the_widget( string $widget, array $instance = array(), array $args = array() )

function the_widget( $widget, $instance = array(), $args = array() ) {
	global $wp_widget_factory;

	if ( ! isset( $wp_widget_factory->widgets[ $widget ] ) ) {
		/* translators: %s: register_widget() */
		_doing_it_wrong( __FUNCTION__, sprintf( __( 'Widgets need to be registered using %s, before they can be displayed.' ), '<code>register_widget()</code>' ), 'WP-4.9.0' );
		return;
	}

	$widget_obj = $wp_widget_factory->widgets[$widget];
	if ( ! ( $widget_obj instanceof WP_Widget ) ) {
		return;
	}

	$default_args = array(
		'before_widget' => '<div class="widget %s">',
		'after_widget'  => "</div>",
		'before_title'  => '<h2 class="widgettitle">',
		'after_title'   => '</h2>',
	);
	$args = wp_parse_args( $args, $default_args );
	$args['before_widget'] = sprintf( $args['before_widget'], $widget_obj->widget_options['classname'] );

	$instance = wp_parse_args($instance);

	/**
	 * Fires before rendering the requested widget.
	 *
	 * @since WP-3.0.0
	 *
	 * @param string $widget   The widget's class name.
	 * @param array  $instance The current widget instance's settings.
	 * @param array  $args     An array of the widget's sidebar arguments.
	 */
	do_action( 'the_widget', $widget, $instance, $args );

	$widget_obj->_set(-1);
	$widget_obj->widget($args, $instance);
}