title: Typescript Property does not exist on enum type
body: <p>I try to upgrade the typescript syntax of 
  this lesson: <a href="https://medium.com/@martin_hotell/improved-redux-type-safety-with-typescript-2-8-2c11a8062575" rel="nofollow noreferrer">https://medium.com/@martin_hotell/improved-redux-type-safety-with-typescript-2-8-2c11a8062575</a> .</p>
  
  <p>I want to get specific type from union type. I have such syntax:</p>
  
  <pre><code>Actions['type'][ActionTypes.FEED_CREATE_POST]
  </code></pre>
  
  <p>Type actions:</p>
  
  <pre><code>type Actions = IActionWithPayload&lt;ActionTypes.FEED_CREATE_POST, {
      text: string;
      files: any;
  }&gt; | IActionWithPayload&lt;ActionTypes.FEED_GET_NEWS, {
      loadMore: boolean;
  }&gt;
  </code></pre>
  
  <p>Property 'type':</p>
  
  <pre><code>(property) type: ActionTypes.FEED_GET_NEWS | ActionTypes.FEED_CREATE_POST
  </code></pre>
  
  <p>And the mistake is: </p>
  
  <pre><code>Property 'FEED_CREATE_POST' does not exist on type 'ActionTypes.FEED_GET_NEWS | ActionTypes.FEED_CREATE_POST'.
  </code></pre>
  
  <p>What's the problem and how can i change that? Typescript version 3.1.3</p>