height and vertical position are ambiguous for UIStackView

If this is for a UIStackView make sure you are using addArrangedSubview and not addSubview

For me I received the following error:

warning: Ambiguous Layout: Position and size are ambiguous for 'Button'.

Where the button was placed inside a stack view in Interface Builder. The problem was that I had checked "Hidden" in Interface Builder which meant Xcode was freaking out saying position and size are ambiguous. Just uncheck "Hidden" on the stack view and the warning will disappear... Magic! ✨