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2022-05-01Improve codegen of String::retain method.Loïc BRANSTETT-8/+17
Using unwrap_unchecked helps the optimizer to not generate panicking path, that will never be taken for valid UTF-8 like string. Using encode_utf8 saves us a call to a memcpy, as the optimizer is unable to realize that ch_len <= 4 and so can generate much better assembly code. https://rust.godbolt.org/z/z73ohenfc
2022-05-01std::fmt: Improved list of formatting macrosElias Holzmann-4/+6
Two improvements: 1. write! can not only receive a `io::Write`, but also a `fmt::Write` as first argument. 2. The description texts now contain links to the actual macros for easier navigation.
2022-05-01std::fmt: Removed reference to Formatter::buf and other private fieldsElias Holzmann-3/+3
Formatter::buf is not a public field and therefore isn't very helpful in user- facing documentation. Also, the other public fields of Formatter were made private during stabilization of std::fmt (4af3494bb0) and can now only be read via accessor methods.
2022-05-01std::fmt: Fix the grammar documentationElias Holzmann-2/+7
According to the grammar documented, the format specifier `{: }` should not be legal because of the whitespace it contains. However, in reality, this is perfectly fine because the actual implementation allows spaces before the closing brace. Fixes #71088. Also, the exact meaning of most of the terminal symbols was not specified, for example the meaning of `identifier`.
2022-05-01std::fmt: Added argument index comments to examples for specifying precisionElias Holzmann-6/+6
The examples for specifying the precision have comments explaining which argument the specifier is referring to. However, for implicit positional arguments, the examples simply talk about "next arg". To make it easier for readers to follow the comments, "next arg" was supplemented with the actual resulting argument index.
2022-05-01std::fmt: Fixed documentation for specifying precision via `.*`Elias Holzmann-5/+11
The documentation stated that in case of the syntax `{<arg>:<spec>.*}`, "the `<arg>` part refers to the value to print, and the precision must come in the input preceding `<arg>`". This is not correct: the <arg> part does indeed refer to the value to print, but the precision does not come in the input preciding arg, but in the next implicit input (as if specified with {}). Fixes #96413.
2022-05-01Auto merge of #96078 - udoprog:refcounted-str-to-u8, r=dtolnaybors-0/+38
Implement str to [u8] conversion for refcounted containers This seems motivated to complete the APIs for shared containers since we already have similar allocation-free conversions for strings like `From<Box<[u8]>> for Box<str>`. Insta-stable since it's a new trait impl?
2022-04-30Bump shared_from_str to Rust 1.62.0David Tolnay-2/+2
2022-05-01Auto merge of #95362 - scottmcm:calloc-arrays, r=Mark-Simulacrumbors-1/+8
Support arrays of zeros in Vec's __rust_alloc_zeroed optimization I happened to notice in https://users.rust-lang.org/t/any-advantage-of-box-u64-16-16-16-over-vec-u64/73500/3?u=scottmcm that the calloc optimization wasn't applying to vectors-of-arrays, so here's the easy fix for that.
2022-04-29Auto merge of #96489 - shepmaster:revert-vec-from-array-ref, r=yaahcbors-42/+0
Revert "impl From<&[T; N]> and From<&mut [T; N]> for Vec<T>" This reverts commit 5dd702763ae0e112332a4447171adbed51aeee3d.
2022-04-28Add VecDeque::extend from vec::IntoIter and slice::Iter specializationsPaolo Barbolini-20/+85
2022-04-27Revert "impl From<&[T; N]> and From<&mut [T; N]> for Vec<T>"Jake Goulding-42/+0
This reverts commit 5dd702763ae0e112332a4447171adbed51aeee3d.
2022-04-26Rollup merge of #94022 - jongiddy:cow-into-owned-docs, r=Dylan-DPCGuillaume Gomez-3/+3
Clarify that `Cow::into_owned` returns owned data Two sections of the `Cow::into_owned` docs imply that `into_owned` returns a `Cow`. Clarify that it returns the underlying owned object, either cloned or extracted from the `Cow`.
2022-04-26Rollup merge of #90312 - r00ster91:search, r=Dylan-DPCDylan DPC-8/+20
Fix some confusing wording and improve slice-search-related docs This adds more links between `contains` and `binary_search` because I do think they have some relevant connections. If your (big) slice happens to be sorted and you know it, surely you should be using `[3; 100].binary_search(&5).is_ok()` over `[3; 100].contains(&5)`? This also fixes the confusing "searches this sorted X" wording which just sounds really weird because it doesn't know whether it's actually sorted. It should be but it may not be. The new wording should make it clearer that you will probably want to sort it and in the same sentence it also mentions the related function `contains`. Similarly, this mentions `binary_search` on `contains`' docs. This also fixes some other minor stuff and inconsistencies.
