OurCache.swift

//
//  OurCache.swift
//  ConflictingSymbolsViaProtocolExtensions
//
//  Created by Alan Zeino on 7/19/17.
//  Copyright © 2017 Alan Zeino. All rights reserved.
//

import Foundation

protocol Caching {
    func objectForKey(_ key: AnyObject) -> AnyObject?

    func removeObjectForKey(_ key: AnyObject)
}

class OurCache: NSCache<AnyObject, AnyObject>, Caching { }

let theCache = OurCache()
let obj = theCache.object(forKey: "foo" as AnyObject)

Foundation.NSCache:8:15: error: unavailable instance method 'objectForKey' was used to satisfy a requirement of protocol 'Caching'
    open func objectForKey(_ key: KeyType) -> ObjectType?
              ^
/Users/alan/Desktop/ConflictingSymbolsViaProtocolExtensions/ConflictingSymbolsViaProtocolExtensions/OurCache.swift:12:10: note: requirement 'objectForKey' declared here
    func objectForKey(_ key: AnyObject) -> AnyObject?
         ^