The test cover constructors introduced in [PATCH v2] libstdc++-v3:
Implement missing allocator-aware constructors for unordered containers,
so I will merge that after.
On Fri, Apr 18, 2025 at 5:18 PM Jonathan Wakely <jwakely....@gmail.com>
wrote:
>
>
> On Fri, 18 Apr 2025, 12:55 Tomasz Kamiński, <tkami...@redhat.com> wrote:
>
>> This implements part of LWG4223 that adjust the deduction guides for maps
>> types
>> (map, unordered_map, flat_map and non-unique equivalent) from "range",
>> such that
>> referience and cv qualification are stripped from the element of the
>> pair-like
>> value_type.
>>
>> In combination with r15-8296-gd50171bc07006d, the LWG4223 is fully
>> implemented now.
>>
>> libstdc++-v3/ChangeLog:
>>
>> * include/bits/ranges_base.h (__detail::__range_key_type):
>> Replace remove_const_t with remove_cvref_t.
>> (__detail::__range_mapped_type): Apply remove_cvref_t.
>> * include/bits/stl_iterator.h: (__detail::__iter_key_t):
>> Replace remove_const_t with __remove_cvref_t.
>> (__detail::__iter_val_t): Apply __remove_cvref_t.
>> * testsuite/23_containers/flat_map/1.cc: New tests.
>> * testsuite/23_containers/flat_multimap/1.cc: New tests.
>> * testsuite/23_containers/map/cons/deduction.cc: New tests.
>> * testsuite/23_containers/map/cons/from_range.cc: New tests.
>> * testsuite/23_containers/multimap/cons/deduction.cc: New tests.
>> * testsuite/23_containers/multimap/cons/from_range.cc: New tests.
>> * testsuite/23_containers/unordered_map/cons/deduction.cc: New
>> tests.
>> * testsuite/23_containers/unordered_map/cons/from_range.cc: New
>> tests.
>> * testsuite/23_containers/unordered_multimap/cons/deduction.cc:
>> New tests.
>> * testsuite/23_containers/unordered_multimap/cons/from_range.cc:
>> New tests.
>> ---
>> Desipite there being some discussion about this on reflector, I think we
>> should go ahead with this, to avoid creating maps of references/const
>> types.
>> As we are at the begining of development of 16, this seems like a good
>> time
>> to do it.
>> OK for trunk?
>>
>
> OK for trunk.
>
>
>
>>
>> libstdc++-v3/include/bits/ranges_base.h | 4 +-
>> libstdc++-v3/include/bits/stl_iterator.h | 11 +--
>> .../testsuite/23_containers/flat_map/1.cc | 21 +++---
>> .../23_containers/flat_multimap/1.cc | 21 +++---
>> .../23_containers/map/cons/deduction.cc | 46 +++++++++++++
>> .../23_containers/map/cons/from_range.cc | 8 +--
>> .../23_containers/multimap/cons/deduction.cc | 46 +++++++++++++
>> .../23_containers/multimap/cons/from_range.cc | 8 +--
>> .../unordered_map/cons/deduction.cc | 69 +++++++++++++++++++
>> .../unordered_map/cons/from_range.cc | 10 ++-
>> .../unordered_multimap/cons/deduction.cc | 69 +++++++++++++++++++
>> .../unordered_multimap/cons/from_range.cc | 10 +--
>> 12 files changed, 279 insertions(+), 44 deletions(-)
>>
>> diff --git a/libstdc++-v3/include/bits/ranges_base.h
>> b/libstdc++-v3/include/bits/ranges_base.h
>> index 488907da446..dde16498856 100644
>> --- a/libstdc++-v3/include/bits/ranges_base.h
>> +++ b/libstdc++-v3/include/bits/ranges_base.h
>> @@ -1103,11 +1103,11 @@ namespace __detail
>> // 4223. Deduction guides for maps are mishandling tuples and
>> references
>> template<ranges::input_range _Range>
>> using __range_key_type
>> - = remove_const_t<tuple_element_t<0,
>> ranges::range_value_t<_Range>>>;
>> + = remove_cvref_t<tuple_element_t<0,
>> ranges::range_value_t<_Range>>>;
>>
>> template<ranges::input_range _Range>
>> using __range_mapped_type
>> - = tuple_element_t<1, ranges::range_value_t<_Range>>;
>> + = remove_cvref_t<tuple_element_t<1,
>> ranges::range_value_t<_Range>>>;
>>
>> // The allocator's value_type for map-like containers.
