
- [`str::from_boxed_utf8_unchecked`]
- [`str::as_bytes_mut`]
- [`str::as_bytes_mut`]
- [`str::from_utf8_mut`]
- [`str::from_utf8_unchecked_mut`]
- [`str::get_mut`]
- [`str::get_unchecked_mut`]
- [`str::get_unchecked`]
- [`str::get`]
- [`str::into_boxed_bytes`]
Cargo
-----
- [Cargo API token location moved from `~/.cargo/config` to
`~/.cargo/credentials`.][cargo/3978]
- [Cargo will now build `main.rs` binaries that are in sub-directories of
`src/bin`.][cargo/4214] ie. Having `src/bin/server/main.rs` and
`src/bin/client/main.rs` generates `target/debug/server` and `target/debug/client`
- [You can now specify version of a binary when installed through
`cargo install` using `--vers`.][cargo/4229]
- [Added `--no-fail-fast` flag to cargo to run all benchmarks regardless of
failure.][cargo/4248]
- [Changed the convention around which file is the crate root.][cargo/4259]
Compatibility Notes
-------------------
- [Functions with `'static` in their return types will now not be as usable as
if they were using lifetime parameters instead.][42417]
- [The reimplementation of `{f32, f64}::is_sign_{negative, positive}` now
takes the sign of NaN into account where previously didn't.][42430]
[42033]: https://github.com/rust-lang/rust/pull/42033
[42155]: https://github.com/rust-lang/rust/pull/42155
[42271]: https://github.com/rust-lang/rust/pull/42271
[42397]: https://github.com/rust-lang/rust/pull/42397
[42417]: https://github.com/rust-lang/rust/pull/42417
[42430]: https://github.com/rust-lang/rust/pull/42430
[42431]: https://github.com/rust-lang/rust/pull/42431
[42533]: https://github.com/rust-lang/rust/pull/42533
[42571]: https://github.com/rust-lang/rust/pull/42571
[42613]: https://github.com/rust-lang/rust/pull/42613
[42799]: https://github.com/rust-lang/rust/pull/42799
[42807]: https://github.com/rust-lang/rust/pull/42807
[42809]: https://github.com/rust-lang/rust/pull/42809
[42822]: https://github.com/rust-lang/rust/pull/42822
[42826]: https://github.com/rust-lang/rust/pull/42826
[42854]: https://github.com/rust-lang/rust/pull/42854
[42913]: https://github.com/rust-lang/rust/pull/42913
[42999]: https://github.com/rust-lang/rust/pull/42999
[43011]: https://github.com/rust-lang/rust/pull/43011
[43015]: https://github.com/rust-lang/rust/pull/43015
[43072]: https://github.com/rust-lang/rust/pull/43072
[43077]: https://github.com/rust-lang/rust/pull/43077
[43097]: https://github.com/rust-lang/rust/pull/43097
[43099]: https://github.com/rust-lang/rust/pull/43099
[43170]: https://github.com/rust-lang/rust/pull/43170
[43178]: https://github.com/rust-lang/rust/pull/43178
[43185]: https://github.com/rust-lang/rust/pull/43185
[43228]: https://github.com/rust-lang/rust/pull/43228
[cargo/3978]: https://github.com/rust-lang/cargo/pull/3978
[cargo/4214]: https://github.com/rust-lang/cargo/pull/4214
[cargo/4229]: https://github.com/rust-lang/cargo/pull/4229
[cargo/4248]: https://github.com/rust-lang/cargo/pull/4248
[cargo/4259]: https://github.com/rust-lang/cargo/pull/4259
[`CStr::into_c_string`]: https://doc.rust-lang.org/std/ffi/struct.CStr.html#method.into_c_string
[`CString::as_c_str`]: https://doc.rust-lang.org/std/ffi/struct.CString.html#method.as_c_str
[`CString::into_boxed_c_str`]: https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str
[`Chain::get_mut`]: https://doc.rust-lang.org/std/io/struct.Chain.html#method.get_mut
[`Chain::get_ref`]: https://doc.rust-lang.org/std/io/struct.Chain.html#method.get_ref
[`Chain::into_inner`]: https://doc.rust-lang.org/std/io/struct.Chain.html#method.into_inner
[`Option::get_or_insert_with`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.get_or_insert_with
[`Option::get_or_insert`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.get_or_insert
[`OsStr::into_os_string`]: https://doc.rust-lang.org/std/ffi/struct.OsStr.html#method.into_os_string
[`OsString::into_boxed_os_str`]: https://doc.rust-lang.org/std/ffi/struct.OsString.html#method.into_boxed_os_str
[`Take::get_mut`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.get_mut
[`Take::get_ref`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.get_ref
[`Utf8Error::error_len`]: https://doc.rust-lang.org/std/str/struct.Utf8Error.html#method.error_len
[`char::EscapeDebug`]: https://doc.rust-lang.org/std/char/struct.EscapeDebug.html
[`char::escape_debug`]: https://doc.rust-lang.org/std/primitive.char.html#method.escape_debug
[`compile_error!`]: https://doc.rust-lang.org/std/macro.compile_error.html
[`f32::from_bits`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_bits
[`f32::to_bits`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_bits
[`f64::from_bits`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_bits
[`f64::to_bits`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_bits
[`mem::ManuallyDrop`]: https://doc.rust-lang.org/std/mem/union.ManuallyDrop.html
[`slice::sort_unstable_by_key`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_unstable_by_key
[`slice::sort_unstable_by`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_unstable_by
[`slice::sort_unstable`]: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_unstable
[`str::from_boxed_utf8_unchecked`]: https://doc.rust-lang.org/std/str/fn.from_boxed_utf8_unchecked.html
[`str::as_bytes_mut`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_bytes_mut
[`str::from_utf8_mut`]: https://doc.rust-lang.org/std/str/fn.from_utf8_mut.html
[`str::from_utf8_unchecked_mut`]: https://doc.rust-lang.org/std/str/fn.from_utf8_unchecked_mut.html
[`str::get_mut`]: https://doc.rust-lang.org/std/primitive.str.html#method.get_mut
[`str::get_unchecked_mut`]: https://doc.rust-lang.org/std/primitive.str.html#method.get_unchecked_mut
[`str::get_unchecked`]: https://doc.rust-lang.org/std/primitive.str.html#method.get_unchecked
[`str::get`]: https://doc.rust-lang.org/std/primitive.str.html#method.get
[`str::into_boxed_bytes`]: https://doc.rust-lang.org/std/primitive.str.html#method.into_boxed_bytes
Version 1.19.0 (2017-07-20)
===========================
Language
--------
- [Numeric fields can now be used for creating tuple structs.][41145] [RFC 1506]
For example `struct Point(u32, u32); let x = Point { 0: 7, 1: 0 };`.
- [Macro recursion limit increased to 1024 from 64.][41676]
- [Added lint for detecting unused macros.][41907]
- [`loop` can now return a value with `break`.][42016] [RFC 1624]
For example: `let x = loop { break 7; };`
- [C compatible `union`s are now available.][42068] [RFC 1444] They can only
contain `Copy` types and cannot have a `Drop` implementation.
Example: `union Foo { bar: u8, baz: usize }`
- [Non capturing closures can now be coerced into `fn`s,][42162] [RFC 1558]
Example: `let foo: fn(u8) -> u8 = |v: u8| { v };`
Compiler
--------
- [Add support for bootstrapping the Rust compiler toolchain on Android.][41370]
- [Change `arm-linux-androideabi` to correspond to the `armeabi`
official ABI.][41656] If you wish to continue targeting the `armeabi-v7a` ABI
you should use `--target armv7-linux-androideabi`.
