Add contains method to map types

[zoecarver]

Summary

Implements P0458R2, adding contains to map, multimap, unordered_map, unordered_multimap, set, multiset, unordered_set, and (finally) unordered_multiset.

My editor messed up the spacing when I originally made this patch so let me know if you find any weird white space.

This patch is the predecessor to P0920R2 which I can submit once this one has been reviewed.

[zoecarver]

include/map

194 ↗

(On Diff #190561)

Seems like this should be the correct spacing but I can revert it if you want.

include/set

364 ↗

(On Diff #190561)

count isnt in the summary but it is declared in the class.

[mclow.lists]

We don't usually gang tests for multiple containers together - one/container is more common,

include/map

198 ↗

(On Diff #190561)

Add a comment to the synopsis indicating that this is a C++20 feature: // C++20

[EricWF]

test/std/containers/contains.pass.cpp

1 ↗

(On Diff #190561)

I really really REALLY like the way you wrote this test!

If a constraint is shared across all containers, or is specified in the container requirements table, then we should test it like this.

[ldionne]

include/unordered_map

1268 ↗

(On Diff #190561)

You forgot to add to the synopsis.

test/std/containers/contains.pass.cpp

1 ↗

(On Diff #190561)

Yes, I share that feeling.

[zoecarver]

test/std/containers/contains.pass.cpp

1 ↗

(On Diff #190561)

Awesome! Happy you like it.

@mclow.lists

We don't usually gang tests for multiple containers together - one/container is more common,

Do you want me to break this into multiple tests?

[zoecarver]

Fixed:

• main args
• synopsis comment
• // C++20
• remove __hash (from other patch)

[ldionne]

Please also mark the feature as implemented in www/cxx2a_status.html.

include/set

164 ↗

(On Diff #190692)

Please mark all the contains functions added in C++20 as // C++20.

[zoecarver]

Fix:

• add // C++20 to all synopsis comments
• update test with license and header comments
• update www/status

[ldionne]

This is almost good to go except for a nitpick!

test/std/containers/contains.pass.cpp

8 ↗

(On Diff #190852)

We normally put the license first thing in the file.

[zoecarver]

test/std/containers/contains.pass.cpp

8 ↗

(On Diff #190852)

So license, then #includes, then other comments, then code?

[zoecarver]

Fix license comment.

[jloser]

include/map

1408 ↗

(On Diff #190853)

I think we should only provide the declaration and definition of contains when _LIBCPP_STD_VER > 17. Otherwise, someone compiling with trunk and -std=c++14 would be able to use contains, and this is only meant for C++20 or later.

[ldionne]

include/map

1408 ↗

(On Diff #190853)

Hmm yes, this was the intent but somehow I missed that during the review. Please only enable in C++20 and above.

[zoecarver]

include/map

1408 ↗

(On Diff #190853)

Will do.

[zoecarver]

Only enable contains after C++17.

[jloser]

include/map

2051 ↗

(On Diff #193829)

Just a note that while contains supports transparent keys now, find does not yet. Are you planning on implementing http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0919r3.html or want me to do it?

[zoecarver]

include/map

2051 ↗

(On Diff #193829)

I already implemented it in D59886. I didn't want to have to wait on one of the patches so I went a bit out of scope by adding transparent keys to this patch.

[zoecarver]

• rebase off master

Is the mono-test OK? If so, I will commit.

[zoecarver]

• remove templated contains methods (we will implement those in D59886)

[zoecarver]

• split tests up into four files

As soon as this is approved, I will commit. It would be great to get this committed before Wednesday.

[ldionne]

My approval still stands, it looked good last time I looked at it and nothing has changed since then. I think you can commit this.

