Getting the template name of a template instantiation

[John via Digitalmars-d-learn]

On Monday, 27 June 2016 at 16:40:09 UTC, Nordlöw wrote:
> If I have a template parameter
>
>     E = S!int
>
> where
>
>     struct S(T) { S x; }
>
> how can I extract the template name part `S` from E`?
>
> Something like:
>
>     static assert(is(templateName!(S!int) == S));
>
> Is this already in Phobos somewhere?

import std.traits;
__traits(identifier, TemplateOf!(S!int));