# Module Ast_406.Asttypes

    module Asttypes: sig .. end

Auxiliary AST types used by parsetree and typedtree.

    type constant =

`|` | `Const_int of `int``
`|` | `Const_char of `char``
`|` | `Const_string of `string * 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 label = string

    type arg_label =

`|` | `Nolabel`
`|` | `Labelled of `string``
`|` | `Optional of `string``

    type 'a loc = 'a Location.loc = {

`` | `txt : `'a`;`
`` | `loc : `Location.t`;`

}

    type variance =

`|` | `Covariant`
`|` | `Contravariant`
`|` | `Invariant`