Cosmetic improvements to doc comments
This has been factored out from https://github.com/rust-lang/rust/pull/58036 to only include changes to documentation comments (throughout the rustc codebase).
r? @steveklabnik
Once you're happy with this, maybe we could get it through with r=1, so it doesn't constantly get invalidated? (I'm not sure this will be an issue, but just in case...) Anyway, thanks for your advice so far!
libcore, liballoc: disable tests in Miri
I am going to run the libcore and liballoc unit test suites in Miri. Not all tests pass. This PR disables a whole bunch of tests when running in Miri, to get us to a baseline from which I can investigate failures.
Cc @SimonSapin @alexcrichton
This change updates the future and task API as discussed in the stabilization RFC at https://github.com/rust-lang/rfcs/pull/2592.
Changes:
- Replacing UnsafeWake with RawWaker and RawWakerVtable
- Removal of LocalWaker
- Removal of Arc-based Wake trait
Transition liballoc to Rust 2018
This transitions liballoc to Rust 2018 edition and applies relevant idiom lints.
I also did a small bit of drive-by cleanup along the way.
r? @oli-obk
I started with liballoc since it seemed easiest. In particular, adding `edition = "2018"` to libcore gave me way too many errors due to stdsimd. Ideally we should be able to continue this crate-by-crate until all crates use 2018.
Implement Weak::{strong_count, weak_count}
The counters are also useful on `Weak`, not just on strong references (`Rc` or `Arc`).
In situations where there are still strong references around, you can also get these counts by temporarily upgrading and adjusting the values accordingly. Using the methods introduced here is simpler to do, less error-prone (since you can't forget to adjust the counts), can also be used when no strong references are around anymore, and might be more efficient due to not having to temporarily create an `Rc`.
This is mainly useful in assertions or tests of complex data structures. Data structures might have internal invariants that make them the sole owner of a `Weak` pointer, and an assertion on the weak count could be used to ensure that this indeed happens as expected. Due to the presence of `Weak::upgrade`, the `strong_count` becomes less useful, but it still seems worthwhile to mirror the API of `Rc`.
TODO:
* [X] Tracking issue - https://github.com/rust-lang/rust/issues/57977
Closes https://github.com/rust-lang/rust/issues/50158
Kill remaining uses of mem::uninitialized in libcore, liballoc
Kill remaining uses of mem::uninitialized in libcore and liballoc, and enable a lint that will warn when uses are added again in the future.
To avoid casting raw pointers around (which is always very dangerous because it is not typechecked at all -- it doesn't even get the "same size" sanity check that `transmute` gets), I also added two new functions to `MaybeUninit`:
```rust
/// Get a pointer to the first contained values.
pub fn first_ptr(this: &[MaybeUninit<T>]) -> *const T {
this as *const [MaybeUninit<T>] as *const T
}
/// Get a mutable pointer to the first contained values.
pub fn first_mut_ptr(this: &mut [MaybeUninit<T>]) -> *mut T {
this as *mut [MaybeUninit<T>] as *mut T
}
```
I changed some of the existing code to use array-of-`MaybeUninit` instead of `MaybeUninit`-of-array, successfully removing raw pointer casts there as well.
