sem_ch11.adb: Improved warnings for unused variables

2007-08-14  Robert Dewar  <dewar@adacore.com>
	    Ed Schonberg  <schonberg@adacore.com>

	* sem_ch11.adb: Improved warnings for unused variables

	* sem_ch3.ads, sem_ch3.adb (Build_Derived_Record_Type): If the ancestor
	is a synchronized interface, the derived type is limited.
	(Analyze_Object_Declaration): Mark the potential coextensions in the
	definition and expression of an object declaration node.
	(Build_Derived_Type): For the completion of a private type declaration
	with a derived type declaration, chain the parent type's representation
	items to the last representation item of the derived type (not the
	first one) if they are not present already.
	(Analyze_Object_Declaration, Constant_Redeclaration): Allow incomplete
	object declaration of forward references to tags.
	(Access_Subprogram_Declaration): In Ada2005, anonymous access to
	subprogram types can appear as access discriminants of synchronized
	types.
	(OK_For_Limited_Init_In_05): The initialization is legal is it is a call
	given in prefixed form as a selected component.
	(Process_Discriminants): If not all discriminants have defaults, place
	error message on a default that is present.
	(Analyze_Private_Extension_Declaration): Diagnose properly an attempt to
	extend a synchronized tagged type.
	Improved warnings for unused variables
	(Is_Visible_Component): Fix a visibility hole on a component inherited
	by a private extension when parent is itself declared as a private
	extension, and the derivation is in a child unit.
	(Find_Hidden_Interface): Move spec from the package body.

From-SVN: r127426

gcc/ada/sem_ch11.adb

@@ -225,9 +225,11 @@ package body Sem_Ch11 is
 
                Generate_Definition (Choice);
 
-               --  Set source assigned flag, since in effect this field is
-               --  always assigned an initial value by the exception.
+               --  Indicate that choice has an initial value, since in effect
+               --  this field is assigned an initial value by the exception.
+               --  We also consider that it is modified in the source.
 
+               Set_Has_Initial_Value (Choice, True);
                Set_Never_Set_In_Source (Choice, False);
             end if;
 
@@ -269,7 +271,7 @@ package body Sem_Ch11 is
                            if Warn_On_Obsolescent_Feature then
                               Error_Msg_N
                                 ("Numeric_Error is an " &
-                                 "obsolescent feature ('R'M 'J.6(1))?", Id);
+                                 "obsolescent feature (RM J.6(1))?", Id);
                               Error_Msg_N
                                 ("\use Constraint_Error instead?", Id);
                            end if;
@@ -306,7 +308,7 @@ package body Sem_Ch11 is
                                  "generic formal package", Id, Ent);
                               Error_Msg_N
                                 ("\and therefore cannot appear in " &
-                                 "handler ('R'M 11.2(8))", Id);
+                                 "handler (RM 11.2(8))", Id);
                               exit;
 
                            --  If the exception is declared in an inner
@@ -462,7 +464,7 @@ package body Sem_Ch11 is
                       P);
                   Error_Msg_N
                     ("\?RAISE statement may result in abnormal return" &
-                     " ('R'M 6.4.1(17))", P);
+                     " (RM 6.4.1(17))", P);
                end if;
             end if;
          end;

gcc/ada/sem_ch3.ads

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2006, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2007, 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- --
@@ -137,6 +137,13 @@ package Sem_Ch3  is
    --  Note: one might expect this to be private to the package body, but
    --  there is one rather unusual usage in package Exp_Dist.
 
+   function Find_Hidden_Interface
+     (Src  : Elist_Id;
+      Dest : Elist_Id) return Entity_Id;
+   --  Ada 2005: Determine whether the interfaces in list Src are all present
+   --  in the list Dest. Return the first differing interface, or Empty
+   --  otherwise.
+
    function Find_Type_Of_Subtype_Indic (S : Node_Id) return Entity_Id;
    --  Given a subtype indication S (which is really an N_Subtype_Indication
    --  node or a plain N_Identifier), find the type of the subtype mark.