Sized Hierarchy: Part I by davidtwco · Pull Request #137944 · rust-lang/rust (original) (raw)

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Mar 3, 2025

rustbot added the T-bootstrap

Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap)

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Mar 3, 2025

bjorn3 pushed a commit to rust-lang/rustc_codegen_cranelift that referenced this pull request

Jun 19, 2025

Sized Hierarchy: Part I

This patch implements the non-const parts of rust-lang/rfcs#3729. It introduces two new traits to the standard library, MetaSized and PointeeSized. See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.

These traits are unstable (as is their constness), so users cannot refer to them without opting-in to feature(sized_hierarchy). These traits are not behind cfgs as this would make implementation unfeasible, there would simply be too many cfgs required to add the necessary bounds everywhere. So, like Sized, these traits are automatically implemented by the compiler.

RFC 3729 describes changes which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:

• ?Sized is rewritten as MetaSized
• MetaSized is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.

There are no edition migrations implemented in this, as these are primarily required for the constness parts of the RFC and prior to stabilisation of this (and so will come in follow-up PRs alongside the const parts). All diagnostic output should remain the same (showing ?Sized even if the compiler sees MetaSized) unless the sized_hierarchy feature is enabled.

Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax Deref::Target (this will be investigated separately).

It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Some details might leak through due to the standard library relaxations, but this has not been observed in test output.

Notes:

• Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
• This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
  • Each commit has a short description describing its purpose.
  • This patch is large but it's primarily in the test suite.
• I've worked on the performance of this patch and a few optimisations are implemented so that the performance impact is neutral-to-minor.
• PointeeSized is a different name from the RFC just to make it more obvious that it is different from std::ptr::Pointee but all the names are yet to be bikeshed anyway.
• @nikomatsakis has confirmed that this can proceed as an experiment from the t-lang side
• FCP in rust-lang/rust#137944 (comment)

Fixes rust-lang/rust#79409.

r? @ghost (I'll discuss this with relevant teams to find a reviewer)

github-merge-queue bot pushed a commit to model-checking/kani that referenced this pull request

Jun 24, 2025

Relevant upstream PR: rust-lang/rust#137944 (Sized Hierarchy: Part I). This PR implements a part of RFC 3729, which prescribes a hierarchy of Sized traits. Notably, this disallows instantiation of size_of_val and align_of_val with extern types. Consequently, the code in tests unsized_foreign.rs as well as parts of foreign_type.rs no longer compile (when previously some of the tests would panic). These test were therefore removed.

Resolves: #4165

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

github-actions bot pushed a commit to tautschnig/verify-rust-std that referenced this pull request

Jun 24, 2025

Sized Hierarchy: Part I

This patch implements the non-const parts of rust-lang/rfcs#3729. It introduces two new traits to the standard library, MetaSized and PointeeSized. See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.

These traits are unstable (as is their constness), so users cannot refer to them without opting-in to feature(sized_hierarchy). These traits are not behind cfgs as this would make implementation unfeasible, there would simply be too many cfgs required to add the necessary bounds everywhere. So, like Sized, these traits are automatically implemented by the compiler.

RFC 3729 describes changes which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:

• ?Sized is rewritten as MetaSized
• MetaSized is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.

There are no edition migrations implemented in this, as these are primarily required for the constness parts of the RFC and prior to stabilisation of this (and so will come in follow-up PRs alongside the const parts). All diagnostic output should remain the same (showing ?Sized even if the compiler sees MetaSized) unless the sized_hierarchy feature is enabled.

Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax Deref::Target (this will be investigated separately).

It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Some details might leak through due to the standard library relaxations, but this has not been observed in test output.

Notes:

• Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
• This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
  • Each commit has a short description describing its purpose.
  • This patch is large but it's primarily in the test suite.
• I've worked on the performance of this patch and a few optimisations are implemented so that the performance impact is neutral-to-minor.
• PointeeSized is a different name from the RFC just to make it more obvious that it is different from std::ptr::Pointee but all the names are yet to be bikeshed anyway.
• @nikomatsakis has confirmed that this can proceed as an experiment from the t-lang side
• FCP in rust-lang#137944 (comment)

Fixes rust-lang#79409.

r? @ghost (I'll discuss this with relevant teams to find a reviewer)

GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this pull request

Jun 27, 2025

…r=lcnr

add #![rustc_no_implicit_bounds]

Follow-up from rust-lang#137944.

Adds a new rustc_attrs attribute that stops rustc from adding any default bounds. Useful for tests where default bounds just add noise and make debugging harder.

After reviewing all tests with ?Sized, these tests seem like they could probably benefit from #![rustc_no_implicit_bounds].

