Apparently, module-enabled builds clash with Xcode's analysis.
You might want to check with Argyrios, maybe file a rdar against SourceKit.
Otherwise, this is fine to me.
Do we have a radar tracking the SourceKit issue? This *should* work and I'm curious if this is actually SourceKit or if this is just a broken LLVM+modules build.
Did you manage to file a rdar for this issue? If so, can you put the link here for future archeology?