hphp/hack/src/typing/typing_func_terminality.ml

   1 (*
   2  * Copyright (c) 2015, 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 open Typing_defs
  13 module Env = Typing_env
  14 module Cls = Folded_class
  15
  16 (* Not adding a Typing_dep here because it will be added when the
  17  * Nast is fully processed (by the caller of this code) *)
  18 let get_fun ctx name =
  19   match Decl_provider.get_fun ctx name |> Decl_entry.to_option with
  20   | Some { fe_type; _ } -> begin
  21     match get_node fe_type with
  22     | Tfun ft -> Some ft
  23     | _ -> None
  24   end
  25   | _ -> None
  26
  27 let get_static_meth
  28     (ctx : Provider_context.t) (cls_name : string) (meth_name : string) =
  29   match Decl_provider.get_class ctx cls_name with
  30   | Decl_entry.DoesNotExist
  31   | Decl_entry.NotYetAvailable ->
  32     None
  33   | Decl_entry.Found cls -> begin
  34     match Cls.get_smethod cls meth_name with
  35     | None -> None
  36     | Some { Typing_defs.ce_type = (lazy ty); _ } -> begin
  37       match get_node ty with
  38       | Tfun fty -> Some fty
  39       | _ -> None
  40     end
  41   end
  42
  43 let funopt_is_noreturn = function
  44   | Some { ft_ret; _ } -> is_prim Tnoreturn ft_ret
  45   | _ -> false
  46
  47 let static_meth_is_noreturn env ci meth_id =
  48   let class_name =
  49     match ci with
  50     | CI cls_id -> Some (snd cls_id)
  51     | CIself
  52     | CIstatic ->
  53       Env.get_self_id env
  54     | CIparent -> Env.get_parent_id env
  55     | CIexpr _ -> None
  56     (* we declared the types, but didn't check the bodies yet
  57                        so can't tell anything here *)
  58   in
  59   match class_name with
  60   | Some class_name ->
  61     funopt_is_noreturn
  62       (get_static_meth (Env.get_ctx env) class_name (snd meth_id))
  63   | None -> false
  64
  65 let typed_expression_exits (ty, _, _e) = is_type_no_return (get_node ty)
  66
  67 let expression_exits env (_, _, e) =
  68   match e with
  69   | Call { func = (_, _, Id (_, fun_name)); _ } ->
  70     funopt_is_noreturn @@ get_fun (Env.get_ctx env) fun_name
  71   | Call { func = (_, _, Class_const ((_, _, ci), meth_id)); _ } ->
  72     static_meth_is_noreturn env ci meth_id
  73   | _ -> false
  74
  75 let is_noreturn env =
  76   let (_env, ret_ty) =
  77     Env.expand_type env (Env.get_return env).Typing_env_return_info.return_type
  78   in
  79   is_prim Tnoreturn ret_ty