PR libstdc++/85749 constrain seed sequences for random number engines

Constrain constructors and member functions of random number engines so
that functions taking seed sequences can only be called with types that
meet the seed sequence requirements.

	PR libstdc++/85749
	* include/bits/random.h (__detail::__is_seed_seq): New SFINAE helper.
	(linear_congruential_engine, mersenne_twister_engine)
	(subtract_with_carry_engine, discard_block_engine)
	(independent_bits_engine, shuffle_order_engine): Use __is_seed_seq to
	constrain function templates taking seed sequences.
	* include/bits/random.tcc (linear_congruential_engine::seed(_Sseq&))
	(mersenne_twister_engine::seed(_Sseq&))
	(subtract_with_carry_engine::seed(_Sseq&)): Change return types to
	match declarations.
	* include/ext/random (simd_fast_mersenne_twister_engine): Use
	__is_seed_seq to constrain function templates taking seed sequences.
	* include/ext/random.tcc (simd_fast_mersenne_twister_engine::seed):
	Change return type to match declaration.
	* testsuite/26_numerics/random/discard_block_engine/cons/seed_seq2.cc:
	New.
	* testsuite/26_numerics/random/independent_bits_engine/cons/
	seed_seq2.cc: New.
	* testsuite/26_numerics/random/linear_congruential_engine/cons/
	seed_seq2.cc: New.
	* testsuite/26_numerics/random/mersenne_twister_engine/cons/
	seed_seq2.cc: New.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.
	* testsuite/26_numerics/random/shuffle_order_engine/cons/seed_seq2.cc:
	New.
	* testsuite/26_numerics/random/subtract_with_carry_engine/cons/
	seed_seq2.cc: New.
	* testsuite/ext/random/simd_fast_mersenne_twister_engine/cons/
	seed_seq2.cc: New.

From-SVN: r260263

4 files changed, 67 insertions, 36 deletions

diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index f812bbf..b76cfbb 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -185,6 +185,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	_Engine& _M_g;
       };
 
+    template<typename _Sseq>
+      using __seed_seq_generate_t = decltype(
+	  std::declval<_Sseq&>().generate(std::declval<uint_least32_t*>(),
+					  std::declval<uint_least32_t*>()));
+
+    // Detect whether _Sseq is a valid seed sequence for
+    // a random number engine _Engine with result type _Res.
+    template<typename _Sseq, typename _Engine, typename _Res,
+	     typename _GenerateCheck = __seed_seq_generate_t<_Sseq>>
+      using __is_seed_seq = __and_<
+        __not_<is_same<__remove_cvref_t<_Sseq>, _Engine>>,
+	is_unsigned<typename _Sseq::result_type>,
+	__not_<is_convertible<_Sseq, _Res>>
+      >;
+
   } // namespace __detail
 
   /**
@@ -233,6 +248,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       static_assert(__m == 0u || (__a < __m && __c < __m),
 		    "template argument substituting __m out of bounds");
 
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, linear_congruential_engine, _UIntType>::value>::type;
+
     public:
       /** The type of the generated random value. */
       typedef _UIntType result_type;
@@ -262,9 +281,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        * @param __q the seed sequence.
        */
-      template<typename _Sseq, typename = typename
-	std::enable_if<!std::is_same<_Sseq, linear_congruential_engine>::value>
-	       ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
         explicit
         linear_congruential_engine(_Sseq& __q)
         { seed(__q); }
@@ -286,7 +303,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        * @param __q the seed sequence.
        */
       template<typename _Sseq>
-        typename std::enable_if<std::is_class<_Sseq>::value>::type
+        _If_seed_seq<_Sseq>
         seed(_Sseq& __q);
 
       /**
@@ -463,6 +480,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       static_assert(__f <= (__detail::_Shift<_UIntType, __w>::__value - 1),
 		    "template argument substituting __f out of bound");
 
