Re: master 7362554: Widen around c-font-lock-fontify-region. This fixes bug #38049.

[Dmitry Gutov <dgutov@yandex.ru>]

On 14.11.2019 0:33, Dmitry Gutov wrote:
> 
> Very interesting, thank you. I wonder if the patch below would fix it as 
> well.

BTW, here's an alternative patch. If CC Mode is fine with only seeing 
the beginning of the buffer until point (for the purpose of maintaining 
its caches), this should work just as well, and it won't have to add a 
(widen) call itself.

diff --git a/lisp/reposition.el b/lisp/reposition.el
index 22f9986efb..5d9c3180ad 100644
--- a/lisp/reposition.el
+++ b/lisp/reposition.el
@@ -174,8 +174,8 @@ reposition-window
  (defun repos-count-screen-lines (start end)
    (save-excursion
      (save-restriction
-      (narrow-to-region start end)
-      (goto-char (point-min))
+      (narrow-to-region (point-min) end)
+      (goto-char start)
        (vertical-motion (- (point-max) (point-min))))))

  ;; Return number of screen lines between START and END; returns a negative