Consider this:

namespace A {
  namespace B {
    namespace C {
      int x = 5;

      int nsfunc () {
	return x;
      }
    }
  }
}

namespace Q = A::B;

int xfun() {
  return Q::C::x;		// Breakpoint xfun
}

using namespace Q::C;

int yfun() {
  return x;			// Breakpoint yfun
}

int main(){
  return xfun() + yfun();
}


If you stop in xfun, then "print x" should fail.
Currently it prints A::B::C::x.

The bug here is that "using" statements aren't properly scoped.
Implementing this would probably require something like the macro
code's scope stuff to be available for using / blocks as well.