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document assumptions about Clone and Eq traits
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library/core/src/clone.rs
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| /// Violating this property is a logic error. The behavior resulting from a logic error is not | ||
| /// specified, but users of the trait must ensure that such logic errors do *not* result in | ||
| /// undefined behavior. This means that `unsafe` code **must not** rely on the correctness of these | ||
| /// methods. |
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It's a bit confusing to say "these methods" here IMO - maybe "this property"?
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I agree, I could change it to "... rely on this property being satisfied."
The reason behind the "correctness of these methods" wording is that it is phrased like this in the documentation on Hash and Eq, as well as the Eq and PartialEq trait documentation. I found it confusing there, too, but I thought it was just because I lacked experience with the terminology.
So, would you say the wording in these other places is confusing, too? And if so, should I make it part of this PR to change it there, too? (my first time doing a PR like this, so I'm still learning best practices)
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Moving into libs-api queue for FCP, since this is a new property (even if likely already required implicitly) so merits some team discussion. |
| /// // Note: With the manual implementations the above line will compile. | ||
| /// ``` | ||
| /// | ||
| /// ## `Clone` and `PartialEq`/`Eq` |
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It's unclear whether this should apply to PartialEq.
However this definitely needs to be extended to include Hash and Ord since HashMap and BTreeMap rely on this. It could also have vague wording that this may extend to other traits as well.
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It's unclear whether this should apply to PartialEq.
Do you mean this in the sense that the property cannot be required of PartialEq and Clone as we might have to deliberalty break it in some contexts? Or in the sense that we just don't know of anything that depends on this property for PartialEq?
In case of the latter, I would argue that the documentation of Clone – "creation of a duplicate value" – very strongly suggests that I get the "same" thing by cloning, and PartialEq defines "sameness" of objects. E.g., if f == 1.0_f64, I expect that f.clone() == 1.0_f64, too. But without the property x == x -> x.clone() == x, this is never explicitly guaranteed anywhere.
However this definitely needs to be extended to include Hash and Ord since HashMap and BTreeMap rely on this. It could also have vague wording that this may extend to other traits as well.
I only wrote about PartialEq/Eq because x.clone() == x already ensures that clone preserves the hash and ordering of elements, when put together with the guarantees that are required of Hash (see "Hash and Eq") and Ord (due to the conditions for PartialOrd). But I could make this interaction explicit.
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Now that I think about it, you are correct and PartialEq is the right place to introduce this requirement.
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@bors r+ rollup |
…=Amanieu document assumptions about `Clone` and `Eq` traits Most standard library collections break if `Clone` has a non-standard implementation which violates `x.clone() == x`. [Here](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=b7fc6dfa8410cbb673eb8d38393d81de) the resulting broken behaviour of different collections is shown. I originally created an issue at rust-lang/hashbrown#629, but the conclusion there was that `x.clone()` resulting in an object that compares equal to the original one is probably a very universal assumption. However, this assumption is (to my knowledge) not documented anywhere. I propose to make this assumption explicit in the `Clone` trait documentation. The property that seems the most reasonable to me is the following: When implementing both `Clone` and `PartialEq`, then ```text x == x -> x.clone() == x ``` is expected to hold. This way, when also implementing `Eq`, it automatically follows that `x.clone() == x` has to hold, which should be enough for the collections to not break. At the same time, the property also works for the "normal" elements of a type with `PartialEq`. For the wording, I tried to follow the [`Hash` and `Eq`](https://doc.rust-lang.org/std/hash/trait.Hash.html#hash-and-eq) documentation. As I am fairly new to Rust, it might well be that this property cannot be generally expected – it seems reasonable to me, but any counter-examples or critique, both content- and wording-wise, would be very welcome. If the property turns out to be too general, I would suggest to at least document the assumption of `x.clone() == x` for the collections somehow. An additional thought of mine: If it is indeed generally expected that `x == x -> x.clone() == x`, then, for the sake of completeness, one could also define that `x != x -> y != y for y = x.clone()` should hold, i.e., that an object that did not compare equal to itself before cloning, should also not compare equal to itself afterwards.
