message: Use 301 redirects when redirect target is /latest/
diff: @@ -71,7 +71,12 @@ pub fn rustdoc_redirector_handler(req: &mut Request) -> IronResult<Response> {
  url_str.push_str(query);
  }
  let url = ctry!(req, Url::parse(&url_str));
  - let mut resp = Response::with((status::Found, Redirect(url)));
  + let status_code = if vers == "latest" {
  + status::MovedPermanently
  + } else {
  + status::Found
  + };
  + let mut resp = Response::with((status_code, Redirect(url)));
  resp.headers.set(Expires(HttpDate(time::now())));
  Ok(resp)
  