[Ada] Crash on illegal selected component in synchronized body.

[Arnaud Charlet <charlet at adacore dot com>]

The prefix of a selected component in a synchronized body cannot denote
a component of the synchronized type unless the prefix is an entity name.
This was not properly rejected before.

Compiling bakery.adb must yield:

bakery.adb:44:35: invalid reference to internal operation of some object
   of type "Bakery_Instance_Task"

---
procedure Bakery is

   N        : Natural := 10; -- Number of Processes [Customers]

   type Integer_Array is array (1 .. N) of Integer;

   type Ticket_And_Queue_Number is record
      R : Natural; -- Ticket Number [Lamport 'Number']
      A : Natural; -- Queue Number  [Lamport 'Choosing']
   end record;

   task type Bakery_Instance_Task is
      entry Initialize(ID : Natural);
   end Bakery_Instance_Task;

   Bakery_Array : array (1 .. N) of Bakery_Instance_Task;

   task body Bakery_Instance_Task is

      R   : Natural; -- This task's current ticket number [Lamport 'Number']
      A   : Integer_Array := (1 .. N => 0);
      ID0 : Natural;

      TQN : Ticket_And_Queue_Number;

      function Read_TQN(J : in     Natural) return Ticket_And_Queue_Number is
         TQN : Ticket_And_Queue_Number;
      begin
         TQN := (R => R,
                 A => A(J));
         return TQN;
      end Read_TQN;
   begin
      accept Initialize(ID : Natural) do
         R := 0;
         A := (1 .. N => 0);
         ID0 := ID;
      end Initialize;
      -- Start
      R := 1;
      A(ID0) := 1;
      for J in 1 .. N loop
         if J /= ID0 then
            TQN := Bakery_Array(J).Read_TQN(J => J);
         end if;
      end loop;
   end Bakery_Instance_Task;

begin
   for I in 1 .. N loop
      Bakery_Array(I).Initialize(ID => I);
   end loop;
end Bakery;

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

2015-11-12  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch4.adb (Analyze_Selected_Component): Diagnose an attempt
	to reference an internal entity from a synchronized type from
	within the body of that type, when the prefix of the selected
	component is not the current instance.

Attachment: difs
Description: Text document