[zoecarver]

Committed as rL366170.

libcxx/include/map

// map operations:
           iterator find(const key_type& k);
     const_iterator find(const key_type& k) const;
     template<typename K>
         iterator find(const K& x);              // C++14
     template<typename K>
         const_iterator find(const K& x) const;  // C++14
     template<typename K>
       size_type count(const K& x) const;        // C++14
-
     size_type      count(const key_type& k) const;
+        bool contains(const key_type& x) const; // C++20
           iterator lower_bound(const key_type& k);
     const_iterator lower_bound(const key_type& k) const;
     template<typename K>
         iterator lower_bound(const K& x);              // C++14
     template<typename K>
         const_iterator lower_bound(const K& x) const;  // C++14
 
           iterator upper_bound(const key_type& k);
// map operations:
           iterator find(const key_type& k);
     const_iterator find(const key_type& k) const;
     template<typename K>
         iterator find(const K& x);              // C++14
     template<typename K>
         const_iterator find(const K& x) const;  // C++14
     template<typename K>
       size_type count(const K& x) const;        // C++14
-
     size_type      count(const key_type& k) const;
+        bool contains(const key_type& x) const; // C++20
           iterator lower_bound(const key_type& k);
     const_iterator lower_bound(const key_type& k) const;
     template<typename K>
         iterator lower_bound(const K& x);              // C++14
     template<typename K>
         const_iterator lower_bound(const K& x) const;  // C++14
 
           iterator upper_bound(const key_type& k);
#endif
     size_type      count(const key_type& __k) const
         {return __tree_.__count_unique(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
     _LIBCPP_INLINE_VISIBILITY
     typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
     count(const _K2& __k) const {return __tree_.__count_multi(__k);}
 #endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
     _LIBCPP_INLINE_VISIBILITY
     iterator lower_bound(const key_type& __k)
         {return __tree_.lower_bound(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator lower_bound(const key_type& __k) const
         {return __tree_.lower_bound(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
#endif
     size_type      count(const key_type& __k) const
         {return __tree_.__count_multi(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
     _LIBCPP_INLINE_VISIBILITY
     typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
     count(const _K2& __k) const {return __tree_.__count_multi(__k);}
 #endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
     _LIBCPP_INLINE_VISIBILITY
     iterator lower_bound(const key_type& __k)
         {return __tree_.lower_bound(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator lower_bound(const key_type& __k) const
             {return __tree_.lower_bound(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>

libcxx/include/set

public:
     // set operations:
           iterator find(const key_type& k);
     const_iterator find(const key_type& k) const;
     template<typename K>
         iterator find(const K& x);
     template<typename K>
         const_iterator find(const K& x) const;  // C++14
     template<typename K>
         size_type count(const K& x) const;        // C++14
-
     size_type      count(const key_type& k) const;
+        bool contains(const key_type& x) const; // C++20
           iterator lower_bound(const key_type& k);
     const_iterator lower_bound(const key_type& k) const;
     template<typename K>
         iterator lower_bound(const K& x);              // C++14
     template<typename K>
         const_iterator lower_bound(const K& x) const;  // C++14
 
           iterator upper_bound(const key_type& k);
public:
 
     // set operations:
           iterator find(const key_type& k);
     const_iterator find(const key_type& k) const;
     template<typename K>
         iterator find(const K& x);
     template<typename K>
         const_iterator find(const K& x) const;  // C++14
-
+    template<typename K>
+        size_type count(const K& x) const;      // C++14
     size_type      count(const key_type& k) const;
+        bool contains(const key_type& x) const; // C++20
           iterator lower_bound(const key_type& k);
     const_iterator lower_bound(const key_type& k) const;
     template<typename K>
         iterator lower_bound(const K& x);              // C++14
     template<typename K>
         const_iterator lower_bound(const K& x) const;  // C++14
 
           iterator upper_bound(const key_type& k);
#endif
     size_type      count(const key_type& __k) const
         {return __tree_.__count_unique(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
     _LIBCPP_INLINE_VISIBILITY
     typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
     count(const _K2& __k) const                    {return __tree_.__count_multi(__k);}
 #endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
     _LIBCPP_INLINE_VISIBILITY
     iterator lower_bound(const key_type& __k)
         {return __tree_.lower_bound(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator lower_bound(const key_type& __k) const
         {return __tree_.lower_bound(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
size_type      count(const key_type& __k) const
         {return __tree_.__count_multi(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>
     _LIBCPP_INLINE_VISIBILITY
     typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
     count(const _K2& __k) const            {return __tree_.__count_multi(__k);}
 #endif
 
