maybe should check positions too.
*/
if (right_mus && left_mus
- && ly_c_equal_p (right_mus->get_property ("pitch"),
+ && ly_is_equal (right_mus->get_property ("pitch"),
left_mus->get_property ("pitch")))
{
Grob *p = new Spanner (heads_to_tie_[i].tie_definition_,