From patchwork Thu Jun 17 15:24:44 2010
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Subject: [Ada] Freezing the designated type of an access_to_subprogram_type
Date: Thu, 17 Jun 2010 05:24:44 -0000
From: Arnaud Charlet <charlet@adacore.com>
X-Patchwork-Id: 56061
Message-Id: <20100617152444.GA14164@adacore.com>
To: gcc-patches@gcc.gnu.org
Cc: Ed Schonberg <schonberg@adacore.com>

A type cannot be frozen if it is not yet fully defined. For the designated
type of an access_to_subprogram_type, all the types in its profile must be
fully defined before the subprogram type itself can be frozen.

The following must compile quietly:

---
with Statefull_Artifact_G;
procedure Main is
   type State is (CREATED, REVIEWED);
   type Activity is (REVIEW);

   package Requirement is
        new Statefull_Artifact_G (State, Activity, State'First);
begin
   null;
end Main;
---
with Ada.Finalization;
generic
   type State is (<>);
   type Activity is (<>);
   Initial_State : State := State'First;
package Statefull_Artifact_G is

   type Statefull_Artifact is
      abstract new Ada.Finalization.Controlled with private;

   type Guard is access function (This : Statefull_Artifact'Class)
                                  return Boolean;
private
   type State_Ref is access all State;
   type Guard_Map is array (State, Activity) of Guard;
   Guards : Guard_Map := (others => (others => null));

   type Statefull_Artifact is
      abstract new Ada.Finalization.Controlled with record
      Current_State : State_Ref := null;
   end record;
end Statefull_Artifact_G;

Tested on x86_64-pc-linux-gnu, committed on trunk

2010-06-17  Ed Schonberg  <schonberg@adacore.com>

	* freeze.adb (Freeze_Expression): The designated type of an
	access_to_suprogram type can only be frozen if all types in its profile
	are fully defined.

Index: freeze.adb
===================================================================
--- freeze.adb	(revision 160905)
+++ freeze.adb	(working copy)
@@ -5306,6 +5306,26 @@ package body Freeze is
             return True;
          end;
 
+      --  For the designated type of an access to subprogram. all types in
+      --  the profile must be fully defined.
+
+      elsif Ekind (T) = E_Subprogram_Type then
+         declare
+            F : Entity_Id;
+
+         begin
+            F := First_Formal (T);
+            while Present (F) loop
+               if not Is_Fully_Defined (Etype (F)) then
+                  return False;
+               end if;
+
+               Next_Formal (F);
+            end loop;
+
+            return Is_Fully_Defined (Etype (T));
+         end;
+
       else
          return not Is_Private_Type (T)
            or else Present (Full_View (Base_Type (T)));