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
     _LIBCPP_INLINE_VISIBILITY
     iterator lower_bound(const key_type& __k)
         {return __tree_.lower_bound(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator lower_bound(const key_type& __k) const
             {return __tree_.lower_bound(__k);}
 #if _LIBCPP_STD_VER > 11
     template <typename _K2>

libcxx/include/unordered_map

void swap(unordered_map&)
             __is_nothrow_swappable<key_equal>::value);
 
     hasher hash_function() const;
     key_equal key_eq() const;
 
     iterator       find(const key_type& k);
     const_iterator find(const key_type& k) const;
     size_type count(const key_type& k) const;
+    bool contains(const key_type& k) const; // C++20
     pair<iterator, iterator>             equal_range(const key_type& k);
     pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
 
     mapped_type& operator[](const key_type& k);
     mapped_type& operator[](key_type&& k);
 
     mapped_type&       at(const key_type& k);
     const mapped_type& at(const key_type& k) const;
void swap(unordered_multimap&)
             __is_nothrow_swappable<key_equal>::value);
 
     hasher hash_function() const;
     key_equal key_eq() const;
 
     iterator       find(const key_type& k);
     const_iterator find(const key_type& k) const;
     size_type count(const key_type& k) const;
+    bool contains(const key_type& k) const; // C++20
     pair<iterator, iterator>             equal_range(const key_type& k);
     pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
 
     size_type bucket_count() const noexcept;
     size_type max_bucket_count() const noexcept;
 
     size_type bucket_size(size_type n) const;
     size_type bucket(const key_type& k) const;
key_equal key_eq() const
         {return __table_.key_eq().key_eq();}
 
     _LIBCPP_INLINE_VISIBILITY
     iterator       find(const key_type& __k)       {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator find(const key_type& __k) const {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     size_type count(const key_type& __k) const {return __table_.__count_unique(__k);}
+    #if _LIBCPP_STD_VER > 17
+        _LIBCPP_INLINE_VISIBILITY
+        bool contains(const key_type& __k) const {return find(__k) != end();}
+    #endif // _LIBCPP_STD_VER > 17
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, iterator>             equal_range(const key_type& __k)
         {return __table_.__equal_range_unique(__k);}
     _LIBCPP_INLINE_VISIBILITY
     pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
         {return __table_.__equal_range_unique(__k);}
 
     mapped_type& operator[](const key_type& __k);
key_equal key_eq() const
         {return __table_.key_eq().key_eq();}
 
     _LIBCPP_INLINE_VISIBILITY
     iterator       find(const key_type& __k)       {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator find(const key_type& __k) const {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     size_type count(const key_type& __k) const {return __table_.__count_multi(__k);}
+    #if _LIBCPP_STD_VER > 17
+        _LIBCPP_INLINE_VISIBILITY
+        bool contains(const key_type& __k) const {return find(__k) != end();}
+    #endif // _LIBCPP_STD_VER > 17
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, iterator>             equal_range(const key_type& __k)
         {return __table_.__equal_range_multi(__k);}
     _LIBCPP_INLINE_VISIBILITY
     pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
         {return __table_.__equal_range_multi(__k);}
 
