new lint: unnecessary_indexing
#14058
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| /// Use instead: | ||
| /// ```no_run | ||
| /// let a: &[i32] = &[1]; | ||
| /// if let Some(b) = a.first() { |
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Note that you can generate even simplier expressions:
- If
ais a slice ref, use:if let [b, ..] = a - If
ais an array, use:if let [b, ..] = &a - If
aderefs to a slice, use:if let [b, ..] = &a[..]
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I can add it as an alternate suggestion, which one is more preferable though?
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They're in order of preference. a is the simplest, &a is needed if a is [T] or [T; _], and &a[..] is needed for everything else.
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Ping @Alexendoo from triage. This is still waiting on a review. |
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I think also some of the points in #12464 still apply such as #12464 (comment)
| let receiver = snippet(cx, receiver_span, ".."); | ||
| let mut suggestions: Vec<(Span, String)> = vec![]; | ||
| let mut message = "consider using `if..let` syntax instead of indexing".to_string(); |
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These can be moved into the lint callback
| // span of the receiver for the index operation, only Some in the event the indexing is via a direct primitive | ||
| index_receiver_span: Option<Span>, |
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The Option here can be removed since process_indexing already returns an Option<IndexCheckResult>
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Ping @J-ZhengLi from triage. Do you plan to return to working on this? |
yes, sorry I'm in a family vacation😃, I'll get back in a few days |
do not lint after mutable reference is taken check path to local on conditional receiver, check mutable borrow after ref, do not lint on mutable auto borrow fix autoborrow/mutability checks remove unneded `extra_locals` inline if ststements; check locality earlier remove unnecessary impl on IndexCheckResult check for borrows in if block and change inner `Some` based on this
…f condition & lint messages etc.
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This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed. Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers. |
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Lintcheck changes for 4ddddab
This comment will be updated if you push new changes |
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closes: #11858
This is a continuation of #12464 (shout out to @Jacherr for their hard work)
Since they don't have time, I thought I could push this forward by adding another commit on top of it to fix some of the addressed issues.
r? Alexendoo
changelog: add new lint [
unnecessary_indexing]