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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Indefinite Containers of Indefinite Private Types
Date: Mon, 3 Aug 2015 19:23:23 -0700
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Date: 2015-08-03T19:23:23-07:00
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This is legal:

package Indefinite1 is
   type T (<>) is private;
private -- Indefinite1
   type T is new String;
end Indefinite1;

with Indefinite1;
with Ada.Containers.Indefinite_Vectors;

package Indefinite2 is
   use type Indefinite1.T;

   package Lists is new Ada.Containers.Indefinite_Vectors
      (Index_Type => Positive, Element_Type => Indefinite1.T);
end Indefinite2;

But this isn't:

with Ada.Containers.Indefinite_Vectors;

package Indefinite1 is
   type T (<>) is private;
private -- Indefinite1
   package Lists is new Ada.Containers.Indefinite_Vectors
      (Index_Type => Positive, Element_Type => T);

   type T is new String;
end Indefinite1;

It seems to me that both instantiations have all the information they need.
Probably I'm missing something, but why is the latter illegal?

-- 
Jeff Carter
"English bed-wetting types."
Monty Python & the Holy Grail
15