-Version 1.54.0 (2021-06-29)
+Version 1.54.0 (2021-07-29)
============================
Language
-----------------------
-- [You can now use macros for values in key-value attributes.][83366]
+- [You can now use macros for values in built-in attribute macros.][83366]
While a seemingly minor addition on its own, this enables a lot of
powerful functionality when combined correctly. Most notably you can
now include external documentation in your crate by writing the following.
- [You can now cast between unsized slice types (and types which contain
unsized slices) in `const fn`.][85078]
-- [TODO: stabilize member constraints][84701]
+- [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
-----------------------
- [Improved debugger output for enums on Windows MSVC platforms.][85292]
- [Added tier 3\* support for `bpfel-unknown-none`
and `bpfeb-unknown-none`.][79608]
-- [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
-----------------------
-- [You can now explicitly import the prelude of different editions
- through `std::prelude`. (e.g. `use std::prelude::rust_2021::*;`)][86294]
- [`panic::panic_any` will now `#[track_caller]`.][85745]
- [Added `OutOfMemory` as a variant of `io::ErrorKind`.][84744]
- [ `proc_macro::Literal` now implements `FromStr`.][84717]
-- [TODO: Bump stdarch submodule][83278]
+- [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_values`]
- [`HashMap::into_keys`]
- [`HashMap::into_values`]
-- [`MaybeUninit::assume_init_mut`]
-- [`MaybeUninit::assume_init_ref`]
- [`arch::wasm32`]
-- [`arch::x86::_bittest`]
-- [`arch::x86::_bittestandcomplement`]
-- [`arch::x86::_bittestandset`]
-- [`arch::x86_64::_bittest`]
-- [`arch::x86_64::_bittestandcomplement64`]
-- [`arch::x86_64::_bittestandcomplement`]
-- [`arch::x86_64::_bittestandreset64`]
-- [`arch::x86_64::_bittestandset64`]
-- [`arch::x86_64::_bittestandset`]
-- [`ops::ControlFlow`]
- [`VecDeque::binary_search`]
- [`VecDeque::binary_search_by`]
- [`VecDeque::binary_search_by_key`]
- [`VecDeque::partition_point`]
Cargo
------------------------
+-----
- [Added the `--prune <spec>` option to `cargo-tree` to remove a package from
the dependency graph.][cargo/9520]
- [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.
-- [Configure hosts separately from targets when --target is specified.][cargo/9322]
-- [Respect Cargo.toml `[package.exclude]` even not in a git repo.][cargo/9186]
+Compatibility Notes
+-------------------
+- [Mixing Option and Result via `?` is no longer permitted in closures for inferred types.][86831]
+- [Previously unsound code is no longer permitted where different constructors in branches
+ could require different lifetimes.][85574]
+- As previously mentioned the [`std::arch` instrinsics now uses stricter const checking][83278]
+ than before and may reject some previously accepted code.
+- [`i128` multiplication on Cortex M0+ platforms currently unconditionally causes overflow
+ when compiled with `codegen-units = 1`.][86063]
+
+[85574]: https://github.com/rust-lang/rust/issues/85574
+[86831]: https://github.com/rust-lang/rust/issues/86831
+[86063]: https://github.com/rust-lang/rust/issues/86063
+[86831]: https://github.com/rust-lang/rust/issues/86831
[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
-[86294]: https://github.com/rust-lang/rust/pull/86294
[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
[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
-[83572]: https://github.com/rust-lang/rust/pull/83572
[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
-[cargo/9322]: https://github.com/rust-lang/cargo/pull/9322
-[cargo/9186]: https://github.com/rust-lang/cargo/pull/9186
-[`arch::x86::_bittest`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittest.html
-[`arch::x86::_bittestandcomplement`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittestandcomplement.html
-[`arch::x86::_bittestandset`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittestandset.html
-[`arch::x86_64::_bittest`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittest.html
-[`arch::x86_64::_bittestandcomplement64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandcomplement64.html
-[`arch::x86_64::_bittestandcomplement`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandcomplement.html
-[`arch::x86_64::_bittestandreset64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandreset64.html
-[`arch::x86_64::_bittestandset64`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandset64.html
-[`arch::x86_64::_bittestandset`]: https://doc.rust-lang.org/stable/core/arch/x86_64/fn._bittestandset.html
[`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
-[`MaybeUninit::assume_init_ref`]: https://doc.rust-lang.org/std/mem/union.MaybeUninit.html#method.assume_init_ref
-[`MaybeUninit::assume_init_mut`]: https://doc.rust-lang.org/std/mem/union.MaybeUninit.html#method.assume_init_mut
[`arch::wasm32`]: https://doc.rust-lang.org/core/arch/wasm32/index.html
-[`ops::ControlFlow`]: https://doc.rust-lang.org/std/ops/enum.ControlFlow.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
- [`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 RFC 754.][78618]
+ (`NaN`, `-0`) according to IEEE 754.][78618]
- [You can now index into slices using `(Bound<usize>, Bound<usize>)`.][77704]
- [Add the `BITS` associated constant to all numeric types.][82565]