D-Programming-Language/dmd — pull request #3168 by 9rnsr (2014-01-28 07:39:05+00:00)
Title: [REG2.065a] Issue 12016 - implicit immutable upcast becomes null in CTFE

https://d.puremagic.com/issues/show_bug.cgi?id=12016

It is an interpreter bug that revealed by the change #2749.