First I would state that in most cases the query_posts
should be avoided!
This function will completely override the main query and isn’t
intended for use by plugins or themes. Its overly-simplistic approach
to modifying the main query can be problematic and should be avoided
wherever possible.
I would suggest transfer your query with WP_Query and try something like this:
$all_prods = array(
'posts_per_page' => -1,
'post_type' => 'product',
);
$query = new WP_Query($all_prods);
while ($query->have_posts()) {
$query->the_post();
$post_id = get_the_ID();
echo $post_id;
}
For the Debug part, I would use the get_post($post_id);
to verify that we talk about the same post_type.