Hi all, there is currently a discussion on python-dev about letting the compiler generate more SyntaxWarnings for "obviously unintended" code. https://mail.python.org/pipermail/python-dev/2019-January/156113.html Serhiy Storchaka has written a proof-of-concept patch for CPython here: https://bugs.python.org/issue15248 I think Cython could also be improved in that regard. While we reject a few more things at compile time than CPython's compiler, we tend to be very relaxed about things that seem wrong at compile time and would most likely fail at runtime (but might not get executed). Cython is a much smarter compiler than the one in CPython, and could base such warnings on its much greater knowledge about code and types. This would be an excellent task for someone who wants to start contributing to Cython, because the infrastructure is mostly there and each little warning should be relatively easy to add together with a unit test and is a little, self-contained task all by itself. I created a ticket for it: https://github.com/cython/cython/issues/2814 Anyone interested? Stefan