1 files changed, 39 insertions, 13 deletions

diff --git a/gcc/ada/a-cidlli.adb b/gcc/ada/a-cidlli.adb
index bad5a896455..183f6a8614a 100644
--- a/gcc/ada/a-cidlli.adb
+++ b/gcc/ada/a-cidlli.adb
@@ -242,6 +242,33 @@ package body Ada.Containers.Indefinite_Doubly_Linked_Lists is
       Free (X);
    end Clear;
 
+   ------------------------
+   -- Constant_Reference --
+   ------------------------
+
+   function Constant_Reference
+     (Container : aliased List;
+      Position  : Cursor) return Constant_Reference_Type
+   is
+   begin
+      if Position.Container = null then
+         raise Constraint_Error with "Position cursor has no element";
+      end if;
+
+      if Position.Container /= Container'Unrestricted_Access then
+         raise Program_Error with
+           "Position cursor designates wrong container";
+      end if;
+
+      if Position.Node.Element = null then
+         raise Program_Error with "Node has no element";
+      end if;
+
+      pragma Assert (Vet (Position), "bad cursor in Constant_Reference");
+
+      return (Element => Position.Node.Element.all'Access);
+   end Constant_Reference;
+
    --------------
    -- Contains --
    --------------
@@ -1303,27 +1330,26 @@ package body Ada.Containers.Indefinite_Doubly_Linked_Lists is
    -- Reference --
    ---------------
 
-   function Constant_Reference (Container : List; Position : Cursor)
-   return Constant_Reference_Type is
+   function Reference
+     (Container : aliased in out List;
+      Position  : Cursor) return Reference_Type
+   is
    begin
-      pragma Unreferenced (Container);
-
       if Position.Container = null then
          raise Constraint_Error with "Position cursor has no element";
       end if;
 
-      return (Element => Position.Node.Element.all'Access);
-   end Constant_Reference;
-
-   function Reference (Container : List; Position : Cursor)
-   return Reference_Type is
-   begin
-      pragma Unreferenced (Container);
+      if Position.Container /= Container'Unrestricted_Access then
+         raise Program_Error with
+           "Position cursor designates wrong container";
+      end if;
 
-      if Position.Container = null then
-         raise Constraint_Error with "Position cursor has no element";
+      if Position.Node.Element = null then
+         raise Program_Error with "Node has no element";
       end if;
 
+      pragma Assert (Vet (Position), "bad cursor in function Reference");
+
       return (Element => Position.Node.Element.all'Access);
    end Reference;