[O] pcomplete error inside of headline asterisks when typing asterisk

[stardiviner]

When I create a new headline with =[Alt-Enter]= Under a headline. It looks like 
this:

#+begin_src org
,** headline 1
,** headline 2
#+end_src

Then I move point between two asterisks of headline 2. Then I type * again. It 
report
following error:

#+begin_example
Debugger entered--Lisp error: (args-out-of-range "" 1 nil)
  substring("" 1)
  (pcomplete--here (function (lambda nil (save-excursion (goto-char 
(point-min)) (let (tbl) (let ((case-fold-search nil)) (while (re-search-forward 
org-todo-line-regexp nil t) (setq tbl (cons (org-make-org-heading-search-string 
(match-string-no-properties 3)) tbl)))) (pcomplete-uniquify-list tbl))))) 
(substring pcomplete-stub 1) nil nil)
  (while (pcomplete--here (function (lambda nil (save-excursion (goto-char 
(point-min)) (let (tbl) (let ((case-fold-search nil)) (while (re-search-forward 
org-todo-line-regexp nil t) (setq tbl (cons (org-make-org-heading-search-string 
(match-string-no-properties 3)) tbl)))) (pcomplete-uniquify-list tbl))))) 
(substring pcomplete-stub 1) nil nil))
  pcomplete/org-mode/searchhead()
  pcomplete-completions()
  pcomplete-completions-at-point()
  completion--capf-wrapper(pcomplete-completions-at-point optimist)
  run-hook-wrapped(completion--capf-wrapper pcomplete-completions-at-point 
optimist)
  company--capf-data-real()
  company--capf-data()
  company-capf(prefix)
  apply(company-capf prefix)
  company-call-backend-raw(prefix)
  apply(company-call-backend-raw prefix)
  company--force-sync(company-call-backend-raw (prefix) company-capf)
  company-call-backend(prefix)
  company--begin-new()
  company--perform()
  company-auto-begin()
  company-idle-begin(#<buffer Slack.org> #<window 34 on Slack.org> 182 2857)
  apply(company-idle-begin (#<buffer Slack.org> #<window 34 on Slack.org> 182 
2857))
  timer-event-handler([t 23486 42991 304203 nil company-idle-begin (#<buffer 
Slack.org> #<window 34 on Slack.org> 182 2857) nil 151000])
#+end_example

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