diff --git a/libraries/chain/db_block.cpp b/libraries/chain/db_block.cpp
index e141cd08..2e511591 100644
--- a/libraries/chain/db_block.cpp
+++ b/libraries/chain/db_block.cpp
@@ -36,6 +36,8 @@
 #include <graphene/chain/exceptions.hpp>
 #include <graphene/chain/evaluator.hpp>
 
+#include <fc/smart_ref_impl.hpp>
+
 namespace graphene { namespace chain {
 
 bool database::is_known_block( const block_id_type& id )const