BTreeMap: refactor Entry out of map.rs into its own file
btree/map.rs is approaching the 3000 line mark, splitting out the entry
code buys about 500 lines of headroom.
I've created this PR because the changes I've made in #77438 will push `map.rs` over the 3000 line limit and cause tidy to complain.
I picked `Entry` to factor out because it feels less tightly coupled to the rest of `BTreeMap` than the various iterator implementations.
Related: #60302
BTreeMap: improve gdb introspection of BTreeMap with ZST keys or values
I accidentally pushed an earlier revision in #77788: it changes the index of tuples for BTreeSet from ""[{}]".format(i) to "key{}".format(i). Which doesn't seem to make the slightest difference on my linux box nor on CI. In fact, gdb doesn't make any distinction between "key{}" and "val{}" for a BTreeMap either, leading to confusing output if you test more. But easy to improve.
r? @Mark-Simulacrum
liballoc: VecDeque: Add binary search functions
I am submitting rust-lang/rfcs#2997 as a PR as suggested by @scottmcm
I haven't yet created a tracking issue - if there's a favorable feedback I'll create one and update the issue links in the unstable attribs.
Remove shrink_to_fit from default ToString::to_string implementation.
As suggested by `@scottmcm` on Zulip. shrink_to_fit() seems like the wrong thing to do here in most use cases of to_string(). Would be intereseting to see if it makes any difference in a timer run.
r? `@joshtriplett`
fix __rust_alloc_error_handler comment
`__rust_alloc_error_handler` was added in the same `extern` block as the allocator functions, but the comment there was not actually correct for `__rust_alloc_error_handler`. So move it down to the rest of the default allocator handling with a fixed comment. At least the comment reflects my understanding of what happens, please check carefully. :)
r? @Amanieu Cc @haraldh
BTreeMap: comment why drain_filter's size_hint is somewhat pessimistic
The `size_hint` of the `DrainFilter` iterator doesn't adjust as you iterate. This hardly seems important to me, but there has been a comparable PR #64383 in the past. I guess a scenario is that you first iterate half the map manually and keep most of the key/value pairs in the map, and then tell the predicate to drain most of the key/value pairs and `.collect` the iterator over the remaining half of the map.
I am totally ambivalent whether this is better or not.
r? @Mark-Simulacrum
Add PartialEq impls for Vec <-> slice
This is a follow-up to #71660 and rust-lang/rfcs#2917 to add two more missing vec/slice PartialEq impls:
```
impl<A, B> PartialEq<[B]> for Vec<A> where A: PartialEq<B> { .. }
impl<A, B> PartialEq<Vec<B>> for [A] where A: PartialEq<B> { .. }
```
Since this is insta-stable, it should go through the `@rust-lang/libs` FCP process. Note that I used version 1.47.0 for the `stable` attribute because I assume this will not merge before the 1.46.0 branch is cut next week.
Remove `Box::leak_with_alloc`
Add leak-test for box with allocator
Rename `AllocErr` to `AllocError` in leak-test
Add `Box::alloc` and adjust examples to use the new API
Replace some once(x).chain(once(y)) with [x, y] IntoIter
Now that we have by-value array iterators that are [already used](25c8c53dd9/compiler/rustc_hir/src/def.rs (L305-L307))...
For example,
```diff
- once(self.type_ns).chain(once(self.value_ns)).chain(once(self.macro_ns)).filter_map(|it| it)
+ IntoIter::new([self.type_ns, self.value_ns, self.macro_ns]).filter_map(|it| it)
```
BTreeMap: admit the existence of leaf edges in comments
The btree code is ambiguous about leaf edges (i.e., edges within leaf nodes). Iteration relies on them heavily, but some of the comments suggest there are no leaf edges (extracted from #77025)
r? @Mark-Simulacrum
BTreeMap: complete the compile-time test_variance test case
Some of the items added to the new `test_sync` belonged in the old `test_variance` as well. And fixed inconsistent paths to nearby modules.
r? @Mark-Simulacrum
Implement Make `handle_alloc_error` default to panic (for no_std + liballoc)
Related: https://github.com/rust-lang/rust/issues/66741
Guarded with `#![feature(default_alloc_error_handler)]` a default
`alloc_error_handler` is called, if a custom allocator is used and no
other custom `#[alloc_error_handler]` is defined.
