From: "Markus Mottl" <markus.mottl@gmail.com>
To: "Stephen Weeks" <sweeks@janestcapital.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] type unsoundness with constraints and polymorphic variants
Date: Mon, 11 Feb 2008 15:46:17 -0500 [thread overview]
Message-ID: <f8560b80802111246o42ddbeccybbe0ba6757c961e8@mail.gmail.com> (raw)
In-Reply-To: <18352.43565.401296.820373@nyc-qws-r03.delacy.com>
On Feb 11, 2008 3:03 PM, Stephen Weeks <sweeks@janestcapital.com> wrote:
> Here is a distillation of the bug. If you compile this, you get a
> warning about line 11 being an unused case. If you then run the
> resulting executable, you get a segfault.
Line 11 can obviously be deleted, the segfault still persists. The
unsoundness seems to appear when the signature constraint is applied
to the module. It should fail, because the identity function is
clearly not a valid instance of this type, since `X can be passed to
it and it would just be returned, thus violating the return type.
It seems that constraints on polymorphic variables are not handled
correctly during the unification of the contents of the module with
its signature.
Regards,
Markus
--
Markus Mottl http://www.ocaml.info markus.mottl@gmail.com
next prev parent reply other threads:[~2008-02-11 20:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-11 20:03 Stephen Weeks
2008-02-11 20:46 ` Markus Mottl [this message]
2008-02-12 4:22 ` [Caml-list] " Jacques Garrigue
2008-02-12 10:35 ` Andrej Bauer
2008-02-12 14:43 ` Luc Maranget
2008-02-13 8:00 ` Jacques Garrigue
2008-02-13 14:15 ` Christopher L Conway
2008-02-13 14:18 ` Michael Hicks
2008-02-13 14:22 ` David Teller
2008-02-13 14:35 ` Till Varoquaux
2008-02-13 14:52 ` Michael Hicks
2008-02-13 14:53 ` Mattias Engdegård
2008-02-13 15:55 ` Christopher L Conway
2008-02-13 16:53 ` Stefano Zacchiroli
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