From 270082a7e126f727437c99ab8403185e9f29244c Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Thu, 14 Nov 2019 16:53:18 +0000
Subject: libstdc++: Implement new predicate concepts from P1716R3

	* include/bits/iterator_concepts.h (__iter_concept_impl): Add
	comments.
	(indirect_relation): Rename to indirect_binary_predicate and adjust
	definition as per P1716R3.
	(indirect_equivalence_relation): Define.
	(indirectly_comparable): Adjust definition.
	* include/std/concepts (equivalence_relation): Define.
	* testsuite/std/concepts/concepts.callable/relation.cc: Add tests for
	equivalence_relation.

From-SVN: r278256
---
 libstdc++-v3/include/std/concepts | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

(limited to 'libstdc++-v3/include/std/concepts')

diff --git a/libstdc++-v3/include/std/concepts b/libstdc++-v3/include/std/concepts
index c4acfd2..e6d405a 100644
--- a/libstdc++-v3/include/std/concepts
+++ b/libstdc++-v3/include/std/concepts
@@ -334,26 +334,30 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // [concepts.callable], callable concepts
 
-  // [concept.invocable], concept invocable
+  /// [concept.invocable], concept invocable
   template<typename _Fn, typename... _Args>
     concept invocable = is_invocable_v<_Fn, _Args...>;
 
-  // [concept.regularinvocable], concept regular_invocable
+  /// [concept.regularinvocable], concept regular_invocable
   template<typename _Fn, typename... _Args>
     concept regular_invocable = invocable<_Fn, _Args...>;
 
-  // [concept.predicate], concept predicate
+  /// [concept.predicate], concept predicate
   template<typename _Fn, typename... _Args>
     concept predicate = regular_invocable<_Fn, _Args...>
       && boolean<invoke_result_t<_Fn, _Args...>>;
 
-  // [concept.relation], concept relation
+  /// [concept.relation], concept relation
   template<typename _Rel, typename _Tp, typename _Up>
     concept relation
       = predicate<_Rel, _Tp, _Tp> && predicate<_Rel, _Up, _Up>
       && predicate<_Rel, _Tp, _Up> && predicate<_Rel, _Up, _Tp>;
 
-  // [concept.strictweakorder], concept strict_weak_order
+  /// [concept.equiv], concept equivalence_relation
+  template<typename _Rel, typename _Tp, typename _Up>
+    concept equivalence_relation = relation<_Rel, _Tp, _Up>;
+
+  /// [concept.strictweakorder], concept strict_weak_order
   template<typename _Rel, typename _Tp, typename _Up>
     concept strict_weak_order = relation<_Rel, _Tp, _Up>;
 
-- 
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