[gtk/matthiasc/for-master] more assertions

[Matthias Clasen <matthiasc src gnome org>]

commit 6d5019ad3ecfb2416a44cb9fc78ee04a93a88c2d
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Apr 12 12:56:04 2020 -0400

    more assertions

 gtk/gtkstylecontext.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 15e0085537..13b78ec585 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -1351,6 +1351,7 @@ gtk_snapshot_render_insertion_cursor (GtkSnapshot     *snapshot,
   g_return_if_fail (GTK_IS_STYLE_CONTEXT (context));
   g_return_if_fail (PANGO_IS_LAYOUT (layout));
   g_return_if_fail (index >= 0);
+  g_return_if_fail (index <= strlen (pango_layout_get_text (layout)));
 
   g_object_get (gtk_settings_get_for_display (priv->display),
                 "gtk-split-cursor", &split_cursor,