Rollup of 7 pull requests Successful merges: - #143949 (Constify remaining traits/impls for `const_ops`) - #144330 (document assumptions about `Clone` and `Eq` traits) - #144350 (std: sys: io: io_slice: Add UEFI types) - #144558 (Point at the `Fn()` or `FnMut()` bound that coerced a closure, which caused a move error) - #145149 (Make config method invoke inside parse use dwn_ctx) - #145227 (Tweak spans providing type context on errors when involving macros) - #145228 (Remove unnecessary parentheses in `assert!`s) r? `@ghost` `@rustbot` modify labels: rollup
Rollup merge of #144330 - gewitternacht:document-clone-eq, r=Amanieu document assumptions about `Clone` and `Eq` traits Most standard library collections break if `Clone` has a non-standard implementation which violates `x.clone() == x`. [Here](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=b7fc6dfa8410cbb673eb8d38393d81de) the resulting broken behaviour of different collections is shown. I originally created an issue at rust-lang/hashbrown#629, but the conclusion there was that `x.clone()` resulting in an object that compares equal to the original one is probably a very universal assumption. However, this assumption is (to my knowledge) not documented anywhere. I propose to make this assumption explicit in the `Clone` trait documentation. The property that seems the most reasonable to me is the following: When implementing both `Clone` and `PartialEq`, then ```text x == x -> x.clone() == x ``` is expected to hold. This way, when also implementing `Eq`, it automatically follows that `x.clone() == x` has to hold, which should be enough for the collections to not break. At the same time, the property also works for the "normal" elements of a type with `PartialEq`. For the wording, I tried to follow the [`Hash` and `Eq`](https://doc.rust-lang.org/std/hash/trait.Hash.html#hash-and-eq) documentation. As I am fairly new to Rust, it might well be that this property cannot be generally expected – it seems reasonable to me, but any counter-examples or critique, both content- and wording-wise, would be very welcome. If the property turns out to be too general, I would suggest to at least document the assumption of `x.clone() == x` for the collections somehow. An additional thought of mine: If it is indeed generally expected that `x == x -> x.clone() == x`, then, for the sake of completeness, one could also define that `x != x -> y != y for y = x.clone()` should hold, i.e., that an object that did not compare equal to itself before cloning, should also not compare equal to itself afterwards.
…=Amanieu document assumptions about `Clone` and `Eq` traits Most standard library collections break if `Clone` has a non-standard implementation which violates `x.clone() == x`. [Here](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=b7fc6dfa8410cbb673eb8d38393d81de) the resulting broken behaviour of different collections is shown. I originally created an issue at rust-lang/hashbrown#629, but the conclusion there was that `x.clone()` resulting in an object that compares equal to the original one is probably a very universal assumption. However, this assumption is (to my knowledge) not documented anywhere. I propose to make this assumption explicit in the `Clone` trait documentation. The property that seems the most reasonable to me is the following: When implementing both `Clone` and `PartialEq`, then ```text x == x -> x.clone() == x ``` is expected to hold. This way, when also implementing `Eq`, it automatically follows that `x.clone() == x` has to hold, which should be enough for the collections to not break. At the same time, the property also works for the "normal" elements of a type with `PartialEq`. For the wording, I tried to follow the [`Hash` and `Eq`](https://doc.rust-lang.org/std/hash/trait.Hash.html#hash-and-eq) documentation. As I am fairly new to Rust, it might well be that this property cannot be generally expected – it seems reasonable to me, but any counter-examples or critique, both content- and wording-wise, would be very welcome. If the property turns out to be too general, I would suggest to at least document the assumption of `x.clone() == x` for the collections somehow. An additional thought of mine: If it is indeed generally expected that `x == x -> x.clone() == x`, then, for the sake of completeness, one could also define that `x != x -> y != y for y = x.clone()` should hold, i.e., that an object that did not compare equal to itself before cloning, should also not compare equal to itself afterwards.
