exp_intr.adb (Expand_Unc_Conversion): As a target type...

2005-03-08  Ed Schonberg  <schonberg@adacore.com>

	* exp_intr.adb (Expand_Unc_Conversion): As a target type, use the type
	that appears in the instantiation rather than the internal subtype
	generated in the wrapper package, to avoid anomalies in gigi when the
	target is derived from a private type whose full view is an access type.

From-SVN: r96495

gcc/ada/exp_intr.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2004 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2005 Free Software Foundation, Inc.          --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -479,6 +479,7 @@ package body Exp_Intr is
       Func : constant Entity_Id  := Entity (Name (N));
       Conv : Node_Id;
       Ftyp : Entity_Id;
+      Ttyp : Entity_Id;
 
    begin
       --  Rewrite as unchecked conversion node. Note that we must convert
@@ -500,12 +501,33 @@ package body Exp_Intr is
          Analyze_And_Resolve (Conv);
       end if;
 
+      --  The instantiation of Unchecked_Conversion creates a wrapper package,
+      --  and the target type is declared as a subtype of the actual. Recover
+      --  the actual, which is the subtype indic. in the subtype declaration
+      --  for the target type. This is semantically correct, and avoids
+      --  anomalies with access subtypes. For entities, leave type as is.
+
       --  We do the analysis here, because we do not want the compiler
       --  to try to optimize or otherwise reorganize the unchecked
       --  conversion node.
 
-      Rewrite (N, Unchecked_Convert_To (Etype (E), Conv));
-      Set_Etype (N, Etype (E));
+      Ttyp := Etype (E);
+
+      if Is_Entity_Name (Conv) then
+         null;
+
+      elsif Nkind (Parent (Ttyp)) = N_Subtype_Declaration then
+         Ttyp := Entity (Subtype_Indication (Parent (Etype (E))));
+
+      elsif Is_Itype (Ttyp) then
+         Ttyp :=
+           Entity (Subtype_Indication (Associated_Node_For_Itype (Ttyp)));
+      else
+         raise Program_Error;
+      end if;
+
+      Rewrite (N, Unchecked_Convert_To (Ttyp, Conv));
+      Set_Etype (N, Ttyp);
       Set_Analyzed (N);
 
       if Nkind (N) = N_Unchecked_Type_Conversion then