Variadic template alias parameters

[Dylan Knutson]

Hello!
As far as I can tell, you can't have a variadic of alias 
parameters on a template, which is strange to me. Eg, you can't 
do something like:

template Foo(alias Args...) {
  ...
}

int i = 0;
Foo!(std.conv, "123", i);

Is there a reason for this restriction?