Rust 1.94.0

Language

• Impls and impl items inherit dead_code lint level of the corresponding traits and trait items
• Stabilize additional 29 RISC-V target features including large portions of the RVA22U64 / RVA23U64 profiles
• Add warn-by-default unused_visibilities lint for visibility on const _ declarations
• Update to Unicode 17
• Avoid incorrect lifetime errors for closures

Platform Support

• Add riscv64im-unknown-none-elf as a tier 3 target

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

Libraries

• Relax T: Ord bound for some BinaryHeap<T> methods.

Stabilized APIs

• <[T]>::array_windows
• <[T]>::element_offset
• LazyCell::get
• LazyCell::get_mut
• LazyCell::force_mut
• LazyLock::get
• LazyLock::get_mut
• LazyLock::force_mut
• impl TryFrom<char> for usize
• std::iter::Peekable::next_if_map
• std::iter::Peekable::next_if_map_mut
• x86 avx512fp16 intrinsics (excluding those that depend directly on the unstable f16 type)
• AArch64 NEON fp16 intrinsics (excluding those that depend directly on the unstable f16 type)
• f32::consts::EULER_GAMMA
• f64::consts::EULER_GAMMA
• f32::consts::GOLDEN_RATIO
• f64::consts::GOLDEN_RATIO

These previously stable APIs are now stable in const contexts:

• f32::mul_add
• f64::mul_add

Cargo

• Stabilize the config include key. The top-level include config key allows loading additional config files, enabling better organization, sharing, and management of Cargo configurations across projects and environments. docs #16284
• Stabilize the pubtime field in registry index. This records when a crate version was published and enables time-based dependency resolution in the future. Note that crates.io will gradually backfill existing packages when a new version is published. Not all crates have pubtime yet. #16369 #16372
• Cargo now parses TOML v1.1 for manifests and configuration files. Note that using these features in Cargo.toml will raise your development MSRV, but the published manifest remains compatible with older parsers. #16415
• Make CARGO_BIN_EXE_<crate> available at runtime

Compatibility Notes

• Forbid freely casting lifetime bounds of dyn-types
• Make closure capturing have consistent and correct behaviour around patterns Some finer details of how precise closure captures get affected by pattern matching have been changed. In some cases, this can cause a non-move closure that was previously capturing an entire variable by move, to now capture only part of that variable by move, and other parts by borrow. This can cause the borrow checker to complain where it previously didn't, or cause Drop to run at a different point in time.
• Standard library macros are now imported via prelude, not via injected #[macro_use] This will raise an error if macros of the same name are glob imported. For example if a crate defines their own matches macro and then glob imports that, it's now ambiguous whether the custom or standard library matches is meant and an explicit import of the name is required to resolve the ambiguity. One exception is core::panic and std::panic, if their import is ambiguous a new warning (ambiguous_panic_imports) is raised. This may raise a new warning (ambiguous_panic_imports) on #![no_std] code glob importing the std crate. Both core::panic! and std::panic! are then in scope and which is used is ambiguous.
• Don't strip shebang in expression-context include!(…)s This can cause previously working includes to no longer compile if they included files which started with a shebang.
• Ambiguous glob reexports are now also visible cross-crate This unifies behavior between local and cross-crate errors on these exports, which may introduce new ambiguity errors.
• Don't normalize where-clauses before checking well-formedness
• Introduce a future compatibility warning on codegen attributes on body-free trait methods These attributes currently have no effect in this position.
• On Windows std::time::SystemTime::checked_sub_duration will return None for times before the Windows epoch (1/1/1601)
• Lifetime identifiers such as 'a are now NFC normalized.
• Overhaul filename handling for cross-compiler consistency Any paths emitted by compiler now always respect the relative-ness of the paths and --remap-path-prefix given originally. One side-effect of this change is that paths emitted for local crates in Cargo (path dependencies and workspace members) are no longer absolute but relative when emitted as part of a diagnostic in a downstream crate.

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.

• Switch to annotate-snippets for error emission This should preserve mostly the same outputs in rustc error messages.

