Fix loses exists guard for move_guard

[A4-Tacks]

Example

fn main() {
    let cond = true;
    match 92 {
        3 => true,
        x if cond => if x $0> 10 {
            false
        } else if x > 5 {
            true
        } else if x > 4 || x < -2 {
            false
        } else {
            true
        },
    }
}

Before this PR

fn main() {
    let cond = true;
    match 92 {
        3 => true,
        x if x > 10 => false,
        x if x > 5 => true,
        x if x > 4 || x < -2 => false,
        x => true,
    }
}

After this PR

fn main() {
    let cond = true;
    match 92 {
        3 => true,
        x if cond && x > 10 => false,
        x if cond && x > 5 => true,
        x if cond && (x > 4 || x < -2) => false,
        x if cond => true,
    }
}