rust-lang / rust-lang/rust-clippy

selecting a variable via an integer should be using indexing instead

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#2,512 2 comments 0 reactions 0 assignees View on GitHub

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A-lint L-unnecessary T-middle
Dominant language
Rust
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Description

I just wrote

if foo == 0 {
    a
} else {
    assert_eq!(foo, 1);
    b
}

which should be

[a, b][foo]

This only applies if a and b do not depend on foo and are simple (e.g. just naming a variable).

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Research direction

The issue names no implementation files or tests. Start by locating Clippy's lint implementations and tests for expression-selection suggestions, then inspect how conditions and simple operands are represented. Done means recognizing the described pattern only when operands do not depend on foo and suggesting equivalent indexing.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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