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From: Manos Renieris <er@cs.brown.edu>
To: yminsky@cs.cornell.edu
Cc: Caml Mailing List <caml-list@inria.fr>
Subject: Re: [Caml-list] Another polymorphism puzzle
Date: Thu, 31 Mar 2005 21:52:05 -0500	[thread overview]
Message-ID: <20050401025205.GA4723@cs.brown.edu> (raw)
In-Reply-To: <891bd339050331180214df95db@mail.gmail.com>

Worse:

# let f x = { () with foo = 3};;                    
val f : 'a -> int t = <fun>
# let f x = { 42 with foo = 3};; 
val f : 'a -> int t = <fun>

I think this qualifies as a bug. Especially since the documentation
says the expr on the left hand side of with has to be a record.

Thu, Mar 31, 2005 at 09:02:14PM -0500, Yaron Minsky wrote:
> The last example I posted about had to do with variant types.  Here's
> another interseting little typing surprise having to do with record
> types:
> 
> # type 'a t = { foo: 'a };;
> type 'a t = { foo : 'a; }
> # let f x = { x with foo = 3 };;
> val f : 'a -> int t = <fun>
> 
> I can kind of see how this happened, since after all, the result of (f
> x) does not depend in any way on x.  And yet, it seems like the
> unification rules should force f to have time ('a t -> int t).
> 
> y
> 
> _______________________________________________
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> http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
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  parent reply	other threads:[~2005-04-01  2:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-01  2:02 Yaron Minsky
2005-04-01  2:32 ` [Caml-list] " Karl Zilles
2005-04-01  2:52 ` Manos Renieris [this message]
2005-04-01  4:29   ` Jacques Garrigue
2005-04-01  9:45     ` Alex Baretta

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