From: Christopher Zimmermann <christopher@gmerlin.de>
To: caml-list@inria.fr
Subject: [Caml-list] matching GADT option types
Date: Thu, 17 Jan 2019 10:46:11 +0100 [thread overview]
Message-ID: <20190117104611.3288dd5a@mortimer.gmerlin.de> (raw)
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Hi,
why does the f type correctly while g fails to type?
Christopher
type 'a t =
| A : unit t
let f =
fun (type a) ~(p :a t option) () -> match p with
| Some A -> ()
| None -> ()
let g =
fun (type a) ~(p :a t option) () -> match p with
| Some A (* TYPING ERROR HERE *)
| None -> ()
Error: This pattern matches values of type unit t
but a pattern was expected which matches values of type a t
Type unit is not compatible with type a
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next reply other threads:[~2019-01-17 9:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-17 9:46 Christopher Zimmermann [this message]
2019-01-17 9:58 ` Jeremy Yallop
2019-01-17 10:02 ` Christopher Zimmermann
2019-01-17 10:18 ` Gabriel Scherer
2019-01-17 10:12 ` Gabriel Scherer
2019-01-17 10:08 ` Christopher Zimmermann
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