[libc++] Take 2: Implement CTAD for map and multimap

This is a re-application of r362986 (which was reverted in r363688) with fixes
for the issue that caused it to be reverted.

Thanks to Arthur O'Dwyer for the patch.

Differential Revision: https://reviews.llvm.org/D58587

llvm-svn: 363968

6 files changed, 702 insertions, 0 deletions

diff --git a/libcxx/test/std/containers/associative/map/map.cons/deduct.fail.cpp b/libcxx/test/std/containers/associative/map/map.cons/deduct.fail.cpp
new file mode 100644
index 00000000000..2e719da6442
--- /dev/null
+++ b/libcxx/test/std/containers/associative/map/map.cons/deduct.fail.cpp
@@ -0,0 +1,107 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// XFAIL: clang-6, apple-clang-9.0, apple-clang-9.1, apple-clang-10.0
+//  clang-6 gives different error messages.
+
+// 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 <climits> // INT_MAX
+#include <functional>
+#include <map>
+#include <type_traits>
+
+struct NotAnAllocator {
+    friend bool operator<(NotAnAllocator, NotAnAllocator) { return false; }
+};
+
+using P = std::pair<int, long>;
+using PC = std::pair<const int, long>;
+
+int main(int, char**)
+{
+    {
+        // cannot deduce Key and T from nothing
+        std::map m; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce Key and T from just (Compare)
+        std::map m(std::less<int>{});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce Key and T from just (Compare, Allocator)
+        std::map m(std::less<int>{}, std::allocator<PC>{});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce Key and T from just (Allocator)
+        std::map m(std::allocator<PC>{});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // refuse to rebind the allocator if Allocator::value_type is not exactly what we expect
+        const P arr[] = { {1,1L}, {2,2L}, {3,3L} };
+        std::map m(arr, arr + 3, std::allocator<P>());
+            // expected-error-re@map:* {{static_assert failed{{( due to requirement '.*')?}} "Allocator::value_type must be same type as value_type"}}
+    }
+    {
+        // cannot convert from some arbitrary unrelated type
+        NotAnAllocator a;
+        std::map m(a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::map m{ {1,1L}, {2,2L}, {3,3L} };
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::map m({ {1,1L}, {2,2L}, {3,3L} }, std::less<int>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::map m({ {1,1L}, {2,2L}, {3,3L} }, std::less<int>(), std::allocator<PC>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::map m({ {1,1L}, {2,2L}, {3,3L} }, std::allocator<PC>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // since we have parens, not braces, this deliberately does not find the initializer_list constructor
+        std::map m(P{1,1L});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+    {
+        // since we have parens, not braces, this deliberately does not find the initializer_list constructor
+        std::map m(PC{1,1L});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'map'}}
+    }
+
+    return 0;
+}
diff --git a/libcxx/test/std/containers/associative/map/map.cons/deduct.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/deduct.pass.cpp
new file mode 100644
index 00000000000..9075d27106d
--- /dev/null
+++ b/libcxx/test/std/containers/associative/map/map.cons/deduct.pass.cpp
@@ -0,0 +1,137 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <algorithm> // std::equal
+#include <cassert>
+#include <climits> // INT_MAX
+#include <functional>
+#include <map>
+#include <type_traits>
+
+#include "test_allocator.h"
+
+using P = std::pair<int, long>;
+using PC = std::pair<const int, long>;
+
+int main(int, char**)
+{
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long>);
+    const PC expected_m[] = { {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr), std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::greater<int>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr), std::greater<int>(), test_allocator<PC>(0, 42));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::greater<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 42);
+    }
+
+    {
+    std::map<int, long> source;
+    std::map m(source);
+    ASSERT_SAME_TYPE(decltype(m), decltype(source));
+    assert(m.size() == 0);
+    }
+
+    {
+    std::map<int, long> source;
+    std::map m{source};  // braces instead of parens
+    ASSERT_SAME_TYPE(decltype(m), decltype(source));
+    assert(m.size() == 0);
+    }
+
+    {
+    std::map<int, long> source;
+    std::map m(source, std::map<int, long>::allocator_type());
+    ASSERT_SAME_TYPE(decltype(m), decltype(source));
+    assert(m.size() == 0);
+    }
+
+    {
+    std::map m{ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} };
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long>);
+    const PC expected_m[] = { {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::map m({ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} }, std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::greater<int>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::map m({ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} }, std::greater<int>(), test_allocator<PC>(0, 43));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::greater<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 43);
+    }
+
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr), test_allocator<PC>(0, 44));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::less<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 44);
