Dont segfault if btree range is not in order
This is a first attempt to fix issue #33197. The issue is that the BTree iterator uses next_unchecked for fast iteration, but it can be tricked into running off the end of the tree and segfaulting if range is called with a maximum that is less than the minimum.
Since a user defined Ord should not determine the safety of BTreeMap, and we still want fast iteration, I've implemented the idea of @gereeter and walk the tree simultaneously searching for both keys to make sure that if our keys diverge, the min key is to the left of our max key. I currently panic if that is not the case.
Open questions:
1. Do we want to panic in this error case or do we want to return an empty iterator? The drain API panics if the range is bad, but drain is given a range of index values, while this is a generic key type. Panicking is brittle and returning an empty iterator is probably the most flexible and matches what people would want it to do... but artificially returning a BTreeMap::Range with start==end seems like a pretty weird and unnatural thing to do, although it's doable since those fields are not accessible.
The same question for other weird cases:
2. (Included(101), Excluded(100)) on a map that contains [1,2,3]. Both BTree edges end up on the same part of the map, but comparing the keys shows the range is backwards.
3. (Excluded(5), Excluded(5)). The keys are equal but BTree edges end up backwards if the map contains 5.
4. (Included(5), Excluded(5)). Should naturally produce an empty iterator, right?
Explicitly mention that `Vec::reserve` is based on len not capacity
I spent a good chunk of time tracking down a buffer overrun bug that
resulted from me mistakenly thinking that `reserve` was based on the
current capacity not the current length. It would be helpful if this
were called out explicitly in the docs.
I spent a good chunk of time tracking down a buffer overrun bug that
resulted from me mistakenly thinking that `reserve` was based on the
current capacity not the current length. It would be helpful if this
were called out explicitly in the docs.
std: Add ToString trait specialization for Cow<'a, str> and String
There is a specialized version of ToString for str type in std. I think there are other types can also benefit from specialization. `Cow` and `String` are the most obvious one.
r? @bluss
Rewrite the first sentence in slice::sort
For every method, the first sentence should consisely explain what it does,
not how. This sentence usually starts with a verb.
It's really weird for `sort` to be explained in terms of another function,
namely `sort_by`. There's no need for that because it's obvious how `sort`
sorts elements: there is `T: Ord`.
If `sort_by_key` does not have to explicitly state how it's implemented,
then `sort` doesn't either.
r? @steveklabnik
std: Stabilize APIs for the 1.16.0 release
This commit applies the stabilization/deprecations of the 1.16.0 release, as
tracked by the rust-lang/rust issue tracker and the final-comment-period tag.
The following APIs were stabilized:
* `VecDeque::truncate`
* `VecDeque::resize`
* `String::insert_str`
* `Duration::checked_{add,sub,div,mul}`
* `str::replacen`
* `SocketAddr::is_ipv{4,6}`
* `IpAddr::is_ipv{4,6}`
* `str::repeat`
* `Vec::dedup_by`
* `Vec::dedup_by_key`
* `Result::unwrap_or_default`
* `<*const T>::wrapping_offset`
* `<*mut T>::wrapping_offset`
* `CommandExt::creation_flags` (on Windows)
* `File::set_permissions`
* `String::split_off`
The following APIs were deprecated
* `EnumSet` - replaced with other ecosystem abstractions, long since unstable
Closes#27788Closes#35553Closes#35774Closes#36436Closes#36949Closes#37079Closes#37087Closes#37516Closes#37827Closes#37916Closes#37966Closes#38080
For every method, the first sentence should consisely explain what it does,
not how. This sentence usually starts with a verb.
It's really weird for `sort` to be explained in terms of another function,
namely `sort_by`. There's no need for that because it's obvious how `sort`
sorts elements: there is `T: Ord`.
If `sort_by_key` does not have to explicitly state how it's implemented,
then `sort` doesn't either.
This commit applies the stabilization/deprecations of the 1.16.0 release, as
tracked by the rust-lang/rust issue tracker and the final-comment-period tag.
The following APIs were stabilized:
* `VecDeque::truncate`
* `VecDeque::resize`
* `String::insert_str`
* `Duration::checked_{add,sub,div,mul}`
* `str::replacen`
* `SocketAddr::is_ipv{4,6}`
* `IpAddr::is_ipv{4,6}`
* `str::repeat`
* `Vec::dedup_by`
* `Vec::dedup_by_key`
* `Result::unwrap_or_default`
* `<*const T>::wrapping_offset`
* `<*mut T>::wrapping_offset`
* `CommandExt::creation_flags` (on Windows)
* `File::set_permissions`
* `String::split_off`
The following APIs were deprecated
* `EnumSet` - replaced with other ecosystem abstractions, long since unstable
Closes#27788Closes#35553Closes#35774Closes#36436Closes#36949Closes#37079Closes#37087Closes#37516Closes#37827Closes#37916Closes#37966Closes#38080
Clarify when range is removed by drain
Based on a discussion on #rust-beginners the existing note for drain is confusing. This new wording was suggested.
Implement placement-in protocol for `BinaryHeap`
Related to #30172, and loosley based on #38551.
At the moment, this PR is in a pretty rough state, but I wanted to get some feedback to see if I'm going in the right direction.
I hope the Mentor label of #30172 is still applicable, even though it's a year old 😄
A few improvements to the slice docs.
* Simplify `Option::iter_mut` doc example.
* Document 'empty' corner-cases for `slice::{starts_with, ends_with}`.
* Indicate 'true' as code-like.
