Index: include/iterator
===================================================================
--- include/iterator
+++ include/iterator
@@ -533,6 +533,22 @@
          __has_iterator_category_convertible_to<_Tp, input_iterator_tag>::value && 
         !__has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value> {};
 
+#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
+template<class _InputIterator>
+using __iter_value_type = typename iterator_traits<_InputIterator>::value_type;
+
+template<class _InputIterator>
+using __iter_key_type = remove_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>;
+
+template<class _InputIterator>
+using __iter_mapped_type = typename iterator_traits<_InputIterator>::value_type::second_type;
+
+template<class _InputIterator>
+using __iter_to_alloc_type = pair<
+    add_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>,
+    typename iterator_traits<_InputIterator>::value_type::second_type>;
+#endif
+
 template<class _Category, class _Tp, class _Distance = ptrdiff_t,
          class _Pointer = _Tp*, class _Reference = _Tp&>
 struct _LIBCPP_TEMPLATE_VIS iterator
Index: include/map
===================================================================
--- include/map
+++ include/map
@@ -1461,6 +1461,32 @@
 #endif
 };
 
+#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
+template<class _InputIterator, class _Compare = less<__iter_key_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
+         class = typename enable_if<!__is_allocator<_Compare>::value, void>::type,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+map(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
+  -> map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Compare, _Allocator>;
+
+template<class _Key, class _Tp, class _Compare = less<_Key>,
+         class _Allocator = allocator<pair<const _Key, _Tp>>,
+         class = typename enable_if<!__is_allocator<_Compare>::value, void>::type,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+map(initializer_list<pair<_Key, _Tp>>, _Compare = _Compare(), _Allocator = _Allocator())
+  -> map<_Key, _Tp, _Compare, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+map(_InputIterator, _InputIterator, _Allocator)
+  -> map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+         less<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+map(initializer_list<pair<_Key, _Tp>>, _Allocator)
+  -> map<_Key, _Tp, less<_Key>, _Allocator>;
+#endif
 
 #ifndef _LIBCPP_CXX03_LANG
 template <class _Key, class _Tp, class _Compare, class _Allocator>
@@ -2082,6 +2108,33 @@
     typedef unique_ptr<__node, _Dp> __node_holder;
 };
 
+#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
+template<class _InputIterator, class _Compare = less<__iter_key_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
+         class = typename enable_if<!__is_allocator<_Compare>::value, void>::type,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+multimap(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
+  -> multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Compare, _Allocator>;
+
+template<class _Key, class _Tp, class _Compare = less<_Key>,
+         class _Allocator = allocator<pair<const _Key, _Tp>>,
+         class = typename enable_if<!__is_allocator<_Compare>::value, void>::type,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+multimap(initializer_list<pair<_Key, _Tp>>, _Compare = _Compare(), _Allocator = _Allocator())
+  -> multimap<_Key, _Tp, _Compare, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+multimap(_InputIterator, _InputIterator, _Allocator)
+  -> multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+         less<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = typename enable_if<__is_allocator<_Allocator>::value, void>::type>
+multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
+  -> multimap<_Key, _Tp, less<_Key>, _Allocator>;
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 template <class _Key, class _Tp, class _Compare, class _Allocator>
 multimap<_Key, _Tp, _Compare, _Allocator>::multimap(multimap&& __m, const allocator_type& __a)
Index: test/std/containers/associative/map/map.cons/deduct.fail.cpp
===================================================================
--- /dev/null
+++ test/std/containers/associative/map/map.cons/deduct.fail.cpp
@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <map>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+// template<class InputIterator,
+// class Compare = less<iter-key-type<InputIterator>>,
+// class Allocator = allocator<iter-to-alloc-type<InputIterator>>>
+//       map(InputIterator, InputIterator,
+//                Compare = Compare(), Allocator = Allocator())
+// -> map<iter-key-type<InputIterator>, iter-mapped-type<InputIterator>, Compare, Allocator>;
+//     template<class Key, class T, class Compare = less<Key>,
+//              class Allocator = allocator<pair<const Key, T>>>
+//       map(initializer_list<pair<Key, T>>, Compare = Compare(), Allocator = Allocator())
+//         -> map<Key, T, Compare, Allocator>;
+//     template<class InputIterator, class Allocator>
+//       map(InputIterator, InputIterator, Allocator)
+// -> map<iter-key-type<InputIterator>, iter-mapped-type<InputIterator>,
+//        less<iter-key-type<InputIterator>>, Allocator>;
+//     template<class Key, class T, class Allocator>
+//       map(initializer_list<pair<Key, T>>, Allocator) -> map<Key, T, less<Key>, Allocator>;
+
+#include <climits> // INT_MAX
+#include <map>
+#include <type_traits>
+
+struct A {};
+
+int main(int, char**)
+{
+    {
+        A a;
+        std::map s(a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        std::allocator<int> a;
