diff --git a/library/include/PluginManager.h b/library/include/PluginManager.h
index 726734baa..d14f4d99a 100644
--- a/library/include/PluginManager.h
+++ b/library/include/PluginManager.h
@@ -43,7 +43,7 @@ namespace DFHack
 {
     class Core;
     class PluginManager;
-    struct virtual_identity;
+    class virtual_identity;
 
     enum command_result
     {