This MR contains the following updates: | Package | Update | Change | |---|---|---| | [rust](https://github.com/rust-lang/rust) | minor | `1.90.0` -> `1.91.0` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>rust-lang/rust (rust)</summary> ### [`v1.91.0`](https://github.com/rust-lang/rust/blob/HEAD/RELEASES.md#Version-1910-2025-10-30) [Compare Source](rust-lang/rust@1.90.0...1.91.0) \========================== <a id="1.91.0-Language"></a> ## Language - [Lower pattern bindings in the order they're written and base drop order on primary bindings' order](rust-lang/rust#143764) - [Stabilize declaration of C-style variadic functions for `sysv64`, `win64`, `efiapi`, and `aapcs` ABIs](rust-lang/rust#144066). 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](rust-lang/rust#144322) - [Upgrade `semicolon_in_expressions_from_macros` from warn to deny](rust-lang/rust#144369) - [Stabilize LoongArch32 inline assembly](rust-lang/rust#144402) - [Add warn-by-default `integer_to_ptr_transmutes` lint against integer-to-pointer transmutes](rust-lang/rust#144531) - [Stabilize `sse4a` and `tbm` target features](rust-lang/rust#144542) - [Add `target_env = "macabi"` and `target_env = "sim"` cfgs](rust-lang/rust#139451) as replacements for the `target_abi` cfgs with the same values. <a id="1.91.0-Compiler"></a> ## Compiler - [Don't warn on never-to-any `as` casts as unreachable](rust-lang/rust#144804) <a id="1.91.0-Platform-Support"></a> ## Platform Support - [Promote `aarch64-pc-windows-gnullvm` and `x86_64-pc-windows-gnullvm` to Tier 2 with host tools.](rust-lang/rust#143031) Note: llvm-tools and MSI installers are missing but will be added in future releases. - [Promote `aarch64-pc-windows-msvc` to Tier 1](rust-lang/rust#145682) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. [platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html <a id="1.91.0-Libraries"></a> ## Libraries - [Print thread ID in panic message](rust-lang/rust#115746) - [Fix overly restrictive lifetime in `core::panic::Location::file` return type](rust-lang/rust#132087) - [Guarantee parameter order for `_by()` variants of `min` / `max`/ `minmax` in `std::cmp`](rust-lang/rust#139357) - [Document assumptions about `Clone` and `Eq` traits](rust-lang/rust#144330) - [`std::thread`: Return error if setting thread stack size fails](rust-lang/rust#144210) This used to panic within the standard library. <a id="1.91.0-Stabilized-APIs"></a> ## Stabilized APIs - [`Path::file_prefix`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.file_prefix) - [`AtomicPtr::fetch_ptr_add`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_ptr_add) - [`AtomicPtr::fetch_ptr_sub`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_ptr_sub) - [`AtomicPtr::fetch_byte_add`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_byte_add) - [`AtomicPtr::fetch_byte_sub`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_byte_sub) - [`AtomicPtr::fetch_or`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_or) - [`AtomicPtr::fetch_and`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_and) - [`AtomicPtr::fetch_xor`](https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_xor) - [`{integer}::strict_add`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_add) - [`{integer}::strict_sub`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_sub) - [`{integer}::strict_mul`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_mul) - [`{integer}::strict_div`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_div) - [`{integer}::strict_div_euclid`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_div_euclid) - [`{integer}::strict_rem`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_rem) - [`{integer}::strict_rem_euclid`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_rem_euclid) - [`{integer}::strict_neg`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_neg) - [`{integer}::strict_shl`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_shl) - [`{integer}::strict_shr`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_shr) - [`{integer}::strict_pow`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_pow) - [`i{N}::strict_add_unsigned`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_add_unsigned) - [`i{N}::strict_sub_unsigned`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_sub_unsigned) - [`i{N}::strict_abs`](https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_abs) - [`u{N}::strict_add_signed`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_add_signed) - [`u{N}::strict_sub_signed`](https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_sub_signed) - [`PanicHookInfo::payload_as_str`](https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html#method.payload_as_str) - [`core::iter::chain`](https://doc.rust-lang.org/stable/core/iter/fn.chain.html) - [`u{N}::checked_signed_diff`](https://doc.rust-lang.org/stable/std/primitive.u16.html#method.checked_signed_diff) - [`core::array::repeat`](https://doc.rust-lang.org/stable/core/array/fn.repeat.html) - [`PathBuf::add_extension`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.add_extension) - [`PathBuf::with_added_extension`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.with_added_extension) - [`Duration::from_mins`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_mins) - [`Duration::from_hours`](https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_hours) - [`impl