title: Xocde canvas crashes
body: <p>I am creating and running a simple hello world app in Xcode 11.3.1. When I try to preview it in canvas the build succeeded and the canvas collapses. I am using Catalina version 10.15.3. The same issue is shown in Xcode 11.4 beta 3.</p>
  
  <p><a href="https://i.stack.imgur.com/jQ9jf.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jQ9jf.gif" alt="enter image description here"></a></p>