diff --git a/include/libtorrent/alert_types.hpp b/include/libtorrent/alert_types.hpp
index 1c52d9471..4dfc48b6c 100644
--- a/include/libtorrent/alert_types.hpp
+++ b/include/libtorrent/alert_types.hpp
@@ -2675,7 +2675,7 @@ TORRENT_VERSION_NAMESPACE_2
 		// internal
 		picker_log_alert(aux::stack_allocator& alloc, torrent_handle const& h
 			, tcp::endpoint const& ep, peer_id const& peer_id, picker_flags_t flags
-			, piece_block const* blocks, int num_blocks);
+			, span<piece_block const> blocks);
 
 		TORRENT_DEFINE_ALERT(picker_log_alert, 89)
 
diff --git a/src/alert.cpp b/src/alert.cpp
index 3934339ef..797177899 100644
--- a/src/alert.cpp
+++ b/src/alert.cpp
@@ -2220,12 +2220,12 @@ namespace {
 
 	picker_log_alert::picker_log_alert(aux::stack_allocator& alloc, torrent_handle const& h
 		, tcp::endpoint const& ep, peer_id const& peer_id, picker_flags_t const flags
-		, piece_block const* blocks, int num_blocks)
+		, span<piece_block const> blocks)
 		: peer_alert(alloc, h, ep, peer_id)
 		, picker_flags(flags)
-		, m_array_idx(alloc.copy_buffer({reinterpret_cast<char const*>(blocks)
-			, aux::numeric_cast<std::size_t>(num_blocks) * sizeof(piece_block)}))
-		, m_num_blocks(num_blocks)
+		, m_array_idx(alloc.copy_buffer({reinterpret_cast<char const*>(blocks.data())
+			, blocks.size() * int(sizeof(piece_block))}))
+		, m_num_blocks(int(blocks.size()))
 	{}
 
 	std::vector<piece_block> picker_log_alert::blocks() const
diff --git a/src/request_blocks.cpp b/src/request_blocks.cpp
index eda95362a..65f6611f8 100644
--- a/src/request_blocks.cpp
+++ b/src/request_blocks.cpp
@@ -175,7 +175,7 @@ namespace libtorrent {
 			&& !interesting_pieces.empty())
 		{
 			t.alerts().emplace_alert<picker_log_alert>(t.get_handle(), c.remote()
-				, c.pid(), flags, &interesting_pieces[0], int(interesting_pieces.size()));
+				, c.pid(), flags, interesting_pieces);
 		}
 		c.peer_log(peer_log_alert::info, "PIECE_PICKER"
 			, "prefer_contiguous: %d picked: %d"