diff --git a/libcxx/include/__algorithm/stable_sort.h b/libcxx/include/__algorithm/stable_sort.h
--- a/libcxx/include/__algorithm/stable_sort.h
+++ b/libcxx/include/__algorithm/stable_sort.h
@@ -38,14 +38,14 @@
     {
         if (__first1 == __last1)
         {
-            for (; __first2 != __last2; ++__first2, ++__result, (void)__d.template __incr<value_type>())
+            for (; __first2 != __last2; ++__first2, (void) ++__result, __d.template __incr<value_type>())
                 ::new ((void*)__result) value_type(_VSTD::move(*__first2));
             __h.release();
             return;
         }
         if (__first2 == __last2)
         {
-            for (; __first1 != __last1; ++__first1, ++__result, (void)__d.template __incr<value_type>())
+            for (; __first1 != __last1; ++__first1, (void) ++__result, __d.template __incr<value_type>())
                 ::new ((void*)__result) value_type(_VSTD::move(*__first1));
             __h.release();
             return;
diff --git a/libcxx/include/__hash_table b/libcxx/include/__hash_table
--- a/libcxx/include/__hash_table
+++ b/libcxx/include/__hash_table
@@ -2348,7 +2348,7 @@
             size_type __chash = __constrain_hash(__cp->__hash(), __nbc);
             __bucket_list_[__chash] = __pp;
             size_type __phash = __chash;
-            for (__pp = __cp, __cp = __cp->__next_; __cp != nullptr;
+            for (__pp = __cp, void(), __cp = __cp->__next_; __cp != nullptr;
                                                            __cp = __pp->__next_)
             {
                 __chash = __constrain_hash(__cp->__hash(), __nbc);
@@ -2758,7 +2758,7 @@
     {
         for (__np = __np->__next_; __np != nullptr &&
                                    __constrain_hash(__np->__hash(), __bc) == __n;
-                                                    __np = __np->__next_, ++__r)
+                                                    __np = __np->__next_, (void) ++__r)
             ;
     }
     return __r;
diff --git a/libcxx/include/__memory/uninitialized_algorithms.h b/libcxx/include/__memory/uninitialized_algorithms.h
--- a/libcxx/include/__memory/uninitialized_algorithms.h
+++ b/libcxx/include/__memory/uninitialized_algorithms.h
@@ -145,7 +145,7 @@
 #ifndef _LIBCPP_NO_EXCEPTIONS
     try {
 #endif
-    for (; __n > 0; (void)++__idx, --__n)
+    for (; __n > 0; ++__idx, (void) --__n)
         ::new ((void*)_VSTD::addressof(*__idx)) _Vt;
     return __idx;
 #ifndef _LIBCPP_NO_EXCEPTIONS
@@ -183,7 +183,7 @@
 #ifndef _LIBCPP_NO_EXCEPTIONS
     try {
 #endif
-    for (; __n > 0; (void)++__idx, --__n)
+    for (; __n > 0; ++__idx, (void) --__n)
         ::new ((void*)_VSTD::addressof(*__idx)) _Vt();
     return __idx;
 #ifndef _LIBCPP_NO_EXCEPTIONS
@@ -203,7 +203,7 @@
 #ifndef _LIBCPP_NO_EXCEPTIONS
     try {
 #endif
-    for (; __first != __last; (void)++__idx, ++__first)
+    for (; __first != __last; ++__idx, (void) ++__first)
         ::new ((void*)_VSTD::addressof(*__idx)) _Vt(_VSTD::move(*__first));
     return __idx;
 #ifndef _LIBCPP_NO_EXCEPTIONS
@@ -223,7 +223,7 @@
 #ifndef _LIBCPP_NO_EXCEPTIONS
     try {
 #endif
-    for (; __n > 0; ++__idx, (void)++__first, --__n)
+    for (; __n > 0; ++__idx, (void) ++__first, --__n)
         ::new ((void*)_VSTD::addressof(*__idx)) _Vt(_VSTD::move(*__first));
     return {__first, __idx};
 #ifndef _LIBCPP_NO_EXCEPTIONS
diff --git a/libcxx/include/__split_buffer b/libcxx/include/__split_buffer
--- a/libcxx/include/__split_buffer
+++ b/libcxx/include/__split_buffer
@@ -239,7 +239,7 @@
             size_type __old_cap = __end_cap() - __first_;
             size_type __new_cap = _VSTD::max<size_type>(2 * __old_cap, 8);
             __split_buffer __buf(__new_cap, 0, __a);
-            for (pointer __p = __begin_; __p != __end_; ++__p, ++__buf.__end_)
+            for (pointer __p = __begin_; __p != __end_; ++__p, (void) ++__buf.__end_)
                 __alloc_traits::construct(__buf.__alloc(),
                         _VSTD::__to_address(__buf.__end_), _VSTD::move(*__p));
             swap(__buf);
@@ -259,7 +259,7 @@
 __split_buffer<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last)
 {
     _ConstructTransaction __tx(&this->__end_, _VSTD::distance(__first, __last));
-    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, ++__first) {
+    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, (void) ++__first) {
