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From: "G.B." <bauhaus@notmyhomepage.invalid>
Newsgroups: comp.lang.ada
Subject: Does object renaming allow the view to be a copy?
Date: Sun, 22 Jan 2017 09:27:44 +0100
Organization: A noiseless patient Spider
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Date: 2017-01-22T09:27:44+01:00
List-Id: <comp.lang.ada>

A SO answer (41746244) has given rise to the question of whether
or not a compiler implementer may make a renamed object a copy
of the original. (Layman's assumptions from LRM 3.1(7), 8.5.1),

So, is the following program, modifying compoments of and array,
ever allowed to raise Renaming_Is_Copying?

with System;
procedure Renaming is

     Renaming_Is_Copying : exception;

     type R is record
         A, B : Integer;
     end record;

     type List is array (Natural range <>) of R;
     Stuff : List := (10 .. 20 => R'(A => 2, B => 3));
begin
     for K in Stuff'Range loop
         declare
             --
             --  Does Ada allow a compiler to make X be a copy?
             --
             X : R renames Stuff (K);
             use type System.Address;
         begin
             if X'Address = Stuff (K)'Address then
                 X.A := X.B;
             else
                 raise Renaming_Is_Copying;
             end if;
         end;
     end loop;
end Renaming;

-- 
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