Trailing comma on match block goes missing when guard is on its own line

[ulyssa]

After making some changes to a guard on a match arm, I noticed that rustfmt was removing a comma from the end of the block even though I had match_block_trailing_comma set to true. Here's an example program where you can see the behaviour:

fn main() {
    let val = Some(5);

    match val {
        Some(abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ) if abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ < 1000 => {
            println!("a");
        },
        Some(a) if a > 1000 => {
            println!("b");
        },
        Some(_) => {
            println!("c");
        },
        None => {
            println!("d");
        },
    }
}

Running rustfmt --emit stdout --config match_block_trailing_comma=true test.rs on this file, you can see that all branches but the one where the guard needed to be wrapped keep the comma:

fn main() {
    let val = Some(5);

    match val {
        Some(abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ)
            if abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ < 1000 =>
        {
            println!("a");
        }
        Some(a) if a > 1000 => {
            println!("b");
        },
        Some(_) => {
            println!("c");
        },
        None => {
            println!("d");
        },
    }
}

[calebcartwright]

Thanks so much for this! Was quite literally in the process of preparing the next release which will include the stabilization of this option, so thrilled to get another bug fixed preemptively.