`std::vec`: Add UB check for `set_len`, `from_raw_parts_in`, and etc.
Closesrust-lang/rust#143813
I noticed that `from_parts_in` do the similar things like `from_raw_parts_in`, so I add the UB check in the last commit. If it is not appropriate, I will remove it.
And I fix a typo in the first commit.
r? `@scottmcm`
Rollup of 11 pull requests
Successful merges:
- rust-lang/rust#131923 (Derive `Copy` and `Hash` for `IntErrorKind`)
- rust-lang/rust#138340 (Remove some unsized tuple impls now that we don't support unsizing tuples anymore)
- rust-lang/rust#141219 (Change `{Box,Arc,Rc,Weak}::into_raw` to only work with `A = Global`)
- rust-lang/rust#142212 (bootstrap: validate `rust.codegen-backends` & `target.<triple>.codegen-backends`)
- rust-lang/rust#142237 (Detect more cases of unused_parens around types)
- rust-lang/rust#142964 (Attribute rework: a parser for single attributes without arguments)
- rust-lang/rust#143070 (Rewrite `macro_rules!` parser to not use the MBE engine itself)
- rust-lang/rust#143235 (Assemble const bounds via normal item bounds in old solver too)
- rust-lang/rust#143261 (Feed `explicit_predicates_of` instead of `predicates_of`)
- rust-lang/rust#143276 (loop match: handle opaque patterns)
- rust-lang/rust#143306 (Add `track_caller` attributes to trace origin of Clippy lints)
r? `@ghost`
`@rustbot` modify labels: rollup
try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: x86_64-gnu
try-job: dist-i586-gnu-i586-i686-musl
try-job: test-various
Also applies to `Vec::into_raw_parts`.
The expectation is that you can round-trip these methods with
`from_raw`, but this is only true when using the global allocator. With
custom allocators you should instead be using
`into_raw_with_allocator` and `from_raw_in`.
The implementation of `Box::leak` is changed to use
`Box::into_raw_with_allocator` and explicitly leak the allocator (which
was already the existing behavior). This is because, for `leak` to be
safe, the allocator must not free its underlying backing store. The
`Allocator` trait only guarantees that allocated memory remains valid
until the allocator is dropped.
Take the one from `BTreeMap` that seems the best-worded and most
precise among the available variations.
Signed-off-by: Paul Mabileau <paul.mabileau@harfanglab.fr>
Consistent trait bounds for ExtractIf Debug impls
Closes#137654. Refer to that issue for a table of the **4** different impl signatures we previously had in the standard library for Debug impls of various ExtractIf iterator types.
The one we are standardizing on is the one so far only used by `alloc::collections::linked_list::ExtractIf`, which is _no_ `F: Debug` bound, _no_ `F: FnMut` bound, only `T: Debug` bound.
This PR applies the following signature changes:
```diff
/* alloc::collections::btree_map */
pub struct ExtractIf<'a, K, V, F, A = Global>
where
- F: 'a + FnMut(&K, &mut V) -> bool,
Allocator + Clone,
impl Debug for ExtractIf<'a, K, V, F,
+ A,
>
where
K: Debug,
V: Debug,
- F: FnMut(&K, &mut V) -> bool,
+ A: Allocator + Clone,
```
```diff
/* alloc::collections::btree_set */
pub struct ExtractIf<'a, T, F, A = Global>
where
- T: 'a,
- F: 'a + FnMut(&T) -> bool,
Allocator + Clone,
impl Debug for ExtractIf<'a, T, F, A>
where
T: Debug,
- F: FnMut(&T) -> bool,
A: Allocator + Clone,
```
```diff
/* alloc::collections::linked_list */
impl Debug for ExtractIf<'a, T, F,
+ A,
>
where
T: Debug,
+ A: Allocator,
```
```diff
/* alloc::vec */
impl Debug for ExtractIf<'a, T, F, A>
where
T: Debug,
- F: Debug,
A: Allocator,
- A: Debug,
```
```diff
/* std::collections::hash_map */
pub struct ExtractIf<'a, K, V, F>
where
- F: FnMut(&K, &mut V) -> bool,
impl Debug for ExtractIf<'a, K, V, F>
where
+ K: Debug,
+ V: Debug,
- F: FnMut(&K, &mut V) -> bool,
```
```diff
/* std::collections::hash_set */
pub struct ExtractIf<'a, T, F>
where
- F: FnMut(&T) -> bool,
impl Debug for ExtractIf<'a, T, F>
where
+ T: Debug,
- F: FnMut(&T) -> bool,
```
I have made the following changes to bring these types into better alignment with one another.
- Delete `F: Debug` bounds. These are especially problematic because Rust closures do not come with a Debug impl, rendering the impl useless.
- Delete `A: Debug` bounds. Allocator parameters are unstable for now, but in the future this would become an API commitment that we do not debug-print a representation of the allocator when printing an iterator.
- Delete `F: FnMut` bounds. Requires `hashbrown` PR: https://github.com/rust-lang/hashbrown/pull/616. **API commitment:** we commit to not doing RefCell voodoo inside ExtractIf to have some way for its Debug impl (which takes &self) to call a FnMut closure, if this is even possible.
- Add `T: Debug` bounds (or `K`/`V`), even on Debug impls that do not currently make use of them, but might in the future. **Breaking change.** Must backport into Rust 1.87 (current beta) or do a de-stabilization PR in beta to delay those types by one release.
- Render using `debug_struct` + `finish_non_exhaustive`, instead of `debug_tuple`.
- Do not render the _entire_ underlying collection.
- Show a "peek" field indicating the current position of the iterator.
Correct `extract_if` sample equivalent.
Tracking issue: https://github.com/rust-lang/rust/issues/43244
Original PR: #133265
The sample code marked as equivalent in the doc comment isn't currently equivalent. Given the same predicate and range, if your vector were `[1, 2, 3, 3, 3, 3, 3, 3, 4, 5, 6]`, then all of the 3s would be removed. `i` is only incremented when an element is dropped, but `range.end` is unchanged, so the items shift down. I got very confused when reading the docs and trying to square this sample code with the explanation of how the function works.
Fortunately, the real `extract_if()` does not have this problem. I've added an `end` variable to align the behavior. I've also taken the opportunity to simplify the predicate, which now just matches odd numbers, and to pad out the vec of numbers to line up the zero-indexed range with the integers in the vec.
r? the8472
document capacity for ZST as example
The main text already covers this, although it provides weaker guarantees, but I think an example in the right spot does not hurt. Fixes#80747
Use `std::mem::{size_of, size_of_val, align_of, align_of_val}` from the
prelude instead of importing or qualifying them.
These functions were added to all preludes in Rust 1.80.