• Skipping most of tests/ui/unsized as these seem to want to test ?Sized
• Skipping tests that used Box<T> because it's still bound by T: MetaSized
• Skipping parsing or other tests that cared about ?Sized syntactically
• Skipping tests for derive(CoercePointee) because this appears to check that the pointee type is relaxed with ?Sized explicitly

r? @lcnr

rust-timer added a commit that referenced this pull request

Jun 27, 2025

Rollup merge of #142671 - davidtwco:no-default-bounds-attr, r=lcnr

add #![rustc_no_implicit_bounds]

Follow-up from #137944.

Adds a new rustc_attrs attribute that stops rustc from adding any default bounds. Useful for tests where default bounds just add noise and make debugging harder.

After reviewing all tests with ?Sized, these tests seem like they could probably benefit from #![rustc_no_implicit_bounds].

• Skipping most of tests/ui/unsized as these seem to want to test ?Sized
• Skipping tests that used Box<T> because it's still bound by T: MetaSized
• Skipping parsing or other tests that cared about ?Sized syntactically
• Skipping tests for derive(CoercePointee) because this appears to check that the pointee type is relaxed with ?Sized explicitly

r? @lcnr

github-actions bot pushed a commit to rust-lang/miri that referenced this pull request

Jun 28, 2025

add #![rustc_no_implicit_bounds]

Follow-up from rust-lang/rust#137944.

Adds a new rustc_attrs attribute that stops rustc from adding any default bounds. Useful for tests where default bounds just add noise and make debugging harder.

After reviewing all tests with ?Sized, these tests seem like they could probably benefit from #![rustc_no_implicit_bounds].

• Skipping most of tests/ui/unsized as these seem to want to test ?Sized
• Skipping tests that used Box<T> because it's still bound by T: MetaSized
• Skipping parsing or other tests that cared about ?Sized syntactically
• Skipping tests for derive(CoercePointee) because this appears to check that the pointee type is relaxed with ?Sized explicitly

r? @lcnr

antoyo pushed a commit to rust-lang/rustc_codegen_gcc that referenced this pull request

Jun 28, 2025

Sized Hierarchy: Part I

This patch implements the non-const parts of rust-lang/rfcs#3729. It introduces two new traits to the standard library, MetaSized and PointeeSized. See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.

These traits are unstable (as is their constness), so users cannot refer to them without opting-in to feature(sized_hierarchy). These traits are not behind cfgs as this would make implementation unfeasible, there would simply be too many cfgs required to add the necessary bounds everywhere. So, like Sized, these traits are automatically implemented by the compiler.

RFC 3729 describes changes which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:

• ?Sized is rewritten as MetaSized
• MetaSized is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.

There are no edition migrations implemented in this, as these are primarily required for the constness parts of the RFC and prior to stabilisation of this (and so will come in follow-up PRs alongside the const parts). All diagnostic output should remain the same (showing ?Sized even if the compiler sees MetaSized) unless the sized_hierarchy feature is enabled.

Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax Deref::Target (this will be investigated separately).

It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Some details might leak through due to the standard library relaxations, but this has not been observed in test output.

Notes:

• Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
• This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
  • Each commit has a short description describing its purpose.
  • This patch is large but it's primarily in the test suite.
• I've worked on the performance of this patch and a few optimisations are implemented so that the performance impact is neutral-to-minor.
• PointeeSized is a different name from the RFC just to make it more obvious that it is different from std::ptr::Pointee but all the names are yet to be bikeshed anyway.
• @nikomatsakis has confirmed that this can proceed as an experiment from the t-lang side
• FCP in rust-lang/rust#137944 (comment)

Fixes rust-lang/rust#79409.

r? @ghost (I'll discuss this with relevant teams to find a reviewer)

lcnr mentioned this pull request

Jul 22, 2025

wip-sync pushed a commit to NetBSD/pkgsrc-wip that referenced this pull request

Aug 11, 2025

Pkgsrc changes:

• Adjust patches to adapt to upstream changes and new versions.
• assosicated checksums

Upstream changes relative to 1.88.0:

Version 1.89.0 (2025-08-07)

Language

• [Stabilize explicitly inferred const arguments (feature(generic_arg_infer))] (rust-lang/rust#141610)
• [Add a warn-by-default mismatched_lifetime_syntaxes lint.] (rust-lang/rust#138677) 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] (rust-lang/rust#134536)
• [Make the dangerous_implicit_autorefs lint deny-by-default] (rust-lang/rust#141661)
• [Stabilize the avx512 target features] (rust-lang/rust#138940)
• [Stabilize kl and widekl target features for x86] (rust-lang/rust#140766)
• [Stabilize sha512, sm3 and sm4 target features for x86] (rust-lang/rust#140767)
• [Stabilize LoongArch target features f, d, frecipe, lasx, lbt, lsx, and lvz] (rust-lang/rust#135015)
• [Remove i128 and u128 from improper_ctypes_definitions] (rust-lang/rust#137306)
• [Stabilize repr128 (#[repr(u128)], #[repr(i128)])] (rust-lang/rust#138285)
• [Allow #![doc(test(attr(..)))] everywhere] (rust-lang/rust#140560)
• [Extend temporary lifetime extension to also go through tuple struct and tuple variant constructors] (rust-lang/rust#140593)

