flutter custom annotation like Required - flutter

Question

what I want is an annotation like #required but I want to do some logic based on the type of parameter and show the use a warning like what #required does.
(if type is ParamTuple shows the warning)
abstract class Tuple {
const Tuple();
}
abstract class NullTuple extends Tuple {
const NullTuple();
}
abstract class ParamTuple extends Tuple {
const ParamTuple();
}
I want to warn user if the type is ParamTuple but in other cases I don't want warning.
In the code below, the logic should be implemented
const TupleRequired tupleRequired = TupleRequired();
class TupleRequired {
const TupleRequired();
}
also I think that I should add an analysis_options.yaml to show warning like #required for my #tupleRequired.
EXAMPLE OF WHAT I WANT
class Example {
// Tuple0 extends NullTuple
void nullParam({#tupleRequired Tuple0 param}) {}
// Tuple1 extends ParamTuple
void withParam({#tupleRequired Tuple1 param}) {}
}
so when we want to use these methods, I want to see the below custom warning:
nullParam : if I put it empty , shows nothing but if I pass an argument shows the argument is redundant and will be ignored
withParam : if I put it empty , shows warning to pass argument and if I pass an argument shows nothing

Answer 1

In the constructor You can use assert like:
class TupleRequired {
final Tuple touple;
TupleRequired(this.touple): assert(touple is! ParamTuple);
}
in dart is/is! checks if an object is of specific type like for example
var s = 'this is a string type';
print(s is String); // prints true because s is string
print(s is! int); // prints true because s is not an int