type classes sort of solve the same problem and in both rust and haskell they can sort of emulate union types (I have no idea about the details, I am not an exp

type classes sort of solve the same problem and in both rust and haskell they can sort of emulate union types (I have no idea about the details, I am not an expert of subtyping). Still the usability feature of being able to quickly create arbitrary union types is undeniable (Julia uses something similar as a main source of polymorphism and personally I think it is amazing)