289         let mut start = self.add_empty();  in compile()
395                 let id = self.add_empty();  in c()
461         let end = self.add_empty();  in c_alternation()
540         let empty = self.add_empty();  in c_bounded()
603         let empty = self.add_empty();  in c_zero_or_one()
616         let end = self.add_empty();  in c_byte_class()
633             let end = self.add_empty();  in c_unicode_class()
732         let alt_end = self.add_empty();  in c_unicode_class_reverse_with_suffix()
765         let id = self.add_empty();  in c_empty()
806     fn add_empty(&self) -> StateID {  in add_empty()  method
892         let target = nfac.add_empty();  in new()
895         utf8c.add_empty();  in new()
961     fn add_empty(&mut self) {  in add_empty()  method