Don't import integer and float modules, use assoc consts
Stop importing the standard library integer and float modules to reach the `MIN`, `MAX` and other constants. They are available directly on the primitive types now.
This PR is a follow up of #69860 which made sure we use the new constants in documentation.
This type of change touches a lot of files, and previously all my assoc int consts PRs had collisions and were accepted only after a long delay. So I'd prefer to do it in smaller steps now. Just removing these imports seem like a good next step.
r? @dtolnay
Fix some aliasing issues in Vec
`Vec::extend` and `Vec::truncate` invalidated references into the vector even without reallocation, because they (implicitly) created a mutable reference covering the *entire* initialized part of the vector.
Fixes https://github.com/rust-lang/rust/issues/70301
I verified the fix by adding some new tests here that I ran in Miri.
Overhaul of the `AllocRef` trait to match allocator-wg's latest consens; Take 2
GitHub won't let me reopen#69889 so I make a new PR.
In addition to #69889 this fixes the unsoundness of `RawVec::into_box` when using allocators supporting overallocating. Also it uses `MemoryBlock` in `AllocRef` to unify `_in_place` methods by passing `&mut MemoryBlock`. Additionally, `RawVec` now checks for `size_of::<T>()` again and ignore every ZST. The internal capacity of `RawVec` isn't used by ZSTs anymore, as `into_box` now requires a length to be specified.
r? @Amanieu
fixesrust-lang/wg-allocators#38fixesrust-lang/wg-allocators#41fixesrust-lang/wg-allocators#44fixesrust-lang/wg-allocators#51
BTreeMap/BTreeSet: implement drain_filter
Provide an implementation of drain_filter for BTreeMap and BTreeSet. Should be optimal when the predicate picks only elements in leaf nodes with at least MIN_LEN remaining elements, which is a common case, at least when draining only a fraction of the map/set, and also when the predicate picks elements stored in internal nodes where the right subtree can easily let go of a replacement element.
The first commit adds benchmarks with an external, naive implementation. to compare how much this claimed optimality-in-some-cases is actually worth.
Remove `usable_size` APIs
This removes the usable size APIs:
- remove `usable_size` (obv)
- change return type of allocating methods to include the allocated size
- remove `_excess` API
r? @Amanieu
closesrust-lang/wg-allocators#17
Audit liballoc for leaks in `Drop` impls when user destructor panics
Inspired by https://github.com/rust-lang/rust/pull/67243 and https://github.com/rust-lang/rust/pull/67235, this audits and hopefully fixes the remaining `Drop` impls in liballoc for resource leaks in the presence of panics in destructors called by the affected `Drop` impl.
This does not touch `Hash{Map,Set}` since they live in hashbrown. They have similar issues though.
r? @KodrAus
Implement split_inclusive for slice and str
# Overview
* Implement `split_inclusive` for `slice` and `str` and `split_inclusive_mut` for `slice`
* `split_inclusive` is a substring/subslice splitting iterator that includes the matched part in the iterated substrings as a terminator.
* EDIT: The behaviour has now changed, as per @KodrAus 's input, to the same semantics with the `split_terminator` function. I updated the examples below.
* Two examples below:
```Rust
let data = "\nMäry häd ä little lämb\nLittle lämb\n";
let split: Vec<&str> = data.split_inclusive('\n').collect();
assert_eq!(split, ["\n", "Märy häd ä little lämb\n", "Little lämb\n"]);
```
```Rust
let uppercase_separated = "SheePSharKTurtlECaT";
let mut first_char = true;
let split: Vec<&str> = uppercase_separated.split_inclusive(|c: char| {
let split = !first_char && c.is_uppercase();
first_char = split;
split
}).collect();
assert_eq!(split, ["SheeP", "SharK", "TurtlE", "CaT"]);
```
# Justification for the API
* I was surprised to find that stdlib currently only has splitting iterators that leave out the matched part. In my experience, wanting to leave a substring terminator as a part of the substring is a pretty common usecase.
* This API is strictly more expressive than the standard `split` API: it's easy to get the behaviour of `split` by mapping a subslicing operation that drops the terminator. On the other hand it's impossible to derive this behaviour from `split` without using hacky and brittle `unsafe` code. The normal way to achieve this functionality would be implementing the iterator yourself.
* Especially when dealing with mutable slices, the only way currently is to use `split_at_mut`. This API provides an ergonomic alternative that plays to the strengths of the iterating capabilities of Rust. (Using `split_at_mut` iteratively used to be a real pain before NLL, fortunately the situation is a bit better now.)
# Discussion items
* <s>Does it make sense to mimic `split_terminator` in that the final empty slice would be left off in case of the string/slice ending with a terminator? It might do, as this use case is naturally geared towards considering the matching part as a terminator instead of a separator.</s>
* EDIT: The behaviour was changed to mimic `split_terminator`.
* Does it make sense to have `split_inclusive_mut` for `&mut str`?
Derive Clone + Eq for std::string::FromUtf8Error
Implement `Clone` and `Eq` for `std::string::FromUtf8Error`.
Both the inner `Vec<u8>` and `std::str::Utf8Error` are also `Clone + Eq`, so I don't see why we shouldn't derive them on `FromUtf8Error` as well.
(impl are insta-stable, requiring FCP from T-libs.)
Implement clone_from for BTreeMap and BTreeSet
See #28481. This results in up to 90% speedups on simple data types when `self` and `other` are the same size, and is generally comparable or faster. Some concerns:
1. This implementation requires an `Ord` bound on the `Clone` implementation for `BTreeMap` and `BTreeSet`. Since these structs can only be created externally for keys with `Ord` implemented, this should be fine? If not, there's certainly a less safe way to do this.
2. Changing `next_unchecked` on `RangeMut` to return mutable key references allows for replacing the entire overlapping portion of both maps without changing the external interface in any way. However, if `clone_from` fails it can leave the `BTreeMap` in an invalid state, which might be unacceptable.
~This probably needs an FCP since it changes a trait bound, but (as far as I know?) that change cannot break any external code.~
