Add a pointer overload for detail::hash_range under msvc

benchmark/.gitignore

@@ -1,3 +1,4 @@
 enwik8
 enwik9
 *.exe
+*.obj

benchmark/unordered.cpp

@@ -13,6 +13,9 @@
 #ifdef HAVE_ABSEIL
 # include "absl/hash/hash.h"
 #endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
+#endif
 #ifdef HAVE_MULXP_HASH
 # include "mulxp_hash.hpp"
 #endif
@@ -210,6 +213,14 @@ struct mulxp3_hash_
     }
 };
 
+struct mulxp1_hash32_
+{
+    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
+    {
+        return mulxp1_hash32( (unsigned char const*)st.data(), st.size(), 0 );
+    }
+};
+
 struct mulxp3_hash32_
 {
     std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
@@ -245,11 +256,11 @@ template<class H, class V> void test_hash_speed( int N, V const& v )
 
 #if defined( _MSC_VER )
 
-    std::printf( "%53s : q=%20Iu, %lld ms\n", hash.c_str(), q, ms1 );
+    std::printf( "%57s : q=%20Iu, %lld ms\n", hash.c_str(), q, ms1 );
 
 #else
 
-    std::printf( "%53s : q=%20zu, %lld ms\n", hash.c_str(), q, ms1 );
+    std::printf( "%57s : q=%20zu, %lld ms\n", hash.c_str(), q, ms1 );
 
 #endif
 }
@@ -270,11 +281,11 @@ template<class H, class V> void test_hash_collision( int N, V const& v, std::siz
 
 #if defined( _MSC_VER )
 
-    std::printf( "%53s : c=%Iu\n", hash.c_str(), n - s.size() );
+    std::printf( "%57s : c=%Iu\n", hash.c_str(), n - s.size() );
 
 #else
 
-    std::printf( "%53s : c=%zu\n", hash.c_str(), n - s.size() );
+    std::printf( "%57s : c=%zu\n", hash.c_str(), n - s.size() );
 
 #endif
 }
@@ -327,11 +338,11 @@ template<class V, class S> void test4( int N, V const& v, char const * hash, S s
 
 #if defined( _MSC_VER )
 
-    std::printf( "%53s : n=%Iu, m=%Iu, c=%Iu, q=%Iu, %4lld + %4lld = %4lld ms\n", hash, n, m, c, q, ms1, ms2, ms1 + ms2 );
+    std::printf( "%57s : n=%Iu, m=%Iu, c=%Iu, q=%Iu, %4lld + %4lld = %4lld ms\n", hash, n, m, c, q, ms1, ms2, ms1 + ms2 );
 
 #else
 
-    std::printf( "%53s : n=%zu, m=%zu, c=%zu, q=%zu, %4lld + %4lld = %4lld ms\n", hash, n, m, c, q, ms1, ms2, ms1 + ms2 );
+    std::printf( "%57s : n=%zu, m=%zu, c=%zu, q=%zu, %4lld + %4lld = %4lld ms\n", hash, n, m, c, q, ms1, ms2, ms1 + ms2 );
 
 #endif
 }
@@ -383,11 +394,15 @@ int main()
 #ifdef HAVE_ABSEIL
     test_hash_speed<absl::Hash<std::string> >( N * 16, v );
 #endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+    test_hash_speed<ankerl::unordered_dense::hash<std::string> >( N * 16, v );
+#endif
 #ifdef HAVE_MULXP_HASH
     test_hash_speed<mulxp0_hash_>( N * 16, v );
     test_hash_speed<mulxp1_hash_>( N * 16, v );
     test_hash_speed<mulxp2_hash_>( N * 16, v );
     test_hash_speed<mulxp3_hash_>( N * 16, v );
+    test_hash_speed<mulxp1_hash32_>( N * 16, v );
     test_hash_speed<mulxp3_hash32_>( N * 16, v );
 #endif
 
@@ -418,11 +433,15 @@ int main()
 #ifdef HAVE_ABSEIL
         test_hash_collision<absl::Hash<std::string> >( N * 16, v, n );
 #endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+        test_hash_collision<ankerl::unordered_dense::hash<std::string> >( N * 16, v, n );
+#endif
 #ifdef HAVE_MULXP_HASH
         test_hash_collision<mulxp0_hash_>( N * 16, v, n );
         test_hash_collision<mulxp1_hash_>( N * 16, v, n );
         test_hash_collision<mulxp2_hash_>( N * 16, v, n );
         test_hash_collision<mulxp3_hash_>( N * 16, v, n );
+        test_hash_collision<mulxp1_hash32_>( N * 16, v, n );
         test_hash_collision<mulxp3_hash32_>( N * 16, v, n );
 #endif
     }
@@ -442,11 +461,15 @@ int main()
 #ifdef HAVE_ABSEIL
     test_container_speed<K, absl::Hash<std::string> >( N, v );
 #endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+    test_container_speed<K, ankerl::unordered_dense::hash<std::string> >( N, v );
+#endif
 #ifdef HAVE_MULXP_HASH
     test_container_speed<K, mulxp0_hash_>( N, v );
     test_container_speed<K, mulxp1_hash_>( N, v );
     test_container_speed<K, mulxp2_hash_>( N, v );
     test_container_speed<K, mulxp3_hash_>( N, v );
+    test_container_speed<K, mulxp1_hash32_>( N, v );
     test_container_speed<K, mulxp3_hash32_>( N, v );
 #endif
 

