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Date: Fri, 18 Jul 2008 22:55:28 +0900 (JST)
Message-Id: <20080718.225528.233096504.garrigue@math.nagoya-u.ac.jp>
To: jeremy.yallop@ed.ac.uk
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Troublesome nodes
From: Jacques Garrigue <garrigue@math.nagoya-u.ac.jp>
In-Reply-To: <20080718.220214.241921104.garrigue@math.nagoya-u.ac.jp>
References: <20080718.113447.241468128.garrigue@math.nagoya-u.ac.jp>
	<488066C9.4050904@ed.ac.uk>
	<20080718.220214.241921104.garrigue@math.nagoya-u.ac.jp>
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X-Spam: no; 0.00; nodes:01 bug:01 nat:01 nat:01 abbreviation:01 expansions:01 cheers:01 caml-list:01 coercion:01 int:01 int:01 cached:02 garrigue:03 garrigue:03 jacques:03 

> It looks like you've found a serious bug in the current
> implementation. Actually you don't even need a coercion:
> 
>   # (((Nat.z : Nat.t :> int) - 1) : Nat.t);;
>   - : Nat.t = -1
> 
> This should certainly not be accepted, as you can see by writing
> 
> # (((Nat.z : Nat.t :> int) - 1) : int :> Nat.t);;  (* fails *)
> 
> I think I know the reason, which is probably related to the way
> abbreviation expansions are cached, but this needs more investigating.

This is now fixed. I just hope this does not break anything...
It should be ok, but please report any new non-termination problem
immediately :-)

Cheers,

Jacques Garrigue