Index: test/std/depr/depr.c.headers/inttypes_h.pass.cpp
===================================================================
--- test/std/depr/depr.c.headers/inttypes_h.pass.cpp
+++ test/std/depr/depr.c.headers/inttypes_h.pass.cpp
@@ -872,54 +872,56 @@
 #error SCNxPTR not defined
 #endif
 
+template <class T> void test()
+{
+    T t = 0;
+    ((void)t); // Prevent unused warning
+}
+
 int main()
 {
-    {
-    int8_t  i1 = 0;
-    int16_t i2 = 0;
-    int32_t i3 = 0;
-    int64_t i4 = 0;
-    }
-    {
-    uint8_t  i1 = 0;
-    uint16_t i2 = 0;
-    uint32_t i3 = 0;
-    uint64_t i4 = 0;
-    }
-    {
-    int_least8_t  i1 = 0;
-    int_least16_t i2 = 0;
-    int_least32_t i3 = 0;
-    int_least64_t i4 = 0;
-    }
-    {
-    uint_least8_t  i1 = 0;
-    uint_least16_t i2 = 0;
-    uint_least32_t i3 = 0;
-    uint_least64_t i4 = 0;
-    }
-    {
-    int_fast8_t  i1 = 0;
-    int_fast16_t i2 = 0;
-    int_fast32_t i3 = 0;
-    int_fast64_t i4 = 0;
-    }
-    {
-    uint_fast8_t  i1 = 0;
-    uint_fast16_t i2 = 0;
-    uint_fast32_t i3 = 0;
-    uint_fast64_t i4 = 0;
-    }
-    {
-    intptr_t  i1 = 0;
-    uintptr_t i2 = 0;
-    intmax_t  i3 = 0;
-    uintmax_t i4 = 0;
-    }
+    test<int8_t >();
+    test<int16_t>();
+    test<int32_t>();
+    test<int64_t>();
+
+    test<uint8_t >();
+    test<uint16_t>();
+    test<uint32_t>();
+    test<uint64_t>();
+
+    test<int_least8_t >();
+    test<int_least16_t>();
+    test<int_least32_t>();
+    test<int_least64_t>();
+
+    test<uint_least8_t >();
+    test<uint_least16_t>();
+    test<uint_least32_t>();
+    test<uint_least64_t>();
+
+    test<int_fast8_t >();
+    test<int_fast16_t>();
+    test<int_fast32_t>();
+    test<int_fast64_t>();
+
+    test<uint_fast8_t >();
+    test<uint_fast16_t>();
+    test<uint_fast32_t>();
+    test<uint_fast64_t>();
+
+    test<intptr_t >();
+    test<uintptr_t>();
+    test<intmax_t >();
+    test<uintmax_t>();
+
     {
     imaxdiv_t  i1 = {};
+    ((void)i1); // Prevent unused warning
     }
+
     intmax_t i = 0;
+    ((void)i); // Prevent unused warning
     static_assert((std::is_same<decltype(imaxabs(i)), intmax_t>::value), "");
     static_assert((std::is_same<decltype(imaxdiv(i, i)), imaxdiv_t>::value), "");
     static_assert((std::is_same<decltype(strtoimax("", (char**)0, 0)), intmax_t>::value), "");
Index: test/std/input.output/file.streams/c.files/cinttypes.pass.cpp
===================================================================
--- test/std/input.output/file.streams/c.files/cinttypes.pass.cpp
+++ test/std/input.output/file.streams/c.files/cinttypes.pass.cpp
@@ -872,54 +872,56 @@
 #error SCNxPTR not defined
 #endif
 
+template <class T> void test()
+{
+    T t = 0;
+    ((void)t); // Prevent unused warning
+}
+
 int main()
 {
-    {
-    std::int8_t  i1 = 0;
-    std::int16_t i2 = 0;
-    std::int32_t i3 = 0;
-    std::int64_t i4 = 0;
-    }
-    {
-    std::uint8_t  i1 = 0;
-    std::uint16_t i2 = 0;
-    std::uint32_t i3 = 0;
-    std::uint64_t i4 = 0;
-    }
-    {
-    std::int_least8_t  i1 = 0;
-    std::int_least16_t i2 = 0;
-    std::int_least32_t i3 = 0;
-    std::int_least64_t i4 = 0;
-    }
-    {
-    std::uint_least8_t  i1 = 0;
-    std::uint_least16_t i2 = 0;
-    std::uint_least32_t i3 = 0;
-    std::uint_least64_t i4 = 0;
-    }
-    {
-    std::int_fast8_t  i1 = 0;
-    std::int_fast16_t i2 = 0;
-    std::int_fast32_t i3 = 0;
-    std::int_fast64_t i4 = 0;
-    }
-    {
-    std::uint_fast8_t  i1 = 0;
-    std::uint_fast16_t i2 = 0;
-    std::uint_fast32_t i3 = 0;
-    std::uint_fast64_t i4 = 0;
-    }
-    {
-    std::intptr_t  i1 = 0;
-    std::uintptr_t i2 = 0;
-    std::intmax_t  i3 = 0;
-    std::uintmax_t i4 = 0;
-    }
+    test<std::int8_t >();
+    test<std::int16_t>();
+    test<std::int32_t>();
+    test<std::int64_t>();
+
+    test<std::uint8_t >();
+    test<std::uint16_t>();
