I had the same problem, but not the same fix.
The project folder was kinda corrupted so i had to copy my project folder to another folder, for example your desktop and after that open the project.
When it opened go to your interface builder project and you will see he recognise your script, Then you click indeed on the name of your script and press enter, u will see the module input will fill it self.
And it will work like a charm! :D