         __alloc_traits::construct(this->__alloc(),
             _VSTD::__to_address(__tx.__pos_), *__first);
     }
diff --git a/libcxx/include/deque b/libcxx/include/deque
--- a/libcxx/include/deque
+++ b/libcxx/include/deque
@@ -2214,7 +2214,7 @@
         size_type __de = __base::size() - __pos;
         if (__n > __de)
         {
-            for (size_type __m = __n - __de; __m; --__m, ++__i, ++__base::size())
+            for (size_type __m = __n - __de; __m; --__m, (void) ++__i, ++__base::size())
                 __alloc_traits::construct(__a, _VSTD::addressof(*__i), __v);
             __n = __de;
         }
@@ -2317,7 +2317,7 @@
         if (__n > 0)
         {
             iterator __oen = __old_end - __n;
-            for (iterator __j = __oen; __j != __old_end; ++__i, ++__j, ++__base::size())
+            for (iterator __j = __oen; __j != __old_end; ++__i, (void) ++__j, ++__base::size())
                 __alloc_traits::construct(__a, _VSTD::addressof(*__i), _VSTD::move(*__j));
             if (__n < __de)
                 __old_end = _VSTD::move_backward(__old_end - __de, __oen, __old_end);
diff --git a/libcxx/include/list b/libcxx/include/list
--- a/libcxx/include/list
+++ b/libcxx/include/list
@@ -1408,7 +1408,7 @@
 {
     iterator __i = begin();
     iterator __e = end();
-    for (; __f != __l && __i != __e; ++__f, ++__i)
+    for (; __f != __l && __i != __e; ++__f, (void) ++__i)
         *__i = *__f;
     if (__i == __e)
         insert(__e, __f, __l);
@@ -1425,7 +1425,7 @@
 {
     iterator __i = begin();
     iterator __e = end();
-    for (; __n > 0 && __i != __e; --__n, ++__i)
+    for (; __n > 0 && __i != __e; --__n, (void) ++__i)
         *__i = __x;
     if (__i == __e)
         insert(__e, __n, __x);
@@ -1495,7 +1495,7 @@
         try
         {
 #endif // _LIBCPP_NO_EXCEPTIONS
-            for (--__n; __n != 0; --__n, ++__e, ++__ds)
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
             {
                 __hold.reset(__node_alloc_traits::allocate(__na, 1));
                 __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
@@ -1561,7 +1561,7 @@
         try
         {
 #endif // _LIBCPP_NO_EXCEPTIONS
-            for (++__f; __f != __l; ++__f, (void) ++__e, (void) ++__ds)
+            for (++__f; __f != __l; ++__f, (void) ++__e, ++__ds)
             {
                 __hold.reset(__node_alloc_traits::allocate(__na, 1));
                 __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
@@ -1909,7 +1909,7 @@
         try
         {
 #endif // _LIBCPP_NO_EXCEPTIONS
-            for (--__n; __n != 0; --__n, ++__e, ++__ds)
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
             {
                 __hold.reset(__node_alloc_traits::allocate(__na, 1));
                 __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
@@ -1967,7 +1967,7 @@
         try
         {
 #endif // _LIBCPP_NO_EXCEPTIONS
-            for (--__n; __n != 0; --__n, ++__e, ++__ds)
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
             {
                 __hold.reset(__node_alloc_traits::allocate(__na, 1));
                 __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
@@ -2244,7 +2244,7 @@
             {
                 size_type __ds = 1;
                 iterator __m2 = _VSTD::next(__f2);
-                for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, ++__ds)
+                for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, (void) ++__ds)
                     ;
                 base::__sz() += __ds;
                 __c.__sz() -= __ds;
diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -2525,7 +2525,7 @@
             __grow_by(__cap, __n - __cap, __sz, 0, __sz);
         }
         pointer __p = __get_pointer();
-        for (; __first != __last; ++__first, ++__p)
+        for (; __first != __last; ++__p, (void) ++__first)
             traits_type::assign(*__p, *__first);
         traits_type::assign(*__p, value_type());
         __set_size(__n);
@@ -2703,7 +2703,7 @@
             if (__cap - __sz < __n)
                 __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
             pointer __p = __get_pointer() + __sz;
-            for (; __first != __last; ++__p, ++__first)
+            for (; __first != __last; ++__p, (void) ++__first)
                 traits_type::assign(*__p, *__first);
             traits_type::assign(*__p, value_type());
