From 2cd516e049e4fc1dd8e33c6990841f5b6300ef6c Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Mon, 25 Jul 2016 00:15:29 +0000
Subject: [PATCH] Make swap_noexcept.pass.cpp tests more portable. Patch from
 STL@microsoft.com.

See D21820 for more information (https://reviews.llvm.org/D21820).

llvm-svn: 276590
---
 .../map/map.special/swap_noexcept.pass.cpp    | 28 +++++-------
 .../multimap.special/swap_noexcept.pass.cpp   | 30 +++++--------
 .../multiset.special/swap_noexcept.pass.cpp   | 28 +++++-------
 .../set/set.special/swap_noexcept.pass.cpp    | 28 +++++-------
 .../priqueue.special/swap_noexcept.pass.cpp   |  4 +-
 .../queue.special/swap_noexcept.pass.cpp      |  4 +-
 .../stack.special/swap_noexcept.pass.cpp      |  4 +-
 .../deque.special/swap_noexcept.pass.cpp      | 18 +++-----
 .../forwardlist.spec/swap_noexcept.pass.cpp   | 18 +++-----
 .../list/list.special/swap_noexcept.pass.cpp  | 18 +++-----
 .../vector.bool/swap_noexcept.pass.cpp        | 18 +++-----
 .../vector.special/swap_noexcept.pass.cpp     | 18 +++-----
 .../unord.map.swap/swap_noexcept.pass.cpp     | 43 +++++++------------
 .../swap_noexcept.pass.cpp                    | 43 +++++++------------
 .../swap_noexcept.pass.cpp                    | 43 +++++++------------
 .../unord.set.swap/swap_noexcept.pass.cpp     | 43 +++++++------------
 .../string.special/swap_noexcept.pass.cpp     | 15 +++----
 17 files changed, 148 insertions(+), 255 deletions(-)

diff --git a/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp
index cbbf4577ce62..84907945a90e 100644
--- a/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.special/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <map>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -96,51 +97,42 @@ int main()
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
         typedef std::map<MoveOnly, MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::map<MoveOnly, MoveOnly, std::less<MoveOnly>, test_allocator<V>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::map<MoveOnly, MoveOnly, std::less<MoveOnly>, other_allocator<V>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::map<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for comp
     typedef std::map<MoveOnly, MoveOnly, some_comp <MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for comp
     typedef std::map<MoveOnly, MoveOnly, some_comp <MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for comp
     typedef std::map<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for comp
     typedef std::map<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for comp
     typedef std::map<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc3<V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp
index ffc71b0eeb92..ecc9c7ef5fd4 100644
--- a/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.special/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <map>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -96,51 +97,42 @@ int main()
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
         typedef std::multimap<MoveOnly, MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::multimap<MoveOnly, MoveOnly, std::less<MoveOnly>, test_allocator<V>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::multimap<MoveOnly, MoveOnly, std::less<MoveOnly>, other_allocator<V>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::multimap<MoveOnly, MoveOnly, some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for comp
     typedef std::multimap<MoveOnly, MoveOnly, some_comp <MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for comp
     typedef std::multimap<MoveOnly, MoveOnly, some_comp <MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for comp
     typedef std::multimap<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for comp
     typedef std::multimap<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for comp
-    typedef std::map<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc3<V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    typedef std::multimap<MoveOnly, MoveOnly, some_comp2<MoveOnly>, some_alloc3<V>> C;
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp
index 87639943a0b5..89fabef0a3a0 100644
--- a/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.special/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <set>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -95,51 +96,42 @@ int main()
 {
     {
         typedef std::multiset<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::multiset<MoveOnly, std::less<MoveOnly>, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::multiset<MoveOnly, std::less<MoveOnly>, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::multiset<MoveOnly, some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for comp
     typedef std::multiset<MoveOnly, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for comp
     typedef std::multiset<MoveOnly, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for comp
     typedef std::multiset<MoveOnly, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for comp
     typedef std::multiset<MoveOnly, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for comp
     typedef std::multiset<MoveOnly, some_comp2<MoveOnly>, some_alloc3<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp
index 0eb7d871b8b4..b3edd31f749b 100644
--- a/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.special/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <set>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -95,51 +96,42 @@ int main()
 {
     {
         typedef std::set<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::set<MoveOnly, std::less<MoveOnly>, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::set<MoveOnly, std::less<MoveOnly>, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::set<MoveOnly, some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for comp
     typedef std::set<MoveOnly, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for comp
     typedef std::set<MoveOnly, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for comp
     typedef std::set<MoveOnly, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for comp
     typedef std::set<MoveOnly, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for comp
     typedef std::set<MoveOnly, some_comp2<MoveOnly>, some_alloc3<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 
diff --git a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp
index bfff607590fe..845ca758769d 100644
--- a/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/priority.queue/priqueue.special/swap_noexcept.pass.cpp
@@ -18,6 +18,7 @@
 // UNSUPPORTED: c++98, c++03
 
