I have no idea why, but as soon as I switched to Xcode beta 3, I cannot get anything in my project to compile. This is what I see throughout the build log ...
: 0: error: failed to execute command: segmentation error: 11: 0: error: swift frontend command failed due to a signal (use -v to see the call) Command /Applications/Xcode6-Beta3.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift failed with exit code 254
This helped:
Xcode 6 beta 3: invalid virtual file system overlay file
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