ld: -bundle and -bitcode_bundle (Xcode setting ENABLE_BITCODE=YES) cannot be used together
I had erroneously set my DEBUG and TEST configurations to build with Bitcode, and this was what caused the above error. Enabling Bitcode only for RELEASE fixed it:
(Your App and any embedded framework targets should look like this—don't enable Bitcode at all on your test and UI testing targets.)