Adds is_null check to Eloquent Builder callScope

Author: alihamze

src/Illuminate/Database/Eloquent/Builder.php

@@ -924,7 +924,7 @@ protected function callScope(callable $scope, $parameters = [])
         // We will keep track of how many wheres are on the query before running the
         // scope so that we can properly group the added scope constraints in the
         // query as their own isolated nested where statement and avoid issues.
-        $originalWhereCount = count($query->wheres);
+        $originalWhereCount = is_null($query->wheres) ? 0 : count($query->wheres);
 
         $result = $scope(...array_values($parameters)) ?: $this;