1.77.0 #

• Released on: 21 March, 2024
• Branched from master on: 2 February, 2024

Language #

• Reveal opaque types within the defining body for exhaustiveness checking.
• Stabilize C-string literals.
• Stabilize THIR unsafeck.
• Add lint static_mut_refs to warn on references to mutable statics.
• Support async recursive calls (as long as they have indirection).
• Undeprecate lint unstable_features and make use of it in the compiler.
• Make inductive cycles in coherence ambiguous always.
• Get rid of type-driven traversal in const-eval interning, only as a future compatiblity lint for now.
• Deny braced macro invocations in let-else.

Compiler #

• Include lint soft_unstable in future breakage reports.
• Make i128 and u128 16-byte aligned on x86-based targets.
• Use --verbose in diagnostic output.
• Improve spacing between printed tokens.
• Merge the unused_tuple_struct_fields lint into dead_code.
• Error on incorrect implied bounds in well-formedness check, with a temporary exception for Bevy.
• Fix coverage instrumentation/reports for non-ASCII source code.
• Fix fn/const items implied bounds and well-formedness check.
• Promote riscv32{im|imafc}-unknown-none-elf targets to tier 2.
• Add several new tier 3 targets:
  • aarch64-unknown-illumos
  • hexagon-unknown-none-elf
  • riscv32imafc-esp-espidf
  • riscv32im-risc0-zkvm-elf

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]>.
• Remove special-case handling of vec.split_off(0).

Stabilized APIs #

• array::each_ref
• array::each_mut
• core::net
• f32::round_ties_even
• f64::round_ties_even
• mem::offset_of!
• slice::first_chunk
• slice::first_chunk_mut
• slice::split_first_chunk
• slice::split_first_chunk_mut
• slice::last_chunk
• slice::last_chunk_mut
• slice::split_last_chunk
• slice::split_last_chunk_mut
• slice::chunk_by
• slice::chunk_by_mut
• Bound::map
• File::create_new
• Mutex::clear_poison
• RwLock::clear_poison

Cargo #

• Extend the build directive syntax with cargo::.
• Stabilize metadata id format as PackageIDSpec.
• Pull out cargo-util-schemas as a crate.
• Strip all debuginfo when debuginfo is not requested.
• Inherit jobserver from env for all kinds of runners.
• Deprecate rustc plugin support in cargo.

Rustdoc #

• Allows links in markdown headings.
• Search for tuples and unit by type with ().
• Clean up the source sidebar’s hide button.
• Prevent JS injection from localStorage.

Misc #

• Recommend version-sorting for all sorting in style guide.

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.