Experimental support for a meaningful __is_swappable<T>::value. This does not appear to be strictly needed for correct functioning of the library. If it causes any problems, I'd rather pull it sooner rather than later.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@132421 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/array b/include/array
index 188d24d..888fac2 100644
--- a/include/array
+++ b/include/array
@@ -270,7 +270,11 @@
template <class _Tp, size_t _Size>
_LIBCPP_INLINE_VISIBILITY inline
-void
+typename enable_if
+<
+ __is_swappable<_Tp>::value,
+ void
+>::type
swap(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
_NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
{
diff --git a/include/tuple b/include/tuple
index 49f220d..c075e42 100644
--- a/include/tuple
+++ b/include/tuple
@@ -587,7 +587,11 @@
template <class ..._Tp>
inline _LIBCPP_INLINE_VISIBILITY
-void
+typename enable_if
+<
+ __all<__is_swappable<_Tp>::value...>::value,
+ void
+>::type
swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
_NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
{__t.swap(__u);}
diff --git a/include/utility b/include/utility
index d0ad1ec..6934c1e 100644
--- a/include/utility
+++ b/include/utility
@@ -377,7 +377,12 @@
template <class _T1, class _T2>
inline _LIBCPP_INLINE_VISIBILITY
-void
+typename enable_if
+<
+ __is_swappable<_T1>::value &&
+ __is_swappable<_T2>::value,
+ void
+>::type
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
_NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
__is_nothrow_swappable<_T2>::value))