error: ‘loop_rate’ was not declared in this scope

edit

In my launch file I have a global variable

<param name = "rateFilterUWB" type="int" value="10" />

and I'm trying to reach this variable's value in my C++ code

    int rateFilterUWB;

if (ros::param::has("/rateFilterUWB")) {
    ros::param::get("/rateFilterUWB", rateFilterUWB);
    ros::Rate loop_rate(rateFilterUWB);
}
else
ros::Rate loop_rate(100);

But I have an error during compilation:

 error: ‘loop_rate’ was not declared in this scope

PS I'm running Linux raspberrypi 4.19.30-v7+