From e52905cf3c264ee454ca5978d7986bfd58bcb573 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Tue, 17 May 2016 18:43:41 +0300
Subject: [PATCH] Add intrusive_ptr converting move assignment.

---
 include/boost/smart_ptr/intrusive_ptr.hpp |  7 ++++++
 test/intrusive_ptr_move_test.cpp          | 27 +++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/include/boost/smart_ptr/intrusive_ptr.hpp b/include/boost/smart_ptr/intrusive_ptr.hpp
index dceb817..1e93397 100644
--- a/include/boost/smart_ptr/intrusive_ptr.hpp
+++ b/include/boost/smart_ptr/intrusive_ptr.hpp
@@ -139,6 +139,13 @@ public:
         rhs.px = 0;
     }
 
+    template<class U>
+    intrusive_ptr & operator=(intrusive_ptr<U> && rhs) BOOST_NOEXCEPT
+    {
+        this_type( static_cast< intrusive_ptr<U> && >( rhs ) ).swap(*this);
+        return *this;
+    }
+
 #endif
 
     intrusive_ptr & operator=(intrusive_ptr const & rhs)
diff --git a/test/intrusive_ptr_move_test.cpp b/test/intrusive_ptr_move_test.cpp
index c97bd11..2f2f652 100644
--- a/test/intrusive_ptr_move_test.cpp
+++ b/test/intrusive_ptr_move_test.cpp
@@ -182,6 +182,33 @@ int main()
         BOOST_TEST( N::base::instances == 0 );
     }
 
+    {
+        boost::intrusive_ptr<Y> p( new Y );
+        BOOST_TEST( N::base::instances == 1 );
+
+        boost::intrusive_ptr<X> p2;
+        p2 = std::move( p );
+        BOOST_TEST( N::base::instances == 1 );
+        BOOST_TEST( p.get() == 0 );
+
+        p2.reset();
+        BOOST_TEST( N::base::instances == 0 );
+    }
+
+    {
+        boost::intrusive_ptr<Y> p( new Y );
+        BOOST_TEST( N::base::instances == 1 );
+
+        boost::intrusive_ptr<X> p2( new X );
+        BOOST_TEST( N::base::instances == 2 );
+        p2 = std::move( p );
+        BOOST_TEST( N::base::instances == 1 );
+        BOOST_TEST( p.get() == 0 );
+
+        p2.reset();
+        BOOST_TEST( N::base::instances == 0 );
+    }
+
     return boost::report_errors();
 }