Rust 1.93.1

• Don't try to recover keyword as non-keyword identifier, fixing an ICE that especially affected rustfmt.
• Fix clippy::panicking_unwrap false-positive on field access with implicit deref.
• Revert "Update wasm-related dependencies in CI", fixing file descriptor leaks on the wasm32-wasip2 target.

Rust 1.93.0

Language

• Stabilize several s390x vector-related target features and the is_s390x_feature_detected! macro
• Stabilize declaration of C-style variadic functions for the system ABI
• Emit error when using some keyword as a cfg predicate
• Stabilize asm_cfg
• During const-evaluation, support copying pointers byte-by-byte
• LUB coercions now correctly handle function item types, and functions with differing safeties
• Allow const items that contain mutable references to static (which is very unsafe, but not always UB)
• Add warn-by-default const_item_interior_mutations lint to warn against calls which mutate interior mutable const items
• Add warn-by-default function_casts_as_integer lint

Compiler

• Stabilize -Cjump-tables=bool. The flag was previously called -Zno-jump-tables.

Platform Support

• Promote riscv64a23-unknown-linux-gnu to Tier 2 (without host tools)

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

Libraries

• Stop internally using specialization on the Copy trait as it is unsound in the presence of lifetime dependent Copy implementations. This may result in some performance regressions as some standard library APIs may now call Clone::clone instead of performing bitwise copies
• Allow the global allocator to use thread-local storage and std::thread::current()
• Make BTree::append not update existing keys when appending an entry which already exists
• Don't require T: RefUnwindSafe for vec::IntoIter<T>: UnwindSafe

Stabilized APIs

• <[MaybeUninit<T>]>::assume_init_drop
• <[MaybeUninit<T>]>::assume_init_ref
• <[MaybeUninit<T>]>::assume_init_mut
• <[MaybeUninit<T>]>::write_copy_of_slice
• <[MaybeUninit<T>]>::write_clone_of_slice
• String::into_raw_parts
• Vec::into_raw_parts
• <iN>::unchecked_neg
• <iN>::unchecked_shl
• <iN>::unchecked_shr
• <uN>::unchecked_shl
• <uN>::unchecked_shr
• <[T]>::as_array
• <[T]>::as_mut_array
• <*const [T]>::as_array
• <*mut [T]>::as_mut_array
• VecDeque::pop_front_if
• VecDeque::pop_back_if
• Duration::from_nanos_u128
• char::MAX_LEN_UTF8
• char::MAX_LEN_UTF16
• std::fmt::from_fn
• std::fmt::FromFn

Cargo

• Enable CARGO_CFG_DEBUG_ASSERTIONS in build scripts based on profile
• In cargo tree, support long forms for --format variables
• Add --workspace to cargo clean

Rustdoc

• Remove #![doc(document_private_items)]
• Include attribute and derive macros in search filters for "macros"
• Include extern crates in search filters for import
• Validate usage of crate-level doc attributes. This means if any of html_favicon_url, html_logo_url, html_playground_url, issue_tracker_base_url, or html_no_source either has a missing value, an unexpected value, or a value of the wrong type, rustdoc will emit the deny-by-default lint rustdoc::invalid_doc_attributes.

Compatibility Notes

• Introduce pin_v2 into the builtin attributes namespace
• Update bundled musl to 1.2.5
• On Emscripten, the unwinding ABI used when compiling with panic=unwind was changed from the JS exception handling ABI to the wasm exception handling ABI. If linking C/C++ object files with Rust objects, -fwasm-exceptions must be passed to the linker now. On nightly Rust, it is possible to get the old behavior with -Zwasm-emscripten-eh=false -Zbuild-std, but it will be removed in a future release.
• The #[test] attribute, used to define tests, was previously ignored in various places where it had no meaning (e.g on trait methods or types). Putting the #[test] attribute in these places is no longer ignored, and will now result in an error; this may also result in errors when generating rustdoc. Error when test attribute is applied to structs
• Cargo now sets the CARGO_CFG_DEBUG_ASSERTIONS environment variable in more situations. This will cause crates depending on static-init versions 1.0.1 to 1.0.3 to fail compilation with "failed to resolve: use of unresolved module or unlinked crate parking_lot". See the linked issue for details.
• User written types in the offset_of! macro are now checked to be well formed.
• cargo publish no longer emits .crate files as a final artifact for user access when the build.build-dir config is unset
• Upgrade the deref_nullptr lint from warn-by-default to deny-by-default
• Add future-incompatibility warning for ... function parameters without a pattern outside of extern blocks
• Introduce future-compatibility warning for repr(C) enums whose discriminant values do not fit into a c_int or c_uint
• Introduce future-compatibility warning against ignoring repr(C) types as part of repr(transparent)

