Commit Graph

18169 Commits

Author SHA1 Message Date
Matthias Krüger
2dc7573edd
Rollup merge of #137336 - riverbl:stabilise-os-str-display, r=tgross35
Stabilise `os_str_display`

Closes #120048.
2025-02-21 19:01:14 +01:00
Matthias Krüger
4aa973b3e4
Rollup merge of #136609 - mammothbane:master, r=scottmcm
libcore/net: `IpAddr::as_octets()`

[ACP](https://github.com/rust-lang/libs-team/issues/535)
[Tracking issue](https://github.com/rust-lang/rust/issues/137259)

Adds `const` `core::net::IpAddr{,v4,v6}::as_octets()` methods to provide reference access to IP address contents.

The concrete usecase for me is allowing the `IpAddr` to provide an extended lifetime in contexts that want a `&[u8]`:

```rust
trait AddrSlice {
    fn addr_slice(&self) -> &[u8];
}

impl AddrSlice for IpAddrV4 {
    fn addr_slice(&self) -> &[u8] {
        // self.octets() doesn't help us here, because we can't return a reference to the owned array.
        // Instead we want the IpAddrV4 to continue owning the memory:
        self.as_octets()
    }
}
```

(Notably, in this case we can't parameterize `AddrSlice` by a `const N: usize` (such that `fn addr_slice(&self) -> [u8; N]`) and maintain object-safety.)
2025-02-21 19:01:13 +01:00
Matthias Krüger
28164f1229
Rollup merge of #136148 - kpreid:type-str, r=joboet
Optionally add type names to `TypeId`s.

This feature is intended to provide expensive but thorough help for developers who have an unexpected `TypeId` value and need to determine what type it actually is. It causes `impl Debug for TypeId` to print the type name in addition to the opaque ID hash, and in order to do so, adds a name field to `TypeId`. The cost of this is the increased size of `TypeId` and the need to store type names in the binary; therefore, it is an optional feature. It does not expose any new public API, only change the `Debug` implementation.

It may be enabled via `cargo -Zbuild-std -Zbuild-std-features=debug_typeid`. (Note that `-Zbuild-std-features` disables default features which you may wish to reenable in addition; see
<https://doc.rust-lang.org/cargo/reference/unstable.html#build-std-features>.)

Example usage and output:

```
fn main() {
    use std::any::{Any, TypeId};
    dbg!(TypeId::of::<usize>(), drop::<usize>.type_id());
}
```

```
TypeId::of::<usize>() = TypeId(0x763d199bccd319899208909ed1a860c6 = usize)
drop::<usize>.type_id() = TypeId(0xe6a34bd13f8c92dd47806da07b8cca9a = core::mem::drop<usize>)
```

Also added feature declarations for the existing `debug_refcell` feature so it is usable from the `rust.std-features` option of `config.toml`.

Related issues:

* #68379
* #61533
2025-02-21 19:01:12 +01:00
bors
9f48dedc97 Auto merge of #137192 - kornelski:windows-tls-lto, r=ChrisDenton
Remove obsolete Windows ThinLTO+TLS workaround

The bug #109797 has been fixed by #129079, so this workaround is no longer needed.
2025-02-21 11:43:00 +00:00
Jubilee
f24b140976
Rollup merge of #137270 - QianNangong:master, r=ChrisDenton
Fix `*-win7-windows-msvc` target since 26eeac1a1e

That commit make it failed to build `std` with `*-win7-windows-msvc` so fix it.
2025-02-20 14:58:18 -08:00
Jubilee
480a72d601
Rollup merge of #134340 - Urgau:stabilize-num_midpoint_signed, r=scottmcm
Stabilize `num_midpoint_signed` feature

This PR proposes that we stabilize the signed variants of [`iN::midpoint`](https://github.com/rust-lang/rust/issues/110840#issue-1684506201), the operation is equivalent to doing `(a + b) / 2` in a sufficiently large number.

The stabilized API surface would be:

```rust
/// Calculates the middle point of `self` and `rhs`.
///
/// `midpoint(a, b)` is `(a + b) / 2` as if it were performed in a
/// sufficiently-large signed integer type. This implies that the result is
/// always rounded towards zero and that no overflow will ever occur.

impl i{8,16,32,64,128,size} {
    pub const fn midpoint(self, rhs: Self) -> Self;
}
```

T-libs-api previously stabilized the unsigned (and float) variants in #131784, the signed variants were left out because of the rounding that should be used in case of negative midpoint.