2022-04-25Rollup merge of #96107 - Gumichocopengin8:test/vec-deque, r=Mark-SimulacrumMatthias Krüger-0/+294
[test] Add test cases for untested functions for VecDeque Added test cases of the following functions - get - get_mut - swap - reserve_exact - try_reserve_exact - try_reserve - contains - rotate_left - rotate_right - binary_search - binary_search_by - binary_search_by_key
2022-04-24test: add test cases for VecDequeKeita Nonaka-0/+294
2022-04-19Clarify docs for from_raw_partsjmaargh-3/+8
Original safety explanation for from_raw_parts was unclear on safety for consuming a C string. This clarifies when doing so is safe.
2022-04-19Rollup merge of #96089 - ojeda:no-vec-no_global_oom_handling, r=Mark-SimulacrumDylan DPC-2/+2
`alloc`: make `vec!` unavailable under `no_global_oom_handling` `alloc`: make `vec!` unavailable under `no_global_oom_handling` The `vec!` macro has 3 rules, but two are not usable under `no_global_oom_handling` builds of the standard library (even with a zero size): ```rust let _ = vec![42]; // Error: requires `exchange_malloc` lang_item. let _ = vec![42; 0]; // Error: cannot find function `from_elem`. ``` Thus those two rules should not be available to begin with. The remaining one, with an empty matcher, is just a shorthand for `new()` and may not make as much sense to have alone, since the idea behind `vec!` is to enable `Vec`s to be defined with the same syntax as array expressions. Furthermore, the documentation can be confusing since it shows the other rules. Thus perhaps it is better and simpler to disable `vec!` entirely under `no_global_oom_handling` environments, and let users call `new()` instead: ```rust let _: Vec<i32> = vec![]; let _: Vec<i32> = Vec::new(); ``` Notwithstanding this, a `try_vec!` macro would be useful, such as the one introduced in https://github.com/rust-lang/rust/pull/95051. If the shorthand for `new()` is deemed worth keeping on its own, then it may be interesting to have a separate `vec!` macro with a single rule and different, simpler documentation. Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-04-17Auto merge of #96002 - nnethercote:speed-up-Vec-clear-2, r=m-ou-sebors-1/+12
Speed up Vec::clear(). Currently it just calls `truncate(0)`. `truncate()` is (a) not marked as `#[inline]`, and (b) more general than needed for `clear()`. This commit changes `clear()` to do the work itself. This modest change was first proposed in rust-lang#74172, where the reviewer rejected it because there was insufficient evidence that `Vec::clear()`'s performance mattered enough to justify the change. Recent changes within rustc have made `Vec::clear()` hot within `macro_parser.rs`, so the change is now clearly worthwhile. Although it doesn't show wins on CI perf runs, this seems to be because they use PGO. But not all platforms currently use PGO. Also, local builds don't use PGO, and `truncate` sometimes shows up in an over-represented fashion in local profiles. So local profiling will be made easier by this change. Note that this will also benefit `String::clear()`, because it just calls `Vec::clear()`. Finally, the commit removes the `vec-clear.rs` codegen test. It was added in #52908. From before then until now, `Vec::clear()` just called `Vec::truncate()` with a zero length. The body of Vec::truncate() has changed a lot since then. Now that `Vec::clear()` is doing actual work itself, and not just calling `Vec::truncate()`, it's not surprising that its generated code includes a load and an icmp. I think it's reasonable to remove this test. r? `@m-ou-se`
2022-04-16Rollup merge of #96070 - Gumichocopengin8:test/btree-map, r=thomccDylan DPC-0/+105
[test] Add test cases for untested functions for BTreeMap - add `pop_first()`, `pop_last()`, `get_key_value()` and `try_insert()` test cases
2022-04-16`alloc`: make `vec!` unavailable under `no_global_oom_handling`Miguel Ojeda-2/+2
The `vec!` macro has 3 rules, but two are not usable under `no_global_oom_handling` builds of the standard library (even with a zero size): ```rust let _ = vec![42]; // Error: requires `exchange_malloc` lang_item. let _ = vec![42; 0]; // Error: cannot find function `from_elem`. ``` Thus those two rules should not be available to begin with. The remaining one, with an empty matcher, is just a shorthand for `new()` and may not make as much sense to have alone, since the idea behind `vec!` is to enable `Vec`s to be defined with the same syntax as array expressions. Furthermore, the documentation can be confusing since it shows the other rules. Thus perhaps it is better and simpler to disable `vec!` entirely under `no_global_oom_handling` environments, and let users call `new()` instead: ```rust let _: Vec<i32> = vec![]; let _: Vec<i32> = Vec::new(); ``` Notwithstanding this, a `try_vec!` macro would be useful, such as the one introduced in https://github.com/rust-lang/rust/pull/95051. If the shorthand for `new()` is deemed worth keeping on its own, then it may be interesting to have a separate `vec!` macro with a single rule and different, simpler documentation. Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-04-15Auto merge of #95224 - mjbshaw:patch-1, r=yaahcbors-10/+28
Optimize RcInnerPtr::inc_strong()/inc_weak() instruction count Inspired by this internals thread: https://internals.rust-lang.org/t/rc-optimization-on-64-bit-targets/16362 [The generated assembly is a bit smaller](https://rust.godbolt.org/z/TeTnf6144) and is a more efficient usage of the CPU's instruction cache. `unlikely` doesn't impact any of the small artificial tests I've done, but I've included it in case it might help more complex scenarios when this is inlined.
