using System;

using System.Reflection;

using System.Reflection.Emit;

​

public class Program

{

    public static void Main()

    {

        var assembleBuilder = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("Dynamic"), AssemblyBuilderAccess.RunAndCollect);

        var moduleBuilder = assembleBuilder.DefineDynamicModule("Dynamic.dll");

        var typeA = moduleBuilder.DefineType("classA");

        var defaultConstructorBuilder = typeA.DefineTypeInitializer(); // define static ctor

        var mpType = typeof(MessageParser<>).MakeGenericType(typeA);

        var parserFieldBuilder = typeA.DefineField("Parser", mpType, FieldAttributes.Static | FieldAttributes.Private);

        var methodInfo = typeof(Helper).GetMethod(nameof(Helper.GetDefaultMessageParser)).MakeGenericMethod(typeA);

        var ctorGenerator = defaultConstructorBuilder.GetILGenerator();

        ctorGenerator.Emit(OpCodes.Call, methodInfo);

        ctorGenerator.Emit(OpCodes.Stsfld, parserFieldBuilder);

        ctorGenerator.Emit(OpCodes.Ret);

        var type = typeA.CreateType();

        var instance = Activator.CreateInstance(type);

        var value = type.GetField("Parser", BindingFlags.Static | BindingFlags.NonPublic)?.GetValue(new object[]{});

        Console.WriteLine(value?.ToString()); // prints MessageParser`1[classA]

    }

}

​

public class Helper

{

    public static MessageParser<T> GetDefaultMessageParser<T>()

        where T : new() => new MessageParser<T>(() => new T());

}

​

public class MessageParser<T>

{

    public MessageParser(Func<T> func)

    {

    }

}