diff --git a/opm/parser/eclipse/EclipseState/Schedule/Well/WListManager.hpp b/opm/parser/eclipse/EclipseState/Schedule/Well/WListManager.hpp
index d092ad842..5cb626a68 100644
--- a/opm/parser/eclipse/EclipseState/Schedule/Well/WListManager.hpp
+++ b/opm/parser/eclipse/EclipseState/Schedule/Well/WListManager.hpp
@@ -28,7 +28,7 @@
 namespace Opm {
 
 namespace RestartIO {
-class RstState;
+struct RstState;
 }
 
 class WListManager {