From cfda24cd81bcafc1c3ae0f7ea2eac5796f3fe9e8 Mon Sep 17 00:00:00 2001
From: Yong Gyu Lee <cosgenio@gmail.com>
Date: Sun, 29 Sep 2024 13:57:15 +0900
Subject: [PATCH] Update span.cc

---
 test/span.cc | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/test/span.cc b/test/span.cc
index 4d168b80..a087d1be 100644
--- a/test/span.cc
+++ b/test/span.cc
@@ -6,6 +6,7 @@
 #include <vector>
 
 #include "preview/algorithm.h"
+#include "preview/array.h"
 #include "preview/ranges.h"
 
 namespace ranges = preview::ranges;
@@ -114,3 +115,97 @@ TEST(VERSIONED(Span), deduction_guides) {
 }
 
 #endif // C++17
+
+#if PREVIEW_CXX_VERSION >= 20
+
+#include <span>
+
+TEST(VERSIONED(Span), std_span_compat) {
+  const auto arr = preview::to_array({1, 2, 3, 4, 5});
+
+  static_assert(std::is_convertible_v<preview::span<int>, preview::span<int>> ==
+                std::is_convertible_v<preview::span<int>,     std::span<int>>, "");
+  static_assert(std::is_convertible_v<preview::span<unsigned int>, preview::span<int>> ==
+                std::is_convertible_v<preview::span<unsigned int>,     std::span<int>>, "");
+  static_assert(std::is_convertible_v<preview::span<int>, preview::span<unsigned int>> ==
+                std::is_convertible_v<preview::span<int>,     std::span<unsigned int>>, "");
+
+  static_assert(std::is_convertible_v<preview::span<int, 5>, preview::span<int>> ==
+                std::is_convertible_v<preview::span<int, 5>,     std::span<int>>, "");
+  static_assert(std::is_convertible_v<preview::span<unsigned int, 5>, preview::span<int>> ==
+                std::is_convertible_v<preview::span<unsigned int, 5>,     std::span<int>>, "");
+  static_assert(std::is_convertible_v<preview::span<int, 5>, preview::span<unsigned int>> ==
+                std::is_convertible_v<preview::span<int, 5>,     std::span<unsigned int>>, "");
+
+  static_assert(std::is_convertible_v<preview::span<int>, preview::span<int, 5>> ==
+                std::is_convertible_v<preview::span<int>,     std::span<int, 5>>, "");
+  static_assert(std::is_convertible_v<preview::span<unsigned int>, preview::span<int, 5>> ==
+                std::is_convertible_v<preview::span<unsigned int>,     std::span<int, 5>>, "");
+  static_assert(std::is_convertible_v<preview::span<int>, preview::span<unsigned int, 5>> ==
+                std::is_convertible_v<preview::span<int>,     std::span<unsigned int, 5>>, "");
+
+  static_assert(std::is_convertible_v<preview::span<int, 5>, preview::span<int, 5>> ==
+                std::is_convertible_v<preview::span<int, 5>,     std::span<int, 5>>, "");
+  static_assert(std::is_convertible_v<preview::span<unsigned int, 5>, preview::span<int, 5>> ==
+                std::is_convertible_v<preview::span<unsigned int, 5>,     std::span<int, 5>>, "");
+  static_assert(std::is_convertible_v<preview::span<int, 5>, preview::span<unsigned int, 5>> ==
+                std::is_convertible_v<preview::span<int, 5>,     std::span<unsigned int, 5>>, "");
+
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int>, preview::span<int>> ==
+                preview::is_explicitly_convertible_v<preview::span<int>,     std::span<int>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<unsigned int>, preview::span<int>> ==
+                preview::is_explicitly_convertible_v<preview::span<unsigned int>,     std::span<int>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int>, preview::span<unsigned int>> ==
+                preview::is_explicitly_convertible_v<preview::span<int>,     std::span<unsigned int>>, "");
+
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int, 5>, preview::span<int>> ==
+                preview::is_explicitly_convertible_v<preview::span<int, 5>,     std::span<int>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<unsigned int, 5>, preview::span<int>> ==
