Simplify Clone for Box<[T]>
The bespoke `BoxBuilder` was basically a very simple `Vec`. Instead,
let's clone to a real `Vec`, with all of its specialization for the
task, then convert back to `Box<[T]>`.
prune ill-conceived BTreeMap iter_mut assertion and test its mutability
Proposal to deal with #67438 (and I'm more sure now that this is the right thing to do).
Passes testing with miri.
Remove redundant link texts
Most of these links are followed by a parenthesized expression. I think that the redundant link texts were added to prevent interpretation as an inline link. This is unnecessary since the closing square bracket and opening parenthesis are separated by whitespace.
The bespoke `BoxBuilder` was basically a very simple `Vec`. Instead,
let's clone to a real `Vec`, with all of its specialization for the
task, then convert back to `Box<[T]>`.
Stabilize `std::{rc,sync}::Weak::{weak_count, strong_count}`
* Original PR: #56696
* Tracking issue: #57977Closes: #57977
Supporting comments:
> Although these were added for testing, it is occasionally useful to have a way to probe optimistically for whether a weak pointer has become dangling, without actually taking the overhead of manipulating atomics. Are there any plans to stabilize this?
_Originally posted by @bdonlan in https://github.com/rust-lang/rust/issues/57977#issuecomment-516970921_
> Having this stabilized would help. Currently, the only way to check if a weak pointer has become dangling is to call `upgrade`, which is by far expensive.
_Originally posted by @glebpom in https://github.com/rust-lang/rust/issues/57977#issuecomment-526934709_
Not sure if stabilizing these warrants a full RFC, so throwing this out here as a start for now.
Note: per CONTRIBUTING.md, I ran the tidy checks, but they seem to be failing on unchanged files (primarily in `src/stdsimd`).
Restore original implementation of Vec::retain
This PR reverts #48065, which aimed to optimize `Vec::retain` by making use of `Vec::drain_filter`. Unfortunately at that time, `drain_filter` was unsound.
The soundness hole in `Vec::drain_filter` was fixed in #61224 by guaranteeing that cleanup logic runs via a nested `Drop`, even in the event of a panic. Implementing this nested drop affects codegen (apparently?) and results in slower code.
Fixes#65970
This PR reverts #48065, which aimed to optimize `Vec::retain` by
making use of `Vec::drain_filter`. Unfortunately at that time,
`drain_filter` was unsound.
The soundness hole in `Vec::drain_filter` was fixed in #61224 by
guaranteeing that cleanup logic runs via a nested `Drop`, even in
the event of a panic. Implementing this nested drop affects codegen
(apparently?) and results in slower code.
Fixes#65970
Require stable/unstable annotations for the constness of all stable fns with a const modifier
r? @RalfJung @Centril
Every `#[stable]` const fn now needs either a `#[rustc_const_unstable]` attribute or a `#[rustc_const_stable]` attribute. You can't silently stabilize the constness of a function anymore.
LinkedList: drop remaining items when drop panics
https://github.com/rust-lang/rust/pull/67235, but for `LinkedList`, which has the same issue.
I've also copied over the other drop-related tests from `VecDeque` since AFAICT `LinkedList` didn't have any.
Match `VecDeque::extend` to `Vec::extend_desugared`
Currently, `VecDeque::extend` [does not reserve at all](https://github.com/rust-lang/rust/pull/65069#discussion_r333166522). This implementation still runs a check every iteration of the loop, but should reallocate at most once for the common cases where the `size_hint` lower bound is exact. Further optimizations in the future could improve this for some common cases, but given the complexity of the `Vec::extend` implementation it's not immediately clear that this would be worthwhile.
Stein Somers