+    test<std::uint32_t>();
+    test<std::uint64_t>();
+
+    test<std::int_least8_t >();
+    test<std::int_least16_t>();
+    test<std::int_least32_t>();
+    test<std::int_least64_t>();
+
+    test<std::uint_least8_t >();
+    test<std::uint_least16_t>();
+    test<std::uint_least32_t>();
+    test<std::uint_least64_t>();
+
+    test<std::int_fast8_t >();
+    test<std::int_fast16_t>();
+    test<std::int_fast32_t>();
+    test<std::int_fast64_t>();
+
+    test<std::uint_fast8_t >();
+    test<std::uint_fast16_t>();
+    test<std::uint_fast32_t>();
+    test<std::uint_fast64_t>();
+
+    test<std::intptr_t >();
+    test<std::uintptr_t>();
+    test<std::intmax_t >();
+    test<std::uintmax_t>();
+
     {
     std::imaxdiv_t  i1 = {};
+    ((void)i1); // Prevent unused warning
     }
+
     std::intmax_t i = 0;
+    ((void)i); // Prevent unused warning
     static_assert((std::is_same<decltype(std::imaxabs(i)), std::intmax_t>::value), "");
     static_assert((std::is_same<decltype(std::imaxdiv(i, i)), std::imaxdiv_t>::value), "");
     static_assert((std::is_same<decltype(std::strtoimax("", (char**)0, 0)), std::intmax_t>::value), "");
Index: test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp
===================================================================
--- test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp
+++ test/std/input.output/iostream.format/quoted.manip/quoted.pass.cpp
@@ -32,6 +32,7 @@
 
     std::basic_stringstream<CharT, Traits> ss;
     bool skippingws = is_skipws ( ss );
+    ((void)skippingws); // Prevent unused warning
     ss << q;
     ss >> q;
     }
Index: test/std/input.output/iostream.forward/iosfwd.pass.cpp
===================================================================
--- test/std/input.output/iostream.forward/iosfwd.pass.cpp
+++ test/std/input.output/iostream.forward/iosfwd.pass.cpp
@@ -12,131 +12,112 @@
 #include <iosfwd>
 #include <cwchar>  // for mbstate_t
 
+template <class Ptr> void test()
+{
+    Ptr p = 0;
+    ((void)p); // Prevent unused warning
+}
+
 int main()
 {
-    {
-    std::char_traits<char>*               t1 = 0;
-    std::char_traits<wchar_t>*            t2 = 0;
-    std::char_traits<unsigned short>*     t3 = 0;
-    }
-    {
-    std::basic_ios<char>*                 t1 = 0;
-    std::basic_ios<wchar_t>*              t2 = 0;
-    std::basic_ios<unsigned short>*       t3 = 0;
-    }
-    {
-    std::basic_streambuf<char>*           t1 = 0;
-    std::basic_streambuf<wchar_t>*        t2 = 0;
-    std::basic_streambuf<unsigned short>* t3 = 0;
-    }
-    {
-    std::basic_istream<char>*             t1 = 0;
-    std::basic_istream<wchar_t>*          t2 = 0;
-    std::basic_istream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_ostream<char>*             t1 = 0;
-    std::basic_ostream<wchar_t>*          t2 = 0;
-    std::basic_ostream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_iostream<char>*             t1 = 0;
-    std::basic_iostream<wchar_t>*          t2 = 0;
-    std::basic_iostream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_stringbuf<char>*             t1 = 0;
-    std::basic_stringbuf<wchar_t>*          t2 = 0;
-    std::basic_stringbuf<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_istringstream<char>*             t1 = 0;
-    std::basic_istringstream<wchar_t>*          t2 = 0;
-    std::basic_istringstream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_ostringstream<char>*             t1 = 0;
-    std::basic_ostringstream<wchar_t>*          t2 = 0;
-    std::basic_ostringstream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_stringstream<char>*             t1 = 0;
-    std::basic_stringstream<wchar_t>*          t2 = 0;
-    std::basic_stringstream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_filebuf<char>*             t1 = 0;
-    std::basic_filebuf<wchar_t>*          t2 = 0;
