I am using Xcode 10 and no CocoaPods.
<unknown>:0: error: no such file or directory: '/Users/XXXXXXXXXXXXX/Library/Developer/Xcode/DerivedData/iOS_Belt_-_MyEvents-eektunqbfhmzjabcmfpiscjsxlyf/Build/Intermediates.noindex/iOS Belt - MyEvents.build/Debug-iphonesimulator/iOS Belt - MyEvents.build/DerivedSources/CoreDataGenerated/iOS_Belt___MyEvents/iOS_Belt___MyEvents+CoreDataModel.swift'
Command CompileSwiftSources failed with a nonzero exit code