The issue is happening because of the Xcode automatic subclass generation feature.
According to What’s New In Core Data
Xcode automatic subclass generation
Xcode now supports automatic generation of NSManagedObject subclasses
in the modeling tool. In the entity inspector:
- Manual/None is the default, and previous behavior; in this case you
should implement your own subclass or use NSManagedObject.- Category/Extension generates a class extension in a file named like
ClassName+CoreDataGeneratedProperties. You need to declare/implement
the main class (if in Obj-C, via a header the extension can import
named ClassName.h).- Class Definition generates subclass files named
like ClassName+CoreDataClass as well as the files generated for
Category/Extension.The generated files are placed in DerivedData and
rebuilt on the first build after the model is saved. They are also
indexed by Xcode, so command-clicking on references and fast-opening
by filename works.
So for fixing your issue, you need to set the Codegen field value to Manual/None as shown below:
