bug#20146: font-lock-extend-jit-lock-region-after-change: results are discarded instead of being returned.

[Alan Mackenzie]

Hi, Emacs

In font-lock-extend-jit-lock-region-after-change in font-lock.el, the
new fontification region is calculated by funcalling
font-lock-extend-after-change-region-function.  The result of this
funcall is assigned to internal variables beg and end.

To return these values to the caller, they should be written to the
dynamically bound variables jit-lock-start and jit-lock-end.  This is
only done in the case

    (memq 'font-lock-extend-region-wholelines
           font-lock-extend-region-functions)

.  It should be done in all cases.

-- 
Alan Mackenzie (Nuremberg, Germany).