Add <optional> header.

This patch is largely thanks to Casey Carter @ Microsoft. He did the initial
work of porting our experimental implementation and tests over to namespace
std.

llvm-svn: 283977

1 files changed, 137 insertions, 0 deletions

diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
new file mode 100644
index 00000000000..4830fe90d67
--- /dev/null
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
@@ -0,0 +1,137 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <optional>
+
+// template <class U>
+//   constexpr EXPLICIT optional(U&& u);
+
+#include <optional>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+#include "archetypes.hpp"
+#include "test_convertible.hpp"
+
+
+using std::optional;
+
+struct ImplicitThrow
+{
+    constexpr ImplicitThrow(int x) { if (x != -1) TEST_THROW(6);}
+};
+
+struct ExplicitThrow
+{
+    constexpr explicit ExplicitThrow(int x) { if (x != -1) TEST_THROW(6);}
+};
+
+
+template <class To, class From>
+constexpr bool implicit_conversion(optional<To>&& opt, const From& v)
+{
+    using O = optional<To>;
+    static_assert(test_convertible<O, From>(), "");
+    static_assert(!test_convertible<O, void*>(), "");
+    static_assert(!test_convertible<O, From, int>(), "");
+    return opt && *opt == static_cast<To>(v);
+}
+
+template <class To, class Input, class Expect>
+constexpr bool explicit_conversion(Input&& in, const Expect& v)
+{
+    using O = optional<To>;
+    static_assert(std::is_constructible<O, Input>::value, "");
+    static_assert(!std::is_convertible<Input, O>::value, "");
+    static_assert(!std::is_constructible<O, void*>::value, "");
+    static_assert(!std::is_constructible<O, Input, int>::value, "");
+    optional<To> opt(std::forward<Input>(in));
+    return opt && *opt == static_cast<To>(v);
+}
+
+void test_implicit()
+{
+    {
+        using T = long long;
+        static_assert(implicit_conversion<long long>(42, 42), "");
+    }
+    {
+        using T = long double;
+        static_assert(implicit_conversion<long double>(3.14, 3.14), "");
+    }
+    {
+        using T = TrivialTestTypes::TestType;
+        static_assert(implicit_conversion<T>(42, 42), "");
+    }
+    {
+        using T = TestTypes::TestType;
+        assert(implicit_conversion<T>(3, T(3)));
+    }
+#ifndef TEST_HAS_NO_EXCEPTIONS
+    {
+        try {
+            using T = ImplicitThrow;
+            optional<T> t = 42;
+            assert(false);
+        } catch (int) {
+        }
+    }
+#endif
+}
+
+void test_explicit() {
+    {
+        using T = ExplicitTrivialTestTypes::TestType;
+        using O = optional<T>;
+        static_assert(explicit_conversion<T>(42, 42), "");
+    }
+    {
+        using T = ExplicitConstexprTestTypes::TestType;
+        using O = optional<T>;
+        static_assert(explicit_conversion<T>(42, 42), "");
+        static_assert(!std::is_convertible<int, T>::value, "");
+    }
+    {
+        using T = ExplicitTestTypes::TestType;
+        using O = optional<T>;
+        T::reset();
+        {
+            assert(explicit_conversion<T>(42, 42));
+            assert(T::alive == 0);
+        }
+        T::reset();
+        {
+            optional<T> t(42);
+            assert(T::alive == 1);
+            assert(T::value_constructed == 1);
+            assert(T::move_constructed == 0);
+            assert(T::copy_constructed == 0);
+            assert(t.value().value == 42);
+        }
+        assert(T::alive == 0);
+    }
+#ifndef TEST_HAS_NO_EXCEPTIONS
+    {
+        try {
+            using T = ExplicitThrow;
+            optional<T> t(42);
+            assert(false);
+        } catch (int) {
+        }
+    }
+#endif
+}
+
+int main() {
+    test_implicit();
+    test_explicit();
+}
\ No newline at end of file