``` rust fn main() { println!("Hello, world!"); let } ``` It outputs ``` src/main.rs:4:1: 4:2 error: unexpected token: `<eof>` src/main.rs:4 } ^ src/main.rs:4:1: 4:2 error: unexpected token: `<eof>` src/main.rs:4 } ^ ``` again and again. It does not stop. ``` rustc 1.8.0-nightly (57c357d89 2016-02-16) ```