diff --git a/src/Illuminate/Database/Schema/Blueprint.php b/src/Illuminate/Database/Schema/Blueprint.php
index e6c5c54343b2..a20fd190da9e 100755
--- a/src/Illuminate/Database/Schema/Blueprint.php
+++ b/src/Illuminate/Database/Schema/Blueprint.php
@@ -901,6 +901,22 @@ public function morphs($name, $indexName = null)
         $this->index(["{$name}_id", "{$name}_type"], $indexName);
     }
 
+    /**
+     * Add nullable columns for a polymorphic table.
+     *
+     * @param  string  $name
+     * @param  string|null  $indexName
+     * @return void
+     */
+    public function nullableMorphs($name, $indexName = null)
+    {
+        $this->unsignedInteger("{$name}_id")->nullable();
+
+        $this->string("{$name}_type")->nullable();
+
+        $this->index(["{$name}_id", "{$name}_type"], $indexName);
+    }
+
     /**
      * Adds the `remember_token` column to the table.
      *
diff --git a/src/Illuminate/Events/Dispatcher.php b/src/Illuminate/Events/Dispatcher.php
index 32e9990558ed..ba0bed137f49 100755
--- a/src/Illuminate/Events/Dispatcher.php
+++ b/src/Illuminate/Events/Dispatcher.php
@@ -329,7 +329,13 @@ protected function addInterfaceListeners($eventName, array $listeners = [])
     {
         foreach (class_implements($eventName) as $interface) {
             if (isset($this->listeners[$interface])) {
-                $listeners = array_merge_recursive($listeners, $this->listeners[$interface]);
+                foreach ($this->listeners[$interface] as $priority => $names) {
+                    if (isset($listeners[$priority])) {
+                        $listeners[$priority] = array_merge($listeners[$priority], $names);
+                    } else {
+                        $listeners[$priority] = $names;
+                    }
+                }
             }
         }