Don't panic in ceil_char_boundary
Implementing the alternative mentioned in this comment: https://github.com/rust-lang/rust/issues/93743#issuecomment-1579935853
Since `floor_char_boundary` will always work (rounding down to the length of the string is possible), it feels best for `ceil_char_boundary` to not panic either. However, the semantics of "rounding up" past the length of the string aren't very great, which is why the method originally panicked in these cases.
Taking into account how people are using this method, it feels best to simply return the end of the string in these cases, so that the result is still a valid char boundary.
* remove `impl Provider for Error`
* rename `Demand` to `Request`
* update docstrings to focus on the conceptual API provided by `Request`
* move `core::any::{request_ref, request_value}` functions into `core::error`
* move `core::any::tag`, `core::any::Request`, an `core::any::TaggedOption` into `core::error`
* replace `provide_any` feature name w/ `error_generic_member_access`
* move `core::error::request_{ref,value} tests into core::tests::error module
* update unit and doc tests
Fix documentation of impl From<Vec<T>> for Rc<[T]>
The example in the documentation of `impl From<Vec<T>> for <Rc<[T]>` is irrelevant (likely was copied from `impl From<Box<T>> for <Rc<T>`). I suggest taking corresponding example from the documentation of `Arc` and replacing `Arc` with `Rc`.
It lints against features that are inteded to be internal to the
compiler and standard library. Implements MCP #596.
We allow `internal_features` in the standard library and compiler as those
use many features and this _is_ the standard library from the "internal to the compiler and
standard library" after all.
Marking some features as internal wasn't exactly the most scientific approach, I just marked some
mostly obvious features. While there is a categorization in the macro,
it's not very well upheld (should probably be fixed in another PR).
We always pass `-Ainternal_features` in the testsuite
About 400 UI tests and several other tests use internal features.
Instead of throwing the attribute on each one, just always allow them.
There's nothing wrong with testing internal features^^
Improve test case for experimental API remove_matches
## Add Test Cases for `remove_matches` Function
### Motivation
After reading the discussion in [this GitHub thread](https://github.com/rust-lang/rust/pull/71780), I'm trying to redesign the current API to use less memory when working with `String` and to make it simpler. I've discovered that some test cases are very helpful in ensuring that the new API behaves as intended. I'm still in the process of redesigning the current API, and these test cases have proven to be very useful.
### Testing
The current test has been tested with the command `./x test --stage 0 library/alloc`.
### Overview
This pull request adds several new test cases for the `remove_matches` function to make sure it works correctly in different situations. The `remove_matches` function is used to get rid of all instances of a specific pattern from a given text. These test cases thoroughly check how the function behaves in various scenarios.
### Test Cases
1. **Single Pattern Occurrence** (`test_single_pattern_occurrence`):
- Description: Tests the removal of a single pattern occurrence from the text.
- Input: Text: "abc", Pattern: 'b'
- Expected Output: "ac"
2. **Repeat Test Single Pattern Occurrence** (`repeat_test_single_pattern_occurrence`):
- Description: Repeats the previous test case to ensure consecutive removal of the same pattern.
- Input: Text: "ac", Pattern: 'b'
- Expected Output: "ac"
3. **Single Character Pattern** (`test_single_character_pattern`):
- Description: Tests the removal of a single character pattern.
- Input: Text: "abcb", Pattern: 'b'
- Expected Output: "ac"
4. **Pattern with Special Characters** (`test_pattern_with_special_characters`):
- Description: Tests the removal of a pattern containing special characters.
- Input: Text: "ศไทย中华Việt Nam; foobarศ", Pattern: 'ศ'
- Expected Output: "ไทย中华Việt Nam; foobar"
5. **Pattern Empty Text and Pattern** (`test_pattern_empty_text_and_pattern`):
- Description: Tests the removal of an empty pattern from an empty text.
- Input: Text: "", Pattern: ""
- Expected Output: ""
6. **Pattern Empty Text** (`test_pattern_empty_text`):
- Description: Tests the removal of a pattern from an empty text.
- Input: Text: "", Pattern: "something"
- Expected Output: ""
7. **Empty Pattern** (`test_empty_pattern`):
- Description: Tests the behavior of removing an empty pattern from the text.
- Input: Text: "Testing with empty pattern.", Pattern: ""
- Expected Output: "Testing with empty pattern."
8. **Multiple Consecutive Patterns 1** (`test_multiple_consecutive_patterns_1`):
- Description: Tests the removal of multiple consecutive occurrences of a pattern.
- Input: Text: "aaaaa", Pattern: 'a'
- Expected Output: ""
9. **Multiple Consecutive Patterns 2** (`test_multiple_consecutive_patterns_2`):
- Description: Tests the removal of a longer pattern that occurs consecutively.
- Input: Text: "Hello **world****today!**", Pattern: "**"
- Expected Output: "Hello worldtoday!"
