How to set specific return type to scope in rust, if even possible?

I have this scope in the print macro that tries to find an integer between 1 and 1 billion. If it fails, it should panic.

fn main() {
    println!(
        "{}",
        {
            for i in 0..1000000000 {
                if i == 100 {
                    Some(i)
                }
            }
            None
        }
        .unwrap()
    );
}

At the line with Some(i) it has an error:

mismatched types
expected unit type `()`
        found enum `Option<{integer}>`

How can I fix this?

>Solution :

If you want to use if as an expression you have to provide an else as well.
I think you want something else though, break out of that block early.
You can do that with the recently stabilized named blocks:

fn main() {
    println!(
        "{}",
        'bl: {
            for i in 0..1000000000 {
                if i == 100 {
                    break 'bl Some(i);
                }
            }
            None
        }
        .unwrap()
    );
}