From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <jeremy.yallop@ed.ac.uk>
X-Original-To: caml-list@yquem.inria.fr
Delivered-To: caml-list@yquem.inria.fr
Received: from mail3-relais-sop.national.inria.fr (mail3-relais-sop.national.inria.fr [192.134.164.104])
	by yquem.inria.fr (Postfix) with ESMTP id C8820BBAF
	for <caml-list@yquem.inria.fr>; Sat, 12 Jul 2008 20:27:47 +0200 (CEST)
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AhIDABaUeEhTkhUHgWdsb2JhbACSLAEBECADljE
X-IronPort-AV: E=Sophos;i="4.30,350,1212357600"; 
   d="scan'208";a="15057777"
Received: from smtp.bulldogdsl.com (HELO cht-smtp-001.bulldogdsl.com) ([83.146.21.7])
  by mail3-smtp-sop.national.inria.fr with ESMTP; 12 Jul 2008 20:27:47 +0200
Received: by cht-smtp-001.bulldogdsl.com (Postfix, from userid 1011)
	id 7BCF24E69A8; Sat, 12 Jul 2008 19:27:46 +0100 (BST)
X-Spam-Abuse: Please report all spam/abuse matters to abuse@bulldogdsl.com
X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on 
	cht-smtp-001.bddsl.net
X-Spam-Level: 
Received: from [192.168.123.191] (host-84-9-232-7.dslgb.com [84.9.232.7])
	by cht-smtp-001.bulldogdsl.com (Postfix) with ESMTP id EAC474E68CB;
	Sat, 12 Jul 2008 19:27:43 +0100 (BST)
Message-ID: <4878F79F.30604@ed.ac.uk>
Date: Sat, 12 Jul 2008 19:27:43 +0100
From: Jeremy Yallop <jeremy.yallop@ed.ac.uk>
User-Agent: Mozilla-Thunderbird 2.0.0.14 (X11/20080509)
MIME-Version: 1.0
To: Dario Teixeira <darioteixeira@yahoo.com>
Cc: Wolfgang Lux <wlux@uni-muenster.de>, caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Troublesome nodes
References: <761520.40658.qm@web54603.mail.re2.yahoo.com>
In-Reply-To: <761520.40658.qm@web54603.mail.re2.yahoo.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Spam: no; 0.00; nodes:01 node:01 node:01 rhs:01 wrote:01 matched:01 caml-list:01 match:02 match:02 refine:03 pattern:04 convert:11 convert:11 type:14 super:24 

Dario Teixeira wrote:
>     and convert_super_node node = match node with
>         | #nonlink_node_t   -> (convert_nonlink_node node :> super_node_t)
>         | #link_node_t      -> (convert_link_node node :> super_node_t)

You need to rebind the matched value within the pattern in order to 
refine the type on the rhs:

and convert_super_node node = match node with
| #nonlink_node_t as node -> (convert_nonlink_node node :> super_node_t)
| #link_node_t    as node -> (convert_link_node node :> super_node_t)

Jeremy.