PartialEq<str> for PathBuf`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-PartialEq%3Cstr%3E-for-PathBuf) - [`impl PartialEq<String> for PathBuf`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-PartialEq%3CString%3E-for-PathBuf) - [`impl PartialEq<str> for Path`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#impl-PartialEq%3Cstr%3E-for-Path) - [`impl PartialEq<String> for Path`](https://doc.rust-lang.org/stable/std/path/struct.Path.html#impl-PartialEq%3CString%3E-for-Path) - [`impl PartialEq<PathBuf> for String`](https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-PartialEq%3CPathBuf%3E-for-String) - [`impl PartialEq<Path> for String`](https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-PartialEq%3CPath%3E-for-String) - [`impl PartialEq<PathBuf> for str`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-PartialEq%3CPathBuf%3E-for-str) - [`impl PartialEq<Path> for str`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-PartialEq%3CPath%3E-for-str) - [`Ipv4Addr::from_octets`](https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.from_octets) - [`Ipv6Addr::from_octets`](https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.from_octets) - [`Ipv6Addr::from_segments`](https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.from_segments) - [`impl<T> Default for Pin<Box<T>> where Box<T>: Default, T: ?Sized`](https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CBox%3CT%3E%3E) - [`impl<T> Default for Pin<Rc<T>> where Rc<T>: Default, T: ?Sized`](https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CRc%3CT%3E%3E) - [`impl<T> Default for Pin<Arc<T>> where Arc<T>: Default, T: ?Sized`](https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CArc%3CT%3E%3E) - [`Cell::as_array_of_cells`](https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.as_array_of_cells) - [`u{N}::carrying_add`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_add) - [`u{N}::borrowing_sub`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.borrowing_sub) - [`u{N}::carrying_mul`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_mul) - [`u{N}::carrying_mul_add`](https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_mul_add) - [`BTreeMap::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.extract_if) - [`BTreeSet::extract_if`](https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.extract_if) - [`impl Debug for windows::ffi::EncodeWide<'_>`](https://doc.rust-lang.org/stable/std/os/windows/ffi/struct.EncodeWide.html#impl-Debug-for-EncodeWide%3C'_%3E) - [`str::ceil_char_boundary`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.ceil_char_boundary) - [`str::floor_char_boundary`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.floor_char_boundary) - [`impl Sum for Saturating<u{N}>`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Sum-for-Saturating%3Cu32%3E) - [`impl Sum<&Self> for Saturating<u{N}>`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Sum%3C%26Saturating%3Cu32%3E%3E-for-Saturating%3Cu32%3E) - [`impl Product for Saturating<u{N}>`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Product-for-Saturating%3Cu32%3E) - [`impl Product<&Self> for Saturating<u{N}>`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Product%3C%26Saturating%3Cu32%3E%3E-for-Saturating%3Cu32%3E) These previously stable APIs are now stable in const contexts: - [`<[T; N]>::each_ref`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_ref) - [`<[T; N]>::each_mut`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_mut) - [`OsString::new`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.new) - [`PathBuf::new`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.new) - [`TypeId::of`](https://doc.rust-lang.org/stable/std/any/struct.TypeId.html#method.of) - [`ptr::with_exposed_provenance`](https://doc.rust-lang.org/stable/std/ptr/fn.with_exposed_provenance.html) - [`ptr::with_exposed_provenance_mut`](https://doc.rust-lang.org/stable/std/ptr/fn.with_exposed_provenance_mut.html) <a id="1.91.0-Cargo"></a> ## Cargo - 🎉 Stabilize `build.build-dir`. This config sets the directory where intermediate build artifacts are stored. These artifacts are produced by Cargo and rustc during the build process. End users usually won't need to interact with them, and the layout inside `build-dir` is an implementation detail that may change without notice. ([config doc](https://doc.rust-lang.org/stable/cargo/reference/config.html#buildbuild-dir)) ([build cache doc](https://doc.rust-lang.org/stable/cargo/reference/build-cache.html)) [#​15833](rust-lang/cargo#15833) [#​15840](rust-lang/cargo#15840) - The `--target` flag and the `build.target` configuration can now take literal `"host-tuple"` string, which will internally be substituted by the host machine's target triple. [#​15838](rust-lang/cargo#15838) [#​16003](rust-lang/cargo#16003) [#​16032](rust-lang/cargo#16032) <a id="1.91.0-Rustdoc"></a> ## Rustdoc - [In search results, rank doc aliases lower than non-alias items with the same name](rust-lang/rust#145100) - [Raw pointers now work in type-based search like references](rust-lang/rust#145731). This means you can now search for things like `*const u8 ->`, and additionally functions that take