From 5a1fb8e18457ef08e22175ba12e9f61553db2436 Mon Sep 17 00:00:00 2001
From: Werner Henze <werner.henze+gitcommits@posteo.de>
Date: Wed, 18 Dec 2024 21:10:23 +0100
Subject: [PATCH] this commits adds tests that should fail, but don't

---
 tests/byte_tests.cpp     | 39 +++++++++++++++++++++++++++++++++++++++
 tests/pointers_tests.cpp | 21 +++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/tests/byte_tests.cpp b/tests/byte_tests.cpp
index 1d2052a..0308992 100644
--- a/tests/byte_tests.cpp
+++ b/tests/byte_tests.cpp
@@ -19,6 +19,9 @@
 #define GSL_USE_STD_BYTE 0
 #include <gsl/byte> // for to_byte, to_integer, byte, operator&, ope...
 
+#include <type_traits>
+#include <utility>
+
 using namespace std;
 using namespace gsl;
 
@@ -128,6 +131,42 @@ TEST(byte_tests, aliasing)
     EXPECT_TRUE(res == i);
 }
 
+//  These are regressions, should be fixed.
+template <typename U, typename = void>
+static constexpr bool LShiftCompilesFor = false;
+template <typename U>
+static constexpr bool LShiftCompilesFor<
+    U, std::void_t<decltype(gsl::operator<< <float, void>(declval<gsl::byte>(), declval<U>()))>> = true;
+static_assert(LShiftCompilesFor<float>, "LShiftCompilesFor<float>");
+
+template <typename U, typename = void>
+static constexpr bool RShiftCompilesFor = false;
+template <typename U>
+static constexpr bool RShiftCompilesFor<
+    U, std::void_t<decltype(gsl::operator>> <U, void>(declval<gsl::byte>(), declval<U>()))>> = true;
+static_assert(RShiftCompilesFor<float>, "RShiftCompilesFor<float>");
+
+template <typename U, typename = void>
+static constexpr bool LShiftAssignCompilesFor = false;
+template <typename U>
+static constexpr bool LShiftAssignCompilesFor<
+    U, std::void_t<decltype(gsl::operator<<= <U, void>(declval<gsl::byte&>(), declval<U>()))>> = true;
+static_assert(LShiftAssignCompilesFor<float>, "LShiftAssignCompilesFor<float>");
+
+template <typename U, typename = void>
+static constexpr bool RShiftAssignCompilesFor = false;
+template <typename U>
+static constexpr bool RShiftAssignCompilesFor<
+    U, std::void_t<decltype(gsl::operator>>= <U, void>(declval<gsl::byte&>(), declval<U>()))>> = true;
+static_assert(RShiftAssignCompilesFor<float>, "RShiftAssignCompilesFor<float>");
+
+template <typename U, typename = void>
+static constexpr bool ToIntegerCompilesFor = false;
+template <typename U>
+static constexpr bool ToIntegerCompilesFor<
+    U, std::void_t<decltype(gsl::to_integer<U, void>(gsl::byte{}))>> = true;
+static_assert(ToIntegerCompilesFor<float>, "ToIntegerCompilesFor<float>");
+
 } // namespace
 
 #ifdef CONFIRM_COMPILATION_ERRORS
diff --git a/tests/pointers_tests.cpp b/tests/pointers_tests.cpp
index fc9fb45..cbb476b 100644
--- a/tests/pointers_tests.cpp
+++ b/tests/pointers_tests.cpp
@@ -3,6 +3,11 @@
 #include <gsl/pointers>
 
 #include <memory>
+#include <type_traits>
+#include <utility>
+
+namespace
+{
 
 TEST(pointers_test, swap)
 {
@@ -19,3 +24,19 @@ TEST(pointers_test, swap)
     EXPECT_TRUE(*b == 0);
 }
 
+//  These are regressions, should be fixed.
+struct NotMovable
+{
+    NotMovable(NotMovable&&) = delete;
+    NotMovable& operator=(NotMovable&&) = delete;
+};
+template <typename U, typename = void>
+static constexpr bool SwapCompilesFor = false;
+template <typename U>
+static constexpr bool SwapCompilesFor<
+    U, std::void_t<decltype(gsl::swap<U, void>(std::declval<gsl::not_null<U>&>(),
+                                               std::declval<gsl::not_null<U>&>()))>> =
+    true;
+static_assert(SwapCompilesFor<NotMovable>, "SwapCompilesFor<NotMovable>");
+
+} // namespace