+        std::map s(a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        A a;
+        std::map s(a, a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        A a;
+        std::map s{a}; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        A a;
+        std::map s{a, a}; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        std::map m{ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        std::map m({ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} }, std::greater<int>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        using P = std::pair<const int, int>;
+        std::map m({ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} }, std::greater<int>(), std::allocator<P>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        using P = std::pair<const int, int>;
+        std::map m({ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} }, std::allocator<P>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+
+  return 0;
+}
Index: test/std/containers/associative/map/map.cons/deduct.pass.cpp
===================================================================
--- /dev/null
+++ test/std/containers/associative/map/map.cons/deduct.pass.cpp
@@ -0,0 +1,133 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <map>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+// template<class InputIterator,
+// class Compare = less<iter-value-type<InputIterator>>,
+// class Allocator = allocator<iter-value-type<InputIterator>>>
+//       map(InputIterator, InputIterator,
+//                Compare = Compare(), Allocator = Allocator())
+// -> map<iter-value-type<InputIterator>, Compare, Allocator>;
+//     template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
+//       map(initializer_list<Key>, Compare = Compare(), Allocator = Allocator())
+//         -> map<Key, Compare, Allocator>;
+//     template<class InputIterator, class Allocator>
+//       map(InputIterator, InputIterator, Allocator)
+// -> map<iter-value-type<InputIterator>, less<iter-value-type<InputIterator>>, Allocator>;
+//     template<class Key, class Allocator>
+//       map(initializer_list<Key>, Allocator) -> map<Key, less<Key>, Allocator>;
+
+#include <map>
+#include <cassert>
+#include <climits> // INT_MAX
+
+#include "test_allocator.h"
+
+struct A {
+    friend bool operator<(A, A) { return false; }
+};
+
+int main(int, char**)
+{
+
+//  Test the explicit deduction guides
+    {
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::map m(std::begin(arr), std::end(arr));
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::map m(std::begin(arr), std::end(arr), std::greater<int>());
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int, std::greater<int>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::map m(std::begin(arr), std::end(arr), std::greater<int>(), test_allocator<P>(0, 42));
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int, std::greater<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 42);
+    }
+
+    {
+    std::map m{ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} };
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::map m({ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} }, std::greater<int>());
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int, std::greater<int>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    std::map m({ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} }, std::greater<int>(), test_allocator<P>(0, 43));
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int, std::greater<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 43);
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::map m(std::begin(arr), std::end(arr), test_allocator<P>(0, 44));
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int, std::less<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 44);
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    std::map m({ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} }, test_allocator<P>(0, 45));
+
+    static_assert(std::is_same_v<decltype(m), std::map<int, int, std::less<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 45);
+    }
+
+    {
+    std::map<long, int> source;
+    std::map m(source); // map(map &)
+    static_assert(std::is_same_v<decltype(m), std::map<long, int>>, "");
+    assert(m.size() == 0);
+    }
+
+    {
+    std::map<long, int> source;
+    std::map m{source}; // map(map &)
+    static_assert(std::is_same_v<decltype(m), std::map<long, int>>, "");
+    assert(m.size() == 0);
+    }
+
+  return 0;
+}
Index: test/std/containers/associative/multimap/multimap.cons/deduct.fail.cpp
===================================================================
--- /dev/null
+++ test/std/containers/associative/multimap/multimap.cons/deduct.fail.cpp
@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <map>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+// template<class InputIterator,
+// class Compare = less<iter-key-type<InputIterator>>,
+// class Allocator = allocator<iter-to-alloc-type<InputIterator>>>
+//       multimap(InputIterator, InputIterator,
+//                Compare = Compare(), Allocator = Allocator())
+// -> multimap<iter-key-type<InputIterator>, iter-multimapped-type<InputIterator>, Compare, Allocator>;
+//     template<class Key, class T, class Compare = less<Key>,
+//              class Allocator = allocator<pair<const Key, T>>>
+//       multimap(initializer_list<pair<Key, T>>, Compare = Compare(), Allocator = Allocator())
+//         -> multimap<Key, T, Compare, Allocator>;
+//     template<class InputIterator, class Allocator>