     _LIBCPP_INLINE_VISIBILITY

libcxx/include/unordered_set

void swap(unordered_set&)
                  noexcept(swap(declval<key_equal&>(), declval<key_equal&>()))); // C++17
 
     hasher hash_function() const;
     key_equal key_eq() const;
 
     iterator       find(const key_type& k);
     const_iterator find(const key_type& k) const;
     size_type count(const key_type& k) const;
+    bool contains(const key_type& k) const; // C++20
     pair<iterator, iterator>             equal_range(const key_type& k);
     pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
 
     size_type bucket_count() const noexcept;
     size_type max_bucket_count() const noexcept;
 
     size_type bucket_size(size_type n) const;
     size_type bucket(const key_type& k) const;
void swap(unordered_multiset&)
                  noexcept(swap(declval<key_equal&>(), declval<key_equal&>()))); // C++17
 
     hasher hash_function() const;
     key_equal key_eq() const;
 
     iterator       find(const key_type& k);
     const_iterator find(const key_type& k) const;
     size_type count(const key_type& k) const;
+    bool contains(const key_type& k) const; // C++20
     pair<iterator, iterator>             equal_range(const key_type& k);
     pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
 
     size_type bucket_count() const noexcept;
     size_type max_bucket_count() const noexcept;
 
     size_type bucket_size(size_type n) const;
     size_type bucket(const key_type& k) const;
#endif
     key_equal key_eq() const {return __table_.key_eq();}
 
     _LIBCPP_INLINE_VISIBILITY
     iterator       find(const key_type& __k)       {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator find(const key_type& __k) const {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     size_type count(const key_type& __k) const {return __table_.__count_unique(__k);}
+    #if _LIBCPP_STD_VER > 17
+        _LIBCPP_INLINE_VISIBILITY
+        bool contains(const key_type& __k) const {return find(__k) != end();}
+    #endif // _LIBCPP_STD_VER > 17
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, iterator>             equal_range(const key_type& __k)
         {return __table_.__equal_range_unique(__k);}
     _LIBCPP_INLINE_VISIBILITY
     pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
         {return __table_.__equal_range_unique(__k);}
 
     _LIBCPP_INLINE_VISIBILITY
#endif
     key_equal key_eq() const {return __table_.key_eq();}
 
     _LIBCPP_INLINE_VISIBILITY
     iterator       find(const key_type& __k)       {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator find(const key_type& __k) const {return __table_.find(__k);}
     _LIBCPP_INLINE_VISIBILITY
     size_type count(const key_type& __k) const {return __table_.__count_multi(__k);}
+    #if _LIBCPP_STD_VER > 17
+        _LIBCPP_INLINE_VISIBILITY
+        bool contains(const key_type& __k) const {return find(__k) != end();}
+    #endif // _LIBCPP_STD_VER > 17
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, iterator>             equal_range(const key_type& __k)
         {return __table_.__equal_range_multi(__k);}
     _LIBCPP_INLINE_VISIBILITY
     pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
         {return __table_.__equal_range_multi(__k);}
 
     _LIBCPP_INLINE_VISIBILITY

libcxx/test/std/containers/associative/map/contains.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <cassert>
+#include <map>
+
+// <map>
+
+// bool contains(const key_type& x) const;
+
+template <typename T, typename P, typename B, typename... Pairs>
+void test(B bad, Pairs... args) {
+    T map;
+    P pairs[] = {args...};
+
+    for (auto& p : pairs) map.insert(p);
+    for (auto& p : pairs) assert(map.contains(p.first));
+
+    assert(!map.contains(bad));
+}
+
+struct E { int a = 1; double b = 1; char c = 1; };
+
+int main(int, char**)
+{
+    {
+        test<std::map<char, int>, std::pair<char, int> >(
+            'e', std::make_pair('a', 10), std::make_pair('b', 11),
+            std::make_pair('c', 12), std::make_pair('d', 13));
+
+        test<std::map<char, char>, std::pair<char, char> >(
+            'e', std::make_pair('a', 'a'), std::make_pair('b', 'a'),
+            std::make_pair('c', 'a'), std::make_pair('d', 'b'));
+
+        test<std::map<int, E>, std::pair<int, E> >(
+            -1, std::make_pair(1, E{}), std::make_pair(2, E{}),
+            std::make_pair(3, E{}), std::make_pair(4, E{}));
+    }
+    {
+        test<std::multimap<char, int>, std::pair<char, int> >(
+            'e', std::make_pair('a', 10), std::make_pair('b', 11),
+            std::make_pair('c', 12), std::make_pair('d', 13));
+
+        test<std::multimap<char, char>, std::pair<char, char> >(
+            'e', std::make_pair('a', 'a'), std::make_pair('b', 'a'),
+            std::make_pair('c', 'a'), std::make_pair('d', 'b'));
+
+        test<std::multimap<int, E>, std::pair<int, E> >(
+            -1, std::make_pair(1, E{}), std::make_pair(2, E{}),
+            std::make_pair(3, E{}), std::make_pair(4, E{}));
+    }
+
+    return 0;
+}
+

