message: Optimize code by clippy hint.
diff: @@ -34,7 +34,7 @@ const CACHE_PATH: &str = ".spotify_cache/";
  fn cache_path(cookies: Cookies) -> PathBuf {
  let project_dir_path = env::current_dir().unwrap();
  - let mut cache_path = PathBuf::from(project_dir_path);
  + let mut cache_path = project_dir_path;
  cache_path.push(CACHE_PATH);
  let cache_dir = cache_path.display().to_string();
  cache_path.push(cookies.get("uuid").unwrap().value());
  @@ -45,9 +45,9 @@ fn cache_path(cookies: Cookies) -> PathBuf {
  cache_path
  }
  -fn remove_cache_path(mut cookies: Cookies) -> () {
  +fn remove_cache_path(mut cookies: Cookies) {
  let project_dir_path = env::current_dir().unwrap();
  - let mut cache_path = PathBuf::from(project_dir_path);
  + let mut cache_path = project_dir_path;
  cache_path.push(CACHE_PATH);
  let cache_dir = cache_path.display().to_string();
  if Path::new(cache_dir.as_str()).exists() {
  @@ -73,8 +73,8 @@ fn init_spotify(cookies: Cookies) -> Spotify {
  .unwrap();
  SpotifyBuilder::default()
  - .credentials(creds.clone())
  - .oauth(oauth.clone())
  + .credentials(creds)
  + .oauth(oauth)
  .cache_path(cache_path(cookies))
  .build()
  .unwrap()
  @@ -97,7 +97,7 @@ fn callback(cookies: Cookies, code: String) -> AppResponse {
  #[get("/")]
  fn index(mut cookies: Cookies) -> AppResponse {
  let cookie = cookies.get("uuid");
  - if let None = cookie {
  + if cookie.is_none() {
  cookies.add(Cookie::new("uuid", util::generate_random_string(64)));
  }
  let spotify = init_spotify(cookies);
  @@ -106,7 +106,7 @@ fn index(mut cookies: Cookies) -> AppResponse {
  Ok(user_info) => {
  context.insert(
  "display_name",
  - user_info.display_name.unwrap_or(String::from("Dear")),
  + user_info.display_name.unwrap_or_else(||String::from("Dear")),
  );
  AppResponse::Template(Template::render("index", context.clone()))
  }
  