title: Cant get variable in data
body: <p>I created a function that should set a var equal to a variable in data.</p>
  
  <pre><code>export default class App extends Vue{
    data() {
      return {
        evidence: 0
      }
    }
    handleFileSelect(evt: any) {
        var evidence = this.evidence;
    }
  };
  </code></pre>
  
  <p>The problem is that it shows an error saying "Property 'evidence' does not exist on type 'App'".</p>