>> template<ranges::input_range _Range>
>> diff --git a/libstdc++-v3/include/bits/stl_iterator.h
>> b/libstdc++-v3/include/bits/stl_iterator.h
>> index 9203a66b2ff..bed72955d0c 100644
>> --- a/libstdc++-v3/include/bits/stl_iterator.h
>> +++ b/libstdc++-v3/include/bits/stl_iterator.h
>> @@ -3086,8 +3086,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>> #if __cpp_deduction_guides >= 201606
>> // These helper traits are used for deduction guides
>> // of associative containers.
>> +
>> + // _GLIBCXX_RESOLVE_LIB_DEFECTS
>> + // 4223. Deduction guides for maps are mishandling tuples and
>> references
>> template<typename _InputIterator>
>> - using __iter_key_t = remove_const_t<
>> + using __iter_key_t = __remove_cvref_t<
>> #ifdef __glibcxx_tuple_like // >= C++23
>> tuple_element_t<0, typename
>> iterator_traits<_InputIterator>::value_type>>;
>> #else
>> @@ -3095,11 +3098,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>> #endif
>>
>> template<typename _InputIterator>
>> - using __iter_val_t
>> + using __iter_val_t = __remove_cvref_t<
>> #ifdef __glibcxx_tuple_like // >= C++23
>> - = tuple_element_t<1, typename
>> iterator_traits<_InputIterator>::value_type>;
>> + tuple_element_t<1, typename
>> iterator_traits<_InputIterator>::value_type>>;
>> #else
>> - = typename
>> iterator_traits<_InputIterator>::value_type::second_type;
>> + typename iterator_traits<_InputIterator>::value_type::second_type>;
>> #endif
>>
>> template<typename _T1, typename _T2>
>> diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
>> b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
>> index d9d88c4df6e..6105a2865c9 100644
>> --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
>> @@ -55,16 +55,17 @@ test_deduction_guide()
>> std::vector<long, __gnu_test::SimpleAllocator<long>>,
>> std::vector<float,
>> __gnu_test::SimpleAllocator<float>>>>);
>>
>> - // LWG4223: deduces flat_map<long, float const>, which in turn
>> instantiates
>> - // std::vector<cosnt float> that is ill-formed.
>> - // __gnu_test::test_input_range<std::pair<const long, const float>>
>> r2(0, 0);
>> - // std::flat_map it5(r2.begin(), r2.begin());
>> - // std::flat_map fr5(std::from_range, r2);
>> -
>> - // LWG4223: deduces flat_map<const long&, float&>
>> - //__gnu_test::test_input_range<std::pair<const long&, float&>> r3(0,
>> 0);
>> - // std::flat_map it6(r3.begin(), r3.begin());
>> - // std::flat_map fr6(std::from_range, r3);
>> + __gnu_test::test_input_range<std::pair<const long, const float>> r2(0,
>> 0);
>> + std::flat_map it5(r2.begin(), r2.begin());
>> + static_assert(std::is_same_v<decltype(it5), std::flat_map<long,
>> float>>);
>> + std::flat_map fr5(std::from_range, r2);
>> + static_assert(std::is_same_v<decltype(fr5), std::flat_map<long,
>> float>>);
>> +
>> + __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0, 0);
>> + std::flat_map it6(r3.begin(), r3.begin());
>> + static_assert(std::is_same_v<decltype(it6), std::flat_map<long,
>> float>>);
>> + std::flat_map fr6(std::from_range, r3);
>> + static_assert(std::is_same_v<decltype(fr6), std::flat_map<long,
>> float>>);
>>
>> __gnu_test::test_input_range<std::tuple<long, float>> r4(0, 0);
>> std::flat_map it7(r4.begin(), r4.begin());
>> diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
>> b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
>> index ff180bf1bdf..ac8b0e0d7d9 100644
>> --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
>> @@ -53,16 +53,17 @@ test_deduction_guide()
>> std::vector<long, __gnu_test::SimpleAllocator<long>>,
>> std::vector<float,
>> __gnu_test::SimpleAllocator<float>>>>);
>>
>> - // LWG4223: deduces flat_multimap<long, float const>, which in turn
>> instantiates
>> - // std::vector<cosnt float> that is ill-formed.
