diff --git a/src/ban.h b/src/ban.h
index 35bf10abb..44cc94e6e 100644
--- a/src/ban.h
+++ b/src/ban.h
@@ -30,7 +30,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 class BanManager
 {
 public:
-	BanManager(const std::string &bannfilepath);
+	BanManager(const std::string &banfilepath);
 	~BanManager();
 	void load();
 	void save();
diff --git a/src/camera.cpp b/src/camera.cpp
index 7406aba03..b7aed5d74 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -283,8 +283,7 @@ void Camera::addArmInertia(f32 player_yaw)
 	}
 }
 
-void Camera::update(LocalPlayer* player, f32 frametime, f32 busytime,
-		f32 tool_reload_ratio, ClientEnvironment &c_env)
+void Camera::update(LocalPlayer* player, f32 frametime, f32 busytime, f32 tool_reload_ratio)
 {
 	// Get player position
 	// Smooth the movement when walking up stairs
@@ -408,19 +407,19 @@ void Camera::update(LocalPlayer* player, f32 frametime, f32 busytime,
 
 		// Calculate new position
 		bool abort = false;
-		for (int i = BS; i <= BS*2.75; i++)
-		{
-			my_cp.X = m_camera_position.X + m_camera_direction.X*-i;
-			my_cp.Z = m_camera_position.Z + m_camera_direction.Z*-i;
+		for (int i = BS; i <= BS * 2.75; i++) {
+			my_cp.X = m_camera_position.X + m_camera_direction.X * -i;
+			my_cp.Z = m_camera_position.Z + m_camera_direction.Z * -i;
 			if (i > 12)
-				my_cp.Y = m_camera_position.Y + (m_camera_direction.Y*-i);
+				my_cp.Y = m_camera_position.Y + (m_camera_direction.Y * -i);
 
 			// Prevent camera positioned inside nodes
 			INodeDefManager *nodemgr = m_client->ndef();
-			MapNode n = c_env.getClientMap().getNodeNoEx(floatToInt(my_cp, BS));
+			MapNode n = m_client->getEnv().getClientMap()
+				.getNodeNoEx(floatToInt(my_cp, BS));
+
 			const ContentFeatures& features = nodemgr->get(n);
-			if(features.walkable)
-			{
+			if (features.walkable) {
 				my_cp.X += m_camera_direction.X*-1*-BS/2;
 				my_cp.Z += m_camera_direction.Z*-1*-BS/2;
 				my_cp.Y += m_camera_direction.Y*-1*-BS/2;
diff --git a/src/camera.h b/src/camera.h
index 052284cac..ce80fa9f8 100644
--- a/src/camera.h
+++ b/src/camera.h
@@ -24,13 +24,10 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "inventory.h"
 #include "mesh.h"
 #include "client/tile.h"
-#include "util/numeric.h"
 #include <ICameraSceneNode.h>
 #include <ISceneNode.h>
 #include <list>
 
-#include "client.h"
-
 class LocalPlayer;
 struct MapDrawControl;
 class Client;
@@ -120,7 +117,7 @@ public:
 	// Update the camera from the local player's position.
 	// busytime is used to adjust the viewing range.
 	void update(LocalPlayer* player, f32 frametime, f32 busytime,
-			f32 tool_reload_ratio, ClientEnvironment &c_env);
+			f32 tool_reload_ratio);
 
 	// Update render distance
 	void updateViewingRange();
diff --git a/src/client.cpp b/src/client.cpp
index 402418ea2..dc8e0d4e2 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -22,6 +22,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <sstream>
 #include <cmath>
 #include <IFileSystem.h>
+#include "client.h"
+#include "network/clientopcodes.h"
+#include "network/networkpacket.h"
 #include "threading/mutex_auto_lock.h"
 #include "client/renderingengine.h"
 #include "util/auth.h"
@@ -30,8 +33,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/serialize.h"
 #include "util/string.h"
 #include "util/srp.h"
-#include "client.h"
-#include "network/clientopcodes.h"
 #include "filesys.h"
 #include "mapblock_mesh.h"
 #include "mapblock.h"
diff --git a/src/client.h b/src/client.h
index 05f3ab9ea..121f825b9 100644
--- a/src/client.h
+++ b/src/client.h
@@ -38,7 +38,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "tileanimation.h"
 #include "mesh_generator_thread.h"
 #include <fstream>
-#include "filesys.h"
 
