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

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

[Victor Porton]

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

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

[Victor Porton]

Victor Porton wrote:

> 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;

I think, it is not allowed because A'Class is a by-reference type.

But I am not 100% sure.

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

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

[AdaMagica]

Am Freitag, 29. September 2017 18:43:19 UTC+2 schrieb Victor Porton:
> I think, it is not allowed because A'Class is a by-reference type.

All tagged types are by reference.
Why do you think Adjust should be called. There is no assignment in your code?
See:
http://www.christ-usch-grein.homepage.t-online.de/AdaMagica/Secretive.html