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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
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Subject: Re: Performance of records with variant parts
Date: Thu, 1 Apr 2021 16:38:46 +0300
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On 2021-04-01 3:03, John Perry wrote:

> A function returns an Intersection_Type, which has several fields,
> one of which was a Thing_Type. So if Thing_Type is variant,
> Intersection_Type also has to be variant.

No.

I assume by "X is variant" you mean that X has a variant_part (RM 3.8.1(2)).

If the discriminant of Thing_Type has a default value, Intersection_Type 
can have a Thing_Type component without supplying it with a discriminant 
value, and Intersection_Type need not have discriminants nor a variant part.