| rule_id | 1554 |
|---|---|
| rule_category | maintainability |
| title | Do not use optional parameters with defaults in interface methods or their concrete implementations |
| severity | 1 |
When an interface method defines an optional parameter with a default value, its default value is discarded during overload resolution unless you call the concrete class through the interface reference.
When a concrete implementation of an interface method sets a default argument for a parameter, the default value is discarded during overload resolution if you call the concrete class through the interface reference.
See the series on optional argument corner cases by Eric Lippert (part one, two, three, four) for more details.