From: Alex Baretta <alex@baretta.com>
To: Ocaml <caml-list@inria.fr>
Subject: [Caml-list] Polymorphic records typing question
Date: Mon, 22 Dec 2003 11:50:32 +0100 [thread overview]
Message-ID: <3FE6CC78.8050506@baretta.com> (raw)
Here's a puzzle for the Caml breeders:
# type poly = { f : 'a . 'a -> 'a };;
type poly = { f : 'a. 'a -> 'a; }
# let id x = x;;
val id : 'a -> 'a = <fun>
# let foo = { f = id };;
val foo : poly = {f = <fun>}
# let rec id x = x and foo = { f = id } ;;
This field value has type 'a -> 'a which is less general than 'b. 'b -> 'b
Why is this last recursive definition unacceptable?
Alex
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next reply other threads:[~2003-12-22 13:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-22 10:50 Alex Baretta [this message]
2003-12-22 20:26 ` Guillaume Marceau
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