Describe the bug

When formatting a single-line block expression with a #[cfg(...)] attribute before it, an extra open brace is produced.

To Reproduce

main.rs:

fn main() {
    #[cfg(debug_assertions)]
    { println!("DEBUG"); }
}

Run rustfmt main.rs

main.rs now contains:

fn main() {
    #[cfg(debug_assertions)]
    {
{        println!("DEBUG");
    }
}

Expected behavior

The braces are put onto different lines correctly

Meta

• rustfmt version: rustfmt 1.4.22-nightly (97d03010 2020-10-04)

• From where did you install rustfmt?: I think cargo

• How do you run rustfmt:

  I tried with both cargo fmt and rustfmt. Both do the same