Compiling with msvc, right?
You don't get any error because the compiler uses this function instead, defined in include/utility.

Qt Code: 
  1. template<class _Ty> inline
  2.     void swap(_Ty& _Left, _Ty& _Right)
  3.     {    // exchange values stored at _Left and _Right
  4.     if (&_Left != &_Right)
  5.         {    // different, worth swapping
  6.         _Ty _Tmp = _Left;
  7.  
  8.         _Left = _Right;
  9.         _Right = _Tmp;
  10.         }
  11.     }
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Rename your function and you'll see the errors.