cannot serialize internal class?

[itn3000]

Environment

MessagePack assembly version is 1.0.1

here is dotnet --info output

.NET Command Line Tools (1.0.1)

Product Information:
 Version:            1.0.1
 Commit SHA-1 hash:  005db40cd1

Runtime Environment:
 OS Name:     ubuntu
 OS Version:  16.04
 OS Platform: Linux
 RID:         ubuntu.16.04-x64
 Base Path:   /usr/share/dotnet/sdk/1.0.1

Steps to reproduce

compile the following source and run with dotnet run

using System;

namespace msgpack_cli_test
{
    using MessagePack;
    // if this class is public struct, success
    [MessagePackObject]
    struct TestObject
    {
        [Key(0)]
        public int A{get;set;}
        [Key(1)]
        public string B{get;set;}
    }
    class Program
    {
        static void Main(string[] args)
        {
            var obj  = new TestObject()
            {
                A = 100,
                B = "piyopiyo"
            };
            var data = MessagePackSerializer.Serialize(obj);
            Console.WriteLine($"{data.Length}");
            var x = MessagePackSerializer.Deserialize<TestObject>(data);
            Console.WriteLine($"{x.A}");
        }
    }
}

Expected Behavior

output two digits then exit 0

Actual Behavior

output following exception message

Unhandled Exception: System.TypeLoadException: Type 'MessagePack.Formatters.msgpack_cli_test_TestObjectFormatter' from assembly 'MessagePack.Resolvers.DynamicObjectResolver, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' is attempting to implement an inaccessible interface.
   at MessagePack.FormatterResolverExtensions.GetFormatterWithVerify[T](IFormatterResolver resolver)
   at MessagePack.MessagePackSerializer.Serialize[T](T obj, IFormatterResolver resolver)
   at msgpack_cli_test.Program.Main(String[] args) in /home/malion/src/msgpack-cli-test/Program.cs:line 23

[neuecc]

Yes.
This is assembly builder limitation.
https://msdn.microsoft.com/en-us/library/system.reflection.emit.assemblybuilder(v=vs.110).aspx

MessagePack for C# create assembly per resolver and create dynamic formatter per resolver.

var t = DynamicObjectResolver.Instance.GetFormatter<TestObject>();

// MessagePack.Formatters.TestObjectFormatter
Console.WriteLine(t.GetType().FullName);

// MessagePack.Resolvers.DynamicObjectResolver, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null
Console.WriteLine(t.GetType().Assembly.FullName);

Created assembly is same as standard assembly so can not access external internal type.

Note: But I should output more informational exception message.

[itn3000]

Thank you for response,I understand.
I think it's better adding this limitation in README, how about it?

[neuecc]

Thank you, I've added it.
and I'll add varidate and throw informational exception.

[itn3000]

Great thanks.
Should I close this issue, or leave for fix?

[neuecc]

Thanks, closed.

[asyncx]

I don't know if this has been mentioned but you can workaround if you add the following lines to your project

[assembly: InternalsVisibleTo("MessagePack")]
[assembly: InternalsVisibleTo("MessagePack.Resolvers.DynamicObjectResolver")]
[assembly: InternalsVisibleTo("MessagePack.Resolvers.DynamicUnionResolver")]

This way MessagePack.Resolvers.DynamicObjectResolver will be able to access your internal types and avoid the "attempting to implement an inaccessible interface" error.