diff --git a/src/providers/auth_backend.ts b/src/providers/auth_backend.ts
index 18a3434c8..b32f621bf 100644
--- a/src/providers/auth_backend.ts
+++ b/src/providers/auth_backend.ts
@@ -46,10 +46,10 @@ export interface FirebaseAuthState {
   provider: AuthProviders;
   auth: firebase.User;
   expires?: number;
-  github?: CommonOAuthCredential;
-  google?: GoogleCredential;
-  twitter?: TwitterCredential;
-  facebook?: CommonOAuthCredential;
+  github?: firebase.UserInfo;
+  google?: firebase.UserInfo;
+  twitter?: firebase.UserInfo;
+  facebook?: firebase.UserInfo;
   anonymous?: boolean;
 }
 
@@ -69,7 +69,8 @@ export interface TwitterCredential extends CommonOAuthCredential {
 
 export type OAuthCredential = CommonOAuthCredential | GoogleCredential | TwitterCredential;
 
-export function authDataToAuthState(authData: firebase.User, providerData?: OAuthCredential): FirebaseAuthState {
+export function authDataToAuthState(authData: firebase.User): FirebaseAuthState {
+  let providerData = authData.providerData[0];
   if (!authData) return null;
   let providerId;
   let { uid } = authData;
@@ -80,24 +81,24 @@ export function authDataToAuthState(authData: firebase.User, providerData?: OAut
     authState.anonymous = true;
     return authState;
   } else {
-    providerId = authData.providerData[0].providerId;
+    providerId = providerData.providerId;
   }
 
   switch (providerId) {
     case 'github.com':
-      authState.github = <CommonOAuthCredential>providerData;
+      authState.github = providerData;
       authState.provider = AuthProviders.Github;
       break;
     case 'twitter.com':
-      authState.twitter = <TwitterCredential>providerData;
+      authState.twitter = providerData;
       authState.provider = AuthProviders.Twitter;
       break;
     case 'facebook.com':
-      authState.facebook = <CommonOAuthCredential>providerData;
+      authState.facebook = providerData;
       authState.provider = AuthProviders.Facebook;
       break;
     case 'google.com':
-      authState.google = <GoogleCredential>providerData;
+      authState.google = providerData;
       authState.provider = AuthProviders.Google;
       break;
     case 'password':