prerequisite :

• a taskchain activity is created
• some attempts are recorded

steps to reproduce :

• in the navigation menu, expand the 'Class reports' node of the taskchain activity
• click on the 'Chain grades' link
• in the table, click on the score of the column 'Attempt grade'
• in the new table, click on the score of the column 'Score'
• check in the breadcrumb that you are on the Taskscore screen
• in the navigation menu, expand the 'Class reports' node of the taskchain activity, you should see an Item analysis option
• click on this link

What you should get :

• the corresponding screen should be displayed

What you get :

• the following error message :

Fatal error: Call-time pass-by-reference has been removed in ./report/taskanalysis/renderer.php on line 61

I've provided a fix for this issue on github and have generated a pullrequest.
Once this error is fixed, you run into the following error :

Debug info: Argument 4 passed to table_sql::set_sql() must be of the type array, string given, called in /home/moodle/plugins/mod/taskchain/report/renderer.php on line 185 and defined
Error code: codingerror
Stack trace:
line 406 of /lib/setuplib.php: coding_exception thrown
line 1365 of /lib/tablelib.php: call to default_error_handler()
line 185 of /home/moodle/plugins/mod/taskchain/report/renderer.php: call to table_sql->set_sql()
line 110 of /home/moodle/plugins/mod/taskchain/report/renderer.php: call to mod_taskchain_report_renderer->reportcontent()
line 95 of /home/moodle/plugins/mod/taskchain/report.php: call to mod_taskchain_report_renderer->render_report()

The problem comes form the order of the elements in the returned array of the method mod_taskchain_report_renderer::select_sql.
In all uses and all the overridings of this method I've found, the $params array is in fourth position, not in fifth.