I have read countless posts where developers are stuck after deleting their Objective-C Bridging Header file. The bridging header basically provides a way for Swift code to call Objective-C code. If however you delete the bridging header by accident then your app will NOT compile. The reason it does not compile is because the app is still looking for that bridging header.
You can easily fix that by removing the Objective-C Bridging Header entry from the Build Settings.
Hope it helps!