Update issue status for LWG 2744

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284322 91177308-0d34-0410-b5e6-96231b3b80d8

include/any

@@ -200,7 +200,7 @@ public:
     , class _Tp = decay_t<_ValueType>
     , class = enable_if_t<
         !is_same<_Tp, any>::value &&
-        !__is_inplace_type<_ValueType>::value &&
+        !__is_inplace_type_tag<_ValueType>::value &&
         is_copy_constructible<_Tp>::value>
     >
   _LIBCPP_INLINE_VISIBILITY
@@ -241,15 +241,12 @@ public:
     return *this;
   }
 
-  // TODO: Should this be constrained to disallow in_place types like the
-  // ValueType constructor?
   template <
       class _ValueType
     , class _Tp = decay_t<_ValueType>
     , class = enable_if_t<
           !is_same<_Tp, any>::value
-          && is_copy_constructible<_Tp>::value
-          && !__is_inplace_type<_ValueType>::value>
+          && is_copy_constructible<_Tp>::value>
     >
   _LIBCPP_INLINE_VISIBILITY
   any & operator=(_ValueType && __rhs);

include/utility

@@ -928,10 +928,20 @@ inline in_place_tag in_place(__in_place_index_tag<_Nx>) {
     return in_place_tag(__in_place_tag{});
 }
 
-template <class _Tp>   struct __is_inplace_type : false_type {};
-template <>            struct __is_inplace_type<in_place_t> : true_type {};
-template <class _Tp>   struct __is_inplace_type<in_place_type_t<_Tp>> : true_type {};
-template <size_t _Idx> struct __is_inplace_type<in_place_index_t<_Idx>> : true_type {};
+template <class _Tp>   struct __is_inplace_tag_imp : false_type {};
+template <>            struct __is_inplace_tag_imp<in_place_tag(__in_place_tag)> : true_type {};
+template <class _Tp>   struct __is_inplace_tag_imp<in_place_tag(__in_place_type_tag<_Tp>)> : true_type {};
+template <size_t _Idx> struct __is_inplace_tag_imp<in_place_tag(__in_place_index_tag<_Idx>)> : true_type {};
+
+template <class _Tp>
+using __is_inplace_tag = __is_inplace_tag_imp<remove_pointer_t<decay_t<_Tp>>>;
+
+template <class _Tp> struct __is_inplace_type_tag_imp : false_type {};
+template <class _Tp> struct __is_inplace_type_tag_imp<in_place_tag(__in_place_type_tag<_Tp>)> : true_type {};
+
+template <class _Tp>
+using __is_inplace_type_tag = __is_inplace_type_tag_imp<remove_pointer_t<decay_t<_Tp>>>;
+
 
 #endif // _LIBCPP_STD_VER > 14
 

test/libcxx/utilities/utility/utility.inplace/__is_inplace_tag.pass.cpp

@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <utility>
+
+// template <class Tp>
+// struct __is_inplace_tag;
+
+#include <utility>
+#include <cassert>
+
+template <bool Expect, class RefFn, class Fn = std::remove_reference_t<RefFn>>
+void do_test() {
+    static_assert(std::__is_inplace_tag<RefFn>::value == Expect, "");
+    static_assert(std::__is_inplace_tag<Fn>::value == Expect, "");
+    static_assert(std::__is_inplace_tag<std::decay_t<RefFn>>::value == Expect, "");
+    static_assert(std::__is_inplace_tag<Fn*>::value == Expect, "");
+}
+
+int main() {
+    do_test<true, std::in_place_t>();
+    do_test<true, std::in_place_type_t<int>>();
+    do_test<true, std::in_place_index_t<42>>();
+    do_test<false, std::in_place_tag>();
+    do_test<false, void>();
+    do_test<false, void*>();
+    do_test<false, std::in_place_tag(&)(...)>();
+}

