{"ast_node_type":"variable","tokens":[{"end":65,"kind":"keyword","start":0,"text":"let"}]}
            let span = self.mk_sp(last_line_start_pos, self.pos);
        if !rest.trim_matches(is_whitespace).is_empty() {
            self.dcx().emit_err(errors::FrontmatterExtraCharactersAfterClose { span });