Rust 1.92.0

Language

• Document MaybeUninit representation and validity
• Allow &raw [mut | const] for union field in safe code
• Prefer item bounds of associated types over where-bounds for auto-traits and Sized
• Do not materialize X in [X; 0] when X is unsizing a const
• Support combining #[track_caller] and #[no_mangle] (requires every declaration specifying #[track_caller] as well)
• Make never type lints never_type_fallback_flowing_into_unsafe and dependency_on_unit_never_type_fallback deny-by-default
• Allow specifying multiple bounds for same associated item, except in trait objects
• Slightly strengthen higher-ranked region handling in coherence
• The unused_must_use lint no longer warns on Result<(), Uninhabited> (for instance, Result<(), !>), or ControlFlow<Uninhabited, ()>. This avoids having to check for an error that can never happen.

Compiler

• Make mips64el-unknown-linux-muslabi64 link dynamically
• Remove current code for embedding command-line args in PDB Command-line information is typically not needed by debugging tools, and the removed code was causing problems for incremental builds even on targets that don't use PDB debuginfo.

Libraries

• Specialize Iterator::eq{_by} for TrustedLen iterators
• Simplify Extend for tuples
• Added details to Debug for EncodeWide.
• iter::Repeat::last and count will now panic, rather than looping infinitely.

Stabilized APIs

• NonZero<u{N}>::div_ceil
• Location::file_as_c_str
• RwLockWriteGuard::downgrade
• Box::new_zeroed
• Box::new_zeroed_slice
• Rc::new_zeroed
• Rc::new_zeroed_slice
• Arc::new_zeroed
• Arc::new_zeroed_slice
• btree_map::Entry::insert_entry
• btree_map::VacantEntry::insert_entry
• impl Extend<proc_macro::Group> for proc_macro::TokenStream
• impl Extend<proc_macro::Literal> for proc_macro::TokenStream
• impl Extend<proc_macro::Punct> for proc_macro::TokenStream
• impl Extend<proc_macro::Ident> for proc_macro::TokenStream

These previously stable APIs are now stable in const contexts:

• <[_]>::rotate_left
• <[_]>::rotate_right

Cargo

• Added a new chapter to the Cargo book, "Optimizing Build Performance".

Rustdoc

• If a trait item appears in rustdoc search, hide the corresponding impl items. Previously a search for "last" would show both Iterator::last as well as impl methods like std::vec::IntoIter::last. Now these impl methods will be hidden, freeing up space for inherent methods like BTreeSet::last.
• Relax rules for identifiers in search. Previously you could only search for identifiers that were valid in rust code, now searches only need to be valid as part of an identifier. For example, you can now perform a search that starts with a digit.

Compatibility Notes

• Fix backtraces with -C panic=abort on Linux by generating unwind tables by default. Build with -C force-unwind-tables=no to keep omitting unwind tables.

• As part of the larger effort refactoring compiler built-in attributes and their diagnostics, the future-compatibility lint invalid_macro_export_arguments is upgraded to deny-by-default and will be reported in dependencies too.
• Update the minimum external LLVM to 20
• Prevent downstream impl DerefMut for Pin<LocalType>
• Don't apply temporary lifetime extension rules to the arguments of non-extended pin! and formatting macros

Rust 1.91.1

• Enable file locking support in illumos. This fixes Cargo not locking the build directory on illumos.
• Fix wasm_import_module attribute cross-crate. This fixes linker errors on WASM targets.

