non_nullable_equals_parameter

The parameter type of '==' operators should be non-nullable.

The analyzer produces this diagnostic when an override of the operator == has a parameter whose type is nullable. The language spec makes it impossible for the argument of the method to be null, and the parameter's type should reflect that.

The following code produces this diagnostic because the implementation of the operator == in C :

class C {
  @override
  bool operator ==(Object? other) => false;
}

Make the parameter type be non-nullable:

class C {
  @override
  bool operator ==(Object other) => false;
}