[libc++][test] Fix assumptions that std::array iterators are pointers (llvm#74430)

Found while running libc++'s tests with MSVC's STL, where `std::array`
iterators are never pointers.

Most of these changes are reasonably self-explanatory (the `std::array`s
are right there, and the sometimes-slightly-wrapped raw pointer types
are a short distance away). A couple of changes are less obvious:

In `libcxx/test/std/containers/from_range_helpers.h`, `wrap_input()` is
called with `Iter` types that are constructible from raw pointers. It's
also sometimes called with an `array` as the `input`, so the first
overload was implicitly assuming that `array` iterators are pointers. We
can fix this assumption by providing a dedicated overload for `array`,
just like the one for `vector` immediately below. Finally,
`from_range_helpers.h` should explicitly include both `<array>` and
`<vector>`, even though they were apparently being dragged in already.

In `libcxx/test/std/containers/views/views.span/span.cons/iterator_sentinel.pass.cpp`,
fix `throw_operator_minus`. The error was pretty complicated, caused by
the concepts machinery noticing that `value_type` and `element_type`
were inconsistent. In the template instantiation context, you can see
the critical detail that `throw_operator_minus<std::_Array_iterator>` is
being formed.

Fortunately, the fix is extremely simple. To produce `element_type`
(which retains any cv-qualification, unlike `value_type`), we shouldn't
attempt to `remove_pointer` with the iterator type `It`. Instead, we've
already obtained the `reference` type, so we can `remove_reference_t`.
(This is modern code, where we have access to the alias templates, so I
saw no reason to use the older verbose form.)

Author: StephanTLavavej

libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/pstl.replace.pass.cpp

@@ -29,35 +29,35 @@ struct Test {
   void operator()(ExecutionPolicy&& policy) {
     { // simple test
       std::array a = {1, 2, 3, 4, 5, 6, 7, 8};
-      std::replace(policy, Iter(std::begin(a)), Iter(std::end(a)), 3, 6);
+      std::replace(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), 3, 6);
       assert((a == std::array{1, 2, 6, 4, 5, 6, 7, 8}));
     }
 
     { // empty range works
       std::array<int, 0> a = {};
-      std::replace(policy, Iter(std::begin(a)), Iter(std::end(a)), 3, 6);
+      std::replace(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), 3, 6);
     }
 
     { // non-empty range without a match works
       std::array a = {1, 2};
-      std::replace(policy, Iter(std::begin(a)), Iter(std::end(a)), 3, 6);
+      std::replace(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), 3, 6);
     }
 
     { // single element range works
       std::array a = {3};
-      std::replace(policy, Iter(std::begin(a)), Iter(std::end(a)), 3, 6);
+      std::replace(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), 3, 6);
       assert((a == std::array{6}));
     }
 
     { // two element range works
       std::array a = {3, 4};
-      std::replace(policy, Iter(std::begin(a)), Iter(std::end(a)), 3, 6);
+      std::replace(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), 3, 6);
       assert((a == std::array{6, 4}));
     }
 
     { // multiple matching elements work
       std::array a = {1, 2, 3, 4, 3, 3, 5, 6, 3};
-      std::replace(policy, Iter(std::begin(a)), Iter(std::end(a)), 3, 9);
+      std::replace(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), 3, 9);
       assert((a == std::array{1, 2, 9, 4, 9, 9, 5, 6, 9}));
     }
 

libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/pstl.replace_copy.pass.cpp

@@ -32,40 +32,40 @@ struct Test {
     { // simple test
       std::array a = {1, 2, 3, 4, 5, 6, 7, 8};
       std::array<int, a.size()> out;
-      std::replace_copy(policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), 3, 6);
+      std::replace_copy(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), Iter(std::data(out)), 3, 6);
       assert((out == std::array{1, 2, 6, 4, 5, 6, 7, 8}));
     }
 
     { // empty range works
       std::array<int, 0> a = {};
-      std::replace_copy(policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(a)), 3, 6);
+      std::replace_copy(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), Iter(std::data(a)), 3, 6);
     }
 
     { // non-empty range without a match works
       std::array a = {1, 2};
       std::array<int, a.size()> out;
-      std::replace_copy(policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(out.data()), 3, 6);
+      std::replace_copy(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), Iter(out.data()), 3, 6);
       assert((out == std::array{1, 2}));
     }
 