benchmark/unordered_flat.cpp

@@ -11,6 +11,9 @@
 #ifdef HAVE_ABSEIL
 # include "absl/hash/hash.h"
 #endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
+#endif
 #ifdef HAVE_MULXP_HASH
 # include "mulxp_hash.hpp"
 #endif
@@ -210,118 +213,6 @@ template<class Hash> BOOST_NOINLINE void test( char const* label )
     times.push_back( rec );
 }
 
-// mul31_hash
-
-struct mul31_hash
-{
-    // not avalanching
-
-    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-#if SIZE_MAX > UINT32_MAX
-        std::size_t h = 0xCBF29CE484222325ull;
-#else
-        std::size_t h = 0x811C9DC5u;
-#endif
-
-        for( std::size_t i = 0; i < n; ++i )
-        {
-            h = h * 31 + static_cast<unsigned char>( p[i] );
-        }
-
-        return h;
-    }
-};
-
-// mul31_x4_hash
-
-struct mul31_x4_hash
-{
-    // not avalanching
-
-    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-#if SIZE_MAX > UINT32_MAX
-        std::size_t h = 0xCBF29CE484222325ull;
-#else
-        std::size_t h = 0x811C9DC5u;
-#endif
-
-        while( n >= 4 )
-        {
-            h = h * (31u * 31u * 31u * 31u)
-                + static_cast<unsigned char>( p[0] ) * (31u * 31u * 31u)
-                + static_cast<unsigned char>( p[1] ) * (31u * 31u)
-                + static_cast<unsigned char>( p[2] ) * 31u
-                + static_cast<unsigned char>( p[3] );
-
-            p += 4;
-            n -= 4;
-        }
-
-        while( n > 0 )
-        {
-            h = h * 31u + static_cast<unsigned char>( *p );
-
-            ++p;
-            --n;
-        }
-
-        return h;
-    }
-};
-
-// mul31_x8_hash
-
-struct mul31_x8_hash
-{
-    // not avalanching
-
-    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-#if SIZE_MAX > UINT32_MAX
-        boost::uint64_t h = 0xCBF29CE484222325ull;
-#else
-        boost::uint64_t h = 0x811C9DC5u;
-#endif
-
-        while( n >= 8 )
-        {
-            h = h * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[0] ) * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[1] ) * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[2] ) * (31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[3] ) * (31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[4] ) * (31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[5] ) * (31ull * 31ull)
-                + static_cast<unsigned char>( p[6] ) * 31ull
-                + static_cast<unsigned char>( p[7] );
-
-            p += 8;
-            n -= 8;
-        }
-
-        while( n > 0 )
-        {
-            h = h * 31u + static_cast<unsigned char>( *p );
-
-            ++p;
-            --n;
-        }
-
-        return static_cast<std::size_t>( h );
-    }
-};
-
 // fnv1a_hash
 
 template<int Bits> struct fnv1a_hash_impl;
@@ -391,16 +282,6 @@ struct absl_hash: absl::Hash<std::string>
 
 #ifdef HAVE_MULXP_HASH
 
-struct mulxp0_hash_
-{
-    using is_avalanching = void;
-
-    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
-    {
-        return mulxp0_hash( (unsigned char const*)st.data(), st.size(), 0 );
-    }
-};
-
 struct mulxp1_hash_
 {
     using is_avalanching = void;
@@ -411,16 +292,6 @@ struct mulxp1_hash_
     }
 };
 
-struct mulxp2_hash_
-{
-    using is_avalanching = void;
-
-    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
-    {
-        return mulxp2_hash( (unsigned char const*)st.data(), st.size(), 0 );
-    }
-};
-
 struct mulxp3_hash_
 {
     using is_avalanching = void;
@@ -431,6 +302,24 @@ struct mulxp3_hash_
     }
 };
 
+struct mulxp1_hash32_
+{
+    using is_avalanching = void;
+
+    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
+    {
+        std::size_t r = mulxp1_hash32( (unsigned char const*)st.data(), st.size(), 0 );
+
+#if SIZE_MAX > UINT32_MAX
+
+        r |= r << 32;
+
+#endif
+
+        return r;
+    }
+};
+
 struct mulxp3_hash32_
 {
     using is_avalanching = void;
@@ -459,9 +348,6 @@ int main()
 
     test< boost::hash<std::string> >( "boost::hash" );
     test< std_hash >( "std::hash" );
-    test< mul31_hash >( "mul31_hash" );
-    test< mul31_x4_hash >( "mul31_x4_hash" );
-    test< mul31_x8_hash >( "mul31_x8_hash" );
     test< fnv1a_hash >( "fnv1a_hash" );
 
