No warning given for uninitialized volatile variable

volatile_package.ads:

package Volatile_Package with SPARK_Mode => On
is

   type Index_Type is range 192 .. 210; -- Some small, arbitrary range

   Package_Variable : Index_Type with Volatile;

end Volatile_Package;

volatile_uninit.adb:

with Ada.Text_IO;
with Volatile_Package;

procedure Volatile_Uninit with SPARK_Mode => On
is

   type Array_Type is array (Volatile_Package.Index_Type) of Integer;

   Local_Array : constant Array_Type := (others => 15); -- Some arbitrary value

   Local_Index_Variable : Volatile_Package.Index_Type;

   Local_Integer : Integer;
   
begin
   Local_Index_Variable := Volatile_Package.Package_Variable;
   Local_Integer := Local_Array (Local_Index_Variable);
   Ada.Text_IO.Put_Line ("Value of Local_Integer: " & Local_Integer'Image);
end Volatile_Uninit;

Running Spark:

alr gnatprove --assumptions 

on the above code does not give any warning nor state in gnatprove.out that Volatile_Package.Package_Variable is assumed to be initialized. If I understand, Spark makes this assumption due to Async_Writers being implicitly true for Package_Variable and Spark RM 7.1.2 Rule 14 applying.

I would have expected Spark to warn that it is making this assumption to alert the user and prompt manual review, since incorrect usage can lead to undefined behavior/erroneous execution as in the case above:

alr build --release
alr run

Garbage output:

Value of Local_Integer:  1413566023

Versions:
gnat FSF: 14.2.1
gnatprove: 14.1.1

Start by reproducing the case in volatile_package.ads and volatile_uninit.adb with gnatprove --assumptions, then inspect gnatprove.out for the missing initialization warning. Review the stated interaction between Async_Writers and Spark RM 7.1.2 Rule 14. Done means the tool clearly reports when it assumes Package_Variable is initialized, with appropriate coverage for this example.