2022-04-15Rollup merge of #96034 - Gumichocopengin8:test/btree-set, r=Dylan-DPCDylan DPC-0/+56
[test] Add test cases of untested functions for BTreeSet - add [`is_superset()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.is_superset) and [`remove()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.remove) test cases for BTreeSet since these functions has no test cases.
2022-04-15Implement str to [u8] conversion for refcounted containersJohn-John Tedro-0/+38
2022-04-15chore: formattingKeita Nonaka-11/+9
2022-04-15test: add try_insert() test cases for BTreeSetKeita Nonaka-0/+15
2022-04-15test: add get_key_value() test cases for BTreeSetKeita Nonaka-0/+24
2022-04-14test: add pop_first() pop_last() test cases for BTreeSetKeita Nonaka-9/+77
2022-04-14Fix targets not supporting `target_has_atomic = "ptr"`Vadim Petrochenkov-1/+5
2022-04-14library: Use type aliases to make `CStr(ing)` in libcore/liballoc unstableVadim Petrochenkov-6/+8
2022-04-14library: Move `CStr` to libcore, and `CString` to liballocVadim Petrochenkov-1/+1524
2022-04-14Remove use of `#[rustc_deprecated]`Jacob Pratt-1/+1
2022-04-13test: add remove() test cases for BTreeSetKeita Nonaka-0/+20
2022-04-13test: add is_superset test cases for BTreeSetKeita Nonaka-0/+36
2022-04-13Speed up Vec::clear().Nicholas Nethercote-1/+12
Currently it just calls `truncate(0)`. `truncate()` is (a) not marked as `#[inline]`, and (b) more general than needed for `clear()`. This commit changes `clear()` to do the work itself. This modest change was first proposed in rust-lang#74172, where the reviewer rejected it because there was insufficient evidence that `Vec::clear()`'s performance mattered enough to justify the change. Recent changes within rustc have made `Vec::clear()` hot within `macro_parser.rs`, so the change is now clearly worthwhile. Although it doesn't show wins on CI perf runs, this seems to be because they use PGO. But not all platforms currently use PGO. Also, local builds don't use PGO, and `truncate` sometimes shows up in an over-represented fashion in local profiles. So local profiling will be made easier by this change. Note that this will also benefit `String::clear()`, because it just calls `Vec::clear()`. Finally, the commit removes the `vec-clear.rs` codegen test. It was added in #52908. From before then until now, `Vec::clear()` just called `Vec::truncate()` with a zero length. The body of Vec::truncate() has changed a lot since then. Now that `Vec::clear()` is doing actual work itself, and not just calling `Vec::truncate()`, it's not surprising that its generated code includes a load and an icmp. I think it's reasonable to remove this test.
2022-04-11impl const Default for Box<[T]> and Box<str>Josh Stone-4/+12
2022-04-11Rollup merge of #95743 - yaahc:binary-search-clarification, r=Mark-SimulacrumMatthias Krüger-2/+16
Update binary_search example to instead redirect to partition_point Inspired by discussion in the tracking issue for `Result::into_ok_or_err`: https://github.com/rust-lang/rust/issues/82223#issuecomment-1067098167 People are surprised by us not providing a `Result<T, T> -> T` conversion, and the main culprit for this confusion seems to be the `binary_search` API. We should instead redirect people to the equivalent API that implicitly does that `Result<T, T> -> T` conversion internally which should obviate the need for the `into_ok_or_err` function and give us time to work towards a more general solution that applies to all enums rather than just `Result` such as making or_patterns usable for situations like this via postfix `match`. I choose to duplicate the example rather than simply moving it from `binary_search` to partition point because most of the confusion seems to arise when people are looking at `binary_search`. It makes sense to me to have the example presented immediately rather than requiring people to click through to even realize there is an example. If I had to put it in only one place I'd leave it in `binary_search` and remove it from `partition_point` but it seems pretty obviously relevant to `partition_point` so I figured the best option would be to duplicate it.
