diff --git a/index.js b/index.js
index 67deed4..9c26390 100644
--- a/index.js
+++ b/index.js
@@ -60,6 +60,7 @@ module.exports = {
 
     'no-shadow': ['error', {
       allow: ['_'],
+      builtinGlobals: true,
     }],
 
     // don't enforce extension rules