for years i have searched for a usecase for recursive delegate signatures

normalizer.cs

delegate void Normalizer(object obj, Normalizer currentHead); 

private static Normalizer _normalize = (obj, currentHead) =>
{
	var type = obj.GetType();
	var normalizer = BuildNormalizeActionForObjectType(type);
	
	Normalizer newHead = (obj, futureHead) =>
	{
		if (obj.GetType() == type)
		{
			normalizer(obj);
		}
		else
		{
			currentHead(obj, futureHead);
		}
	};
	
	var foundHead = Interlocked.CompareExchange(ref _normalize, newHead, currentHead);
	if (foundHead != currentHead)
	{
    		// exchange did not occur as _normalize has been overwritten, try again from the top
		foundHead(obj, foundHead);
	}
};

public static void Normalize(object o)
{
	var n = _normalize;
	n(o, n);
}