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

Refer to Rust’s platform support page for more information on Rust’s tiered platform support.

Libraries¶

• Stabilize the anonymous pipe API

• Add support for unbounded left/right shift operations

• Print pointer metadata in Debug impl of raw pointers

• Vec::with_capacity guarantees it allocates with the amount requested, even if Vec::capacity returns a different number.

• Most std::arch intrinsics which don’t take pointer arguments can now be called from safe code if the caller has the appropriate target features already enabled (https://github.com/rust-lang/stdarch/pull/1714, https://github.com/rust-lang/stdarch/pull/1716, https://github.com/rust-lang/stdarch/pull/1717)

• Undeprecate env::home_dir

• Denote ControlFlow as #[must_use]

• Macros such as assert_eq! and vec! now support const {...} expressions

Stabilized APIs¶

• Vec::extract_if

• vec::ExtractIf

• LinkedList::extract_if

• linked_list::ExtractIf

• <[T]>::split_off

• <[T]>::split_off_mut

• <[T]>::split_off_first

• <[T]>::split_off_first_mut

• <[T]>::split_off_last

• <[T]>::split_off_last_mut

• String::extend_from_within

• os_str::Display

• OsString::display

• OsStr::display

• io::pipe

• io::PipeReader

• io::PipeWriter

• impl From<PipeReader> for OwnedHandle

• impl From<PipeWriter> for OwnedHandle

• impl From<PipeReader> for Stdio

• impl From<PipeWriter> for Stdio

• impl From<PipeReader> for OwnedFd

• impl From<PipeWriter> for OwnedFd

• Box<MaybeUninit<T>>::write

• impl TryFrom<Vec<u8>> for String

• <*const T>::offset_from_unsigned

• <*const T>::byte_offset_from_unsigned

• <*mut T>::offset_from_unsigned

• <*mut T>::byte_offset_from_unsigned

• NonNull::offset_from_unsigned

• NonNull::byte_offset_from_unsigned

• <uN>::cast_signed

• NonZero::<uN>::cast_signed.

• <iN>::cast_unsigned.

• NonZero::<iN>::cast_unsigned.

• <uN>::is_multiple_of

• <uN>::unbounded_shl

• <uN>::unbounded_shr

• <iN>::unbounded_shl

• <iN>::unbounded_shr

• <iN>::midpoint

• <str>::from_utf8

• <str>::from_utf8_mut

• <str>::from_utf8_unchecked

• <str>::from_utf8_unchecked_mut

These previously stable APIs are now stable in const contexts:

• core::str::from_utf8_mut

• <[T]>::copy_from_slice

• SocketAddr::set_ip

• SocketAddr::set_port,

• SocketAddrV4::set_ip

• SocketAddrV4::set_port,

• SocketAddrV6::set_ip

• SocketAddrV6::set_port

• SocketAddrV6::set_flowinfo

• SocketAddrV6::set_scope_id

• char::is_digit

• char::is_whitespace

• <[[T; N]]>::as_flattened

• <[[T; N]]>::as_flattened_mut

• String::into_bytes

• String::as_str

• String::capacity

• String::as_bytes

• String::len

• String::is_empty

• String::as_mut_str

• String::as_mut_vec

• Vec::as_ptr

• Vec::as_slice

• Vec::capacity

• Vec::len

• Vec::is_empty

• Vec::as_mut_slice

• Vec::as_mut_ptr

Cargo¶

• Add terminal integration via ANSI OSC 9;4 sequences

• chore: bump openssl to v3

• feat(package): add –exclude-lockfile flag

Compatibility Notes¶

• Rust now raises an error for macro invocations inside the #![crate_name] attribute

• Unstable fields are now always considered to be inhabited

• Macro arguments of unary operators followed by open beginning ranges may now be matched differently

• Make Debug impl of raw pointers print metadata if present

• Warn against function pointers using unsupported ABI strings in dependencies

• Associated types on dyn types are no longer deduplicated

• Forbid attributes on .. inside of struct patterns (let Struct { #[attribute] .. }) =

• Make ptr_cast_add_auto_to_object lint into hard error

• Many std::arch intrinsics are now safe to call in some contexts, there may now be new unused_unsafe warnings in existing codebases.

