From 5a7960da41fec497eb4203d71215bcb1077207a9 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 15 May 2018 16:36:46 +0100
Subject: 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
---
 libstdc++-v3/include/ext/random | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

(limited to 'libstdc++-v3/include/ext/random')

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
-- 
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