-    std::basic_filebuf<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_ifstream<char>*             t1 = 0;
-    std::basic_ifstream<wchar_t>*          t2 = 0;
-    std::basic_ifstream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_ofstream<char>*             t1 = 0;
-    std::basic_ofstream<wchar_t>*          t2 = 0;
-    std::basic_ofstream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::basic_fstream<char>*             t1 = 0;
-    std::basic_fstream<wchar_t>*          t2 = 0;
-    std::basic_fstream<unsigned short>*   t3 = 0;
-    }
-    {
-    std::istreambuf_iterator<char>*             t1 = 0;
-    std::istreambuf_iterator<wchar_t>*          t2 = 0;
-    std::istreambuf_iterator<unsigned short>*   t3 = 0;
-    }
-    {
-    std::ostreambuf_iterator<char>*             t1 = 0;
-    std::ostreambuf_iterator<wchar_t>*          t2 = 0;
-    std::ostreambuf_iterator<unsigned short>*   t3 = 0;
-    }
-    {
-    std::ios*           t1 = 0;
-    std::wios*          t2 = 0;
-    }
-    {
-    std::streambuf*        t1 = 0;
-    std::istream*          t2 = 0;
-    std::ostream*          t3 = 0;
-    std::iostream*         t4 = 0;
-    }
-    {
-    std::stringbuf*            t1 = 0;
-    std::istringstream*        t2 = 0;
-    std::ostringstream*        t3 = 0;
-    std::stringstream*         t4 = 0;
-    }
-    {
-    std::filebuf*         t1 = 0;
-    std::ifstream*        t2 = 0;
-    std::ofstream*        t3 = 0;
-    std::fstream*         t4 = 0;
-    }
-    {
-    std::wstreambuf*        t1 = 0;
-    std::wistream*          t2 = 0;
-    std::wostream*          t3 = 0;
-    std::wiostream*         t4 = 0;
-    }
-    {
-    std::wstringbuf*            t1 = 0;
-    std::wistringstream*        t2 = 0;
-    std::wostringstream*        t3 = 0;
-    std::wstringstream*         t4 = 0;
-    }
-    {
-    std::wfilebuf*         t1 = 0;
-    std::wifstream*        t2 = 0;
-    std::wofstream*        t3 = 0;
-    std::wfstream*         t4 = 0;
-    }
-    {
-    std::fpos<std::mbstate_t>*   t1 = 0;
-    std::streampos*              t2 = 0;
-    std::wstreampos*             t3 = 0;
-    }
+    test<std::char_traits<char>*          >();
+    test<std::char_traits<wchar_t>*       >();
+    test<std::char_traits<unsigned short>*>();
+
+    test<std::basic_ios<char>*          >();
+    test<std::basic_ios<wchar_t>*       >();
+    test<std::basic_ios<unsigned short>*>();
+
+    test<std::basic_streambuf<char>*          >();
+    test<std::basic_streambuf<wchar_t>*       >();
+    test<std::basic_streambuf<unsigned short>*>();
+
+    test<std::basic_istream<char>*          >();
+    test<std::basic_istream<wchar_t>*       >();
+    test<std::basic_istream<unsigned short>*>();
+
+    test<std::basic_ostream<char>*          >();
+    test<std::basic_ostream<wchar_t>*       >();
+    test<std::basic_ostream<unsigned short>*>();
+
+    test<std::basic_iostream<char>*          >();
+    test<std::basic_iostream<wchar_t>*       >();
+    test<std::basic_iostream<unsigned short>*>();
+
+    test<std::basic_stringbuf<char>*          >();
+    test<std::basic_stringbuf<wchar_t>*       >();
+    test<std::basic_stringbuf<unsigned short>*>();
+
+    test<std::basic_istringstream<char>*          >();
+    test<std::basic_istringstream<wchar_t>*       >();
+    test<std::basic_istringstream<unsigned short>*>();
+
+    test<std::basic_ostringstream<char>*          >();
+    test<std::basic_ostringstream<wchar_t>*       >();
+    test<std::basic_ostringstream<unsigned short>*>();
+
+    test<std::basic_stringstream<char>*          >();
+    test<std::basic_stringstream<wchar_t>*       >();
+    test<std::basic_stringstream<unsigned short>*>();
+
+    test<std::basic_filebuf<char>*          >();
+    test<std::basic_filebuf<wchar_t>*       >();
+    test<std::basic_filebuf<unsigned short>*>();
+
+    test<std::basic_ifstream<char>*          >();