+    }
+
+    {
+    std::map m({ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} }, test_allocator<PC>(0, 45));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::less<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 45);
+    }
+
+    return 0;
+}
diff --git a/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp
new file mode 100644
index 00000000000..77785363403
--- /dev/null
+++ b/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp
@@ -0,0 +1,107 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <algorithm> // std::equal
+#include <cassert>
+#include <climits> // INT_MAX
+#include <functional>
+#include <map>
+#include <type_traits>
+
+#include "test_allocator.h"
+
+using P = std::pair<int, long>;
+using PC = std::pair<const int, long>;
+using PCC = std::pair<const int, const long>;
+
+int main(int, char**)
+{
+    {
+    const PCC arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, const long>);
+    const PCC expected_m[] = { {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const PCC arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr), std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, const long, std::greater<int>>);
+    const PCC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1, 1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const PCC arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::map m(std::begin(arr), std::end(arr), std::greater<int>(), test_allocator<PCC>(0, 42));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, const long, std::greater<int>, test_allocator<PCC>>);
+    const PCC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1, 1L} };
+    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{ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} };
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long>);
+    const PC expected_m[] = { {1, 1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::map m({ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} }, std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::greater<int>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1, 1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::map m({ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} }, std::greater<int>(), test_allocator<PC>(0, 43));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::greater<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1, 1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 43);
+    }
+
+    {
+    std::map m({ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} }, test_allocator<PC>(0, 45));
+
+    ASSERT_SAME_TYPE(decltype(m), std::map<int, long, std::less<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {1, 1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 45);
+    }
+
+    return 0;
+}
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct.fail.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct.fail.cpp
new file mode 100644
index 00000000000..70fa2522cc1
--- /dev/null
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct.fail.cpp
@@ -0,0 +1,107 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// XFAIL: clang-6, apple-clang-9.0, apple-clang-9.1, apple-clang-10.0
+//  clang-6 gives different error messages.
+
+// 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 <climits> // INT_MAX
+#include <functional>
+#include <map>
+#include <type_traits>
+
+struct NotAnAllocator {
+    friend bool operator<(NotAnAllocator, NotAnAllocator) { return false; }
+};
+
+using P = std::pair<int, long>;
+using PC = std::pair<const int, long>;
+
+int main(int, char**)
+{
+    {
+        // cannot deduce Key and T from nothing
+        std::multimap m; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce Key and T from just (Compare)
+        std::multimap m(std::less<int>{});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce Key and T from just (Compare, Allocator)
+        std::multimap m(std::less<int>{}, std::allocator<PC>{});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce Key and T from just (Allocator)
+        std::multimap m(std::allocator<PC>{});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // refuse to rebind the allocator if Allocator::value_type is not exactly what we expect
+        const P arr[] = { {1,1L}, {2,2L}, {3,3L} };
+        std::multimap m(arr, arr + 3, std::allocator<P>());
+            // expected-error-re@map:* {{static_assert failed{{( due to requirement '.*')?}} "Allocator::value_type must be same type as value_type"}}
+    }
+    {
+        // cannot convert from some arbitrary unrelated type
+        NotAnAllocator a;
+        std::multimap m(a); // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::multimap m{ {1,1L}, {2,2L}, {3,3L} };
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::multimap m({ {1,1L}, {2,2L}, {3,3L} }, std::less<int>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::multimap m({ {1,1L}, {2,2L}, {3,3L} }, std::less<int>(), std::allocator<PC>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // cannot deduce that the inner braced things should be std::pair and not something else
+        std::multimap m({ {1,1L}, {2,2L}, {3,3L} }, std::allocator<PC>());
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // since we have parens, not braces, this deliberately does not find the initializer_list constructor
+        std::multimap m(P{1,1L});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+    {
