1.75.0 #

• Released on: 28 December, 2023
• Branched from master on: 10 November, 2023

Language #

• Stabilize async fn and return-position impl Trait in traits.
• Allow function pointer signatures containing &mut T in const contexts.
• Match usize/isize exhaustively with half-open ranges.
• Guarantee that char has the same size and alignment as u32.
• Document that the null pointer has the 0 address.
• Allow partially moved values in match.
• Add notes about non-compliant FP behavior on 32bit x86 targets.
• Stabilize ratified RISC-V target features.

Compiler #

• Rework negative coherence to properly consider impls that only partly overlap.
• Bump COINDUCTIVE_OVERLAP_IN_COHERENCE to deny, and warn in dependencies.
• Consider alias bounds when computing liveness in NLL.
• Add the V (vector) extension to the riscv64-linux-android target spec.
• Automatically enable cross-crate inlining for small functions
• Add several new tier 3 targets:
  • csky-unknown-linux-gnuabiv2hf
  • i586-unknown-netbsd
  • mipsel-unknown-netbsd

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 Wakers unnecessarily.
• Implement BufRead for VecDeque<u8>.
• Implement FusedIterator for DecodeUtf16 when the inner iterator does.
• Implement Not, Bit{And,Or}{,Assign} for IP addresses.
• Implement Default for ExitCode.
• Guarantee representation of None in NPO
• Document when atomic loads are guaranteed read-only.
• Broaden the consequences of recursive TLS initialization.
• Windows: Support sub-millisecond sleep.
• Fix generic bound of str::SplitInclusive’s DoubleEndedIterator impl
• Fix exit status / wait status on non-Unix cfg(unix) platforms.

Stabilized APIs #

• Atomic*::from_ptr
• FileTimes
• FileTimesExt
• File::set_modified
• File::set_times
• IpAddr::to_canonical
• Ipv6Addr::to_canonical
• Option::as_slice
• Option::as_mut_slice
• pointer::byte_add
• pointer::byte_offset
• pointer::byte_offset_from
• pointer::byte_sub
• pointer::wrapping_byte_add
• pointer::wrapping_byte_offset
• pointer::wrapping_byte_sub

These APIs are now stable in const contexts:

• Ipv6Addr::to_ipv4_mapped
• MaybeUninit::assume_init_read
• MaybeUninit::zeroed
• mem::discriminant
• mem::zeroed

Cargo #

• Add new packages to [workspace.members] automatically.
• Allow version-less Cargo.toml manifests.
• Make browser links out of HTML file paths.

Rustdoc #

• Accept less invalid Rust in rustdoc.
• Document lack of object safety on affected traits.
• Hide #[repr(transparent)] if it isn’t part of the public ABI.
• Show enum discriminant if it is a C-like variant.

Compatibility Notes #

• FreeBSD targets now require at least version 12.
• Formally demote tier 2 MIPS targets to tier 3.
• Make misalignment a hard error in const contexts.
• Fix detecting references to packed unsized fields.
• Remove support for compiler plugins.

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.
• Enable parallel rustc front end in dev and nightly builds.
• Distribute rustc-codegen-cranelift as rustup component on the nightly channel.