{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"$cx.emit_err(session_diagnostics::StabilityOutsideStd"}]}
            $cx.emit_err(session_diagnostics::StabilityOutsideStd { span: $cx.attr_span });
        if !$cx.features().staged_api() {
            return;