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From: Maciej Sobczak <no.spam@no.spam.com>
Newsgroups: comp.lang.ada
Subject: Dynamically tagged expression required
Date: Thu, 08 Dec 2005 14:50:37 +0100
Organization: CERN - European Laboratory for Particle Physics
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Date: 2005-12-08T14:50:37+01:00
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Hi,

procedure Hello is

    type Shape is tagged null record;
    type Triangle is new Shape with
      record
         SideLen : Positive;
      end record;

    A : Shape;
    B : Shape'Class := A;             -- (1)
    C : Triangle := (SideLen => 7);

begin

    A := C;                           -- (2)
    B := C;                           -- (3)

end Hello;


(2) does not compile, and this is what was expected.
(3) does not compile, neither, beucase "dynamically tagged expression 
required".

Interestingly, (1) is fine.

Why is (1) allowed?
Why is (3) not allowed?

Regards,

-- 
Maciej Sobczak : http://www.msobczak.com/
Programming    : http://www.msobczak.com/prog/