fix GCC-9 warnings

include/libtorrent/aux_/disable_warnings_push.hpp

@@ -55,6 +55,9 @@ POSSIBILITY OF SUCH DAMAGE.
 #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
 #pragma GCC diagnostic ignored "-Wnoexcept-type"
 #endif
+#if __GNUC__ >= 9
+#pragma GCC diagnostic ignored "-Wdeprecated-copy"
+#endif
 #endif
 
 #ifdef __clang__

src/kademlia/find_data.cpp

@@ -127,7 +127,7 @@ observer_ptr find_data::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 	if (o) o->m_in_constructor = false;
 #endif
-	return std::move(o);
+	return o;
 }
 
 char const* find_data::name() const { return "find_data"; }

src/kademlia/get_item.cpp

@@ -127,7 +127,7 @@ observer_ptr get_item::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 	if (o) o->m_in_constructor = false;
 #endif
-	return std::move(o);
+	return o;
 }
 
 bool get_item::invoke(observer_ptr o)

src/kademlia/get_peers.cpp

@@ -157,7 +157,7 @@ observer_ptr get_peers::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 	if (o) o->m_in_constructor = false;
 #endif
-	return std::move(o);
+	return o;
 }
 
 obfuscated_get_peers::obfuscated_get_peers(
@@ -184,7 +184,7 @@ observer_ptr obfuscated_get_peers::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 		if (o) o->m_in_constructor = false;
 #endif
-		return std::move(o);
+		return o;
 	}
 	else
 	{
@@ -193,7 +193,7 @@ observer_ptr obfuscated_get_peers::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 		if (o) o->m_in_constructor = false;
 #endif
-		return std::move(o);
+		return o;
 	}
 }
 

src/kademlia/refresh.cpp

@@ -44,7 +44,7 @@ observer_ptr bootstrap::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 	if (o) o->m_in_constructor = false;
 #endif
-	return std::move(o);
+	return o;
 }
 
 bool bootstrap::invoke(observer_ptr o)

src/kademlia/traversal_algorithm.cpp

@@ -77,7 +77,7 @@ observer_ptr traversal_algorithm::new_observer(udp::endpoint const& ep
 #if TORRENT_USE_ASSERTS
 	if (o) o->m_in_constructor = false;
 #endif
-	return std::move(o);
+	return o;
 }
 
 traversal_algorithm::traversal_algorithm(node& dht_node, node_id const& target)

src/ut_pex.cpp

@@ -628,7 +628,7 @@ namespace libtorrent { namespace {
 		bt_peer_connection* c = static_cast<bt_peer_connection*>(pc.native_handle().get());
 		auto p = std::make_shared<ut_pex_peer_plugin>(m_torrent, *c, *this);
 		c->set_ut_pex(p);
-		return std::move(p);
+		return p;
 	}
 } }