Re: changing rules for anonymous access types to named ones

[Jere <jhb.chat@gmail.com>]

On Monday, April 2, 2018 at 12:39:38 PM UTC-4, Jean-Claude Rostaing wrote:
> Hi.
> There's definitely a change in rules from 95 to 2012 I spotted, which makes things more ugly:
> that: Set(new Plus_Operator);
> was written for ada95. Now, it gives the error:
> expected type "TOKEN_ACCESS" defined at expressions.ads:22
> found type access to "Plus_Operator" defined at line 48
> TOKEN_ACCESS is merely a named access type to TOKEN_TYPE'class, which PLUS_OPERATOR is a child of.
> 
> I made a compilable exemple of my case:
> 
> with ada.Text_IO;
> use ada.Text_IO;
> procedure ESSAI is
>    type A is abstract tagged limited null record;
>    type A_Child is new A with null record;
>    type pointers_A is access A'CLASS;
>    type B is interface;
>    type B_child is new B with null record;
>    type pointers_B is access b'CLASS;
>    function F1 (obj: pointers_A) return INTEGER is (1);
>    function F2 (obj: pointers_b) return INTEGER IS (1);
> begin
>    PUT_LINE("avec abstract tagged null record : " & INTEGER'IMAGE(F1(new A_child));
>    Put_Line("AVEC interface : " & INTEGER'IMAGE(F2(new B_child));
> end;
> 
> Only the second statement fails. I could find nothing in the access type section related to interface nor the reciprocal so I'm sure it's not normal.

I don't think interfaces were part of 95 and they may have different rules 
versus an abstract record.  However, you can change your access type to a
general access type to solve the compilation error:

 type pointers_B is access all b'CLASS;