rust-lang / rust-lang/rust-clippy

A lint suggesting `.get(n)` instead of `if n < slice.len() { slice[n] } ...`

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A-lint
Dominant language
Rust
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Description

What it does

When recently reviewing new Rust dev code, I saw this pattern, which is a clear dup of the Slice::get. It would be great to catch it. Note that in an ideal case, we shouldn't catch this specific case, but instead catch any kind of stdlib function patterns (ASTs), and suggest replacements (this might generate some false positives though)

Advantage
  • shorter, more readable code
  • clearer intent
Drawbacks

No response

Example
pub static GLOBAL_ARRAY: [&str; ...] = [...];

fn get_item(index: usize) -> Option<&'static str> {
  if index < GLOBAL_ARRAY.len() {
    Some(GLOBAL_ARRAY[index])
  } else {
    None
  }
}

Could be written as:

fn get_item(index: usize) -> Option<&'static str> {
  GLOBAL_ARRAY.get(index)
}
Comparison with existing lints

No response

Additional Context

No response

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The issue names no files, tests, or entry points. Start by reviewing Clippy's existing lint architecture and the proposed Slice::get pattern, then narrow the broader standard-library pattern goal and its false-positive boundaries. Done means the supported scope is agreed and the lint behavior can be validated with focused examples.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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