D-Programming-Language/d-programming-language.org — pull request #188 by AndrejMitrovic (2012-11-06 23:16:07+00:00)
Title: Fix Issue 8969 - Document __parameters in is expression.

http://d.puremagic.com/issues/show_bug.cgi?id=8969

I don't know if this is D2 only or not though.