title: GoogleAuth using Firebase in IOS
body: <p>I am following the instructions of the official Firebase channel (<a href="https://firebase.google.com/docs/auth/ios/google-signin?hl=en-419" rel="noreferrer">https://firebase.google.com/docs/auth/ios/google-signin?hl=en-419</a>) to subscribe into my app using Google authentication. The problem appears in the function </p>
  
  <pre><code>func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error?)  
  </code></pre>
  
  <p>Where it does not resolve the identifiers GoogleAuthProvider and Auth from the commands. i.e. "Use of unresolved identifier 'GoogleAuthProvider'"</p>
  
  <pre><code>let credential = GoogleAuthProvider.credential(idToken: authentication.idToken, accessToken: authentication.accessToken)
          // ...
  Auth.auth().signIn(with: credential) { (user, error) in
              if let error = error {
                  // ...
                  return
              } 
  </code></pre>
  
  <p>I imported in both the viewer and the AppDelegate:</p>
  
  <pre><code>import Firebase
  import GoogleSignIn
  </code></pre>
  
  <p>And my Podfile looks like that:</p>
  
  <pre><code># Uncomment the next line to define a global platform for your project
  # platform :ios, '9.0'
  
  target 'racc' do
    # Comment the next line if you're not using Swift and don't want to use dynamic frameworks
    use_frameworks!
  
    # Pods for racc
    pod 'Firebase/Core'
    pod 'GoogleSignIn'
    pod 'Firebase/Auth'
  
    target 'raccTests' do
      inherit! :search_paths
      # Pods for testing
    end
  
  end
  </code></pre>
  
  <p>I am working in Swift 4</p>