Rust issue

git.rs

pub fn read_file(path: &str) -> IoResult<String> {
    let basepath = Path::new(".git");
    File::open(&basepath.join(path)).read_to_string()
}

pub enum HeadState {
    Detached(String),
    Attached(String)
}

pub fn read_head() -> HeadState {
    let head = read_file("HEAD").unwrap();
    let head_slice = head.as_slice();
    let re = regex!(r"ref: (.+)");
    match re.captures(head_slice) {
        None => {
            HeadState::Detached(head.clone())
        },

        Some(captures) => {
            HeadState::Attached(captures.at(1).unwrap().to_string())
        }
    }
}