Daniel Westheide is a software engineer living in Berlin, Germany. He is a senior consultant at INNOQ and co-organiser of ScalaBridge Berlin, the Berlin chapter of the ScalaBridge organisation.

He cares about empathy and inclusivity, and about the ethical, social, and ecological consequences of his work. He is the author of The Neophyte’s Guide to Scala. Recently, he published a new book for Scala beginners, Scala from Scratch: Exploration.

The trouble with subtyping: An introduction to typebounds and variance

Many people come to Scala from object-oriented languages with class-based inheritance. Nevertheless the complexity inherent in subtyping is often one of the biggest hurdles for them. In this talk I will explain type bounds, covariance, and contravariance from the ground up.