Xcode 8 UIButtons with constraints not showing up

Question

Everything used to work great until yesterday I updated Xcode to version 8.

If I don\'t use any constraints, I can see the buttons but when I apply constraint(s) to

Answer 1

I was missing the point of setting UIButton class to my custom class. I checked my custom class and have seen that I set corner radius on awakeFromNib() method. I called layoutIfNeeded() before I set corner radius which was the solution in my case.