diff --git a/lisp/ielm.el b/lisp/ielm.el
index 578422001a5..31fb9b90986 100644
--- a/lisp/ielm.el
+++ b/lisp/ielm.el
@@ -491,8 +491,7 @@ addition to `comint-indirect-setup-hook', run this hook with the
 indirect buffer as the current buffer after its setup is done.
 This can be used to further customize fontification and other
 behavior of the indirect buffer."
-  :type 'boolean
-  :safe 'booleanp
+  :type 'hook
   :version "29.1")
 
 (defun ielm-indirect-setup-hook ()