PHP ReflectionClass method does not exists

I am trying to instantiate a class by reflection like this:

$class = new ReflectionClass('App\\Widgets\\TestWidget');

But that always throws a ReflectionException with this message:

[2017-02-20 19:05:25] local.ERROR: ReflectionException while trying to reflect C:\Users\Asier\PhpstormProjects\web-cms\app\Widgets\TestWidget\TestWidget.php

Class App\Widgets\TestWidget implements Widget {

/**
 * It is called when the widget is used in a template to render it.
 * @return string
 */
public function render() {
    return "Hello world from TestWidget";
}

/**
 * Returns the widget's name
 * @return string
 */
public static function getWidgetName() {
    return "TestWidget";
}

/**
 * Returns the widget's info
 * @return string|array
 */
public static function getWidgetInfo() {
    return "";
}

/**
 * It is called when the widget is uploaded to make the proper setup for it if needed
 * @return void
 */
public static function setup() {

}

// POR ALGUN MOTIVO EL ULTIMO METODO SIEMPRE ME DICE QUE NO EXISTE

public function dummy() does not exist

And this is the class:

<?php
namespace App\Widgets;


class TestWidget implements Widget {

/**
 * It is called when the widget is used in a template to render it.
 * @return string
 */
public function render() {
    return "Hello world from TestWidget";
}

/**
 * Returns the widget's name
 * @return string
 */
public static function getWidgetName() {
    return "TestWidget";
}

/**
 * Returns the widget's info
 * @return string|array
 */
public static function getWidgetInfo() {
    return "";
}

/**
 * It is called when the widget is uploaded to make the proper setup for it if needed
 * @return void
 */
public static function setup() {

}

public function dummy() {}

}

If I delete the last method (dummy), then it says the same "does not exists" with the last method in the class.

Any ideas?