 #ifdef HAVE_ABSEIL
@@ -470,12 +356,17 @@ int main()
 
 #endif
 
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test< ankerl::unordered_dense::hash<std::string> >( "ankerl::unordered_dense::hash" );
+
+#endif
+
 #ifdef HAVE_MULXP_HASH
 
-    test< mulxp0_hash_ >( "mulxp0_hash" );
     test< mulxp1_hash_ >( "mulxp1_hash" );
-    test< mulxp2_hash_ >( "mulxp2_hash" );
     test< mulxp3_hash_ >( "mulxp3_hash" );
+    test< mulxp1_hash32_ >( "mulxp1_hash32" );
     test< mulxp3_hash32_ >( "mulxp3_hash32" );
 
 #endif
@@ -484,7 +375,7 @@ int main()
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 22 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms\n";
+        std::cout << std::setw( 32 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms\n";
     }
 }
 

benchmark/word_count.cpp

@@ -9,6 +9,9 @@
 #ifdef HAVE_ABSEIL
 # include "absl/hash/hash.h"
 #endif
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+# include "ankerl/unordered_dense.h"
+#endif
 #ifdef HAVE_MULXP_HASH
 # include "mulxp_hash.hpp"
 #endif
@@ -38,8 +41,16 @@ static std::vector<std::string> words;
 
 static void init_words()
 {
+#if SIZE_MAX > UINT32_MAX
+
     char const* fn = "enwik9"; // http://mattmahoney.net/dc/textdata
 
+#else
+
+    char const* fn = "enwik8"; // ditto
+
+#endif
+
     auto t1 = std::chrono::steady_clock::now();
 
     std::ifstream is( fn );
@@ -137,118 +148,6 @@ template<class Hash> BOOST_NOINLINE void test( char const* label )
     times.push_back( rec );
 }
 
-// mul31_hash
-
-struct mul31_hash
-{
-    // not avalanching
-
-    std::size_t operator()( std::string_view const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-#if SIZE_MAX > UINT32_MAX
-        std::size_t h = 0xCBF29CE484222325ull;
-#else
-        std::size_t h = 0x811C9DC5u;
-#endif
-
-        for( std::size_t i = 0; i < n; ++i )
-        {
-            h = h * 31 + static_cast<unsigned char>( p[i] );
-        }
-
-        return h;
-    }
-};
-
-// mul31_x4_hash
-
-struct mul31_x4_hash
-{
-    // not avalanching
-
-    std::size_t operator()( std::string_view const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-#if SIZE_MAX > UINT32_MAX
-        std::size_t h = 0xCBF29CE484222325ull;
-#else
-        std::size_t h = 0x811C9DC5u;
-#endif
-
-        while( n >= 4 )
-        {
-            h = h * (31u * 31u * 31u * 31u)
-                + static_cast<unsigned char>( p[0] ) * (31u * 31u * 31u)
-                + static_cast<unsigned char>( p[1] ) * (31u * 31u)
-                + static_cast<unsigned char>( p[2] ) * 31u
-                + static_cast<unsigned char>( p[3] );
-
-            p += 4;
-            n -= 4;
-        }
-
-        while( n > 0 )
-        {
-            h = h * 31u + static_cast<unsigned char>( *p );
-
-            ++p;
-            --n;
-        }
-
-        return h;
-    }
-};
-
-// mul31_x8_hash
-
-struct mul31_x8_hash
-{
-    // not avalanching
-
-    std::size_t operator()( std::string_view const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-#if SIZE_MAX > UINT32_MAX
-        boost::uint64_t h = 0xCBF29CE484222325ull;
-#else
-        boost::uint64_t h = 0x811C9DC5u;
-#endif
-
-        while( n >= 8 )
-        {
-            h = h * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[0] ) * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[1] ) * (31ull * 31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[2] ) * (31ull * 31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[3] ) * (31ull * 31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[4] ) * (31ull * 31ull * 31ull)
-                + static_cast<unsigned char>( p[5] ) * (31ull * 31ull)
-                + static_cast<unsigned char>( p[6] ) * 31ull
-                + static_cast<unsigned char>( p[7] );
-
-            p += 8;
-            n -= 8;
-        }
-
-        while( n > 0 )
-        {
-            h = h * 31u + static_cast<unsigned char>( *p );
-
-            ++p;
-            --n;
-        }
-
-        return static_cast<std::size_t>( h );
-    }
-};
-
 // fnv1a_hash
 
 template<int Bits> struct fnv1a_hash_impl;
@@ -316,16 +215,6 @@ struct absl_hash: absl::Hash<std::string_view>
 
 #ifdef HAVE_MULXP_HASH
 
-struct mulxp0_hash_
-{
-    using is_avalanching = void;
-
-    std::size_t operator()( std::string_view const& st ) const BOOST_NOEXCEPT
-    {
-        return mulxp0_hash( (unsigned char const*)st.data(), st.size(), 0 );
-    }
-};
-
 struct mulxp1_hash_
 {
     using is_avalanching = void;
@@ -336,16 +225,6 @@ struct mulxp1_hash_
     }
 };
 
