title: functions that return promises must be async
body: <p>When I run tslint on my code I get the following error</p>
  
  <pre><code>functions that return promises must be async
  </code></pre>
  
  <p>Here is the code</p>
  
  <pre><code>private doSomething(): void {
      fetch(myUrl)
          .then((rsp: Response) =&gt; rsp.text()) // &lt;-- gives error
          .then(txt =&gt; this.txt = txt);
  }
  </code></pre>
  
  <p>Not sure now how to fix this because the code runs just fine! Any suggestions ?</p>