{"ast_node_type":"variable","tokens":[{"end":65,"kind":"keyword","start":0,"text":"let"}]}
            let comment_line = self.sm.lookup_char_pos(cmnt.pos);
            let span_line = self.sm.lookup_char_pos(span.hi());
            let next = next_pos.unwrap_or_else(|| cmnt.pos + BytePos(1));