hphp/hack/src/typing/tast_check/xhp_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 Core_kernel
  11 open Tast
  12 open Typing_defs
  13
  14 module Env = Tast_env
  15
  16 let check_xhp_children env pos ty =
  17   let _, ty = Env.expand_type env ty in
  18   let _, ty = Env.fold_unresolved env ty in
  19   let tys = match ty with
  20     | _, Tunresolved ts -> ts
  21     | _ -> [ty] in
  22   if not @@ List.for_all ~f:(Env.is_xhp_child env pos) tys
  23   then
  24     let ty_str = Env.print_error_ty env ty in
  25     let msgl = Reason.to_string ("This is "^ty_str) (fst ty) in
  26     Errors.illegal_xhp_child pos msgl
  27
  28 let handler = object
  29   inherit Tast_visitor.handler_base
  30
  31   method! at_expr env = function
  32     | _, Xml (_, _, tel) ->
  33       List.iter tel ~f:(fun ((pos, ty), _) -> check_xhp_children env pos ty)
  34     | _ -> ()
  35 end