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Draft release notes for 1.100.0聽#163811
Description
NOTE: Use the 馃摑 links to edit those that have a relnotes-tracking-issue,
and they will be updated when we regenerate the notes periodically (manually).
Version 1.100.0 (2026-11-12)
Language
- Stabilize never type
馃摑 - Lint against repeated
#[repr(..)]attributes
馃摑 - Stabilize
extern "custom"
馃摑 - Extend
dropping_references,dropping_copy_typesandundropped_manually_dropslints todrop_in_place
馃摑 unfulfilled_lint_expectationsno longer fires on#[expect(dead_code)]inside code that is covered by a dead parents' diagnostic
馃摑- riscv: stabilize 'd' and 'f' target features
馃摑 - Turn the error for
repr(align)fields in arepr(packed)type into a (deny-by-default) lint,aligned_fields_in_packed.
馃摑
Compiler
Platform Support
i686-pc-windows-gnuis now a tier 2 without host tools target
馃摑- Promote
wasm32-wasip3to Tier 2
馃摑 - Add new Tier 3 target
powerpc64-sony-ps3
馃摑
Refer to Rust's platform support page
for more information on Rust's tiered platform support.
Libraries
- Stabilize custom allocators
馃摑 - Map
ENOTSUPtoErrorKind::Unsupported
馃摑 - volatile: allow accesses to non-AM memory to trap
- Fix soundness issues in std::sys::pal::sgx::waitqueue::unsafe_list
馃摑
Stabilized APIs
impl PartialEq<Cow<'_, [U]>> for Vec<T, A>impl PartialEq<Cow<'_, [U]>> for &[T]impl PartialEq<Cow<'_, [U]>> for &mut [T]
馃摑std::alloc::Allocatorstd::alloc::Globalstd::alloc::Systemimpl Allocator for Globalimpl Allocator for Systemimpl<A: Allocator> for &Aimpl<T: Allocator, A: Allocator> for Box<T, A>impl<A: Allocator> for &mut Aimpl<T: Allocator, A: Allocator> for Arc<T, A>impl<T: Allocator, A: Allocator> for Rc<T, A>Box::new_inBox::from_raw_inBox::from_non_null_inBox::into_raw_with_allocatorBox::into_non_null_with_allocatorBox::allocatorVec::new_inVec::with_capacity_inVec::from_raw_parts_inVec::from_parts_inVec::into_raw_parts_with_allocatorVec::into_parts_with_allocatorVec::allocator
馃摑Child::main_thread_handle
馃摑impl Default for std::sync::Once
馃摑bool::toggle
馃摑Box::take
馃摑Box::mapRc::mapArc::map
馃摑core::mem::DropGuard
馃摑std::mem::conjure_zst
馃摑
These previously stable APIs are now stable in const contexts:
Cargo
- feat(diag): Stabilize cargo-lints
- docs: adopt rust-lang/rust's LLM usage policy
- fix(update)!: Remove unstable
--breaking - feat(resolver): Stabilize min-publish-age
- Re-stabilize build-dir layout v2
- fix(install): use packaged lockfile by default
Rustdoc
Compatibility Notes
- More precise captures for closure with uses of variables in
if lets may cause new errors
馃摑 - Always require trait objects to be dyn-compatible
馃摑 Infallibleis now a type alias to!- The never type fallback was changed to
!on all editions
馃摑 boxpatterns are no longer syntactically allowed
馃摑- Report Query Cycle errors in more cases when computing the layout of enums with explicit discriminants
馃摑 - Always escape grapheme extenders in
str::escape_debug
馃摑 - Make let-else respect
macro_rulesexprmetavariable grouping
馃摑 Iterator::{min,max}(_by_key)changed whichOrdmethods they use. This cannot change behaviour (other than being potentially faster) for types correctly following theOrdrules, but may impact types with inconsistent trait implementations.
馃摑- Emit an error when trying to enable SSE/AVX on an x86 (32bit or 64bit) softfloat target
馃摑 - Require windowed (and exception) for Xtensa ABI
馃摑 - windows-gnullvm: always link libunwind statically
馃摑 - From version 1.94 up to 1.100 a number of ARMv7-A hardfloat targets required the
VFPv3-D32FPU as a minimum, as they erroneously had thed32feature in their baseline list of features. Breakage introduced as a result of correcting this can be fixed by passing-Ctarget-feature=+d32to Rust.
馃摑 - Change "Rust" ABI on x86 to use SSE registers if they are always-available for the current target
馃摑 - Make
ambiguous_glob_imported_traitsfire in slightly more cases
馃摑 - Make
+fix-cortex-a53-835769a default feature foraarch64-unknown-fuchsia
馃摑 - Some impls on
Boxhave been generalised to arbitrary allocators which may cause some new type inference errors
馃摑 - On ARM targets,
-Ctarget-feature/-Ctarget-cpuvalues that would alter the ABI are rejected as hard errors now.
馃摑
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.
Activity
BoxyUwU commentedon Oct 5, 2026
cc @rust-lang/release
@rustbot ping relnotes-interest-group
rustbot commentedon Oct 5, 2026
Hi relnotes-interest-group, this issue/PR could use some help in reviewing /
adjusting release notes. Could you take a look if available? Thanks <3
cc @alex-semenyuk @jieyouxu @joshtriplett @lcnr @traviscross @weihanglo
theemathas commentedon Oct 6, 2026
This belongs under "language", not "library". However... the link to the relnotes issue is missing, so I can't edit that.
theemathas commentedon Oct 6, 2026
I would link to https://doc.rust-lang.org/cargo/reference/lints.html, and also mention that users will now get warnings about unused dependencies, among other things.
I don't think this needs relnotes
This should also have a link to https://blog.rust-lang.org/2026/03/13/call-for-testing-build-dir-layout-v2/
weihanglo commentedon Oct 6, 2026
@theemathas agreed with you on all your points. For cargo we probably only need these things.
And prehaps the build dir layout as a compat note:
See also Cargo's changelog: https://doc.rust-lang.org/nightly/cargo/CHANGELOG.html#cargo-1100-2026-11-12