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,FREEMAIL_FROM
	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!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail
From: Victor Porton <porton@narod.ru>
Newsgroups: comp.lang.ada
Subject: Re: "use" after "limited with" (GNAT bug?)
Date: Thu, 14 Aug 2014 21:41:42 +0300
Organization: Aioe.org NNTP Server
Message-ID: <lsivt6$ecc$1@speranza.aioe.org>
References: <lsitvc$9l8$1@speranza.aioe.org>
 <f03ffc27-3d37-4af0-b8c3-9f4bc07cc6ee@googlegroups.com>
NNTP-Posting-Host: AnnUDmZwVERVUXyHDyOl5A.user.speranza.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7Bit
X-Complaints-To: abuse@aioe.org
User-Agent: KNode/4.12.4
X-Notice: Filtered by postfilter v. 0.8.2
Xref: news.eternal-september.org comp.lang.ada:21771
Date: 2014-08-14T21:41:42+03:00
List-Id: <comp.lang.ada>

Adam Beneschan wrote:

> On Thursday, August 14, 2014 11:08:47 AM UTC-7, Victor Porton wrote:
>> -- p1.ads
>> 
>> package P1 is
>> 
>> end P1;
>> 
>> -- p2.ads
>> 
>> limited with P1;
>> use P1;
>> 
>> package P2 is
>> 
>> end P2;
>> 
>> 
>> 
>> $ gnatmake -q -c -gnatc -u -P/home/porton/t/p/default.gpr p2.ads
>> p2.ads:2:05: "P1" is undefined
>> gnatmake: "/home/porton/t/p/p2.ads" compilation error
>> 
>> Why "use" does not work? Is it a bug of gnatgcc (Debian 4.9.1-4) 4.9.1?
> 
> It's illegal.  You just can't USE a LIMITED WITH'ed package.
> 
> RM 10.1.2, paragraphs 19, 22:
> 
> A limited_with_clause that names a library package shall not appear:
> 
> within a context_clause for a library_item that is within the scope of a
> use_clause that names an entity declared within the declarative region of
> the library package.
> 
> From the AARM:
> 
> Reason: This prevents visibility issues, where whether an entity is an
> incomplete or full view depends on how the name of the entity is written.
> The limited_with_clause cannot be useful, as we must have the full view
> available in the parent in order for the use_clause to be legal.

Not a language lawyer, but may be it makes sense to introduced "limited use" 
clauses?

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