Bug: rustfmt complains that fn_call_width is bigger than max_width when it isn't

[bergkvist]

When running cargo fmt, I get the following warning message printed out to my terminal:

`fn_call_width` cannot have a value that exceeds `max_width`. `fn_call_width` will be set to the same value as `max_width`

rust version 1.78.0-nightly (ee9c7c940 2024-02-14)

The following macro somehow triggers the warning:

mod a {
    macro_rules! b {
        () => {};
    }
}

When you have a .rustfmt.toml config set up file like this:

max_width = 100
fn_call_width = 90

Increasing max_width to 102, or changing the macro to the following will make the warning go away:

mod a {
    macro_rules! b {
        () => {{}};
    }
}

See this repo for how to reproduce:
https://github.com/bergkvist/rustfmt-bug

[bergkvist]

Seems like this might be caused by the following:

// max_width here is 100
// fn_call_width here is 90
mod a {
    // max_width here is 96
    // fn_call_width here is 90
    macro_rules! b {
        () => {
            // max_width here is 88
            // fn_call_width here is 90
        };
    }
}

[bergkvist]

This seems like it is caused by the same problem as #5404.

[ytmimi]

Thanks for the report! Right, this is likely a duplicate of #5404 so I'm going to close this one.