 #include <queue>
+#include <utility>
 #include <cassert>
 
 #include "MoveOnly.h"
@@ -26,7 +27,6 @@ int main()
 {
     {
         typedef std::priority_queue<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 }
diff --git a/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp
index e18f80a91198..542b4901173c 100644
--- a/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/queue/queue.special/swap_noexcept.pass.cpp
@@ -17,6 +17,7 @@
 // UNSUPPORTED: c++98, c++03
 
 #include <queue>
+#include <utility>
 #include <cassert>
 
 #include "MoveOnly.h"
@@ -25,7 +26,6 @@ int main()
 {
     {
         typedef std::queue<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 }
diff --git a/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp
index 976e362a0483..12150055394e 100644
--- a/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/container.adaptors/stack/stack.special/swap_noexcept.pass.cpp
@@ -17,6 +17,7 @@
 // UNSUPPORTED: c++98, c++03
 
 #include <stack>
+#include <utility>
 #include <cassert>
 
 #include "MoveOnly.h"
@@ -25,7 +26,6 @@ int main()
 {
     {
         typedef std::stack<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp
index 2f999e9a7a5d..c0af762fb277 100644
--- a/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.special/swap_noexcept.pass.cpp
@@ -21,6 +21,7 @@
 // This tests a conforming extension
 
 #include <deque>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -56,35 +57,30 @@ int main()
 {
     {
         typedef std::deque<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::deque<MoveOnly, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::deque<MoveOnly, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::deque<MoveOnly, some_alloc<MoveOnly>> C;
-        C c1, c2;
 #if TEST_STD_VER >= 14
     //  In c++14, if POCS is set, swapping the allocator is required not to throw
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #else
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #endif
     }
 #if TEST_STD_VER >= 14
     {
         typedef std::deque<MoveOnly, some_alloc2<MoveOnly>> C;
-        C c1, c2;
     //  if the allocators are always equal, then the swap can be noexcept
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp
index 5f8cf95aa737..c63194f7ee64 100644
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/swap_noexcept.pass.cpp
@@ -21,6 +21,7 @@
 // This tests a conforming extension
 
 #include <forward_list>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -56,35 +57,30 @@ int main()
 {
     {
         typedef std::forward_list<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::forward_list<MoveOnly, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::forward_list<MoveOnly, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::forward_list<MoveOnly, some_alloc<MoveOnly>> C;
-        C c1, c2;
 #if TEST_STD_VER >= 14
     //  In c++14, if POCS is set, swapping the allocator is required not to throw
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #else
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #endif
     }
 #if TEST_STD_VER >= 14
     {
         typedef std::forward_list<MoveOnly, some_alloc2<MoveOnly>> C;
-        C c1, c2;
     //  if the allocators are always equal, then the swap can be noexcept
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp
index 820da4c78f81..512635359c5d 100644
--- a/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp
@@ -21,6 +21,7 @@
 // This tests a conforming extension
 
 #include <list>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -56,35 +57,30 @@ int main()
 {
     {
         typedef std::list<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::list<MoveOnly, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::list<MoveOnly, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::list<MoveOnly, some_alloc<MoveOnly>> C;
-        C c1, c2;
 #if TEST_STD_VER >= 14
     //  In c++14, if POCS is set, swapping the allocator is required not to throw
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #else
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #endif
     }
 #if TEST_STD_VER >= 14
     {
         typedef std::list<MoveOnly, some_alloc2<MoveOnly>> C;
-        C c1, c2;
     //  if the allocators are always equal, then the swap can be noexcept
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 
diff --git a/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp
index 7ba44453b371..1b68eda2757b 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <vector>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -56,35 +57,30 @@ int main()
 {
     {
         typedef std::vector<bool> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::vector<bool, test_allocator<bool>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::vector<bool, other_allocator<bool>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::vector<bool, some_alloc<bool>> C;
-        C c1, c2;
 #if TEST_STD_VER >= 14
     //  In c++14, if POCS is set, swapping the allocator is required not to throw
-        static_assert( noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #else
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #endif
     }
 #if TEST_STD_VER >= 14
     {
         typedef std::vector<bool, some_alloc2<bool>> C;
-        C c1, c2;
     //  if the allocators are always equal, then the swap can be noexcept
-        static_assert( noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp b/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp
index 89fa301ad9bd..214f9a577571 100644
--- a/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <vector>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -57,35 +58,30 @@ int main()
 {
     {
         typedef std::vector<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::vector<MoveOnly, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::vector<MoveOnly, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::vector<MoveOnly, some_alloc<MoveOnly>> C;
-        C c1, c2;
 #if TEST_STD_VER >= 14
     //  In c++14, if POCS is set, swapping the allocator is required not to throw
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #else
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #endif
     }
 #if TEST_STD_VER >= 14
     {
         typedef std::vector<MoveOnly, some_alloc2<MoveOnly>> C;
-        C c1, c2;
     //  if the allocators are always equal, then the swap can be noexcept
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp
index f8f17ffec57a..fc286ceec8eb 100644
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.swap/swap_noexcept.pass.cpp
@@ -26,6 +26,7 @@
 // This tests a conforming extension
 
