ToSingleton() with resolutionMode=RETURN_NULL throws exception

[FodderMK]

Using Adic 2.20.1 the following code:

public class Test1 {
    [Inject] public Test2 Foo;
}

public class Test2 {
    public string Bar = "Bar";
}

public class GameRoot : ContextRoot {
  public override void SetupContainers() {
    var container = this.AddContainer<InjectionContainer>();
    container.resolutionMode = ResolutionMode.RETURN_NULL;
    container.Bind<Test2>().ToSingleton();
    container.Bind<Test1>().ToSingleton();
  }
}

throws the following exception on the container.Bind<Test1>().ToSingleton() line:

NullReferenceException: Object reference not set to an instance of an object
Adic.Injection.Injector.OnBeforeAddBinding (IBinder source, Adic.Binding.BindingInfo& binding) (at Assets/Adic/Scripts/Framework/Injection/Injector.cs:517)
Adic.Binding.Binder.AddBindingToDictionary (Adic.Binding.BindingInfo binding) (at Assets/Adic/Scripts/Framework/Binding/Binder.cs:71)
Adic.Binding.Binder.AddBinding (Adic.Binding.BindingInfo binding) (at Assets/Adic/Scripts/Framework/Binding/Binder.cs:62)
Adic.Binding.BindingFactory.AddBinding (System.Object value, BindingInstance instanceType) (at Assets/Adic/Scripts/Framework/Binding/BindingFactory.cs:178)
Adic.Binding.BindingFactory.ToSingleton () (at Assets/Adic/Scripts/Framework/Binding/BindingFactory.cs:38)
GameRoot.SetupContainers () (at Assets/_/Scripts/GameRoot.cs:36)
Adic.ContextRoot.Awake () (at Assets/Adic/Scripts/Extensions/ContextRoot/ContextRoot.cs:69)

If I change the ToSingleton() methods to ToSelf() OR if I change the resolution mode to ALWAYS_RESOLVE then the bindings work correctly.

[intentor]

Thanks for the feedback! I'll look into it and release a fix on the next version!