WordPress at a glance
function is not described

wp_add_trashed_suffix_to_post_name_for_post() WP 4.5.0

Adds a trashed suffix for a given post.

Store its desired (i.e. current) slug so it can try to reclaim it if the post is untrashed.

For internal use.

No Hooks.

Return

String. New slug for the post.

Usage

wp_add_trashed_suffix_to_post_name_for_post( $post );
$post(WP_Post) (required)
The post.

Code of wp add trashed suffix to post name for post: wp-includes/post.php WP 5.2.2

<?php
function wp_add_trashed_suffix_to_post_name_for_post( $post ) {
	global $wpdb;

	$post = get_post( $post );

	if ( '__trashed' === substr( $post->post_name, -9 ) ) {
		return $post->post_name;
	}
	add_post_meta( $post->ID, '_wp_desired_post_slug', $post->post_name );
	$post_name = _truncate_post_slug( $post->post_name, 191 ) . '__trashed';
	$wpdb->update( $wpdb->posts, array( 'post_name' => $post_name ), array( 'ID' => $post->ID ) );
	clean_post_cache( $post->ID );
	return $post_name;
}