Ticket #21290: 21290-4.diff

Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php       (revision 21544)
+++ wp-includes/query.php       (working copy)
@@ -2216,6 +2216,18 @@
                if ( $this->is_tax ) {
                        if ( empty($post_type) ) {
                                $post_type = 'any';
+
+                               // do a fully inclusive search for registered post types of queried taxonomies
+                               $tax_post_types = array();
+                               $taxonomies = wp_list_pluck( $this->tax_query->queries, 'taxonomy' );
+                               foreach ( get_post_types() as $post_type ) {
+                                       $post_type_taxonomies = get_object_taxonomies($post_type);
+                                       if ( array_intersect($taxonomies, $post_type_taxonomies) )
+                                               $tax_post_types[] = $post_type;
+                               }
+                               if ( $tax_post_types )
+                                       $post_type = $tax_post_types;
+
                                $post_status_join = true;
                        } elseif ( in_array('attachment', (array) $post_type) ) {
                                $post_status_join = true;