title: NavController doesn't work in Ionic 4
body: <p>I'm injecting NavController in my constructor as I want to push a page. But, below code doesn't work in Ionic 4. It was totally okay in Ionic 3.</p>
  
  <blockquote>
    <p>Constructor</p>
  </blockquote>
  
  <pre><code>constructor(public menuCtrl: MenuController, public navCtrl: NavController) {
      this.menuCtrl.enable(true);
     }
  </code></pre>
  
  <blockquote>
    <p>Method</p>
  </blockquote>
  
  <pre><code>goToSecondPage()
    {
      this.navCtrl.push(list);
    }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/HopTg.png" rel="noreferrer"><img src="https://i.stack.imgur.com/HopTg.png" alt="Error"></a></p>