     { // single element range works
       std::array a = {3};
       std::array<int, a.size()> out;
-      std::replace_copy(policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), 3, 6);
+      std::replace_copy(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), Iter(std::data(out)), 3, 6);
       assert((out == std::array{6}));
     }
 
     { // two element range works
       std::array a = {3, 4};
       std::array<int, a.size()> out;
-      std::replace_copy(policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), 3, 6);
+      std::replace_copy(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), Iter(std::data(out)), 3, 6);
       assert((out == std::array{6, 4}));
     }
 
     { // multiple matching elements work
       std::array a = {1, 2, 3, 4, 3, 3, 5, 6, 3};
       std::array<int, a.size()> out;
-      std::replace_copy(policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), 3, 9);
+      std::replace_copy(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), Iter(std::data(out)), 3, 9);
       assert((out == std::array{1, 2, 9, 4, 9, 9, 5, 6, 9}));
     }
 

libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/pstl.replace_copy_if.pass.cpp

@@ -34,45 +34,75 @@ struct Test {
       std::array a = {1, 2, 3, 4, 5, 6, 7, 8};
       std::array<int, a.size()> out;
       std::replace_copy_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), [](int i) { return i == 3; }, 6);
+          policy,
+          Iter(std::data(a)),
+          Iter(std::data(a) + std::size(a)),
+          Iter(std::data(out)),
+          [](int i) { return i == 3; },
+          6);
       assert((out == std::array{1, 2, 6, 4, 5, 6, 7, 8}));
     }
 
     { // empty range works
       std::array<int, 0> a = {};
       std::replace_copy_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(a)), [](int i) { return i == 3; }, 6);
+          policy,
+          Iter(std::data(a)),
+          Iter(std::data(a) + std::size(a)),
+          Iter(std::data(a)),
+          [](int i) { return i == 3; },
+          6);
     }
 
     { // non-empty range without a match works
       std::array a = {1, 2};
       std::array<int, a.size()> out;
       std::replace_copy_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(out.data()), [](int i) { return i == 3; }, 6);
+          policy,
+          Iter(std::data(a)),
+          Iter(std::data(a) + std::size(a)),
+          Iter(out.data()),
+          [](int i) { return i == 3; },
+          6);
       assert((out == std::array{1, 2}));
     }
 
     { // single element range works
       std::array a = {3};
       std::array<int, a.size()> out;
       std::replace_copy_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), [](int i) { return i == 3; }, 6);
+          policy,
+          Iter(std::data(a)),
+          Iter(std::data(a) + std::size(a)),
+          Iter(std::data(out)),
+          [](int i) { return i == 3; },
+          6);
       assert((out == std::array{6}));
     }
 
     { // two element range works
       std::array a = {3, 4};
       std::array<int, a.size()> out;
       std::replace_copy_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), [](int i) { return i == 3; }, 6);
+          policy,
+          Iter(std::data(a)),
+          Iter(std::data(a) + std::size(a)),
+          Iter(std::data(out)),
+          [](int i) { return i == 3; },
+          6);
       assert((out == std::array{6, 4}));
     }
 
     { // multiple matching elements work
       std::array a = {1, 2, 3, 4, 3, 3, 5, 6, 3};
       std::array<int, a.size()> out;
       std::replace_copy_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), Iter(std::begin(out)), [](int i) { return i == 3; }, 9);
+          policy,
+          Iter(std::data(a)),
+          Iter(std::data(a) + std::size(a)),
+          Iter(std::data(out)),
+          [](int i) { return i == 3; },
+          9);
       assert((out == std::array{1, 2, 9, 4, 9, 9, 5, 6, 9}));
     }
 

libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/pstl.replace_if.pass.cpp

@@ -30,38 +30,40 @@ struct Test {
     { // simple test
       std::array a = {1, 2, 3, 4, 5, 6, 7, 8};
       std::replace_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), [](int i) { return i == 3 || i == 7; }, 6);
+          policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [](int i) { return i == 3 || i == 7; }, 6);
       assert((a == std::array{1, 2, 6, 4, 5, 6, 6, 8}));
     }
 
     { // empty range works
       std::array<int, 0> a = {};
       std::replace_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), [](int) { return false; }, 6);
+          policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [](int) { return false; }, 6);
     }
 
     { // non-empty range without a match works
       std::array a = {1, 2};
-      std::replace_if(policy, Iter(std::begin(a)), Iter(std::end(a)), [](int) { return false; }, 6);
+      std::replace_if(
+          policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [](int) { return false; }, 6);
     }
 
