public void Unify_TwoSubtypes_DoesNotUnify()
{
var tags2double = new Curry(Typs.Tags, Typs.Double);
var tags2pdouble = new Curry(Typs.Tags, Typs.PDouble);
var unifA = tags2double.Unify(tags2pdouble, true);
Assert.Null(unifA);
var unifB = tags2pdouble.Unify(tags2double, true);
Assert.NotNull(unifB);
var unifC = tags2double.Unify(tags2pdouble, false);
Assert.NotNull(unifC);
var unifD = tags2pdouble.Unify(tags2double, false);
Assert.Null(unifD);
}