Custom Post Type & Custom Menu Walker to append custom class for active post types

When i want to add the classes current-menu-item and current-page-ancestor i always use the wp_nav_menu without any custom walker. I only build my own walker if i want to change lets say the classes to something like “sel” instead.

So i add the menu like this:

<?php
  wp_nav_menu( 
    array(
    'theme_location' => 'company-menu',
    'container' => false,
    'menu_class' => '',
    'echo' => true,
    'before' => '',
    'after' => '',
    'link_before' => '',
    'link_after' => '',
    'depth' => 2,
    'items_wrap' => '<ul id="company-right-menu">' . "\n" . '%3$s</ul>' . "\n"
    )
  );
?> 

And then i add this action to my functions.php file:

function additional_active_item_classes($classes = array(), $menu_item = false){
    global $wp_query;

    if( in_array('current-menu-item', $menu_item->classes) ){
        $classes[] = 'current-menu-item';
    }

    // add class current-menu-item to archive
    if ( $menu_item->post_name == 'my_custom_post' && is_post_type_archive('my_custom_post') ) {
        $classes[] = 'current-menu-item';
    }

    // add class current-menu-item to single
    if ( $menu_item->post_name == 'my_custom_post' && is_singular('my_custom_post') ) {
        $classes[] = 'current-menu-item';
    }


    return $classes;
}
add_filter( 'nav_menu_css_class', 'additional_active_item_classes', 10, 2 );

If this is in the right direction i can help you more if you want.