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[Caml-list] polymorphic variant question
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Date: -- (:)
From: nadji@n...
Subject: [Caml-list] polymorphic variant question
Hi all,

I am puzzled by the code below which doesn't work.

# let f = function `B -> ();;
val f : [ `B] -> unit = <fun>
# let g x = match (x:[`A|`B]) with `A -> () | y -> f y;;
Characters 51-52:
  let g x = match (x:[`A|`B]) with `A -> () | y -> f y;;
                                                     ^
This expression has type [ `A | `B] but is here used with type [ `B]
(denoting the "y" from the "f y")

How can I say to OCaml that "y" can't be of type `A ?

TIA,
Nadji

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