-struct mulxp2_hash_
-{
-    using is_avalanching = void;
-
-    std::size_t operator()( std::string_view const& st ) const BOOST_NOEXCEPT
-    {
-        return mulxp2_hash( (unsigned char const*)st.data(), st.size(), 0 );
-    }
-};
-
 struct mulxp3_hash_
 {
     using is_avalanching = void;
@@ -374,6 +253,24 @@ struct mulxp3_hash32_
     }
 };
 
+struct mulxp1_hash32_
+{
+    using is_avalanching = void;
+
+    std::size_t operator()( std::string_view const& st ) const BOOST_NOEXCEPT
+    {
+        std::size_t r = mulxp1_hash32( (unsigned char const*)st.data(), st.size(), 0 );
+
+#if SIZE_MAX > UINT32_MAX
+
+        r |= r << 32;
+
+#endif
+
+        return r;
+    }
+};
+
 #endif
 
 //
@@ -384,9 +281,6 @@ int main()
 
     test< boost::hash<std::string_view> >( "boost::hash" );
     test< std_hash >( "std::hash" );
-    test< mul31_hash >( "mul31_hash" );
-    test< mul31_x4_hash >( "mul31_x4_hash" );
-    test< mul31_x8_hash >( "mul31_x8_hash" );
     test< fnv1a_hash >( "fnv1a_hash" );
 
 #ifdef HAVE_ABSEIL
@@ -395,12 +289,17 @@ int main()
 
 #endif
 
+#ifdef HAVE_ANKERL_UNORDERED_DENSE
+
+    test< ankerl::unordered_dense::hash<std::string_view> >( "ankerl::unordered_dense::hash" );
+
+#endif
+
 #ifdef HAVE_MULXP_HASH
 
-    test< mulxp0_hash_ >( "mulxp0_hash" );
     test< mulxp1_hash_ >( "mulxp1_hash" );
-    test< mulxp2_hash_ >( "mulxp2_hash" );
     test< mulxp3_hash_ >( "mulxp3_hash" );
+    test< mulxp1_hash32_ >( "mulxp1_hash32" );
     test< mulxp3_hash32_ >( "mulxp3_hash32" );
 
 #endif
@@ -409,7 +308,7 @@ int main()
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 22 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms\n";
+        std::cout << std::setw( 32 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms\n";
     }
 }
 

doc/hash/intro.adoc

@@ -22,11 +22,13 @@ Out of the box, `boost::hash` supports
 
 * standard integral types (integers, character types, and `bool`);
 * standard floating point types (`float`, `double`, `long double`);
-* pointers (to objects and to functions, but not pointers to members);
+* pointers (to objects and to functions, but not pointers to members)
+  and `nullptr`;
 * enumeration types;
 * C arrays;
 * `std::complex`;
-* `std::pair`, `std::tuple`;
+* tuple-like types, such as `std::pair`, `std::tuple`, and user-defined
+  types that specialize `std::tuple_size` and provide `get<I>`;
 * sequence-like types, both standard and user-defined (sequence-like types
   have `begin()` and `end()` member functions returning iterators);
 * unordered sequences, standard or user-defined (sequences for which the hash

doc/hash/recent.adoc

@@ -8,6 +8,12 @@ https://www.boost.org/LICENSE_1_0.txt
 = Recent Changes
 :idprefix: recent_
 
+== Boost 1.82.0
+
+* Added an overload of `hash_value` for `std::nullptr_t`.
+* Added `is_tuple_like` and an overload of `hash_value` for
+  tuple-like types.
+
 == Boost 1.81.0
 
 Major update.

doc/hash/reference.adoc

@@ -30,6 +30,7 @@ template<class T> struct is_range;
 template<class T> struct is_contiguous_range;
 template<class T> struct is_unordered_range;
 template<class T> struct is_described_class;
+template<class T> struct is_tuple_like;
 
 } // namespace container_hash
 
@@ -89,8 +90,9 @@ template<class T>
 template<class A, class B>
   std::size_t hash_value( std::pair<A, B> const& v );
 
-template<class... T>
-  std::size_t hash_value( std::tuple<T...> const& v );
+// Enabled only when container_hash::is_tuple_like<T>::value is true
+template<class T>
+  std::size_t hash_value( T const& v );
 
 // Enabled only when container_hash::is_range<T>::value is true
 template<class T>
@@ -385,8 +387,9 @@ return seed;
 
 [source]
 ----
-template<class... T>
-  std::size_t hash_value( std::tuple<T...> const& v );
+// Enabled only when container_hash::is_tuple_like<T>::value is true
+template<class T>
+  std::size_t hash_value( T const& v );
 ----
 
 Effects: ::
@@ -395,15 +398,21 @@ Effects: ::
 ----
 std::size_t seed = 0;
 
-boost::hash_combine( seed, std::get<0>(v) );
-boost::hash_combine( seed, std::get<1>(v) );
+using std::get;
+
+boost::hash_combine( seed, get<0>(v) );
+boost::hash_combine( seed, get<1>(v) );
 // ...
-boost::hash_combine( seed, std::get<N-1>(v) );
+boost::hash_combine( seed, get<N-1>(v) );
 
 return seed;
 ----
 +
-where `N` is `sizeof...(T)`.
+where `N` is `std::tuple_size<T>::value`.
+
+Remarks: ::
+This overload is only enabled when
+`container_hash::is_range<T>::value` is `false`.
 
