D-Programming-Language/dmd — pull request #2128 by donc (2013-06-04 05:04:47+00:00)
Title: CTFE: Allow creation (but not reading) of unions and __vectors

Part of my project to unify const folding and CTFE.

Allow the no-op cases for unions and __vector which are supported by optimize(WANTinterpret) but not be CTFE,
They just pass the literal through, unaltered.