type constant = | Const_int of int| Const_char of char| Const_string of string * Location.t * string option| Const_float of string| Const_int32 of int32| Const_int64 of int64| Const_nativeint of nativeint
type rec_flag = | Nonrecursive| Recursive
type direction_flag = | Upto| Downto
type private_flag = | Private| Public
type mutable_flag = | Immutable| Mutable
type virtual_flag = | Virtual| Concrete
type override_flag = | Override| Fresh
type closed_flag = | Closed| Open
type arg_label = | Nolabel| Labelled of string| Optional of string
type variance = | Covariant| Contravariant| Invariant