- [Fixed ICE when removing a source file between compilation sessions.][41873]
- [Minor optimisation of string operations.][42037]
- [Compiler error message is now `aborting due to previous error(s)` instead of
`aborting due to N previous errors`][42150] This was previously inaccurate and
would only count certain kinds of errors.
- [The compiler now supports Visual Studio 2017][42225]
- [The compiler is now built against LLVM 4.0.1 by default][42948]
- [Added a lot][42264] of [new error codes][42302]
- [Added `target-feature=+crt-static` option][37406] [RFC 1721] Which allows
libraries with C Run-time Libraries(CRT) to be statically linked.
- [Fixed various ARM codegen bugs][42740]
Libraries
---------
- [`String` now implements `FromIterator>` and
`Extend>`][41449]
- [`Vec` now implements `From<&mut [T]>`][41530]
- [`Box<[u8]>` now implements `From>`][41258]
- [`SplitWhitespace` now implements `Clone`][41659]
- [`[u8]::reverse` is now 5x faster and `[u16]::reverse` is now
1.5x faster][41764]
- [`eprint!` and `eprintln!` macros added to prelude.][41192] Same as the `print!`
macros, but for printing to stderr.
Stabilized APIs
---------------
- [`OsString::shrink_to_fit`]
- [`cmp::Reverse`]
- [`Command::envs`]
- [`thread::ThreadId`]
Cargo
-----
- [Build scripts can now add environment variables to the environment
the crate is being compiled in.
Example: `println!("cargo:rustc-env=FOO=bar");`][cargo/3929]
- [Subcommands now replace the current process rather than spawning a new
child process][cargo/3970]
- [Workspace members can now accept glob file patterns][cargo/3979]
- [Added `--all` flag to the `cargo bench` subcommand to run benchmarks of all
the members in a given workspace.][cargo/3988]
- [Updated `libssh2-sys` to 0.2.6][cargo/4008]
- [Target directory path is now in the cargo metadata][cargo/4022]
- [Cargo no longer checks out a local working directory for the
crates.io index][cargo/4026] This should provide smaller file size for the
registry, and improve cloning times, especially on Windows machines.
- [Added an `--exclude` option for excluding certain packages when using the
`--all` option][cargo/4031]
- [Cargo will now automatically retry when receiving a 5xx error
from crates.io][cargo/4032]
- [The `--features` option now accepts multiple comma or space
delimited values.][cargo/4084]
- [Added support for custom target specific runners][cargo/3954]
Misc
----
- [Added `rust-windbg.cmd`][39983] for loading rust `.natvis` files in the
Windows Debugger.
- [Rust will now release XZ compressed packages][rust-installer/57]
- [rustup will now prefer to download rust packages with
XZ compression][rustup/1100] over GZip packages.
- [Added the ability to escape `#` in rust documentation][41785] By adding
additional `#`'s ie. `##` is now `#`
Compatibility Notes
-------------------
- [`MutexGuard` may only be `Sync` if `T` is `Sync`.][41624]
- [`-Z` flags are now no longer allowed to be used on the stable
compiler.][41751] This has been a warning for a year previous to this.
- [As a result of the `-Z` flag change, the `cargo-check` plugin no
longer works][42844]. Users should migrate to the built-in `check`
command, which has been available since 1.16.
- [Ending a float literal with `._` is now a hard error.
Example: `42._` .][41946]
- [Any use of a private `extern crate` outside of its module is now a
hard error.][36886] This was previously a warning.
- [`use ::self::foo;` is now a hard error.][36888] `self` paths are always
relative while the `::` prefix makes a path absolute, but was ignored and the
path was relative regardless.
- [Floating point constants in match patterns is now a hard error][36890]
This was previously a warning.
- [Struct or enum constants that don't derive `PartialEq` & `Eq` used
match patterns is now a hard error][36891] This was previously a warning.
- [Lifetimes named `'_` are no longer allowed.][36892] This was previously
a warning.
- [From the pound escape, lines consisting of multiple `#`s are
now visible][41785]
- [It is an error to re-export private enum variants][42460]. This is
known to break a number of crates that depend on an older version of
mustache.
- [On Windows, if `VCINSTALLDIR` is set incorrectly, `rustc` will try
to use it to find the linker, and the build will fail where it did
not previously][42607]
[36886]: https://github.com/rust-lang/rust/issues/36886
[36888]: https://github.com/rust-lang/rust/issues/36888
[36890]: https://github.com/rust-lang/rust/issues/36890
[36891]: https://github.com/rust-lang/rust/issues/36891
[36892]: https://github.com/rust-lang/rust/issues/36892
[37406]: https://github.com/rust-lang/rust/issues/37406
[39983]: https://github.com/rust-lang/rust/pull/39983
[41145]: https://github.com/rust-lang/rust/pull/41145
[41192]: https://github.com/rust-lang/rust/pull/41192
[41258]: https://github.com/rust-lang/rust/pull/41258
[41370]: https://github.com/rust-lang/rust/pull/41370
[41449]: https://github.com/rust-lang/rust/pull/41449
[41530]: https://github.com/rust-lang/rust/pull/41530
[41624]: https://github.com/rust-lang/rust/pull/41624
[41656]: https://github.com/rust-lang/rust/pull/41656
[41659]: https://github.com/rust-lang/rust/pull/41659
[41676]: https://github.com/rust-lang/rust/pull/41676
[41751]: https://github.com/rust-lang/rust/pull/41751
[41764]: https://github.com/rust-lang/rust/pull/41764
[41785]: https://github.com/rust-lang/rust/pull/41785
[41873]: https://github.com/rust-lang/rust/pull/41873
[41907]: https://github.com/rust-lang/rust/pull/41907
[41946]: https://github.com/rust-lang/rust/pull/41946
[42016]: https://github.com/rust-lang/rust/pull/42016
[42037]: https://github.com/rust-lang/rust/pull/42037
[42068]: https://github.com/rust-lang/rust/pull/42068
[42150]: https://github.com/rust-lang/rust/pull/42150
[42162]: https://github.com/rust-lang/rust/pull/42162
[42225]: https://github.com/rust-lang/rust/pull/42225
[42264]: https://github.com/rust-lang/rust/pull/42264
[42302]: https://github.com/rust-lang/rust/pull/42302
[42460]: https://github.com/rust-lang/rust/issues/42460
[42607]: https://github.com/rust-lang/rust/issues/42607
[42740]: https://github.com/rust-lang/rust/pull/42740
[42844]: https://github.com/rust-lang/rust/issues/42844
[42948]: https://github.com/rust-lang/rust/pull/42948
[RFC 1444]: https://github.com/rust-lang/rfcs/pull/1444
[RFC 1506]: https://github.com/rust-lang/rfcs/pull/1506
[RFC 1558]: https://github.com/rust-lang/rfcs/pull/1558
[RFC 1624]: https://github.com/rust-lang/rfcs/pull/1624
[RFC 1721]: https://github.com/rust-lang/rfcs/pull/1721
[`Command::envs`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.envs
[`OsString::shrink_to_fit`]: https://doc.rust-lang.org/std/ffi/struct.OsString.html#method.shrink_to_fit
[`cmp::Reverse`]: https://doc.rust-lang.org/std/cmp/struct.Reverse.html
[`thread::ThreadId`]: https://doc.rust-lang.org/std/thread/struct.ThreadId.html
[cargo/3929]: https://github.com/rust-lang/cargo/pull/3929
[cargo/3954]: https://github.com/rust-lang/cargo/pull/3954
[cargo/3970]: https://github.com/rust-lang/cargo/pull/3970
[cargo/3979]: https://github.com/rust-lang/cargo/pull/3979
[cargo/3988]: https://github.com/rust-lang/cargo/pull/3988
[cargo/4008]: https://github.com/rust-lang/cargo/pull/4008
[cargo/4022]: https://github.com/rust-lang/cargo/pull/4022
[cargo/4026]: https://github.com/rust-lang/cargo/pull/4026
[cargo/4031]: https://github.com/rust-lang/cargo/pull/4031
[cargo/4032]: https://github.com/rust-lang/cargo/pull/4032
[cargo/4084]: https://github.com/rust-lang/cargo/pull/4084
[rust-installer/57]: https://github.com/rust-lang/rust-installer/pull/57
[rustup/1100]: https://github.com/rust-lang-nursery/rustup.rs/pull/1100
Version 1.18.0 (2017-06-08)
===========================
Language
--------
- [Stabilize pub(restricted)][40556] `pub` can now accept a module path to
make the item visible to just that module tree. Also accepts the keyword
`crate` to make something public to the whole crate but not users of the
library. Example: `pub(crate) mod utils;`. [RFC 1422].
