No closure for unused vars, even with eval

no-closure-eval.py

# Python does not save not used bindings in
# the closured environment. However, even
# `eval` doesn't help to save them.
#
# In contrast, ECMAScript having environments
# frames, normaly find variable "x", see
# the same ES example here: https://gist.github.com/734485
#
# by Dmitry A. Soshnikov
#
# See detailed explanation of closures
# in Python here: https://gist.github.com/700292
#

def foo(x):

    def bar(y):
        print(eval(k))

    return bar

bar = foo(10)
print(bar.__closure__) # None

k = "y"

bar(20) # OK, 20

k = "x"

bar(20), # error, "x" is not defined