>>>
class MyClassLongName {
    MyClassLongName(Argument arg1, Argument arg2, Argument arg3) :
      super.con1(arg1, arg2, arg3,
          namedArgument: (r) => new FooClassLongName(r));
}

class MyClassVeryVeryLongName {
    MyClassVeryVeryLongName(
        Argument arg1, Argument arg2, Argument arg3, Argument arg4)
      : super.con1(arg1, arg2, arg3,
          namedArgument: (r) => new FooClassLongName(r));
}
<<<
class MyClassLongName {
  MyClassLongName(Argument arg1, Argument arg2, Argument arg3)
    : super.con1(
        arg1,
        arg2,
        arg3,
        namedArgument: (r) => new FooClassLongName(r),
      );
}

class MyClassVeryVeryLongName {
  MyClassVeryVeryLongName(
    Argument arg1,
    Argument arg2,
    Argument arg3,
    Argument arg4,
  ) : super.con1(
        arg1,
        arg2,
        arg3,
        namedArgument: (r) => new FooClassLongName(r),
      );
}