array of functions/delegates

[Rumbu via Digitalmars-d-learn]

I am trying to create an array of functions inside a struct.
struct S {
  void f1() {}
  void f2() {}

  alias Func = void function();

 immutable Func[2] = [&f1, &f2]

}

What I got: Error: non-constant expression '&f1'

Tried also with delegates (since I am in a struct context but I 
got: no `this` to create delegate `f1`.

So, is there any way to have an array of functions without adding 
them at runtime?