Is there a more concise way to format .expect() message?

Question

I currently have to use this to format a .expect() message:

fn main() {
    let x: Option<&str&g         


        

Answer 1

To avoid the unnecessary overhead of formatting and allocating a String in the case of an Ok, you can convert the Option to a Result and then unwrap it:

fn main() {
    let x: Option<&str> = None;
    x.ok_or_else(|| format!("the world is ending: {}", "foo"))
        .unwrap();
}