That's a good point, though I would argue that this is caused more by the ? in <? extends Bar> than the ? of the nullable type.

I've always found the "? extends" syntax to be confusing, and I feel like the question mark doesn't even need to be there on a syntax level. I also feel like on a language level, Java shouldn't even need a "? extends Bar", but unfortunately Java's generics system isn't strong enough to work without it.

And then it gets worse, with Foo<?> and Foo<? extends Object> being slightly different, even though it makes no sense at all.