[libcxx] Fix LWG Issue #2367 - Fixing std::tuple and std::pair's default constructors.
Summary: This patch implements the solution for LWG Issue #2367. See http://cplusplus.github.io/LWG/lwg-active.html#2367
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D13750
llvm-svn: 256325
diff --git a/libcxx/include/__config b/libcxx/include/__config
index fa0c40e..f141f4f 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -305,6 +305,10 @@
#define _LIBCPP_UNUSED __attribute__((__unused__))
+#if !(__has_feature(cxx_default_function_template_args))
+#define _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
+#endif
+
#if !(__has_feature(cxx_defaulted_functions))
#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#endif // !(__has_feature(cxx_defaulted_functions))
@@ -474,6 +478,7 @@
#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
#define _LIBCPP_HAS_NO_DECLTYPE
+#define _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
#define _LIBCPP_HAS_NO_NULLPTR
@@ -487,13 +492,12 @@
#else // __GXX_EXPERIMENTAL_CXX0X__
#if _GNUC_VER < 403
+#define _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
-#endif
-
-#if _GNUC_VER < 403
#define _LIBCPP_HAS_NO_STATIC_ASSERT
#endif
+
#if _GNUC_VER < 404
#define _LIBCPP_HAS_NO_DECLTYPE
#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
@@ -565,6 +569,7 @@
#define _LIBCPP_NORETURN __attribute__((noreturn))
#define _LIBCPP_UNUSED
+#define _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
diff --git a/libcxx/include/utility b/libcxx/include/utility
index 4d0191c..c9f5785 100644
--- a/libcxx/include/utility
+++ b/libcxx/include/utility
@@ -288,6 +288,12 @@
// pair(const pair&) = default;
// pair(pair&&) = default;
+#ifndef _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
+ template <bool _Dummy = true, class = typename enable_if<
+ __dependent_type<is_default_constructible<_T1>, _Dummy>::value &&
+ __dependent_type<is_default_constructible<_T2>, _Dummy>::value
+ >::type>
+#endif
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11