macOS Cannot find protocol declaration!

I made a delegate for a custom class, and I used a formal protocol declaration. However, when I make a class conform to that protocol, I get an error that the declaration was not found, and it is there!!!!

Well, after looking at my #import statements, I realized that the problem was a strange import loop, where I should have used @class. Thanks for pointing me in the right direction!

It's funny how problems seem so much simpler here.