Need help finding the definition of a method-CodePudding

I've come across this file in Elementor: wp-content/plugins/elementor/includes/base/controls-stack.php, from line 2202 to 2211 is

protected function render() {}

/**
 * Render element in static mode.
 *
 * If not inherent will call the base render.
 */
protected function render_static() {
    $this->render();
}

As you can see in line 2202 this render method is empty. What I don't understand is if method render does nothing, then what does $this->render() do? Actually on the same file, the method render is called several times. I have also checked the parent object Base_Object, but it doesn't have this render method. I don't believe the render method is really empty, there must be some trick here that I need to learn. What is it?

CodePudding user response：

Turns out I was misunderstood debug_backtrace(), which points me to wp-content/plugins/elementor/includes/base/controls-stack.php, but actually what gets exectued is the render method of a child object of class Controls_stack. It is indicated in the result of debug_backtrace() but I overlooked it.