Weirdness with Agenda and "C-u r"

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Something seems to have gone off with the `org-tags-view' Agenda view:
if I hit "C-u r" to search with another string, I get this traceback:

Debugger entered--Lisp error: (invalid-function 4)
  (4)
  (org-tags-view (4) (if current-prefix-arg nil "publishing"))
  (let nil (org-tags-view (4) (if current-prefix-arg nil "publishing")))
  eval((let nil (org-tags-view (4) (if current-prefix-arg nil "publishing"))))
  org-let(nil (org-tags-view (4) (if current-prefix-arg nil "publishing")))
  org-agenda-redo((4))
  funcall-interactively(org-agenda-redo (4))
  call-interactively(org-agenda-redo nil nil)
  command-execute(org-agenda-redo)

I tried e-debugging `org-agenda-redo', but something magic happens when
it gets to the org-let, and no light was shed.

I seem to remember there have been some changes to the tag matching code
recently -- maybe that's it? Happy to bisect if necessary.

Eric