From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,af3dada69080e420
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-06-24 05:20:03 PST
Path: 
 archiver1.google.com!news1.google.com!sn-xit-02!sn-xit-03!sn-xit-01!sn-xit-08!supernews.com!news.tele.dk!news.tele.dk!small.news.tele.dk!news-fra1.dfn.de!news-koe1.dfn.de!RRZ.Uni-Koeln.DE!uni-duisburg.de!not-for-mail
From: Georg Bauhaus <sb463ba@d2-hrz.uni-duisburg.de>
Newsgroups: comp.lang.ada
Subject: Re: Interesting effects in array renaming
Date: Tue, 24 Jun 2003 11:53:21 +0000 (UTC)
Organization: GMUGHDU
Message-ID: <bd9e3h$sc$1@a1-hrz.uni-duisburg.de>
References: <bd4fmr$p4kfn$1@ID-77047.news.dfncis.de>
 <3EF5E6B8.3030203@spam.com> <bd6ckc$p8kv1$1@ID-77047.news.dfncis.de>
 <3EF7B8CC.3000100@attbi.com> <bd8uqg$q0jfa$2@ID-77047.news.dfncis.de>
NNTP-Posting-Host: d2-hrz.uni-duisburg.de
X-Trace: a1-hrz.uni-duisburg.de 1056455601 908 134.91.1.15 (24 Jun 2003
 11:53:21 GMT)
X-Complaints-To: usenet@news.uni-duisburg.de
NNTP-Posting-Date: Tue, 24 Jun 2003 11:53:21 +0000 (UTC)
User-Agent: tin/1.5.8-20010221 ("Blue Water") (UNIX) (HP-UX/B.11.00
 (9000/831))
Xref: archiver1.google.com comp.lang.ada:39654
Date: 2003-06-24T11:53:21+00:00
List-Id: <comp.lang.ada>

Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> wrote:
: That the new view is wellcome to be inconsistent does not follow from that. 
: It is written pair lines below. BTW, for tagged types it is different and 
: semantically consistent:
: 
: procedure Foo (X : Base'Class) is
:   XX : Derived renames X;           -- Illegal
:   XX : Derived renames Derived (X); -- Legal and *CHECKED*

I'm not sure, considering

   procedure Foo (X : in out Varying'Class) is
      subtype Nono is Changeant (false);
      X1 : Changeant renames X;           -- Illegal
      X2 : Nono renames Changeant(X); -- Legal and *CHECKED*
   begin
      X2.messy := 2 * X2.messy; 
	-- constraint_error when discriminant is true
   end Foo;
 
where
package Derivs is

   type Varying (special: Boolean)
   is
     tagged record
        comp: Natural;
     end record;


   type Changeant (very_special: Boolean)
   is
     new Varying(very_special) with
      record
         case very_special is
            when true =>
               another: Boolean;
            when false =>
               messy: Integer;
         end case;
      end record;


end Derivs;


-- Georg