test/libcxx/utilities/utility/utility.inplace/__is_inplace_type.pass.cpp

@@ -1,27 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++98, c++03, c++11, c++14
-
-// <utility>
-
-// template <class Tp>
-// struct __is_inplace_type;
-
-#include <utility>
-#include <cassert>
-
-int main() {
-    static_assert(std::__is_inplace_type<std::in_place_t>::value, "");
-    static_assert(std::__is_inplace_type<std::in_place_type_t<int>>::value, "");
-    static_assert(std::__is_inplace_type<std::in_place_index_t<static_cast<size_t>(-1)>>::value, "");
-    static_assert(!std::__is_inplace_type<std::in_place_tag>::value, "");
-    static_assert(!std::__is_inplace_type<void*>::value, "");
-    static_assert(!std::__is_inplace_type<std::in_place_tag(&)(...)>::value, "");
-}

test/std/utilities/any/any.class/any.assign/copy.pass.cpp

@@ -153,7 +153,7 @@ void test_copy_assign_throws()
 
         assert(Tp::count == 1);
         assertEmpty<Tp>(lhs);
-        assertContains<Tp>(rhs);
+        assertContains<Tp>(rhs, 1);
     }
     {
         any lhs((small(2)));
@@ -166,7 +166,7 @@ void test_copy_assign_throws()
         assert(small::count == 1);
         assert(Tp::count == 1);
         assertContains<small>(lhs, 2);
-        assertContains<Tp>(rhs);
+        assertContains<Tp>(rhs, 1);
     }
     {
         any lhs((large(2)));
@@ -179,7 +179,7 @@ void test_copy_assign_throws()
         assert(large::count == 1);
         assert(Tp::count == 1);
         assertContains<large>(lhs, 2);
-        assertContains<Tp>(rhs);
+        assertContains<Tp>(rhs, 1);
     }
 #endif
 }

test/std/utilities/any/any.class/any.assign/value.pass.cpp

@@ -172,15 +172,15 @@ void test_assign_throws() {
 // * std::in_place type.
 // * Non-copyable types
 void test_sfinae_constraints() {
-    {
+    { // Only the constructors are required to SFINAE on in_place_t
         using Tag = std::in_place_type_t<int>;
         using RawTag = std::remove_reference_t<Tag>;
-        static_assert(!std::is_assignable<std::any, RawTag&&>::value, "");
+        static_assert(std::is_assignable<std::any, RawTag&&>::value, "");
     }
     {
         struct Dummy { Dummy() = delete; };
         using T = std::in_place_type_t<Dummy>;
-        static_assert(!std::is_assignable<std::any, T>::value, "");
+        static_assert(std::is_assignable<std::any, T>::value, "");
     }
     {
         // Test that the ValueType&& constructor SFINAE's away when the

test/std/utilities/any/any.class/any.cons/value.pass.cpp

@@ -108,17 +108,12 @@ void test_copy_move_value() {
 
 // Test that any(ValueType&&) is *never* selected for a std::in_place type.
 void test_sfinae_constraints() {
-    using Tag = std::in_place_type_t<int>;
-#if defined(__clang__)
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wignored-qualifiers"
-#endif
-    static_assert(std::is_same<Tag, const Tag>::value, "");
-#if defined(__clang__)
-#pragma clang diagnostic pop
-#endif
+    using BadTag = std::in_place_type_t<int>;
+    using OKTag = std::in_place_t;
+    using OKDecay = std::decay_t<OKTag>;
     // Test that the tag type is properly handled in SFINAE
-    Tag t = std::in_place;
+    BadTag t = std::in_place;
+    OKTag ot = std::in_place;
     {
         std::any a(t);
         assertContains<int>(a, 0);
@@ -127,11 +122,24 @@ void test_sfinae_constraints() {
         std::any a(std::move(t));
         assertContains<int>(a, 0);
     }
+    {
+        std::any a(ot);
+        assertContains<OKDecay>(a, ot);
+    }
+    {
+        OKDecay d = ot;
+        std::any a(d);
+        assertContains<OKDecay>(a, ot);
+    }
     {
         struct Dummy { Dummy() = delete; };
         using T = std::in_place_type_t<Dummy>;
         static_assert(!std::is_constructible<std::any, T>::value, "");
     }
+    {
+        using DecayTag = std::decay_t<BadTag>;
+        static_assert(!std::is_constructible<std::any, DecayTag>::value, "");
+    }
     {
         // Test that the ValueType&& constructor SFINAE's away when the
         // argument is non-copyable

