answer a question from a comment

diff --git a/Python/ceval.c b/Python/ceval.c
index 99dfc2d3b43db9f68f098a0ea70145e6614c8681..cc1eb97fe0b1a492b33533a6fb4e3ee63c37cdfd 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -3659,9 +3659,9 @@ call_function(PyObject ***pp_stack, int oparg
                Py_DECREF(func);
        }
 
-       /* Clear the stack of the function object and the arguments,
-          in case they weren't consumed already.
-          XXX(twouters) when are they not consumed already?
+       /* Clear the stack of the function object.  Also removes
+           the arguments in case they weren't consumed already
+           (fast_function() and err_args() leave them on the stack).
         */
        while ((*pp_stack) > pfunc) {
                w = EXT_POP(*pp_stack);