• Limit width and precision formatting options to 16 bits on all targets

• Turn order dependent trait objects future incompat warning into a hard error

• Denote ControlFlow as #[must_use]

• Windows: The standard library no longer links advapi32, except on win7. Code such as C libraries that were relying on this assumption may need to explicitly link advapi32.

• Proc macros can no longer observe expanded cfg(true) attributes.

• Start changing the internal representation of pasted tokens. Certain invalid declarative macros that were previously accepted in obscure circumstances are now correctly rejected by the compiler. Use of a tt fragment specifier can often fix these macros.

• Don’t allow flattened format_args in const.

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.

• Update to LLVM 20

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-stabilize the #[bench] attribute. Usage of #[bench] without #![feature(custom_test_frameworks)] already triggered a deny-by-default future-incompatibility lint since Rust 1.77, but will now become a hard error.

• Add warn-by-default dangerous_implicit_autorefs lint against implicit autoref of raw pointer dereference. The lint will be bumped to deny-by-default in the next version of Rust.

• Add invalid_null_arguments lint to prevent invalid usage of null pointers. This lint is uplifted from clippy::invalid_null_ptr_usage.

• Change trait impl candidate preference for builtin impls and trivial where-clauses.

• Check types of generic const parameter defaults

Compiler¶

• Stabilize -Cdwarf-version for selecting the version of DWARF debug information to generate.

Platform Support¶

• Demote i686-pc-windows-gnu to Tier 2.

Refer to Rust’s platform support page for more information on Rust’s tiered platform support.

Libraries¶

• Remove backticks from #[should_panic] test failure message.

• Guarantee that [T; N]::from_fn is generated in order of increasing indices., for those passing it a stateful closure.

• The libtest flag --nocapture is deprecated in favor of the more consistent --no-capture flag.

• Guarantee that {float}::NAN is a quiet NaN.

Stabilized APIs¶

• Cell::update

• impl Default for *const T

• impl Default for *mut T

• HashMap::extract_if

• HashSet::extract_if

• hint::select_unpredictable

• proc_macro::Span::line

• proc_macro::Span::column

• proc_macro::Span::start

• proc_macro::Span::end

• proc_macro::Span::file

• proc_macro::Span::local_file

• <[T]>::as_chunks

• <[T]>::as_chunks_mut

• <[T]>::as_chunks_unchecked

• <[T]>::as_chunks_unchecked_mut

• <[T]>::as_rchunks

• <[T]>::as_rchunks_mut

• mod ffi::c_str

These previously stable APIs are now stable in const contexts:

• NonNull<T>::replace

• <*mut T>::replace

• std::ptr::swap_nonoverlapping

• Cell::replace

• Cell::get

• Cell::get_mut

• Cell::from_mut

• Cell::as_slice_of_cells

Cargo¶

• Stabilize automatic garbage collection.

• use zlib-rs for gzip compression in rust code

Rustdoc¶

• Doctests can be ignored based on target names using ignore-* attributes.

• Stabilize the --test-runtool and --test-runtool-arg CLI options to specify a program (like qemu) and its arguments to run a doctest.

Compatibility Notes¶

• Finish changing the internal representation of pasted tokens. Certain invalid declarative macros that were previously accepted in obscure circumstances are now correctly rejected by the compiler. Use of a tt fragment specifier can often fix these macros.

• Fully de-stabilize the #[bench] attribute. Usage of #[bench] without #![feature(custom_test_frameworks)] already triggered a deny-by-default future-incompatibility lint since Rust 1.77, but will now become a hard error.

• Fix borrow checking some always-true patterns. The borrow checker was overly permissive in some cases, allowing programs that shouldn’t have compiled.

• Update the minimum external LLVM to 19.

• Make it a hard error to use a vector type with a non-Rust ABI without enabling the required target feature.