rust/library/std
Matthias Krüger a26b1d2259
Rollup merge of #89835 - jkugelman:must-use-expensive-computations, r=joshtriplett
Add #[must_use] to expensive computations

The unifying theme for this commit is weak, admittedly. I put together a list of "expensive" functions when I originally proposed this whole effort, but nobody's cared about that criterion. Still, it's a decent way to bite off a not-too-big chunk of work.

Given the grab bag nature of this commit, the messages I used vary quite a bit. I'm open to wording changes.

For some reason clippy flagged four `BTreeSet` methods but didn't say boo about equivalent ones on `HashSet`. I stared at them for a while but I can't figure out the difference so I added the `HashSet` ones in.

```rust
// Flagged by clippy.
alloc::collections::btree_set::BTreeSet<T>   fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T>;
alloc::collections::btree_set::BTreeSet<T>   fn symmetric_difference<'a>(&'a self, other: &'a BTreeSet<T>) -> SymmetricDifference<'a, T>
alloc::collections::btree_set::BTreeSet<T>   fn intersection<'a>(&'a self, other: &'a BTreeSet<T>) -> Intersection<'a, T>;
alloc::collections::btree_set::BTreeSet<T>   fn union<'a>(&'a self, other: &'a BTreeSet<T>) -> Union<'a, T>;

// Ignored by clippy, but not by me.
std::collections::HashSet<T, S>              fn difference<'a>(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S>;
std::collections::HashSet<T, S>              fn symmetric_difference<'a>(&'a self, other: &'a HashSet<T, S>) -> SymmetricDifference<'a, T, S>
std::collections::HashSet<T, S>              fn intersection<'a>(&'a self, other: &'a HashSet<T, S>) -> Intersection<'a, T, S>;
std::collections::HashSet<T, S>              fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S>;
```

Parent issue: #89692

r? ```@joshtriplett```
2021-10-31 09:20:24 +01:00
..
benches mv std libs to library/ 2020-07-27 19:51:13 -05:00
primitive_docs Add primitive documentation to libcore 2021-09-12 02:23:08 +00:00
src Rollup merge of #89835 - jkugelman:must-use-expensive-computations, r=joshtriplett 2021-10-31 09:20:24 +01:00
tests Update aarch64 runtime feature detection tests 2021-08-03 12:07:56 +00:00
build.rs Add SOLID targets 2021-09-28 11:31:47 +09:00
Cargo.toml Update libc to 0.2.103. 2021-10-06 14:33:13 +00:00