[libcxx-commits] [libcxx] [libc++][spaceship] Implements X::iterator container requirements. (PR #99343)

[Louis Dionne via libcxx-commits]

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@@ -0,0 +1,93 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <span>
+
+// class iterator
+
+#include <cassert>
+#include <concepts>
+#include <iterator>
+#include <span>
+#include <string>
+#include <version> // __cpp_lib_ranges_as_const is not defined in span.
+
+#include "test_macros.h"
+
+template <class T>
+TEST_CONSTEXPR void test_type() {
+#
+
+  using C = std::span<T>;
+  typename C::iterator ii1{}, ii2{};
+  typename C::iterator ii4 = ii1;
+  // TODO Test against C++23 after implementing
+  // P2278R4 cbegin should always return a constant iterator
+#ifdef __cpp_lib_ranges_as_const
+  typename C::const_iterator cii{};
+#endif
+  assert(ii1 == ii2);
+  assert(ii1 == ii4);
+#ifdef __cpp_lib_ranges_as_const
+  assert(ii1 == cii);
+#endif
+
+  assert(!(ii1 != ii2));
+#ifdef __cpp_lib_ranges_as_const
+  assert(!(ii1 != cii));
+#endif
+
+  T v;
+  C c{&v, 1};
+  assert(c.begin() == std::begin(c));
+  assert(c.rbegin() == std::rbegin(c));
+#ifdef __cpp_lib_ranges_as_const
+  assert(c.cbegin() == std::cbegin(c));
+  assert(c.crbegin() == std::crbegin(c));
+#endif
+
+  assert(c.end() == std::end(c));
+  assert(c.rend() == std::rend(c));
+#ifdef __cpp_lib_ranges_as_const
+  assert(c.cend() == std::cend(c));
+  assert(c.crend() == std::crend(c));
+#endif
+
+  assert(std::begin(c) != std::end(c));
+  assert(std::rbegin(c) != std::rend(c));
+#ifdef __cpp_lib_ranges_as_const
+  assert(std::cbegin(c) != std::cend(c));
+  assert(std::crbegin(c) != std::crend(c));
+#endif
+
+  // P1614 + LWG3352
+  std::same_as<std::strong_ordering> decltype(auto) r1 = ii1 <=> ii2;
+  assert(r1 == std::strong_ordering::equal);
+
+#ifdef __cpp_lib_ranges_as_const
+  std::same_as<std::strong_ordering> decltype(auto) r2 = cii <=> ii2;
+  assert(r2 == std::strong_ordering::equal);
+#endif
+}
+
+TEST_CONSTEXPR bool test() {
----------------
ldionne wrote:

```suggestion
constexpr bool test() {
```

https://github.com/llvm/llvm-project/pull/99343