title: Org agenda "wrong number of arguments" error
body: <p>I recently went Win7->Win10 on my work PC and org-agenda is now kicking an error. </p>
  
  <ul>
  <li>GNU Emacs 26.1 (build 1, x86_64-w64-mingw32) of 2018-05-30</li>
  <li>org 9.2.1</li>
  </ul>
  
  <p>I've reduced my org-mode related .emacs down to the following and the issue is persisting.</p>
  
  <pre><code>(custom-set-variables
   '(org-agenda-files (quote ("~/org/inWork.org")))
  )
  </code></pre>
  
  <p>When I run org-agenda 'a', I get an empty agenda, dates only, nothing is captured from inWork.org.  The minibuffer displays <code>Wrong number of arguments: (0 . 0), 2</code></p>
  
  <p>Running the same in debug mode gives a backtrace of </p>
  
  <pre><code>Debugger entered--Lisp error: (wrong-number-of-arguments (0 . 0) 2)
  org-get-tags(nil nil)
  org-agenda-get-deadlines()
  org-agenda-get-day-entries("~/org/inWork.org" (2 7 2019) :deadline :scheduled :timestamp :sexp)
  apply(org-agenda-get-day-entries "~/org/inWork.org" (2 7 2019) (:deadline :scheduled :timestamp :sexp))
  org-agenda-list(nil)
  funcall-interactively(org-agenda-list nil)
  call-interactively(org-agenda-list)
  org-agenda(nil)
  funcall-interactively(org-agenda nil)
  call-interactively(org-agenda nil nil)
  command-execute(org-agenda)
  </code></pre>
  
  <p>org-agenda 't' fails similarly.  I tried stripping down the org files and .emacs as much as possible, but I haven't been able to isolate the issue.</p>
  
  <p>Any help appreciated. </p>