test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp

@@ -53,7 +53,7 @@ int main()
     {
         any a(large(1));
         assert(large::count == 1);
-        assertContains<large>(a);
+        assertContains<large>(a, 1);
 
         a.reset();
 

test/support/any_helpers.h

@@ -59,21 +59,30 @@ void assertEmpty(std::any const& a) {
     assert(any_cast<LastType const>(&a) == nullptr);
 }
 
+template <class Type>
+constexpr auto has_value_member(int) -> decltype(std::declval<Type&>().value, true)
+{ return true; }
+template <class> constexpr bool has_value_member(long) { return false; }
+
+
 // Assert that an 'any' object stores the specified 'Type' and 'value'.
 template <class Type>
-void assertContains(std::any const& a, int value = 1) {
+std::enable_if_t<has_value_member<Type>(0)>
+assertContains(std::any const& a, int value) {
     assert(a.has_value());
     assert(containsType<Type>(a));
     assert(std::any_cast<Type const &>(a).value == value);
 }
 
-template <>
-void assertContains<int>(std::any const& a, int value) {
+template <class Type, class Value>
+std::enable_if_t<!has_value_member<Type>(0)>
+assertContains(std::any const& a, Value value) {
     assert(a.has_value());
-    assert(containsType<int>(a));
-    assert(std::any_cast<int const &>(a) == value);
+    assert(containsType<Type>(a));
+    assert(std::any_cast<Type const &>(a) == value);
 }
 
+
 // Modify the value of a "test type" stored within an any to the specified
 // 'value'.
 template <class Type>

www/upcoming_meeting.html

@@ -111,7 +111,7 @@
 	 <tr><td><a href="http://wg21.link/LWG2739">2739</a></td><td>Issue with time_point non-member subtraction with an unsigned duration</td><td>Issaquah</td><td>Patch Ready</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2740">2740</a></td><td>constexpr optional<T>::operator-></td><td>Issaquah</td><td></td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2742">2742</a></td><td>Inconsistent string interface taking string_view</td><td>Issaquah</td><td>Patch Ready</td></tr>
-	 <tr><td><a href="http://wg21.link/LWG2744">2744</a></td><td>any's in_place constructors</td><td>Issaquah</td><td></td></tr>
+	 <tr><td><a href="http://wg21.link/LWG2744">2744</a></td><td>any's in_place constructors</td><td>Issaquah</td><td>Implemented in trunk</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2745">2745</a></td><td>[fund.ts.v2] Implementability of LWG 2451</td><td>Issaquah</td><td></td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2747">2747</a></td><td>Possibly redundant std::move in [alg.foreach]</td><td>Issaquah</td><td>Patch ready</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2748">2748</a></td><td>swappable traits for optionals</td><td>Issaquah</td><td></td></tr>
@@ -189,7 +189,7 @@
 <li>2739 - Patch and tests ready</li>
 <li>2740 - <i>std::optional</i></li>
 <li>2742 - Patch and tests ready</li>
-<li>2744 - <i>std::any</i></li>
+<li>2744 - <i>std::any</i>: We already do this. We also check for a decayed in_place_type_t. </li>
 <li>2745 - <i>std::optional</i> for LFTS -- should be considered for C++17</li>
 <li>2747 - Patch ready, but I can't think of any way to test it.</li>
 <li>2748 - <i>std::optional</i></li>