> enum b = DataAndView(1); > assert (!sameTail(b.data, b.view));
I suppose it's because enums are manifest constants: the value they represent is 'copy-pasted' anew everywhere it appears in the code. So for arrays and associative arrays, it means recreating a new value each and every time. In your case, your code is equivalent to: assert (!sameTail(DataAndView(1).data,DataAndView(1).view)); And the two DataAndView(1), being completely separated, do not have the same tail.