 [source]
 ----
@@ -703,3 +712,38 @@ template<class T> struct is_described_class
 
 Users are allowed to specialize `is_described_class` for their types
 if the default behavior does not deduce the correct value.
+
+== <boost/container_hash/{zwsp}is_tuple_like.hpp>
+
+Defines the trait `boost::container_hash::is_tuple_like`.
+
+[source]
+----
+namespace boost
+{
+
+namespace container_hash
+{
+
+template<class T> struct is_tuple_like;
+
+} // namespace container_hash
+
+} // namespace boost
+----
+
+=== is_tuple_like<T>
+
+[source]
+----
+template<class T> struct is_tuple_like
+{
+    static constexpr bool value = /* see below */;
+};
+----
+
+`is_tuple_like<T>::value` is `true` when `std::tuple_size<T>::value`
+is valid.
+
+Users are allowed to specialize `is_tuple_like` for their types
+if the default behavior does not deduce the correct value.

include/boost/container_hash/detail/hash_range.hpp

@@ -10,9 +10,10 @@
 #include <boost/type_traits/enable_if.hpp>
 #include <boost/type_traits/is_same.hpp>
 #include <boost/cstdint.hpp>
+#include <iterator>
 #include <cstddef>
 #include <climits>
-#include <iterator>
+#include <cstring>
 
 namespace boost
 {
@@ -116,6 +117,67 @@ std::size_t>::type
     return seed;
 }
 
+#if defined(_MSC_VER) && !defined(__clang__)
+
+template<class T>
+inline typename boost::enable_if_<is_char_type<T>::value, std::size_t>::type
+    hash_range( std::size_t seed, T const* first, T const* last )
+{
+    std::size_t n = static_cast<std::size_t>( last - first );
+
+    for( ; n >= 4; first += 4, n -= 4 )
+    {
+        boost::uint32_t w;
+
+        std::memcpy( &w, first, 4 );
+
+        hash_combine( seed, w );
+    }
+
+    {
+        // add a trailing suffix byte of 0x01 because otherwise sequences of
+        // trailing zeroes are indistinguishable from end of string
+
+        boost::uint32_t w = 0x01u;
+
+        switch( n )
+        {
+        case 1:
+
+            w =
+                static_cast<boost::uint32_t>( static_cast<unsigned char>( first[0] ) ) |
+                0x0100u;
+
+            break;
+
+        case 2:
+
+            w =
+                static_cast<boost::uint32_t>( static_cast<unsigned char>( first[0] ) ) |
+                static_cast<boost::uint32_t>( static_cast<unsigned char>( first[1] ) ) <<  8 |
+                0x010000u;
+
+            break;
+
+        case 3:
+
+            w =
+                static_cast<boost::uint32_t>( static_cast<unsigned char>( first[0] ) ) |
+                static_cast<boost::uint32_t>( static_cast<unsigned char>( first[1] ) ) <<  8 |
+                static_cast<boost::uint32_t>( static_cast<unsigned char>( first[2] ) ) << 16 |
+                0x01000000u;
+
+            break;
+        }
+
+        hash_combine( seed, w );
+    }
+
+    return seed;
+}
+
+#endif
+
 template<class It>
 inline typename boost::enable_if_<
     is_char_type<typename std::iterator_traits<It>::value_type>::value &&

