From: Ben Millwood <bmillwood@janestreet.com>
To: "Grégoire Henry" <gregoire.henry@ocamlpro.com>
Cc: Nicolas Trangez <nicolas@incubaid.com>, Caml-list <caml-list@inria.fr>
Subject: Re: [Caml-list] Strange interaction between recursive modules, GADT exhaustiveness checking and type-checking?
Date: Mon, 30 Jun 2014 12:07:38 +0100 [thread overview]
Message-ID: <CA+MHO50kcPEFnXZsa7cCwXSdk0f92qM3w=x74kgB3vyPEWbbxA@mail.gmail.com> (raw)
In-Reply-To: <20140629144929.GB32483@mlqds.hnr.gr>
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On 29 June 2014 15:49, Grégoire Henry <gregoire.henry@ocamlpro.com> wrote:
> Your first example is a particular case where we could assume that
> 'W.a' and 'W.b' are distinct. They are 'fully abstract types', they
> have no inhabitants. They were introduced in current typing context
> (and not imported from the signature of another module) and we known
> they are distinct.
>
This has bitten me before as well. It seems to me that whether or not a
type is abstract and whether or not it has any values should be essentially
independent characteristics, but it seems impossible to state in a
signature that a type has no constructors. So there's this property of
types that you can't preserve across module boundaries.
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prev parent reply other threads:[~2014-06-30 11:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-28 22:55 Nicolas Trangez
2014-06-29 14:49 ` Grégoire Henry
2014-06-30 11:07 ` Ben Millwood [this message]
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