diff --git a/wp-includes/template.php b/wp-includes/template.php
index 01f9c8a715..cc15eedb48 100644
--- a/wp-includes/template.php
+++ b/wp-includes/template.php
@@ -135,8 +135,9 @@ function get_post_type_archive_template() {
 		$post_type = reset( $post_type );
 
 	$obj = get_post_type_object( $post_type );
-	if ( ! $obj->has_archive )
+	if ( ! ( $obj instanceof WP_Post_Type ) || ! $obj->has_archive ) {
 		return '';
+	}
 
 	return get_archive_template();
 }
diff --git a/wp-includes/version.php b/wp-includes/version.php
index b99db66045..770f018f15 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-40030';
+$wp_version = '4.8-alpha-40031';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.