Issue 38970: [PDB] NameError in list comprehension in PDB

Related to https://bugs.python.org/issue27316

This code works from the repl:
Python 3.7.4 (default, Oct  4 2019, 06:57:26) 
[GCC 9.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pdb; pdb.set_trace()
--Return--
> <stdin>(1)<module>()->None
(Pdb) z = True
(Pdb) [x for x in [1,2] if z]
[1, 2]
(Pdb) 

However in my (turbogears2) wsgi application it raises:
(Pdb) z = True
(Pdb) [x for x in [1,2] if z]
*** NameError: name 'z' is not defined
(Pdb) z
True
(Pdb) 

I don't know how to report the issue in a reproducible way.
Thanks