>> - // __gnu_test::test_input_range<std::pair<const long, const float>>
>> r2(0, 0);
>> - // std::flat_multimap it5(r2.begin(), r2.begin());
>> - // std::flat_multimap fr5(std::from_range, r2);
>> -
>> - // LWG4223: deduces flat_multimap<const long&, float&>
>> - //__gnu_test::test_input_range<std::pair<const long&, float&>> r3(0,
>> 0);
>> - // std::flat_multimap it6(r3.begin(), r3.begin());
>> - // std::flat_multimap fr6(std::from_range, r3);
>> + __gnu_test::test_input_range<std::pair<const long, const float>> r2(0,
>> 0);
>> + std::flat_multimap it5(r2.begin(), r2.begin());
>> + static_assert(std::is_same_v<decltype(it5), std::flat_multimap<long,
>> float>>);
>> + std::flat_multimap fr5(std::from_range, r2);
>> + static_assert(std::is_same_v<decltype(fr5), std::flat_multimap<long,
>> float>>);
>> +
>> + __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0, 0);
>> + std::flat_multimap it6(r3.begin(), r3.begin());
>> + static_assert(std::is_same_v<decltype(it6), std::flat_multimap<long,
>> float>>);
>> + std::flat_multimap fr6(std::from_range, r3);
>> + static_assert(std::is_same_v<decltype(fr6), std::flat_multimap<long,
>> float>>);
>>
>> __gnu_test::test_input_range<std::tuple<long, float>> r4(0, 0);
>> std::flat_multimap it7(r4.begin(), r4.begin());
>> diff --git a/libstdc++-v3/testsuite/23_containers/map/cons/deduction.cc
>> b/libstdc++-v3/testsuite/23_containers/map/cons/deduction.cc
>> index f8e6e6e8b99..194bff5bf78 100644
>> --- a/libstdc++-v3/testsuite/23_containers/map/cons/deduction.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/map/cons/deduction.cc
>> @@ -258,3 +258,49 @@ test_p1518r2()
>> std::map s2(std::move(m), p);
>> check_type<Map>(s2);
>> }
>> +
>> +struct MyPred
>> +{
>> + template<typename T, typename U>
>> + bool operator()(T const&, U const&) const;
>> +};
>> +
>> +template<typename K, typename V>
>> +constexpr bool test_lwg4223()
>> +{
>> + using KD = std::remove_cvref_t<K>;
>> + using VD = std::remove_cvref_t<V>;
>> + using Alloc = __gnu_test::SimpleAllocator<std::pair<const KD, VD>>;
>> +
>> + std::initializer_list<std::pair<K, V>> il = {};
>> + Alloc a;
>> + MyPred p;
>> +
>> + // The remove_cvref_t is not applied here.