- [Stabilize `#![windows_subsystem]` attribute][40870] conservative exposure of the
`/SUBSYSTEM` linker flag on Windows platforms. [RFC 1665].
- [Refactor of trait object type parsing][40043] Now `ty` in macros can accept
types like `Write + Send`, trailing `+` are now supported in trait objects,
and better error reporting for trait objects starting with `?Sized`.
- [0e+10 is now a valid floating point literal][40589]
- [Now warns if you bind a lifetime parameter to 'static][40734]
- [Tuples, Enum variant fields, and structs with no `repr` attribute or with
`#[repr(Rust)]` are reordered to minimize padding and produce a smaller
representation in some cases.][40377]
Compiler
--------
- [rustc can now emit mir with `--emit mir`][39891]
- [Improved LLVM IR for trivial functions][40367]
- [Added explanation for E0090(Wrong number of lifetimes are supplied)][40723]
- [rustc compilation is now 15%-20% faster][41469] Thanks to optimisation
opportunities found through profiling
- [Improved backtrace formatting when panicking][38165]
Libraries
---------
- [Specialized `Vec::from_iter` being passed `vec::IntoIter`][40731] if the
iterator hasn't been advanced the original `Vec` is reassembled with no actual
iteration or reallocation.
- [Simplified HashMap Bucket interface][40561] provides performance
improvements for iterating and cloning.
- [Specialize Vec::from_elem to use calloc][40409]
- [Fixed Race condition in fs::create_dir_all][39799]
- [No longer caching stdio on Windows][40516]
- [Optimized insertion sort in slice][40807] insertion sort in some cases
2.50%~ faster and in one case now 12.50% faster.
- [Optimized `AtomicBool::fetch_nand`][41143]
Stabilized APIs
---------------
- [`Child::try_wait`]
- [`HashMap::retain`]
- [`HashSet::retain`]
- [`PeekMut::pop`]
- [`TcpStream::peek`]
- [`UdpSocket::peek`]
- [`UdpSocket::peek_from`]
Cargo
-----
- [Added partial Pijul support][cargo/3842] Pijul is a version control system in Rust.
You can now create new cargo projects with Pijul using `cargo new --vcs pijul`
- [Now always emits build script warnings for crates that fail to build][cargo/3847]
- [Added Android build support][cargo/3885]
- [Added `--bins` and `--tests` flags][cargo/3901] now you can build all programs
of a certain type, for example `cargo build --bins` will build all
binaries.
- [Added support for haiku][cargo/3952]
Misc
----
- [rustdoc can now use pulldown-cmark with the `--enable-commonmark` flag][40338]
- [Rust now uses the official cross compiler for NetBSD][40612]
- [rustdoc now accepts `#` at the start of files][40828]
- [Fixed jemalloc support for musl][41168]
Compatibility Notes
-------------------
- [Changes to how the `0` flag works in format!][40241] Padding zeroes are now
always placed after the sign if it exists and before the digits. With the `#`
flag the zeroes are placed after the prefix and before the digits.
- [Due to the struct field optimisation][40377], using `transmute` on structs
that have no `repr` attribute or `#[repr(Rust)]` will no longer work. This has
always been undefined behavior, but is now more likely to break in practice.
- [The refactor of trait object type parsing][40043] fixed a bug where `+` was
receiving the wrong priority parsing things like `&for<'a> Tr<'a> + Send` as
`&(for<'a> Tr<'a> + Send)` instead of `(&for<'a> Tr<'a>) + Send`
- [Overlapping inherent `impl`s are now a hard error][40728]
- [`PartialOrd` and `Ord` must agree on the ordering.][41270]
- [`rustc main.rs -o out --emit=asm,llvm-ir`][41085] Now will output
`out.asm` and `out.ll` instead of only one of the filetypes.
- [ calling a function that returns `Self` will no longer work][41805] when
the size of `Self` cannot be statically determined.
- [rustc now builds with a "pthreads" flavour of MinGW for Windows GNU][40805]
this has caused a few regressions namely:
- Changed the link order of local static/dynamic libraries (respecting the
order on given rather than having the compiler reorder).
- Changed how MinGW is linked, native code linked to dynamic libraries
may require manually linking to the gcc support library (for the native
code itself)
[38165]: https://github.com/rust-lang/rust/pull/38165
[39799]: https://github.com/rust-lang/rust/pull/39799
[39891]: https://github.com/rust-lang/rust/pull/39891
[40043]: https://github.com/rust-lang/rust/pull/40043
[40241]: https://github.com/rust-lang/rust/pull/40241
[40338]: https://github.com/rust-lang/rust/pull/40338
[40367]: https://github.com/rust-lang/rust/pull/40367
[40377]: https://github.com/rust-lang/rust/pull/40377
[40409]: https://github.com/rust-lang/rust/pull/40409
[40516]: https://github.com/rust-lang/rust/pull/40516
[40556]: https://github.com/rust-lang/rust/pull/40556
[40561]: https://github.com/rust-lang/rust/pull/40561
[40589]: https://github.com/rust-lang/rust/pull/40589
[40612]: https://github.com/rust-lang/rust/pull/40612
[40723]: https://github.com/rust-lang/rust/pull/40723
[40728]: https://github.com/rust-lang/rust/pull/40728
[40731]: https://github.com/rust-lang/rust/pull/40731
[40734]: https://github.com/rust-lang/rust/pull/40734
[40805]: https://github.com/rust-lang/rust/pull/40805
[40807]: https://github.com/rust-lang/rust/pull/40807
[40828]: https://github.com/rust-lang/rust/pull/40828
[40870]: https://github.com/rust-lang/rust/pull/40870
[41085]: https://github.com/rust-lang/rust/pull/41085
[41143]: https://github.com/rust-lang/rust/pull/41143
[41168]: https://github.com/rust-lang/rust/pull/41168
[41270]: https://github.com/rust-lang/rust/issues/41270
[41469]: https://github.com/rust-lang/rust/pull/41469
[41805]: https://github.com/rust-lang/rust/issues/41805
[RFC 1422]: https://github.com/rust-lang/rfcs/blob/master/text/1422-pub-restricted.md
[RFC 1665]: https://github.com/rust-lang/rfcs/blob/master/text/1665-windows-subsystem.md
[`Child::try_wait`]: https://doc.rust-lang.org/std/process/struct.Child.html#method.try_wait
[`HashMap::retain`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.retain
[`HashSet::retain`]: https://doc.rust-lang.org/std/collections/struct.HashSet.html#method.retain
[`PeekMut::pop`]: https://doc.rust-lang.org/std/collections/binary_heap/struct.PeekMut.html#method.pop
[`TcpStream::peek`]: https://doc.rust-lang.org/std/net/struct.TcpStream.html#method.peek
[`UdpSocket::peek_from`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peek_from
[`UdpSocket::peek`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peek
[cargo/3842]: https://github.com/rust-lang/cargo/pull/3842
[cargo/3847]: https://github.com/rust-lang/cargo/pull/3847
[cargo/3885]: https://github.com/rust-lang/cargo/pull/3885
[cargo/3901]: https://github.com/rust-lang/cargo/pull/3901
[cargo/3952]: https://github.com/rust-lang/cargo/pull/3952
Version 1.17.0 (2017-04-27)
===========================
Language
--------
* [The lifetime of statics and consts defaults to `'static`][39265]. [RFC 1623]
* [Fields of structs may be initialized without duplicating the field/variable
names][39761]. [RFC 1682]
* [`Self` may be included in the `where` clause of `impls`][38864]. [RFC 1647]
* [When coercing to an unsized type lifetimes must be equal][40319]. That is,
there is no subtyping between `T` and `U` when `T: Unsize`. For example,
coercing `&mut [&'a X; N]` to `&mut [&'b X]` requires `'a` be equal to
`'b`. Soundness fix.
