rust-lang / rust-lang/rustfmt

[Feature request] Chained closure formatting

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#5,685 3 comments 0 reactions 0 assignees View on GitHub

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A-closures C-feature-request P-low
Dominant language
Rust
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Forks
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Avg merge
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Merged PRs (30d)
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Description

Today, chained closure are formatted like this:

let closure = |a| {
    |b| {
        println!("{a}{b}");
    }
};

I personally find it less readable than:

let closure = |a| |b| {
    println!("{a}{b}");
};

Could it be an option for this formatting?

Contributor guide

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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 tracing how rustfmt formats chained closures and how formatter options are defined and tested. Compare the current and requested examples, then identify the existing configuration-test entry point for adding an option. Done means the option reliably selects the requested compact formatting without changing the default behavior.

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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