Linked list as a bidirectional range? I have some questions...

[Gary Willoughby via Digitalmars-d-learn]

On Monday, 11 August 2014 at 20:02:38 UTC, H. S. Teoh via 
Digitalmars-d-learn wrote:
> Anyway, clearly we're not understanding each other, so let me 
> present
> some concrete code so that we aren't just talking past each 
> other:

I've used your advice and implemented a range over the list as 
suggested, the problem being i cannot get it to pass the 
isForwardRange check.

Code: http://dpaste.dzfl.pl/cad89406bbcc#line-220

You'll notice the assert on line 220 fails. Any idea what i'm 
doing wrong?