From b681be175b6991cdc2b8ddd49b0e97e3fe2b201e Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Thu, 31 Mar 2016 23:02:16 +0200
Subject: [PATCH] patch 7.4.1691 Problem:    When switching to a new buffer and
 an autocommand applies syntax             highlighting an ml_get error may
 occur. Solution:   Check "syn_buf" against the buffer in the window.
 (Alexander von             Buddenbrock, closes #676)

---
 src/syntax.c  | 4 +++-
 src/version.c | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/syntax.c b/src/syntax.c
index 29b68886b..a43f4a63a 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -509,7 +509,9 @@ syntax_start(win_T *wp, linenr_T lnum)
      * Also do this when a change was made, the current state may be invalid
      * then.
      */
-    if (syn_block != wp->w_s || changedtick != syn_buf->b_changedtick)
+    if (syn_block != wp->w_s
+	    || syn_buf != wp->w_buffer
+	    || changedtick != syn_buf->b_changedtick)
     {
 	invalidate_current_state();
 	syn_buf = wp->w_buffer;
diff --git a/src/version.c b/src/version.c
index 3fa82ca88..d08e7307b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1691,
 /**/
     1690,
 /**/