Rust

Language

• Stabilize explicitly inferred const arguments (feature(generic_arg_infer))
• Add a warn-by-default mismatched_lifetime_syntaxes lint. This lint detects when the same lifetime is referred to by different syntax categories between function arguments and return values, which can be confusing to read, especially in unsafe code. This lint supersedes the warn-by-default elided_named_lifetimes lint.
• Expand unpredictable_function_pointer_comparisons to also lint on function pointer comparisons in external macros
• Make the dangerous_implicit_autorefs lint deny-by-default
• Stabilize the avx512 target features
• Stabilize kl and widekl<

Language

• Stabilize #![feature(let_chains)] in the 2024 edition. This feature allows &&-chaining let statements inside if and while, allowing intermixture with boolean expressions. The patterns inside the let sub-expressions can be irrefutable or refutable.
• Stabilize #![feature(naked_functions)]. Naked functions allow writing functions with no compiler-generated epilogue and prologue, allowing full control over the generated assembly for a particular function.
• Stabilize #![feature(cfg_boolean_literals)]. This allows using boolean literals as cfg predicates, e.g. #[cfg(true)] and #[cfg(false)].
• Fully de-s

Language

• Stabilize asm_goto feature
• Allow parsing open beginning ranges (..EXPR) after unary operators !, -, and *.
• Don't require method impls for methods with Self: Sized bounds in impls for unsized types
• Stabilize feature(precise_capturing_in_traits) allowing use<...> bounds on return position impl Trait in traits

Compiler

• x86: make SSE2 required for i686 targets and use it to pass SIMD types

Platform Support

• Remove i586-pc-windows-msvc target

R

Language

• Stabilize upcasting trait objects to supertraits.
• Allow safe functions to be marked with the #[target_feature] attribute.
• The missing_abi lint now warns-by-default.
• Rust now lints about double negations, to catch cases that might have intended to be a prefix decrement operator (--x) as written in other languages. This was previously a clippy lint, clippy::double_neg, and is now available directly in Rust as double_negations.
• More pointers are now detected as definitely not-null based on their alignment in const eval.
• Empty repr() attribute applied to invalid items are now correctly rejected.
• Inner attrib

• Fix the doctest-merging feature of the 2024 Edition.
• Relax some target_feature checks when generating docs.
• Fix errors in std::fs::rename on Windows 10, version 1607.
• Downgrade bootstrap cc to fix custom targets.
• Skip submodule updates when building Rust from a source tarball.

Language

• The 2024 Edition is now stable. See the edition guide for more details.
• Stabilize async closures See RFC 3668 for more details.
• Stabilize #[diagnostic::do_not_recommend]
• Add unpredictable_function_pointer_comparisons lint to warn against function pointer comparisons
• Lint on combining #[no_mangle] and #[export_name] attributes.

Compiler

• The unstable flag -Zpolymorphize has been removed, see rust-lang/compiler-team#810 for some background.

Platform Support

• Promote powerpc64le-unknown-linu

• Fix ICE 132920 in duplicate-crate diagnostics.
• Fix errors for overlapping impls in incremental rebuilds.
• Fix slow compilation related to the next-generation trait solver.
• Fix debuginfo when LLVM's location discriminator value limit is exceeded.
• Fixes for building Rust from source:
  • Only try to distribute llvm-objcopy if llvm tools are enabled.
  • Add Profile Override for Non-Git Sources.
  • Resolve symlinks of LLVM tool binaries before copying them.
  • Make it possible to use ci-rustc on tarball sources.

Language

• Allow #[deny] inside #[forbid] as a no-op
• Show a warning when -Ctarget-feature is used to toggle features that can lead to unsoundness due to ABI mismatches
• Use the next-generation trait solver in coherence
• Allow coercions to drop the principal of trait objects
• Support / as the path separator for include!() in all cases on Windows
• Taking a raw ref (raw (const|mut)) of a deref of a pointer (*ptr) is now safe
• Stabilize s390x inline assembly
• Stabilize Arm64EC inline assembly
• Lint against creating pointers to immediately dropped temporaries

Language

• Stabilize &mut, *mut, &Cell, and *const Cell in const.
• Allow creating references to statics in const initializers.
• Implement raw lifetimes and labels ('r#ident).
• Define behavior when atomic and non-atomic reads race.
• Non-exhaustive structs may now be empty.
• Disallow implicit coercions from places of type !
• const extern functions can now be defined for other calling conventions.
• Stabilize expr_2021 macro fragment specifier in all editions.
• The non_local_definitions lint now fires on less code and warns b

Language

• Don't make statement nonterminals match pattern nonterminals
• Patterns matching empty types can now be omitted in common cases
• Enforce supertrait outlives obligations when using trait impls
• addr_of(_mut)! macros and the newly stabilized &raw (const|mut) are now safe to use with all static items
• size_of_val_raw: for length 0 this is safe to call
• Reorder trait bound modifiers after for<...> binder in trait bounds
• Stabilize opaque type precise capturing (RFC 3617)
• Stabilize &raw const and &raw mut operators (RFC 2582)
• Stabilize unsafe extern blocks (RF

Language

• Abort on uncaught panics in extern "C" functions.
• Fix ambiguous cases of multiple & in elided self lifetimes.
• Stabilize #[expect] for lints (RFC 2383), like #[allow] with a warning if the lint is not fulfilled.
• Change method resolution to constrain hidden types instead of rejecting method candidates.
• Bump elided_lifetimes_in_associated_constant to deny.
• offset_from: always allow pointers to point to the same address.
• Allow constraining opaque types during subtyping in the trait system.
• Allow constraining opaque types during various unsizing casts.