Doing a M-x eval-buffer on a file containing this:

(funcall
 (let ((a 0))
   (lambda ()
     a)))

;; Local Variables:
;; lexical-binding: t
;; End:

Will result in an error:

funcall: Symbol's value as variable is void: a

But a file containing this:

;; -*- lexical-binding: t -*-

(funcall
 (let ((a 0))
   (lambda ()
     a)))

Will work as expected. No problem.

I was expecting these these to be equivalent. I checked the manual, "Specifying File Variables" and that seems to say that using either the first line or variable list should have the same effect.

(I'm not sure about the exact version of Emacs. It's probably old, I'm on Ubuntu 14.04 at the moment. Dpkg reports 24.3+1-2ubuntu1.)

-- Tim