title: Firebase Phone Authentication credentials linking with Google login in firebase
body: <p>I have implemented two step authentication in my app using firebase authentication in which I have used gmail, facebook or simple email login for authenticating. As digits phone verification has migrated to firebase i have implemented firebase phone authentication by linking the existing logged in account (facebook, gmail, or email) with phone authentication credentials. It works fine when used with facebook and email account. When user is logged in through google and tries to verify mobile through phone authentication this logs are printed :</p>
  <blockquote>
  <p>signInWithCredential:failure</p>
  <p>com.google.firebase.auth.FirebaseAuthUserCollisionException: An account already exists with the same email address but different sign-in credentials. Sign in using a provider associated with this email address.</p>
  </blockquote>
  <p>Read this <a href="https://groups.google.com/forum/#!searchin/firebase-talk/liu/firebase-talk/ms_NVQem_Cw/8g7BFk1IAAAJ" rel="noreferrer">article</a>. Is it the same issue as mentioned in the <a href="https://groups.google.com/forum/#!searchin/firebase-talk/liu/firebase-talk/ms_NVQem_Cw/8g7BFk1IAAAJ" rel="noreferrer">article</a>?? Is there any solution for the same..</p>