An example app to test if PromiseKit imported successfully. https://medium.com/@tingyishih/ios-migrate-from-cocoapods-to-carthage-7be237e4cac0

AppDelegate.swift

import PromiseKit
import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

  var window: UIWindow?
  
  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    let p = Promise.value(0) // A useless promise just for test
    return true
  }

}