2022-04-09Rollup merge of #95817 - oconnor663:doc_comment2, r=yaahcDylan DPC-1/+1
hide another #[allow] directive from a docs example This is a repeat for Rc of e0e64a89304de2b34dbafbc6cb354d2be9e67835, which cleaned up the same thing for Arc.
2022-04-09Rework String UTF-8 DocumentationMark Lodato-10/+82
**This Commit** Adds some clarity around indexing into Strings and the constraints driving various decisions there. **Why?** The [`String` documentation][0] mentions how `String`s can't be indexed but `Range` has an implementation for `SliceIndex<str>`. This can be confusing. There are also several statements to explain the lack of `String` indexing: - the inability to index into a `String` is an implication of UTF-8 encoding - indexing into a `String` could not be constant-time with UTF-8 encoding - indexing into a `String` does not have an obvious return type This last statement made sense but the first two seemed contradictory to the documentation around [`SliceIndex<str>`][1] which mention: - one can index into a `String` with a `Range` (also called substring slicing but it uses the same syntax and the method name is `index`) - `Range` indexing into a `String` is constant-time To resolve this seeming contradiction the documentation is reworked to more clearly explain what factors drive the decision to disallow indexing into a `String` with a single number. [0]: https://doc.rust-lang.org/stable/std/string/struct.String.html#utf-8 [1]: https://doc.rust-lang.org/stable/std/slice/trait.SliceIndex.html#impl-SliceIndex%3Cstr%3E
2022-04-08hide another #[allow] directive from a docs exampleJack O'Connor-1/+1
This is a repeat for Rc of e0e64a89304de2b34dbafbc6cb354d2be9e67835, which cleaned up the same thing for Arc.
2022-04-08Add ThinBox type for 1 stack pointer sized heap allocated trait objectsJane Lusby-0/+222
Relevant commit messages from squashed history in order: Add initial version of ThinBox update test to actually capture failure swap to middle ptr impl based on matthieu-m's design Fix stack overflow in debug impl The previous version would take a `&ThinBox<T>` and deref it once, which resulted in a no-op and the same type, which it would then print causing an endless recursion. I've switched to calling `deref` by name to let method resolution handle deref the correct number of times. I've also updated the Drop impl for good measure since it seemed like it could be falling prey to the same bug, and I'll be adding some tests to verify that the drop is happening correctly. add test to verify drop is behaving add doc examples and remove unnecessary Pointee bounds ThinBox: use NonNull ThinBox: tests for size Apply suggestions from code review Co-authored-by: Alphyr <47725341+a1phyr@users.noreply.github.com> use handle_alloc_error and fix drop signature update niche and size tests add cfg for allocating APIs check null before calculating offset add test for zst and trial usage prevent optimizer induced ub in drop and cleanup metadata gathering account for arbitrary size and alignment metadata Thank you nika and thomcc! Update library/alloc/src/boxed/thin.rs Co-authored-by: Josh Triplett <josh@joshtriplett.org> Update library/alloc/src/boxed/thin.rs Co-authored-by: Josh Triplett <josh@joshtriplett.org>
2022-04-08Rollup merge of #95791 - oconnor663:doc_comment, r=thomccDylan DPC-1/+1
hide an #[allow] directive from the Arc::new_cyclic doc example A minor docs cleanup.
2022-04-08Rollup merge of #95579 - Cyborus04:slice_flatten, r=scottmcmDylan DPC-0/+46
Add `<[[T; N]]>::flatten{_mut}` Adds `flatten` to convert `&[[T; N]]` to `&[T]` (and `flatten_mut` for `&mut [[T; N]]` to `&mut [T]`)
2022-04-08add `<[[T; N]]>::flatten`, `<[[T; N]]>::flatten_mut`, and `Vec::<[T; ↵Cyborus04-0/+46
N]>::into_flattened`
2022-04-07hide an #[allow] directive from the Arc::new_cyclic doc exampleJack O'Connor-1/+1
2022-04-07Auto merge of #95678 - pietroalbini:pa-1.62.0-bootstrap, r=Mark-Simulacrumbors-49/+32
Bump bootstrap compiler to 1.61.0 beta This PR bumps the bootstrap compiler to the 1.61.0 beta. The first commit changes the stage0 compiler, the second commit applies the "mechanical" changes and the third and fourth commits apply changes explained in the relevant comments. r? `@Mark-Simulacrum`
2022-04-06add necessary closure for partition_pointJane Lusby-2/+2
2022-04-06Update binary_search example to instead redirect to partition_pointJane Lusby-2/+16
2022-04-05trivial cfg(bootstrap) changesPietro Albini-49/+32
2022-04-06formattingSparkyPotato-1/+1