+//       multimap(InputIterator, InputIterator, Allocator)
+// -> multimap<iter-key-type<InputIterator>, iter-multimapped-type<InputIterator>,
+//        less<iter-key-type<InputIterator>>, Allocator>;
+//     template<class Key, class T, class Allocator>
+//       multimap(initializer_list<pair<Key, T>>, Allocator) -> multimap<Key, T, less<Key>, Allocator>;
+
+#include <climits> // INT_MAX
+#include <map>
+#include <type_traits>
+
+struct A {};
+
+int main(int, char**)
+{
+    {
+        A a;
+        std::multimap s(a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        std::allocator<int> a;
+        std::multimap s(a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        A a;
+        std::multimap s(a, a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        A a;
+        std::multimap s{a}; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        A a;
+        std::multimap s{a, a}; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        std::multimap m{ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        std::multimap m({ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} }, std::greater<int>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        using P = std::pair<const int, int>;
+        std::multimap m({ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} }, std::greater<int>(), std::allocator<P>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        using P = std::pair<const int, int>;
+        std::multimap m({ {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} }, std::allocator<P>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+
+  return 0;
+}
Index: test/std/containers/associative/multimap/multimap.cons/deduct.pass.cpp
===================================================================
--- /dev/null
+++ test/std/containers/associative/multimap/multimap.cons/deduct.pass.cpp
@@ -0,0 +1,133 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <map>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+// template<class InputIterator,
+// class Compare = less<iter-value-type<InputIterator>>,
+// class Allocator = allocator<iter-value-type<InputIterator>>>
+//       multimap(InputIterator, InputIterator,
+//                Compare = Compare(), Allocator = Allocator())
+// -> multimap<iter-value-type<InputIterator>, Compare, Allocator>;
+//     template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
+//       multimap(initializer_list<Key>, Compare = Compare(), Allocator = Allocator())
+//         -> multimap<Key, Compare, Allocator>;
+//     template<class InputIterator, class Allocator>
+//       multimap(InputIterator, InputIterator, Allocator)
+// -> multimap<iter-value-type<InputIterator>, less<iter-value-type<InputIterator>>, Allocator>;
+//     template<class Key, class Allocator>
+//       multimap(initializer_list<Key>, Allocator) -> multimap<Key, less<Key>, Allocator>;
+
+#include <map>
+#include <cassert>
+#include <climits> // INT_MAX
+
+#include "test_allocator.h"
+
+struct A {
+    friend bool operator<(A, A) { return false; }
+};
+
+int main(int, char**)
+{
+
+//  Test the explicit deduction guides
+    {
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::multimap m(std::begin(arr), std::end(arr));
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::multimap m(std::begin(arr), std::end(arr), std::greater<int>());
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int, std::greater<int>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::multimap m(std::begin(arr), std::end(arr), std::greater<int>(), test_allocator<P>(0, 42));
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int, std::greater<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 42);
+    }
+
+    {
+    std::multimap m{ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} };
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::multimap m({ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} }, std::greater<int>());
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int, std::greater<int>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    std::multimap m({ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} }, std::greater<int>(), test_allocator<P>(0, 43));
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int, std::greater<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {INT_MAX,1}, {3,1}, {2,2}, {1,1}, {1,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 43);
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    const std::pair<int, int> arr[] = { {1,1}, {2,2}, {1,1}, {INT_MAX,1}, {3,1} };
+    std::multimap m(std::begin(arr), std::end(arr), test_allocator<P>(0, 44));
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int, std::less<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 44);
+    }
+
+    {
+    using P = std::pair<const int, int>;
+    std::multimap m({ std::pair{1,1}, std::pair{2,2}, std::pair{1,1}, std::pair{INT_MAX,1}, std::pair{3,1} }, test_allocator<P>(0, 45));
+
+    static_assert(std::is_same_v<decltype(m), std::multimap<int, int, std::less<int>, test_allocator<P>>>, "");
+    std::pair<const int, int> expected_m[] = { {1,1}, {1,1}, {2,2}, {3,1}, {INT_MAX,1} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 45);
+    }
+
+    {
+    std::multimap<long, int> source;
+    std::multimap m(source); // multimap(multimap &)
+    static_assert(std::is_same_v<decltype(m), std::multimap<long, int>>, "");
+    assert(m.size() == 0);
+    }
+
+    {
+    std::multimap<long, int> source;
+    std::multimap m{source}; // multimap(multimap &)
+    static_assert(std::is_same_v<decltype(m), std::multimap<long, int>>, "");
+    assert(m.size() == 0);
+    }
+
+  return 0;
+}