Rust 1.91.0

Language

• Lower pattern bindings in the order they're written and base drop order on primary bindings' order
• Stabilize declaration of C-style variadic functions for sysv64, win64, efiapi, and aapcs ABIs. This brings these ABIs in line with the C ABI: variadic functions can be declared in extern blocks but not defined.
• Add dangling_pointers_from_locals lint to warn against dangling pointers from local variables
• Upgrade semicolon_in_expressions_from_macros from warn to deny
• Stabilize LoongArch32 inline assembly
• Add warn-by-default integer_to_ptr_transmutes lint against integer-to-pointer transmutes
• Stabilize sse4a and tbm target features
• Add target_env = "macabi" and target_env = "sim" cfgs as replacements for the target_abi cfgs with the same values.

Compiler

• Don't warn on never-to-any as casts as unreachable

Platform Support

• Promote aarch64-pc-windows-gnullvm and x86_64-pc-windows-gnullvm to Tier 2 with host tools. Note: llvm-tools and MSI installers are missing but will be added in future releases.
• Promote aarch64-pc-windows-msvc to Tier 1

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

Libraries

• Print thread ID in panic message
• Fix overly restrictive lifetime in core::panic::Location::file return type
• Guarantee parameter order for _by() variants of min / max/ minmax in std::cmp
• Document assumptions about Clone and Eq traits
• std::thread: Return error if setting thread stack size fails This used to panic within the standard library.

Stabilized APIs

• Path::file_prefix
• AtomicPtr::fetch_ptr_add
• AtomicPtr::fetch_ptr_sub
• AtomicPtr::fetch_byte_add
• AtomicPtr::fetch_byte_sub
• AtomicPtr::fetch_or
• AtomicPtr::fetch_and
• AtomicPtr::fetch_xor
• {integer}::strict_add
• {integer}::strict_sub
• {integer}::strict_mul
• {integer}::strict_div
• {integer}::strict_div_euclid
• {integer}::strict_rem
• {integer}::strict_rem_euclid
• {integer}::strict_neg
• {integer}::strict_shl
• {integer}::strict_shr
• {integer}::strict_pow
• i{N}::strict_add_unsigned
• i{N}::strict_sub_unsigned
• i{N}::strict_abs
• u{N}::strict_add_signed
• u{N}::strict_sub_signed
• PanicHookInfo::payload_as_str
• core::iter::chain
• u{N}::checked_signed_diff
• core::array::repeat
• PathBuf::add_extension
• PathBuf::with_added_extension
• Duration::from_mins
• Duration::from_hours
• impl PartialEq<str> for PathBuf
• impl PartialEq<String> for PathBuf
• impl PartialEq<str> for Path
• impl PartialEq<String> for Path
• impl PartialEq<PathBuf> for String
• impl PartialEq<Path> for String
• impl PartialEq<PathBuf> for str
• impl PartialEq<Path> for str
• Ipv4Addr::from_octets
• Ipv6Addr::from_octets
• Ipv6Addr::from_segments
• impl<T> Default for Pin<Box<T>> where Box<T>: Default, T: ?Sized
• impl<T> Default for Pin<Rc<T>> where Rc<T>: Default, T: ?Sized
• impl<T> Default for Pin<Arc<T>> where Arc<T>: Default, T: ?Sized
• Cell::as_array_of_cells
• u{N}::carrying_add
• u{N}::borrowing_sub
• u{N}::carrying_mul
• u{N}::carrying_mul_add
• BTreeMap::extract_if
• BTreeSet::extract_if
• impl Debug for windows::ffi::EncodeWide<'_>
• str::ceil_char_boundary
• str::floor_char_boundary
• impl Sum for Saturating<u{N}>
• impl Sum<&Self> for Saturating<u{N}>
• impl Product for Saturating<u{N}>
• impl Product<&Self> for Saturating<u{N}>

These previously stable APIs are now stable in const contexts:

• [<[T; N]>::each_ref](https://doc.rust-lang.org/stable/std/...

