A function that cannot be called?

["G.B." <bauhaus@notmyhomepage.invalid>]

There is a type declaration, I rememberd, in Ada, that
does not allow any object of the type to be declared.
I think the type should be along the lines below. Is
this correct?

Then, a function that nominally returns objects of
this type should be impossible to call. Is this right,
too?

generic
     type T(<>) is limited private;  -- gen. arg. type

package What is

     type Void (<>) is private;

     function Impossible (X : T) return Void;

private

     package Inner is
         type Void (<>) is private;
     private
         type Void is  record
             null;
         end record;
     end Inner;

     type Void is new Inner.Void;

end What;

(If current Ada could still pass by reference in both call
direction and return direction, then I'd have added *limited*
to the Voids' declarations. Without it, a body of Impossible
is closer to becoming possible by using Convention => Ada
together with an 'Address clause on a Result object. I think.)