title: VSCode PHP Intelephense show error when using Memcached
body: <p>I'm using Memcached in code, it shows this: </p>
  
  <blockquote>
    <p>error: "Undefined type 'Memcached'."</p>
  </blockquote>
  
  <p>How to disable this error?
  Version using:
  VScode 1.41
  PHP Intelephense 1.3.5</p>
  
  <p><a href="https://i.stack.imgur.com/Hrjmd.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Hrjmd.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/wRo8R.png" rel="noreferrer"><img src="https://i.stack.imgur.com/wRo8R.png" alt="enter image description here"></a></p>