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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: Extension of non-limited type needs limited component
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Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> writes:

> Which also raises an interesting question, whether T'Class should
> always inherit "non-limitness" of T. Or more generally shouldn't one
> have an ability to disallow primitive operations (like ":=" in case of
> non-limited->limited mutation)?
> 
> Let we allow disallowing, then either
> 
> 1. ":=" should dispatch in X:=Y to a disallowed operation, thus raise
> an exception and so refuse to copy the limited components.

Compile time errors are good.  Exceptions (run-time errors) are evil.
This is not SmallTalk, where you can dispatch to a method that does not
exist.

- Bob