     { // single element range works
       std::array a = {3};
       std::replace_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), [](int i) { return i == 3; }, 6);
+          policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [](int i) { return i == 3; }, 6);
       assert((a == std::array{6}));
     }
 
     { // two element range works
       std::array a = {3, 4};
       std::replace_if(
-          policy, Iter(std::begin(a)), Iter(std::end(a)), [](int i) { return i == 3; }, 6);
+          policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [](int i) { return i == 3; }, 6);
       assert((a == std::array{6, 4}));
     }
 
     { // multiple matching elements work
       std::array a = {1, 2, 3, 4, 3, 3, 5, 6, 3};
-      std::replace_if(policy, Iter(std::begin(a)), Iter(std::end(a)), [](int i) { return i == 3; }, 9);
+      std::replace_if(
+          policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [](int i) { return i == 3; }, 9);
       assert((a == std::array{1, 2, 9, 4, 9, 9, 5, 6, 9}));
     }
 

libcxx/test/std/algorithms/alg.sorting/alg.merge/pstl.merge.pass.cpp

@@ -53,24 +53,36 @@ struct Test {
       std::array<int, 0> a;
       std::array<int, 0> b;
       std::array<int, std::size(a) + std::size(b)> out;
-      std::merge(
-          policy, Iter1(std::begin(a)), Iter1(std::end(a)), Iter2(std::begin(b)), Iter2(std::end(b)), std::begin(out));
+      std::merge(policy,
+                 Iter1(std::data(a)),
+                 Iter1(std::data(a) + std::size(a)),
+                 Iter2(std::data(b)),
+                 Iter2(std::data(b) + std::size(b)),
+                 std::begin(out));
     }
     { // check that it works with the first range being empty
       std::array<int, 0> a;
       int b[] = {2, 4, 6, 8, 10};
       std::array<int, std::size(a) + std::size(b)> out;
-      std::merge(
-          policy, Iter1(std::begin(a)), Iter1(std::end(a)), Iter2(std::begin(b)), Iter2(std::end(b)), std::begin(out));
+      std::merge(policy,
+                 Iter1(std::data(a)),
+                 Iter1(std::data(a) + std::size(a)),
+                 Iter2(std::begin(b)),
+                 Iter2(std::end(b)),
+                 std::begin(out));
       assert((out == std::array{2, 4, 6, 8, 10}));
     }
 
     { // check that it works with the second range being empty
       int a[] = {2, 4, 6, 8, 10};
       std::array<int, 0> b;
       std::array<int, std::size(a) + std::size(b)> out;
-      std::merge(
-          policy, Iter1(std::begin(a)), Iter1(std::end(a)), Iter2(std::begin(b)), Iter2(std::end(b)), std::begin(out));
+      std::merge(policy,
+                 Iter1(std::begin(a)),
+                 Iter1(std::end(a)),
+                 Iter2(std::data(b)),
+                 Iter2(std::data(b) + std::size(b)),
+                 std::begin(out));
       assert((out == std::array{2, 4, 6, 8, 10}));
     }
 

libcxx/test/std/algorithms/alg.sorting/alg.three.way/lexicographical_compare_three_way.pass.cpp

@@ -27,8 +27,8 @@
 
 template <typename Iter1, typename Iter2, typename C1, typename C2, typename Order>
 constexpr void test_lexicographical_compare(C1 a, C2 b, Order expected) {
-  std::same_as<Order> decltype(auto) result =
-      std::lexicographical_compare_three_way(Iter1{a.begin()}, Iter1{a.end()}, Iter2{b.begin()}, Iter2{b.end()});
+  std::same_as<Order> decltype(auto) result = std::lexicographical_compare_three_way(
+      Iter1{a.data()}, Iter1{a.data() + a.size()}, Iter2{b.data()}, Iter2{b.data() + b.size()});
   assert(expected == result);
 }
 

libcxx/test/std/algorithms/alg.sorting/alg.three.way/lexicographical_compare_three_way_comp.pass.cpp

