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From: Mart van de Wege <mvdwege@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Can't access record attribute in derived type
Date: Wed, 08 Mar 2017 22:06:12 +0100
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Date: 2017-03-08T22:06:12+01:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:

> I suspect we'll need to see a more complete example to definitively say what 
> the problem is.
>
> But if I had to guess, I'd suggest that you've run afoul of the "sibling 
> inheritance problem". The rule for visibility for child components is that 
> *all* of components of the *all* of the ancestors have to be visible at the 
> point of declaration of the child type. If even one of the ancestors is not 
> visible (as happens when deriving from a type defined in a sibling child 
> package), then the components aren't visible, either.
>
> Note that in such a case, if you have visiblity on some but not all of the 
> ancestors, you can type convert the object to make them visible. In your 
> example above:
>
>      return Creature(K).Parents.First_Element;
>
> will work if you have some intermediate ancestor without visible components. 
> So, if the above works, you have a sibling inheritance problem, and your 
> choices are either to use conversions like the above, or move the types so 
> that all of the ancestors are visible.
>
>                                      Randy.
>
>
>

-- 
"We will need a longer wall when the revolution comes."
    --- AJS, quoting an uncertain source.