#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::fmt;
struct Foo(i32);
impl fmt::Display for Foo {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        if formatter.sign_plus() {
            write!(
                formatter, "Foo({}{})", if self.0 < 0 { '-' } else { '+' }, self.0.abs()
            )
        } else {
            write!(formatter, "Foo({})", self.0)
        }
    }
}
fn main() {
    assert_eq!(format!("{:+}", Foo(23)), "Foo(+23)");
    assert_eq!(format!("{:+}", Foo(- 23)), "Foo(-23)");
    assert_eq!(format!("{}", Foo(23)), "Foo(23)");
}