hphp/hack/src/typing/tast_check/tautology_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 [@@@warning "-33"]
  11
  12 open Hh_prelude
  13
  14 [@@@warning "+33"]
  15
  16 open Ast_defs
  17 open Aast
  18 open Tast
  19
  20 let handler =
  21   object
  22     inherit Tast_visitor.handler_base
  23
  24     method! at_expr env =
  25       function
  26       | (_, p, Binop { bop = (Eqeqeq | Diff2) as bop; lhs; rhs }) ->
  27         Tast_env.assert_nontrivial p bop env (get_type lhs) (get_type rhs)
  28       | _ -> ()
  29   end