child packages and nested packages

[okellogg@freenet.de (Oliver Kellogg)]

Hello CLA,

How come child packages are only possible for library level packages?

I now encountered a situation where I'd like to create a child 
package of a nested package:

-- file: pkg.ads
package Pkg is
   package Nested is
      type Object is tagged null record;
   end Nested;
end Pkg;

-- file: pkg-nested-child.ads
package Pkg.Nested.Child is
   type Derived is new Object with null record;
end Pkg.Nested.Child;


(The only thing that crosses my naive mind is that this makes 
life harder for the Ada compiler in that if a file pkg-nested.ads 
cannot be found then the compiler would need to look inside pkg.ads 
to see if the parent to which the child refers can be found there.)

Thanks,

O. Kellogg