Xcode 6 Beta / Swift - Playground not updating

Question

I was playing around with the Playground feature of Xcode 6\'s first beta - and I notice half the time the Playground doesn\'t update (simply doesn\'t display the result calcula

Answer 1

This answer (Undeclared Type 'NSView' in Playground) did it for me (restarting Xcode and the machine didn't help):

rm -rf "$(getconf DARWIN_USER_CACHE_DIR)/org.llvm.clang/ModuleCache"