include/boost/container_hash/detail/hash_tuple.hpp

@@ -1,133 +0,0 @@
-// Copyright 2005-2009 Daniel James.
-// Copyright 2021 Peter Dimov.
-// Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt
-
-#ifndef BOOST_HASH_DETAIL_HASH_TUPLE_LIKE_HPP
-#define BOOST_HASH_DETAIL_HASH_TUPLE_LIKE_HPP
-
-#include <boost/container_hash/hash_fwd.hpp>
-#include <boost/type_traits/enable_if.hpp>
-#include <boost/config.hpp>
-
-#if defined(BOOST_NO_CXX11_HDR_TUPLE)
-
-// no support
-
-#else
-
-#include <tuple>
-
-namespace boost
-{
-namespace hash_detail
-{
-
-template <std::size_t I, typename T>
-inline typename boost::enable_if_<(I == std::tuple_size<T>::value),
-        void>::type
-    hash_combine_tuple(std::size_t&, T const&)
-{
-}
-
-template <std::size_t I, typename T>
-inline typename boost::enable_if_<(I < std::tuple_size<T>::value),
-        void>::type
-    hash_combine_tuple(std::size_t& seed, T const& v)
-{
-    boost::hash_combine(seed, std::get<I>(v));
-    boost::hash_detail::hash_combine_tuple<I + 1>(seed, v);
-}
-
-template <typename T>
-inline std::size_t hash_tuple(T const& v)
-{
-    std::size_t seed = 0;
-    boost::hash_detail::hash_combine_tuple<0>(seed, v);
-    return seed;
-}
-
-} // namespace hash_detail
-
-#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
-
-template <typename... T>
-inline std::size_t hash_value(std::tuple<T...> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-#else
-
-inline std::size_t hash_value(std::tuple<> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0>
-inline std::size_t hash_value(std::tuple<A0> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1>
-inline std::size_t hash_value(std::tuple<A0, A1> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2>
-inline std::size_t hash_value(std::tuple<A0, A1, A2> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3, typename A4>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3, A4> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3, A4, A5> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3, A4, A5, A6> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3, A4, A5, A6, A7> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7, typename A8>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3, A4, A5, A6, A7, A8> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7, typename A8, typename A9>
-inline std::size_t hash_value(std::tuple<A0, A1, A2, A3, A4, A5, A6, A7, A8, A9> const& v)
-{
-    return boost::hash_detail::hash_tuple(v);
-}
-
-#endif // #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
-
-} // namespace boost
-
-#endif // #if defined(BOOST_NO_CXX11_HDR_TUPLE)
-
-#endif // #ifndef BOOST_HASH_DETAIL_HASH_TUPLE_LIKE_HPP

include/boost/container_hash/detail/hash_tuple_like.hpp

@@ -0,0 +1,156 @@
+// Copyright 2005-2009 Daniel James.
+// Copyright 2021 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#ifndef BOOST_HASH_DETAIL_HASH_TUPLE_LIKE_HPP
+#define BOOST_HASH_DETAIL_HASH_TUPLE_LIKE_HPP
+
+#include <boost/container_hash/hash_fwd.hpp>
+#include <boost/container_hash/is_tuple_like.hpp>
+#include <boost/container_hash/is_range.hpp>
+#include <boost/type_traits/enable_if.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+#if defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+// no support for tuple-likes
+
+#else
+
+#include <tuple>
+
+namespace boost
+{
+namespace hash_detail
+{
+
+template <std::size_t I, typename T>
+inline
+typename boost::enable_if_<(I == std::tuple_size<T>::value), void>::type
+    hash_combine_tuple_like( std::size_t&, T const& )
+{
+}
+
+template <std::size_t I, typename T>
+inline
+typename boost::enable_if_<(I < std::tuple_size<T>::value), void>::type
+    hash_combine_tuple_like( std::size_t& seed, T const& v )
+{
+    using std::get;
+    boost::hash_combine( seed, get<I>( v ) );
+
+    boost::hash_detail::hash_combine_tuple_like<I + 1>( seed, v );
+}
+
+template <typename T>
+inline std::size_t hash_tuple_like( T const& v )
+{
+    std::size_t seed = 0;
+
+    boost::hash_detail::hash_combine_tuple_like<0>( seed, v );
+
+    return seed;
+}
+
+} // namespace hash_detail
+
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1800)
+
+template <class T>
+inline
+typename boost::enable_if_<
+    container_hash::is_tuple_like<T>::value && !container_hash::is_range<T>::value,
+std::size_t>::type
+    hash_value( T const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+#else
+
+template <typename... T>
+inline std::size_t hash_value( std::tuple<T...> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+#endif
+
+#else
+
+inline std::size_t hash_value( std::tuple<> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0>
+inline std::size_t hash_value( std::tuple<A0> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1>
+inline std::size_t hash_value( std::tuple<A0, A1> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2>
+inline std::size_t hash_value( std::tuple<A0, A1, A2> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3, typename A4>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3, A4> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3, A4, A5> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3, A4, A5, A6> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3, A4, A5, A6, A7> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7, typename A8>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3, A4, A5, A6, A7, A8> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+template<typename A0, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7, typename A8, typename A9>
+inline std::size_t hash_value( std::tuple<A0, A1, A2, A3, A4, A5, A6, A7, A8, A9> const& v )
+{
+    return boost::hash_detail::hash_tuple_like( v );
+}
+
+#endif // #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+
+} // namespace boost
+
+#endif // #if defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+#endif // #ifndef BOOST_HASH_DETAIL_HASH_TUPLE_LIKE_HPP

include/boost/container_hash/hash.hpp

@@ -15,7 +15,7 @@
 #include <boost/container_hash/is_contiguous_range.hpp>
 #include <boost/container_hash/is_unordered_range.hpp>
 #include <boost/container_hash/is_described_class.hpp>
-#include <boost/container_hash/detail/hash_tuple.hpp>
+#include <boost/container_hash/detail/hash_tuple_like.hpp>
 #include <boost/container_hash/detail/hash_mix.hpp>
 #include <boost/container_hash/detail/hash_range.hpp>
 #include <boost/type_traits/is_enum.hpp>

include/boost/container_hash/hash_fwd.hpp

@@ -18,6 +18,7 @@ template<class T> struct is_range;
 template<class T> struct is_contiguous_range;
 template<class T> struct is_unordered_range;
 template<class T> struct is_described_class;
+template<class T> struct is_tuple_like;
 
