Well I changed my mind and filed an issue anyway 
Really appreciate your time and input. Happy to work with you on this one, but right now I’m totally baffled how ReScript gets the error message SO WRONG!
4 │ let object_encode = () => dataObject_encode(Obj.magic)
This function has type ('a => JSON.t) => dataObject<'a> => JSON.t
It only accepts 2 arguments; here, it's called with more.
