hphp/hack/src/typing/typing_structure.ml

   1 (**
   2  * Copyright (c) 2015, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the BSD-style license found in the
   6  * LICENSE file in the "hack" directory of this source tree. An additional grant
   7  * of patent rights can be found in the PATENTS file in the same directory.
   8  *
   9  *)
  10
  11 (* This module implements the typing for type_structure. *)
  12 open Core
  13 open Nast
  14 open Typing_defs
  15
  16 module Env = Typing_env
  17 module Reason = Typing_reason
  18 module SN = Naming_special_names
  19 module TUtils = Typing_utils
  20
  21 (* For TypeStructure<T> (which is an alias for a shape) where the type
  22 parameter T is a class/enum/interface or an alias that resolves to a
  23 class, we can guarantee the existence of the 'classname' field, hence
  24 this function transforms the 'classname' field of the TypeStructure<T>
  25 from ?classname<T> to classname<T>. *)
  26 let transform_classname_ty ty =
  27   match ty with
  28   | r, Tshape (fk, fdm) ->
  29     let p = Reason.to_pos r in
  30     let kClassname = Nast.SFlit (p, "classname") in
  31     let f_clsname = ShapeMap.get kClassname fdm in
  32     (match f_clsname with
  33      | Some (_, Toption (_, Tabstract (AKnewtype (c, tyl), _) as fty))
  34          when c = SN.Classes.cClassname ->
  35        (match List.hd tyl with
  36         | Some tty ->
  37           (match TUtils.get_base_type tty with
  38            | (_, Tclass _)
  39            | (_, Tabstract (AKenum _, _)) ->
  40              let fdm = ShapeMap.add kClassname fty fdm in
  41              (r, Tshape (fk, fdm))
  42            | _ -> ty)
  43         | _ -> ty)
  44      | _ -> ty (* should not reach *))
  45   | _ -> ty (* should not reach *)