styleg-c.ads, [...] (Missing_Overriding): new procedure to implement style check that overriding operations are...

2008-08-20  Ed Schonberg  <schonberg@adacore.com>

	* styleg-c.ads, styleg-c.adb (Missing_Overriding): new procedure to
	implement style check that overriding operations are explicitly marked
	at such.

	* style.ads (Missing_Overriding): new procedure that provides interface
	to previous one.

	* stylesw.ads, stylesw.adb: New style switch -gnatyO, to enable check
	that the declaration or body of overriding operations carries an
	explicit overriding indicator.

	* sem_ch8.adb
	(Analyze_Subprogram_Renaming): if operation is overriding, check whether
	explicit indicator should be present.

	* sem_ch6.adb (Verify_Overriding_Indicator,
	Check_Overriding_Indicator): If operation is overriding, check whether
	declaration and/or body of subprogram should be present

From-SVN: r139316

1 files changed, 24 insertions, 7 deletions

diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
index 1100c30..23de8b6 100644
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -1724,6 +1724,12 @@ package body Sem_Ch6 is
                 "if subprogram is primitive",
                 Body_Spec);
             end if;
+
+         elsif Style_Check
+           and then Is_Overriding_Operation (Spec_Id)
+         then
+            pragma Assert (Unit_Declaration_Node (Body_Id) = N);
+            Style.Missing_Overriding (N, Body_Id);
          end if;
       end Verify_Overriding_Indicator;
 
@@ -4167,6 +4173,10 @@ package body Sem_Ch6 is
             Set_Is_Overriding_Operation (Subp);
          end if;
 
+         if Style_Check and then not Must_Override (Spec) then
+            Style.Missing_Overriding (Decl, Subp);
+         end if;
+
       --  If Subp is an operator, it may override a predefined operation.
       --  In that case overridden_subp is empty because of our implicit
       --  representation for predefined operators. We have to check whether the
@@ -4190,16 +4200,23 @@ package body Sem_Ch6 is
                  ("subprogram & overrides predefined operator ", Spec, Subp);
             end if;
 
-         elsif Is_Overriding_Operation (Subp) then
-            null;
-
          elsif Must_Override (Spec) then
-            if not Operator_Matches_Spec (Subp, Subp) then
-               Error_Msg_NE ("subprogram & is not overriding", Spec, Subp);
-
-            else
+            if Is_Overriding_Operation (Subp) then
                Set_Is_Overriding_Operation (Subp);
+
+            elsif not Operator_Matches_Spec (Subp, Subp) then
+               Error_Msg_NE ("subprogram & is not overriding", Spec, Subp);
             end if;
+
+         elsif not Error_Posted (Subp)
+           and then Style_Check
+           and then Operator_Matches_Spec (Subp, Subp)
+             and then
+               not Is_Predefined_File_Name
+                 (Unit_File_Name (Get_Source_Unit (Subp)))
+         then
+            Set_Is_Overriding_Operation (Subp);
+            Style.Missing_Overriding (Decl, Subp);
          end if;
 
       elsif Must_Override (Spec) then