It's not possible to serialize derrived type without any parameters

[nicloay]

If I have 2 types like Type1 and Type2 which implement a common interface it's not possible to deserialize document if one of them has no extra parameters

list:
  - !type1
    param: 9999
  - !type2
  - !type1
    param: 3333

as type2 doesn't have parameter the result list will have only 2 elements of type1

[hadashiA]

I tried the following test, which passed: the number of elements in the list is 3.

BTW, - !type2 this is included in the list as null. Using - !type2 {} will produce an intance.

        [Test]
        public void Deserialize_UnionFromEmptyElement()
        {
            var result = Deserialize<Dictionary<string, IEmpty[]>>(
                "list:\n" +
                "  - !impl1\n" +
                "    a: 9999\n" +
                "  - !impl2\n" +
                "  - !impl1\n" +
                "    a: 3333");

            Assert.That(result.Count, Is.EqualTo(1));
            Assert.That(result["list"].Length, Is.EqualTo(3));
        }

    [YamlObject]
    [YamlObjectUnion("!impl1", typeof(EmptyInterfaceImpl1))]
    [YamlObjectUnion("!impl2", typeof(EmptyInterfaceImpl2))]
    public partial interface IEmpty
    {
    }

    [YamlObject]
    public partial class EmptyInterfaceImpl1 : IEmpty
    {
    }

    [YamlObject]
    public partial class EmptyInterfaceImpl2 : IEmpty
    {
    }