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=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: "Alejandro R. Mosteo" <alejandro@mosteo.com>
Newsgroups: comp.lang.ada
Subject: Generic private type declaration
Date: Fri, 25 Nov 2016 18:36:24 +0100
Organization: A noiseless patient Spider
Message-ID: <o19sod$ug2$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Fri, 25 Nov 2016 17:35:09 -0000 (UTC)
Injection-Info: mx02.eternal-september.org;
 posting-host="a0b82af40bbd0c9cd05c1ba8662dedd5";
	logging-data="31234"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX19ICHXJzEonm23b+mafhqo5"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
X-Mozilla-News-Host: news://news.eternal-september.org:119
Cancel-Lock: sha1:xLskohGdCXem58cTwaNgPSRQPCE=
Xref: news.eternal-september.org comp.lang.ada:32462
Date: 2016-11-25T18:36:24+01:00
List-Id: <comp.lang.ada>

Hello,

I need some eyes on this error because I'm missing something basic. When 
compiling this code:

procedure B001_Tagged is

    generic
       type X is private;
    package Untagged is

       type Y is new X;

    end Untagged;

    package Ok is new Untagged (Integer);

    type Void is tagged null record;

    package Err is new Untagged (Void); --  Error here

begin
    null;
end B001_Tagged;

I get in both gnat 4.9.3 and gpl2016 the following error:

b001_tagged.adb:15:04: instantiation error at line 7
b001_tagged.adb:15:04: type derived from tagged type must have extension
gnatmake: "b001_tagged.adb" compilation error

I would expect that the view inside the generic package is untagged and 
so the type renaming in line 7 should be correct? Or I'm floundering 
with the generic parameter declaration?

Thanks,
Alex.