or return raw pointers will now display their signature properly in search results. <a id="1.91.0-Compatibility-Notes"></a> ## Compatibility Notes - [Always require coroutine captures to be drop-live](rust-lang/rust#144156) - [Apple: Always pass SDK root when linking with `cc`, and pass it via `SDKROOT` env var](rust-lang/rust#131477). This should fix linking issues with `rustc` running inside Xcode. Libraries in `/usr/local/lib` may no longer be linked automatically, if you develop or use a crate that relies on this, you should explicitly set `cargo::rustc-link-search=/usr/local/lib` in a `build.rs` script. - [Relaxed bounds in associated type bound position like in `TraitRef<AssocTy: ?Sized>` are now correctly forbidden](rust-lang/rust#135331) - [Add unstable `#[sanitize(xyz = "on|off")]` built-in attribute that shadows procedural macros with the same name](rust-lang/rust#142681) - [Fix the drop checker being more permissive for bindings declared with let-else](rust-lang/rust#143028) - [Be more strict when parsing attributes, erroring on many invalid attributes](rust-lang/rust#144689) - [Error on invalid `#[should_panic]` attributes](rust-lang/rust#143808) - [Error on invalid `#[link]` attributes](rust-lang/rust#143193) - [Mark all deprecation lints in name resolution as deny-by-default and also report in dependencies](rust-lang/rust#143929) - The lint `semicolon_in_expressions_from_macros`, for `macro_rules!` macros in expression position that expand to end in a semicolon (`;`), is now deny-by-default. It was already warn-by-default, and a future compatibility warning (FCW) that warned even in dependencies. This lint will become a hard error in the future. - [Trait impl modifiers (e.g., `unsafe`, `!`, `default`) in inherent impls are no longer syntactically valid](rust-lang/rust#144386) - [Start reporting future breakage for `ill_formed_attribute_input` in dependencies](rust-lang/rust#144544) - [Restrict the scope of temporaries created by the macros `pin!`, `format_args!`, `write!`, and `writeln!` in `if let` scrutinees in Rust Edition 2024.](rust-lang/rust#145342) This applies [Rust Edition 2024's `if let` temporary scope rules](https://doc.rust-lang.org/edition-guide/rust-2024/temporary-if-let-scope.html) to these temporaries, which previously could live past the `if` expression regardless of Edition. - [Invalid numeric literal suffixes in tuple indexing, tuple struct indexing, and struct field name positions are now correctly rejected](rust-lang/rust#145463) - [Closures marked with the keyword `static` are now syntactically invalid](rust-lang/rust#145604) - [Shebangs inside `--cfg` and `--check-cfg` arguments are no longer allowed](rust-lang/rust#146211) - [Add future incompatibility lint for temporary lifetime shortening in Rust 1.92](rust-lang/rust#147056) Cargo compatibility notes: - `cargo publish` no longer keeps `.crate` tarballs as final build artifacts when `build.build-dir` is set. These tarballs were previously included due to an oversight and are now treated as intermediate artifacts. To get `.crate` tarballs as final artifacts, use `cargo package`. In a future version, this change will apply regardless of `build.build-dir`. [#​15910](rust-lang/cargo#15910) - Adjust Cargo messages to match rustc diagnostic style. This changes some of the terminal colors used by Cargo messages. [#​15928](rust-lang/cargo#15928) - Tools and projects relying on the [internal details of Cargo's `build-dir`](https://doc.rust-lang.org/cargo/reference/build-cache.html) may not work for users changing their `build-dir` layout. For those doing so, we'd recommend proactively testing these cases particularly as we are considering changing the default location of the `build-dir` in the future ([cargo#16147](rust-lang/cargo#16147)). If you can't migrate off of Cargo's internal details, we'd like to learn more about your use case as we prepare to change the layout of the `build-dir` ([cargo#15010](rust-lang/cargo#15010)). <a id="1.91.0-Internal-Changes"></a> ## Internal Changes These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Update to LLVM 21](rust-lang/rust#143684) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] <!-- rebase-check -->If you want to rebase/retry this MR, check this box --- This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate). <!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS4xNjkuMSIsInVwZGF0ZWRJblZlciI6IjQxLjE2OS4xIiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6WyJSZW5vdmF0ZSBCb3QiXX0=-->
