Mono Generic Constraint Bug?

MonoGenericWeirdness.cs

	public abstract class ThingWithOrganizationId
	{
		public Guid OrganizationId;
	}

	public class Thing : ThingWithOrganizationId
	{
	}

	public abstract class  BaseService<TConstraint> 
	{
		public abstract void Save<T> (T newView) where T : TConstraint;
	}

	public class DerivedService:BaseService<Thing>
	{
		public override void Save<TThing>(TThing newView)
		{
			Console.WriteLine(newView.OrganizationId);
		}
	}

error CS1061: Type TThing' does not contain a definition forOrganizationId' and no extension method OrganizationId' of typeTThing' could be found. Are you missing an assembly reference?