remove allow(incomplete_features) from std
cc https://github.com/rust-lang/rust/pull/80349#issuecomment-753357123
> Now I am somewhat concerned that the standard library uses some of these features...
I think it is theoretically ok to use incomplete features in the standard library or the compiler if we know that there is an already working subset and we explicitly document what we have to be careful about. Though at that point it is probably better to try and split the incomplete feature into two separate ones, similar to `min_specialization`.
Will be interesting once `feature(const_evaluatable_checked)` works well enough to imo be used in the compiler but not yet well enough to be removed from `INCOMPLETE_FEATURES`.
r? `@RalfJung`
Add docs note about `Any::type_id` on smart pointers
Fixes#79868.
There's an issue I've run into a couple times while using values of type `Box<dyn Any>` - essentially, calling `value.type_id()` doesn't dereference to the trait object, but uses the implementation of `Any` for `Box<dyn Any>`, giving us the `TypeId` of the container instead of the object inside it.
I couldn't find any notes about this in the documentation and - while it could be inferred from existing knowledge of Rust and the blanket implemenation of `Any` - I think it'd be nice to have a note about it in the documentation for the `any` module.
Anyways, here's a first draft of a section about it. I'm happy to revise wording :)
Remove many unnecessary manual link resolves from library
Now that #76934 has merged, we can remove a lot of these! E.g, this is
no longer necessary:
[`Vec<T>`]: Vec
cc `@jyn514`
The return of the GroupBy and GroupByMut iterators on slice
According to https://github.com/rust-lang/rfcs/pull/2477#issuecomment-742034372, I am opening this PR again, this time I implemented it in safe Rust only, it is therefore much easier to read and is completely safe.
This PR proposes to add two new methods to the slice, the `group_by` and `group_by_mut`. These two methods provide a way to iterate over non-overlapping sub-slices of a base slice that are separated by the predicate given by the user (e.g. `Partial::eq`, `|a, b| a.abs() < b.abs()`).
```rust
let slice = &[1, 1, 1, 3, 3, 2, 2, 2];
let mut iter = slice.group_by(|a, b| a == b);
assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
assert_eq!(iter.next(), Some(&[3, 3][..]));
assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
assert_eq!(iter.next(), None);
```
[An RFC](https://github.com/rust-lang/rfcs/pull/2477) was open 2 years ago but wasn't necessary.
Remove all doc_comment!{} hacks by using #[doc = expr] where needed.
This replaces about 200 cases of
`````rust
doc_comment! {
concat!("The smallest value that can be represented by this integer type.
# Examples
Basic usage:
```
", $Feature, "assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");",
$EndFeature, "
```"),
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MIN: Self = !0 ^ ((!0 as $UnsignedT) >> 1) as Self;
}
`````
by
```rust
/// The smallest value that can be represented by this integer type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MIN: Self = !0 ^ ((!0 as $UnsignedT) >> 1) as Self;
```
---
**Note:** For a usable diff, make sure to enable 'ignore whitspace': https://github.com/rust-lang/rust/pull/79150/files?diff=unified&w=1
Rollup of 9 pull requests
Successful merges:
- #78934 (refactor: removing library/alloc/src/vec/mod.rs ignore-tidy-filelength)
- #79479 (Add `Iterator::intersperse`)
- #80128 (Edit rustc_ast::ast::FieldPat docs)
- #80424 (Don't give an error when creating a file for the first time)
- #80458 (Some Promotion Refactoring)
- #80488 (Do not create dangling &T in Weak<T>::drop)
- #80491 (Miri: make size/align_of_val work for dangling raw ptrs)
- #80495 (Rename kw::Invalid -> kw::Empty)
- #80513 (Add regression test for #80062)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Do not create dangling &T in Weak<T>::drop
Since at this point all strong pointers have been dropped, the wrapped `T` has also been dropped. As such, creating a `&T` to the dropped place is negligent at best (language UB at worst). Since we have `Layout::for_value_raw` now, use that instead of `Layout::for_value` to avoid creating the `&T`.
This does have implications for custom (potentially thin) DSTs, though much less severe than those discussed in #80407. Specifically, one of two things has to be true:
- It has to be possible to use a `*const T` to a dropped (potentially custom, potentially thin) unsized tailed object to determine the layout (size/align) of the object. This is what is currently implemented (though with `&T` instead of `&T`). The validity of reading some location after it has been dropped is an open question IIUC (https://github.com/rust-lang/unsafe-code-guidelines/issues/188) (except when the whole type is `Copy`, per `drop_in_place`'s docs).
In this design, custom DSTs would get a `*mut T` and use that to return layout, and must be able to do so while in the "zombie" (post-drop, pre-free) state.
- `RcBox`/`ArcInner` compute and store layout eagerly, so that they don't have to ask the type for its layout after dropping it.
Importantly, this is already true today, as you can construct `Rc<DST>`, create a `Weak<DST>`, and drop the `Rc` before the `Weak`. This PR is a strict improvement over the status quo, and the above question about potentially thin DSTs will need to be resolved by any custom DST proposal.
refactor: removing library/alloc/src/vec/mod.rs ignore-tidy-filelength
This PR removes the need for ignore-tidy-filelength for library/alloc/src/vec/mod.rs which is part of the issue #60302
It is probably easiest to review this PR by looking at it commit by commit rather than looking at the overall diff.
Rollup of 7 pull requests
Successful merges:
- #80185 (Fix ICE when pointing at multi bytes character)
- #80260 (slightly more typed interface to panic implementation)
- #80311 (Improvements to NatVis support)
- #80337 (Use `desc` as a doc-comment for queries if there are no doc comments)
- #80381 (Revert "Cleanup markdown span handling")
- #80492 (remove empty wraps, don't return Results from from infallible functions)
- #80509 (where possible, pass slices instead of &Vec or &String (clippy::ptr_arg))
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
slightly more typed interface to panic implementation
The panic payload is currently being passed around as a `usize`. However, it actually is a pointer, and the involved types are available on all ends of this API, so I propose we use the proper pointer type to avoid some casts. Avoiding int-to-ptr casts also makes this code work with `miri -Zmiri-track-raw-pointers`.
