Swift 2.2 bug with optimization on

Swift2_2_ARCBug.swift

// This shows a bug in Swift 2.2 (and 2.3) where `self` gets released in a recursive call

extension Dictionary {
    mutating func append(_ other: [String: AnyObject]) {
        // 2. After the call 1. below, `other` would have been dealloced in the recursive call :(
        for (key, value) in other {
            if let otherSubDict = value as? [String: AnyObject],
                var selfSubDict = self[key] as? AnyObject as? [String: AnyObject]
            {
                // 1. Make a recursive call
                selfSubDict.append(otherSubDict)
                self.updateValue(selfSubDict, forKey: key)
            } else {
                self.updateValue(value, forKey: key)
            }
        }
    }

    subscript (key: AnyObject) -> Value? {
        if let key = key as? Key {
            return self[key]
        }
        return nil
    }

    mutating func updateValue(_ value: AnyObject, forKey key: AnyObject) {
        if let value = value as? Value, let key = key as? Key {
            self.updateValue(value, forKey: key)
        }
    }

}

func testAppend() {
    
    let key = "names"
    var info = [
        key:
            [ "first": "Raheel" ]
    ]
    info.append([
        key: ["second": "Ahmad"]
        ]
    )
    print(info)
}

This shows a bug in Swift 2.2 (and 2.3) in Release build, with optimization on. The passed argument other gets released in a recursive call. Supposedly, has to do with ARC (Dictionary uses ARC internally). Does not affect Swift 3.0