To remind people like me who forget about it and send PRs to make them different, and to (probably) get a test failure if the code is changed to no longer uphold it.
The "read more" sentence formatted "object safety" as inline code
instead of providing a link to more information. This PR adds a link
to the Reference about this matter, as well as the page regarding trait
objects.
Default panic message should print Box<dyn Any>
Closes#86039
Prior to this patch, the panic message from running the following code would be `thread 'main' panicked at 'Box<Any>'...`
```rust
use std::panic::panic_any;
fn main() {
panic_any(42);
}
```
This patch updates the phrasing to be more consistent. It now instead shows the following panic message:
```
thread 'main' panicked at 'Box<dyn Any>', ...
```
It's a very small fix 😄
Clarify documentation of slice sorting methods
After reading about [this](https://polkadot.network/a-polkadot-postmortem-24-05-2021/), I realized that although the documentation of these methods is not ambiguous in its current state, it is very easy to read it and erroneously assume that their exact behaviour can be relied upon to be deterministic. Although the docs make no guarantees about which index is returned when there are multiple matches, being more explicit about when and how their determinism can be relied upon should help prevent people from making this mistake in the future.
r? ``@steveklabnik``
String::remove_matches O(n^2) -> O(n)
Copy only non-matching bytes. Replace collection of matches into a
vector with iteration over rejections, exploiting the guarantee that we
mutate parts of the haystack that have already been searched over.
r? `@joshtriplett`
Prior to this patch, the default panic message (resulting from calling
`panic_any(42);` for example), would print the following error message:
```
thread 'main' panicked at 'Box<Any>', ...
```
However, this should be `Box<dyn Any>` instead.
Update standard library for IntoIterator implementation of arrays
This PR partially resolves issue #84513 of updating the standard library part.
I haven't found any remaining doctest examples which are using iterators over e.g. &i32 instead of just i32 in the standard library. Can anyone point me to them if there's remaining any?
Thanks!
r? ```@m-ou-se```
Show test type during prints
Test output can sometimes be confusing. For example doctest with the no_run argument are displayed the same way than test that are run.
During #83857 I got the feedback that test output can be confusing.
For the moment test output is
```
test $DIR/test-type.rs - f (line 12) ... ignored
test $DIR/test-type.rs - f (line 15) ... ok
test $DIR/test-type.rs - f (line 21) ... ok
test $DIR/test-type.rs - f (line 6) ... ok
```
I propose to change output by indicating the test type as
```
test $DIR/test-type.rs - f (line 12) ... ignored
test $DIR/test-type.rs - f (line 15) - compile ... ok
test $DIR/test-type.rs - f (line 21) - compile fail ... ok
test $DIR/test-type.rs - f (line 6) ... ok
```
by indicating the test type after the test name (and in the case of doctest after the function name and line) and before the "...".
------------
Note: this is a proof of concept, the implementation is probably not optimal as the properties added in `TestDesc` are only use in the display and does not represent actual change of behavior, maybe `TestType::DocTest` could have fields
Possible errors when accessing file metadata are platform specific
In particular the `is_dir`, `is_file` and `exists` functions suggests that querying a file requires querying the directory. On Windows this is not normally true.
r? `@m-ou-se`
Add a map method to Bound
Add a map method to std::ops::range::Bound, patterned off of the method
of the same name on Option.
Have left off creating a tracking issue initially, but as soon as I get the go-ahead from a reviewer I'll make that right away 😄
Remove `doc(include)`
This nightly feature is redundant now that `extended_key_value_attributes` is stable (https://github.com/rust-lang/rust/pull/83366). `@rust-lang/rustdoc` not sure if you think this needs FCP; there was already an FCP in #82539, but technically it was for deprecating, not removing the feature altogether.
This should not be merged before #83366.
cc `@petrochenkov`
rustdoc: link to stable/beta docs consistently in documentation
This is an alternative to https://github.com/rust-lang/rust/pull/84941 which fixes the problem consistently by linking to stable/beta for *all* items, not just for primitives.
