Add "length" as doc alias to len methods
Currently when searching for `length` there are no results: https://doc.rust-lang.org/std/?search=length. This makes `len` methods appear when searching for `length`.
BTreeMap: clean up access to MaybeUninit arrays
Stop exposing and using immutable access to `MaybeUninit` slices when we need and have exclusive access to the tree.
r? `@Mark-Simulacrum`
BTreeMap: relax the explicit borrow rule to make code shorter and safer
Expressions like `.reborrow_mut().into_len_mut()` are annoyingly long, and kind of dangerous for the reason `reborrow_mut()` is unsafe. By relaxing the single rule, we no longer have to make an exception for functions with a `borrow` name and functions like `as_leaf_mut`. This is largely restoring the declaration style of the btree::node API about a year ago, but with more explanation and consistency.
r? `@Mark-Simulacrum`
Stabilize or_insert_with_key
Stabilizes the `or_insert_with_key` feature from https://github.com/rust-lang/rust/issues/71024. This allows inserting key-derived values when a `HashMap`/`BTreeMap` entry is vacant.
The difference between this and `.or_insert_with(|| ... )` is that this provides a reference to the key to the closure after it is moved with `.entry(key_being_moved)`, avoiding the need to copy or clone the key.
Fix overflow when converting ZST Vec to VecDeque
```rust
let v = vec![(); 100];
let queue = VecDeque::from(v);
println!("{:?}", queue);
```
This code will currently panic with a capacity overflow.
This PR resolves this issue and makes the code run fine.
Resolves#78532
Do not inline finish_grow
Fixes#78471.
Looking at libgkrust.a in Firefox, the sizes for the `gkrust.*.o` file is:
- 18584816 (text) 582418 (data) with unmodified master
- 17937659 (text) 582554 (data) with #72227 reverted
- 17968228 (text) 582858 (data) with `#[inline(never)]` on `grow_amortized` and `grow_exact`, but that has some performance consequences
- 17927760 (text) 582322 (data) with this change
So in terms of size, at least in the case of Firefox, this patch more than undoes the regression. I don't think it should affect performance, but we'll see.
doc(array,vec): add notes about side effects when empty-initializing
Copying some context from a conversation in the Rust discord:
* Both `vec![T; 0]` and `[T; 0]` are syntactically valid, and produce empty containers of their respective types
* Both *also* have side effects:
```rust
fn side_effect() -> String {
println!("side effect!");
"foo".into()
}
fn main() {
println!("before!");
let x = vec![side_effect(); 0];
let y = [side_effect(); 0];
println!("{:?}, {:?}", x, y);
}
```
produces:
```
before!
side effect!
side effect!
[], []
```
This PR just adds two small notes to each's documentation, warning users that side effects can occur.
I've also submitted a clippy proposal: https://github.com/rust-lang/rust-clippy/issues/6439
BTreeMap: clarify comments and panics around choose_parent_kv
Fixes a lie in recent code: `unreachable!("empty non-root node")` should shout "empty internal node", but it might as well be good and keep quiet
r? `@Mark-Simulacrum`