Pkgsrc changes: * Adjust patches to adapt to upstream changes and new versions. * assosicated checksums * Add a workaround for LLVM mis-using -isystem. Reported upstream at llvm/llvm-project#166420 Noteable failures at the time of commit: * The cross-build for armv6 fails, reported upstream at rust-lang/rust#148464 * The cross-build for powerpc fails, reported upstream at rust-lang/rust#148497 This is R_PPC_PLTREL24 which now has insufficient range. Asked for recpie for directing the rust code generator to cope. Upstream changes relative to 1.90.0: Version 1.91.0 (2025-10-30) ========================== Language -------- - [Lower pattern bindings in the order they're written and base drop order on primary bindings' order] (rust-lang/rust#143764) - [Stabilize declaration of C-style variadic functions for `sysv64`, `win64`, `efiapi`, and `aapcs` ABIs] (rust-lang/rust#144066). 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] (rust-lang/rust#144322) - [Upgrade `semicolon_in_expressions_from_macros` from warn to deny] (rust-lang/rust#144369) - [Stabilize LoongArch32 inline assembly] (rust-lang/rust#144402) - [Add warn-by-default `integer_to_ptr_transmutes` lint against integer-to-pointer transmutes] (rust-lang/rust#144531) - [Stabilize `sse4a` and `tbm` target features] (rust-lang/rust#144542) - [Add `target_env = "macabi"` and `target_env = "sim"` cfgs] (rust-lang/rust#139451) as replacements for the `target_abi` cfgs with the same values. Compiler -------- - [Don't warn on never-to-any `as` casts as unreachable] (rust-lang/rust#144804) Platform Support ---------------- - [Promote `aarch64-pc-windows-gnullvm` and `x86_64-pc-windows-gnullvm` to Tier 2 with host tools.] (rust-lang/rust#143031) Note: llvm-tools and MSI installers are missing but will be added in future releases. - [Promote `aarch64-pc-windows-msvc` to Tier 1] (rust-lang/rust#145682) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. [platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html Libraries --------- - [Print thread ID in panic message] (rust-lang/rust#115746) - [Fix overly restrictive lifetime in `core::panic::Location::file` return type] (rust-lang/rust#132087) - [Guarantee parameter order for `_by()` variants of `min` / `max`/ `minmax` in `std::cmp`] (rust-lang/rust#139357) - [Document assumptions about `Clone` and `Eq` traits] (rust-lang/rust#144330) - [`std::thread`: Return error if setting thread stack size fails] (rust-lang/rust#144210) This used to panic within the standard library. Stabilized APIs --------------- - [`Path::file_prefix`] (https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.file_prefix) - [`AtomicPtr::fetch_ptr_add`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_ptr_add) - [`AtomicPtr::fetch_ptr_sub`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_ptr_sub) - [`AtomicPtr::fetch_byte_add`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_byte_add) - [`AtomicPtr::fetch_byte_sub`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_byte_sub) - [`AtomicPtr::fetch_or`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_or) - [`AtomicPtr::fetch_and`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_and) - [`AtomicPtr::fetch_xor`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.fetch_xor) - [`{integer}::strict_add`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_add) - [`{integer}::strict_sub`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_sub) - [`{integer}::strict_mul`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_mul) - [`{integer}::strict_div`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_div) - [`{integer}::strict_div_euclid`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_div_euclid) - [`{integer}::strict_rem`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_rem) - [`{integer}::strict_rem_euclid`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_rem_euclid) - [`{integer}::strict_neg`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_neg) - [`{integer}::strict_shl`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_shl) - [`{integer}::strict_shr`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_shr) - [`{integer}::strict_pow`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_pow) - [`i{N}::strict_add_unsigned`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_add_unsigned) - [`i{N}::strict_sub_unsigned`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_sub_unsigned) - [`i{N}::strict_abs`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.strict_abs) - [`u{N}::strict_add_signed`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_add_signed) - [`u{N}::strict_sub_signed`] (https://doc.rust-lang.org/stable/std/primitive.u32.html#method.strict_sub_signed) - [`PanicHookInfo::payload_as_str`] (https://doc.rust-lang.org/stable/std/panic/struct.PanicHookInfo.html#method.payload_as_str) - [`core::iter::chain`] (https://doc.rust-lang.org/stable/core/iter/fn.chain.html) - [`u{N}::checked_signed_diff`] (https://doc.rust-lang.org/stable/std/primitive.u16.html#method.checked_signed_diff) - [`core::array::repeat`] (https://doc.rust-lang.org/stable/core/array/fn.repeat.html) - [`PathBuf::add_extension`] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.add_extension) - [`PathBuf::with_added_extension`] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.with_added_extension) - [`Duration::from_mins`] (https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_mins) - [`Duration::from_hours`] (https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_hours) - [`impl PartialEq<str> for PathBuf`] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-PartialEq%3Cstr%3E-for-PathBuf) - [`impl PartialEq<String> for PathBuf`] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-PartialEq%3CString%3E-for-PathBuf) - [`impl PartialEq<str> for Path`] (https://doc.rust-lang.org/stable/std/path/struct.Path.html#impl-PartialEq%3Cstr%3E-for-Path) - [`impl PartialEq<String> for Path`] (https://doc.rust-lang.org/stable/std/path/struct.Path.html#impl-PartialEq%3CString%3E-for-Path) - [`impl PartialEq<PathBuf> for