hphp/hack/src/typing/tast_check/dynamic_method_call_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 Tast
  11 open Typing_defs
  12
  13 module Env = Tast_env
  14
  15 let handler = object
  16   inherit Tast_visitor.handler_base
  17
  18   method! at_Call env _ expr _ _ _ =
  19     match snd expr with
  20     (* If rhs's expression is some Id, then we've got a normal function call
  21      * $x->foo
  22      * That's totally fine, ignore it. *)
  23     | Obj_get (_, (_, Id _), _) -> ()
  24     (* Otherwise, rhs is some dynamic invocation expression like: $x->$f *)
  25     (* if lhs is already dynamic, we let the dynamic invoke happen for now *)
  26     | Obj_get (((_, (_, Tdynamic)), _), _, _) -> ()
  27     (* if it's not dynamic, then we're in our error case. Grab the offending
  28      * expression's position and report it *)
  29     | Obj_get (_, ((rhs_pos, _), _), _)
  30       when Env.is_strict env ->
  31         Errors.dynamic_method_call rhs_pos
  32     | _ -> ()
  33   end