diff --git a/ebos/eclactionhandler.hh b/ebos/eclactionhandler.hh
index f111e0d84..06ff76a52 100644
--- a/ebos/eclactionhandler.hh
+++ b/ebos/eclactionhandler.hh
@@ -41,7 +41,7 @@ class State;
 class BlackoilWellModelGeneric;
 class EclipseState;
 class Schedule;
-class SimulatorUpdate;
+struct SimulatorUpdate;
 class SummaryState;
 
 //! \brief Class handling Action support in simulator
diff --git a/opm/simulators/linalg/setupPropertyTree.hpp b/opm/simulators/linalg/setupPropertyTree.hpp
index 6c92db417..7fe785c68 100644
--- a/opm/simulators/linalg/setupPropertyTree.hpp
+++ b/opm/simulators/linalg/setupPropertyTree.hpp
@@ -27,7 +27,7 @@
 namespace Opm
 {
 
-class FlowLinearSolverParameters;
+struct FlowLinearSolverParameters;
 
 PropertyTree setupPropertyTree(FlowLinearSolverParameters p,
                                bool LinearSolverMaxIterSet,