> I think Raymond's original concern still applies: The macros do add to the learning curve.

I agree. But alternative solution is Victor's original patch which replaces potential bugs by inlined body of Py_REPLACE/Py_XREPLACE. This is explicit, but more verbose (2 lines are replaced by 5 lines with one new variable, with macros it would be one line), less clear and more errorprone.

I believe that given the popularity of such a code and the possibility of mistakes, it is worth introducing special macros. Here apply the same reasoning as for Py_CLEAR.

Of course these macros shouldn't be a part of stable API in 2.7 and 3.3 (and may be even in 3.4).