diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index ec2928ee0581ada703a4b00d65f6229862f7a831..08a95f3fd9619ca448559c81f4abfc4831c04b0b 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -3844,13 +3844,13 @@ def default_helper_module!
   module_path = module_name.underscore
   helper module_path
 rescue MissingSourceFile => e
-  raise e unless e.is_missing? "#{module_path}_helper"
+  raise e unless e.is_missing? "helpers/#{module_path}_helper"
 rescue NameError => e
   raise e unless e.missing_name? "#{module_name}Helper"
 end
 ```
 
-NOTE: Defined in `active_support/core_ext/name_error.rb`.
+NOTE: Defined in `actionpack/lib/abstract_controller/helpers.rb`.
 
 Extensions to `LoadError`
 -------------------------