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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada.Containers.Indefinite_Holders in GNAT and Ada2012
Date: Mon, 11 Aug 2014 18:58:42 -0500
Organization: Jacob Sparre Andersen Research & Innovation
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Date: 2014-08-11T18:58:42-05:00
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"Victor Porton" <porton@narod.ru> wrote in message 
news:ls5tkt$6g2$1@speranza.aioe.org...
> Victor Porton wrote:
>
>> I tried to write:
>>
>> Element(Object)'Access;
>>
>> for "Object" being a value of an instance of
>> Ada.Containers.Indefinite_Holders.
>>
>> This does not work because the return type of Element is not aliased.
>
> By the way, does it makes sense in the next Ada specification to make the
> return type of "Element" function aliased?

Ada doesn't allow return objects to be declared "aliased". We looked at 
allowing that when we added "aliased" parameters, but the semantics would 
have been unusual at best. We couldn't figure out what it mean in various 
usual cases (as you note later, Ada usually allows the return to be a copy, 
and this is important for some kinds of types).

Since it's doesn't make sense (in general) for a return object to be 
aliased, it couldn't make sense to allow that in a generic.

                                                  Randy.