I have the following classes defined (code redacted for brevity)

public interface ICollectionItem
{}

Which in turn is inherited by:

public class CollectionItem : NotifyPropertyChanged, ICollectionItem
{}

And in turn is inherited by:

public class DeviceItem : CollectionItem, IDisposable, IAsyncDisposable
{
    public DeviceItem(DeviceCollectionBase<ICollectionItem> deviceCollection)
    {}
}

Which has a constructor so i can then create a DeviceItem instance from within yet another class:

public abstract class DeviceCollectionBase<T> : PacedItemCollection<T>, IDisposable, IAsyncDisposable where T : ICollectionItem
{
    
    protected override async Task UpdateCollection()
    {
        var v = new DeviceItem(this)...
    }
}

But the parameter this is flagged with the error CS1503 "Argument type DeviceCollectionBase<T>, is not assignable to parameter type DeviceCollectionBase<ICollectionItem> , yet T is constrained to be an ICollectionItem.

So here we have the parameter definition asking for an ICollectionItem and the parameter passed implementing from an ICollectionItem

My covariance and/or contravariance games are shite, so i don’t quite see where im going wrong, nor how to work around the issue, any help please?