String`] (https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-PartialEq%3CPathBuf%3E-for-String) - [`impl PartialEq<Path> for String`] (https://doc.rust-lang.org/stable/std/string/struct.String.html#impl-PartialEq%3CPath%3E-for-String) - [`impl PartialEq<PathBuf> for str`] (https://doc.rust-lang.org/stable/std/primitive.str.html#impl-PartialEq%3CPathBuf%3E-for-str) - [`impl PartialEq<Path> for str`] (https://doc.rust-lang.org/stable/std/primitive.str.html#impl-PartialEq%3CPath%3E-for-str) - [`Ipv4Addr::from_octets`] (https://doc.rust-lang.org/stable/std/net/struct.Ipv4Addr.html#method.from_octets) - [`Ipv6Addr::from_octets`] (https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.from_octets) - [`Ipv6Addr::from_segments`] (https://doc.rust-lang.org/stable/std/net/struct.Ipv6Addr.html#method.from_segments) - [`impl<T> Default for Pin<Box<T>> where Box<T>: Default, T: ?Sized`] (https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CBox%3CT%3E%3E) - [`impl<T> Default for Pin<Rc<T>> where Rc<T>: Default, T: ?Sized`] (https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CRc%3CT%3E%3E) - [`impl<T> Default for Pin<Arc<T>> where Arc<T>: Default, T: ?Sized`] (https://doc.rust-lang.org/stable/std/default/trait.Default.html#impl-Default-for-Pin%3CArc%3CT%3E%3E) - [`Cell::as_array_of_cells`] (https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#method.as_array_of_cells) - [`u{N}::carrying_add`] (https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_add) - [`u{N}::borrowing_sub`] (https://doc.rust-lang.org/stable/std/primitive.u64.html#method.borrowing_sub) - [`u{N}::carrying_mul`] (https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_mul) - [`u{N}::carrying_mul_add`] (https://doc.rust-lang.org/stable/std/primitive.u64.html#method.carrying_mul_add) - [`BTreeMap::extract_if`] (https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.extract_if) - [`BTreeSet::extract_if`] (https://doc.rust-lang.org/stable/std/collections/struct.BTreeSet.html#method.extract_if) - [`impl Debug for windows::ffi::EncodeWide<'_>`] (https://doc.rust-lang.org/stable/std/os/windows/ffi/struct.EncodeWide.html#impl-Debug-for-EncodeWide%3C'_%3E) - [`str::ceil_char_boundary`] (https://doc.rust-lang.org/stable/std/primitive.str.html#method.ceil_char_boundary) - [`str::floor_char_boundary`] (https://doc.rust-lang.org/stable/std/primitive.str.html#method.floor_char_boundary) - [`impl Sum for Saturating<u{N}>`] (https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Sum-for-Saturating%3Cu32%3E) - [`impl Sum<&Self> for Saturating<u{N}>`] (https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Sum%3C%26Saturating%3Cu32%3E%3E-for-Saturating%3Cu32%3E) - [`impl Product for Saturating<u{N}>`] (https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Product-for-Saturating%3Cu32%3E) - [`impl Product<&Self> for Saturating<u{N}>`] (https://doc.rust-lang.org/stable/std/num/struct.Saturating.html#impl-Product%3C%26Saturating%3Cu32%3E%3E-for-Saturating%3Cu32%3E) These previously stable APIs are now stable in const contexts: - [`<[T; N]>::each_ref`] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_ref) - [`<[T; N]>::each_mut`] (https://doc.rust-lang.org/stable/std/primitive.array.html#method.each_mut) - [`OsString::new`] (https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.new) - [`PathBuf::new`] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.new) - [`TypeId::of`] (https://doc.rust-lang.org/stable/std/any/struct.TypeId.html#method.of) - [`ptr::with_exposed_provenance`] (https://doc.rust-lang.org/stable/std/ptr/fn.with_exposed_provenance.html) - [`ptr::with_exposed_provenance_mut`] (https://doc.rust-lang.org/stable/std/ptr/fn.with_exposed_provenance_mut.html) Cargo ----- - 🎉 Stabilize `build.build-dir`. This config sets the directory where intermediate build artifacts are stored. These artifacts are produced by Cargo and rustc during the build process. End users usually won't need to interact with them, and the layout inside `build-dir` is an implementation detail that may change without notice. ([config doc] (https://doc.rust-lang.org/stable/cargo/reference/config.html#buildbuild-dir)) ([build cache doc] (https://doc.rust-lang.org/stable/cargo/reference/build-cache.html)) [#15833](rust-lang/cargo#15833) [#15840](rust-lang/cargo#15840) - The `--target` flag and the `build.target` configuration can now take literal `"host-tuple"` string, which will internally be substituted by the host machine's target triple. [#15838](rust-lang/cargo#15838) [#16003](rust-lang/cargo#16003) [#16032](rust-lang/cargo#16032) Rustdoc ----- - [In search results, rank doc aliases lower than non-alias items with the same name](rust-lang/rust#145100) - [Raw pointers now work in type-based search like references] (rust-lang/rust#145731). This means you can now search for things like `*const u8 ->`, and additionally functions that take or return raw pointers will now display their signature properly in search results. Compatibility Notes ------------------- - [Always require coroutine captures to be drop-live] (rust-lang/rust#144156) - [Apple: Always pass SDK root when linking with `cc`, and pass it via `SDKROOT` env var] (rust-lang/rust#131477). This should fix linking issues with `rustc` running inside Xcode. Libraries in `/usr/local/lib` may no