Add #[must_use] to expensive computations #89835

jkugelman · 2021-10-12T23:28:03Z

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.

// 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

library/alloc/src/collections/btree/set.rs

library/alloc/src/string.rs

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.

joshtriplett · 2021-10-30T22:35:01Z

@bors r+

bors · 2021-10-30T22:35:02Z

📌 Commit 21f4677 has been approved by joshtriplett

…ations, 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: rust-lang#89692 r? `@joshtriplett`

…ations, 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: rust-lang#89692 r? ``@joshtriplett``

…askrgr Rollup of 8 pull requests Successful merges: - rust-lang#89446 (Add paragraph to ControlFlow docs to menion it works with the ? operator (rust-lang#88715)) - rust-lang#89677 (Stabilize `is_symlink()` for `Metadata` and `Path`) - rust-lang#89833 (Add #[must_use] to Rc::downgrade) - rust-lang#89835 (Add #[must_use] to expensive computations) - rust-lang#89839 (Add #[must_use] to mem/ptr functions) - rust-lang#89897 (Add #[must_use] to remaining core functions) - rust-lang#89951 (Stabilize `option_result_unwrap_unchecked`) - rust-lang#90427 (Add #[must_use] to alloc functions that would leak memory) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

rust-highfive assigned joshtriplett Oct 12, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 12, 2021

jkugelman mentioned this pull request Oct 12, 2021

Tracking issue for adding #[must_use] annotations throughout the standard library #89692

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taiki-e reviewed Oct 13, 2021

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jkugelman force-pushed the must-use-expensive-computations branch from ca41c6c to 5ebe8d8 Compare October 13, 2021 02:39

taiki-e reviewed Oct 13, 2021

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jkugelman force-pushed the must-use-expensive-computations branch from 5ebe8d8 to 21f4677 Compare October 13, 2021 03:28

apiraino added the T-libs Relevant to the library team, which will review and decide on the PR/issue. label Oct 14, 2021

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 30, 2021

joshtriplett added the relnotes Marks issues that should be documented in the release notes of the next release. label Oct 30, 2021

matthiaskrgr mentioned this pull request Oct 31, 2021

Rollup of 8 pull requests #90426

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matthiaskrgr mentioned this pull request Oct 31, 2021

Rollup of 7 pull requests #90428

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matthiaskrgr mentioned this pull request Oct 31, 2021

Rollup of 8 pull requests #90434

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bors merged commit a26b1d2 into rust-lang:master Oct 31, 2021

rustbot added this to the 1.58.0 milestone Oct 31, 2021

jkugelman deleted the must-use-expensive-computations branch October 31, 2021 14:38

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Add #[must_use] to expensive computations #89835

Add #[must_use] to expensive computations #89835

jkugelman commented Oct 12, 2021 •

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joshtriplett commented Oct 30, 2021

bors commented Oct 30, 2021

Add #[must_use] to expensive computations #89835

Add #[must_use] to expensive computations #89835

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jkugelman commented Oct 12, 2021 • edited Loading

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bors commented Oct 30, 2021

jkugelman commented Oct 12, 2021 •

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