patch::: 1.5.43.jcn2

[lilypond.git] / lily / music-sequence.cc

diff --git a/lily/music-sequence.cc b/lily/music-sequence.cc
index 5ea3514611523d3a320988feae67cd2ae8f14257..69755be0500e03a36e54a7fb7ad2f5fe7b85f66c 100644 (file)
--- a/lily/music-sequence.cc
+++ b/lily/music-sequence.cc
@@ -3,7 +3,7 @@
   
   source file of the GNU LilyPond music typesetter
   
-  (c) 1998--2001 Han-Wen Nienhuys <hanwen@cs.uu.nl>
+  (c) 1998--2002 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   
  */
 #include "music-list.hh"
@@ -100,9 +100,17 @@ Music_sequence::do_relative_octave (Pitch p, bool ret_first)
   Pitch last = p;
   for (SCM s = music_list (); gh_pair_p (s);  s = ly_cdr (s))
     {
-      last = unsmob_music (ly_car (s))->to_relative_octave (last);
-      if (!count ++)
-       retval = last;
+      Music *m = unsmob_music (ly_car (s));
+      if (!m)
+       {
+         programming_error ("Music_sequence should only contain music!");
+       }
+      else
+       {
+         last = m->to_relative_octave (last);
+         if (!count ++)
+           retval = last;
+       }
     }
 
   if (!ret_first)