add_shortcode inside widget

function thumbpost_list_shortcode($atts){
    extract( shortcode_atts( array(
        'count' => 3,
    ), $atts) );
     
    $q = new WP_Query(
        array('posts_per_page' => $count, 'post_type' => 'post')
        );      
         
    $list = '<ul>';
    while($q->have_posts()) : $q->the_post();
        $idd = get_the_ID();
        $list .= '
        <li>
		<img src="<?php echo get_template_directory_uri(); ?>/assets/img/latest-post/1.png" alt="" />
		'.get_the_post_thumbnail($idd,'thumbnail').'
		<p><a href="'.get_permalink().'">'.get_the_title().'</a></p>
		<span>'.get_the_date('d F Y', $idd ).'</span>
		</li>
        ';        
    endwhile;
    $list.= '</ul>';
    wp_reset_query();
    return $list;
}
add_shortcode('latest_post', 'thumbpost_list_shortcode');