Rust 1.51.0

Language

--------

- [You can now parameterize items such as functions, traits, and structs 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.

  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