             __set_size(__sz + __n);
@@ -2881,7 +2881,7 @@
             __sz += __n;
             __set_size(__sz);
             traits_type::assign(__p[__sz], value_type());
-            for (__p += __ip; __first != __last; ++__p, ++__first)
+            for (__p += __ip; __first != __last; ++__p, (void) ++__first)
                 traits_type::assign(*__p, *__first);
         }
         else
diff --git a/libcxx/include/vector b/libcxx/include/vector
--- a/libcxx/include/vector
+++ b/libcxx/include/vector
@@ -1063,7 +1063,7 @@
 {
     _ConstructTransaction __tx(*this, __n);
     const_pointer __new_end = __tx.__new_end_;
-    for (pointer __pos = __tx.__pos_; __pos != __new_end; ++__pos, __tx.__pos_ = __pos) {
+    for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
         __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__pos));
     }
 }
@@ -1081,7 +1081,7 @@
 {
     _ConstructTransaction __tx(*this, __n);
     const_pointer __new_end = __tx.__new_end_;
-    for (pointer __pos = __tx.__pos_; __pos != __new_end; ++__pos, __tx.__pos_ = __pos) {
+    for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
         __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__pos), __x);
     }
 }
@@ -1775,7 +1775,7 @@
       pointer __i = __from_s + __n;
       _ConstructTransaction __tx(*this, __from_e - __i);
       for (pointer __pos = __tx.__pos_; __i < __from_e;
-           ++__i, ++__pos, __tx.__pos_ = __pos) {
+           ++__i, (void) ++__pos, __tx.__pos_ = __pos) {
           __alloc_traits::construct(this->__alloc(),
                                     _VSTD::__to_address(__pos),
                                     _VSTD::move(*__i));
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_iter_iter.pass.cpp
@@ -246,7 +246,7 @@
         c.insert(c.end(), std::move_iterator<I>(&mo), std::move_iterator<I>(&mo+1));
     }
     int j = 0;
-    for (CI i = c.begin(); i != c.end(); ++i, ++j)
+    for (CI i = c.begin(); i != c.end(); ++i, (void) ++j)
         assert(*i == MoveOnly(j));
     {
         MoveOnly mo(1);
@@ -254,7 +254,7 @@
         c.insert(c.end(), std::move_iterator<I>(I(&mo)), std::move_iterator<I>(I(&mo+1)));
     }
     j = 0;
-    for (CI i = c.begin(); i != c.end(); ++i, ++j)
+    for (CI i = c.begin(); i != c.end(); ++i, (void) ++j)
         assert(*i == MoveOnly(j));
 #endif
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/insert_rvalue.pass.cpp
@@ -54,11 +54,11 @@
     assert(c1.size() == c1_osize + 1);
     assert(static_cast<std::size_t>(distance(c1.begin(), c1.end())) == c1.size());
     i = c1.begin();
-    for (int j = 0; j < P; ++j, ++i)
+    for (int j = 0; j < P; ++j, (void) ++i)
         assert(*i == MoveOnly(j));
     assert(*i == MoveOnly(x));
     ++i;
-    for (int j = P; static_cast<std::size_t>(j) < c1_osize; ++j, ++i)
+    for (int j = P; static_cast<std::size_t>(j) < c1_osize; ++j, (void) ++i)
         assert(*i == MoveOnly(j));
 }
 
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_back_rvalue.pass.cpp
@@ -53,7 +53,7 @@
     {
         C c = make<C>(size, rng[j]);
         typename C::const_iterator it = c.begin();
-        for (int i = 0; i < size; ++i, ++it)
+        for (int i = 0; i < size; ++i, (void) ++it)
             assert(*it == MoveOnly(i));
     }
 }
diff --git a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp
--- a/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/deque.modifiers/push_front_rvalue.pass.cpp
@@ -55,7 +55,7 @@
     I i = c1.begin();
     assert(*i == MoveOnly(x));
     ++i;
-    for (int j = 0; static_cast<std::size_t>(j) < c1_osize; ++j, ++i)
+    for (int j = 0; static_cast<std::size_t>(j) < c1_osize; ++j, (void) ++i)
         assert(*i == MoveOnly(j));
 }
 
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/assign_move.pass.cpp
@@ -34,7 +34,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(10));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == n);
         assert(n == 10);
         assert(c1.get_allocator() == A(10));
@@ -51,7 +51,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(11));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == n);
         assert(n == 10);
         assert(c1.get_allocator() == A(11));
@@ -68,7 +68,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(10));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == 10+n);
         assert(n == 4);
         assert(c1.get_allocator() == A(10));
