&& !type_check_assignment (sym, v, ly_symbol2scm ("backend-type?")))
abort ();
check_interfaces_for_property (this, sym);
&& !type_check_assignment (sym, v, ly_symbol2scm ("backend-type?")))
abort ();
check_interfaces_for_property (this, sym);
&& !type_check_assignment (sym, val,
ly_symbol2scm ("backend-type?")))
abort ();
&& !type_check_assignment (sym, val,
ly_symbol2scm ("backend-type?")))
abort ();