## User-facing changes
- Intra-doc links to primitives that currently go to rust-lang.org/nightly/std/primitive.x.html will start going to channel that rustdoc was built with. Nightly will continue going to /nightly; Beta will link to /beta; stable compilers will link to /1.52.1 (or whatever version they were built as).
- Cross-crate links from std to core currently go to /nightly unconditionally. They will start going to /1.52.0 on stable channels (but remain the same on nightly channels).
- Intra-crate links from std to std (or core to core) currently go to the same URL they are hosted at; they will continue to do so. Notably, this is different from everything else because it can preserve the distinction between /stable and /1.52.0 by using relative links.
Note that "links" includes both intra-doc links and rustdoc's own
automatically generated hyperlinks.
## Implementation changes
- Update the testsuite to allow linking to /beta and /1.52.1 in docs
- Use an html_root_url for the standard library that's dependent on the channel
This avoids linking to nightly docs on stable.
- Update rustdoc to use channel-dependent links for primitives from an
unknown crate
- Set DOC_RUST_LANG_ORG_CHANNEL from bootstrap to ensure it's in sync
- Include doc.rust-lang.org in the channel
cc Mark-Simulacrum - I know [you were dubious about this in the past](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/Rustdoc.20unconditionally.20links.20to.20nightly.20libstd.20docs/near/231223124), but I'm not quite sure why? I see this as "just a bugfix", I don't know why rustdoc should unconditionally link to nightly.
cc dtolnay who commented in https://github.com/rust-lang/rust/issues/30693:
> I would welcome a PR to solve this permanently if anyone has ideas for how. I don't believe we need an RFC.
Fixes https://github.com/rust-lang/rust/issues/30693 (note that issue is marked as feature-accepted, although I don't see where it was discussed).
## User-facing changes
- Intra-doc links to primitives that currently go to rust-lang.org/nightly/std/primitive.x.html will start going to channel that rustdoc was built with. Nightly will continue going to /nightly; Beta will link to /beta; stable compilers will link to /1.52.1 (or whatever version they were built as).
- Cross-crate links from std to core currently go to /nightly unconditionally. They will start going to /1.52.0 on stable channels (but remain the same on nightly channels).
- Intra-crate links from std to std (or core to core) currently go to the same URL they are hosted at; they will continue to do so. Notably, this is different from everything else because it can preserve the distinction between /stable and /1.52.0 by using relative links.
Note that "links" includes both intra-doc links and rustdoc's own
automatically generated hyperlinks.
## Implementation changes
- Update the testsuite to allow linking to /beta and /1.52.1 in docs
- Use an html_root_url for the standard library that's dependent on the channel
This avoids linking to nightly docs on stable.
- Update rustdoc to use channel-dependent links for primitives from an
unknown crate
- Set DOC_RUST_LANG_ORG_CHANNEL from bootstrap to ensure it's in sync
- Include doc.rust-lang.org in the channel
Support Android ndk versions `r23-beta3` and up
Since android ndk version `r23-beta3`, `libgcc` has been replaced with `libunwind`. This moves the linking of `libgcc`/`libunwind` into the `unwind` crate where we check if the system compiler can find `libunwind` and fall back to `libgcc` if needed.
Stabilize `vecdeque_binary_search`
This PR stabilizes the feature `vecdeque_binary_search` as tracked in #78021.
The tracking issue has not received any comments for the past 5 months, and concerns have been raised neither in the RFC rust-lang/rfcs#2997 nor in the tracking issue #78021.
Since android ndk version `r23-beta3`, `libgcc` has been replaced with
`libunwind`. This moves the linking of `libgcc`/`libunwind` into the
`unwind` crate where we check if the system compiler can find
`libunwind` and fall back to `libgcc` if needed.
Mention "null pointer optimization" in option docs.
I had seen people discuss "null pointer optimization," but when I tried to find official documentation (using Google), the `std::option` page didn't show up, because it doesn't use that term. Hopefully adding the term will help others find it in the future.
