{"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"self.psess.gated_spans.gate(sym::default_field_values,"}]}
            self.psess.gated_spans.gate(sym::default_field_values, sp);
            let sp = ty.span.shrink_to_hi().to(const_expr.value.span);
            Some(const_expr)