 #include <unordered_map>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -122,79 +123,65 @@ int main()
 	typedef std::pair<const MoveOnly, MoveOnly> MapType;
     {
         typedef std::unordered_map<MoveOnly, MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_map<MoveOnly, MoveOnly, std::hash<MoveOnly>,
                            std::equal_to<MoveOnly>, test_allocator<MapType>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_map<MoveOnly, MoveOnly, std::hash<MoveOnly>,
                           std::equal_to<MoveOnly>, other_allocator<MapType>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_map<MoveOnly, MoveOnly, some_hash<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_map<MoveOnly, MoveOnly, std::hash<MoveOnly>,
                                                          some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc <MapType>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MapType>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MapType>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MapType>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc <MapType>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MapType>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MapType>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MapType>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_map<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc3<MapType>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp
index 553131182315..7a58709c9fc9 100644
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_noexcept.pass.cpp
@@ -26,6 +26,7 @@
 // This tests a conforming extension
 
 #include <unordered_map>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -121,78 +122,64 @@ int main()
     typedef std::pair<const MoveOnly, MoveOnly> V;
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly, std::hash<MoveOnly>,
                            std::equal_to<MoveOnly>, test_allocator<V>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly, std::hash<MoveOnly>,
                           std::equal_to<MoveOnly>, other_allocator<V>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multimap<MoveOnly, MoveOnly, std::hash<MoveOnly>,
                                                          some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc <V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // NOT always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_multimap<MoveOnly, MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc3<V>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp
index df9f18b147e3..c221b6f2edb0 100644
--- a/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/unord.multiset.swap/swap_noexcept.pass.cpp
@@ -26,6 +26,7 @@
 // This tests a conforming extension
 
 #include <unordered_set>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -122,79 +123,65 @@ int main()
 {
     {
         typedef std::unordered_multiset<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multiset<MoveOnly, std::hash<MoveOnly>,
                            std::equal_to<MoveOnly>, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multiset<MoveOnly, std::hash<MoveOnly>,
                           std::equal_to<MoveOnly>, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multiset<MoveOnly, some_hash<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_multiset<MoveOnly, std::hash<MoveOnly>,
                                                          some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_multiset<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc3<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp
index d35d79b31266..4a16ddd3f4ce 100644
--- a/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/unord.set.swap/swap_noexcept.pass.cpp
@@ -26,6 +26,7 @@
 // This tests a conforming extension
 
 #include <unordered_set>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -122,79 +123,65 @@ int main()
 {
     {
         typedef std::unordered_set<MoveOnly> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_set<MoveOnly, std::hash<MoveOnly>,
                            std::equal_to<MoveOnly>, test_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_set<MoveOnly, std::hash<MoveOnly>,
                           std::equal_to<MoveOnly>, other_allocator<MoveOnly>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::unordered_set<MoveOnly, std::hash<MoveOnly>,
                                                          some_comp<MoveOnly>> C;
-        C c1, c2;
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
 #if TEST_STD_VER >= 14
     { // POCS allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, throwable swap for comp
     typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, throwable swap for hash, nothrow swap for comp
     typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, throwable swap for comp
     typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert(!noexcept(swap(c1, c2)), "");
+    static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // POCS allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     { // always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 
     { // NOT always equal allocator, nothrow swap for hash, nothrow swap for comp
     typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc3<MoveOnly>> C;
-    C c1, c2;
-    static_assert( noexcept(swap(c1, c2)), "");
+    LIBCPP_STATIC_ASSERT( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }
diff --git a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp
index 4ac13d10e670..757d5eeb2dc3 100644
--- a/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.nonmembers/string.special/swap_noexcept.pass.cpp
@@ -22,6 +22,7 @@
 // This tests a conforming extension
 
 #include <string>
+#include <utility>
 #include <cassert>
 
 #include "test_macros.h"
@@ -56,30 +57,26 @@ int main()
 {
     {
         typedef std::string C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::basic_string<char, std::char_traits<char>, test_allocator<char>> C;
-        C c1, c2;
-        static_assert(noexcept(swap(c1, c2)), "");
+        LIBCPP_STATIC_ASSERT(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
     {
         typedef std::basic_string<char, std::char_traits<char>, some_alloc<char>> C;
-        C c1, c2;
 #if TEST_STD_VER >= 14
     //  In c++14, if POCS is set, swapping the allocator is required not to throw
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #else
-        static_assert(!noexcept(swap(c1, c2)), "");
+        static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
 #endif
     }
 #if TEST_STD_VER >= 14
     {
         typedef std::basic_string<char, std::char_traits<char>, some_alloc2<char>> C;
-        C c1, c2;
     //  if the allocators are always equal, then the swap can be noexcept
-        static_assert( noexcept(swap(c1, c2)), "");
+        static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
     }
 #endif
 }