Move the unique_ptr deleter instead of copying it

include/boost/smart_ptr/detail/shared_count.hpp

@@ -387,8 +387,8 @@ public:
     {
         typedef typename sp_convert_reference<D>::type D2;
 
-        D2 d2( r.get_deleter() );
+        D2 d2( static_cast<D&&>( r.get_deleter() ) );
-        pi_ = new sp_counted_impl_pd< typename std::unique_ptr<Y, D>::pointer, D2 >( r.get(), d2 );
+        pi_ = new sp_counted_impl_pd< typename std::unique_ptr<Y, D>::pointer, D2 >( r.get(), static_cast< D2&& >( d2 ) );
 
 #ifdef BOOST_NO_EXCEPTIONS
 

include/boost/smart_ptr/detail/sp_counted_impl.hpp

@@ -145,7 +145,7 @@ template<class P, class D> class BOOST_SYMBOL_VISIBLE sp_counted_impl_pd: public
 private:
 
     P ptr; // copy constructor must not throw
-    D del; // copy constructor must not throw
+    D del; // copy/move constructor must not throw
 
     sp_counted_impl_pd( sp_counted_impl_pd const & );
     sp_counted_impl_pd & operator= ( sp_counted_impl_pd const & );
@@ -160,6 +160,14 @@ public:
     {
     }
 
+#if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
+
+    sp_counted_impl_pd( P p, D && d ): ptr( p ), del( static_cast< D&& >( d ) )
+    {
+    }
+
+#endif
+
     sp_counted_impl_pd( P p ): ptr( p ), del()
     {
     }

test/Jamfile

@@ -408,3 +408,5 @@ run wp_unordered_test.cpp ;
 
 run owner_hash_test.cpp ;
 run sp_unordered_test.cpp ;
+
+run sp_unique_ptr_test2.cpp ;

test/sp_unique_ptr_test2.cpp

@@ -0,0 +1,101 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/shared_ptr.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <memory>
+#include <utility>
+
+#if defined( BOOST_NO_CXX11_SMART_PTR )
+
+BOOST_PRAGMA_MESSAGE("Skipping test because BOOST_NO_CXX11_SMART_PTR is defined")
+int main() {}
+
+#elif defined( BOOST_NO_CXX11_RVALUE_REFERENCES )
+
+BOOST_PRAGMA_MESSAGE("Skipping test because BOOST_NO_CXX11_RVALUE_REFERENCES is defined")
+int main() {}
+
+#else
+
+struct Y
+{
+    static int instances;
+
+    bool deleted_;
+
+    Y(): deleted_( false )
+    {
+        ++instances;
+    }
+
+    ~Y()
+    {
+        BOOST_TEST( deleted_ );
+        --instances;
+    }
+
+private:
+
+    Y( Y const & );
+    Y & operator=( Y const & );
+};
+
+int Y::instances = 0;
+
+struct YD
+{
+    bool moved_;
+
+    YD(): moved_( false )
+    {
+    }
+
+    YD( YD&& r ): moved_( false )
+    {
+        r.moved_ = true;
+    }
+
+    void operator()( Y* p ) const
+    {
+        BOOST_TEST( !moved_ );
+
+        if( p )
+        {
+            p->deleted_ = true;
+            delete p;
+        }
+        else
+        {
+            BOOST_ERROR( "YD::operator()(0) called" );
+        }
+    }
+
+private:
+
+    YD( YD const & );
+    YD & operator=( YD const & );
+};
+
+int main()
+{
+    BOOST_TEST( Y::instances == 0 );
+
+    std::unique_ptr<Y, YD> p( new Y );
+    BOOST_TEST( Y::instances == 1 );
+
+    boost::shared_ptr<Y> p2( std::move( p ) );
+    BOOST_TEST( Y::instances == 1 );
+    BOOST_TEST( p.get() == 0 );
+    BOOST_TEST( p.get_deleter().moved_ );
+
+    p2.reset();
+    BOOST_TEST( Y::instances == 0 );
+
+    return boost::report_errors();
+}
+
+#endif