diff --git a/docs/index-type-operator.md b/docs/index-type-operator.md
index 99c899e..dd8751c 100644
--- a/docs/index-type-operator.md
+++ b/docs/index-type-operator.md
@@ -41,7 +41,7 @@ type Person = {
   alive: boolean
 }
 
-local function doSmt(param: index<Person, "age">) -- param = string
+local function doSmt(param: index<Person, "age">) -- param = number
   -- rest of code
 end