rust-lang / rust-lang/rustfmt

Comments inside a function do not wrap whenever macro attributes are applied to the outside of the function

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#3,965 2 comments 0 reactions 0 assignees View on GitHub

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A-macros I-poor-formatting only-with-option P-low
Dominant language
Rust
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Description

in .rustfmt.toml:

comment_width = 80
error_on_line_overflow = true
error_on_unformatted = true
max_width = 100
wrap_comments = true

in main.rs:

macro_rules! impl_stuff {
    (
        $($attributes:meta),*;
    ) => {
        $(
            #[$attributes]
        )*
        pub fn y_u_no_format() {
            // Wrapping long comments by hand every time indentation changes is very annoying, and rustfmt normally helps with this,
            // but for some reason refuses when the `$(#[$attributes])*` is attached to the function.
        }
    }
}

fn main() {}

It makes no sense to me why this would affect formatting inside the function, the code compiles just fine.

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Research direction

Reproduce the report using the shown .rustfmt.toml and main.rs, then inspect rustfmt's handling of macro attributes and comments inside the generated function. Confirm the behavior against the long comment with wrap_comments enabled. Done means the comment wraps despite the outer attributes, without violating the configured overflow and formatting checks.

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
35/100

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