microsoft · StephanTLavavej · Jun 24, 2020 · May 12, 2020 · Jun 12, 2020 · Jun 12, 2020
diff --git a/llvm-project b/llvm-project
diff --git a/stl/inc/algorithm b/stl/inc/algorithm
diff --git a/stl/inc/xutility b/stl/inc/xutility
@@ -921,6 +921,28 @@ concept indirect_binary_predicate = indirectly_readable<_It1>
     && predicate<_Fn&, iter_reference_t<_It1>, iter_reference_t<_It2>>
     && predicate<_Fn&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
 
+// CONCEPT indirect_equivalence_relation
+template <class _Fn, class _It1, class _It2 = _It1>
+concept indirect_equivalence_relation = indirectly_readable<_It1>
+    && indirectly_readable<_It2>
+    && copy_constructible<_Fn>
+    && equivalence_relation<_Fn&, iter_value_t<_It1>&, iter_value_t<_It2>&>
+    && equivalence_relation<_Fn&, iter_value_t<_It1>&, iter_reference_t<_It2>>
+    && equivalence_relation<_Fn&, iter_reference_t<_It1>, iter_value_t<_It2>&>
+    && equivalence_relation<_Fn&, iter_reference_t<_It1>, iter_reference_t<_It2>>
+    && equivalence_relation<_Fn&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
+
+// CONCEPT indirect_strict_weak_order
+template <class _Fn, class _It1, class _It2 = _It1>
+concept indirect_strict_weak_order = indirectly_readable<_It1>
+    && indirectly_readable<_It2>
+    && copy_constructible<_Fn>
+    && strict_weak_order<_Fn&, iter_value_t<_It1>&, iter_value_t<_It2>&>
+    && strict_weak_order<_Fn&, iter_value_t<_It1>&, iter_reference_t<_It2>>
+    && strict_weak_order<_Fn&, iter_reference_t<_It1>, iter_value_t<_It2>&>
+    && strict_weak_order<_Fn&, iter_reference_t<_It1>, iter_reference_t<_It2>>
+    && strict_weak_order<_Fn&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
+
 // ALIAS TEMPLATE indirect_result_t
 template <class _Fn, class... _Its>
     requires (indirectly_readable<_Its> && ...)
@@ -987,6 +1009,11 @@ namespace ranges {
         concept _Can_swap_references = indirectly_readable<remove_reference_t<_Ty1>>
             && indirectly_readable<remove_reference_t<_Ty2>>
             && swappable_with<iter_reference_t<_Ty1>, iter_reference_t<_Ty2>>;
+
+        template <class _Ty1, class _Ty2>
+        concept _Symmetric_indirectly_movable_storable =
+               indirectly_movable_storable<remove_reference_t<_Ty1>, remove_reference_t<_Ty2>>
+            && indirectly_movable_storable<remove_reference_t<_Ty2>, remove_reference_t<_Ty1>>;
         // clang-format on
 
         template <class _Xty, class _Yty>
@@ -1001,15 +1028,13 @@ namespace ranges {
         private:
             enum class _St { _None, _Custom, _Swap, _Exchange };
 
-            // clang-format off
             template <class _Ty1, class _Ty2>
             _NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
                 if constexpr (_Has_ADL<_Ty1, _Ty2>) {
                     return {_St::_Custom, noexcept(iter_swap(_STD declval<_Ty1>(), _STD declval<_Ty2>()))};
                 } else if constexpr (_Can_swap_references<_Ty1, _Ty2>) {
                     return {_St::_Swap, noexcept(_RANGES swap(*_STD declval<_Ty1>(), *_STD declval<_Ty2>()))};
-                } else if constexpr (indirectly_movable_storable<remove_reference_t<_Ty1>, remove_reference_t<_Ty2>>
-                    && indirectly_movable_storable<remove_reference_t<_Ty2>, remove_reference_t<_Ty1>>) {
+                } else if constexpr (_Symmetric_indirectly_movable_storable<_Ty1, _Ty2>) {
                     constexpr auto _Nothrow = noexcept(
                         *_STD declval<_Ty1>() = _Iter_exchange_move(_STD declval<_Ty1>(), _STD declval<_Ty2>()));
                     return {_St::_Exchange, _Nothrow};
@@ -1022,6 +1047,7 @@ namespace ranges {
             static constexpr _Choice_t<_St> _Choice = _Choose<_Ty1, _Ty2>();
 
         public:
+            // clang-format off
             template <class _Ty1, class _Ty2>
                 requires (_Choice<_Ty1, _Ty2>._Strategy != _St::_None)
             constexpr void operator()(_Ty1&& _Val1, _Ty2&& _Val2) const noexcept(_Choice<_Ty1, _Ty2>._No_throw) {
@@ -3261,6 +3287,19 @@ namespace ranges {
     // VARIABLE ranges::prev
     inline constexpr _Prev_fn prev{_Not_quite_object::_Construct_tag{}};
 
