Re: GNAT: bug or feature?

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Damien Carbonne <damien.carbonne@free.fr> writes:

> Thanks (both of you) for explanations.
> Indeed, when no new component is added, it seems possible for the
> compiler to automatically generate the required function.

Exactly.  The compiler generates something like:

   overriding
   function Create return Derived is
   begin
      return (Base'(Create) with null record);
   end Create;

which just returns the same thing as the Base type's Create,
but with the Tag set properly for the Derived type.

By the way, you're slightly misusing the term "base" -- that's
not what it means in Ada.  You could call it Parent.  Or Root.

A "base subtype" is something else.

- Bob