D-Programming-Language/dmd — pull request #803 by donc (2012-03-12 09:04:38+00:00)
Title: Fix issue 6681 - struct constructor call is converted to struct literal ...

...that breaks union initialization

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.

There are some hard cases which this doesn't fix, but it fixes all of the regressions.
Please don't merge this until it has passed on the pull autotester.