diff --git a/docs/function.md b/docs/function.md
index 85565dc..ff610c8 100644
--- a/docs/function.md
+++ b/docs/function.md
@@ -313,7 +313,7 @@ foo() // ReferenceError: x is not defined
 ```javascript
 let foo = 'outer';
 
-function bar(func = x => foo) {
+function bar(func = () => foo) {
   let foo = 'inner';
   console.log(func());
 }