libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14
  10
  11 // <variant>
  12
  13 // template <size_t I, class... Types>
  14 //  constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
  15 //   get_if(variant<Types...>* v) noexcept;
  16 // template <size_t I, class... Types>
  17 //  constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
  18 //   get_if(const variant<Types...>* v) noexcept;
  19
  20 #include "test_macros.h"
  21 #include "variant_test_helpers.h"
  22 #include <cassert>
  23 #include <memory>
  24 #include <variant>
  25
  26 void test_const_get_if() {
  27   {
  28     using V = std::variant<int>;
  29     constexpr const V *v = nullptr;
  30     static_assert(std::get_if<0>(v) == nullptr, "");
  31   }
  32   {
  33     using V = std::variant<int, const long>;
  34     constexpr V v(42);
  35     ASSERT_NOEXCEPT(std::get_if<0>(&v));
  36     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), const int *);
  37     static_assert(*std::get_if<0>(&v) == 42, "");
  38     static_assert(std::get_if<1>(&v) == nullptr, "");
  39   }
  40   {
  41     using V = std::variant<int, const long>;
  42     constexpr V v(42l);
  43     ASSERT_SAME_TYPE(decltype(std::get_if<1>(&v)), const long *);
  44     static_assert(*std::get_if<1>(&v) == 42, "");
  45     static_assert(std::get_if<0>(&v) == nullptr, "");
  46   }
  47 // FIXME: Remove these once reference support is reinstated
  48 #if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
  49   {
  50     using V = std::variant<int &>;
  51     int x = 42;
  52     const V v(x);
  53     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), int *);
  54     assert(std::get_if<0>(&v) == &x);
  55   }
  56   {
  57     using V = std::variant<int &&>;
  58     int x = 42;
  59     const V v(std::move(x));
  60     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), int *);
  61     assert(std::get_if<0>(&v) == &x);
  62   }
  63   {
  64     using V = std::variant<const int &&>;
  65     int x = 42;
  66     const V v(std::move(x));
  67     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), const int *);
  68     assert(std::get_if<0>(&v) == &x);
  69   }
  70 #endif
  71 }
  72
  73 void test_get_if() {
  74   {
  75     using V = std::variant<int>;
  76     V *v = nullptr;
  77     assert(std::get_if<0>(v) == nullptr);
  78   }
  79   {
  80     using V = std::variant<int, long>;
  81     V v(42);
  82     ASSERT_NOEXCEPT(std::get_if<0>(&v));
  83     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), int *);
  84     assert(*std::get_if<0>(&v) == 42);
  85     assert(std::get_if<1>(&v) == nullptr);
  86   }
  87   {
  88     using V = std::variant<int, const long>;
  89     V v(42l);
  90     ASSERT_SAME_TYPE(decltype(std::get_if<1>(&v)), const long *);
  91     assert(*std::get_if<1>(&v) == 42);
  92     assert(std::get_if<0>(&v) == nullptr);
  93   }
  94 // FIXME: Remove these once reference support is reinstated
  95 #if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
  96   {
  97     using V = std::variant<int &>;
  98     int x = 42;
  99     V v(x);
 100     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), int *);
 101     assert(std::get_if<0>(&v) == &x);
 102   }
 103   {
 104     using V = std::variant<const int &>;
 105     int x = 42;
 106     V v(x);
 107     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), const int *);
 108     assert(std::get_if<0>(&v) == &x);
 109   }
 110   {
 111     using V = std::variant<int &&>;
 112     int x = 42;
 113     V v(std::move(x));
 114     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), int *);
 115     assert(std::get_if<0>(&v) == &x);
 116   }
 117   {
 118     using V = std::variant<const int &&>;
 119     int x = 42;
 120     V v(std::move(x));
 121     ASSERT_SAME_TYPE(decltype(std::get_if<0>(&v)), const int *);
 122     assert(std::get_if<0>(&v) == &x);
 123   }
 124 #endif
 125 }
 126
 127 int main(int, char**) {
 128   test_const_get_if();
 129   test_get_if();
 130
 131   return 0;
 132 }