Allowing "fall through" of attributes

[Rufus Smith via Digitalmars-d-learn]

I have some functions that take other functions. I would like the 
attributes to be able to "fall" through so I get overload like 
behavior. I only care that I am passing a function, not if it is 
shared, extern(C), pure, @nogc, etc.

void foo(R, A...)(R function(A) bar)
{
    alias type = typeof(bar);
    pragma(msg, type);
    // does magic with bar
}

foo never uses the attributes of bar explicitly. It uses type to 
instantiate other functions like bar. I have to create a foo for 
each attribute combination, which is not worth while. The code 
seems to break only for extern, the best I can tell, most 
attributes do pass through. But type does not contain these 
attributes.