Vinay Sajip <vinay_sajip@yahoo.co.uk> added the comment: New changeset 9dbf5d3bc2033940cdca35440cf08814544f81e4 by Vinay Sajip in branch '3.7': [3.7] bpo-16575: Disabled checks for union types being passed by value. (GH-17960) (GH-17970) https://github.com/python/cpython/commit/9dbf5d3bc2033940cdca35440cf08814544... ---------- _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue16575> _______________________________________