[Ada] Spurious discriminant check on bounded synchronized queue

gcc/ada/

	* libgnat/a-cbsyqu.ads (Implementation): Provide a box
	initialization for the element array used internally to
	represent the queue, so that its components are properly
	initialized if the given element type has default
	initialization. Suppress warnings on the rest of the package in
	case the element type has no default or discriminant, because it
	is bound to be confusing to the user.

diff --git a/gcc/ada/libgnat/a-cbsyqu.ads b/gcc/ada/libgnat/a-cbsyqu.ads
index 225db2184086f0431341d93a06f02ea3900ea7d9..4037d84cb03479383ea64354e5068c0e94f8dc5d 100644 (file)
--- a/gcc/ada/libgnat/a-cbsyqu.ads
+++ b/gcc/ada/libgnat/a-cbsyqu.ads
@@ -71,6 +71,14 @@ is
 
       --  Need proper heap data structure here ???
 
+      --  We suppress warnings here, which might otherwise be triggered
+      --  by the box initialization of the Elements array below. This
+      --  initialization is needed to preserve constraints, such as
+      --  discriminant values, that the actual for Element_Type might
+      --  carry.
+
+      pragma Warnings (Off);
+
       type Element_Array is
         array (Count_Type range <>) of Queue_Interfaces.Element_Type;
 
@@ -78,7 +86,7 @@ is
          First, Last : Count_Type := 0;
          Length      : Count_Type := 0;
          Max_Length  : Count_Type := 0;
-         Elements    : Element_Array (1 .. Capacity);
+         Elements    : Element_Array (1 .. Capacity) := (others => <>);
       end record;
 
    end Implementation;