Ensure-different compares value-or-values-1 value-or-values-2 or each value of value-or-values-1 and value-or-values-2 (if they are multiple values) using test. If any comparison returns true, then ensure-different raises a warning which uses report as a format string and arguments as arguments to that string (if report and arguments are supplied). If ensure-different is used within a test, a test failure is generated instead of a warning