This stabilization proposal proposes that we round towards zero because:
 - it makes the obvious `(a + b) / 2` in a sufficiently-large number always true
   - using another rounding for the positive result would be inconsistent with the unsigned variants
 - it makes `midpoint(-a, -b)` == `-midpoint(a, b)` always true
 - it is consistent with `midpoint(a as f64, b as f64) as i64`
 - it makes it possible to always suggest `midpoint` as a replacement for `(a + b) / 2` expressions *(which we may want to do as a future work given the 21.2k hits on [GitHub Search](https://github.com/search?q=lang%3Arust+%2F%5C%28%5Ba-zA-Z_%5D*+%5C%2B+%5Ba-zA-Z_%5D*%5C%29+%5C%2F+2%2F&type=code&p=1))*

`@scottmcm` mentioned a drawback in https://github.com/rust-lang/rust/pull/132191#issuecomment-2439891200:
> I'm torn, because rounding towards zero makes it "wider" than other values, which `>> 1` avoids -- `(a + b) >> 1` has the nice behaviour that `midpoint(a, b) + 2 == midpoint(a + 2, b + 2)`.
>
> But I guess overall sticking with `(a + b) / 2` makes sense as well, and I do like the negation property 🤷

Which I think is outweigh by the advantages cited above.

Closes #110840
cc `@rust-lang/libs-api`
cc `@scottmcm`
r? `@dtolnay`
2025-02-20 14:58:16 -08:00
riverbl
5112ecb8ca Stabilise os_str_display 2025-02-20 19:12:06 +00:00
bors
f04bbc60f8 Auto merge of #136771 - scottmcm:poke-slice-iter-next, r=joboet
Simplify `slice::Iter::next` enough that it inlines

Inspired by this zulip conversation: <https://rust-lang.zulipchat.com/#narrow/channel/189540-t-compiler.2Fwg-mir-opt/topic/Feedback.20on.20a.20MIR.20optimization.20idea/near/498579990>

~~Draft for now because it needs #136735 to get the codegen tests to pass.~~
2025-02-20 18:20:40 +00:00
bors
6d3c050de8 Auto merge of #137295 - matthiaskrgr:rollup-tdu3t39, r=matthiaskrgr
Rollup of 9 pull requests

Successful merges:

 - #135296 (interpret: adjust vtable validity check for higher-ranked types)
 - #137106 (Add customized compare for Link in rustdoc)
 - #137253 (Restrict `bevy_ecs` `ParamSet` hack)
 - #137262 (Make fewer crates depend on `rustc_ast_ir`)
 - #137263 (Register `USAGE_OF_TYPE_IR_INHERENT`, remove inherent usages)
 - #137266 (MIR visitor tweaks)
 - #137269 (Pattern Migration 2024: properly label `&` patterns whose subpatterns are from macro expansions)
 - #137277 (stabilize `inherent_str_constructors`)
 - #137281 (Tweak "expected ident" parse error to avoid talking about doc comments)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-02-20 02:39:28 +00:00
Matthias Krüger
be73ea82ce
Rollup merge of #137277 - m4rch3n1ng:stabilize-inherent-str-constructors, r=tgross35
stabilize `inherent_str_constructors`

fcp done in https://github.com/rust-lang/rust/issues/131114#issuecomment-2668859969.

tracking issue: #131114
closes: #131114
2025-02-20 00:55:16 +01:00
bors
4e1356b959 Auto merge of #137290 - matthiaskrgr:rollup-a7xdbi4, r=matthiaskrgr
Rollup of 8 pull requests

Successful merges:

 - #120580 (Add `MAX_LEN_UTF8` and `MAX_LEN_UTF16` Constants)
 - #132268 (Impl TryFrom<Vec<u8>> for String)
 - #136093 (Match Ergonomics 2024: update old-edition behavior of feature gates)
 - #136344 (Suggest replacing `.` with `::` in more error diagnostics.)
 - #136690 (Use more explicit and reliable ptr select in sort impls)
 - #136815 (CI: Stop /msys64/bin from being prepended to PATH in msys2 shell)
 - #136923 (Lint `#[must_use]` attributes applied to methods in trait impls)
 - #137155 (Organize `OsString`/`OsStr` shims)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-02-19 23:29:37 +00:00
Matthias Krüger
3964bb131b
Rollup merge of #137155 - thaliaarchi:wtf8-organize, r=ChrisDenton
Organize `OsString`/`OsStr` shims

Synchronize the `bytes.rs` and `wtf8.rs` shims for `OsString`/`OsStr` so they're easier to diff between each other. This is mostly ordering items the same between the two. I tried to minimize moves and went for the average locations between the files.

