`react-native run-ios` command fails (PCH issues), but build succeeds in xcode

You have to delete the derived data folder.

Sorry to answer my own, but turns out it's safe to just delete the whole build directory at /path/to/project/ios/build. After that it rebuilt fine for me :)

No need to delete whole build directory but delete ModuleCache folder at /path/to/project/ios/build/ModuleCache and then react-native run-ios worked for me.