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From: Victor Porton <porton@narod.ru>
Newsgroups: comp.lang.ada
Subject: Re: Is Adjust allowed on assignment of to a class-wide argument?
Date: Fri, 29 Sep 2017 19:43:17 +0300
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Date: 2017-09-29T19:43:17+03:00
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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