Compiler

• [Default to non-leaf frame pointers on aarch64-linux] (rust-lang/rust#140832)
• [Enable non-leaf frame pointers for Arm64EC Windows] (rust-lang/rust#140862)
• [Set Apple frame pointers by architecture] (rust-lang/rust#141797)

Platform Support

• [Add new Tier-3 targets loongarch32-unknown-none and loongarch32-unknown-none-softfloat] (rust-lang/rust#142053)

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

Libraries

• [Specify the base path for file!] (rust-lang/rust#134442)
• [Allow storing format_args!() in a variable] (rust-lang/rust#140748)
• [Add #[must_use] to [T; N]::map] (rust-lang/rust#140957)
• [Implement DerefMut for Lazy{Cell,Lock}] (rust-lang/rust#129334)
• [Implement Default for array::IntoIter] (rust-lang/rust#141574)
• [Implement Clone for slice::ChunkBy] (rust-lang/rust#138016)
• [Implement io::Seek for io::Take] (rust-lang/rust#138023)

Stabilized APIs

• [NonZero<char>] (https://doc.rust-lang.org/stable/std/num/struct.NonZero.html)
• Many intrinsics for x86, not enumerated here
  • AVX512 intrinsics
  • [SHA512, SM3 and SM4 intrinsics] (rust-lang/rust#126624)
• [File::lock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock)
• [File::lock_shared] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock_shared)
• [File::try_lock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock)
• [File::try_lock_shared] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock_shared)
• [File::unlock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.unlock)
• [NonNull::from_ref] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_ref)
• [NonNull::from_mut] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_mut)
• [NonNull::without_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.without_provenance)
• [NonNull::with_exposed_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.with_exposed_provenance)
• [NonNull::expose_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.expose_provenance)
• [OsString::leak] (https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.leak)
• [PathBuf::leak] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.leak)
• [Result::flatten] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.flatten)
• [std::os::linux:🥅:TcpStreamExt::quickack] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.quickack)
• [std::os::linux:🥅:TcpStreamExt::set_quickack] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.set_quickack)

These previously stable APIs are now stable in const contexts:

• [<[T; N]>::as_mut_slice] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.as_mut_slice)
• [<[u8]>::eq_ignore_ascii_case] (https://doc.rust-lang.org/stable/std/primitive.slice.html#impl-%5Bu8%5D/method.eq_ignore_ascii_case)
• [str::eq_ignore_ascii_case] (https://doc.rust-lang.org/stable/std/primitive.str.html#impl-str/method.eq_ignore_ascii_case)

Cargo

• [cargo fix and cargo clippy --fix now default to the same Cargo target selection as other build commands.] (rust-lang/cargo#15192) Previously it would apply to all targets (like binaries, examples, tests, etc.). The --edition flag still applies to all targets.

• [Stabilize doctest-xcompile.] (rust-lang/cargo#15462) Doctests are now tested when cross-compiling. Just like other tests, it will use the [runner setting] (https://doc.rust-lang.org/cargo/reference/config.html#targettriplerunner) to run the tests. If you need to disable tests for a target, you can use the [ignore doctest attribute] (https://doc.rust-lang.org/rustdoc/write-documentation/documentation-tests.html#ignoring-targets) to specify the targets to ignore.

Rustdoc

• [On mobile, make the sidebar full width and linewrap] (rust-lang/rust#139831). This makes long section and item names much easier to deal with on mobile.

Compatibility Notes

• [Make missing_fragment_specifier an unconditional error] (rust-lang/rust#128425)

• [Enabling the neon target feature on aarch64-unknown-none-softfloat causes a warning] (rust-lang/rust#135160) 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] (rust-lang/rust#137944 (comment)) for a code example.

• The warn-by-default elided_named_lifetimes lint is [superseded by the warn-by-default mismatched_lifetime_syntaxes lint.] (rust-lang/rust#138677)

• [Error on recursive opaque types earlier in the type checker] (rust-lang/rust#139419)

• [Type inference side effects from requiring element types of array repeat expressions are Copy are now only available at the end of type checking] (rust-lang/rust#139635)

• [The deprecated accidentally-stable std::intrinsics::{copy,copy_nonoverlapping,write_bytes} are now proper intrinsics] (rust-lang/rust#139916). There are no debug assertions guarding against UB, and they cannot be coerced to function pointers.

