Say I have module foo.py:

        def a(x):
           def b():
               x
           del x
        
If I run foo.py under Python 2.4.4 I get:

          File "foo.py", line 4
            del x
        SyntaxError: can not delete variable 'x' referenced in nested
        scope

Under Python 2.6 and Python 3.0 I get:

        SyntaxError: can not delete variable 'x' referenced in nested
        scope


The difference is under Python 2.4 I get a traceback with the lineno and
offending line, but I do not get a traceback in Pythons 2.6 and 3.0.

This also kinda relates to the 2to3 tool.  See:

http://groups.google.com/group/comp.lang.python/browse_frm/thread/a6600c80f8c3c60c/4d804532ea09aae7