Scala Function Variance and Overriding

Question

I\'m having a little problem understanding variance of methods when overloading.

While this perfectly works due to covariance in the return type

class Bl         


        

Answer 1

Well in your second example the signature of tester() in Test declares a Fasel argument but with the overriden signature of FooTest tester() is declared with a Bla as argument. Since Fasel is a subtype of Bla by their extends hierarchy this is probably wrong.