Remove unused param on both method and call, using class variable instead

app/controllers/users/omniauth_callbacks_controller.rb

@@ -30,7 +30,7 @@ class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController
       identity = Identity.first_or_create_from_oauth(auth)
       @user = current_user || identity.user || User.first_or_initialize_for_oauth(auth)
 
-      if save_user(@user)
+      if save_user
         identity.update(user: @user)
         sign_in_and_redirect @user, event: :authentication
         set_flash_message(:notice, :success, kind: "#{provider}".capitalize) if is_navigational_format?
@@ -40,7 +40,7 @@ class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController
       end
     end
 
-    def save_user(user)
+    def save_user
       @user.save || @user.save_requiring_finish_signup
     end