libcxx/test/std/containers/associative/set/contains.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <cassert>
+#include <set>
+
+// <set>
+
+// bool contains(const key_type& x) const;
+
+template <typename T, typename V, typename B, typename... Vals>
+void test(B bad, Vals... args) {
+    T set;
+    V vals[] = {args...};
+
+    for (auto& v : vals) set.insert(v);
+    for (auto& v : vals) assert(set.contains(v));
+
+    assert(!set.contains(bad));
+}
+
+struct E { int a = 1; double b = 1; char c = 1; };
+
+int main(int, char**)
+{
+    {
+        test<std::set<int>, int>(14, 10, 11, 12, 13);
+        test<std::set<char>, char>('e', 'a', 'b', 'c', 'd');
+    }
+    {
+        test<std::multiset<int>, int>(14, 10, 11, 12, 13);
+        test<std::multiset<char>, char>('e', 'a', 'b', 'c', 'd');
+    }
+
+    return 0;
+}
+

libcxx/test/std/containers/unord/unord.map/contains.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <cassert>
+#include <unordered_map>
+
+// <unordered_map>
+
+// bool contains(const key_type& x) const;
+
+template <typename T, typename P, typename B, typename... Pairs>
+void test(B bad, Pairs... args) {
+    T map;
+    P pairs[] = {args...};
+
+    for (auto& p : pairs) map.insert(p);
+    for (auto& p : pairs) assert(map.contains(p.first));
+
+    assert(!map.contains(bad));
+}
+
+struct E { int a = 1; double b = 1; char c = 1; };
+
+int main(int, char**)
+{
+    {
+        test<std::unordered_map<char, int>, std::pair<char, int> >(
+            'e', std::make_pair('a', 10), std::make_pair('b', 11),
+            std::make_pair('c', 12), std::make_pair('d', 13));
+
+        test<std::unordered_map<char, char>, std::pair<char, char> >(
+            'e', std::make_pair('a', 'a'), std::make_pair('b', 'a'),
+            std::make_pair('c', 'a'), std::make_pair('d', 'b'));
+
+        test<std::unordered_map<int, E>, std::pair<int, E> >(
+            -1, std::make_pair(1, E{}), std::make_pair(2, E{}),
+            std::make_pair(3, E{}), std::make_pair(4, E{}));
+    }
+    {
+        test<std::unordered_multimap<char, int>, std::pair<char, int> >(
+            'e', std::make_pair('a', 10), std::make_pair('b', 11),
+            std::make_pair('c', 12), std::make_pair('d', 13));
+
+        test<std::unordered_multimap<char, char>, std::pair<char, char> >(
+            'e', std::make_pair('a', 'a'), std::make_pair('b', 'a'),
+            std::make_pair('c', 'a'), std::make_pair('d', 'b'));
+
+        test<std::unordered_multimap<int, E>, std::pair<int, E> >(
+            -1, std::make_pair(1, E{}), std::make_pair(2, E{}),
+            std::make_pair(3, E{}), std::make_pair(4, E{}));
+    }
+
+    return 0;
+}
+

