PEP 7 requires CPython to use C code conforming to the venerable C89 standard. Traditionally, we've been stuck with C89 due to poor C support in MSVC. However, MSVC 2013 and 2015 implement the key features of C99. C99 does not offer anything earth-shattering; here are the features I think we'd find most interesting: - Variable declarations can be on any line: removes possibly the most annoying limitation of C89. - Inline functions: We can make Py_DECREF and Py_INCREF inline functions rather than unpleasant macros. - C++-style line comments: Not an killer feature but commonly used. - Booleans In summary, some niceties that would make CPython hacking a little more fun. So, what say you to updating PEP 7 to allow C99 features for Python 3.6 (in so much as GCC and MSVC support them)? Regards, Benjamin