Swift is technically "immutable by default" as you have to explicitly declare a variable to be mutable with `var`.
F# also is immutable by default. Maybe it's not on that "top 20" but 20 is an arbitrary cutoff. There are many so many languages being used in production that it's hard to imagine "20" is a defensible sample.
It's also hard to argue Python has any type safety with "type hints". The interpreter doesn't do anything with those hints. Linters and safety don't belong in the same sentence.
F# also is immutable by default. Maybe it's not on that "top 20" but 20 is an arbitrary cutoff. There are many so many languages being used in production that it's hard to imagine "20" is a defensible sample.
It's also hard to argue Python has any type safety with "type hints". The interpreter doesn't do anything with those hints. Linters and safety don't belong in the same sentence.
All in all, that seems like a bad source.