Add <variant> tests but disable them for libc++

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287728 91177308-0d34-0410-b5e6-96231b3b80d8

test/support/variant_test_helpers.hpp

@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#ifndef SUPPORT_VARIANT_TEST_HELPERS_HPP
+#define SUPPORT_VARIANT_TEST_HELPERS_HPP
+
+#include <type_traits>
+#include <utility>
+#include <cassert>
+
+#include "test_macros.h"
+
+#if TEST_STD_VER <= 14
+#error This file requires C++17
+#endif
+
+// FIXME: Currently the variant<T&> tests are disabled using this macro.
+#define TEST_VARIANT_HAS_NO_REFERENCES
+
+#ifndef TEST_HAS_NO_EXCEPTIONS
+struct CopyThrows {
+  CopyThrows() = default;
+  CopyThrows(CopyThrows const&) { throw 42; }
+  CopyThrows& operator=(CopyThrows const&) { throw 42; }
+};
+
+struct MoveThrows {
+  static int alive;
+  MoveThrows() { ++alive; }
+  MoveThrows(MoveThrows const&) {++alive;}
+  MoveThrows(MoveThrows&&) {  throw 42; }
+  MoveThrows& operator=(MoveThrows const&) { return *this; }
+  MoveThrows& operator=(MoveThrows&&) { throw 42; }
+  ~MoveThrows() { --alive; }
+};
+
+int MoveThrows::alive = 0;
+
+struct MakeEmptyT {
+  static int alive;
+  MakeEmptyT() { ++alive; }
+  MakeEmptyT(MakeEmptyT const&) {
+      ++alive;
+      // Don't throw from the copy constructor since variant's assignment
+      // operator performs a copy before committing to the assignment.
+  }
+  MakeEmptyT(MakeEmptyT &&) {
+      throw 42;
+  }
+  MakeEmptyT& operator=(MakeEmptyT const&) {
+      throw 42;
+  }
+  MakeEmptyT& operator=(MakeEmptyT&&) {
+      throw 42;
+  }
+   ~MakeEmptyT() { --alive; }
+};
+static_assert(std::is_swappable_v<MakeEmptyT>, ""); // required for test
+
+int MakeEmptyT::alive = 0;
+
+template <class Variant>
+void makeEmpty(Variant& v) {
+    Variant v2(std::in_place_type<MakeEmptyT>);
+    try {
+        v = v2;
+        assert(false);
+    }  catch (...) {
+        assert(v.valueless_by_exception());
+    }
+}
+#endif // TEST_HAS_NO_EXCEPTIONS
+
+
+#endif // SUPPORT_VARIANT_TEST_HELPERS_HPP