Function returns &Option and not Option

April 21, 2022

I am a beginner in Rust and I don’t understand the behaviour I am encountering. Function number 1 should return me an Option type but returns an &Option type. I have worked around this by doing function 2 but I don’t understand why this works. What am I doing wrong in my function?

Function 1:

pub fn manage_request(&self, request:String) -> Option<Some type> {
    let words : Vec<&str> = request.split_whitespace().collect();
    match words[0] {
        "attach" => &self.hashmap.get(words[1]),
        _ => None,
    }
}

Function 2:

pub fn manage_request(&self, request:String) -> Option<Some type> {
    let words : Vec<&str> = request.split_whitespace().collect();
    match words[0] {
        "attach" => match &self.hashmap.get(words[1]){
            None => None,
            Some(x) => Some(x)
        }
        _ => None,
    }
}

Here is a link to rust playground with the code

>Solution :

Correct me if Im wrong but I think you actually did this properly but might have missed a typo.

In your playground your signature consumes self by saying fn manage_request(self). If you change this to take a reference to self like fn manage_request(&self) I believe it works.

Updated playground link runs without compiler errors: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=a5a104cc02f1f4715f4420a8ff6da1f8