* [Values passed to the indexing operator, `[]`, automatically coerce][40166]
* [Static variables may contain references to other statics][40027]
Compiler
--------
* [Exit quickly on only `--emit dep-info`][40336]
* [Make `-C relocation-model` more correctly determine whether the linker
creates a position-independent executable][40245]
* [Add `-C overflow-checks` to directly control whether integer overflow
panics][40037]
* [The rustc type checker now checks items on demand instead of in a single
in-order pass][40008]. This is mostly an internal refactoring in support of
future work, including incremental type checking, but also resolves [RFC
1647], allowing `Self` to appear in `impl` `where` clauses.
* [Optimize vtable loads][39995]
* [Turn off vectorization for Emscripten targets][39990]
* [Provide suggestions for unknown macros imported with `use`][39953]
* [Fix ICEs in path resolution][39939]
* [Strip exception handling code on Emscripten when `panic=abort`][39193]
* [Add clearer error message using `&str + &str`][39116]
Stabilized APIs
---------------
* [`Arc::into_raw`]
* [`Arc::from_raw`]
* [`Arc::ptr_eq`]
* [`Rc::into_raw`]
* [`Rc::from_raw`]
* [`Rc::ptr_eq`]
* [`Ordering::then`]
* [`Ordering::then_with`]
* [`BTreeMap::range`]
* [`BTreeMap::range_mut`]
* [`collections::Bound`]
* [`process::abort`]
* [`ptr::read_unaligned`]
* [`ptr::write_unaligned`]
* [`Result::expect_err`]
* [`Cell::swap`]
* [`Cell::replace`]
* [`Cell::into_inner`]
* [`Cell::take`]
Libraries
---------
* [`BTreeMap` and `BTreeSet` can iterate over ranges][27787]
* [`Cell` can store non-`Copy` types][39793]. [RFC 1651]
* [`String` implements `FromIterator<&char>`][40028]
* `Box` [implements][40009] a number of new conversions:
`From> for String`,
`From> for Vec`,
`From> for CString`,
`From> for OsString`,
`From> for PathBuf`,
`Into> for String`,
`Into> for Vec`,
`Into> for CString`,
`Into> for OsString`,
`Into> for PathBuf`,
`Default for Box`,
`Default for Box`,
`Default for Box`,
`From<&CStr> for Box`,
`From<&OsStr> for Box`,
`From<&Path> for Box`
* [`ffi::FromBytesWithNulError` implements `Error` and `Display`][39960]
* [Specialize `PartialOrd for [A] where A: Ord`][39642]
* [Slightly optimize `slice::sort`][39538]
* [Add `ToString` trait specialization for `Cow<'a, str>` and `String`][39440]
* [`Box<[T]>` implements `From<&[T]> where T: Copy`,
`Box` implements `From<&str>`][39438]
* [`IpAddr` implements `From` for various arrays. `SocketAddr` implements
`From<(I, u16)> where I: Into`][39372]
* [`format!` estimates the needed capacity before writing a string][39356]
* [Support unprivileged symlink creation in Windows][38921]
* [`PathBuf` implements `Default`][38764]
* [Implement `PartialEq<[A]>` for `VecDeque`][38661]
* [`HashMap` resizes adaptively][38368] to guard against DOS attacks
and poor hash functions.
Cargo
-----
* [Add `cargo check --all`][cargo/3731]
* [Add an option to ignore SSL revocation checking][cargo/3699]
* [Add `cargo run --package`][cargo/3691]
* [Add `required_features`][cargo/3667]
* [Assume `build.rs` is a build script][cargo/3664]
* [Find workspace via `workspace_root` link in containing member][cargo/3562]
Misc
----
* [Documentation is rendered with mdbook instead of the obsolete, in-tree
`rustbook`][39633]
* [The "Unstable Book" documents nightly-only features][ubook]
* [Improve the style of the sidebar in rustdoc output][40265]
* [Configure build correctly on 64-bit CPU's with the armhf ABI][40261]
* [Fix MSP430 breakage due to `i128`][40257]
* [Preliminary Solaris/SPARCv9 support][39903]
* [`rustc` is linked statically on Windows MSVC targets][39837], allowing it to
run without installing the MSVC runtime.
* [`rustdoc --test` includes file names in test names][39788]
* This release includes builds of `std` for `sparc64-unknown-linux-gnu`,
`aarch64-unknown-linux-fuchsia`, and `x86_64-unknown-linux-fuchsia`.
* [Initial support for `aarch64-unknown-freebsd`][39491]
* [Initial support for `i686-unknown-netbsd`][39426]
* [This release no longer includes the old makefile build system][39431]. Rust
is built with a custom build system, written in Rust, and with Cargo.
* [Add Debug implementations for libcollection structs][39002]
* [`TypeId` implements `PartialOrd` and `Ord`][38981]
* [`--test-threads=0` produces an error][38945]
* [`rustup` installs documentation by default][40526]
* [The Rust source includes NatVis visualizations][39843]. These can be used by
WinDbg and Visual Studio to improve the debugging experience.
Compatibility Notes
-------------------
* [Rust 1.17 does not correctly detect the MSVC 2017 linker][38584]. As a
workaround, either use MSVC 2015 or run vcvars.bat.
* [When coercing to an unsized type lifetimes must be equal][40319]. That is,
disallow subtyping between `T` and `U` when `T: Unsize`, e.g. coercing
`&mut [&'a X; N]` to `&mut [&'b X]` requires `'a` be equal to `'b`. Soundness
fix.
* [`format!` and `Display::to_string` panic if an underlying formatting
implementation returns an error][40117]. Previously the error was silently
ignored. It is incorrect for `write_fmt` to return an error when writing
to a string.
* [In-tree crates are verified to be unstable][39851]. Previously, some minor
crates were marked stable and could be accessed from the stable toolchain.
* [Rust git source no longer includes vendored crates][39728]. Those that need
to build with vendored crates should build from release tarballs.
* [Fix inert attributes from `proc_macro_derives`][39572]
* [During crate resolution, rustc prefers a crate in the sysroot if two crates
are otherwise identical][39518]. Unlikely to be encountered outside the Rust
build system.
* [Fixed bugs around how type inference interacts with dead-code][39485]. The
existing code generally ignores the type of dead-code unless a type-hint is
provided; this can cause surprising inference interactions particularly around
defaulting. The new code uniformly ignores the result type of dead-code.
* [Tuple-struct constructors with private fields are no longer visible][38932]
* [Lifetime parameters that do not appear in the arguments are now considered
early-bound][38897], resolving a soundness bug (#[32330]). The
`hr_lifetime_in_assoc_type` future-compatibility lint has been in effect since
April of 2016.
