isBidirectionalRange fails for unknown reasons

[Jack Stouffer via Digitalmars-d-learn]

On Wednesday, 16 December 2015 at 20:43:02 UTC, Jack Stouffer 
wrote:
> unittest
> {
>     static assert(isInputRange!(ReferenceInputRange!int)); // 
> works
>     static assert(isForwardRange!(ReferenceForwardRange!int)); 
> // works
>     static 
> assert(isBidirectionalRange!(ReferenceBidirectionalRange!int)); 
> //fails
> }

Also, this works just fine

=================
unittest
{
     auto a = new ReferenceBidirectionalRange!int([1,2]);
     a.popBack();
     a.back.writeln; // prints 1
}