With them in the same order, it is clear that `FromInner<_>` is not implemented for `bytes::Buf` and `Clone::clone_from` is not implemented for `wtf8::Buf`, but they are for the other. Fix that.

I added #[inline] to all inherent methods of the `OsString`/`OsStr` shims, because it seemed that was already the rough pattern. `bytes.rs` has more inlining than `wtf8.rs`, so I added the corresponding ones to `wtf8.rs`. Then, the common missing ones have no discernible pattern to me. They're not divided by non-allocating/allocating. Perhaps the pattern is that UTF-8 validation isn't inlined? Since these types are merely the inner values in `OsStr`/`OsString`, I put inline on all methods and let those public types dictate inlining. I have not inspected codegen or run benchmarks.

Also, touch up some (private) documentation comments.

r? ``````@ChrisDenton``````
2025-02-19 21:16:12 +01:00
Matthias Krüger
c29cc600fd
Rollup merge of #136923 - samueltardieu:push-vxxqvqwspssv, r=davidtwco
Lint `#[must_use]` attributes applied to methods in trait impls

The `#[must_use]` attribute has no effect when applied to methods in trait implementations. This PR adds it to the unused `#[must_use]` lint, and cleans the extra attributes in portable-simd and Clippy.
2025-02-19 21:16:11 +01:00
Matthias Krüger
59d2b102b4
Rollup merge of #136690 - Voultapher:use-more-explicit-and-reliable-ptr-select, r=thomcc
Use more explicit and reliable ptr select in sort impls

Using `if ...` with the intent to avoid branches can be surprising to readers and carries the risk of turning into jumps/branches generated by some future compiler version, breaking crucial optimizations.

This commit replaces their usage with the explicit and IR annotated `bool::select_unpredictable`.
2025-02-19 21:16:09 +01:00
Matthias Krüger
7b7b1d4ee9
Rollup merge of #132268 - elichai:string_try_from_vec, r=Amanieu
Impl TryFrom<Vec<u8>> for String

I think this is useful enough to have :)
As a general question, is there any policy around adding "missing" trait implementations? (like adding `AsRef<T> for T` for std types), I mostly stumble upon them when using a lot of "impl Trait in argument position" like (`foo: impl Into<String>`)
2025-02-19 21:16:02 +01:00
Matthias Krüger
84e9f29007
Rollup merge of #120580 - HTGAzureX1212:HTGAzureX1212/issue-45795, r=m-ou-se
Add `MAX_LEN_UTF8` and `MAX_LEN_UTF16` Constants

This pull request adds the `MAX_LEN_UTF8` and `MAX_LEN_UTF16` constants as per #45795, gated behind the `char_max_len` feature.

The constants are currently applied in the `alloc`, `core` and `std` libraries.
2025-02-19 21:16:01 +01:00
may
b24f77507f
stabilize inherent_str_constructors 2025-02-19 19:24:49 +01:00
Matthias Krüger
ce72b8d91e
Rollup merge of #136794 - cberner:stabilize, r=joshtriplett
Stabilize file_lock

Closes #130994
2025-02-19 18:52:06 +01:00
Matthias Krüger
e6406ad4dd
Rollup merge of #136347 - allevo:patch-1, r=Amanieu
Add a bullet point to `std::fs::copy`

I needed to copy a file but I got the following error:
```
Os { code: 2, kind: NotFound, message: "No such file or directory" }
```
After read the documentation, I though the error was generated by the `from` parameter, forgetting the `to` part. Anyway, I got the error because the parent folder of `to` didn't exist.
Even if the documentation explicitly saying `but is not limited to just these cases`, I would like to add this case because I spent 3 hours around it.

