Vinay Sajip <vinay_sajip@yahoo.co.uk> added the comment: New changeset c12440c371025bea9c3bfb94945f006c486c2c01 by Vinay Sajip in branch 'master': bpo-16575: Disabled checks for union types being passed by value. (GH-17960) https://github.com/python/cpython/commit/c12440c371025bea9c3bfb94945f006c486... ---------- _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue16575> _______________________________________