check instance of nested variadic template

[Basile B. via Digitalmars-d-learn]

On Saturday, 5 November 2016 at 13:34:51 UTC, Gianni Pisetta 
wrote:
> When i have time i will test it with ldc and see if the result 
> is the same, then it will probably be a front-end bug and i 
> will report it as an issue.

Indeed, I've been fighting against that since a few minutes. We 
cant select the Base of an eponymous template.


template isEponymousTemplate(T)
{
     static if (is(T == class) || is(T == interface) || is(T == 
struct) || is(T == union))
     {
         enum p = __traits(parent, T).stringof == T.stringof;
         enum isEponymousTemplate = p && isTemplateInstance!T;
     }
     else
         enum isEponymousTemplate = false;
}

template TemplateBase(T : Base!Args, alias Base, Args...)
if (is(T == class) || is(T == interface) || is(T == struct) || 
is(T == union))
{
     alias TemplateBase = Base;
}