* [rustdoc: fix doctests with non-feature crate attributes][38161]
* [Make transmuting from fn item types to pointer-sized types a hard
error][34198]
[27787]: https://github.com/rust-lang/rust/issues/27787
[32330]: https://github.com/rust-lang/rust/issues/32330
[34198]: https://github.com/rust-lang/rust/pull/34198
[38161]: https://github.com/rust-lang/rust/pull/38161
[38368]: https://github.com/rust-lang/rust/pull/38368
[38584]: https://github.com/rust-lang/rust/issues/38584
[38661]: https://github.com/rust-lang/rust/pull/38661
[38764]: https://github.com/rust-lang/rust/pull/38764
[38864]: https://github.com/rust-lang/rust/issues/38864
[38897]: https://github.com/rust-lang/rust/pull/38897
[38921]: https://github.com/rust-lang/rust/pull/38921
[38932]: https://github.com/rust-lang/rust/pull/38932
[38945]: https://github.com/rust-lang/rust/pull/38945
[38981]: https://github.com/rust-lang/rust/pull/38981
[39002]: https://github.com/rust-lang/rust/pull/39002
[39116]: https://github.com/rust-lang/rust/pull/39116
[39193]: https://github.com/rust-lang/rust/pull/39193
[39265]: https://github.com/rust-lang/rust/pull/39265
[39356]: https://github.com/rust-lang/rust/pull/39356
[39372]: https://github.com/rust-lang/rust/pull/39372
[39426]: https://github.com/rust-lang/rust/pull/39426
[39431]: https://github.com/rust-lang/rust/pull/39431
[39438]: https://github.com/rust-lang/rust/pull/39438
[39440]: https://github.com/rust-lang/rust/pull/39440
[39485]: https://github.com/rust-lang/rust/pull/39485
[39491]: https://github.com/rust-lang/rust/pull/39491
[39518]: https://github.com/rust-lang/rust/pull/39518
[39538]: https://github.com/rust-lang/rust/pull/39538
[39572]: https://github.com/rust-lang/rust/pull/39572
[39633]: https://github.com/rust-lang/rust/pull/39633
[39642]: https://github.com/rust-lang/rust/pull/39642
[39728]: https://github.com/rust-lang/rust/pull/39728
[39761]: https://github.com/rust-lang/rust/pull/39761
[39788]: https://github.com/rust-lang/rust/pull/39788
[39793]: https://github.com/rust-lang/rust/pull/39793
[39837]: https://github.com/rust-lang/rust/pull/39837
[39843]: https://github.com/rust-lang/rust/pull/39843
[39851]: https://github.com/rust-lang/rust/pull/39851
[39903]: https://github.com/rust-lang/rust/pull/39903
[39939]: https://github.com/rust-lang/rust/pull/39939
[39953]: https://github.com/rust-lang/rust/pull/39953
[39960]: https://github.com/rust-lang/rust/pull/39960
[39990]: https://github.com/rust-lang/rust/pull/39990
[39995]: https://github.com/rust-lang/rust/pull/39995
[40008]: https://github.com/rust-lang/rust/pull/40008
[40009]: https://github.com/rust-lang/rust/pull/40009
[40027]: https://github.com/rust-lang/rust/pull/40027
[40028]: https://github.com/rust-lang/rust/pull/40028
[40037]: https://github.com/rust-lang/rust/pull/40037
[40117]: https://github.com/rust-lang/rust/pull/40117
[40166]: https://github.com/rust-lang/rust/pull/40166
[40245]: https://github.com/rust-lang/rust/pull/40245
[40257]: https://github.com/rust-lang/rust/pull/40257
[40261]: https://github.com/rust-lang/rust/pull/40261
[40265]: https://github.com/rust-lang/rust/pull/40265
[40319]: https://github.com/rust-lang/rust/pull/40319
[40336]: https://github.com/rust-lang/rust/pull/40336
[40526]: https://github.com/rust-lang/rust/pull/40526
[RFC 1623]: https://github.com/rust-lang/rfcs/blob/master/text/1623-static.md
[RFC 1647]: https://github.com/rust-lang/rfcs/blob/master/text/1647-allow-self-in-where-clauses.md
[RFC 1651]: https://github.com/rust-lang/rfcs/blob/master/text/1651-movecell.md
[RFC 1682]: https://github.com/rust-lang/rfcs/blob/master/text/1682-field-init-shorthand.md
[`Arc::from_raw`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.from_raw
[`Arc::into_raw`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.into_raw
[`Arc::ptr_eq`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.ptr_eq
[`BTreeMap::range_mut`]: https://doc.rust-lang.org/std/collections/btree_map/struct.BTreeMap.html#method.range_mut
[`BTreeMap::range`]: https://doc.rust-lang.org/std/collections/btree_map/struct.BTreeMap.html#method.range
[`Cell::into_inner`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.into_inner
[`Cell::replace`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.replace
[`Cell::swap`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.swap
[`Cell::take`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.take
[`Ordering::then_with`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then_with
[`Ordering::then`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then
[`Rc::from_raw`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.from_raw
[`Rc::into_raw`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.into_raw
[`Rc::ptr_eq`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.ptr_eq
[`Result::expect_err`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.expect_err
[`collections::Bound`]: https://doc.rust-lang.org/std/collections/enum.Bound.html
[`process::abort`]: https://doc.rust-lang.org/std/process/fn.abort.html
[`ptr::read_unaligned`]: https://doc.rust-lang.org/std/ptr/fn.read_unaligned.html
[`ptr::write_unaligned`]: https://doc.rust-lang.org/std/ptr/fn.write_unaligned.html
[cargo/3562]: https://github.com/rust-lang/cargo/pull/3562
[cargo/3664]: https://github.com/rust-lang/cargo/pull/3664
[cargo/3667]: https://github.com/rust-lang/cargo/pull/3667
[cargo/3691]: https://github.com/rust-lang/cargo/pull/3691
[cargo/3699]: https://github.com/rust-lang/cargo/pull/3699
[cargo/3731]: https://github.com/rust-lang/cargo/pull/3731
[ubook]: https://doc.rust-lang.org/unstable-book/
Version 1.16.0 (2017-03-16)
===========================
Language
--------
* [The compiler's `dead_code` lint now accounts for type aliases][38051].
* [Uninhabitable enums (those without any variants) no longer permit wildcard
match patterns][38069]
* [Clean up semantics of `self` in an import list][38313]
* [`Self` may appear in `impl` headers][38920]
* [`Self` may appear in struct expressions][39282]
Compiler
--------
* [`rustc` now supports `--emit=metadata`, which causes rustc to emit
a `.rmeta` file containing only crate metadata][38571]. This can be
used by tools like the Rust Language Service to perform
metadata-only builds.
* [Levenshtein based typo suggestions now work in most places, while
previously they worked only for fields and sometimes for local
variables][38927]. Together with the overhaul of "no
resolution"/"unexpected resolution" errors (#[38154]) they result in
large and systematic improvement in resolution diagnostics.
* [Fix `transmute::` where `T` requires a bigger alignment than
`U`][38670]
* [rustc: use -Xlinker when specifying an rpath with ',' in it][38798]
* [`rustc` no longer attempts to provide "consider using an explicit
lifetime" suggestions][37057]. They were inaccurate.
