render_io_error.rs

fn render_docs(source: &Path, dest: &Path) -> Result<(), io::Error> {
  for entry_res in try!(read_dir(source)) {
    let entry = try!(entry_res);
    let file = try!(File::open(&entry.path());
    for line_res in file.lines() {
      let line = try!(line_res);
      // ...
      if wrong_syntax_flag {
        return Err(io::Error::new(io::ErrorKind::Other,
          "Wrong syntax"));
      }
    }
  }
  // ...
}