[Ada] Failure to detect redeclaration of constant with initial aggregate value

[Arnaud Charlet]

This patch fixes an omission in the detection of illegal redeclarations of
constants whose previous full declaration includes an expression that is an
aggregate.

Compiling double.adb must be rejected with:

   double.adb:5:04: "Data_1" conflicts with declaration at line 3

---
procedure Double is
   type Arr is array (1..10) of Integer;
   Data_1 : constant Arr := (1 => 1, others => 0);

   Data_1 : constant Arr := (others => 5);
begin
   null;
end;

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

2014-01-24  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch3.adb (Constant_Redeclaration): New declaration is
	illegal if previous one has an initial expression that is an
	aggregate expanded into assignments.

-------------- next part --------------
Index: sem_ch3.adb
===================================================================
--- sem_ch3.adb	(revision 207039)
+++ sem_ch3.adb	(working copy)
@@ -11104,10 +11104,13 @@
       --  If previous full declaration or a renaming declaration exists, or if
       --  a homograph is present, let Enter_Name handle it, either with an
       --  error or with the removal of an overridden implicit subprogram.
+      --  The previous one is a full declaration if it has an expression
+      --  (which in the case of an aggregate is indicated by the Init flag).
 
       if Ekind (Prev) /= E_Constant
         or else Nkind (Parent (Prev)) = N_Object_Renaming_Declaration
         or else Present (Expression (Parent (Prev)))
+        or else Has_Init_Expression (Parent (Prev))
         or else Present (Full_View (Prev))
       then
          Enter_Name (Id);