I had set the class of an XIB's "view" to my custom class by mistake(instead of setting file's owner to my custom class). Later I corrected it by setting the XIB's view's class to UIView and setting file Owner's class to my custom Classes (and not the classes already present in swift). you can see the console shows unknown class error for my custom classes only. Also, how the app crashes only and as when the setUpLayout() is called
I had to remove all connections and reconnect the outlets. Now my app is crashing at the first line of my xib's setUpLayout() function. I have tried checking Module, "inherited From target" check, target membership.