Trying to use vala-mode in emacs:

c-get-lang-constant: Invalid function: "\\s *#\\s *"

I looked for my vala-mode.el and found I was using a local copy I had set up last year,



~/.emacs.d/lisp/vala-mode.el



It was from 2015-05-27, however, that seemed to be the latest copy.  I replaced it anyway, (despite diff showing no differences) and "magically" it resumed working.  Hmm.  Maybe it was also just me restarting my emacs daemon. :D