duplicate interface declaration for class 'test_coredataAppDelegate'

Question

two errors suddenly fired in this piece of code - duplicate interface declaration for class \'test_coredataAppDelegate\' - redefinition of \'struct test_coredataAppDelegat

Answer 1

This happen because you have a copy of that resource in your finder. It is not necessary had added it in your project. You should find in your finder the files with the same name and delete the files duplicated.