Autofac question

program.cs

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using System.Xml;
using Autofac;

namespace AutofacTest
{
    /// <summary>
    /// Attribute that marks parameters that must be given by hand.
    /// </summary>
    public class ParameterAttribute : Attribute { }
    
    /// <summary>
    /// just an item that should never be resolved
    /// </summary>
    public struct DataItem
    {
        public string Content { get; set; }
    }
    
    public interface IImportXml
    {
        IEnumerable<DataItem> ImportData();
    }

    public class ImportXml : IImportXml
    {
        public ImportXml(
            Func<string, XmlReader> readerForFile, // to be resolved
            [Parameter] XmlSettings settings) // to be defined manually
        {
        }
        
        public IEnumerable<DataItem> ImportData()
        {
            yield break;
        }
    }
    
    public interface IImportData{}

    public class SettingsAgnosticImportXml : IImportData
    {
        public SettingsAgnosticImportXml(
            Func<string, XmlReader> readerForFile, // to be resolved
            XmlSettings settings) // to be resolved, too!
        {
        }
    }
    
    public class XmlSettings
    {
        public Encoding RequiredEncoding { get; set; }
    }

    public interface IDecodeXml
    {
        IEnumerable<DataItem> ReadFile(XmlSettings settings);
    }

    public class AutofacTest
    {
        private readonly IImportXml import;

        public AutofacTest(IImportXml import)
        {
            this.import = import;
        }

        public void DecodeXml(string filename)
        {
            this.import.ImportData();
        }
        
        public static void Main(string[] args) 
        {
            var builder = new ContainerBuilder();
            
            builder.Register<Func<string, XmlReader>>(context => s => XmlReader.Create(s))
                .SingleInstance();
            
            builder
                .RegisterAssemblyTypes(Assembly.GetAssembly(typeof(AutofacTest)))
                .AsImplementedInterfaces()
                .AsSelf();
            var container = builder.Build();
            

            // should be possible:
            var getInstance = container.Resolve<Func<XmlSettings, AutofacTest>>();
            getInstance(new XmlSettings())
                .DecodeXml("testfile.xml");
            
            // should not be possible, as XmlSettings get auto-resolved here:
            var instance = container.Resolve<AutofacTest>();

            // should be possible (although there's an XmlSettings parameter involved):
            var agnostic = container.Resolve<IImportData>();
            
            instance.DecodeXml("testfile.xml");
        }
    }
}