https://issues.dlang.org/show_bug.cgi?id=17164 --- Comment #2 from Jacob Carlborg <doob at me.com> --- It's documented for D1 [1], under "C-style Variadic Functions". I still think it's a regressions, this code originated from D1. [1] http://www.digitalmars.com/d/1.0/function.html --