Why are compile-time constraints checked with an (inout int = 0) lambda in Phobos?

[Atila Neves]

Seriously, nobody? I'd've thought this was quite important.

On Thursday, 27 March 2014 at 05:27:50 UTC, Atila Neves wrote:
> Why the (inout int = 0) instead of an empty parameter list? I
> checkout how isInputRange was implemented and I copied the 
> idiom,
> but I'd like to know why it's like that instead of cargo 
> culting.
> Thanks,
>
> Atila