Accessibility Levels and Library-Level Units

[Eryndlia Mavourneen <eryndlia@gmail.com>]

I have a package that defines a single procedure access type:

   1. package Accessibility_Level_Def is
   2.   pragma Pure;
   3.   type Proc_Type is access procedure (An_Str : String);
   4. end Accessibility_Level_Def;

I have a main program which references it (and another package):

    1. with Ada.Text_IO;                        use Ada.Text_IO;
    2. with Accessibility_Level_Def;            use Accessibility_Level_Def;
    3. with Accessibility_Level_Implementation; use Accessibility_Level_Implementation;
    4. procedure Accessibility_Level_Test is
    5.    procedure Test (Text : String);
    6.    procedure Test (Text : String) is
    7.    begin
    8.       Put_Line ("in Test");
    9.    end Test;
   10. 
   11.    The_Proc : Proc_Type;
   12. begin
   13.    The_Proc := Test'Access;
   14.    Sub (Proc => The_Proc);
   15. end Accessibility_Level_Test;

Gnat 2012 (on Ubuntu) gives the error on line 13:

   "Subprogram must not be deeper than access type."

I thought I understood accessibility levels, at least, I understood the examples I have found.  Yet, this example appears to not have the same issues:

1) All the units -- packages and procedure -- are at library level.
2) The procedure is statically defined and is not going to be 
   deallocated until the program exits.

This is very frustrating and would seem to preclude the definition of a procedural access type in a separate definitions package.  The Implementation package (defining procedure Sub but not shown) compiles nicely, btw.

Is this a problem with Gnat?  If not, how can I do what I want to do?  The attribute Unchecked_Access is not available for subprogram access types.

-- Eryndlia (KK1T)