Can't figure out where SyntaxError: can not delete variable 'x' referenced in nested scope us coming from in python >=2.6

[Albert Hopkins]

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.

The reason why I ask is... I have a python package, 'foo', with
__init__.py and a whole bunch of other modules.  It runs fine on Python
2.4 as well as 2.6, but when I run 2to3 on my foo directory and try to
'import foo' in Python 3 I get no traceback, I can't 'import foo' in
Python 2 because 'foo' is no longer Python2-compatible, but my original
Python2 version of foo imports just fine.

So is there a way to find the offending code w/o having to go through
every line of code in 'foo' by hand?  I've tried using pdb but it just
breaks out of the debugger.

thanks,
-a