hphp/hack/src/typing/nast_check/interface_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 Aast
  12
  13 let enforce_no_body m =
  14   match m.m_body.fb_ast with
  15   | [] -> ()
  16   | _ -> Errors.abstract_body (fst m.m_name)
  17
  18 let check_interface c =
  19   List.iter c.c_uses (fun (p, _) -> Errors.interface_use_trait p);
  20
  21   let (statics, vars) = split_vars c in
  22   begin
  23     match vars with
  24     | hd :: _ ->
  25       let pos = fst hd.cv_id in
  26       Errors.interface_with_member_variable pos
  27     | _ -> ()
  28   end;
  29
  30   begin
  31     match statics with
  32     | hd :: _ ->
  33       let pos = fst hd.cv_id in
  34       Errors.interface_with_static_member_variable pos
  35     | _ -> ()
  36   end;
  37
  38   (* make sure interfaces do not contain partially abstract type constants *)
  39   List.iter c.c_typeconsts (fun tc ->
  40       if
  41         Option.is_some tc.c_tconst_constraint && Option.is_some tc.c_tconst_type
  42       then
  43         Errors.interface_with_partial_typeconst (fst tc.c_tconst_name));
  44
  45   (* make sure that interfaces only have empty public methods *)
  46   List.iter ~f:enforce_no_body c.c_methods
  47
  48 let handler =
  49   object
  50     inherit Nast_visitor.handler_base
  51
  52     method! at_class_ _ c =
  53       if Ast_defs.(equal_class_kind c.c_kind Cinterface) then check_interface c
  54   end