YamlDotNet is not parsing anchors correctly

[darkguy2008]

Describe the bug
Objects referencing anchors come out as null.

To Reproduce

using System.IO;
using YamlDotNet.Core;
using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;

namespace compiler
{
    class Program
    {
        static void Main(string[] args)
        {
            string yaml = @"
controls:
  - control: &panel1
    type: panel
    background: red

  - control: &panel2
    type: panel
    background: blue

structure:
  - *panel1
  - *panel2
            ";
            var ds = new DeserializerBuilder()
                .WithNamingConvention(CamelCaseNamingConvention.Instance)
                .IgnoreUnmatchedProperties()
                .Build();
            var f = ds.Deserialize<object>(
                new MergingParser(new Parser(new StringReader(yaml))));
        }
    }
}

Result: Structure items are null:

Changing the structure to:

structure:
  - <<: *panel1
  - <<: *panel2

Throws an exception:

Exception has occurred: CLR/System.Collections.Generic.KeyNotFoundException
An unhandled exception of type 'System.Collections.Generic.KeyNotFoundException' occurred in System.Private.CoreLib.dll: 'The given key 'panel1' was not present in the dictionary.'
   at System.ThrowHelper.ThrowKeyNotFoundException[T](T key)
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at YamlDotNet.Core.MergingParser.ParsingEventCollection.FromAnchor(AnchorName anchor)
   at YamlDotNet.Core.MergingParser.GetMappingEvents(AnchorName anchor)
   at YamlDotNet.Core.MergingParser.HandleAnchorAlias(LinkedListNode`1 node, LinkedListNode`1 anchorNode, AnchorAlias anchorAlias)
   at YamlDotNet.Core.MergingParser.HandleMerge(LinkedListNode`1 node)
   at YamlDotNet.Core.MergingParser.Merge()
   at YamlDotNet.Core.MergingParser.MoveNext()
   at YamlDotNet.Core.ParserExtensions.Accept[T](IParser parser, T& event)
   at YamlDotNet.Core.ParserExtensions.TryConsume[T](IParser parser, T& event)
   at YamlDotNet.Serialization.Deserializer.Deserialize(IParser parser, Type type)
   at YamlDotNet.Serialization.Deserializer.Deserialize[T](IParser parser)

Expected result

Structure should contain the same items shown in the Controls key in the screenshot above.

[EdwardCooke]

This makes sense. The anchor is set to the content of control. Which is empty. And according to yaml spec, empty means null.

The following YAML:

controls:
  - control: &panel1 hello1
    type: panel
    background: red

  - control: &panel2 hello2
    type: panel
    background: blue

structure:
  - *panel1
  - *panel2

Looks like this:

The following yaml

controls:
  - &panel1
    control: hello1
    type: panel
    background: red

  - &panel2
    control: hello2
    type: panel
    background: blue

structure:
  - *panel1
  - *panel2

looks like this:

I'm going to close this issue. If you need more assistance, or disagree, feel free to reopen it.