Bug in Autofac MEF integration: Instantiates component when only querying for metadata

Question

There appears to be a bug in how Autofac handles service instantiation when integrating with MEF

The following test show that MEF does not instantiate the services before it have to. (In this case, I'm only querying for metadata)

[TestMethod]
public void Mef_DoesNotInstantiateService_WhenOnlyQueryingForMetadata()
{
    var aggregateCatalog = CreateMefCatalog();
    var container = new CompositionContainer(aggregateCatalog, true);

    var serviceConsumer = container.GetExportedValue<ServiceConsumer>();

    serviceConsumer.Services.Any(x => x.Metadata.Name == "Service1").Should().BeTrue();
}

The following test is failing, since Autfac is trying to create an instance of Service1 - which throws an exception in the constructor.

[TestMethod]
public void Autofac_DoesNotInstantiateService_WhenOnlyQueryingForMetadata()
{
    var aggregateCatalog = CreateMefCatalog();

    var builder = new ContainerBuilder();
    builder.RegisterComposablePartCatalog(aggregateCatalog);
    var container = builder.Build();

    //Next line will throw an exception. (Autofac is instantiating the service, but should not)
    var serviceConsumer = container.Resolve<ServiceConsumer>();

    //Note: This test will never get here..
    serviceConsumer.Services.Any(x => x.Metadata.Name == "Service1").Should().BeTrue();
}

Other code required by the tests

static AggregateCatalog CreateMefCatalog()
{
    return new AggregateCatalog(new List<ComposablePartCatalog>
    {
        new AssemblyCatalog(Assembly.GetExecutingAssembly())
    });
}

[Export]
class ServiceConsumer
{
    [ImportMany]
    public IEnumerable<Lazy<IService, INameMetadata>> Services { get; set; }
}


public interface IService { }

[Export(typeof (IService))]
[ExportMetadata("Name", "Service1")]
public class Service1 : IService
{
    public Service1()
    {
        throw new Exception("This service should never be created");
    }
}

public interface INameMetadata
{
    string Name { get; }
}

BTW: I'm using the currently stable versions: Autofac 3.5.2 and Autofac.Mef 3.0.3