>> + // static_assert(std::is_same_v<
>> + // decltype(std::map(il)),
>> + // std::map<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::map(il.begin(), il.end())),
>> + std::map<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::map(il.begin(), il.end(), p)),
>> + std::map<KD, VD, MyPred>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::map(il.begin(), il.end(), a)),
>> + std::map<KD, VD, std::less<KD>, Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::map(il.begin(), il.end(), p, a)),
>> + std::map<KD, VD, MyPred, Alloc>>);
>> +
>> + return true;
>> +}
>> +
>> +static_assert(test_lwg4223<const int, const float>());
>> +static_assert(test_lwg4223<int&, float&>());
>> +static_assert(test_lwg4223<int&&, float&&>());
>> +static_assert(test_lwg4223<const int&, const float&>());
>> diff --git a/libstdc++-v3/testsuite/23_containers/map/cons/from_range.cc
>> b/libstdc++-v3/testsuite/23_containers/map/cons/from_range.cc
>> index 9935f44aa0f..3a9fede0434 100644
>> --- a/libstdc++-v3/testsuite/23_containers/map/cons/from_range.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/map/cons/from_range.cc
>> @@ -43,11 +43,11 @@ test_deduction_guide()
>>
>> __gnu_test::test_input_range<std::pair<const long, const float>> r2(0,
>> 0);
>> std::map m5(std::from_range, r2);
>> - static_assert(std::is_same_v<decltype(m5), std::map<long, const
>> float>>);
>> + static_assert(std::is_same_v<decltype(m5), std::map<long, float>>);
>>
>> - // LWG4223: deduces map<const long&, float&>
>> - //__gnu_test::test_input_range<std::pair<const long&, float&>> r3(0,
>> 0);
>> - // std::map m6(std::from_range, r3);
>> + __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0, 0);
>> + std::map m6(std::from_range, r3);
>> + static_assert(std::is_same_v<decltype(m6), std::map<long, float>>);
>>
>> __gnu_test::test_input_range<std::tuple<long, float>> r4(0, 0);
>> std::map m7(std::from_range, r4);
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/multimap/cons/deduction.cc
>> b/libstdc++-v3/testsuite/23_containers/multimap/cons/deduction.cc
>> index f0699e2eefc..84754f3f561 100644
>> --- a/libstdc++-v3/testsuite/23_containers/multimap/cons/deduction.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/multimap/cons/deduction.cc
>> @@ -210,3 +210,49 @@ test_p1518r2()
>> std::multimap s2(std::move(m), p);
>> check_type<MMap>(s2);
>> }
>> +
>> +struct MyPred
>> +{
>> + template<typename T, typename U>
>> + bool operator()(T const&, U const&) const;
>> +};
>> +
>> +template<typename K, typename V>
>> +constexpr bool test_lwg4223()
>> +{
>> + using KD = std::remove_cvref_t<K>;
>> + using VD = std::remove_cvref_t<V>;
>> + using Alloc = __gnu_test::SimpleAllocator<std::pair<const KD, VD>>;
>> +
>> + std::initializer_list<std::pair<K, V>> il = {};
>> + Alloc a;
>> + MyPred p;
>> +
>> + // The remove_cvref_t is not applied here.
>> + // static_assert(std::is_same_v<
>> + // decltype(std::multimap(il)),
>> + // std::multimap<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::multimap(il.begin(), il.end())),
>> + std::multimap<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::multimap(il.begin(), il.end(), p)),
>> + std::multimap<KD, VD, MyPred>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::multimap(il.begin(), il.end(), a)),
>> + std::multimap<KD, VD, std::less<KD>, Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::multimap(il.begin(), il.end(), p, a)),
>> + std::multimap<KD, VD, MyPred, Alloc>>);
>> +
>> + return true;
>> +}
>> +
>> +static_assert(test_lwg4223<const int, const float>());
>> +static_assert(test_lwg4223<int&, float&>());
>> +static_assert(test_lwg4223<int&&, float&&>());
>> +static_assert(test_lwg4223<const int&, const float&>());
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/multimap/cons/from_range.cc
>> b/libstdc++-v3/testsuite/23_containers/multimap/cons/from_range.cc
>> index 4a8ea9fec7d..5907bab9878 100644
>> --- a/libstdc++-v3/testsuite/23_containers/multimap/cons/from_range.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/multimap/cons/from_range.cc
