- if ((unsmob_pitch (val)
- || (prop == ly_symbol2scm ("element") && unsmob_music (val))
- || (prop == ly_symbol2scm ("elements") && scm_is_pair (val))
- || (prop == ly_symbol2scm ("pitch-alist") && scm_is_pair (val)))
- && scm_is_false (scm_assq (prop, mutable_property_alist_)))
- mutable_property_alist_ =
- scm_acons (prop, ly_music_deep_copy (val), mutable_property_alist_);
+ if ((unsmob<Pitch> (val)
+ || (scm_is_eq (prop, ly_symbol2scm ("element")) && unsmob<Music> (val))
+ || (scm_is_eq (prop, ly_symbol2scm ("elements")) && scm_is_pair (val))
+ || (scm_is_eq (prop, ly_symbol2scm ("pitch-alist")) && scm_is_pair (val)))
+ && scm_is_false (scm_assq (prop, mutable_property_alist_)))
+ mutable_property_alist_
+ = scm_acons (prop, music_deep_copy (val), mutable_property_alist_);