+    test<std::basic_ifstream<wchar_t>*       >();
+    test<std::basic_ifstream<unsigned short>*>();
+
+    test<std::basic_ofstream<char>*          >();
+    test<std::basic_ofstream<wchar_t>*       >();
+    test<std::basic_ofstream<unsigned short>*>();
+
+    test<std::basic_fstream<char>*          >();
+    test<std::basic_fstream<wchar_t>*       >();
+    test<std::basic_fstream<unsigned short>*>();
+
+    test<std::istreambuf_iterator<char>*          >();
+    test<std::istreambuf_iterator<wchar_t>*       >();
+    test<std::istreambuf_iterator<unsigned short>*>();
+
+    test<std::ostreambuf_iterator<char>*          >();
+    test<std::ostreambuf_iterator<wchar_t>*       >();
+    test<std::ostreambuf_iterator<unsigned short>*>();
+
+    test<std::ios* >();
+    test<std::wios*>();
+
+    test<std::streambuf*>();
+    test<std::istream*  >();
+    test<std::ostream*  >();
+    test<std::iostream* >();
+
+    test<std::stringbuf*    >();
+    test<std::istringstream*>();
+    test<std::ostringstream*>();
+    test<std::stringstream* >();
+
+    test<std::filebuf* >();
+    test<std::ifstream*>();
+    test<std::ofstream*>();
+    test<std::fstream* >();
+
+    test<std::wstreambuf*>();
+    test<std::wistream*  >();
+    test<std::wostream*  >();
+    test<std::wiostream* >();
+
+    test<std::wstringbuf*    >();
+    test<std::wistringstream*>();
+    test<std::wostringstream*>();
+    test<std::wstringstream* >();
+
+    test<std::wfilebuf* >();
+    test<std::wifstream*>();
+    test<std::wofstream*>();
+    test<std::wfstream* >();
+
+    test<std::fpos<std::mbstate_t>*>();
+    test<std::streampos*           >();
+    test<std::wstreampos*          >();
 }
Index: test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp
+++ test/std/localization/locale.categories/category.collate/locale.collate/types.pass.cpp
@@ -29,6 +29,7 @@
     {
         assert(std::has_facet<std::collate<char> >(l));
         const std::collate<char>& f = std::use_facet<std::collate<char> >(l);
+        ((void)f); // Prevent unused warning
         {
             (void)std::collate<char>::id;
         }
@@ -39,6 +40,7 @@
     {
         assert(std::has_facet<std::collate<wchar_t> >(l));
         const std::collate<wchar_t>& f = std::use_facet<std::collate<wchar_t> >(l);
+        ((void)f); // Prevent unused warning
         {
             (void)std::collate<wchar_t>::id;
         }
Index: test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp
+++ test/std/localization/locale.categories/category.ctype/facet.ctype.special/types.pass.cpp
@@ -28,6 +28,7 @@
     {
         assert(std::has_facet<std::ctype<char> >(l));
         const std::ctype<char>& f = std::use_facet<std::ctype<char> >(l);
+        ((void)f); // Prevent unused warning
         {
             (void)std::ctype<char>::id;
         }
Index: test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp
+++ test/std/localization/locale.categories/category.ctype/locale.codecvt/types_char.pass.cpp
@@ -36,5 +36,6 @@
     std::locale l = std::locale::classic();
     assert(std::has_facet<F>(l));
     const F& f = std::use_facet<F>(l);
+    ((void)f); // Prevent unused warning
     (void)F::id;
 }
Index: test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp
+++ test/std/localization/locale.categories/category.ctype/locale.codecvt/types_wchar_t.pass.cpp
@@ -36,5 +36,6 @@
     std::locale l = std::locale::classic();
     assert(std::has_facet<F>(l));
     const F& f = std::use_facet<F>(l);
+    ((void)f); // Prevent unused warning
     (void)F::id;
 }
Index: test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp
+++ test/std/localization/locale.categories/category.ctype/locale.ctype/types.pass.cpp
@@ -28,6 +28,7 @@
     {
         assert(std::has_facet<std::ctype<wchar_t> >(l));
         const std::ctype<wchar_t>& f = std::use_facet<std::ctype<wchar_t> >(l);
