{"ast_node_type":"variable","tokens":[{"end":70,"kind":"keyword","start":0,"text":"let"}]}
            let sp = ty.span.shrink_to_hi().to(const_expr.value.span);
            let const_expr = self.parse_expr_anon_const()?;
            self.psess.gated_spans.gate(sym::default_field_values, sp);