I do not remember any OCaml and I get an error when trying to run it (File "./test.ml", line 123, characters 6-7: Error: Syntax error: operator expected.) so I do not know if I can be of much help. What is the result of typ_of_expr [] (app k_intint (Int 1))? I presume that you expect it to be IntTy -> IntTy, right?
Just fyi, this is called System F.
I do not remember any OCaml and I get an error when trying to run it (File "./test.ml", line 123, characters 6-7: Error: Syntax error: operator expected.) so I do not know if I can be of much help. What is the result of typ_of_expr [] (app k_intint (Int 1))? I presume that you expect it to be IntTy -> IntTy, right?