So he's saying he rejected declarations that allow you to declare either nullable or non-nullable types?
Kotlin and Rust seem to have an interesting approach. In Kotlin, you have to explicitly declare nullable types, and Rust does not allow references/pointers to be null in the first place if I am not mistaken. I have just recently started learning more about Scala, and although it allows nulls to be passed, they are not idiomatic, and I am guessing it would not be too hard to have an automatic style checker that catches uses of null (at least those that do not interface to Java libraries).
Kotlin and Rust seem to have an interesting approach. In Kotlin, you have to explicitly declare nullable types, and Rust does not allow references/pointers to be null in the first place if I am not mistaken. I have just recently started learning more about Scala, and although it allows nulls to be passed, they are not idiomatic, and I am guessing it would not be too hard to have an automatic style checker that catches uses of null (at least those that do not interface to Java libraries).