The title is a bit clickbait, as the article isn't saying that statically typed languages don't leak data, they are instead showing a hypothetical language whic

The title is a bit clickbait, as the article isn't saying that statically typed languages don't leak data, they are instead showing a hypothetical language which has a special type checker where types also encode privacy levels and the type checker asserts at compile time that no variable of a higher privacy type is assigned to a variable of a lower privacy type (amongst other things). The article is really talking about research advancement in information flow control checks at compile time using advanced type systems, and no real language.