This PR just wants to put a mention about it.
2025-02-19 18:52:05 +01:00
Matthias Krüger
2c1e1bd2cb
Rollup merge of #136301 - hkBst:patch-33, r=thomcc
Improve instant docs

This should be enough to close #79881.
2025-02-19 18:52:04 +01:00
Matthias Krüger
2c380a4661
Rollup merge of #134995 - DaniPopes:stable-const_slice_flatten, r=Amanieu
Stabilize const_slice_flatten

Const-stabilizes `slice::as_flattened{,_mut}`:
```rust
// core::slice
impl<T, const N: usize> [[T; N]] {
    pub const fn as_flattened(&self) -> &[T];
    pub const fn as_flattened_mut(&mut self) -> &mut [T];
}
```

Tracking issue: https://github.com/rust-lang/rust/issues/95629

Requires separate FCP, as per https://github.com/rust-lang/rust/issues/95629#issuecomment-2566546257.

Closes https://github.com/rust-lang/rust/issues/95629.

`````@rustbot````` modify labels: +T-libs-api

Happy new year!
2025-02-19 18:52:03 +01:00
Li Keqing
35febd7a6d Fix *-win7-windows-msvc target since 26eeac1a1e 2025-02-19 18:05:37 +08:00
Tommaso Allevi
3ad847779e
Update library/std/src/fs.rs
Co-authored-by: Amanieu d'Antras <amanieu@gmail.com>
2025-02-19 09:17:18 +01:00
Nathan Perry
8fb888555f core/net: IpAddr*::as_octets()
Adds `const` `Ip*Addr::as_octets` methods providing reference access to
`Ip*Addr` octets contents.

See https://github.com/rust-lang/libs-team/issues/535 for accepted ACP
with a more detailed justification.
2025-02-19 00:50:46 -05:00
Matthias Krüger
e51fae58da
Rollup merge of #137228 - steffahn:one-coerces-to-supertypes-not-subtypes, r=the8472
Fix typo in hidden internal docs of `TrustedRandomAccess`

I typoed the coercion direction here 4 years ago; fixing it now
2025-02-19 01:30:14 +01:00
Matthias Krüger
38fba8ca96
Rollup merge of #137026 - GrigorenkoPV:integer_sign_cast, r=jhpratt
Stabilize (and const-stabilize) `integer_sign_cast`

Tracking issue: #125882
Closes: #125882
FCP completed: https://github.com/rust-lang/rust/issues/125882#issuecomment-2658274124
2025-02-19 01:30:10 +01:00
bors
f44efbf9e1 Auto merge of #137235 - matthiaskrgr:rollup-2kjua2t, r=matthiaskrgr
Rollup of 10 pull requests

Successful merges:

 - #135711 (Do not ICE on default_field_value const with lifetimes)
 - #136599 (librustdoc: more usages of `Joined::joined`)
 - #136876 (Locking documentation updates)
 - #137000 (Deeply normalize item bounds in new solver)
 - #137126 (fix docs for inherent str constructors)
 - #137161 (Pattern Migration 2024: fix incorrect messages/suggestions when errors arise in macro expansions)
 - #137191 (Update mdbook and move error_index_generator)
 - #137203 (Improve MIR modification)
 - #137206 (Make E0599 a structured error)
 - #137218 (misc `layout_of` cleanup)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-02-18 21:08:58 +00:00
Matthias Krüger
ac3b179c3b
Rollup merge of #137126 - m4rch3n1ng:fix-inherent-str-docs, r=Amanieu
fix docs for inherent str constructors

related to #131114

when implementing inherent str constructors in #136517, i forgot to change the docs, so the code examples still imported the `std::str` module and used the constructor from there, instead of using "itself" (the inherent constructor).
2025-02-18 18:40:52 +01:00
Matthias Krüger
5a942d67a6
Rollup merge of #136876 - joshtriplett:locking-might-not-be-advisory, r=Amanieu
Locking documentation updates

- Reword file lock documentation to clarify advisory vs mandatory. Remove the
  word "advisory", and make it more explicit that the lock may be advisory or
  mandatory depending on platform.

- Document that locking a file fails on Windows if the file is opened only for append
2025-02-18 18:40:50 +01:00
Urgau
