rust-lang / rust-lang/rustfmt

Adding an attribute to an `unsafe` block changes its formatting

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I-poor-formatting
Dominant language
Rust
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Description

This is the rustfmt result for an unsafe block:

fn main() {
    // #[cfg(not(fake_flag))]
    unsafe { println!() };
}

But uncomment the attribute, and it reformats it as:

fn main() {
    #[cfg(not(fake_flag))]
    unsafe {
        println!()
    };
}

Changing the attribute probably should not change the formatting.

rustfmt 1.7.0-nightly (5119208f 2024-03-02)

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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 reproducing the two unsafe-block examples with the reported rustfmt version, comparing output with and without the cfg attribute. Trace the rustfmt formatting entry point for attributed unsafe blocks and add or update coverage so equivalent blocks receive consistent formatting.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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