Stabilized APIs
---------------
* [`VecDeque::truncate`]
* [`VecDeque::resize`]
* [`String::insert_str`]
* [`Duration::checked_add`]
* [`Duration::checked_sub`]
* [`Duration::checked_div`]
* [`Duration::checked_mul`]
* [`str::replacen`]
* [`str::repeat`]
* [`SocketAddr::is_ipv4`]
* [`SocketAddr::is_ipv6`]
* [`IpAddr::is_ipv4`]
* [`IpAddr::is_ipv6`]
* [`Vec::dedup_by`]
* [`Vec::dedup_by_key`]
* [`Result::unwrap_or_default`]
* [`<*const T>::wrapping_offset`]
* [`<*mut T>::wrapping_offset`]
* `CommandExt::creation_flags`
* [`File::set_permissions`]
* [`String::split_off`]
Libraries
---------
* [`[T]::binary_search` and `[T]::binary_search_by_key` now take
their argument by `Borrow` parameter][37761]
* [All public types in std implement `Debug`][38006]
* [`IpAddr` implements `From` and `From`][38327]
* [`Ipv6Addr` implements `From<[u16; 8]>`][38131]
* [Ctrl-Z returns from `Stdin.read()` when reading from the console on
Windows][38274]
* [std: Fix partial writes in `LineWriter`][38062]
* [std: Clamp max read/write sizes on Unix][38622]
* [Use more specific panic message for `&str` slicing errors][38066]
* [`TcpListener::set_only_v6` is deprecated][38304]. This
functionality cannot be achieved in std currently.
* [`writeln!`, like `println!`, now accepts a form with no string
or formatting arguments, to just print a newline][38469]
* [Implement `iter::Sum` and `iter::Product` for `Result`][38580]
* [Reduce the size of static data in `std_unicode::tables`][38781]
* [`char::EscapeDebug`, `EscapeDefault`, `EscapeUnicode`,
`CaseMappingIter`, `ToLowercase`, `ToUppercase`, implement
`Display`][38909]
* [`Duration` implements `Sum`][38712]
* [`String` implements `ToSocketAddrs`][39048]
Cargo
-----
* [The `cargo check` command does a type check of a project without
building it][cargo/3296]
* [crates.io will display CI badges from Travis and AppVeyor, if
specified in Cargo.toml][cargo/3546]
* [crates.io will display categories listed in Cargo.toml][cargo/3301]
* [Compilation profiles accept integer values for `debug`, in addition
to `true` and `false`. These are passed to `rustc` as the value to
`-C debuginfo`][cargo/3534]
* [Implement `cargo --version --verbose`][cargo/3604]
* [All builds now output 'dep-info' build dependencies compatible with
make and ninja][cargo/3557]
* [Build all workspace members with `build --all`][cargo/3511]
* [Document all workspace members with `doc --all`][cargo/3515]
* [Path deps outside workspace are not members][cargo/3443]
Misc
----
* [`rustdoc` has a `--sysroot` argument that, like `rustc`, specifies
the path to the Rust implementation][38589]
* [The `armv7-linux-androideabi` target no longer enables NEON
extensions, per Google's ABI guide][38413]
* [The stock standard library can be compiled for Redox OS][38401]
* [Rust has initial SPARC support][38726]. Tier 3. No builds
available.
* [Rust has experimental support for Nvidia PTX][38559]. Tier 3. No
builds available.
* [Fix backtraces on i686-pc-windows-gnu by disabling FPO][39379]
Compatibility Notes
-------------------
* [Uninhabitable enums (those without any variants) no longer permit wildcard
match patterns][38069]
* In this release, references to uninhabited types can not be
pattern-matched. This was accidentally allowed in 1.15.
* [The compiler's `dead_code` lint now accounts for type aliases][38051].
* [Ctrl-Z returns from `Stdin.read()` when reading from the console on
Windows][38274]
* [Clean up semantics of `self` in an import list][38313]
* Reimplemented lifetime elision. This change was almost entirely compatible
with existing code, but it did close a number of small bugs and loopholes,
as well as being more accepting in some other [cases][41105].
[37057]: https://github.com/rust-lang/rust/pull/37057
[37761]: https://github.com/rust-lang/rust/pull/37761
[38006]: https://github.com/rust-lang/rust/pull/38006
[38051]: https://github.com/rust-lang/rust/pull/38051
[38062]: https://github.com/rust-lang/rust/pull/38062
[38622]: https://github.com/rust-lang/rust/pull/38622
[38066]: https://github.com/rust-lang/rust/pull/38066
[38069]: https://github.com/rust-lang/rust/pull/38069
[38131]: https://github.com/rust-lang/rust/pull/38131
[38154]: https://github.com/rust-lang/rust/pull/38154
[38274]: https://github.com/rust-lang/rust/pull/38274
[38304]: https://github.com/rust-lang/rust/pull/38304
[38313]: https://github.com/rust-lang/rust/pull/38313
[38327]: https://github.com/rust-lang/rust/pull/38327
[38401]: https://github.com/rust-lang/rust/pull/38401
[38413]: https://github.com/rust-lang/rust/pull/38413
[38469]: https://github.com/rust-lang/rust/pull/38469
[38559]: https://github.com/rust-lang/rust/pull/38559
[38571]: https://github.com/rust-lang/rust/pull/38571
[38580]: https://github.com/rust-lang/rust/pull/38580
[38589]: https://github.com/rust-lang/rust/pull/38589
[38670]: https://github.com/rust-lang/rust/pull/38670
[38712]: https://github.com/rust-lang/rust/pull/38712
[38726]: https://github.com/rust-lang/rust/pull/38726
[38781]: https://github.com/rust-lang/rust/pull/38781
[38798]: https://github.com/rust-lang/rust/pull/38798
[38909]: https://github.com/rust-lang/rust/pull/38909
[38920]: https://github.com/rust-lang/rust/pull/38920
[38927]: https://github.com/rust-lang/rust/pull/38927
[39048]: https://github.com/rust-lang/rust/pull/39048
[39282]: https://github.com/rust-lang/rust/pull/39282
[39379]: https://github.com/rust-lang/rust/pull/39379
[41105]: https://github.com/rust-lang/rust/issues/41105
[`<*const T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset
[`<*mut T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset-1
[`Duration::checked_add`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_add
[`Duration::checked_div`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_div
[`Duration::checked_mul`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_mul
[`Duration::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_sub
[`File::set_permissions`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.set_permissions
[`IpAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv4
[`IpAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv6
[`Result::unwrap_or_default`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_or_default
[`SocketAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv4
[`SocketAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv6
[`String::insert_str`]: https://doc.rust-lang.org/std/string/struct.String.html#method.insert_str
[`String::split_off`]: https://doc.rust-lang.org/std/string/struct.String.html#method.split_off
[`Vec::dedup_by_key`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by_key
[`Vec::dedup_by`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by
[`VecDeque::resize`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.resize
[`VecDeque::truncate`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.truncate
[`str::repeat`]: https://doc.rust-lang.org/std/primitive.str.html#method.repeat
[`str::replacen`]: https://doc.rust-lang.org/std/primitive.str.html#method.replacen
[cargo/3296]: https://github.com/rust-lang/cargo/pull/3296
[cargo/3301]: https://github.com/rust-lang/cargo/pull/3301
[cargo/3443]: https://github.com/rust-lang/cargo/pull/3443
[cargo/3511]: https://github.com/rust-lang/cargo/pull/3511
[cargo/3515]: https://github.com/rust-lang/cargo/pull/3515
[cargo/3534]: https://github.com/rust-lang/cargo/pull/3534
[cargo/3546]: https://github.com/rust-lang/cargo/pull/3546
[cargo/3557]: https://github.com/rust-lang/cargo/pull/3557
[cargo/3604]: https://github.com/rust-lang/cargo/pull/3604
Version 1.15.1 (2017-02-09)
===========================
* [Fix IntoIter::as_mut_slice's signature][39466]
* [Compile compiler builtins with `-fPIC` on 32-bit platforms][39523]
[39466]: https://github.com/rust-lang/rust/pull/39466
[39523]: https://github.com/rust-lang/rust/pull/39523
Version 1.15.0 (2017-02-02)
===========================
Language
--------
* Basic procedural macros allowing custom `#[derive]`, aka "macros 1.1", are
stable. This allows popular code-generating crates like Serde and Diesel to
work ergonomically. [RFC 1681].
* [Tuple structs may be empty. Unary and empty tuple structs may be instantiated
with curly braces][36868]. Part of [RFC 1506].
