I received the below while creating a new calculated question from the question bank. This came up while testing MDL-37932.

( ! ) Warning: Creating default object from empty value in /home/andrew/Desktop/code/moodle/int/master/question/type/calculated/questiontype.php on line 1640
Call Stack

1. Time Memory Function Location
   1 0.0013 361992 {main}( ) ../question.php:0
   2 0.4080 25132208 question_type->create_editing_form( ) ../question.php:200
   3 0.4142 25744864 qtype_calculated_edit_form->__construct( ) ../questiontypebase.php:217
   4 0.4143 25745120 question_edit_form->__construct( ) ../edit_calculated_form.php:67
   5 0.4151 25747344 moodleform->moodleform( ) ../edit_question_form.php:113
   6 0.4186 25832680 question_edit_form->definition( ) ../formslib.php:191
   7 0.4355 26924792 qtype_calculated_edit_form->definition_inner( ) ../edit_question_form.php:204
   8 0.4368 26983152 qtype_calculated->print_dataset_definitions_category( ) ../edit_calculated_form.php:114
   
   ( ! ) Warning: Creating default object from empty value in /home/andrew/Desktop/code/moodle/int/master/question/type/calculated/questiontype.php on line 1640
   Call Stack
   # Time Memory Function Location
   1 0.0013 361992 {main}

   ( ) ../question.php:0
   2 0.4080 25132208 question_type->create_editing_form( ) ../question.php:200
   3 0.4142 25744864 qtype_calculated_edit_form->__construct( ) ../questiontypebase.php:217
   4 0.4143 25745120 question_edit_form->__construct( ) ../edit_calculated_form.php:67
   5 0.4151 25747344 moodleform->moodleform( ) ../edit_question_form.php:113
   6 0.4186 25832680 question_edit_form->definition( ) ../formslib.php:191
   7 0.4355 26924792 qtype_calculated_edit_form->definition_inner( ) ../edit_question_form.php:204
   8 0.4368 26983152 qtype_calculated->print_dataset_definitions_category( ) ../edit_calculated_form.php:114