Testing hashable weak reference

WeakTest.swift

import Foundation

class WeakWrapper: Hashable {
    private(set) weak var value: AnyObject?

    init(_ value: AnyObject) {
        self.value = value
    }

    static func == (lhs: WeakWrapper, rhs: WeakWrapper) -> Bool {
        lhs.value === rhs.value
    }

    func hash(into hasher: inout Hasher) {
        value?.pointerValue?.hash(into: &hasher)
    }
}

class Test { }

func createSet() -> Set<WeakWrapper> {
    var result = Set<WeakWrapper>()
    let v1 = Test()
    result.insert(WeakWrapper(v1))

    let v2 = Test()
    result.insert(WeakWrapper(v2))

    let v3 = Test()
    result.insert(WeakWrapper(v3))

    return result
}

var set = createSet()
let hasNilValues = set.contains { $0.value == nil }
if hasNilValues {
    print("Found nil values")
    let v4 = Test()
    set.insert(WeakWrapper(v4))
    print("Inserted")
} else {
    print("No nil values")
}