title: Swift had fatal errors constructing the ast context for this module
body: <p>I upgraded my project to Swift 2 in Xcode 7 beta (7A120f) and get this error when trying to <strong>po self</strong> at the lldb prompt:</p>
  <blockquote>
  <p>warning: Swift error in module myApp:</p>
  <p>Swift had fatal errors constructing the ast context for this module: cannot load underlying module for 'UIKit'
  Debug info from this module will be unavailable in the debugger.</p>
  </blockquote>
  <p>I'm then left with a crippled debugger (no values). This happens regardless of where I place a breakpoint. I've tried:</p>
  <ul>
  <li>clearing derived data</li>
  <li>Product &gt; Clean</li>
  <li>restarting xcode</li>
  <li>restarting mac</li>
  </ul>
  <p>I'm able to create a new project and see debug output in it, so this probably has something to do with how my project was migrated by xcode.</p>
  <p>What is the ast context and how can I correct it?</p>
  <p><strong>Edit:</strong> ast is 'Abstract Syntax Tree'. Still no idea how to fix it though.</p>