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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: I am leaving Ada :-( because of GNAT bugs
Date: Sat, 09 Dec 2017 09:35:22 +0000
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Date: 2017-12-09T09:35:22+00:00
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bj.mooremr@gmail.com writes:

> On Thursday, December 7, 2017 at 12:45:11 AM UTC-7, Victor Porton wrote:
>> Yet one mysterious bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83310

> I am not sure which version of GNAT you are using, GPL for FSF. Both
> are good quality compilers, but if you are running into compiler bugs
> in one, it might be worth trying your source in the other. For your
> source code, I was trying it out with GNAT GPL 2017.

OP said 7.2.0, => FSF.

> 2. For a number of the tagged types, the Parse function had the
> controlling parameter as the second parameter. I think Ada might allow
> that, but I generally put the controlling parameter (the one that has
> the same type as the tagged type), at the beginning as the first
> parameter.

It has to be the first parameter for object prefix notation to work (ARM
4.1.3(9.1) - that took some finding!)

> 9. In rdf-redland-query_results.ads, you declare a type derived from a
> tagged type, but then try to apply a Pre'Class aspect. This apparently
> is not legal, though the GPL 2016 compiler doesn't complain. I ran
> into this, with my own code, that GPL 2017 told me with a compiler
> error that the code was not legal.
>
> Pre'Class can only be applied to a root type apparently.

See ARM 6.1.1(17.1/4), "Pre'Class shall not be specified for an
overriding primitive subprogram of a tagged type T unless the Pre'Class
aspect is specified for the corresponding primitive subprogram of some
ancestor of T."