+        ((void)f); // Prevent unused warning
         {
             (void)std::ctype<wchar_t>::id;
         }
Index: test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp
+++ test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_long.pass.cpp
@@ -47,7 +47,6 @@
         std::ios ios(0);
         long v = 0;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0");
@@ -56,7 +55,6 @@
         std::ios ios(0);
         long v = 1;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1");
@@ -65,7 +63,6 @@
         std::ios ios(0);
         long v = -1;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "-1");
@@ -74,7 +71,6 @@
         std::ios ios(0);
         long v = -1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "-1000");
@@ -83,7 +79,6 @@
         std::ios ios(0);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1000");
@@ -93,7 +88,6 @@
         showpos(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "+1000");
@@ -103,7 +97,6 @@
         oct(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1750");
@@ -114,7 +107,6 @@
         showbase(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "01750");
@@ -124,7 +116,6 @@
         hex(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "3e8");
@@ -135,7 +126,6 @@
         showbase(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x3e8");
@@ -147,7 +137,6 @@
         uppercase(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0X3E8");
@@ -160,7 +149,6 @@
         uppercase(ios);
         long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0X3E_8");
@@ -172,7 +160,6 @@
         showbase(ios);
         long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x7f_fff_ff_f");
@@ -183,7 +170,6 @@
         oct(ios);
         long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "123_46_7");
@@ -195,7 +181,6 @@
         showbase(ios);
         long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0_123_46_7");
@@ -209,7 +194,6 @@
         ios.width(15);
         long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "*****0_123_46_7");
@@ -223,7 +207,6 @@
         ios.width(15);
         long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0_123_46_7*****");
@@ -237,7 +220,6 @@
         ios.width(15);
         long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "*****0_123_46_7");
@@ -252,7 +234,6 @@
         ios.width(15);
         long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "**0x7f_fff_ff_f");
@@ -266,7 +247,6 @@
         ios.width(15);
         long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x7f_fff_ff_f**");
@@ -280,7 +260,6 @@
         ios.width(15);
         long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x**7f_fff_ff_f");
@@ -294,7 +273,6 @@
         right(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "***+1_00_0");
@@ -308,7 +286,6 @@
         left(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "+1_00_0***");
@@ -322,7 +299,6 @@
         internal(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "+***1_00_0");
@@ -336,7 +312,6 @@
         showpos(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "***-1_00_0");
@@ -349,7 +324,6 @@
         left(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "-1_00_0***");
@@ -362,7 +336,6 @@
         internal(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "-***1_00_0");
Index: test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp
+++ test/std/localization/locale.categories/category.numeric/locale.nm.put/facet.num.put.members/put_unsigned_long.pass.cpp
@@ -47,7 +47,6 @@
         std::ios ios(0);
         unsigned long v = 0;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0");
@@ -56,7 +55,6 @@
         std::ios ios(0);
         unsigned long v = 1;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1");
@@ -65,7 +63,6 @@
         std::ios ios(0);
