title: Var init in do-catch
body: <p>Following code:</p>
  
  <pre><code>// Setup components
  do {
      let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
      let deviceInput   = try AVCaptureDeviceInput(device: captureDevice)
      let output        = AVCaptureMetadataOutput()
      let session       = AVCaptureSession()
  } catch {
      return false
  }
  </code></pre>
  
  <p>After this you can't access the initialized variables. The error is "Use of unresolved identifier" if I want to access e.g. <code>deviceInput</code>. But why? Either <code>AVCaptureDeviceInput()</code> crashes and the catch-Block returns or all is right and the variables are successfully initialized. What's the best solution to solve this ?</p>