Closed
Description
When defining a named argument with a non-nullable type and no default you are required to add the required keyword.
This appears to be redundant.
From the diagnostics page:
missing_default_value_for_parameter
The parameter ‘{0}’ can’t have a value of ‘null’ because of its type, but the implicit default value is ‘null’.
Description
The analyzer produces this diagnostic when an optional parameter, whether positional or named, has a potentially non-nullable type and doesn’t specify a default value. Optional parameters that have no explicit default value have an implicit default value of null. If the type of the parameter doesn’t allow the parameter to have a value of null, then the implicit default value isn’t valid.
I've identified five use patterns for named arguments:
abstract class test {
void one({required String name});
void two({String name = 'hi'});
void three({String? name});
void four({String? name = 'hi'});
void five({required String? name});
}The option for required with pattern five makes sense, the requirement on one appears to be redundant.
Given most of my usage of named arguments is for non-nullable types this redundant requirement is somewhat annoying.
It would appear that we could remove this requirement and provide a lint to advise that it can be removed.
I don't think this would require any migration as it simply becomes optional.