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Message-ID: <3D6658D0.F18A453D@inrialpes.fr>
Date: Fri, 23 Aug 2002 17:46:24 +0200
From: Frederic Tronel <Frederic.Tronel@inrialpes.fr>
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To: caml-list@inria.fr
Subject: [Caml-list] Polymorphic methods
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Hello list,


I've just compiled the new 3.05 version (I will change for 3.06
tomorrow),
and start playing a little bit with polymorphic methods. 
But this small piece of code does not compile:

class node =
object 
val mutable t = None
method set_t: 'a. 'a -> unit = fun nt -> t <- Some nt
end

File "essai.ml", line 4, characters 31-53:
This method has type 'a -> unit which is less general than 'b. 'b ->
unit

while this one is OK (useless).

class node =
object 
val mutable t = None
method set_t: 'a. 'a -> unit = fun nt -> ()
end
class node : object val mutable t : 'a option method set_t : 'b -> unit
end

Where am I going wrong ??

Best regards,

Frederic.
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