         unsigned long v = -1;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == (sizeof(unsigned long) == 4 ? "4294967295" : "18446744073709551615"));
@@ -74,7 +71,6 @@
         std::ios ios(0);
         unsigned long v = -1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == (sizeof(unsigned long) == 4 ? "4294966296" : "18446744073709550616"));
@@ -83,7 +79,6 @@
         std::ios ios(0);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1000");
@@ -93,7 +88,6 @@
         showpos(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1000");
@@ -103,7 +97,6 @@
         oct(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1750");
@@ -114,7 +107,6 @@
         showbase(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "01750");
@@ -124,7 +116,6 @@
         hex(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "3e8");
@@ -135,7 +126,6 @@
         showbase(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x3e8");
@@ -147,7 +137,6 @@
         uppercase(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0X3E8");
@@ -160,7 +149,6 @@
         uppercase(ios);
         unsigned long v = 1000;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0X3E_8");
@@ -172,7 +160,6 @@
         showbase(ios);
         unsigned long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x7f_fff_ff_f");
@@ -183,7 +170,6 @@
         oct(ios);
         unsigned long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "123_46_7");
@@ -195,7 +181,6 @@
         showbase(ios);
         unsigned long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0_123_46_7");
@@ -209,7 +194,6 @@
         ios.width(15);
         unsigned long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "*****0_123_46_7");
@@ -223,7 +207,6 @@
         ios.width(15);
         unsigned long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0_123_46_7*****");
@@ -237,7 +220,6 @@
         ios.width(15);
         unsigned long v = 0123467;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "*****0_123_46_7");
@@ -252,7 +234,6 @@
         ios.width(15);
         unsigned long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "**0x7f_fff_ff_f");
@@ -266,7 +247,6 @@
         ios.width(15);
         unsigned long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x7f_fff_ff_f**");
@@ -280,7 +260,6 @@
         ios.width(15);
         unsigned long v = 2147483647;
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "0x**7f_fff_ff_f");
@@ -294,7 +273,6 @@
         right(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "****1_00_0");
@@ -308,7 +286,6 @@
         left(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "1_00_0****");
@@ -322,7 +299,6 @@
         internal(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == "****1_00_0");
@@ -336,7 +312,6 @@
         showpos(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == (sizeof(unsigned long) == 4 ? "4_294_966_29_6"
@@ -350,7 +325,6 @@
         left(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == (sizeof(unsigned long) == 4 ? "4_294_966_29_6"
@@ -364,7 +338,6 @@
         internal(ios);
         ios.width(10);
         char str[50];
-        std::ios_base::iostate err = ios.goodbit;
         output_iterator<char*> iter = f.put(output_iterator<char*>(str), ios, '*', v);
         std::string ex(str, iter.base());
         assert(ex == (sizeof(unsigned long) == 4 ? "4_294_966_29_6"
Index: test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp
===================================================================
--- test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp
+++ test/std/localization/locale.categories/category.time/locale.time.get/time_base.pass.cpp
@@ -21,6 +21,7 @@
 int main()
 {
     std::time_base::dateorder d = std::time_base::no_order;
+    ((void)d); // Prevent unused warning
     assert(std::time_base::no_order == 0);
     assert(std::time_base::dmy == 1);
     assert(std::time_base::mdy == 2);
