The output of running the program:
$ cargo run
fn main() {
let x = "fn main() {\n let x = ";
let y = "print!(\"{}{:?};\n let y = {:?};\n {}\", x, x, y, y)\n}\n";
print!("{}{:?};
let y = {:?};
{}", x, x, y, y)
}
is the same as the source of the program itself:
$ cat quine.rs
fn main() {
let x = "fn main() {\n let x = ";
let y = "print!(\"{}{:?};\n let y = {:?};\n {}\", x, x, y, y)\n}\n";
print!("{}{:?};
let y = {:?};
{}", x, x, y, y)
}