front stability

[Ola Fosheim Grøstad via Digitalmars-d]

On Thursday, 30 June 2016 at 19:34:47 UTC, H. S. Teoh wrote:
> arbitrary type. It doesn't seem to make sense that the 
> assignment operator should suddenly be prohibited just because 
> it happens to have members named .front, .empty, .popFront.

Seems like this could be resolved by requiring all range code to 
use an enclosure type that wraps the range functionality.