Message 207232 - Python tracker
This is probably the smallest example of a .py file that behaves differently in CPython vs PyPy, and for once, I'd argue that the CPython behavior is unexpected:
# make the file:
>>> open('x.py', 'wb').write('#\x00\na')
# run it:
python x.py
Expected: either some SyntaxError, or "NameError: global name 'a' is not defined". Got: nothing. It seems that CPython completely ignores the line that is immediately after a line with a '#' and a following '\x00'.