D-Programming-Language/dmd — pull request #746 by yebblies (2012-02-20 11:18:21+00:00)
Title: Issue 5554 - [qtd] Covariance detection failure

The functions match is A is a base class of B, _or_ if B is a base class of A.

http://d.puremagic.com/issues/show_bug.cgi?id=5554