• [Remove long-deprecated std::intrinsics::drop_in_place] (rust-lang/rust#140151)

• [Make well-formedness predicates no longer coinductive] (rust-lang/rust#140208)

• [Remove hack when checking impl method compatibility] (rust-lang/rust#140557)

• [Remove unnecessary type inference due to built-in trait object impls] (rust-lang/rust#141352)

• [Lint against "stdcall", "fastcall", and "cdecl" on non-x86-32 targets] (rust-lang/rust#141435)

• [Future incompatibility warnings relating to the never type (!) are now reported in dependencies] (rust-lang/rust#141937)

• [Ensure std::ptr::copy_* intrinsics also perform the static self-init checks] (rust-lang/rust#142575)

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-lang/rust#142377)

tmeijn pushed a commit to tmeijn/dotfiles that referenced this pull request

Aug 12, 2025

This MR contains the following updates:

MR created with the help of el-capitano/tools/renovate-bot.

Proposed changes to behavior should be submitted there as MRs.

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netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request

Oct 18, 2025

Pkgsrc changes:

• Disable the build of NetBSD-*aarch64eb, since it now fails both to cross-build and to build natively. Ref. rust-lang/rust#146842
• Adjusted patches, checksum updates etc.

Upstream changes:

Version 1.90 (2025-09-18)

Language

• [Split up the unknown_or_malformed_diagnostic_attributes lint] (rust-lang/rust#140717). 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] (rust-lang/rust#140942)
• [Allow volatile access to non-Rust memory, including address 0] (rust-lang/rust#141260)

Compiler

• [Use lld by default on x86_64-unknown-linux-gnu] (rust-lang/rust#140525).
• [Tier 3 musl targets now link dynamically by default] (rust-lang/rust#144410). 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] (rust-lang/rust#145252)

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] (rust-lang/rust#126043)
• [Allow comparisons between CStr, CString, and Cow<CStr>] (rust-lang/rust#137268)
• [Remove some unsized tuple impls since unsized tuples can't be constructed] (rust-lang/rust#138340)
• [Set MSG_NOSIGNAL for UnixStream] (rust-lang/rust#140005)
• [proc_macro::Ident::new now supports $crate.] (rust-lang/rust#141996)
• [Guarantee the pointer returned from Thread::into_raw has at least 8 bytes of alignment] (rust-lang/rust#143859)

Stabilized APIs

• [u{n}::checked_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.checked_sub_signed)
• [u{n}::overflowing_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.overflowing_sub_signed)
• [u{n}::saturating_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.saturating_sub_signed)
• [u{n}::wrapping_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.wrapping_sub_signed)
• [impl Copy for IntErrorKind] (https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Copy-for-IntErrorKind)
• [impl Hash for IntErrorKind] (https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Hash-for-IntErrorKind)
• [impl PartialEq<&CStr> for CStr] (https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3C%26CStr%3E-for-CStr)
• [impl PartialEq<CString> for CStr] (https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCString%3E-for-CStr)
• [impl PartialEq<Cow<CStr>> for CStr] (https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CStr)
• [impl PartialEq<&CStr> for CString] (https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3C%26CStr%3E-for-CString)
• [impl PartialEq<CStr> for CString] (https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCStr%3E-for-CString)
• [impl PartialEq<Cow<CStr>> for CString] (https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CString)
• [impl PartialEq<&CStr> for Cow<CStr>] (https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3C%26CStr%3E-for-Cow%3C'_,+CStr%3E)
• [impl PartialEq<CStr> for Cow<CStr>] (https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCStr%3E-for-Cow%3C'_,+CStr%3E)
• [impl PartialEq<CString> for Cow<CStr>] (https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCString%3E-for-Cow%3C'_,+CStr%3E)

These previously stable APIs are now stable in const contexts:

• [<[T]>::reverse] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.reverse)
• [f32::floor] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.floor)
• [f32::ceil] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.ceil)
• [f32::trunc] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.trunc)
• [f32::fract] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.fract) (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.fract)
• [f32::round] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round)
• [f32::round_ties_even] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even)
• [f64::floor] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.floor)
• [f64::ceil] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.ceil)
• [f64::trunc] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.trunc)
• [f64::fract] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.fract)
• [f64::round] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round)
• [f64::round_ties_even] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even)

Cargo

• [Add http.proxy-cainfo config for proxy certs] (rust-lang/cargo#15374)
• [Use gix for cargo package] (rust-lang/cargo#15534)
• [feat(publish): Stabilize multi-package publishing] (rust-lang/cargo#15636)

Rustdoc

• [Add ways to collapse all impl blocks] (rust-lang/rust#141663). 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] (rust-lang/rust#143662)

Compatibility Notes

• [Use lld by default on x86_64-unknown-linux-gnu] (rust-lang/rust#140525). 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] (rust-lang/rust#140985)
• [Set MSG_NOSIGNAL for UnixStream] (rust-lang/rust#140005) 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] (rust-lang/rust#141840)
• We now [reject unsupported extern "{abi}"s consistently in all positions] (rust-lang/rust#142134). 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] (rust-lang/rust#143084)
• [Check that the proc_macro_derive macro has correct arguments when applied to the crate root] (rust-lang/rust#143607)

