Overridden method 'equals' has generic signature <T where T : Gradient> which is incompatible with base method's generic signature <T where T : Fill>; expected generic signature to be <T where T : Fill> <img width="768" alt="Screen Shot 2020-04-20 at 3 23 35 PM" src="https://user-images.githubusercontent.com/8112500/79724978-09cce500-831b-11ea-812c-bc0b2bda128c.png">