How to provide this arg or functor for algorithm?

[thedeemon via Digitalmars-d-learn]

On Monday, 17 August 2015 at 09:51:47 UTC, anonymous wrote:
> Huh. I think func being a template is the key here. When the 
> original code is put in a template, it works too (with 2.068):

Nope, it "works" only because "r" is unreferenced and gets thrown 
out. Just try using r.front there, for example, and the error 
returns.