But `f3` is different in a sense, isn't it? There we have type information propagate from a method's parameter to a method's type parameter, which is something new to Scala, isn't it? Note that I'm not against the idea, I'm just trying to understand it better!

Oh, also. Which of those are compilation errors?
```
class SomeClass
class MyClass[T <: SomeClass] 
class C[T] {
  def x: MyClass[T] = ???
}
new C[Int]
new C[SomeClass]
```