Author: ericwf
Date: Mon Jul 11 14:57:13 2016
New Revision: 275094
URL: http://llvm.org/viewvc/llvm-project?rev=275094&view=rev
Log:
Allow is_swappable to SFINAE on deleted/ambiguous swap functions
Modified:
libcxx/trunk/include/type_traits
libcxx/trunk/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
Modified: libcxx/trunk/include/type_traits
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/type_traits?rev=275094&r1=275093&r2=275094&view=diff
==============================================================================
--- libcxx/trunk/include/type_traits (original)
+++ libcxx/trunk/include/type_traits Mon Jul 11 14:57:13 2016
@@ -4446,15 +4446,20 @@ iter_swap(_ForwardIterator1 __a, _Forwar
namespace __detail
{
// ALL generic swap overloads MUST already have a declaration available at
this point.
-using _VSTD::swap;
-__nat swap(__any, __any);
template <class _Tp, class _Up = _Tp,
bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
struct __swappable_with
{
- typedef decltype(swap(_VSTD::declval<_Tp>(), _VSTD::declval<_Up>()))
__swap1;
- typedef decltype(swap(_VSTD::declval<_Up>(), _VSTD::declval<_Tp>()))
__swap2;
+ template <class _LHS, class _RHS>
+ static decltype(swap(_VSTD::declval<_LHS>(), _VSTD::declval<_RHS>()))
+ __test_swap(int);
+ template <class, class>
+ static __nat __test_swap(long);
+
+ // Extra parens are needed for the C++03 definition of decltype.
+ typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
+ typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
static const bool value = !is_same<__swap1, __nat>::value
&& !is_same<__swap2, __nat>::value;
Modified:
libcxx/trunk/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp?rev=275094&r1=275093&r2=275094&view=diff
==============================================================================
---
libcxx/trunk/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
(original)
+++
libcxx/trunk/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
Mon Jul 11 14:57:13 2016
@@ -49,8 +49,21 @@ struct M {
void swap(M&&, M&&) {}
+struct DeletedSwap {
+ friend void swap(DeletedSwap&, DeletedSwap&) = delete;
+};
+
} // namespace MyNS
+namespace MyNS2 {
+
+struct AmbiguousSwap {};
+
+template <class T>
+void swap(T&, T&) {}
+
+} // end namespace MyNS2
+
int main()
{
using namespace MyNS;
@@ -70,6 +83,14 @@ int main()
static_assert(!std::is_swappable<int() &>::value, "");
}
{
+ // test that a deleted swap is correctly handled.
+ static_assert(!std::is_swappable<DeletedSwap>::value, "");
+ }
+ {
+ // test that a swap with ambiguous overloads is handled correctly.
+ static_assert(!std::is_swappable<MyNS2::AmbiguousSwap>::value, "");
+ }
+ {
// test for presence of is_swappable_v
static_assert(std::is_swappable_v<int>, "");
static_assert(!std::is_swappable_v<M>, "");
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
