The null thing is a bad example, particularly because it's from the .NET side and C# is focusing on removing that now through nullable reference types, but I'm honestly surprised they claimed F# has a better type system.
F# lacks functors, first class modules, row polymorphism, GADTs, PPX extensions, and likely some others I'm not aware of. GADTs, row polymorphism, and PPX extensions I've wished for in particular because they solve some problems I frequently run into with MVU/Elmish architecture on the front end.
F# instead has inline functions with static constraints (similar to C++ templates), type providers, computation expressions, and units of measure.
F# lacks functors, first class modules, row polymorphism, GADTs, PPX extensions, and likely some others I'm not aware of. GADTs, row polymorphism, and PPX extensions I've wished for in particular because they solve some problems I frequently run into with MVU/Elmish architecture on the front end.
F# instead has inline functions with static constraints (similar to C++ templates), type providers, computation expressions, and units of measure.