{"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"println!(\"{{{}}}\","}]}
    println!("{{{}}}", 2);                       // => "{2}"
    println!("{a} {c} {b}", a="a", b='b', c=3);  // => "a 3 b"
    println!("Hello {:5}!", "x");