1-yet-another-scala-wtf

scala> class Parent { def f = this }
defined class Parent

scala> class Child extends Parent { def newF = this }
defined class Child

scala> val c = new Child
c: Child = Child@5b966ac7

scala> c.newF
res4: Child = Child@5b966ac7

scala> c.f.newF
<console>:11: error: value newF is not a member of Parent
              c.f.newF
                  ^

2-wtf-solution

scala> class Parent { def f: this.type = this }
defined class Parent

scala> class Child extends Parent { def newF = this }
defined class Child

scala> val c = new Child
c: Child = Child@40452835

scala> c.f.newF
res7: Child = Child@40452835