D-Programming-Language/dmd — pull request #793 by donc (2012-03-10 06:25:12+00:00)
Title: 6681 - Regression with unions in CTFE

Add VoidExp to explicitly specify uninitialized variables.
When a union member is written to, set all other members of that union to VoidExp.

90% of this commit was written by yebblies. I've only added the union part.

Note: Please wait until this clears the autotester, it was not developed on my normal machine.