- Split `sys_common::RWLock` between `StaticRWLock` and `MovableRWLock`
- Unbox `RwLock` on some platforms (Windows, Wasm and unsupported)
- Simplify `RwLock::into_inner`
Remove `Ipv6Addr::is_unicast_link_local_strict`
Removes the unstable method `Ipv6Addr::is_unicast_link_local_strict` and keeps the behaviour of `Ipv6Addr::is_unicast_link_local`, see also #85604 where I have tried to summarize related discussion so far.
My intent is for `is_unicast_link_local`, `is_unicast_site_local` and `is_unicast_global` to have the semantics of checking if an address has Link-Local, Site-Local or Global scope, see also #85696 which changes the behaviour of `is_unicast_global` and renames these methods to `has_unicast_XXX_scope` to reflect this.
For checking Link-Local scope we currently have two methods: `is_unicast_link_local` and `is_unicast_link_local_strict`. This is because of what appears to be conflicting definitions in [IETF RFC 4291](https://datatracker.ietf.org/doc/html/rfc4291).
From [IETF RFC 4291 section 2.4](https://datatracker.ietf.org/doc/html/rfc4291#section-2.4): "Link-Local unicast" (`FE80::/10`)
```text
Address type Binary prefix IPv6 notation Section
------------ ------------- ------------- -------
Unspecified 00...0 (128 bits) ::/128 2.5.2
Loopback 00...1 (128 bits) ::1/128 2.5.3
Multicast 11111111 FF00::/8 2.7
Link-Local unicast 1111111010 FE80::/10 2.5.6
Global Unicast (everything else)
```
From [IETF RFC 4291 section 2.5.6](https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.6): "Link-Local IPv6 Unicast Addresses" (`FE80::/64`)
```text
| 10 bits | 54 bits | 64 bits |
+----------+-------------------------+----------------------------+
|1111111010| 0 | interface ID |
+----------+-------------------------+----------------------------+
```
With `is_unicast_link_local` checking `FE80::/10` and `is_unicast_link_local_strict` checking `FE80::/64`.
There is also [IETF RFC 5156 section 2.4](https://datatracker.ietf.org/doc/html/rfc5156#section-2.4) which defines "Link-Scoped Unicast" as `FE80::/10`.
It has been pointed out that implementations in other languages and the linux kernel all use `FE80::/10` (https://github.com/rust-lang/rust/pull/76098#issuecomment-706916840, https://github.com/rust-lang/rust/pull/76098#issuecomment-705928605).
Given all of this I believe the correct interpretation to be the following: All addresses in `FE80::/10` are defined as having Link-Local scope, however currently only the block `FE80::/64` has been allocated for "Link-Local IPv6 Unicast Addresses". This might change in the future however; more addresses in `FE80::/10` could be allocated and those will have Link-Local scope. I therefore believe the current behaviour of `is_unicast_link_local` to be correct (if interpreting it to have the semantics of `has_unicast_link_local_scope`) and `is_unicast_link_local_strict` to be unnecessary, confusing and even a potential source of future bugs:
Currently there is no real difference in checking `FE80::/10` or `FE80::/64`, since any address in practice will be `FE80::/64`. However if an application uses `is_unicast_link_local_strict` to implement link-local (so non-global) behaviour, it will be incorrect in the future if addresses outside of `FE80::/64` are allocated.
r? `@joshtriplett` as reviewer of all the related PRs
Add `String::extend_from_within`
This PR adds `String::extend_from_within` function under the `string_extend_from_within` feature gate similar to the [`Vec::extend_from_within`] function.
```rust
// String
pub fn extend_from_within<R>(&mut self, src: R)
where
R: RangeBounds<usize>;
```
[`Vec::extend_from_within`]: https://github.com/rust-lang/rust/issues/81656
Revert "Auto merge of #83770 - the8472:tra-extend, r=Mark-Simulacrum"
Due to a performance regression that didn't show up in the original perf run
this reverts commit 9111b8ae97 (#83770), reversing
changes made to 9a700d2947.