>> @@ -43,11 +43,11 @@ test_deduction_guide()
>>
>> __gnu_test::test_input_range<std::pair<const long, const float>> r2(0,
>> 0);
>> std::multimap m5(std::from_range, r2);
>> - static_assert(std::is_same_v<decltype(m5), std::multimap<long, const
>> float>>);
>> + static_assert(std::is_same_v<decltype(m5), std::multimap<long,
>> float>>);
>>
>> - // LWG4223: deduces multimap<const long&, float&>
>> - //__gnu_test::test_input_range<std::pair<const long&, float&>> r3(0,
>> 0);
>> - // std::multimap m6(std::from_range, r3);
>> + __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0, 0);
>> + std::multimap m6(std::from_range, r3);
>> + static_assert(std::is_same_v<decltype(m6), std::multimap<long,
>> float>>);
>>
>> __gnu_test::test_input_range<std::tuple<long, float>> r4(0, 0);
>> std::multimap m7(std::from_range, r4);
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/deduction.cc
>> b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/deduction.cc
>> index 8b69af896a2..e806de2045c 100644
>> --- a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/deduction.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/deduction.cc
>> @@ -162,3 +162,72 @@ test_p1518r2()
>> std::unordered_map s2(std::move(m), p);
>> check_type<UMap>(s2);
>> }
>> +
>> +struct MyHash
>> +{
>> + template<typename T>
>> + std::size_t operator()(T const&) const;
>> +};
>> +
>> +struct MyPred
>> +{
>> + template<typename T, typename U>
>> + bool operator()(T const&, U const&) const;
>> +};
>> +
>> +template<typename K, typename V>
>> +constexpr bool test_lwg4223()
>> +{
>> + using KD = std::remove_cvref_t<K>;
>> + using VD = std::remove_cvref_t<V>;
>> + using Alloc = __gnu_test::SimpleAllocator<std::pair<const KD, VD>>;
>> +
>> + std::initializer_list<std::pair<K, V>> il = {};
>> + Alloc a;
>> + MyHash h;
>> + MyPred p;
>> +
>> + // The remove_cvref_t is not applied here.
>> + // static_assert(std::is_same_v<
>> + // decltype(std::unordered_map(il)),
>> + // std::unordered_map<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end())),
>> + std::unordered_map<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), 0)),
>> + std::unordered_map<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), 0, h)),
>> + std::unordered_map<KD, VD, MyHash>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), 0, h, p)),
>> + std::unordered_map<KD, VD, MyHash, MyPred>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), a)),
>> + std::unordered_map<KD, VD, std::hash<KD>, std::equal_to<KD>,
>> Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), 0, a)),
>> + std::unordered_map<KD, VD, std::hash<KD>, std::equal_to<KD>,
>> Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), 0, h, a)),
>> + std::unordered_map<KD, VD, MyHash, std::equal_to<KD>, Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_map(il.begin(), il.end(), 0, h, p, a)),
>> + std::unordered_map<KD, VD, MyHash, MyPred, Alloc>>);
>> +
>> + return true;
>> +}
>> +
>> +static_assert(test_lwg4223<const int, const float>());
>> +static_assert(test_lwg4223<int&, float&>());
>> +static_assert(test_lwg4223<int&&, float&&>());
>> +static_assert(test_lwg4223<const int&, const float&>());
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/from_range.cc
>> b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/from_range.cc
>> index 36efc2de5a3..04479a5e54d 100644
>> ---
>> a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/from_range.cc
>> +++
>> b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/from_range.cc
>> @@ -78,13 +78,11 @@ test_deduction_guide()
>>
>> __gnu_test::test_input_range<std::pair<const long, const float>> r2(0,
>> 0);
>> std::unordered_map m9(std::from_range, r2);
>> - static_assert(std::is_same_v<
>> - decltype(m9),
>> - std::unordered_map<long, const float>>);
>> + static_assert(std::is_same_v<decltype(m9), std::unordered_map<long,
>> float>>);
>>
>> - // LWG4223: deduces map<const long&, float&>
>> - // __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0,