+                preview::is_explicitly_convertible_v<preview::span<unsigned int, 5>,     std::span<int>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int, 5>, preview::span<unsigned int>> ==
+                preview::is_explicitly_convertible_v<preview::span<int, 5>,     std::span<unsigned int>>, "");
+
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int>, preview::span<int, 5>> ==
+                preview::is_explicitly_convertible_v<preview::span<int>,     std::span<int, 5>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<unsigned int>, preview::span<int, 5>> ==
+                preview::is_explicitly_convertible_v<preview::span<unsigned int>,     std::span<int, 5>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int>, preview::span<unsigned int, 5>> ==
+                preview::is_explicitly_convertible_v<preview::span<int>,     std::span<unsigned int, 5>>, "");
+
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int, 5>, preview::span<int, 5>> ==
+                preview::is_explicitly_convertible_v<preview::span<int, 5>,     std::span<int, 5>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<unsigned int, 5>, preview::span<int, 5>> ==
+                preview::is_explicitly_convertible_v<preview::span<unsigned int, 5>,     std::span<int, 5>>, "");
+  static_assert(preview::is_explicitly_convertible_v<preview::span<int, 5>, preview::span<unsigned int, 5>> ==
+                preview::is_explicitly_convertible_v<preview::span<int, 5>,     std::span<unsigned int, 5>>, "");
+
+  static_assert(std::is_constructible_v<preview::span<int>, preview::span<int>> ==
+                std::is_constructible_v<    std::span<int>, preview::span<int>>, "");
+  static_assert(std::is_constructible_v<preview::span<unsigned int>, preview::span<int>> ==
+                std::is_constructible_v<    std::span<unsigned int>, preview::span<int>>, "");
+  static_assert(std::is_constructible_v<preview::span<int>, preview::span<unsigned int>> ==
+                std::is_constructible_v<    std::span<int>, preview::span<unsigned int>>, "");
+
+  static_assert(std::is_constructible_v<preview::span<int, 5>, preview::span<int>> ==
+                std::is_constructible_v<    std::span<int, 5>, preview::span<int>>, "");
+  static_assert(std::is_constructible_v<preview::span<unsigned int, 5>, preview::span<int>> ==
+                std::is_constructible_v<    std::span<unsigned int, 5>, preview::span<int>>, "");
+  static_assert(std::is_constructible_v<preview::span<int, 5>, preview::span<unsigned int>> ==
+                std::is_constructible_v<    std::span<int, 5>, preview::span<unsigned int>>, "");
+
+  static_assert(std::is_constructible_v<preview::span<int>, preview::span<int, 5>> ==
+                std::is_constructible_v<    std::span<int>, preview::span<int, 5>>, "");
+  static_assert(std::is_constructible_v<preview::span<unsigned int>, preview::span<int, 5>> ==
+                std::is_constructible_v<    std::span<unsigned int>, preview::span<int, 5>>, "");
+  static_assert(std::is_constructible_v<preview::span<int>, preview::span<unsigned int, 5>> ==
+                std::is_constructible_v<    std::span<int>, preview::span<unsigned int, 5>>, "");
+
+  static_assert(std::is_constructible_v<preview::span<int, 5>, preview::span<int, 5>> ==
+                std::is_constructible_v<    std::span<int, 5>, preview::span<int, 5>>, "");
+  static_assert(std::is_constructible_v<preview::span<unsigned int, 5>, preview::span<int, 5>> ==
+                std::is_constructible_v<    std::span<unsigned int, 5>, preview::span<int, 5>>, "");
+  static_assert(std::is_constructible_v<preview::span<int, 5>, preview::span<unsigned int, 5>> ==
+                std::is_constructible_v<    std::span<int, 5>, preview::span<unsigned int, 5>>, "");
+}
+
+#endif // C++17