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Troublesome nodes
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Date: 2008-07-17 (00:43)
From: Jacques Garrigue <garrigue@m...>
Subject: Re: [Caml-list] Troublesome nodes
From: Jeremy Yallop <>
> Dario Teixeira wrote:
> >     type ('a, 'b) t = private 'a constraint 'a = [< super_node_t ]
> I don't think this is quite what you want yet, although it's getting
> close!
> The first problem is that phantom types must be implemented in terms
> of abstract (or at least generative) types.

This is actually the other way round: abstract and private types allow
phantom types, but abbreviations and normal datatypes (generative
ones) don't.
So the above code really defines a phantom type.

Jacques Garrigue