@@ -56,8 +56,8 @@ static_assert(has_lexicographical_compare<decltype(compare_int_result)>);
 
 template <typename Iter1, typename Iter2, typename C1, typename C2, typename Order, typename Comparator>
 constexpr void test_lexicographical_compare(C1 a, C2 b, Comparator comp, Order expected) {
-  std::same_as<Order> decltype(auto) result =
-      std::lexicographical_compare_three_way(Iter1{a.begin()}, Iter1{a.end()}, Iter2{b.begin()}, Iter2{b.end()}, comp);
+  std::same_as<Order> decltype(auto) result = std::lexicographical_compare_three_way(
+      Iter1{a.data()}, Iter1{a.data() + a.size()}, Iter2{b.data()}, Iter2{b.data() + b.size()}, comp);
   assert(expected == result);
 }
 

libcxx/test/std/containers/from_range_helpers.h

@@ -9,9 +9,11 @@
 #ifndef SUPPORT_FROM_RANGE_HELPERS_H
 #define SUPPORT_FROM_RANGE_HELPERS_H
 
+#include <array>
 #include <cstddef>
 #include <iterator>
 #include <type_traits>
+#include <vector>
 
 #include "min_allocator.h"
 #include "test_allocator.h"
@@ -34,6 +36,13 @@ constexpr auto wrap_input(Range&& input) {
   return std::ranges::subrange(std::move(b), std::move(e));
 }
 
+template <class Iter, class Sent, class T, std::size_t N>
+constexpr auto wrap_input(std::array<T, N>& input) {
+  auto b = Iter(input.data());
+  auto e = Sent(Iter(input.data() + input.size()));
+  return std::ranges::subrange(std::move(b), std::move(e));
+}
+
 template <class Iter, class Sent, class T>
 constexpr auto wrap_input(std::vector<T>& input) {
   auto b = Iter(input.data());

libcxx/test/std/containers/views/views.span/span.cons/iterator_sentinel.pass.cpp

@@ -71,7 +71,7 @@ class throw_operator_minus {
   typedef typename std::iterator_traits<It>::difference_type difference_type;
   typedef It pointer;
   typedef typename std::iterator_traits<It>::reference reference;
-  typedef typename std::remove_pointer<It>::type element_type;
+  typedef std::remove_reference_t<reference> element_type;
 
   throw_operator_minus() : it_() {}
   explicit throw_operator_minus(It it) : it_(it) {}

libcxx/test/std/ranges/range.adaptors/range.chunk.by/range.chunk.by.iter/compare.pass.cpp

@@ -31,15 +31,15 @@ constexpr void test() {
   using ChunkByView     = std::ranges::chunk_by_view<Underlying, std::ranges::less_equal>;
   using ChunkByIterator = std::ranges::iterator_t<ChunkByView>;
 
-  auto make_chunk_by_view = [](auto begin, auto end) {
-    View view{Iterator(begin), Sentinel(Iterator(end))};
+  auto make_chunk_by_view = [](auto& arr) {
+    View view{Iterator(arr.data()), Sentinel(Iterator(arr.data() + arr.size()))};
     return ChunkByView(std::move(view), std::ranges::less_equal{});
   };
 
   // Test operator==
   {
     std::array array{0, 1, 2};
-    ChunkByView view  = make_chunk_by_view(array.begin(), array.end());
+    ChunkByView view  = make_chunk_by_view(array);
     ChunkByIterator i = view.begin();
     ChunkByIterator j = view.begin();
 
@@ -52,7 +52,7 @@ constexpr void test() {
   // Test synthesized operator!=
   {
     std::array array{0, 1, 2};
-    ChunkByView view  = make_chunk_by_view(array.begin(), array.end());
+    ChunkByView view  = make_chunk_by_view(array);
     ChunkByIterator i = view.begin();
     ChunkByIterator j = view.begin();
 
@@ -65,7 +65,7 @@ constexpr void test() {
   // Test operator== with std::default_sentinel_t
   {
     std::array array{0, 1, 2};
-    ChunkByView view  = make_chunk_by_view(array.begin(), array.end());
+    ChunkByView view  = make_chunk_by_view(array);
     ChunkByIterator i = view.begin();
 
     std::same_as<bool> decltype(auto) result = (i == std::default_sentinel);
@@ -77,7 +77,7 @@ constexpr void test() {
   // Test synthesized operator!= with std::default_sentinel_t
   {
     std::array array{0, 1, 2};
-    ChunkByView view  = make_chunk_by_view(array.begin(), array.end());
+    ChunkByView view  = make_chunk_by_view(array);
     ChunkByIterator i = view.begin();
 
     std::same_as<bool> decltype(auto) result = (i != std::default_sentinel);