Index: libcxx/include/future
===================================================================
--- libcxx/include/future
+++ libcxx/include/future
@@ -2126,10 +2126,10 @@
     __p_ = promise<result_type>();
 }
 
-template <class _Callable>
+template <class _Rp, class... _ArgTypes>
 inline _LIBCPP_INLINE_VISIBILITY
 void
-swap(packaged_task<_Callable>& __x, packaged_task<_Callable>& __y) _NOEXCEPT
+swap(packaged_task<_Rp(_ArgTypes...)>& __x, packaged_task<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
 {
     __x.swap(__y);
 }
Index: libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp
===================================================================
--- libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp
+++ libcxx/test/std/thread/futures/futures.task/futures.task.nonmembers/swap.pass.cpp
@@ -51,6 +51,13 @@
         assert(!p0.valid());
         assert(!p.valid());
     }
+    {
+        std::packaged_task<double(int, char)> p0;
+        std::packaged_task<double(int, char)> p;
+        swap<double, int, char>(p, p0);
+        assert(!p0.valid());
+        assert(!p.valid());
+    }
 
   return 0;
 }