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From: Robert_Matthews <ignored@ramatthews.free-online.co.uk>
Subject: Another problem with "interface"
Date: Mon, 16 Feb 2009 09:53:59 +0000
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Date: 2009-02-16T09:53:59+00:00
List-Id: <comp.lang.ada>

In using interface types with GNAT I have encountered another problem.
Consider the following package:

package Test is

   type A_Type is limited interface;

   procedure P (A : in out A_Type; D : Integer) is abstract;

   protected type New_A_Type is new A_Type
   with
      procedure P (D : Integer);
      --  other subprograms...
   private
      F : Integer;
   end New_A_Type;

   function Set_A return New_A_Type;

end Test;

GNAT gives an error for the function Set_A: 
"operation can be dispatching in only one type",
which leaves me mystified. Am I making another
dumb mistake? Please help!

The version of GNAT is GNAT GPL 2008 (20080521).

Thanks in advance,

Robert