doc fixes, rune pats

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

diff --git a/lily/music-sequence.cc b/lily/music-sequence.cc
index b7e0e5695498090f7a27da241857dea3fa6cfa14..69755be0500e03a36e54a7fb7ad2f5fe7b85f66c 100644 (file)
--- a/lily/music-sequence.cc
+++ b/lily/music-sequence.cc
@@ -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)