b7c2da2231
Rollup merge of #137214 - cyrgani:clippy_diagnostic_items, r=compiler-errors
add last std diagnostic items for clippy

Part of https://github.com/rust-lang/rust-clippy/issues/5393.
Add diagnostic item attributes to the items in `std` and `core` where clippy currently uses hardcoded paths (https://github.com/rust-lang/rust-clippy/blob/master/clippy_utils/src/paths.rs).
2025-02-18 18:34:18 +01:00
Urgau
73e5abd175
Rollup merge of #137205 - thaliaarchi:remove-wasi-fileext-tell, r=alexcrichton
Remove `std::os::wasi::fs::FileExt::tell`

Following #137165 (Use `tell` for `<File as Seek>::stream_position`), `tell` is now directly exposed via `stream_position`, making `<File as FileExt>::tell` redundant. Remove it.

`std::os::wasi::fs::FileExt::tell` is currently unstable and tracked in https://github.com/rust-lang/rust/issues/71213.

``@rustbot`` ping wasi
2025-02-18 18:34:17 +01:00
Urgau
14fb84a5bb
Rollup merge of #137167 - martn3:reliable_f16_math-f16-erfc, r=tgross35
tests: Also gate `f16::erfc()` doctest with `reliable_f16_math` cfg

In #136324 the doctest for `f16::erf()` was gated with `reliable_f16_math`. Add the same gate on `f16::erfc()` to avoid:

    rust_out.71e2e529d20ea47d-cgu.0:\
    (.text._ZN8rust_out4main43_doctest_main_library_std_src_f16_rs_1321_017h485f3ffe6bf2a981E+0x38): \
    undefined reference to `__gnu_h2f_ieee'

on MIPS (and maybe other architectures).

r? tgross35
2025-02-18 18:34:15 +01:00
Urgau
d7fe4c0e92
Rollup merge of #136750 - kornelski:ub-bug, r=saethlin
Make ub_check message clear that it's not an assert

I've seen a user assume that their unsound code was *safe*, because ub_check prevented the program from performing the unsafe operation.

This PR makes the panic message clearer that ub_check is a bug detector, not run-time safety protection.
2025-02-18 18:34:13 +01:00
Frank Steffahn
d93926cb5d Fix typo in hidden internal docs of TrustedRandomAccess
I typoed the coercion direction here 4 years ago; fixing it now
2025-02-18 17:54:56 +01:00
Josh Triplett
ec2034d53d Reorder "This lock may be advisory or mandatory." earlier in the lock docs 2025-02-18 17:31:10 +01:00
Josh Triplett
35674eff6f Clarify that locking on Windows also works for files opened with .read(true) 2025-02-18 17:26:33 +01:00
cyrgani
a72402a0f9 add last std diagnostic items for clippy 2025-02-18 10:54:37 +01:00
Thalia Archibald
d2f15971de Remove std::os::wasi::fs::FileExt::tell
Following #137165 (Use `tell` for `<File as Seek>::stream_position`),
`tell` is now directly exposed via `stream_position`, making
`<File as FileExt>::tell` redundant. Remove it.
2025-02-17 20:21:05 -08:00
Kornel
40ecda6a33
Remove obsolete MinGW ThinLTO+TLS workaround
#109797 is fixed
2025-02-17 22:10:25 +00:00
Matthias Krüger
10018d8e10
Rollup merge of #137165 - thaliaarchi:file-tell, r=ChrisDenton
Use `tell` for `<File as Seek>::stream_position`

Some platforms have a more efficient way to get the current offset of the file than by seeking. For example, Wasi has `fd_tell` and SOLID has `SOLID_FS_Ftell`. Implement `<File as Seek>::stream_position()` in terms of those.

I do not use any APIs that were not already used in `std`. Although, the `libc` crate has [`ftell`](https://docs.rs/libc/latest/libc/fn.ftell.html), [`ftello`](https://docs.rs/libc/latest/libc/fn.ftello.html), and [`ftello64`](https://docs.rs/libc/latest/libc/fn.ftello64.html), I do not know platform coverage. It appears that Windows has no `tell`-like API.

I have checked that it builds on each relevant platform.
2025-02-17 17:06:10 +01:00
Thalia Archibald
7112474134 Use tell for <File as Seek>::stream_position 2025-02-17 05:25:14 -08:00
