More tricky range semantics

[Andrei Alexandrescu via Digitalmars-d]

On 1/15/15 12:53 PM, H. S. Teoh via Digitalmars-d wrote:
> This issue is already latent in almost*all*  Phobos algorithms.  We
> only haven't discovered it yet because most people just use arrays for
> ranges. But all it takes is for somebody to start using
> std.range.inputRangeObject (and there are cases where this is
> necessary), and this problem will surface.

There's a distinction here. Input non-forward ranges can be considered 
"reference" because popFront()ing any copy is tantamount to 
popFront()int any other copy. -- Andrei