a weakness in help.el?

[Tak Ota]

Under Emacs 20.7 `help-follow' fails.

How to reproduce:

1. Make a test file say "test.el" which content is:

;; test.el begins here
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'advice)
(require 'tabify)

(defadvice untabify (around advised-untabify last activate compile)
  ad-do-it
  (message "executed original `untabify'"))

(defmacro test-advice (func)
  (`
   (defadvice (, func) (around advised-tabify last activate compile)
     ad-do-it
     (message "executed original `tabify'"))))

(test-advice tabify)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; test.el ends here


2. Start a fresh Emacs by "emacs -q -no-site-file".

3. M-x describe-function "tabify"

4. help-follow (hit RET) on the file name on the first line.

5. Get an error "Cannot find definition of `tabify' in library ..."

While

6. M-x describe-function "untabify"

7. help-follow (hit RET) on the file name on the first line.

8. test.el opens in a buffer and point goes to where `untabify' is
   advised.


Is this an expected limitation in help.el?  How difficult is it to
find an advice made by a macro?

-Tak