Provide swappable traits (p0185r1)

2016-06-16  Daniel Kruegler  <daniel.kruegler@gmail.com>

	Provide swappable traits (p0185r1)
	* include/std/type_traits (is_swappable, is_nothrow_swappable,
	is_swappable_with, is_nothrow_swappable_with, is_swappable_v,
	is_nothrow_swappable_v, is_swappable_with_v,
	is_nothrow_swappable_with_v): New.
	* include/bits/stl_pair.h: Use it as per p0185r1.
	* include/bits/stl_queue.h: Likewise.
	* include/bits/stl_stack.h: Likewise.
	* include/bits/unique_ptr.h: Likewise.
	* include/std/tuple: Likewise.
	* include/std/array: Likewise. Fix zero-size member swap.
	* include/bits/hashtable.h: Use __and_.
	* testsuite/20_util/is_nothrow_swappable/requirements/
	explicit_instantiation.cc: Change test options to std=gnu++17.
	* testsuite/20_util/is_nothrow_swappable/requirements/typedefs.cc:
	Likewise.
	* testsuite/20_util/is_nothrow_swappable/value.cc: Likewise.
	* testsuite/20_util/is_swappable/requirements/
	explicit_instantiation.cc: Likewise.
	* testsuite/20_util/is_swappable/requirements/typedefs.cc: Likewise.
	* testsuite/20_util/is_swappable/value.cc: Likewise.
	* testsuite/20_util/is_nothrow_swappable/requirements/
	explicit_instantiation_ext.cc: New.
	* testsuite/20_util/is_nothrow_swappable/requirements/typedefs_ext.cc:
	New.
	* testsuite/20_util/is_nothrow_swappable/value.h: New.
	* testsuite/20_util/is_nothrow_swappable/value_ext.cc: New.
	* testsuite/20_util/is_nothrow_swappable_with/requirements/
	explicit_instantiation.cc: New.
	* testsuite/20_util/is_nothrow_swappable_with/requirements/typedefs.cc:
	New.
	* testsuite/20_util/is_nothrow_swappable_with/value.cc: New.
	* testsuite/20_util/is_swappable/requirements/
	explicit_instantiation_ext.cc: New.
	* testsuite/20_util/is_swappable/requirements/typedefs_ext.cc: New.
	* testsuite/20_util/is_swappable/value.h: New.
	* testsuite/20_util/is_swappable/value_ext.cc: New.
	* testsuite/20_util/is_swappable_with/requirements/
	explicit_instantiation.cc: New.
	* testsuite/20_util/is_swappable_with/requirements/typedefs.cc: New.
	* testsuite/20_util/is_swappable_with/value.cc: New.
	* testsuite/23_containers/array/tuple_interface/get_neg.cc: Adjust
	dg-error line numbers.
	* testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc:
	Likewise.

From-SVN: r237531

1 files changed, 14 insertions, 2 deletions

diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array
index ee46f68..73d2669 100644
--- a/libstdc++-v3/include/std/array
+++ b/libstdc++-v3/include/std/array
@@ -48,6 +48,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     struct __array_traits
     {
       typedef _Tp _Type[_Nm];
+      typedef __is_swappable<_Tp> _Is_swappable;
+      typedef __is_nothrow_swappable<_Tp> _Is_nothrow_swappable;
 
       static constexpr _Tp&
       _S_ref(const _Type& __t, std::size_t __n) noexcept
@@ -62,6 +64,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
    struct __array_traits<_Tp, 0>
    {
      struct _Type { };
+     typedef true_type _Is_swappable;
+     typedef true_type _Is_nothrow_swappable;
 
      static constexpr _Tp&
      _S_ref(const _Type&, std::size_t) noexcept
@@ -114,7 +118,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       void
       swap(array& __other)
-      noexcept(__is_nothrow_swappable<_Tp>::value)
+      noexcept(_AT_Type::_Is_nothrow_swappable::value)
       { std::swap_ranges(begin(), end(), __other.begin()); }
 
       // Iterators.
@@ -271,7 +275,15 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
   // Specialized algorithms.
   template<typename _Tp, std::size_t _Nm>
-    inline void
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<
+      _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::_Is_swappable::value
+    >::type
+#else
+    void
+#endif
     swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
     noexcept(noexcept(__one.swap(__two)))
     { __one.swap(__two); }