Index: src/wp-includes/class-wp-theme.php
===================================================================
--- src/wp-includes/class-wp-theme.php	(revision 46809)
+++ src/wp-includes/class-wp-theme.php	(working copy)
@@ -440,7 +440,13 @@
 	 * @return string Theme name, ready for display (translated)
 	 */
 	public function __toString() {
-		return (string) $this->display( 'Name' );
+		$response = null;
+		try {
+            $response = (string) $this->display( 'Name' );
+        } catch (Exception $e) {
+			$response = new WP_Error( 'theme_name_missing', __( $e->getMessage() ) );
+		}
+		return $response;
 	}
 
 	/**