scalaz/scalaz — pull request #546 by S11001001 (2013-09-25 05:09:58+00:00)
Title: Don't break SI-7872

I noticed something about 227a192, and reduced & reported it in [SI-7872](https://issues.scala-lang.org/browse/SI-7872).

So, ah, here is some new variance, to work around some variance issues. Erm.

bc2d3e4 is probably worthy of #473.