Rust 1.90.0

Language

• Split up the unknown_or_malformed_diagnostic_attributes lint. This lint has been split up into four finer-grained lints, with unknown_or_malformed_diagnostic_attributes now being the lint group that contains these lints:
  1. unknown_diagnostic_attributes: unknown to the current compiler
  2. misplaced_diagnostic_attributes: placed on the wrong item
  3. malformed_diagnostic_attributes: malformed attribute syntax or options
  4. malformed_diagnostic_format_literals: malformed format string literal
• Allow constants whose final value has references to mutable/external memory, but reject such constants as patterns
• Allow volatile access to non-Rust memory, including address 0

Compiler

• Use lld by default on x86_64-unknown-linux-gnu.
• Tier 3 musl targets now link dynamically by default. Affected targets:
  • mips64-unknown-linux-muslabi64
  • powerpc64-unknown-linux-musl
  • powerpc-unknown-linux-musl
  • powerpc-unknown-linux-muslspe
  • riscv32gc-unknown-linux-musl
  • s390x-unknown-linux-musl
  • thumbv7neon-unknown-linux-musleabihf

Platform Support

• Demote x86_64-apple-darwin to Tier 2 with host tools

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

Libraries

• Stabilize u*::{checked,overflowing,saturating,wrapping}_sub_signed
• Allow comparisons between CStr, CString, and Cow<CStr>
• Remove some unsized tuple impls since unsized tuples can't be constructed
• Set MSG_NOSIGNAL for UnixStream
• proc_macro::Ident::new now supports $crate.
• Guarantee the pointer returned from Thread::into_raw has at least 8 bytes of alignment

Stabilized APIs

• u{n}::checked_sub_signed
• u{n}::overflowing_sub_signed
• u{n}::saturating_sub_signed
• u{n}::wrapping_sub_signed
• impl Copy for IntErrorKind
• impl Hash for IntErrorKind
• impl PartialEq<&CStr> for CStr
• impl PartialEq<CString> for CStr
• impl PartialEq<Cow<CStr>> for CStr
• impl PartialEq<&CStr> for CString
• impl PartialEq<CStr> for CString
• impl PartialEq<Cow<CStr>> for CString
• impl PartialEq<&CStr> for Cow<CStr>
• impl PartialEq<CStr> for Cow<CStr>
• impl PartialEq<CString> for Cow<CStr>

These previously stable APIs are now stable in const contexts:

• <[T]>::reverse
• f32::floor
• f32::ceil
• f32::trunc
• f32::fract
• f32::round
• f32::round_ties_even
• f64::floor
• f64::ceil
• f64::trunc
• f64::fract
• f64::round
• f64::round_ties_even

Cargo

• Add http.proxy-cainfo config for proxy certs
• Use gix for cargo package
• feat(publish): Stabilize multi-package publishing

Rustdoc

• Add ways to collapse all impl blocks. Previously the "Summary" button and "-" keyboard shortcut would never collapse impl blocks, now they do when shift is held
• Display unsafe attributes with unsafe() wrappers

Compatibility Notes

• Use lld by default on x86_64-unknown-linux-gnu. See also https://blog.rust-lang.org/2025/09/01/rust-lld-on-1.90.0-stable/.
• Make core::iter::Fuse's Default impl construct I::default() internally as promised in the docs instead of always being empty
• Set MSG_NOSIGNAL for UnixStream This may change program behavior but results in the same behavior as other primitives (e.g., stdout, network sockets). Programs relying on signals to terminate them should update handling of sockets to handle errors on write by exiting.
• On Unix std::env::home_dir will use the fallback if the HOME environment variable is empty
• We now reject unsupported extern "{abi}"s consistently in all positions. This primarily affects the use of implementing traits on an extern "{abi}" function pointer, like extern "stdcall" fn(), on a platform that doesn't support that, like aarch64-unknown-linux-gnu. Direct usage of these unsupported ABI strings by declaring or defining functions was already rejected, so this is only a change for consistency.
• const-eval: error when initializing a static writes to that static
• Check that the proc_macro_derive macro has correct arguments when applied to the crate root

Rust 1.89.0

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 target features for x86
• Stabilize sha512, sm3 and sm4 target features for x86
• Stabilize LoongArch target features f, d, frecipe, lasx, lbt, lsx, and lvz
• Remove i128 and u128 from improper_ctypes_definitions
• Stabilize repr128 (#[repr(u128)], #[repr(i128)])
• Allow #![doc(test(attr(..)))] everywhere
• Extend temporary lifetime extension to also go through tuple struct and tuple variant constructors
• extern "C" functions on the wasm32-unknown-unknown target now have a standards compliant ABI

