* elisp-mode.el: Catch errors from `documentation'

Fixes: debbugs:20418

* lisp/progmodes/elisp-mode.el (elisp--get-fnsym-args-string):
Catch errors from documentation.
(emacs-lisp-mode-abbrev-table): Remove redundant defvar.

1 files changed, 4 insertions, 2 deletions

diff --git a/lisp/progmodes/elisp-mode.el b/lisp/progmodes/elisp-mode.el
index ad35c48a101..f2890686e79 100644
--- a/lisp/progmodes/elisp-mode.el
+++ b/lisp/progmodes/elisp-mode.el
@@ -30,7 +30,6 @@
 
 (require 'lisp-mode)
 
-(defvar emacs-lisp-mode-abbrev-table nil)
 (define-abbrev-table 'emacs-lisp-mode-abbrev-table ()
   "Abbrev table for Emacs Lisp mode.
 It has `lisp-mode-abbrev-table' as its parent."
@@ -1164,7 +1163,10 @@ or elsewhere, return a 1-line docstring."
                   (args
                    (cond
                     ((listp advertised) advertised)
-                    ((setq doc (help-split-fundoc (documentation sym t) sym))
+                    ((setq doc (help-split-fundoc
+                                (condition-case nil (documentation sym t)
+                                  (invalid-function nil))
+                                sym))
                      (car doc))
                     (t (help-function-arglist sym)))))
              ;; Stringify, and store before highlighting, downcasing, etc.