Fail to format match arm when other arm has long line

[programmerjake]

Rustfmt is not formatting the let a=0; part in this reduced testcase:

fn f() {
    let mut a = Vec::new();
    a.push(match 0 {
        0 => {let a=0;""}
        _ => r#"
--------------------loong line----------------------------------------------------------------------.
"#,
    });
}

I am using rustfmt version:
rustfmt 0.99.6-nightly (750b252 2018-10-18)

[VeaaC]

Might be a duplicate of/related to #3135

[ytmimi]

I can confirm that this is reproducible on rustfmt 1.5.1-nightly (a7bf0090 2022-07-17). The input from the issue description is left unchanged.

[ytmimi]

I believe this is also a duplicate of #3416 and #3863

If we remove the call to a.push in the example above rustfmt is able to format the match statement, which leads me to believe that we're dealing with the same issue as #3416 and #3863.

Input

fn f() {
    let mut a = Vec::new();
    match 0 {
        0 => {let a=0;""}
        _ => r#"
--------------------loong line----------------------------------------------------------------------.
"#,
    };
}

Output

fn f() {
    let mut a = Vec::new();
    match 0 {
        0 => {
            let a = 0;
            ""
        }
        _ => {
            r#"
--------------------loong line----------------------------------------------------------------------.
"#
        }
    };
}