main.rs

struct Line {
    next: Option<&Line>, // error: missing lifetime specifier [E0106]
    prev: Option<&Line>, // error: missing lifetime specifier [E0106]
    data: Option<String>,
}

fn main() {
    let l = Line { next: None, prev: None, data: "test".to_string() };

    println!("{}", l.data);
}