enum Error {
    InvalidLoginOrPassword,
    Other,
}

trait StatusOk {
    type Response;
    fn ok() -> Self::Response {
        Self::Response {
            code: 200
        }
    }
}

struct LoginForm {
    code: i32
}

impl StatusOk for LoginForm {
    type Response = Self;
}

fn login<'a>(_username: &'a str, _password: &'a str) -> Result<LoginForm, Error> {
    Ok(LoginForm::ok())
}

fn main() {
    login("Username", "Password");
}