Since since is expected to have the inverse impact it should probably be rollup=never.
r? `@Mark-Simulacrum`
Make `Step` trait safe to implement
This PR makes a few modifications to the `Step` trait that I believe better position it for stabilization in the short term. In particular,
1. `unsafe trait TrustedStep` is introduced, indicating that the implementation of `Step` for a given type upholds all stated invariants (which have remained unchanged). This is gated behind a new `trusted_step` feature, as stabilization is realistically blocked on min_specialization.
2. The `Step` trait is internally specialized on the `TrustedStep` trait, which avoids a serious performance regression.
3. `TrustedLen` is implemented for `T: TrustedStep` as the latter's invariants subsume the former's.
4. The `Step` trait is no longer `unsafe`, as the invariants must not be relied upon by unsafe code (unless the type implements `TrustedStep`).
5. `TrustedStep` is implemented for all types that implement `Step` in the standard library and compiler.
6. The `step_trait_ext` feature is merged into the `step_trait` feature. I was unable to find any reasoning for the features being split; the `_unchecked` methods need not necessarily be stabilized at the same time, but I think it is useful to have them under the same feature flag.
All existing implementations of `Step` will be broken, as it is not possible to `unsafe impl` a safe trait. Given this trait only exists on nightly, I feel this breakage is acceptable. The blanket `impl<T: Step> TrustedLen for T` will likely cause some minor breakage, but this should be covered by the equivalent impl for `TrustedStep`.
Hopefully these changes are sufficient to place `Step` in decent position for stabilization, which would allow user-defined types to be used with `a..b` syntax.
copy_from_slice generally falls back to memcpy/memmove, which is much more expensive
than we need to write a single element in.
This saves 0.26% instructions on the diesel benchmark.
To make way for a new IoSlice(Mut)::advance function that advances a
single slice.
Also changes the signature to accept a `&mut &mut [IoSlice]`, not
returning anything. This will better match the future IoSlice::advance
function.
This patch adds `String::extend_from_within` function under the
`string_extend_from_within` feature gate similar to the
`Vec::extend_from_within` function.
Add #[track_caller] to panic_any
Report the panic location from the user code.
```rust
use std::panic;
use std::panic::panic_any;
fn main() {
panic::set_hook(Box::new(|panic_info| {
if let Some(location) = panic_info.location() {
println!(
"panic occurred in file '{}' at line {}",
location.file(),
location.line(),
);
} else {
println!("panic occurred but can't get location information...");
}
}));
panic_any(42);
}
````
Before:
`panic occurred in file '/rustc/ff2c947c00f867b9f012e28ba88cecfbe556f904/library/std/src/panic.rs' at line 59`
After:
`panic occurred in file 'src/main.rs' at line 17`
In particular the `is_dir`, `is_file` and `exists` functions says that querying a file requires querying the directory. On Windows this is not normally true.
Mention workaround for floats in Iterator::{min, max}
`Iterator::{min, max}` can't be used with iterators of floats due to NaN issues. This suggests a workaround in the documentation of those functions.
Forwarding `clone_from` to the inner value changes the observable
behavior, as previously the inner value would *not* be dropped by the
default implementation.
Enable Vec's calloc optimization for Option<NonZero>
Someone on discord noticed that `vec![None::<NonZeroU32>; N]` wasn't getting the optimization, so here's a PR 🙃
We can certainly do this in the standard library because we know for sure this is ok, but I think it's also a necessary consequence of documented guarantees like those in https://doc.rust-lang.org/std/option/#representation and https://doc.rust-lang.org/core/num/struct.NonZeroU32.html
It feels weird to do this without adding a test, but I wasn't sure where that would belong. Is it worth adding codegen tests for these?
libunwind fix and cleanup
Fix:
1. "system-llvm-libunwind" now only skip build-script for linux target
2. workaround from https://github.com/rust-lang/rust/pull/65972 is not needed, upstream fix it in 68c50708d1 ( LLVM 11 )
3. remove code for MSCV and Apple in `compile()`, as they are not used
4. fix https://github.com/rust-lang/rust/issues/69222 , compile c files and cpp files in different config
5. fix conditional compilation for musl target.
