Thorsten Ottosen wrote:
3. consider if the primary template should not take 1 range parameter and call hash_range; unordered containers can then be explicitly overloaded when they become available. this would also have the great effect that subranges like sub_range<string> "just works" by default
I don't remember this being discussed during the review, could you please explain it in more detail? Do you mean that hash_value should have a primary template that assumes that its argument is a range? If so, I strongly oppose it. Ranges aren't special from the point of view of hash_value, they shouldn't monopolize the primary template. The proper way to make hash_value work with sub_range<T>, as with any other type, is for sub_range to define a hash_value overload as an inline friend or in its namespace.