+val is_unknown_id : t -> bool
+val is_unknown_type : t -> bool
+val is_wrong_type : t -> bool
+val is_wrong_number_of_args : t -> bool
+val is_invalid_syntax : t -> bool
+val is_not_a_record : t -> bool
+val is_not_an_array : t -> bool
+val is_no_such_field_in_record : t -> bool