Source

File: wp-includes/comment.php

function update_comment_cache( $comments, $update_meta_cache = true ) {
	foreach ( (array) $comments as $comment ) {
		wp_cache_add( $comment->comment_ID, $comment, 'comment' );
	}

	if ( $update_meta_cache ) {
		// Avoid `wp_list_pluck()` in case `$comments` is passed by reference.
		$comment_ids = array();
		foreach ( $comments as $comment ) {
			$comment_ids[] = $comment->comment_ID;
		}
		update_meta_cache( 'comment', $comment_ids );
	}
}