gcc/testsuite/gnat.dg/abstract1.adb

   1 --  { dg-do compile }
   2 with Ada.Tags.Generic_Dispatching_Constructor;  use Ada.Tags;
   3 package body abstract1 is
   4
   5    function New_T (Stream : not null access Root_Stream_Type'Class)
   6       return T'Class is
   7       function Construct is
   8          new Generic_Dispatching_Constructor (T, Root_Stream_Type'Class, Input);
   9       E : constant String := String'Input (Stream);
  10       I : constant Tag := Internal_Tag (E);
  11
  12    begin
  13       return Construct (I, Stream);
  14    end New_T;
  15
  16    function Input (Stream : not null access Root_Stream_Type'Class)
  17      return IT is
  18    begin
  19       return O : IT do
  20         Integer'Read (Stream, O.I);
  21       end return;
  22    end Input;
  23
  24    function Input (Stream : not null access Root_Stream_Type'Class)
  25       return FT is
  26    begin
  27       return O : FT do
  28         Float'Read (Stream, O.F);
  29       end return;
  30    end Input;
  31 end abstract1;