6. fix that x86_64-fortanix-unknown-sgx don't link libunwind built in build-script into rlib
Add inline attr to CString::into_inner so it can optimize out NonNull checks
It seems that currently if you convert any of the standard library's container to a pointer and then to a NonNull pointer, all will optimize out the NULL check except `CString`(https://godbolt.org/z/YPKW9G5xn),
because for some reason `CString::into_inner` isn't inlined even though it's a private function that should compile into a simple `mov` instruction.
Adding a simple `#[inline]` attribute solves this, code example:
```rust
use std::ffi::CString;
use std::ptr::NonNull;
pub fn cstring_nonull(mut n: CString) -> NonNull<i8> {
NonNull::new(CString::into_raw(n)).unwrap()
}
```
assembly before:
```asm
__ZN3wat14cstring_nonull17h371c755bcad76294E:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset %rbp, -16
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
callq __ZN3std3ffi5c_str7CString10into_inner17h28ece07b276e2878E
testq %rax, %rax
je LBB0_2
popq %rbp
retq
LBB0_2:
leaq l___unnamed_1(%rip), %rdi
leaq l___unnamed_2(%rip), %rdx
movl $43, %esi
callq __ZN4core9panicking5panic17h92a83fa9085a8f73E
.cfi_endproc
.section __TEXT,__const
l___unnamed_1:
.ascii "called `Option::unwrap()` on a `None` value"
l___unnamed_3:
.ascii "wat.rs"
.section __DATA,__const
.p2align 3
l___unnamed_2:
.quad l___unnamed_3
.asciz "\006\000\000\000\000\000\000\000\006\000\000\000(\000\000"
```
Assembly after:
```asm
__ZN3wat14cstring_nonull17h9645eb9341fb25d7E:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset %rbp, -16
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
movq %rdi, %rax
popq %rbp
retq
.cfi_endproc
```
(Related discussion on zulip: https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/NonNull.20From.3CBox.3CT.3E.3E)
Remove Iterator #[rustc_on_unimplemented]s that no longer apply.
Now that `IntoIterator` is implemented for arrays, all the `rustc_on_unimplemented` for arrays of ranges (e.g. `for _ in [1..3] {}`) no longer apply, since they are now valid Rust.
Separated these from #85670, because we should discuss a potential new (clippy?) lint for these.
Until Rust 1.52, `for _ in [1..3] {}` produced:
```
error[E0277]: `[std::ops::Range<{integer}>; 1]` is not an iterator
--> src/main.rs:2:14
|
2 | for _ in [1..3] {}
| ^^^^^^ if you meant to iterate between two values, remove the square brackets
|
= help: the trait `std::iter::Iterator` is not implemented for `[std::ops::Range<{integer}>; 1]`
= note: `[start..end]` is an array of one `Range`; you might have meant to have a `Range` without the brackets: `start..end`
= note: required by `std::iter::IntoIterator::into_iter`
```
But in Rust 1.53 and later, it compiles fine. It iterates over the array by value, for one iteration with the element `1..3`.
This is probably a mistake, which is no longer caught. Should we have a lint for it? Should Clippy have a lint for it?
cc ```@estebank``` ```@flip1995```
cc https://github.com/rust-lang/rust/issues/84513
Update cc
Recent commits have improved `cc`'s finding of MSVC tools on Windows. In particular it should help to address these issues: #83043 and #43468
While stdlib implementations of the unchecked methods require unchecked
math, there is no reason to gate it behind this for external users. The
reasoning for a separate `step_trait_ext` feature is unclear, and as
such has been merged as well.
Add `TrustedRandomAccess` specialization for `Vec::extend()`
This should do roughly the same as the `TrustedLen` specialization but result in less IR by using `__iterator_get_unchecked`
instead of `Iterator::for_each`
Conflicting specializations are manually prioritized by grouping them under yet another helper trait.
Fix typo in core::array::IntoIter comment
Saw a small typo reading some internal comments and decided to just throw this up to fix it for future readers.