+    // FUNCTION TEMPLATE _Find_last_iterator
+    template <forward_iterator _It, sentinel_for<_It> _Se>
+    _NODISCARD constexpr _It _Find_last_iterator(
+        const _It& _First, const _Se& _Last, const iter_difference_t<_It> _Count) {
+        // Find the iterator in [_First, _Last) (of length _Count) which equals _Last
+        _STL_INTERNAL_CHECK(_RANGES distance(_First, _Last) == _Count);
+        if constexpr (is_same_v<_It, _Se>) {
+            return _Last;
+        } else {
+            return _RANGES next(_First, _Count);
+        }
+    }
+
     // STRUCT ranges::equal_to
     struct equal_to {
         // clang-format off
@@ -5346,7 +5385,7 @@ _NODISCARD _Iter_diff_t<_FwdIt> count(
     _ExPo&& _Exec, const _FwdIt _First, const _FwdIt _Last, const _Ty& _Val) noexcept; // terminates
 #endif // _HAS_CXX17
 
-// FUNCTION TEMPLATE is_permutation
+// FUNCTION TEMPLATE _Check_match_counts
 template <class _InIt, class _Ty, class _Pr>
 _NODISCARD constexpr _InIt _Find_pr(_InIt _First, const _InIt _Last, const _Ty& _Val, _Pr _Pred) {
     for (; _First != _Last; ++_First) {
@@ -5427,114 +5466,6 @@ _NODISCARD _CONSTEXPR20 bool _Check_match_counts(
     return true;
 }
 
-template <class _FwdIt1, class _FwdIt2, class _Pr>
-_NODISCARD _CONSTEXPR20 bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _Pr _Pred) {
-    // test if [_First1, _Last1) == permuted [_First2, ...), using _Pred
-    for (; _First1 != _Last1; ++_First1, (void) ++_First2) { // trim matching prefix
-        if (!_Pred(*_First1, *_First2)) {
-            // found first inequality, check match counts in suffix
-            //
-            // narrowing _Iter_diff_t<_FwdIt1> to _Iter_diff_t<_FwdIt2> is OK because if the second range is shorter
-            // than the first, the user already triggered UB
-            auto _Last2 = _STD next(_First2, static_cast<_Iter_diff_t<_FwdIt2>>(_STD distance(_First1, _Last1)));
-            return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
-        }
-    }
-
-    return true;
-}
-
-template <class _FwdIt1, class _FwdIt2, class _Pr>
-_NODISCARD _CONSTEXPR20 bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _Pr _Pred) {
-    // test if [_First1, _Last1) == permuted [_First2, ...), using _Pred
-    _Adl_verify_range(_First1, _Last1);
-    const auto _UFirst1 = _Get_unwrapped(_First1);
-    const auto _ULast1  = _Get_unwrapped(_Last1);
-    const auto _UFirst2 = _Get_unwrapped_n(_First2, _Idl_distance<_FwdIt1>(_UFirst1, _ULast1));
-    return _Is_permutation_unchecked(_UFirst1, _ULast1, _UFirst2, _Pass_fn(_Pred));
-}
-
-template <class _FwdIt1, class _FwdIt2>
-_NODISCARD _CONSTEXPR20 bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2) {
-    // test if [_First1, _Last1) == permuted [_First2, ...)
-    return _STD is_permutation(_First1, _Last1, _First2, equal_to<>());
-}
-
-template <class _FwdIt1, class _FwdIt2, class _Pr>
-_CONSTEXPR20 bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred,
-    forward_iterator_tag, forward_iterator_tag) {
-    // test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred, arbitrary iterators
-    for (;;) { // trim matching prefix
-        if (_First1 == _Last1) {
-            return _First2 == _Last2;
-        }
-
-        if (_First2 == _Last2) {
-            return false;
-        }
-
-        if (!_Pred(*_First1, *_First2)) { // found first inequality, check match counts in suffix
-            break;
-        }
-
-        ++_First1;
-        ++_First2;
-    }
-
-    auto _Next1 = _First1;
-    auto _Next2 = _First2;
-    for (;;) { // check for same lengths
-        if (_Next1 == _Last1) {
-            if (_Next2 == _Last2) {
-                return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
-            }
-
-            return false; // sequence 1 is shorter than sequence 2, not a permutation
-        }
-
-        if (_Next2 == _Last2) {
-            return false; // sequence 1 is longer than sequence 2, not a permutation
-        }
-
-        ++_Next1;
-        ++_Next2;
-    }
-}
-
-template <class _FwdIt1, class _FwdIt2, class _Pr>
-_CONSTEXPR20 bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred,
-    random_access_iterator_tag, random_access_iterator_tag) {
-    // test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred, random-access iterators
-    if (_Last1 - _First1 != _Last2 - _First2) {
-        return false;
-    }
-
-    for (; _First1 != _Last1; ++_First1, (void) ++_First2) { // trim matching prefix
-        if (!_Pred(*_First1, *_First2)) {
-            // found first inequality, check match counts in suffix
-            return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
-        }
-    }
-
-    return true;
-}
-
-template <class _FwdIt1, class _FwdIt2, class _Pr>
-_NODISCARD _CONSTEXPR20 bool is_permutation(
-    _FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred) {
-    // test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred
-    _Adl_verify_range(_First1, _Last1);
-    _Adl_verify_range(_First2, _Last2);
-    return _Is_permutation_unchecked(_Get_unwrapped(_First1), _Get_unwrapped(_Last1), _Get_unwrapped(_First2),
-        _Get_unwrapped(_Last2), _Pass_fn(_Pred), _Iter_cat_t<_FwdIt1>(), _Iter_cat_t<_FwdIt2>());
-}
-
-template <class _FwdIt1, class _FwdIt2>
-_NODISCARD _CONSTEXPR20 bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2) {
-    // test if [_First1, _Last1) == permuted [_First2, _Last2)
-    return _STD is_permutation(_First1, _Last1, _First2, _Last2, equal_to<>());
-}
-
 // FUNCTION TEMPLATE reverse
 #if _HAS_IF_CONSTEXPR
 template <class _BidIt>