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, mersenne_twister_engine, _UIntType>::value>::type;
+
     public:
       /** The type of the generated random value. */
       typedef _UIntType result_type;
@@ -494,9 +515,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        * @param __q the seed sequence.
        */
-      template<typename _Sseq, typename = typename
-        std::enable_if<!std::is_same<_Sseq, mersenne_twister_engine>::value>
-	       ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
         explicit
         mersenne_twister_engine(_Sseq& __q)
         { seed(__q); }
@@ -505,7 +524,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       seed(result_type __sd = default_seed);
 
       template<typename _Sseq>
-	typename std::enable_if<std::is_class<_Sseq>::value>::type
+        _If_seed_seq<_Sseq>
         seed(_Sseq& __q);
 
       /**
@@ -658,6 +677,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       static_assert(0u < __w && __w <= std::numeric_limits<_UIntType>::digits,
 		    "template argument substituting __w out of bounds");
 
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, subtract_with_carry_engine, _UIntType>::value>::type;
+
     public:
       /** The type of the generated random value. */
       typedef _UIntType result_type;
@@ -682,9 +705,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        * @param __q the seed sequence.
        */
-      template<typename _Sseq, typename = typename
-        std::enable_if<!std::is_same<_Sseq, subtract_with_carry_engine>::value>
-	       ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
         explicit
         subtract_with_carry_engine(_Sseq& __q)
         { seed(__q); }
@@ -709,7 +730,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        * % subtract_with_carry_engine random number generator.
        */
       template<typename _Sseq>
-	typename std::enable_if<std::is_class<_Sseq>::value>::type
+	_If_seed_seq<_Sseq>
         seed(_Sseq& __q);
 
       /**
@@ -845,6 +866,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       /** The type of the generated random value. */
       typedef typename _RandomNumberEngine::result_type result_type;
 
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, discard_block_engine, result_type>::value>::type;
+
       // parameter values
       static constexpr size_t block_size = __p;
       static constexpr size_t used_block = __r;
@@ -892,10 +917,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        * @param __q A seed sequence.
        */
-      template<typename _Sseq, typename = typename
-	std::enable_if<!std::is_same<_Sseq, discard_block_engine>::value
-		       && !std::is_same<_Sseq, _RandomNumberEngine>::value>
-	       ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
         explicit
         discard_block_engine(_Sseq& __q)
 	: _M_b(__q), _M_n(0)
@@ -929,7 +951,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        * @param __q A seed generator function.
        */
       template<typename _Sseq>
-        void
+        _If_seed_seq<_Sseq>
         seed(_Sseq& __q)
         {
 	  _M_b.seed(__q);
@@ -1063,6 +1085,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       static_assert(0u < __w && __w <= std::numeric_limits<_UIntType>::digits,
 		    "template argument substituting __w out of bounds");
 
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, independent_bits_engine, _UIntType>::value>::type;
+
     public:
       /** The type of the generated random value. */
       typedef _UIntType result_type;
@@ -1110,10 +1136,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        * @param __q A seed sequence.
        */
-      template<typename _Sseq, typename = typename
-	std::enable_if<!std::is_same<_Sseq, independent_bits_engine>::value
-		       && !std::is_same<_Sseq, _RandomNumberEngine>::value>
-               ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
         explicit
         independent_bits_engine(_Sseq& __q)
         : _M_b(__q)
@@ -1141,7 +1164,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        * @param __q A seed generator function.
        */
       template<typename _Sseq>
-        void
+        _If_seed_seq<_Sseq>
         seed(_Sseq& __q)
         { _M_b.seed(__q); }
 
@@ -1283,6 +1306,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       /** The type of the generated random value. */
       typedef typename _RandomNumberEngine::result_type result_type;
 
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, shuffle_order_engine, result_type>::value>::type;
+
       static constexpr size_t table_size = __k;
 