Version 1.89.0 (2025-08-07)

Language

• [Stabilize explicitly inferred const arguments (feature(generic_arg_infer))] (rust-lang/rust#141610)
• [Add a warn-by-default mismatched_lifetime_syntaxes lint.] (rust-lang/rust#138677) 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] (rust-lang/rust#134536)
• [Make the dangerous_implicit_autorefs lint deny-by-default] (rust-lang/rust#141661)
• [Stabilize the avx512 target features] (rust-lang/rust#138940)
• [Stabilize kl and widekl target features for x86] (rust-lang/rust#140766)
• [Stabilize sha512, sm3 and sm4 target features for x86] (rust-lang/rust#140767)
• [Stabilize LoongArch target features f, d, frecipe, lasx, lbt, lsx, and lvz] (rust-lang/rust#135015)
• [Remove i128 and u128 from improper_ctypes_definitions] (rust-lang/rust#137306)
• [Stabilize repr128 (#[repr(u128)], #[repr(i128)])] (rust-lang/rust#138285)
• [Allow #![doc(test(attr(..)))] everywhere] (rust-lang/rust#140560)
• [Extend temporary lifetime extension to also go through tuple struct and tuple variant constructors] (rust-lang/rust#140593)

Compiler

• [Default to non-leaf frame pointers on aarch64-linux] (rust-lang/rust#140832)
• [Enable non-leaf frame pointers for Arm64EC Windows] (rust-lang/rust#140862)
• [Set Apple frame pointers by architecture] (rust-lang/rust#141797)

Platform Support

• [Add new Tier-3 targets loongarch32-unknown-none and loongarch32-unknown-none-softfloat] (rust-lang/rust#142053)

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

Libraries

• [Specify the base path for file!] (rust-lang/rust#134442)
• [Allow storing format_args!() in a variable] (rust-lang/rust#140748)
• [Add #[must_use] to [T; N]::map] (rust-lang/rust#140957)
• [Implement DerefMut for Lazy{Cell,Lock}] (rust-lang/rust#129334)
• [Implement Default for array::IntoIter] (rust-lang/rust#141574)
• [Implement Clone for slice::ChunkBy] (rust-lang/rust#138016)
• [Implement io::Seek for io::Take] (rust-lang/rust#138023)

Stabilized APIs

• [NonZero<char>] (https://doc.rust-lang.org/stable/std/num/struct.NonZero.html)
• Many intrinsics for x86, not enumerated here
  • AVX512 intrinsics
  • [SHA512, SM3 and SM4 intrinsics] (rust-lang/rust#126624)
• [File::lock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock)
• [File::lock_shared] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock_shared)
• [File::try_lock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock)
• [File::try_lock_shared] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock_shared)
• [File::unlock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.unlock)
• [NonNull::from_ref] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_ref)
• [NonNull::from_mut] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_mut)
• [NonNull::without_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.without_provenance)
• [NonNull::with_exposed_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.with_exposed_provenance)
• [NonNull::expose_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.expose_provenance)
• [OsString::leak] (https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.leak)
• [PathBuf::leak] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.leak)
• [Result::flatten] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.flatten)
• [std::os::linux:🥅:TcpStreamExt::quickack] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.quickack)
• [std::os::linux:🥅:TcpStreamExt::set_quickack] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.set_quickack)

These previously stable APIs are now stable in const contexts:

• [<[T; N]>::as_mut_slice] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.as_mut_slice)
• [<[u8]>::eq_ignore_ascii_case] (https://doc.rust-lang.org/stable/std/primitive.slice.html#impl-%5Bu8%5D/method.eq_ignore_ascii_case)
• [str::eq_ignore_ascii_case] (https://doc.rust-lang.org/stable/std/primitive.str.html#impl-str/method.eq_ignore_ascii_case)

Cargo

• [cargo fix and cargo clippy --fix now default to the same Cargo target selection as other build commands.] (rust-lang/cargo#15192) Previously it would apply to all targets (like binaries, examples, tests, etc.). The --edition flag still applies to all targets.

• [Stabilize doctest-xcompile.] (rust-lang/cargo#15462) Doctests are now tested when cross-compiling. Just like other tests, it will use the [runner setting] (https://doc.rust-lang.org/cargo/reference/config.html#targettriplerunner) to run the tests. If you need to disable tests for a target, you can use the [ignore doctest attribute] (https://doc.rust-lang.org/rustdoc/write-documentation/documentation-tests.html#ignoring-targets) to specify the targets to ignore.

Rustdoc

• [On mobile, make the sidebar full width and linewrap] (rust-lang/rust#139831). This makes long section and item names much easier to deal with on mobile.