diff --git a/tests/libcxx/expected_results.txt b/tests/libcxx/expected_results.txt
@@ -583,11 +583,11 @@ std/containers/sequences/array/array.fill/fill.fail.cpp FAIL
 std/containers/sequences/array/array.swap/swap.fail.cpp FAIL
 
 # STL bug: VSO-207715 We reject array<NoDefault, 0>.
-std/containers/sequences/array/array.cons/default.pass.cpp FAIL
 std/containers/sequences/array/array.cons/implicit_copy.pass.cpp FAIL
+std/containers/sequences/array/array.cons/initialization.pass.cpp FAIL
 std/containers/sequences/array/array.data/data_const.pass.cpp FAIL
 std/containers/sequences/array/array.data/data.pass.cpp FAIL
-std/containers/sequences/array/begin.pass.cpp FAIL
+std/containers/sequences/array/iterators.pass.cpp FAIL
 
 # STL bug: string_view doesn't enforce "non-array trivial standard-layout", related to LWG-3034.
 std/strings/string.view/char.bad.fail.cpp:0 FAIL

diff --git a/tests/libcxx/magic_comments.txt b/tests/libcxx/magic_comments.txt
@@ -1,6 +1,6 @@
+// REQUIRES: c++03
+// REQUIRES: c++03 || c++11 || c++14
+// REQUIRES: c++03 || c++11 || c++14 || c++17
 // REQUIRES: c++11
 // REQUIRES: c++11 || c++14
-// REQUIRES: c++98 || c++03
-// REQUIRES: c++98 || c++03 || c++11 || c++14
-// REQUIRES: c++98 || c++03 || c++11 || c++14 || c++17
 // UNSUPPORTED: c++14, c++17, c++2a
diff --git a/tests/libcxx/skipped_tests.txt b/tests/libcxx/skipped_tests.txt
@@ -583,11 +583,11 @@ containers\sequences\array\array.fill\fill.fail.cpp
 containers\sequences\array\array.swap\swap.fail.cpp
 
 # STL bug: VSO-207715 We reject array<NoDefault, 0>.
-containers\sequences\array\array.cons\default.pass.cpp
 containers\sequences\array\array.cons\implicit_copy.pass.cpp
+containers\sequences\array\array.cons\initialization.pass.cpp
 containers\sequences\array\array.data\data_const.pass.cpp
 containers\sequences\array\array.data\data.pass.cpp
-containers\sequences\array\begin.pass.cpp
+containers\sequences\array\iterators.pass.cpp
 
 # STL bug: string_view doesn't enforce "non-array trivial standard-layout", related to LWG-3034.
 strings\string.view\char.bad.fail.cpp

diff --git a/tests/std/test.lst b/tests/std/test.lst
@@ -249,6 +249,7 @@ tests\P0896R4_ranges_alg_find_if
 tests\P0896R4_ranges_alg_find_if_not
 tests\P0896R4_ranges_alg_for_each
 tests\P0896R4_ranges_alg_for_each_n
+tests\P0896R4_ranges_alg_is_permutation
 tests\P0896R4_ranges_alg_mismatch
 tests\P0896R4_ranges_alg_move
 tests\P0896R4_ranges_alg_none_of

diff --git a/tests/std/tests/P0896R4_ranges_alg_is_permutation/env.lst b/tests/std/tests/P0896R4_ranges_alg_is_permutation/env.lst
@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\concepts_matrix.lst