diff --git a/src/mg_decoration.h b/src/mg_decoration.h
index c698710b53..3262924b02 100644
--- a/src/mg_decoration.h
+++ b/src/mg_decoration.h
@@ -23,7 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <set>
 #include "mapgen.h"
 
-class NoiseParams;
+struct NoiseParams;
 class Mapgen;
 class ManualMapVoxelManipulator;
 class PseudoRandom;
diff --git a/src/mg_ore.h b/src/mg_ore.h
index 4bf415734a..16fb50cd54 100644
--- a/src/mg_ore.h
+++ b/src/mg_ore.h
@@ -23,7 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/string.h"
 #include "mapgen.h"
 
-class NoiseParams;
+struct NoiseParams;
 class Noise;
 class Mapgen;
 class ManualMapVoxelManipulator;
diff --git a/src/rollback.h b/src/rollback.h
index 2e6955c8d4..c57e38ab0b 100644
--- a/src/rollback.h
+++ b/src/rollback.h
@@ -29,8 +29,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 class IGameDef;
 
-class ActionRow;
-class Entity;
+struct ActionRow;
+struct Entity;
 
 class RollbackManager: public IRollbackManager
 {
diff --git a/src/server.h b/src/server.h
index 4292892c50..e9cf0a25c9 100644
--- a/src/server.h
+++ b/src/server.h
@@ -49,7 +49,7 @@ class Inventory;
 class Player;
 class PlayerSAO;
 class IRollbackManager;
-class RollbackAction;
+struct RollbackAction;
 class EmergeManager;
 class GameScripting;
 class ServerEnvironment;
diff --git a/src/wieldmesh.h b/src/wieldmesh.h
index 3b39dbfac3..b7739f18c0 100644
--- a/src/wieldmesh.h
+++ b/src/wieldmesh.h
@@ -23,7 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "irrlichttypes_extrabloated.h"
 #include <string>
 
-class ItemStack;
+struct ItemStack;
 class IGameDef;
 class ITextureSource;
 struct TileSpec;