Attempting to run Playground using Xcode 7 beta 4 using iOS as a platfoorm is failing. I attempted to Delete the content of the "Derived Data" directory as well as deleted the content of "~/Library/Developer/CoreSimulator/Devices". Deleted and re-installed Xcode 7 numerous times with no such luck.
If I change the platform to "OSX" and comment out "import UIKit" then it works, otherwise it failes and produces the error dialogue with the message "Playground execution terminated because the process stopped unexpectedly".
The same playground file runs just fine under iOS or OSX platform in Xcode 6.4.
Any assistance would be much appreciated.
Update: It appears that this playground issue is related to the latest OSX Yosemite Pre-release update seed 10.10.5 (14F19a). I just updated a secondary mac with the latest Yosemite seed and the version of Xcode 7 (beta 1) that I had installed exhibited the same issue as above. Something in Xcode 7 is not playing nice with this latest seed.
Bug report # 22107530 submitted.