InvalidProgramException when serializing types containing JilPrimitiveWrappers

[petersalas]

With the following types:

[JilPrimitiveWrapper]
public class JilPrimitive
{
    public readonly string Value;

    public JilPrimitive(string value)
    {
        this.Value = value;
    }
}

public class JilPrimitiveContainer
{
    public JilPrimitive Single { get; set; }
    public List<JilPrimitive> List { get; set; }
}

JSON serialization of JilPrimitiveContainer (e.g. Jil.JSON.Serialize(new JilPrimitiveContainer());) in 2.17.0 fails with a System.InvalidProgramException.