Index: test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp
===================================================================
--- test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp
+++ test/std/localization/locale.categories/facet.numpunct/locale.numpunct/types.pass.cpp
@@ -28,6 +28,7 @@
     {
         assert(std::has_facet<std::numpunct<char> >(l));
         const std::numpunct<char>& f = std::use_facet<std::numpunct<char> >(l);
+        ((void)f); // Prevent unused warning
         {
             (void)std::numpunct<char>::id;
         }
@@ -38,6 +39,7 @@
     {
         assert(std::has_facet<std::numpunct<wchar_t> >(l));
         const std::numpunct<wchar_t>& f = std::use_facet<std::numpunct<wchar_t> >(l);
+        ((void)f); // Prevent unused warning
         {
             (void)std::numpunct<wchar_t>::id;
         }
Index: test/std/localization/locales/locale.global.templates/use_facet.pass.cpp
===================================================================
--- test/std/localization/locales/locale.global.templates/use_facet.pass.cpp
+++ test/std/localization/locales/locale.global.templates/use_facet.pass.cpp
@@ -35,6 +35,7 @@
     try
     {
         const my_facet& f = std::use_facet<my_facet>(std::locale());
+        ((void)f); // Prevent unused warning
         assert(false);
     }
     catch (std::bad_cast&)
Index: test/std/numerics/c.math/ctgmath.pass.cpp
===================================================================
--- test/std/numerics/c.math/ctgmath.pass.cpp
+++ test/std/numerics/c.math/ctgmath.pass.cpp
@@ -15,4 +15,5 @@
 {
     std::complex<double> cd;
     double x = std::sin(0);
+    ((void)x); // Prevent unused warning
 }
Index: test/std/numerics/rand/rand.device/entropy.pass.cpp
===================================================================
--- test/std/numerics/rand/rand.device/entropy.pass.cpp
+++ test/std/numerics/rand/rand.device/entropy.pass.cpp
@@ -20,4 +20,5 @@
 {
     std::random_device r;
     double e = r.entropy();
+    ((void)e); // Prevent unused warning
 }
Index: test/std/numerics/rand/rand.device/eval.pass.cpp
===================================================================
--- test/std/numerics/rand/rand.device/eval.pass.cpp
+++ test/std/numerics/rand/rand.device/eval.pass.cpp
@@ -23,6 +23,7 @@
     {
         std::random_device r;
         std::random_device::result_type e = r();
+        ((void)e); // Prevent unused warning
     }
 
 #ifndef TEST_HAS_NO_EXCEPTIONS
Index: test/std/strings/basic.string/string.capacity/reserve.pass.cpp
===================================================================
--- test/std/strings/basic.string/string.capacity/reserve.pass.cpp
+++ test/std/strings/basic.string/string.capacity/reserve.pass.cpp
@@ -36,6 +36,7 @@
 test(S s, typename S::size_type res_arg)
 {
     typename S::size_type old_cap = s.capacity();
+    ((void)old_cap); // Prevent unused warning
     S s0 = s;
     if (res_arg <= s.max_size())
     {
Index: test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp
===================================================================
--- test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp
+++ test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp
@@ -39,6 +39,7 @@
         try
         {
             typename S::size_type r = cs.copy(s, n, pos);
+            ((void)r); // Prevent unused warning
             assert(false);
         }
         catch (std::out_of_range&)
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char/eq.pass.cpp
@@ -18,7 +18,6 @@
 
 int main()
 {
-    char c = '\0';
     assert(std::char_traits<char>::eq('a', 'a'));
     assert(!std::char_traits<char>::eq('a', 'A'));
 }
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eof.pass.cpp
@@ -20,5 +20,6 @@
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     std::char_traits<char16_t>::int_type i = std::char_traits<char16_t>::eof();