Compatibility Notes

• [Make missing_fragment_specifier an unconditional error] (rust-lang/rust#128425)

• [Enabling the neon target feature on aarch64-unknown-none-softfloat causes a warning] (rust-lang/rust#135160) 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] (rust-lang/rust#137944 (comment)) for a code example.

• The warn-by-default elided_named_lifetimes lint is [superseded by the warn-by-default mismatched_lifetime_syntaxes lint.] (rust-lang/rust#138677)

• [Error on recursive opaque types earlier in the type checker] (rust-lang/rust#139419)

• [Type inference side effects from requiring element types of array repeat expressions are Copy are now only available at the end of type checking] (rust-lang/rust#139635)

• [The deprecated accidentally-stable std::intrinsics::{copy,copy_nonoverlapping,write_bytes} are now proper intrinsics] (rust-lang/rust#139916). There are no debug assertions guarding against UB, and they cannot be coerced to function pointers.

• [Remove long-deprecated std::intrinsics::drop_in_place] (rust-lang/rust#140151)

• [Make well-formedness predicates no longer coinductive] (rust-lang/rust#140208)

• [Remove hack when checking impl method compatibility] (rust-lang/rust#140557)

• [Remove unnecessary type inference due to built-in trait object impls] (rust-lang/rust#141352)

• [Lint against "stdcall", "fastcall", and "cdecl" on non-x86-32 targets] (rust-lang/rust#141435)

• [Future incompatibility warnings relating to the never type (!) are now reported in dependencies] (rust-lang/rust#141937)

• [Ensure std::ptr::copy_* intrinsics also perform the static self-init checks] (rust-lang/rust#142575)

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-lang/rust#142377)

netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request

Oct 23, 2025

Pkgsrc changes:

• Disable the build of NetBSD-*aarch64eb, since it now fails both to cross-build and to build natively. Ref. rust-lang/rust#146842
• Adjusted patches, checksum updates etc.

Upstream changes:

Version 1.90 (2025-09-18)

Language

• [Split up the unknown_or_malformed_diagnostic_attributes lint] (rust-lang/rust#140717). 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] (rust-lang/rust#140942)
• [Allow volatile access to non-Rust memory, including address 0] (rust-lang/rust#141260)

Compiler

• [Use lld by default on x86_64-unknown-linux-gnu] (rust-lang/rust#140525).
• [Tier 3 musl targets now link dynamically by default] (rust-lang/rust#144410). 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] (rust-lang/rust#145252)

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] (rust-lang/rust#126043)
• [Allow comparisons between CStr, CString, and Cow<CStr>] (rust-lang/rust#137268)
• [Remove some unsized tuple impls since unsized tuples can't be constructed] (rust-lang/rust#138340)
• [Set MSG_NOSIGNAL for UnixStream] (rust-lang/rust#140005)
• [proc_macro::Ident::new now supports $crate.] (rust-lang/rust#141996)
• [Guarantee the pointer returned from Thread::into_raw has at least 8 bytes of alignment] (rust-lang/rust#143859)

Stabilized APIs

• [u{n}::checked_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.checked_sub_signed)
• [u{n}::overflowing_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.overflowing_sub_signed)
• [u{n}::saturating_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.saturating_sub_signed)
• [u{n}::wrapping_sub_signed] (https://doc.rust-lang.org/stable/std/primitive.usize.html#method.wrapping_sub_signed)
• [impl Copy for IntErrorKind] (https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Copy-for-IntErrorKind)
• [impl Hash for IntErrorKind] (https://doc.rust-lang.org/stable/std/num/enum.IntErrorKind.html#impl-Hash-for-IntErrorKind)
• [impl PartialEq<&CStr> for CStr] (https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3C%26CStr%3E-for-CStr)
• [impl PartialEq<CString> for CStr] (https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCString%3E-for-CStr)
• [impl PartialEq<Cow<CStr>> for CStr] (https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CStr)
• [impl PartialEq<&CStr> for CString] (https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3C%26CStr%3E-for-CString)
• [impl PartialEq<CStr> for CString] (https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCStr%3E-for-CString)
• [impl PartialEq<Cow<CStr>> for CString] (https://doc.rust-lang.org/stable/std/ffi/struct.CString.html#impl-PartialEq%3CCow%3C'_,+CStr%3E%3E-for-CString)
• [impl PartialEq<&CStr> for Cow<CStr>] (https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3C%26CStr%3E-for-Cow%3C'_,+CStr%3E)
• [impl PartialEq<CStr> for Cow<CStr>] (https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCStr%3E-for-Cow%3C'_,+CStr%3E)
• [impl PartialEq<CString> for Cow<CStr>] (https://doc.rust-lang.org/stable/std/borrow/enum.Cow.html#impl-PartialEq%3CCString%3E-for-Cow%3C'_,+CStr%3E)

These previously stable APIs are now stable in const contexts:

• [<[T]>::reverse] (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.reverse)
• [f32::floor] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.floor)
• [f32::ceil] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.ceil)
• [f32::trunc] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.trunc)
• [f32::fract] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.fract) (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.fract)
• [f32::round] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round)
• [f32::round_ties_even] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.round_ties_even)
• [f64::floor] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.floor)
• [f64::ceil] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.ceil)
• [f64::trunc] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.trunc)
• [f64::fract] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.fract)
• [f64::round] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round)
• [f64::round_ties_even] (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.round_ties_even)

Cargo

• [Add http.proxy-cainfo config for proxy certs] (rust-lang/cargo#15374)
• [Use gix for cargo package] (rust-lang/cargo#15534)
• [feat(publish): Stabilize multi-package publishing] (rust-lang/cargo#15636)

Rustdoc

• [Add ways to collapse all impl blocks] (rust-lang/rust#141663). 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] (rust-lang/rust#143662)

Compatibility Notes

• [Use lld by default on x86_64-unknown-linux-gnu] (rust-lang/rust#140525). 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] (rust-lang/rust#140985)
• [Set MSG_NOSIGNAL for UnixStream] (rust-lang/rust#140005) 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] (rust-lang/rust#141840)
• We now [reject unsupported extern "{abi}"s consistently in all positions] (rust-lang/rust#142134). 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] (rust-lang/rust#143084)
• [Check that the proc_macro_derive macro has correct arguments when applied to the crate root] (rust-lang/rust#143607)

Version 1.89.0 (2025-08-07)

Language

• [Stabilize explicitly inferred const arguments (feature(generic_arg_infer))] (rust-lang/rust#141610)
• [Add a warn-by-default mismatched_lifetime_syntaxes lint.] (rust-lang/rust#138677) 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] (rust-lang/rust#134536)
• [Make the dangerous_implicit_autorefs lint deny-by-default] (rust-lang/rust#141661)
• [Stabilize the avx512 target features] (rust-lang/rust#138940)
• [Stabilize kl and widekl target features for x86] (rust-lang/rust#140766)
• [Stabilize sha512, sm3 and sm4 target features for x86] (rust-lang/rust#140767)
• [Stabilize LoongArch target features f, d, frecipe, lasx, lbt, lsx, and lvz] (rust-lang/rust#135015)
• [Remove i128 and u128 from improper_ctypes_definitions] (rust-lang/rust#137306)
• [Stabilize repr128 (#[repr(u128)], #[repr(i128)])] (rust-lang/rust#138285)
• [Allow #![doc(test(attr(..)))] everywhere] (rust-lang/rust#140560)
• [Extend temporary lifetime extension to also go through tuple struct and tuple variant constructors] (rust-lang/rust#140593)

Compiler

• [Default to non-leaf frame pointers on aarch64-linux] (rust-lang/rust#140832)
• [Enable non-leaf frame pointers for Arm64EC Windows] (rust-lang/rust#140862)
• [Set Apple frame pointers by architecture] (rust-lang/rust#141797)

Platform Support

• [Add new Tier-3 targets loongarch32-unknown-none and loongarch32-unknown-none-softfloat] (rust-lang/rust#142053)

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

Libraries

• [Specify the base path for file!] (rust-lang/rust#134442)
• [Allow storing format_args!() in a variable] (rust-lang/rust#140748)
• [Add #[must_use] to [T; N]::map] (rust-lang/rust#140957)
• [Implement DerefMut for Lazy{Cell,Lock}] (rust-lang/rust#129334)
• [Implement Default for array::IntoIter] (rust-lang/rust#141574)
• [Implement Clone for slice::ChunkBy] (rust-lang/rust#138016)
• [Implement io::Seek for io::Take] (rust-lang/rust#138023)

Stabilized APIs

• [NonZero<char>] (https://doc.rust-lang.org/stable/std/num/struct.NonZero.html)
• Many intrinsics for x86, not enumerated here
  • AVX512 intrinsics
  • [SHA512, SM3 and SM4 intrinsics] (rust-lang/rust#126624)
• [File::lock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock)
• [File::lock_shared] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock_shared)
• [File::try_lock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock)
• [File::try_lock_shared] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock_shared)
• [File::unlock] (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.unlock)
• [NonNull::from_ref] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_ref)
• [NonNull::from_mut] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_mut)
• [NonNull::without_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.without_provenance)
• [NonNull::with_exposed_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.with_exposed_provenance)
• [NonNull::expose_provenance] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.expose_provenance)
• [OsString::leak] (https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.leak)
• [PathBuf::leak] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.leak)
• [Result::flatten] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.flatten)
• [std::os::linux:🥅:TcpStreamExt::quickack] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.quickack)
• [std::os::linux:🥅:TcpStreamExt::set_quickack] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.set_quickack)

These previously stable APIs are now stable in const contexts:

• [<[T; N]>::as_mut_slice] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.as_mut_slice)
• [<[u8]>::eq_ignore_ascii_case] (https://doc.rust-lang.org/stable/std/primitive.slice.html#impl-%5Bu8%5D/method.eq_ignore_ascii_case)
• [str::eq_ignore_ascii_case] (https://doc.rust-lang.org/stable/std/primitive.str.html#impl-str/method.eq_ignore_ascii_case)

Cargo

• [cargo fix and cargo clippy --fix now default to the same Cargo target selection as other build commands.] (rust-lang/cargo#15192) Previously it would apply to all targets (like binaries, examples, tests, etc.). The --edition flag still applies to all targets.