>> 0);
>> - // std::unordered_map m10(std::from_range, r3);
>> + __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0, 0);
>> + std::unordered_map m10(std::from_range, r3);
>> + static_assert(std::is_same_v<decltype(m10), std::unordered_map<long,
>> float>>);
>>
>> __gnu_test::test_input_range<std::tuple<long, float>> r4(0, 0);
>> std::unordered_map m11(std::from_range, r4);
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/deduction.cc
>> b/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/deduction.cc
>> index e7e535b527a..786e5030bb2 100644
>> ---
>> a/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/deduction.cc
>> +++
>> b/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/deduction.cc
>> @@ -171,3 +171,72 @@ test_p1518r2()
>> std::unordered_multimap s2(std::move(m), p);
>> check_type<UMMap>(s2);
>> }
>> +
>> +struct MyHash
>> +{
>> + template<typename T>
>> + std::size_t operator()(T const&) const;
>> +};
>> +
>> +struct MyPred
>> +{
>> + template<typename T, typename U>
>> + bool operator()(T const&, U const&) const;
>> +};
>> +
>> +template<typename K, typename V>
>> +constexpr bool test_lwg4223()
>> +{
>> + using KD = std::remove_cvref_t<K>;
>> + using VD = std::remove_cvref_t<V>;
>> + using Alloc = __gnu_test::SimpleAllocator<std::pair<const KD, VD>>;
>> +
>> + std::initializer_list<std::pair<K, V>> il = {};
>> + Alloc a;
>> + MyHash h;
>> + MyPred p;
>> +
>> + // The remove_cvref_t is not applied here.
>> + // static_assert(std::is_same_v<
>> + // decltype(std::unordered_multimap(il)),
>> + // std::unordered_multimap<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end())),
>> + std::unordered_multimap<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), 0)),
>> + std::unordered_multimap<KD, VD>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), 0, h)),
>> + std::unordered_multimap<KD, VD, MyHash>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), 0, h, p)),
>> + std::unordered_multimap<KD, VD, MyHash, MyPred>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), a)),
>> + std::unordered_multimap<KD, VD, std::hash<KD>, std::equal_to<KD>,
>> Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), 0, a)),
>> + std::unordered_multimap<KD, VD, std::hash<KD>, std::equal_to<KD>,
>> Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), 0, h, a)),
>> + std::unordered_multimap<KD, VD, MyHash, std::equal_to<KD>, Alloc>>);
>> +
>> + static_assert(std::is_same_v<
>> + decltype(std::unordered_multimap(il.begin(), il.end(), 0, h, p, a)),
>> + std::unordered_multimap<KD, VD, MyHash, MyPred, Alloc>>);
>> +
>> + return true;
>> +}
>> +
>> +static_assert(test_lwg4223<const int, const float>());
>> +static_assert(test_lwg4223<int&, float&>());
>> +static_assert(test_lwg4223<int&&, float&&>());
>> +static_assert(test_lwg4223<const int&, const float&>());
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/from_range.cc
>> b/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/from_range.cc
>> index b551df49f3e..4567bd8aa91 100644
>> ---
>> a/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/from_range.cc
>> +++
>> b/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/from_range.cc
>> @@ -86,11 +86,13 @@ test_deduction_guide()
>> std::unordered_multimap m9(std::from_range, r2);
>> static_assert(std::is_same_v<
>> decltype(m9),
>> - std::unordered_multimap<long, const float>>);
>> + std::unordered_multimap<long, float>>);
>>
>> - // LWG4223: deduces map<const long&, float&>
>> - // __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0,
>> 0);
>> - // std::unordered_multimap m10(std::from_range, r3);
>> + __gnu_test::test_input_range<std::pair<const long&, float&>> r3(0, 0);
>> + std::unordered_multimap m10(std::from_range, r3);
>> + static_assert(std::is_same_v<
>> + decltype(m10),
>> + std::unordered_multimap<long, float>>);
>>
>> __gnu_test::test_input_range<std::tuple<long, float>> r4(0, 0);
>> std::unordered_multimap m11(std::from_range, r4);
>> --
>> 2.49.0
>>
>>