bors
2162e9d4b1 Auto merge of #137164 - matthiaskrgr:rollup-dj5826k, r=matthiaskrgr
Rollup of 7 pull requests

Successful merges:

 - #137095 (Replace some u64 hashes with Hash64)
 - #137100 (HIR analysis: Remove unnecessary abstraction over list of clauses)
 - #137105 (Restrict DerefPure for Cow<T> impl to T = impl Clone, [impl Clone], str.)
 - #137120 (Enable `relative-path-include-bytes-132203` rustdoc-ui test on Windows)
 - #137125 (Re-add missing empty lines in the releases notes)
 - #137145 (use add-core-stubs / minicore for a few more tests)
 - #137149 (Remove SSE ABI from i586-pc-windows-msvc)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-02-17 11:18:33 +00:00
Martin Nordholts
f6485ff617 tests: Also gate f16::erfc() doctest with reliable_f16_math cfg
In 136324 the doctest for `f16::erf()` was gated with
`reliable_f16_math`. Add the same gate on `f16::erfc()` to
avoid:

    rust_out.71e2e529d20ea47d-cgu.0:\
    (.text._ZN8rust_out4main43_doctest_main_library_std_src_f16_rs_1321_017h485f3ffe6bf2a981E+0x38): \
    undefined reference to `__gnu_h2f_ieee'

on MIPS (and maybe other architectures).
2025-02-17 11:59:09 +01:00
Matthias Krüger
fae72a07dd
Rollup merge of #137105 - zachs18:cow-derefpure-restrict, r=Nadrieril
Restrict DerefPure for Cow<T> impl to T = impl Clone, [impl Clone], str.

Fixes #136046

`feature(deref_patterns)` tracking issue: https://github.com/rust-lang/rust/issues/87121

`Cow<'_, T>` should only implement `DerefPure` if its `Deref` impl is pure, which requires `<T::Owned as Borrow<T>>::borrow`  to be pure. This PR restricts `impl DerefPure for Cow<'_, T>` to `T: Sized + Clone`, `T = [U: Clone]`, and `T = str` (for all of whom `<T::Owned as Borrow<T>>::borrow` is implemented in the stdlib and is pure).

cc ``@Nadrieril``

------

An alternate approach would be to introduce a new `unsafe trait BorrowPure<T>` analogous to `DerefPure`  that could be implemented for `T: Sized`, `&T`, `&mut T`, `String`, `Vec`, `Box`, `PathBuf`, `OsString`, etc. https://github.com/rust-lang/rust/compare/master...zachs18:borrow-pure-trait
2025-02-17 06:38:15 +01:00
Matthias Krüger
86f3d525e0
Rollup merge of #137101 - GrigorenkoPV:str-inherent-lint, r=Urgau
`invalid_from_utf8[_unchecked]`: also lint inherent methods

Addressing https://github.com/rust-lang/rust/issues/131114#issuecomment-2646663535

Also corrected a typo: "_an_ invalid literal", not "_a_ invalid literal".
2025-02-17 06:37:38 +01:00
Matthias Krüger
c04801dbb9
Rollup merge of #136844 - thaliaarchi:const-io-error, r=ChrisDenton
Use `const_error!` when possible

Replace usages of `io::Error::new(io::ErrorKind::Variant, "constant string")` with `io::const_error!(io::ErrorKind::Variant, "constant string")` to avoid allocations when possible. Additionally, fix `&&str` error messages in SGX and missing/misplaced trailing commas in `const_error!`.
2025-02-17 06:37:37 +01:00
Thalia Archibald
05e4175d79 Synchronize platform adaptors for OsString/OsStr
* Order items as the average of the two adaptors. Enables easier diffs.
* Consistently apply #[inline].
* Implement FromInner<Vec<u8>> for bytes::Buf.
* Implement Clone::clone_from for wtf8::Buf.
2025-02-16 15:21:46 -08:00
Thalia Archibald
8b1a3a26c7 Simplify control flow with while-let 2025-02-16 15:19:08 -08:00
Thalia Archibald
09dc38f23b Improve WTF-8 comments 2025-02-16 14:43:31 -08:00
Matthias Krüger
f82764f2d9
Rollup merge of #137114 - ChrisDenton:error, r=Noratrieb
Add an example for `std::error::Error`

There is currently no example provided for `std::error::Error` so let's fix that.
2025-02-16 17:14:06 +01:00