Is Adjust allowed on assignment of to a class-wide argument?

[Victor Porton <porton@narod.ru>]

Is the following program allowed to print "Adjust"?

GCC 7.2.0 does not print "Adjust". I suspect it is because GCC optimizes 
away an allowed Adjust procedure.

Is it allowed to call Adjust? Will a compiler be conforming to the spec if 
it produces from the below source a program which prints "Adjust"?

---------------
with Ada.Finalization;
with Ada.Text_IO;

procedure Test is

  type A is new Ada.Finalization.Controlled with null record;

  type B is new A with null record;

  overriding procedure Adjust (Object: in out B) is
  begin
    Ada.Text_IO.Put_Line("Adjust");
  end;

  procedure X (Arg: A'Class) is
  begin
    null;
  end;

  Object: B;

begin
  X(Object);
end;

-- 
Victor Porton - http://portonvictor.org