libcxx/test/std/containers/unord/unord.set/contains.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <cassert>
+#include <unordered_set>
+
+// <unordered_set>
+
+// bool contains(const key_type& x) const;
+
+template <typename T, typename V, typename B, typename... Vals>
+void test(B bad, Vals... args) {
+    T set;
+    V vals[] = {args...};
+
+    for (auto& v : vals) set.insert(v);
+    for (auto& v : vals) assert(set.contains(v));
+
+    assert(!set.contains(bad));
+}
+
+struct E { int a = 1; double b = 1; char c = 1; };
+
+int main(int, char**)
+{
+    {
+        test<std::unordered_set<int>, int>(14, 10, 11, 12, 13);
+        test<std::unordered_set<char>, char>('e', 'a', 'b', 'c', 'd');
+    }
+    {
+        test<std::unordered_multiset<int>, int>(14, 10, 11, 12, 13);
+        test<std::unordered_multiset<char>, char>('e', 'a', 'b', 'c', 'd');
+    }
+
+    return 0;
+}
+

libcxx/www/cxx2a_status.html

-->
   <tr><td><a href="https://wg21.link/P0754R2">P0754R2</a></td><td>LWG</td><td>&lt;version&gt;</td><td>Jacksonville</td><td>Complete</td><td>7.0</td></tr>
   <tr><td><a href="https://wg21.link/P0809R0">P0809R0</a></td><td>LWG</td><td>Comparing Unordered Containers</td><td>Jacksonville</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0858R0">P0858R0</a></td><td>LWG</td><td>Constexpr iterator requirements</td><td>Jacksonville</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0905R1">P0905R1</a></td><td>CWG</td><td>Symmetry for spaceship</td><td>Jacksonville</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0966R1">P0966R1</a></td><td>LWG</td><td><tt>string::reserve</tt> Should Not Shrink</td><td>Jacksonville</td><td>Complete</td><td>8.0</td></tr>
 
     <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0019R8">P0019R8</a></td><td>LWG</td><td>Atomic Ref</td><td>Rapperswil</td><td></td><td></td></tr>
-  <tr><td><a href="https://wg21.link/P0458R2">P0458R2</a></td><td>LWG</td><td>Checking for Existence of an Element in Associative Containers</td><td>Rapperswil</td><td></td><td></td></tr>
+  <tr><td><a href="https://wg21.link/P0458R2">P0458R2</a></td><td>LWG</td><td>Checking for Existence of an Element in Associative Containers</td><td>Rapperswil</td><td>Complete</td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0475R1">P0475R1</a></td><td>LWG</td><td>LWG 2511: guaranteed copy elision for piecewise construction</td><td>Rapperswil</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0476R2">P0476R2</a></td><td>LWG</td><td>Bit-casting object representations</td><td>Rapperswil</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0528R3">P0528R3</a></td><td>CWG</td><td>The Curious Case of Padding Bits, Featuring Atomic Compare-and-Exchange</td><td>Rapperswil</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0542R5">P0542R5</a></td><td>CWG</td><td>Support for contract based programming in C++</td><td>Rapperswil</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0556R3">P0556R3</a></td><td>LWG</td><td>Integral power-of-2 operations</td><td>Rapperswil</td><td>Complete</td><td>9.0</td></tr>
   <tr><td><a href="https://wg21.link/P0619R4">P0619R4</a></td><td>LWG</td><td>Reviewing Deprecated Facilities of C++17 for C++20</td><td>Rapperswil</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0646R1">P0646R1</a></td><td>LWG</td><td>Improving the Return Value of Erase-Like Algorithms</td><td>Rapperswil</td><td></td><td></td></tr>
   <tr><td><a href="https://wg21.link/P0722R3">P0722R3</a></td><td>CWG</td><td>Efficient sized delete for variable sized classes</td><td>Rapperswil</td><td>Complete</td><td>9.0</td></tr>