Is there a way to make this kind of type hierarchy? in this case

MutableVector2

cannot extend both

Vector2

and

MutableVector<...>

as it makes

T

conflict with itself.

Usually not. There’s a very common related issue that crops up in C++ https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern which causes a lot of problems with inheritance. The basic version of the problem looks something like:

class Foo: Bar<Foo>

and then trying to extend Foo to create Foo2 in a way that you want to it to also extend

Bar<Foo2>

which tends to lead to a bunch of problems. Thankfully this pattern is relatively rare on the JVM.

Interesting, thanks for the link