{# Post needs to be saved before a parent and child can be selected. #}
<div class="toolset-types-intermediary-meta-box">
    <p class="toolset-alert toolset-alert-warning">
        {{ sprintf(
            __( 'Save the post to select a <b>%s</b> and a <b>%s</b> for this intermediary post.'),
            parent_post_types_names|join(', '),
            child_post_types_names|join(', ')
        )|raw }}
    </p>
</div>