Remove num_as_ne_bytes feature
From the discussion in #76976, it is determined that eventual results of the safe transmute work as a more general mechanism will let these conversions happen in safe code without needing specialized methods.
Merging this PR closes#76976 and resolves#64464. Several T-libs members have raised their opinion that it doesn't pull its weight as a standalone method, and so we should not track it as a specific thing to add.
fix `matches!` and `assert_matches!` on edition 2021
Previously this code failed to compile on edition 2021. [(Playground)](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=53960f2f051f641777b9e458da747707)
```rust
fn main() {
matches!((), ());
}
```
```
Compiling playground v0.0.1 (/playground)
error: `$pattern:pat` may be followed by `|`, which is not allowed for `pat` fragments
|
= note: allowed there are: `=>`, `,`, `=`, `if` or `in`
error: aborting due to previous error
error: could not compile `playground`
To learn more, run the command again with --verbose.
```
Demote `ControlFlow::{from|into}_try` to `pub(crate)`
They have mediocre names and non-obvious semantics, so personally I don't think they're worth trying to stabilize, and thus might as well just be internal (they're used for convenience in iterator adapters), not something shown in the rustdocs.
I don't think anyone actually wanted to use them outside `core` -- they just got made public-but-unstable along with the whole type in https://github.com/rust-lang/rust/pull/76204 that promoted `LoopState` from an internal type to the exposed `ControlFlow` type.
cc https://github.com/rust-lang/rust/issues/75744, the tracking issue they mention.
cc https://github.com/rust-lang/rust/pull/85608, the PR where I'm proposing stabilizing the type.
Fix pointer provenance in <[T]>::copy_within
Previously the `self.as_mut_ptr()` invalidated the pointer created by the first `self.as_ptr()`. This also triggered miri when run with `-Zmiri-track-raw-pointers`
doc: clarify Mutex::try_lock, etc. errors
Clarify error returns from Mutex::try_lock, RwLock::try_read,
RwLock::try_write to make it more obvious that both poisoning
and the lock being already locked are possible errors.
Weak's type parameter may dangle on drop
Way back in 34076bc0c9, #\[may_dangle\] was added to Rc\<T\> and Arc\<T\>'s Drop impls. That appears to have been because a test added in #28929 used Arc and Rc with dangling references at drop time. However, Weak was not covered by that test, and therefore no #\[may_dangle\] was forced to be added at the time.
As far as dropping, Weak has *even less need* to interact with the T than Rc and Arc do. Roughly speaking #\[may_dangle\] describes generic parameters that the outer type's Drop impl does not interact with except by possibly dropping them; no other interaction (such as trait method calls on the generic type) is permissible. It's clear this applies to Rc's and Arc's drop impl, which sometimes drop T but otherwise do not interact with one. It applies *even more* to Weak. Dropping a Weak cannot ever cause T's drop impl to run. Either there are strong references still in existence, in which case better not drop the T. Or there are no strong references still in existence, in which case the T would already have been dropped previously by the drop of the last strong count.
Better English for documenting when to use unimplemented!()
I don't think "plan of using" is correct here. I considered "plan on using" but eventually decided "plan to use" is better.
Bump bootstrap compiler to beta 1.53.0
This PR bumps the bootstrap compiler to version 1.53.0 beta, as part of our usual release process (this was supposed to be Wednesday's step, but creating the beta release took longer than expected).
The PR also includes the "Bootstrap: skip rustdoc fingerprint for building docs" commit, see the reasoning [on Zulip](https://zulip-archive.rust-lang.org/241545trelease/88450153betabootstrap.html).
r? `@Mark-Simulacrum`
Extend `rustc_on_implemented` to improve more `?` error messages
`_Self` could match the generic definition; this adds that functionality for matching the generic definition of type parameters too.
Your advice welcome on the wording of all these messages, and which things belong in the message/label/note.
r? `@estebank`
fix pad_integral example
pad_integral's parameter `is_nonnegative - whether the original integer was either positive or zero`, but in example it checked as `self.nb > 0`, so it previously printed `-0` for `format!("{}", Foo::new(0)`, what is wrong.
