diff --git a/core/lib/Drupal/Core/Theme/Registry.php b/core/lib/Drupal/Core/Theme/Registry.php
index 094780a10e..46be6b9b49 100644
--- a/core/lib/Drupal/Core/Theme/Registry.php
+++ b/core/lib/Drupal/Core/Theme/Registry.php
@@ -485,10 +483,7 @@ protected function processExtension(array &$cache, $name, $type, $theme, $path)
         // system.module to declare theme functions on behalf of core .include
         // files.
         if (isset($info['file'])) {
-          $include_file = isset($info['path']) ? $info['path'] : $path;
-          $include_file .= '/' . $info['file'];
-          include_once $this->root . '/' . $include_file;
-          $result[$hook]['includes'][] = $include_file;
+          throw new \Exception();
         }
 
         // A template file is the default implementation for a theme hook, but