Redundant new line in if statement

[davidBar-On]

Input

fn main() {
    if 'a' == 0
    /* x */ as char {} }

fn main() {
    if 1234 == 'a'
    /* x */ as i32 {} }

fn main() {
    if 'a' == b // x
    as char {}
}

Output

fn main() {
    if 'a'
        == 0
    /* x */ as char
    {}
}

fn main() {
    if 1234
        == 'a'
    /* x */ as i32
    {}
}

fn main() {
    if 'a'
        == b // x
    as char
    {}
}

Expected output

fn main() {
    if 'a' == 0
    /* x */ as char
    {}
}

fn main() {
    if 1234 == 'a'
    /* x */ as i32
    {}
}

fn main() {
    if 'a' == b // x
    as char
    {}
}

Meta

• rustfmt version: rustfmt 2.0.0-rc.2-nightly (688e472 2020-08-10)
• From where did you install rustfmt?: local build from a clone (Linux WSL under Windows 10)

[davidBar-On]

The problem seem to happen in pairs.rs, rewrite_pairs_multiline() function, line 128:

    if last_line_width(&result) + offset <= nested_shape.used_width() {

For some reason the decision is that the line will exceed the allowed line size.