rust-lang / rust-lang/rust-clippy

Extend `collapsible_if` to cover nested `if`s with identical `else`

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C-enhancement
Dominant language
Rust
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Avg merge
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Merged PRs (30d)
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Description

Extend collapsible_if to cover nested ifs with identical else

For example:

let opt = Some(1);
let _ = if let Some(s) = opt {
    if s == 1 { s } else { 1 }
} else {
    1
};

Use instead:

let opt = Some(1);
let _ = if let Some(s) = opt
    && s == 1
{
    s
} else {
    1
};

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

Start by locating the collapsible_if lint implementation and its existing tests. Compare the nested-if example with the requested combined condition, then add coverage for identical else branches and verify that the lint produces the shown transformation without changing other cases.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
48/100

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