+    ((void)i); // Prevent unused warning
 #endif
 }
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/eq.pass.cpp
@@ -22,7 +22,6 @@
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
-    char16_t c = u'\0';
     assert(std::char_traits<char16_t>::eq(u'a', u'a'));
     assert(!std::char_traits<char16_t>::eq(u'a', u'A'));
 #endif
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char16_t/lt.pass.cpp
@@ -22,7 +22,6 @@
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
-    char16_t c = u'\0';
     assert(!std::char_traits<char16_t>::lt(u'a', u'a'));
     assert( std::char_traits<char16_t>::lt(u'A', u'a'));
 #endif
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eof.pass.cpp
@@ -20,5 +20,6 @@
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
     std::char_traits<char32_t>::int_type i = std::char_traits<char32_t>::eof();
+    ((void)i); // Prevent unused warning
 #endif
 }
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/eq.pass.cpp
@@ -22,7 +22,6 @@
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
-    char32_t c = U'\0';
     assert(std::char_traits<char32_t>::eq(U'a', U'a'));
     assert(!std::char_traits<char32_t>::eq(U'a', U'A'));
 #endif
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char32_t/lt.pass.cpp
@@ -22,7 +22,6 @@
 {
 #ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
 #if TEST_STD_VER >= 11
-    char32_t c = U'\0';
     assert(!std::char_traits<char32_t>::lt(U'a', U'a'));
     assert( std::char_traits<char32_t>::lt(U'A', U'a'));
 #endif
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/eq.pass.cpp
@@ -18,7 +18,6 @@
 
 int main()
 {
-    wchar_t c = L'\0';
     assert(std::char_traits<wchar_t>::eq(L'a', L'a'));
     assert(!std::char_traits<wchar_t>::eq(L'a', L'A'));
 }
Index: test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp
===================================================================
--- test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp
+++ test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.wchar.t/lt.pass.cpp
@@ -18,7 +18,6 @@
 
 int main()
 {
-    wchar_t c = L'\0';
     assert(!std::char_traits<wchar_t>::lt(L'a', L'a'));
     assert( std::char_traits<wchar_t>::lt(L'A', L'a'));
 }
Index: test/std/thread/futures/futures.promise/dtor.pass.cpp
===================================================================
--- test/std/thread/futures/futures.promise/dtor.pass.cpp
+++ test/std/thread/futures/futures.promise/dtor.pass.cpp
@@ -44,6 +44,7 @@
         try
         {
             T i = f.get();
+            ((void)i); // Prevent unused warning
             assert(false);
         }
         catch (const std::future_error& e)
@@ -75,6 +76,7 @@
         try
         {
             T i = f.get();
+            ((void)i); // Prevent unused warning
             assert(false);
         }
         catch (const std::future_error& e)
Index: test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp
===================================================================
--- test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp
+++ test/std/thread/futures/futures.task/futures.task.members/dtor.pass.cpp
@@ -50,6 +50,7 @@
         try
         {
             double i = f.get();
+            ((void)i); // Prevent unused warning
             assert(false);
         }
         catch (const std::future_error& e)
Index: test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
===================================================================
--- test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
+++ test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
@@ -52,6 +52,7 @@
     cv.notify_one();
     Clock::time_point t0 = Clock::now();
     bool r = cv.wait_for(lk, milliseconds(250), Pred(test2));
+    ((void)r); // Prevent unused warning
     Clock::time_point t1 = Clock::now();
     if (runs == 0)
     {