Objヤバイ # type foo = { count : int };; type foo = { count : int; } # let x = { count = 4 };; val x : foo = {count = 4} # Obj.set_field (Obj.repr x) 0 (Obj.repr 8);; - : unit = () # x;; - : foo = {count = 8}うぎゃ。Obj.set_field (Obj.repr…