Implement LWG 2842 - optional(U&&) needs to SFINAE on decay_t<in_place_t>

llvm-svn: 299100

diff --git a/libcxx/include/optional b/libcxx/include/optional
index 002842f..a80120f 100644 (file)
--- a/libcxx/include/optional
+++ b/libcxx/include/optional
@@ -531,7 +531,7 @@ private:
     };
     template <class _Up>
     using _CheckOptionalArgsCtor = conditional_t<
-        !is_same_v<in_place_t, _Up> &&
+        !is_same_v<decay_t<_Up>, in_place_t> &&
         !is_same_v<decay_t<_Up>, optional>,
         _CheckOptionalArgsConstructor,
         __check_tuple_constructor_fail

diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
index 4020d70..d068fbc 100644 (file)
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
@@ -35,6 +35,11 @@ struct ExplicitThrow
     constexpr explicit ExplicitThrow(int x) { if (x != -1) TEST_THROW(6);}
 };
 
+struct ImplicitAny {
+  template <class U>
+  constexpr ImplicitAny(U&&) {}
+};
+
 
 template <class To, class From>
 constexpr bool implicit_conversion(optional<To>&& opt, const From& v)
@@ -79,6 +84,15 @@ void test_implicit()
         using T = TestTypes::TestType;
         assert(implicit_conversion<T>(3, T(3)));
     }
+  {
+    using O = optional<ImplicitAny>;
+    static_assert(!test_convertible<O, std::in_place_t>(), "");
+    static_assert(!test_convertible<O, std::in_place_t&>(), "");
+    static_assert(!test_convertible<O, const std::in_place_t&>(), "");
+    static_assert(!test_convertible<O, std::in_place_t&&>(), "");
+    static_assert(!test_convertible<O, const std::in_place_t&&>(), "");
+
+  }
 #ifndef TEST_HAS_NO_EXCEPTIONS
     {
         try {

diff --git a/libcxx/www/cxx1z_status.html b/libcxx/www/cxx1z_status.html
index 6b832d6..bca7f32 100644 (file)
--- a/libcxx/www/cxx1z_status.html
+++ b/libcxx/www/cxx1z_status.html
@@ -460,7 +460,7 @@
        <tr><td><a href="http://wg21.link/LWG2835">2835</a></td><td>LWG 2536 seems to misspecify &lt;tgmath.h&gt;</td><td>Kona</td><td></td></tr>
        <tr><td><a href="http://wg21.link/LWG2837">2837</a></td><td>gcd and lcm should support a wider range of input values</td><td>Kona</td><td>Complete</td></tr>
        <tr><td><a href="http://wg21.link/LWG2838">2838</a></td><td>is_literal_type specification needs a little cleanup</td><td>Kona</td><td>Complete</td></tr>
-       <tr><td><a href="http://wg21.link/LWG2842">2842</a></td><td>in_place_t check for optional::optional(U&amp;&amp;) should decay U</td><td>Kona</td><td></td></tr>
+       <tr><td><a href="http://wg21.link/LWG2842">2842</a></td><td>in_place_t check for optional::optional(U&amp;&amp;) should decay U</td><td>Kona</td><td>Complete</td></tr>
        <tr><td><a href="http://wg21.link/LWG2850">2850</a></td><td>std::function move constructor does unnecessary work</td><td>Kona</td><td></td></tr>
        <tr><td><a href="http://wg21.link/LWG2853">2853</a></td><td>Possible inconsistency in specification of erase in [vector.modifiers]</td><td>Kona</td><td></td></tr>
        <tr><td><a href="http://wg21.link/LWG2855">2855</a></td><td>std::throw_with_nested("string_literal")</td><td>Kona</td><td></td></tr>