 } // namespace container_hash
 

include/boost/container_hash/is_tuple_like.hpp

@@ -0,0 +1,42 @@
+#ifndef BOOST_HASH_IS_TUPLE_LIKE_HPP_INCLUDED
+#define BOOST_HASH_IS_TUPLE_LIKE_HPP_INCLUDED
+
+// Copyright 2017, 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/type_traits/integral_constant.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <utility>
+
+namespace boost
+{
+namespace hash_detail
+{
+
+template<class T, class E = true_type> struct is_tuple_like_: false_type
+{
+};
+
+#if !defined(BOOST_NO_CXX11_HDR_TUPLE) && !BOOST_WORKAROUND(BOOST_MSVC, <= 1800)
+
+template<class T> struct is_tuple_like_<T, integral_constant<bool, std::tuple_size<T>::value == std::tuple_size<T>::value> >: true_type
+{
+};
+
+#endif
+
+} // namespace hash_detail
+
+namespace container_hash
+{
+
+template<class T> struct is_tuple_like: hash_detail::is_tuple_like_<T>
+{
+};
+
+} // namespace container_hash
+} // namespace boost
+
+#endif // #ifndef BOOST_HASH_IS_TUPLE_LIKE_HPP_INCLUDED

test/Jamfile.v2

@@ -119,3 +119,9 @@ run hash_is_avalanching_test2.cpp ;
 run hash_integral_test2.cpp ;
 
 run hash_nullptr_test.cpp ;
+
+run is_tuple_like_test.cpp ;
+
+run hash_tuple_like_test.cpp ;
+run hash_tuple_like_test2.cpp
+  : : : <warnings>extra ;

test/hash_tuple_like_test.cpp

@@ -0,0 +1,204 @@
+// Copyright 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__clang__)
+# pragma clang diagnostic ignored "-Wmismatched-tags"
+#endif
+
+#include <boost/container_hash/hash.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/type_traits/enable_if.hpp>
+#include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/integral_constant.hpp>
+#include <boost/config.hpp>
+#include <utility>
+
+#if !defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+#include <tuple>
+
+namespace user
+{
+
+struct Y1
+{
+    int a;
+    int b;
+};
+
+template<std::size_t I> int& get( Y1& v );
+template<std::size_t I> int const& get( Y1 const& v );
+
+template<> int& get<0>( Y1& v )
+{
+    return v.a;
+}
+
+template<> int const& get<0>( Y1 const& v )
+{
+    return v.a;
+}
+
+template<> int& get<1>( Y1& v )
+{
+    return v.b;
+}
+
+template<> int const& get<1>( Y1 const& v )
+{
+    return v.b;
+}
+
+struct Y2
+{
+    int a;
+    int b;
+
+    template<class T> friend
+        typename boost::enable_if_<boost::is_same<T, Y2>::value, std::size_t>::type
+        hash_value( T const& v )
+    {
+        std::size_t seed = 0;
+
+        boost::hash_combine( seed, v.a );
+        boost::hash_combine( seed, v.b );
+
+        return seed;
+    }
+};
+
+} // namespace user
+
+namespace std
+{
+
+template<> struct tuple_size<user::Y1>: std::integral_constant<std::size_t, 2>
+{
+};
+
+template<> struct tuple_size<user::Y2>: std::integral_constant<std::size_t, 2>
+{
+};
+
+} // namespace std
+
+namespace boost
+{
+namespace container_hash
+{
+
+    template<> struct is_tuple_like<user::Y2>: boost::false_type {};
+
+} // namespace container_hash
+} // namespace boost
+
+#endif
+
+template<class T> std::size_t hv( T const& t )
+{
+    return boost::hash<T>()( t );
+}
+
+int main()
+{
+    {
+        std::pair<int, int> tp( 1, 2 );
+        int const a[] = { 1, 2 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+#if !defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+    {
+        std::tuple<> tp;
+
+        BOOST_TEST_EQ( hv(tp), 0u );
+    }
+
+    {
+        std::tuple<int> tp( 1 );
+        int const a[] = { 1 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int> tp( 1, 2 );
+        int const a[] = { 1, 2 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int> tp( 1, 2, 3 );
+        int const a[] = { 1, 2, 3 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int, int> tp( 1, 2, 3, 4 );
+        int const a[] = { 1, 2, 3, 4 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int, int, int> tp( 1, 2, 3, 4, 5 );
+        int const a[] = { 1, 2, 3, 4, 5 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int, int, int, int> tp( 1, 2, 3, 4, 5, 6 );
+        int const a[] = { 1, 2, 3, 4, 5, 6 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int, int, int, int, int> tp( 1, 2, 3, 4, 5, 6, 7 );
+        int const a[] = { 1, 2, 3, 4, 5, 6, 7 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int, int, int, int, int, int> tp( 1, 2, 3, 4, 5, 6, 7, 8 );
+        int const a[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    {
+        std::tuple<int, int, int, int, int, int, int, int, int> tp( 1, 2, 3, 4, 5, 6, 7, 8, 9 );
+        int const a[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1800)
+
+    {
+        user::Y1 tp = { 1, 2 };
+        int const a[] = { 1, 2 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+#endif
+
+    {
+        user::Y2 tp = { 1, 2 };
+        int const a[] = { 1, 2 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+#endif
+
+    return boost::report_errors();
+}

