Check for interpreted-function-p

Emacs 30.x added interpreted-function which is different from
byte-code-function, and hence helpful--signature will try to treat it
like a lambda which will fail with

,----
| (wrong-type-argument listp #[(x) (x) (t) nil "Foo"])
`----

This patch adds tests for such case using interpreted-function-p when
it's available.

1 files changed, 3 insertions, 1 deletions

diff --git a/helpful.el b/helpful.el
index b100816..331ece8 100644
--- a/helpful.el
+++ b/helpful.el
@@ -2570,7 +2570,9 @@ For example, \"(some-func FOO &optional BAR)\"."
             (cond
              ((symbolp sym)
               (help-function-arglist sym))
-             ((byte-code-function-p sym)
+             ((or (byte-code-function-p sym)
+                  (if (fboundp 'interpreted-function-p)
+                      (interpreted-function-p sym)))
               ;; argdesc can be a list of arguments or an integer
               ;; encoding the min/max number of arguments. See
               ;; Byte-Code Function Objects in the elisp manual.