longer be linked automatically, if you develop or use a crate that relies on this, you should explicitly set `cargo::rustc-link-search=/usr/local/lib` in a `build.rs` script. - [Relaxed bounds in associated type bound position like in `TraitRef<AssocTy: ?Sized>` are now correctly forbidden] (rust-lang/rust#135331) - [Add unstable `#[sanitize(xyz = "on|off")]` built-in attribute that shadows procedural macros with the same name] (rust-lang/rust#142681) - [Fix the drop checker being more permissive for bindings declared with let-else] (rust-lang/rust#143028) - [Be more strict when parsing attributes, erroring on many invalid attributes] (rust-lang/rust#144689) - [Error on invalid `#[should_panic]` attributes] (rust-lang/rust#143808) - [Error on invalid `#[link]` attributes] (rust-lang/rust#143193) - [Mark all deprecation lints in name resolution as deny-by-default and also report in dependencies] (rust-lang/rust#143929) - The lint `semicolon_in_expressions_from_macros`, for `macro_rules!` macros in expression position that expand to end in a semicolon (`;`), is now deny-by-default. It was already warn-by-default, and a future compatibility warning (FCW) that warned even in dependencies. This lint will become a hard error in the future. - [Trait impl modifiers (e.g., `unsafe`, `!`, `default`) in inherent impls are no longer syntactically valid] (rust-lang/rust#144386) - [Start reporting future breakage for `ill_formed_attribute_input` in dependencies] (rust-lang/rust#144544) - [Restrict the scope of temporaries created by the macros `pin!`, `format_args!`, `write!`, and `writeln!` in `if let` scrutinees in Rust Edition 2024.] (rust-lang/rust#145342) This applies [Rust Edition 2024's `if let` temporary scope rules] (https://doc.rust-lang.org/edition-guide/rust-2024/temporary-if-let-scope.html) to these temporaries, which previously could live past the `if` expression regardless of Edition. - [Invalid numeric literal suffixes in tuple indexing, tuple struct indexing, and struct field name positions are now correctly rejected] (rust-lang/rust#145463) - [Closures marked with the keyword `static` are now syntactically invalid] (rust-lang/rust#145604) - [Shebangs inside `--cfg` and `--check-cfg` arguments are no longer allowed] (rust-lang/rust#146211) - [Add future incompatibility lint for temporary lifetime shortening in Rust 1.92] (rust-lang/rust#147056) Cargo compatibility notes: - `cargo publish` no longer keeps `.crate` tarballs as final build artifacts when `build.build-dir` is set. These tarballs were previously included due to an oversight and are now treated as intermediate artifacts. To get `.crate` tarballs as final artifacts, use `cargo package`. In a future version, this change will apply regardless of `build.build-dir`. [#15910](rust-lang/cargo#15910) - Adjust Cargo messages to match rustc diagnostic style. This changes some of the terminal colors used by Cargo messages. [#15928](rust-lang/cargo#15928) - Tools and projects relying on the [internal details of Cargo's `build-dir`] (https://doc.rust-lang.org/cargo/reference/build-cache.html) may not work for users changing their `build-dir` layout. For those doing so, we'd recommend proactively testing these cases particularly as we are considering changing the default location of the `build-dir` in the future ([cargo#16147](rust-lang/cargo#16147)). If you can't migrate off of Cargo's internal details, we'd like to learn more about your use case as we prepare to change the layout of the `build-dir` ([cargo#15010] (rust-lang/cargo#15010)). Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Update to LLVM 21](rust-lang/rust#143684)
Most standard library collections break if
Clonehas a non-standard implementation which violatesx.clone() == x. Here the resulting broken behaviour of different collections is shown. I originally created an issue at rust-lang/hashbrown#629, but the conclusion there was thatx.clone()resulting in an object that compares equal to the original one is probably a very universal assumption. However, this assumption is (to my knowledge) not documented anywhere.I propose to make this assumption explicit in the
Clonetrait documentation. The property that seems the most reasonable to me is the following: When implementing bothCloneandPartialEq, thenis expected to hold. This way, when also implementing
Eq, it automatically follows thatx.clone() == xhas to hold, which should be enough for the collections to not break. At the same time, the property also works for the "normal" elements of a type withPartialEq. For the wording, I tried to follow theHashandEqdocumentation.As I am fairly new to Rust, it might well be that this property cannot be generally expected – it seems reasonable to me, but any counter-examples or critique, both content- and wording-wise, would be very welcome. If the property turns out to be too general, I would suggest to at least document the assumption of
x.clone() == xfor the collections somehow.An additional thought of mine:
If it is indeed generally expected that
x == x -> x.clone() == x, then, for the sake of completeness, one could also define thatx != x -> y != y for y = x.clone()should hold, i.e., that an object that did not compare equal to itself before cloning, should also not compare equal to itself afterwards.