While investigating https://bitbucket.org/pypa/setuptools/issue/388/install-from-sdist-fails-on-python-350b1 I noticed that Grammar/Grammar changed in 3.5, but Lib/symbol.py wasn't updated.

I'm not familiar with the CPython parser, but I suspect that adding/removing/splitting grammar rules causes the nonterminal symbol IDs to shift, which ought to require an update in symbol.py.

Huh.  Now I see a comment in the file says it is automatically generated, but in that case why wasn't that done when I did 'hg pull -u && make && make install'?  Why is it checked into source control?