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      1 // -*- C++ -*-
      2 //===----------------------------------------------------------------------===//
      3 //
      4 //                     The LLVM Compiler Infrastructure
      5 //
      6 // This file is dual licensed under the MIT and the University of Illinois Open
      7 // Source Licenses. See LICENSE.TXT for details.
      8 //
      9 //===----------------------------------------------------------------------===//
     10 #ifndef SUPPORT_VARIANT_TEST_HELPERS_HPP
     11 #define SUPPORT_VARIANT_TEST_HELPERS_HPP
     12 
     13 #include <type_traits>
     14 #include <utility>
     15 #include <cassert>
     16 
     17 #include "test_macros.h"
     18 
     19 #if TEST_STD_VER <= 14
     20 #error This file requires C++17
     21 #endif
     22 
     23 // FIXME: Currently the variant<T&> tests are disabled using this macro.
     24 #define TEST_VARIANT_HAS_NO_REFERENCES
     25 
     26 #ifndef TEST_HAS_NO_EXCEPTIONS
     27 struct CopyThrows {
     28   CopyThrows() = default;
     29   CopyThrows(CopyThrows const&) { throw 42; }
     30   CopyThrows& operator=(CopyThrows const&) { throw 42; }
     31 };
     32 
     33 struct MoveThrows {
     34   static int alive;
     35   MoveThrows() { ++alive; }
     36   MoveThrows(MoveThrows const&) {++alive;}
     37   MoveThrows(MoveThrows&&) {  throw 42; }
     38   MoveThrows& operator=(MoveThrows const&) { return *this; }
     39   MoveThrows& operator=(MoveThrows&&) { throw 42; }
     40   ~MoveThrows() { --alive; }
     41 };
     42 
     43 int MoveThrows::alive = 0;
     44 
     45 struct MakeEmptyT {
     46   static int alive;
     47   MakeEmptyT() { ++alive; }
     48   MakeEmptyT(MakeEmptyT const&) {
     49       ++alive;
     50       // Don't throw from the copy constructor since variant's assignment
     51       // operator performs a copy before committing to the assignment.
     52   }
     53   MakeEmptyT(MakeEmptyT &&) {
     54       throw 42;
     55   }
     56   MakeEmptyT& operator=(MakeEmptyT const&) {
     57       throw 42;
     58   }
     59   MakeEmptyT& operator=(MakeEmptyT&&) {
     60       throw 42;
     61   }
     62    ~MakeEmptyT() { --alive; }
     63 };
     64 static_assert(std::is_swappable_v<MakeEmptyT>, ""); // required for test
     65 
     66 int MakeEmptyT::alive = 0;
     67 
     68 template <class Variant>
     69 void makeEmpty(Variant& v) {
     70     Variant v2(std::in_place_type<MakeEmptyT>);
     71     try {
     72         v = std::move(v2);
     73         assert(false);
     74     } catch (...) {
     75         assert(v.valueless_by_exception());
     76     }
     77 }
     78 #endif // TEST_HAS_NO_EXCEPTIONS
     79 
     80 
     81 #endif // SUPPORT_VARIANT_TEST_HELPERS_HPP
     82