Here's what happens:
I tried to create an IBAction method in my view controller without success. It just does not connect.
Additional info: Xcode 9.0 (beta) running on macOS 10.13 (beta)
Could you please check if you set WelcomeViewController
as class in your view controller object in Storyboard.
You can check this in your Identity Inspector tab in storyboard.
If NOT please set the class and try connecting.
OR, If nothing works write the IBAction in class and go to storyboard > Connection Inspector tab and connect it from there by performing drag and drop from reference in connection inspector to button.