10. **Case Insensitive Pattern** (`test_case_insensitive_pattern`):
- Description: Tests the removal of a case-insensitive pattern from the text.
- Input: Text: "CASE ** SeNsItIvE ** PaTtErN.", Pattern: "sEnSiTiVe"
- Expected Output: "CASE ** SeNsItIvE ** PaTtErN."
Stabilize const-weak-new
This is a fairly uncontroversial library stabilization, so I'm going ahead and proposing it to ride the trains to stable.
This stabilizes the following APIs, which are defined to be non-allocating constructors.
```rust
// alloc::rc
impl<T> Weak<T> {
pub const fn new() -> Weak<T>;
}
// alloc::sync
impl<T> Weak<T> {
pub const fn new() -> Weak<T>;
}
```
Closes#95091
``@rustbot`` modify labels: +needs-fcp
Bump its stabilization version several times along
the way to accommodate changes in release processes.
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Co-authored-by: Trevor Gross <t.gross35@gmail.com>
Documentation: Fix Stilted Language in Vec->Indexing
Problem
Language in the Vec->Indexing documentation sounds stilted due to incorrect word ordering: "... type allows to access values by index."
Solution
Reorder words in the Vec->Indexing documentation to flow better: "... type allows access to values by index." The phrase "allows access to" also matches other existing documentation.
Clarify behavior of inclusive bounds in BTreeMap::{lower,upper}_bound
It wasn’t quite clear to me how these methods would interpret inclusive bounds so I added examples for those.
Remove redundant example of `BTreeSet::iter`
The usage and that `Values returned by the iterator are returned in ascending order` are already demonstrated by the other example and the description, so I removed the useless one.
Problem
Language in the Vec->Indexing documentation sounds stilted due to
incorrect word ordering: "... type allows to access values by index."
Solution
Reorder words in the Vec->Indexing documentation to flow better:
"... type allows access to values by index." The phrase "allows access to"
also matches other existing documentation.
The status quo is highly confusing, since the overlap is not apparent,
and specialization is not a feature of Rust. This addresses #87545;
I'm not certain if it closes it, since that issue might also be trackign
a *general* solution for hiding specializing impls automatically.
Multibyte character removal in String::pop and String::remove doctests
I think it would be useful to have the doctests for the `String::pop()` and `String::remove()` methods demonstrate that they work on multibyte UTF-8 sequences.
Fix size_hint for EncodeUtf16
More realistic upper and lower bounds, and handle the case where the iterator is located within a surrogate pair.
Resolves#113897
Add support for allocators in `Rc` & `Arc`
Adds the ability for `std::rc:Rc`, `std::rc::Weak`, `std::sync::Arc`, and `std::sync::Weak` to live in custom allocators
Rename VecDeque's `rotate_left` and `rotate_right` parameters
This pull request introduces a modification to the `VecDeque` collection, specifically the `rotate_left` and `rotate_right` functions, by renaming the parameter associated with these functions.
The rationale behind this change is to provide clearer and more consistent naming for the parameter that specifies the number of places to rotate the double-ended queue. By using `n` as the parameter name in both functions, it becomes easier to understand and remember the purpose of the parameter.
Eliminate ZST allocations in `Box` and `Vec`
This PR fixes 2 issues with `Box` and `RawVec` related to ZST allocations. Specifically, the `Allocator` trait requires that:
- If you allocate a zero-sized layout then you must later deallocate it, otherwise the allocator may leak memory.
- You cannot pass a ZST pointer to the allocator that you haven't previously allocated.
These restrictions exist because an allocator implementation is allowed to allocate non-zero amounts of memory for a zero-sized allocation. For example, `malloc` in libc does this.
Currently, ZSTs are handled differently in `Box` and `Vec`:
- `Vec` never allocates when `T` is a ZST or if the vector capacity is 0.
- `Box` just blindly passes everything on to the allocator, including ZSTs.
This causes problems due to the free conversions between `Box<[T]>` and `Vec<T>`, specifically that ZST allocations could get leaked or a dangling pointer could be passed to `deallocate`.
This PR fixes this by changing `Box` to not allocate for zero-sized values and slices. It also fixes a bug in `RawVec::shrink` where shrinking to a size of zero did not actually free the backing memory.
Revert "alloc: Allow comparing Boxs over different allocators", add regression test
Temporary fix for #113283
Adds a test to fix the regression introduced in 001b081cc1 and revert that commit. The test fails without the revert.
This reverts commit 001b081cc1.
