#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::io::Write;
fn main() -> std::io::Result<()> {
    let mut w = Vec::new();
    write!(& mut w, "test")?;
    write!(& mut w, "formatted {}", "arguments")?;
    assert_eq!(w, b"testformatted arguments");
    Ok(())
}