Example of Inference Working.dart

typedef T2 Adder<T1, T2>(T1 left, T1 right);

class AddMachine<A> {
  A left;
  A right;
  
  AddMachine(this.left, this.right);
  
  B Sum<B>(Adder<A, B> adder) {
    print([A, B]);
    print(adder.runtimeType);
    return adder(left, right);
  }
}

void main() {
  var a = 1;
  var b = 2;
  
  var machine = AddMachine(a, b);
  var result = machine.Sum((a, b) => a.toString() + b.toString());
  print(result);
}