vim-patch:7.4.320

Problem:    Possible crash when an BufLeave autocommand deletes the buffer.
Solution:   Check for the window pointer being valid.  Postpone freeing the
            window until autocommands are done. (Yasuhiro Matsumoto)

https://code.google.com/p/vim/source/detail?r=v7-4-320

src/nvim/window.c

@@ -3679,7 +3679,12 @@ win_free (
 
   if (wp != aucmd_win)
     win_remove(wp, tp);
-  free(wp);
+  if (autocmd_busy) {
+    wp->w_next = au_pending_free_win;
+    au_pending_free_win = wp;
+  } else {
+    free(wp);
+  }
 
   unblock_autocmds();
 }