Fix 1220.

[lilypond.git] / lily / rest-collision-engraver.cc

diff --git a/lily/rest-collision-engraver.cc b/lily/rest-collision-engraver.cc
index 7156409d51dd0adb7140b9171d3babef6255472d..cb9a35d0d1eb601ad5f1dcd506cdbc37bc9ea087 100644 (file)
--- a/lily/rest-collision-engraver.cc
+++ b/lily/rest-collision-engraver.cc
@@ -1,15 +1,27 @@
 /*
-  rest-collision-engraver.cc -- implement Rest_collision_engraver
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the GNU LilyPond music typesetter
+  Copyright (C) 1997--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
-  (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  LilyPond is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  LilyPond is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include <set>
 
 #include "duration.hh"
 #include "engraver.hh"
+#include "international.hh"
 #include "item.hh"
 #include "moment.hh"
 #include "note-column.hh"
@@ -53,6 +65,11 @@ Rest_collision_engraver::process_acknowledged ()
       if (Rhythmic_head::has_interface (g) && (*m) > now)
        {
          Grob *column = g->get_parent (X_AXIS);
+         if (!column)
+           {
+             g->warning (_ ("rhythmic head is not part of a rhythmic column"));
+             continue;
+           }
 
          // Only include rests that start now. Include notes that started any time.
          Paper_column *paper_column = dynamic_cast<Item*> (column)->get_column ();