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-Thread: a07f3367d7,f857f366542cd8aa
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news2.google.com!npeer01.iad.highwinds-media.com!feed-me.highwinds-media.com!cyclone01.ams2.highwinds-media.com!news.highwinds-media.com!npeersf01.ams.highwinds-media.com!newsfe12.ams2.POSTED!7564ea0f!not-for-mail
From: Chris Moore <zmower@ntlworld.com>
User-Agent: Thunderbird 2.0.0.22 (Windows/20090605)
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Subject: Re: Dispatch on the result still does not work?
References: <ubjkmle9n5pi.1ovhyam5f9lf5$.dlg@40tude.net>
 <Rp_5m.72048$HE6.53928@newsfe27.ams2>
 <1c6l5llyivd71.9dw3tmgglnlv.dlg@40tude.net>
In-Reply-To: <1c6l5llyivd71.9dw3tmgglnlv.dlg@40tude.net>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Message-ID: <xh46m.85371$%Q1.20406@newsfe12.ams2>
NNTP-Posting-Host: 82.18.136.180
X-Complaints-To: http://netreport.virginmedia.com
X-Trace: newsfe12.ams2 1247334621 82.18.136.180 (Sat,
 11 Jul 2009 17:50:21 UTC)
NNTP-Posting-Date: Sat, 11 Jul 2009 17:50:21 UTC
Organization: virginmedia.com
Date: Sat, 11 Jul 2009 18:50:42 +0100
Xref: g2news2.google.com comp.lang.ada:6992
Date: 2009-07-11T18:50:42+01:00
List-Id: <comp.lang.ada>

Dmitry A. Kazakov wrote:
> On Sat, 11 Jul 2009 12:09:57 +0100, Chris Moore wrote:
> 
>> Dmitry A. Kazakov wrote:
>>> Considering this one:
>>>
>>> package P is
>>>    type T is tagged null record;
>>>    function Value return T;
>>>       
>>>    type S is new T with null record;
>>>    function Value return S;
>>> end P;
>>>       
>>> package body P is
>>>    function Value return T is
>>>    begin
>>>       return (null record);
>>>    end Value;
>>>       
>>>    function Value return S is
>>>    begin
>>>       return (T with null record);
>>>    end Value;
>>> end P;
>>>
>>> use P;
>>>    
>>>    X : T'Class := S'(Value);
>>> begin
>>>    X := Value; -- Ambiguous?
>>>
>>> I would expect it rather dispatching on the tag of X, i.e. selecting Value,
>>> which returns S.
>>>
>> But X is of type T'Class.  Or did you mean X := X.Value;?
> 
> No. I meant function Value that has no arguments.

Then both versions of Value are in scope and return types that can be
assigned to T'Class.  Sounds ambiguous to me.

X := S'(Value);?