Make checkdoc work better with cl-lib functions

* lisp/emacs-lisp/checkdoc.el (checkdoc-defun-info): Make checkdoc
work for cl-lib methods with more complex parameter lists
(bug#37063).

Copyright-paperwork-exempt: yes

1 files changed, 2 insertions, 3 deletions

diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
index 51fb75da691..6c40bdf632e 100644
--- a/lisp/emacs-lisp/checkdoc.el
+++ b/lisp/emacs-lisp/checkdoc.el
@@ -1952,11 +1952,10 @@ from the comment."
         ;; new obarray.
         (if (not (listp lst)) (setq lst nil))
         (unless is-advice
-          ;; lst here can be something like ((foo bar) baz) from
+          ;; (car lst) can be something like ((foo bar) baz) from
           ;; cl-lib methods; flatten it:
-          (setq lst (flatten-tree lst))
           (while lst
-            (setq ret (cons (symbol-name (car lst)) ret)
+            (setq ret (cons (symbol-name (car (flatten-tree (car lst)))) ret)
                   lst (cdr lst)))))
       (nreverse ret))))