• [Stabilize doctest-xcompile.] (rust-lang/cargo#15462) Doctests are now tested when cross-compiling. Just like other tests, it will use the [runner setting] (https://doc.rust-lang.org/cargo/reference/config.html#targettriplerunner) to run the tests. If you need to disable tests for a target, you can use the [ignore doctest attribute] (https://doc.rust-lang.org/rustdoc/write-documentation/documentation-tests.html#ignoring-targets) to specify the targets to ignore.

Rustdoc

• [On mobile, make the sidebar full width and linewrap] (rust-lang/rust#139831). This makes long section and item names much easier to deal with on mobile.

Compatibility Notes

• [Make missing_fragment_specifier an unconditional error] (rust-lang/rust#128425)

• [Enabling the neon target feature on aarch64-unknown-none-softfloat causes a warning] (rust-lang/rust#135160) 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] (rust-lang/rust#137944 (comment)) for a code example.

• The warn-by-default elided_named_lifetimes lint is [superseded by the warn-by-default mismatched_lifetime_syntaxes lint.] (rust-lang/rust#138677)

• [Error on recursive opaque types earlier in the type checker] (rust-lang/rust#139419)

• [Type inference side effects from requiring element types of array repeat expressions are Copy are now only available at the end of type checking] (rust-lang/rust#139635)

• [The deprecated accidentally-stable std::intrinsics::{copy,copy_nonoverlapping,write_bytes} are now proper intrinsics] (rust-lang/rust#139916). There are no debug assertions guarding against UB, and they cannot be coerced to function pointers.

• [Remove long-deprecated std::intrinsics::drop_in_place] (rust-lang/rust#140151)

• [Make well-formedness predicates no longer coinductive] (rust-lang/rust#140208)

• [Remove hack when checking impl method compatibility] (rust-lang/rust#140557)

• [Remove unnecessary type inference due to built-in trait object impls] (rust-lang/rust#141352)

• [Lint against "stdcall", "fastcall", and "cdecl" on non-x86-32 targets] (rust-lang/rust#141435)

• [Future incompatibility warnings relating to the never type (!) are now reported in dependencies] (rust-lang/rust#141937)

• [Ensure std::ptr::copy_* intrinsics also perform the static self-init checks] (rust-lang/rust#142575)

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-lang/rust#142377)

theemathas added a commit to theemathas/rust that referenced this pull request

Dec 10, 2025

These TrivialClone impls previously had ?Sized bounds, which are different from the PointeeSized bounds on the corresponding Clone and Copy impls. So, I've changed the ?Sized bounds into PointeeSized bounds.

This mistake was made presumably because the TrivialClone PR (rust-lang#135634) was opened in Jan 2025, but merged in Nov 2025. During that time, the sized hierachy PR (rust-lang#137944) was opened in Mar 2025, and merged in Jun 2025. The TrivialClone PR was not updated to account for the sized hierachy changes.

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Dec 10, 2025

…ized, r=joboet

Use PointeeSized bound for TrivialClone impls

These TrivialClone impls previously had ?Sized bounds, which are different from the PointeeSized bounds on the corresponding Clone and Copy impls. So, I've changed the ?Sized bounds into PointeeSized bounds.

This mistake was made presumably because the TrivialClone PR (rust-lang#135634) was opened in Jan 2025, but merged in Nov 2025. During that time, the sized hierachy PR (rust-lang#137944) was opened in Mar 2025, and merged in Jun 2025. The TrivialClone PR was not updated to account for the sized hierachy changes.

r? @joboet

rust-timer added a commit that referenced this pull request

Dec 10, 2025

Rollup merge of #149839 - theemathas:trivial-clone-pointee-sized, r=joboet

Use PointeeSized bound for TrivialClone impls

These TrivialClone impls previously had ?Sized bounds, which are different from the PointeeSized bounds on the corresponding Clone and Copy impls. So, I've changed the ?Sized bounds into PointeeSized bounds.

This mistake was made presumably because the TrivialClone PR (#135634) was opened in Jan 2025, but merged in Nov 2025. During that time, the sized hierachy PR (#137944) was opened in Mar 2025, and merged in Jun 2025. The TrivialClone PR was not updated to account for the sized hierachy changes.

r? @joboet