@@ -85,7 +85,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(11));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == 10+n);
         assert(n == 4);
         assert(c1.get_allocator() == A(11));
@@ -103,7 +103,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(10));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == n);
         assert(n == 10);
         assert(c1.get_allocator() == A(10));
@@ -120,7 +120,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(11));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == n);
         assert(n == 10);
         assert(c1.get_allocator() == A(10));
@@ -137,7 +137,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(10));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == 10+n);
         assert(n == 4);
         assert(c1.get_allocator() == A(10));
@@ -154,7 +154,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A(11));
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == 10+n);
         assert(n == 4);
         assert(c1.get_allocator() == A(10));
@@ -171,7 +171,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A());
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == n);
         assert(n == 10);
         assert(c1.get_allocator() == A());
@@ -188,7 +188,7 @@
         C c1(I(std::begin(t1)), I(std::end(t1)), A());
         c1 = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, ++n)
+        for (C::const_iterator i = c1.cbegin(); i != c1.cend(); ++i, (void) ++n)
             assert(*i == 10+n);
         assert(n == 4);
         assert(c1.get_allocator() == A());
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move.pass.cpp
@@ -32,7 +32,7 @@
         C c0(I(std::begin(t)), I(std::end(t)), A(10));
         C c = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, ++n)
+        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, (void) ++n)
             assert(*i == n);
         assert(n == std::end(t) - std::begin(t));
         assert(c0.empty());
@@ -47,7 +47,7 @@
         C c0(I(std::begin(t)), I(std::end(t)), A(10));
         C c = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, ++n)
+        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, (void) ++n)
             assert(*i == n);
         assert(n == std::end(t) - std::begin(t));
         assert(c0.empty());
@@ -62,7 +62,7 @@
         C c0(I(std::begin(t)), I(std::end(t)), A());
         C c = std::move(c0);
         int n = 0;
-        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, ++n)
+        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, (void) ++n)
             assert(*i == n);
         assert(n == std::end(t) - std::begin(t));
         assert(c0.empty());
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.cons/move_alloc.pass.cpp
@@ -32,7 +32,7 @@
         C c0(I(std::begin(t)), I(std::end(t)), A(10));
         C c(std::move(c0), A(10));
         unsigned n = 0;
-        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, ++n)
+        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, (void) ++n)
             assert(*i == n);
         assert(n == static_cast<unsigned>(std::end(t) - std::begin(t)));
         assert(c0.empty());
@@ -47,7 +47,7 @@
         C c0(I(std::begin(t)), I(std::end(t)), A(10));
         C c(std::move(c0), A(9));
         unsigned n = 0;
-        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, ++n)
+        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, (void) ++n)
             assert(*i == n);
         assert(n == static_cast<unsigned>(std::end(t) - std::begin(t)));
         assert(!c0.empty());
@@ -62,7 +62,7 @@
         C c0(I(std::begin(t)), I(std::end(t)), A());
         C c(std::move(c0), A());
         unsigned n = 0;
-        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, ++n)
+        for (C::const_iterator i = c.begin(), e = c.end(); i != e; ++i, (void) ++n)
             assert(*i == n);
         assert(n == static_cast<unsigned>(std::end(t) - std::begin(t)));
         assert(c0.empty());
diff --git a/libcxx/test/support/MoveOnly.h b/libcxx/test/support/MoveOnly.h
--- a/libcxx/test/support/MoveOnly.h
+++ b/libcxx/test/support/MoveOnly.h
@@ -48,6 +48,9 @@
         { return MoveOnly{data_ + x.data_}; }
     TEST_CONSTEXPR_CXX14 MoveOnly operator*(const MoveOnly& x) const
         { return MoveOnly{data_ * x.data_}; }
+
+    template<class T, class U>
+    friend void operator,(T t, U u) = delete;
 };
 
 namespace std {