Fixes

lib/miniFun/Types.mli

@@ -34,6 +34,7 @@ val pp_type_f : type_f -> string
 type ftype = (* type used for specification *)
     IntegerType
   | BooleanType
+  | UnknownType
   | TupleType of ftype * ftype
   | FunctionType of ftype * ftype
 
@@ -92,7 +93,11 @@ type base_error = [
 type typechecking_error = [
   | base_error
   | `WrongTypeSpecification of string
-  | `RecusrionsNotImplemented of string
+]
+
+type polytypechecking_error = [
+  | typechecking_error
+  | `RecursionNotImplemented of string
 ]
 
 type error = [