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, 53 insertions, 0 deletions

diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
new file mode 100644
index 00000000000..b54a08f5575
--- /dev/null
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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 T> constexpr bool operator==(const optional<T>& x, const T& v);
+// template <class T> constexpr bool operator==(const T& v, const optional<T>& x);
+
+#include <optional>
+
+using std::optional;
+
+struct X
+{
+    int i_;
+
+    constexpr X(int i) : i_(i) {}
+};
+
+constexpr bool operator == ( const X &lhs, const X &rhs )
+    { return lhs.i_ == rhs.i_ ; }
+
+int main()
+{
+    {
+    typedef X T;
+    typedef optional<T> O;
+
+    constexpr T val(2);
+    constexpr O o1;       // disengaged
+    constexpr O o2{1};    // engaged
+    constexpr O o3{val};  // engaged
+
+    static_assert ( !(o1 == T(1)), "" );
+    static_assert (  (o2 == T(1)), "" );
+    static_assert ( !(o3 == T(1)), "" );
+    static_assert (  (o3 == T(2)), "" );
+    static_assert (  (o3 == val),  "" );
+
+    static_assert ( !(T(1) == o1), "" );
+    static_assert (  (T(1) == o2), "" );
+    static_assert ( !(T(1) == o3), "" );
+    static_assert (  (T(2) == o3), "" );
+    static_assert (  (val  == o3), "" );
+    }
+}