* [A number of minor changes to name resolution have been activated][37127].
They add up to more consistent semantics, allowing for future evolution of
Rust macros. Specified in [RFC 1560], see its section on ["changes"] for
details of what is different. The breaking changes here have been transitioned
through the [`legacy_imports`] lint since 1.14, with no known regressions.
* [In `macro_rules`, `path` fragments can now be parsed as type parameter
bounds][38279]
* [`?Sized` can be used in `where` clauses][37791]
* [There is now a limit on the size of monomorphized types and it can be
modified with the `#![type_size_limit]` crate attribute, similarly to
the `#![recursion_limit]` attribute][37789]
Compiler
--------
* [On Windows, the compiler will apply dllimport attributes when linking to
extern functions][37973]. Additional attributes and flags can control which
library kind is linked and its name. [RFC 1717].
* [Rust-ABI symbols are no longer exported from cdylibs][38117]
* [The `--test` flag works with procedural macro crates][38107]
* [Fix `extern "aapcs" fn` ABI][37814]
* [The `-C no-stack-check` flag is deprecated][37636]. It does nothing.
* [The `format!` expander recognizes incorrect `printf` and shell-style
formatting directives and suggests the correct format][37613].
* [Only report one error for all unused imports in an import list][37456]
Compiler Performance
--------------------
* [Avoid unnecessary `mk_ty` calls in `Ty::super_fold_with`][37705]
* [Avoid more unnecessary `mk_ty` calls in `Ty::super_fold_with`][37979]
* [Don't clone in `UnificationTable::probe`][37848]
* [Remove `scope_auxiliary` to cut RSS by 10%][37764]
* [Use small vectors in type walker][37760]
* [Macro expansion performance was improved][37701]
* [Change `HirVec>` to `HirVec` in `hir::Expr`][37642]
* [Replace FNV with a faster hash function][37229]
Stabilized APIs
---------------
* [`std::iter::Iterator::min_by`]
* [`std::iter::Iterator::max_by`]
* [`std::os::*::fs::FileExt`]
* [`std::sync::atomic::Atomic*::get_mut`]
* [`std::sync::atomic::Atomic*::into_inner`]
* [`std::vec::IntoIter::as_slice`]
* [`std::vec::IntoIter::as_mut_slice`]
* [`std::sync::mpsc::Receiver::try_iter`]
* [`std::os::unix::process::CommandExt::before_exec`]
* [`std::rc::Rc::strong_count`]
* [`std::rc::Rc::weak_count`]
* [`std::sync::Arc::strong_count`]
* [`std::sync::Arc::weak_count`]
* [`std::char::encode_utf8`]
* [`std::char::encode_utf16`]
* [`std::cell::Ref::clone`]
* [`std::io::Take::into_inner`]
Libraries
---------
* [The standard sorting algorithm has been rewritten for dramatic performance
improvements][38192]. It is a hybrid merge sort, drawing influences from
Timsort. Previously it was a naive merge sort.
* [`Iterator::nth` no longer has a `Sized` bound][38134]
* [`Extend<&T>` is specialized for `Vec` where `T: Copy`][38182] to improve
performance.
* [`chars().count()` is much faster][37888] and so are [`chars().last()`
and `char_indices().last()`][37882]
* [Fix ARM Objective-C ABI in `std::env::args`][38146]
* [Chinese characters display correctly in `fmt::Debug`][37855]
* [Derive `Default` for `Duration`][37699]
* [Support creation of anonymous pipes on WinXP/2k][37677]
* [`mpsc::RecvTimeoutError` implements `Error`][37527]
* [Don't pass overlapped handles to processes][38835]
Cargo
-----
* [In this release, Cargo build scripts no longer have access to the `OUT_DIR`
environment variable at build time via `env!("OUT_DIR")`][cargo/3368]. They
should instead check the variable at runtime with `std::env`. That the value
was set at build time was a bug, and incorrect when cross-compiling. This
change is known to cause breakage.
* [Add `--all` flag to `cargo test`][cargo/3221]
* [Compile statically against the MSVC CRT][cargo/3363]
* [Mix feature flags into fingerprint/metadata shorthash][cargo/3102]
* [Link OpenSSL statically on OSX][cargo/3311]
* [Apply new fingerprinting to build dir outputs][cargo/3310]
* [Test for bad path overrides with summaries][cargo/3336]
* [Require `cargo install --vers` to take a semver version][cargo/3338]
* [Fix retrying crate downloads for network errors][cargo/3348]
* [Implement string lookup for `build.rustflags` config key][cargo/3356]
* [Emit more info on --message-format=json][cargo/3319]
* [Assume `build.rs` in the same directory as `Cargo.toml` is a build script][cargo/3361]
* [Don't ignore errors in workspace manifest][cargo/3409]
* [Fix `--message-format JSON` when rustc emits non-JSON warnings][cargo/3410]
Tooling
-------
* [Test runners (binaries built with `--test`) now support a `--list` argument
that lists the tests it contains][38185]
* [Test runners now support a `--exact` argument that makes the test filter
match exactly, instead of matching only a substring of the test name][38181]
* [rustdoc supports a `--playground-url` flag][37763]
* [rustdoc provides more details about `#[should_panic]` errors][37749]
Misc
----
* [The Rust build system is now written in Rust][37817]. The Makefiles may
continue to be used in this release by passing `--disable-rustbuild` to the
configure script, but they will be deleted soon. Note that the new build
system uses a different on-disk layout that will likely affect any scripts
building Rust.
* [Rust supports i686-unknown-openbsd][38086]. Tier 3 support. No testing or
releases.
* [Rust supports the MSP430][37627]. Tier 3 support. No testing or releases.
* [Rust supports the ARMv5TE architecture][37615]. Tier 3 support. No testing or
releases.
Compatibility Notes
-------------------
* [A number of minor changes to name resolution have been activated][37127].
They add up to more consistent semantics, allowing for future evolution of
Rust macros. Specified in [RFC 1560], see its section on ["changes"] for
details of what is different. The breaking changes here have been transitioned
through the [`legacy_imports`] lint since 1.14, with no known regressions.
* [In this release, Cargo build scripts no longer have access to the `OUT_DIR`
environment variable at build time via `env!("OUT_DIR")`][cargo/3368]. They
should instead check the variable at runtime with `std::env`. That the value
was set at build time was a bug, and incorrect when cross-compiling. This
change is known to cause breakage.
* [Higher-ranked lifetimes are no longer allowed to appear _only_ in associated
types][33685]. The [`hr_lifetime_in_assoc_type` lint] has been a warning since
1.10 and is now an error by default. It will become a hard error in the near
future.
* [The semantics relating modules to file system directories are changing in
minor ways][37602]. This is captured in the new `legacy_directory_ownership`
lint, which is a warning in this release, and will become a hard error in the
future.
