rust-lang / rust-lang/rustfmt

Unclear message for comments with trailing spaces

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#6,545 1 comment 0 reactions 0 assignees View on GitHub

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

When a comment ends with a trailing whitespace, cargo fmt --check gives an unclear error message.

fn main() {
    // Comment with trailing whitespace 
    println!("Hello world");
}

Error message:

Image

output of rustfmt -V on my machine: rustfmt 1.8.0-nightly (b48576b4db 2025-03-22)

I think there are Unicode characters that can be used to represent unwanted spaces, like U+2423, U+23B5 or U+25AF

Contributor guide

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the provided Rust reproducer and run cargo fmt --check or rustfmt on the snippet to inspect the current diagnostic. The work is done when trailing whitespace in a comment produces a clear indication of the unwanted character or its location.

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
38/100

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