Compiler

• Default to non-leaf frame pointers on aarch64-linux
• Enable non-leaf frame pointers for Arm64EC Windows
• Set Apple frame pointers by architecture

Platform Support

• Add new Tier-3 targets loongarch32-unknown-none and loongarch32-unknown-none-softfloat
• x86_64-apple-darwin is in the process of being demoted to Tier 2 with host tools

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

Libraries

• Specify the base path for file!
• Allow storing format_args!() in a variable
• Add #[must_use] to [T; N]::map
• Implement DerefMut for Lazy{Cell,Lock}
• Implement Default for array::IntoIter
• Implement Clone for slice::ChunkBy
• Implement io::Seek for io::Take

Stabilized APIs

• NonZero<char>
• Many intrinsics for x86, not enumerated here
  • AVX512 intrinsics
  • SHA512, SM3 and SM4 intrinsics
• File::lock
• File::lock_shared
• File::try_lock
• File::try_lock_shared
• File::unlock
• NonNull::from_ref
• NonNull::from_mut
• NonNull::without_provenance
• NonNull::with_exposed_provenance
• NonNull::expose_provenance
• OsString::leak
• PathBuf::leak
• Result::flatten
• std::os::linux::net::TcpStreamExt::quickack
• std::os::linux::net::TcpStreamExt::set_quickack

These previously stable APIs are now stable in const contexts:

• <[T; N]>::as_mut_slice
• <[u8]>::eq_ignore_ascii_case
• str::eq_ignore_ascii_case

Cargo

• cargo fix and cargo clippy --fix now default to the same Cargo target selection as other build commands. Previously it would apply to all targets (like binaries, examples, tests, etc.). The --edition flag still applies to all targets.
• Stabilize doctest-xcompile. Doctests are now tested when cross-compiling. Just like other tests, it will use the runner setting to run the tests. If you need to disable tests for a target, you can use the ignore doctest attribute to specify the targets to ignore.

Rustdoc

• On mobile, make the sidebar full width and linewrap. This makes long section and item names much easier to deal with on mobile.

Compatibility Notes

• Make missing_fragment_specifier an unconditional error
• Enabling the neon target feature on aarch64-unknown-none-softfloat causes a warning because mixing code with and without that target feature is not properly supported by LLVM
• Sized Hierarchy: Part I
  • Introduces a small breaking change affecting ?Sized bounds on impls on recursive types which contain associated type projections. It is not expected to affect any existing published crates. Can be fixed by refactoring the involved types or opting into the sized_hierarchy unstable feature. See the FCP report for a code example.
• The warn-by-default elided_named_lifetimes lint is superseded by the warn-by-default mismatched_lifetime_syntaxes lint.
• Error on recursive opaque types earlier in the type checker
• Type inference side effects from requiring element types of array repeat expressions are Copy are now only available at the end of type checking
• The deprecated accidentally-stable std::intrinsics::{copy,copy_nonoverlapping,write_bytes} are now proper intrinsics. There are no debug assertions guarding against UB, and they cannot be coerced to function pointers.
• Remove long-deprecated std::intrinsics::drop_in_place
• Make well-formedness predicates no longer coinductive
• Remove hack when checking impl method compatibility
• Remove unnecessary type inference due to built-in trait object impls
• Lint against "stdcall", "fastcall", and "cdecl" on non-x86-32 targets
• Future incompatibility warnings relating to the never type (!) are now reported in dependencies
• Ensure std::ptr::copy_* intrinsics also perform the static self-init checks
• extern "C" functions on the wasm32-unknown-unknown target now have a standards compliant ABI

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.

• Correctly un-remap compiler sources paths with the rustc-dev component

Rust 1.88.0

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.

Rust 1.87.0

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 (rust-lang/stdarch#1714, rust-lang/stdarch#1716, rust-lang/stdarch#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](https://doc.r...