XCode custom segue class stuck
This was what worked for me - I had to select the segue in interface builder and set the module from "None" to my project name, which appeared in the dropdown.
The answer is to reset the storyboard target membership, then reset the simulator.
For others that came from the web searching for the answer: check if you have included implementation file in Build Phases. In my case, I had several targets and the second target was missing this implementation file.