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ytomino/magicmoduletype.ml

Created April 25, 2021 01:44
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GADTの型パラメータをObj.magicで一致させることで無関係な後続の式の型チェックを回避できる
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magicmoduletype.ml
module type T1 = sig
type t (* any abstract type *)
val one: t
end;;
module M1: T1 = Int;;
type 'a repr = C1: M1.t repr (* GADT is needed *)
let one: string =
let C1 = (Obj.magic C1: string repr) in (* force M1.t = string *)
M1.one;; (* !!! *)
print_string one;; (* segmentation fault *)
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