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Newsgroups: comp.lang.ada
Date: Mon, 25 Nov 2019 11:31:11 -0800 (PST)
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Subject: Re: yes another gnat bug (inherited tagged type as record field is
 too much for gnat??)
From: gerrshapovalov@gmail.com
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Xref: reader01.eternal-september.org comp.lang.ada:57606
Date: 2019-11-25T11:31:11-08:00
List-Id: <comp.lang.ada>

A short update:
After playing around some more I narrowed it down to gnat having some problem with discriminant handling. Basically

type FRec is record
  f : List(5);
end record
R : FRec;
--
R.f(1) := 1; -- still works (as in compiles *and* executes Ok)

but

type FRec (N : Positive) is record
  f : List(N);
end record
R : FRec(5);
--
R.f(1) := 1; -- triggers the bug


I have updated the "demo" (tests) package. 
( https://github.com/gerr135/ada_composition ,  the ada_lists_tests dir)
Now simply calling make should just build the (non-failing) tests. 

To trigger the bug run:
make bug01