Obviously this wasn't anything you did, and I have no idea why we have a custom stack class anyway (rather than using std::stack or QStack), but it's pretty bizarre to have both isEmpty and empty, and both count and size.  If you could get rid of empty (keeping isEmpty) and count, and rename size to getSize, that would help.  Or just get rid of the class entirely, find out where it's used, and replace those instances with std::stack/QStack.