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;