This change was done as the above commit introduces a regression in type
inference. Regression test located at
`tests/ui/type-inference/issue-113283-alllocator-trait-eq.rs`
Allow comparing `Box`es with different allocators
Currently, comparing `Box`es over different allocators is not allowed:
```Rust
error[E0308]: mismatched types
--> library/alloc/tests/boxed.rs:22:20
|
22 | assert_eq!(b1, b2);
| ^^ expected `Box<{integer}, ConstAllocator>`, found `Box<{integer}, AnotherAllocator>`
|
= note: expected struct `Box<{integer}, ConstAllocator>`
found struct `Box<{integer}, AnotherAllocator>`
For more information about this error, try `rustc --explain E0308`.
error: could not compile `alloc` (test "collectionstests") due to previous error
```
This PR lifts this limitation
remove unused field
Followup to #104455. The field is no longer needed since ExtractIf (previously DrainFilter) doesn't keep draining in its drop impl.
Implement PartialOrd for `Vec`s over different allocators
It is already possible to `PartialEq` `Vec`s with different allocators, but that is not the case with `PartialOrd`.
This is an `Rc` that is guaranteed to only have one strong reference.
Because it is uniquely owned, it can safely implement `DerefMut`, which
allows programs to have an initialization phase where structures inside
the `Rc` can be mutated.
The `UniqueRc` can then be converted to a regular `Rc`, allowing sharing
and but read-only access.
During the "initialization phase," weak references can be created, but
attempting to upgrade these will fail until the `UniqueRc` has been
converted to a regular `Rc`. This feature can be useful to create
cyclic data structures.
This API is an implementation based on the feedback provided to the ACP
at https://github.com/rust-lang/libs-team/issues/90.
Remove `box_free` lang item
This PR removes the `box_free` lang item, replacing it with `Box`'s `Drop` impl. Box dropping is still slightly magic because the contained value is still dropped by the compiler.
Stabilize String::leak
Stabilizes the following API:
```Rust
impl String {
pub fn leak(self) -> &'static mut str;
}
```
closes#102929
blocked by having an FCP for stabilization.
Ignore `core`, `alloc` and `test` tests that require unwinding on `-C panic=abort`
Some of the tests for `core` and `alloc` require unwinding through their use of `catch_unwind`. These tests fail when testing using `-C panic=abort` (in my case through a target without unwinding support, and `-Z panic-abort-tests`), while they should be ignored as they don't indicate a failure.
This PR marks all of these tests with this attribute:
```rust
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
```
I'm not aware of a way to test this on rust-lang/rust's CI, as we don't test any target with `-C panic=abort`, but I tested this locally on a Ferrocene target and it does indeed make the test suite pass.
Uplift `clippy::invalid_utf8_in_unchecked` lint
This PR aims at uplifting the `clippy::invalid_utf8_in_unchecked` lint into two lints.
## `invalid_from_utf8_unchecked`
(deny-by-default)
The `invalid_from_utf8_unchecked` lint checks for calls to `std::str::from_utf8_unchecked` and `std::str::from_utf8_unchecked_mut` with an invalid UTF-8 literal.
### Example
```rust
unsafe {
std::str::from_utf8_unchecked(b"cl\x82ippy");
}
```
### Explanation
Creating such a `str` would result in undefined behavior as per documentation for `std::str::from_utf8_unchecked` and `std::str::from_utf8_unchecked_mut`.
## `invalid_from_utf8`
(warn-by-default)
The `invalid_from_utf8` lint checks for calls to `std::str::from_utf8` and `std::str::from_utf8_mut` with an invalid UTF-8 literal.
### Example
```rust
std::str::from_utf8(b"ru\x82st");
```
### Explanation
Trying to create such a `str` would always return an error as per documentation for `std::str::from_utf8` and `std::str::from_utf8_mut`.
-----
Mostly followed the instructions for uplifting a clippy lint described here: https://github.com/rust-lang/rust/pull/99696#pullrequestreview-1134072751
````@rustbot```` label: +I-lang-nominated
r? compiler
-----
For Clippy:
changelog: Moves: Uplifted `clippy::invalid_utf8_in_unchecked` into rustc
Support #[global_allocator] without the allocator shim
This makes it possible to use liballoc/libstd in combination with `--emit obj` if you use `#[global_allocator]`. This is what rust-for-linux uses right now and systemd may use in the future. Currently they have to depend on the exact implementation of the allocator shim to create one themself as `--emit obj` doesn't create an allocator shim.
Note that currently the allocator shim also defines the oom error handler, which is normally required too. Once `#![feature(default_alloc_error_handler)]` becomes the only option, this can be avoided. In addition when using only fallible allocator methods and either `--cfg no_global_oom_handling` for liballoc (like rust-for-linux) or `--gc-sections` no references to the oom error handler will exist.
To avoid this feature being insta-stable, you will have to define `__rust_no_alloc_shim_is_unstable` to avoid linker errors.
(Labeling this with both T-compiler and T-lang as it originally involved both an implementation detail and had an insta-stable user facing change. As noted above, the `__rust_no_alloc_shim_is_unstable` symbol requirement should prevent unintended dependence on this unstable feature.)
