In 'section_edit_control_menu' there is the line:

                $attr = empty($value['attr']) ? '' : $value['attr'];

if the caller of this method has no 'attr' value in the supplied control, then the 'action_menu_link_secondary' constructor will fail with 'Argument 4 passed to action_menu_link_secondary::__construct() must be of the type array, string given, called in [dirroot]\course\format\renderer.php on line 115'.

Such as with an input control of:

                $controls[] = html_writer::link($url, html_writer::empty_tag('img',

                                    array('src' => $this->output->pix_url('i/marker'),

                                          'class' => 'icon', 'alt' => $markthistopic)),

                                    array('title' => $markthistopic,

                                          'class' => 'editing_highlight'));

Which I realise is what it used to be, however, there is still this possibility and the core code to code method call is logically wrong.

Therefore the code needs to be:

                $attr = empty($value['attr']) ? array() : $value['attr'];