+        // since we have parens, not braces, this deliberately does not find the initializer_list constructor
+        std::multimap m(PC{1,1L});
+            // expected-error@-1{{no viable constructor or deduction guide for deduction of template arguments of 'multimap'}}
+    }
+
+    return 0;
+}
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct.pass.cpp
new file mode 100644
index 00000000000..0a28d7835ea
--- /dev/null
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct.pass.cpp
@@ -0,0 +1,137 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <algorithm> // std::equal
+#include <cassert>
+#include <climits> // INT_MAX
+#include <functional>
+#include <map>
+#include <type_traits>
+
+#include "test_allocator.h"
+
+using P = std::pair<int, long>;
+using PC = std::pair<const int, long>;
+
+int main(int, char**)
+{
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long>);
+    const PC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr), std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::greater<int>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr), std::greater<int>(), test_allocator<PC>(0, 42));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::greater<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 42);
+    }
+
+    {
+    std::multimap<int, long> source;
+    std::multimap m(source);
+    ASSERT_SAME_TYPE(decltype(m), decltype(source));
+    assert(m.size() == 0);
+    }
+
+    {
+    std::multimap<int, long> source;
+    std::multimap m{source};  // braces instead of parens
+    ASSERT_SAME_TYPE(decltype(m), decltype(source));
+    assert(m.size() == 0);
+    }
+
+    {
+    std::multimap<int, long> source;
+    std::multimap m(source, std::map<int, long>::allocator_type());
+    ASSERT_SAME_TYPE(decltype(m), decltype(source));
+    assert(m.size() == 0);
+    }
+
+    {
+    std::multimap m{ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} };
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long>);
+    const PC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::multimap m({ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} }, std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::greater<int>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::multimap m({ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} }, std::greater<int>(), test_allocator<PC>(0, 43));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::greater<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 43);
+    }
+
+    {
+    const P arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr), test_allocator<PC>(0, 44));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::less<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 44);
+    }
+
+    {
+    std::multimap m({ P{1,1L}, P{2,2L}, P{1,1L}, P{INT_MAX,1L}, P{3,1L} }, test_allocator<PC>(0, 45));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::less<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 45);
+    }
+
+    return 0;
+}
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp
new file mode 100644
index 00000000000..1c1eb2fd74f
--- /dev/null
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp
@@ -0,0 +1,107 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <algorithm> // std::equal
+#include <cassert>
+#include <climits> // INT_MAX
+#include <functional>
+#include <map>
+#include <type_traits>
+
+#include "test_allocator.h"
+
+using P = std::pair<int, long>;
+using PC = std::pair<const int, long>;
+using PCC = std::pair<const int, const long>;
+
+int main(int, char**)
+{
+    {
+    const PCC arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, const long>);
+    const PCC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const PCC arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr), std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, const long, std::greater<int>>);
+    const PCC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    const PCC arr[] = { {1,1L}, {2,2L}, {1,1L}, {INT_MAX,1L}, {3,1L} };
+    std::multimap m(std::begin(arr), std::end(arr), std::greater<int>(), test_allocator<PCC>(0, 42));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, const long, std::greater<int>, test_allocator<PCC>>);
+    const PCC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    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{ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} };
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long>);
+    const PC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::multimap m({ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} }, std::greater<int>());
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::greater<int>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    }
+
+    {
+    std::multimap m({ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} }, std::greater<int>(), test_allocator<PC>(0, 43));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::greater<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {INT_MAX,1L}, {3,1L}, {2,2L}, {1,1L}, {1,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 43);
+    }
+
+    {
+    std::multimap m({ PC{1,1L}, PC{2,2L}, PC{1,1L}, PC{INT_MAX,1L}, PC{3,1L} }, test_allocator<PC>(0, 45));
+
+    ASSERT_SAME_TYPE(decltype(m), std::multimap<int, long, std::less<int>, test_allocator<PC>>);
+    const PC expected_m[] = { {1,1L}, {1,1L}, {2,2L}, {3,1L}, {INT_MAX,1L} };
+    assert(std::equal(m.begin(), m.end(), std::begin(expected_m), std::end(expected_m)));
+    assert(m.get_allocator().get_id() == 45);
+    }
+
+    return 0;
+}