The code migration tool for Swift 3.0 is not working in Xcode 8

Number:rdar://28573366 Date Originated:9/30/2016
Status:Open Resolved:NO
Product:Xcode Product Version:8.1
Classification: Reproducible:YES
The Xcode code conversion tool will not convert my codebase from Swift 2.3 to Swift 3.0.  The process appears to hang while trying to generate the preview of the changes.

Steps to Reproduce:
1. Run Convert To Current Swift Syntax from the Edit > Convert menu in Xcode.
2. Select Convert to Swift 3.
3. Select the main project target.
4. Message Generating preview... shows with the progress spinner.
The preview never gets generated, even after letting it run for over 8 hours.

Expected Results:
A preview of the Swift 2.3 to 3.0 changes should be generated and allow me to apply the changes to my code.

Actual Results:
A preview is never generated and I'm not able to convert my code to Swift 3.0 using the code migration tool.

Xcode 8.1 beta (8T29o) / OS X El Capitan version 10.11.6


This issue occurs 100% of the time and I have had another developer confirm the issue on their machine running Xcode 8 on macOS Sierra


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