The fromReflection method tries to set the implemented interfaces on the new instance directly from the reflection's getInterfaces() method. However the setImplementedInterfaces() method expects an array of strings, and Zend_Reflection_Class::getInterfaces() returns an array of Zend_Reflection_Class. Also, the array_diff for discarding interfaces implemented by the parent class is the wrong way round. It should be array_diff($reflectionClass..., $parentClass...) Suggest the changes supplied in the attached patch