Re: Erroneous "auto can only be used for template function parameters"?

[Yuxuan Shui via Digitalmars-d-learn]

On Sunday, 21 June 2015 at 01:26:51 UTC, Adam D. Ruppe wrote:
On Saturday, 20 June 2015 at 01:50:11 UTC, Yuxuan Shui wrote:
auto ref R) is indeed a template function, so I don't 
understand.

But R is not a parameter on the function itself. It comes from 
the outside template.

Move it to the inside template, rewrite it as:

        auto a(S, R)(auto ref R i) {
                return cast(S)i*2;
        }

and you should get further.

But surely nested template should be able to access outer 
template's parameter.