hphp/hack/src/typing/typing_reified_check.ml

   1 (*
   2  * Copyright (c) 2018, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the MIT license found in the
   6  * LICENSE file in the "hack" directory of this source tree.
   7  *
   8  *)
   9
  10 open Hh_prelude
  11 open Typing_defs
  12 open Type_validator
  13 module Env = Tast_env
  14 module SN = Naming_special_names
  15 module UA = SN.UserAttributes
  16 module Cls = Decl_provider.Class
  17 module Nast = Aast
  18
  19 let validator =
  20   object (this)
  21     inherit type_validator as super
  22
  23     method! on_tapply acc r (p, h) tyl =
  24       if String.equal h SN.Classes.cTypename then
  25         this#invalid acc r "a typename"
  26       else if String.equal h SN.Classes.cClassname then
  27         this#invalid acc r "a classname"
  28       else if
  29         String.equal h SN.Typehints.wildcard
  30         && not (Env.get_allow_wildcards acc.env)
  31       then
  32         this#invalid acc r "a wildcard"
  33       else
  34         super#on_tapply acc r (p, h) tyl
  35
  36     method! on_tgeneric acc r t _tyargs =
  37       (* Ignoring type aguments: If there were any, then this generic variable isn't allowed to be
  38         reified anyway *)
  39       (* TODO(T70069116) actually implement that check *)
  40       match Env.get_reified acc.env t with
  41       | Nast.Erased -> this#invalid acc r "not reified"
  42       | Nast.SoftReified -> this#invalid acc r "soft reified"
  43       | Nast.Reified -> acc
  44
  45     method! on_tvarray acc r _ = this#invalid acc r "an array type"
  46
  47     method! on_tdarray acc r _ _ = this#invalid acc r "an array type"
  48
  49     method! on_tvarray_or_darray acc r _ _ = this#invalid acc r "an array type"
  50
  51     method! on_tfun acc r _ = this#invalid acc r "a function type"
  52
  53     method! on_typeconst acc is_concrete typeconst =
  54       match typeconst.ttc_abstract with
  55       | _ when Option.is_some typeconst.ttc_reifiable || is_concrete ->
  56         super#on_typeconst acc is_concrete typeconst
  57       | _ ->
  58         let r = Reason.Rwitness (fst typeconst.ttc_name) in
  59         let kind =
  60           "an abstract type constant without the __Reifiable attribute"
  61         in
  62         this#invalid acc r kind
  63
  64     method! on_taccess acc r (root, ids) =
  65       let acc =
  66         match acc.reification with
  67         | Unresolved -> this#on_type acc root
  68         | Resolved -> acc
  69       in
  70       super#on_taccess acc r (root, ids)
  71
  72     method! on_tthis acc r =
  73       this#invalid acc r "the late static bound this type"
  74   end