test/hash_tuple_like_test2.cpp

@@ -0,0 +1,78 @@
+// Copyright 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__clang__)
+# pragma clang diagnostic ignored "-Wmismatched-tags"
+#endif
+
+#include <boost/container_hash/hash.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/type_traits/integral_constant.hpp>
+#include <boost/describe/class.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <utility>
+
+#if defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+BOOST_PRAGMA_MESSAGE( "Skipping test because BOOST_NO_CXX11_HDR_TUPLE is defined" )
+int main() {}
+
+#elif !defined(BOOST_DESCRIBE_CXX14)
+
+BOOST_PRAGMA_MESSAGE( "Skipping test because BOOST_DESCRIBE_CXX14 is not defined" )
+int main() {}
+
+#else
+
+namespace user
+{
+
+struct Y3
+{
+    int a;
+    int b;
+};
+
+BOOST_DESCRIBE_STRUCT(Y3, (), (a, b))
+
+} // namespace user
+
+namespace std
+{
+
+template<> struct tuple_size<user::Y3>: std::integral_constant<std::size_t, 2>
+{
+};
+
+} // namespace std
+
+namespace boost
+{
+namespace container_hash
+{
+
+    template<> struct is_tuple_like<user::Y3>: boost::false_type {};
+
+} // namespace container_hash
+} // namespace boost
+
+template<class T> std::size_t hv( T const& t )
+{
+    return boost::hash<T>()( t );
+}
+
+int main()
+{
+    {
+        user::Y3 tp = { 1, 2 };
+        int const a[] = { 1, 2 };
+
+        BOOST_TEST_EQ( hv(tp), hv(a) );
+    }
+
+    return boost::report_errors();
+}
+
+#endif

test/is_tuple_like_test.cpp

@@ -0,0 +1,91 @@
+// Copyright 2017, 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__clang__)
+# pragma clang diagnostic ignored "-Wmismatched-tags"
+#endif
+
+#include <boost/container_hash/is_tuple_like.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <utility>
+
+struct X
+{
+};
+
+#if !defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+#include <tuple>
+
+namespace user
+{
+
+struct Y
+{
+    int a;
+    int b;
+};
+
+template<std::size_t I> int& get( Y& v );
+template<std::size_t I> int const& get( Y const& v );
+
+template<> int& get<0>( Y& v )
+{
+    return v.a;
+}
+
+template<> int const& get<0>( Y const& v )
+{
+    return v.a;
+}
+
+template<> int& get<1>( Y& v )
+{
+    return v.b;
+}
+
+template<> int const& get<1>( Y const& v )
+{
+    return v.b;
+}
+
+} // namespace user
+
+namespace std
+{
+
+template<> struct tuple_size<user::Y>: std::integral_constant<std::size_t, 2>
+{
+};
+
+} // namespace std
+
+#endif // #if !defined(BOOST_NO_CXX11_HDR_TUPLE)
+
+int main()
+{
+    using boost::container_hash::is_tuple_like;
+
+    BOOST_TEST_TRAIT_FALSE((is_tuple_like<void>));
+    BOOST_TEST_TRAIT_FALSE((is_tuple_like<int>));
+    BOOST_TEST_TRAIT_FALSE((is_tuple_like<X>));
+    BOOST_TEST_TRAIT_FALSE((is_tuple_like<int[2]>));
+
+#if !defined(BOOST_NO_CXX11_HDR_TUPLE) && !BOOST_WORKAROUND(BOOST_MSVC, <= 1800)
+
+    BOOST_TEST_TRAIT_TRUE((is_tuple_like< std::pair<int, X> >));
+
+    BOOST_TEST_TRAIT_TRUE((is_tuple_like< std::tuple<> >));
+    BOOST_TEST_TRAIT_TRUE((is_tuple_like< std::tuple<X> >));
+    BOOST_TEST_TRAIT_TRUE((is_tuple_like< std::tuple<X, X> >));
+    BOOST_TEST_TRAIT_TRUE((is_tuple_like< std::tuple<X, X, X> >));
+
+    BOOST_TEST_TRAIT_TRUE((is_tuple_like<user::Y>));
+
+#endif
+
+    return boost::report_errors();
+}