indirect+loe.swift

indirect+loe.swift

func update<T>(value: inout T, update: (inout T) -> Void) {
    update(&value)
}

struct Hoge {
    var list: List<Int>
}

enum List<T> {
    case `nil`
    indirect case cons(T, List<T>)
}

var hoge = Hoge(list: List.cons(1, .cons(2, .nil)))

update(value: &hoge) { h in
    let list = h.list
    // Simultaneous accesses to 0x10b087578, but modification requires exclusive access.
    h.list = List.cons(10, list)
}