* [Rust-ABI symbols are no longer exported from cdylibs][38117]
* [Once `Peekable` peeks a `None` it will return that `None` without re-querying
the underlying iterator][37834]
["changes"]: https://github.com/rust-lang/rfcs/blob/master/text/1560-name-resolution.md#changes-to-name-resolution-rules
[33685]: https://github.com/rust-lang/rust/issues/33685
[36868]: https://github.com/rust-lang/rust/pull/36868
[37127]: https://github.com/rust-lang/rust/pull/37127
[37229]: https://github.com/rust-lang/rust/pull/37229
[37456]: https://github.com/rust-lang/rust/pull/37456
[37527]: https://github.com/rust-lang/rust/pull/37527
[37602]: https://github.com/rust-lang/rust/pull/37602
[37613]: https://github.com/rust-lang/rust/pull/37613
[37615]: https://github.com/rust-lang/rust/pull/37615
[37636]: https://github.com/rust-lang/rust/pull/37636
[37627]: https://github.com/rust-lang/rust/pull/37627
[37642]: https://github.com/rust-lang/rust/pull/37642
[37677]: https://github.com/rust-lang/rust/pull/37677
[37699]: https://github.com/rust-lang/rust/pull/37699
[37701]: https://github.com/rust-lang/rust/pull/37701
[37705]: https://github.com/rust-lang/rust/pull/37705
[37749]: https://github.com/rust-lang/rust/pull/37749
[37760]: https://github.com/rust-lang/rust/pull/37760
[37763]: https://github.com/rust-lang/rust/pull/37763
[37764]: https://github.com/rust-lang/rust/pull/37764
[37789]: https://github.com/rust-lang/rust/pull/37789
[37791]: https://github.com/rust-lang/rust/pull/37791
[37814]: https://github.com/rust-lang/rust/pull/37814
[37817]: https://github.com/rust-lang/rust/pull/37817
[37834]: https://github.com/rust-lang/rust/pull/37834
[37848]: https://github.com/rust-lang/rust/pull/37848
[37855]: https://github.com/rust-lang/rust/pull/37855
[37882]: https://github.com/rust-lang/rust/pull/37882
[37888]: https://github.com/rust-lang/rust/pull/37888
[37973]: https://github.com/rust-lang/rust/pull/37973
[37979]: https://github.com/rust-lang/rust/pull/37979
[38086]: https://github.com/rust-lang/rust/pull/38086
[38107]: https://github.com/rust-lang/rust/pull/38107
[38117]: https://github.com/rust-lang/rust/pull/38117
[38134]: https://github.com/rust-lang/rust/pull/38134
[38146]: https://github.com/rust-lang/rust/pull/38146
[38181]: https://github.com/rust-lang/rust/pull/38181
[38182]: https://github.com/rust-lang/rust/pull/38182
[38185]: https://github.com/rust-lang/rust/pull/38185
[38192]: https://github.com/rust-lang/rust/pull/38192
[38279]: https://github.com/rust-lang/rust/pull/38279
[38835]: https://github.com/rust-lang/rust/pull/38835
[RFC 1506]: https://github.com/rust-lang/rfcs/blob/master/text/1506-adt-kinds.md
[RFC 1560]: https://github.com/rust-lang/rfcs/blob/master/text/1560-name-resolution.md
[RFC 1681]: https://github.com/rust-lang/rfcs/blob/master/text/1681-macros-1.1.md
[RFC 1717]: https://github.com/rust-lang/rfcs/blob/master/text/1717-dllimport.md
[`hr_lifetime_in_assoc_type` lint]: https://github.com/rust-lang/rust/issues/33685
[`legacy_imports`]: https://github.com/rust-lang/rust/pull/38271
[cargo/3102]: https://github.com/rust-lang/cargo/pull/3102
[cargo/3221]: https://github.com/rust-lang/cargo/pull/3221
[cargo/3310]: https://github.com/rust-lang/cargo/pull/3310
[cargo/3311]: https://github.com/rust-lang/cargo/pull/3311
[cargo/3319]: https://github.com/rust-lang/cargo/pull/3319
[cargo/3336]: https://github.com/rust-lang/cargo/pull/3336
[cargo/3338]: https://github.com/rust-lang/cargo/pull/3338
[cargo/3348]: https://github.com/rust-lang/cargo/pull/3348
[cargo/3356]: https://github.com/rust-lang/cargo/pull/3356
[cargo/3361]: https://github.com/rust-lang/cargo/pull/3361
[cargo/3363]: https://github.com/rust-lang/cargo/pull/3363
[cargo/3368]: https://github.com/rust-lang/cargo/issues/3368
[cargo/3409]: https://github.com/rust-lang/cargo/pull/3409
[cargo/3410]: https://github.com/rust-lang/cargo/pull/3410
[`std::iter::Iterator::min_by`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.min_by
[`std::iter::Iterator::max_by`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.max_by
[`std::os::*::fs::FileExt`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html
[`std::sync::atomic::Atomic*::get_mut`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU8.html#method.get_mut
[`std::sync::atomic::Atomic*::into_inner`]: https://doc.rust-lang.org/std/sync/atomic/struct.AtomicU8.html#method.into_inner
[`std::vec::IntoIter::as_slice`]: https://doc.rust-lang.org/std/vec/struct.IntoIter.html#method.as_slice
[`std::vec::IntoIter::as_mut_slice`]: https://doc.rust-lang.org/std/vec/struct.IntoIter.html#method.as_mut_slice
[`std::sync::mpsc::Receiver::try_iter`]: https://doc.rust-lang.org/std/sync/mpsc/struct.Receiver.html#method.try_iter
[`std::os::unix::process::CommandExt::before_exec`]: https://doc.rust-lang.org/std/os/unix/process/trait.CommandExt.html#tymethod.before_exec
[`std::rc::Rc::strong_count`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.strong_count
[`std::rc::Rc::weak_count`]: https://doc.rust-lang.org/std/rc/struct.Rc.html#method.weak_count
[`std::sync::Arc::strong_count`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.strong_count
[`std::sync::Arc::weak_count`]: https://doc.rust-lang.org/std/sync/struct.Arc.html#method.weak_count
[`std::char::encode_utf8`]: https://doc.rust-lang.org/std/primitive.char.html#method.encode_utf8
[`std::char::encode_utf16`]: https://doc.rust-lang.org/std/primitive.char.html#method.encode_utf16
[`std::cell::Ref::clone`]: https://doc.rust-lang.org/std/cell/struct.Ref.html#method.clone
[`std::io::Take::into_inner`]: https://doc.rust-lang.org/std/io/struct.Take.html#method.into_inner
Version 1.14.0 (2016-12-22)
===========================
Language
--------
* [`..` matches multiple tuple fields in enum variants, structs
and tuples][36843]. [RFC 1492].
* [Safe `fn` items can be coerced to `unsafe fn` pointers][37389]
* [`use *` and `use ::*` both glob-import from the crate root][37367]
* [It's now possible to call a `Vec>` without explicit
dereferencing][36822]
Compiler
--------
* [Mark enums with non-zero discriminant as non-zero][37224]
* [Lower-case `static mut` names are linted like other
statics and consts][37162]
* [Fix ICE on some macros in const integer positions
(e.g. `[u8; m!()]`)][36819]
* [Improve error message and snippet for "did you mean `x`"][36798]
* [Add a panic-strategy field to the target specification][36794]
* [Include LLVM version in `--version --verbose`][37200]
Compile-time Optimizations
--------------------------
* [Improve macro expansion performance][37569]
* [Shrink `Expr_::ExprInlineAsm`][37445]
* [Replace all uses of SHA-256 with BLAKE2b][37439]
* [Reduce the number of bytes hashed by `IchHasher`][37427]
* [Avoid more allocations when compiling html5ever][37373]
* [Use `SmallVector` in `CombineFields::instantiate`][37322]
* [Avoid some allocations in the macro parser][37318]
* [Use a faster deflate setting][37298]
* [Add `ArrayVec` and `AccumulateVec` to reduce heap allocations
during interning of slices][37270]
* [Optimize `write_metadata`][37267]
* [Don't process obligation forest cycles when stalled][37231]
* [Avoid many `CrateConfig` clones][37161]
* [Optimize `Substs::super_fold_with`][37108]
* [Optimize `ObligationForest`'s `NodeState` handling][36993]
* [Speed up `plug_leaks`][36917]
Libraries
---------
* [`println!()`, with no arguments, prints newline][36825].
Previously, an empty string was required to achieve the same.
* [`Wrapping` impls standard binary and unary operators, as well as
the `Sum` and `Product` iterators][37356]
* [Implement `From> for String` and `From> for
Vec