       /**
@@ -1332,10 +1359,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        * @param __q A seed sequence.
        */
-      template<typename _Sseq, typename = typename
-	std::enable_if<!std::is_same<_Sseq, shuffle_order_engine>::value
-		       && !std::is_same<_Sseq, _RandomNumberEngine>::value>
-	       ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
         explicit
         shuffle_order_engine(_Sseq& __q)
         : _M_b(__q)
@@ -1369,7 +1393,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        * @param __q A seed generator function.
        */
       template<typename _Sseq>
-        void
+        _If_seed_seq<_Sseq>
         seed(_Sseq& __q)
         {
 	  _M_b.seed(__q);
diff --git a/libstdc++-v3/include/bits/random.tcc b/libstdc++-v3/include/bits/random.tcc
index f398150..9ec2989 100644
--- a/libstdc++-v3/include/bits/random.tcc
+++ b/libstdc++-v3/include/bits/random.tcc
@@ -128,9 +128,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
     template<typename _Sseq>
-      typename std::enable_if<std::is_class<_Sseq>::value>::type
+      auto
       linear_congruential_engine<_UIntType, __a, __c, __m>::
       seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
       {
 	const _UIntType __k0 = __m == 0 ? std::numeric_limits<_UIntType>::digits
 	                                : std::__lg(__m);
@@ -346,10 +347,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
 	   _UIntType __f>
     template<typename _Sseq>
-      typename std::enable_if<std::is_class<_Sseq>::value>::type
+      auto
       mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
 			      __s, __b, __t, __c, __l, __f>::
       seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
       {
 	const _UIntType __upper_mask = (~_UIntType()) << __r;
 	const size_t __k = (__w + 31) / 32;
@@ -564,9 +566,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   template<typename _UIntType, size_t __w, size_t __s, size_t __r>
     template<typename _Sseq>
-      typename std::enable_if<std::is_class<_Sseq>::value>::type
+      auto
       subtract_with_carry_engine<_UIntType, __w, __s, __r>::
       seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
       {
 	const size_t __k = (__w + 31) / 32;
 	uint_least32_t __arr[__r * __k];
diff --git a/libstdc++-v3/include/ext/random b/libstdc++-v3/include/ext/random
index 0a98b35..7e93186 100644
--- a/libstdc++-v3/include/ext/random
+++ b/libstdc++-v3/include/ext/random
@@ -85,6 +85,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       static_assert(16 % sizeof(_UIntType) == 0,
 		    "UIntType size must divide 16");
 
+      template<typename _Sseq>
+	using _If_seed_seq
+	  = typename std::enable_if<std::__detail::__is_seed_seq<
+	    _Sseq, simd_fast_mersenne_twister_engine, result_type>::value
+	    >::type;
+
     public:
       static constexpr size_t state_size = _M_nstate * (16
 							/ sizeof(result_type));
@@ -95,10 +101,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       simd_fast_mersenne_twister_engine(result_type __sd = default_seed)
       { seed(__sd); }
 
-      template<typename _Sseq, typename = typename
-	std::enable_if<!std::is_same<_Sseq,
-				     simd_fast_mersenne_twister_engine>::value>
-	       ::type>
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
 	explicit
 	simd_fast_mersenne_twister_engine(_Sseq& __q)
 	{ seed(__q); }
@@ -107,7 +110,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       seed(result_type __sd = default_seed);
 
       template<typename _Sseq>
-	typename std::enable_if<std::is_class<_Sseq>::value>::type
+	_If_seed_seq<_Sseq>
 	seed(_Sseq& __q);
 
       static constexpr result_type
diff --git a/libstdc++-v3/include/ext/random.tcc b/libstdc++-v3/include/ext/random.tcc
index 07857dd..d845f25 100644
--- a/libstdc++-v3/include/ext/random.tcc
+++ b/libstdc++-v3/include/ext/random.tcc
@@ -85,13 +85,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   uint32_t __parity1, uint32_t __parity2,
 	   uint32_t __parity3, uint32_t __parity4>
     template<typename _Sseq>
-      typename std::enable_if<std::is_class<_Sseq>::value>::type
+      auto
       simd_fast_mersenne_twister_engine<_UIntType, __m,
 					__pos1, __sl1, __sl2, __sr1, __sr2,
 					__msk1, __msk2, __msk3, __msk4,
 					__parity1, __parity2, __parity3,
 					__parity4>::
       seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
       {
 	size_t __lag;