 #define CLIENT_CHAT_MESSAGE_LIMIT_PER_10S 10.0f
 
diff --git a/src/client/inputhandler.h b/src/client/inputhandler.h
index bc8251887..f14e7d801 100644
--- a/src/client/inputhandler.h
+++ b/src/client/inputhandler.h
@@ -247,8 +247,8 @@ public:
 		}
 
 		return m_mousepos;
-
 	}
+
 	virtual void setMousePos(s32 x, s32 y)
 	{
 		if (RenderingEngine::get_raw_device()->getCursorControl()) {
diff --git a/src/client/renderingengine.cpp b/src/client/renderingengine.cpp
index 21af8948a..705871160 100644
--- a/src/client/renderingengine.cpp
+++ b/src/client/renderingengine.cpp
@@ -21,10 +21,12 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <IrrlichtDevice.h>
 #include <irrlicht.h>
 #include "fontengine.h"
+#include "client.h"
 #include "clouds.h"
 #include "util/numeric.h"
 #include "guiscalingfilter.h"
 #include "hud.h"
+#include "localplayer.h"
 #include "camera.h"
 #include "minimap.h"
 #include "clientmap.h"
diff --git a/src/clientenvironment.cpp b/src/clientenvironment.cpp
index 9abb6a23d..c98b5fc90 100644
--- a/src/clientenvironment.cpp
+++ b/src/clientenvironment.cpp
@@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "util/serialize.h"
 #include "util/pointedthing.h"
+#include "client.h"
 #include "clientenvironment.h"
 #include "clientsimpleobject.h"
 #include "clientmap.h"
diff --git a/src/clientenvironment.h b/src/clientenvironment.h
index 070ff95fb..35dca5718 100644
--- a/src/clientenvironment.h
+++ b/src/clientenvironment.h
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <ISceneManager.h>
 #include "environment.h"
 #include "clientobject.h"
+#include "util/numeric.h"
 
 class ClientSimpleObject;
 class ClientMap;
diff --git a/src/clientiface.cpp b/src/clientiface.cpp
index fdabcc783..cdb64e192 100644
--- a/src/clientiface.cpp
+++ b/src/clientiface.cpp
@@ -18,18 +18,17 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include <sstream>
-
 #include "clientiface.h"
+#include "network/connection.h"
+#include "network/serveropcodes.h"
 #include "remoteplayer.h"
 #include "settings.h"
 #include "mapblock.h"
-#include "network/connection.h"
 #include "serverenvironment.h"
 #include "map.h"
 #include "emerge.h"
 #include "content_sao.h"              // TODO this is used for cleanup of only
 #include "log.h"
-#include "network/serveropcodes.h"
 #include "util/srp.h"
 #include "face_position_cache.h"
 
diff --git a/src/clientiface.h b/src/clientiface.h
index ce74cfece..edc389cbb 100644
--- a/src/clientiface.h
+++ b/src/clientiface.h
@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "constants.h"
 #include "serialization.h"             // for SER_FMT_VER_INVALID
 #include "network/networkpacket.h"
+#include "network/networkprotocol.h"
 #include "porting.h"
 
 #include <list>
diff --git a/src/content_cao.cpp b/src/content_cao.cpp
index 771820cb0..90f08f366 100644
--- a/src/content_cao.cpp
+++ b/src/content_cao.cpp
@@ -41,6 +41,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "localplayer.h"
 #include "map.h"
 #include "camera.h" // CameraModes
+#include "client.h"
 #include "wieldmesh.h"
 #include <algorithm>
 #include "client/renderingengine.h"
diff --git a/src/content_mapblock.h b/src/content_mapblock.h
index 51c5fc6ea..d1c8c7caf 100644
--- a/src/content_mapblock.h
+++ b/src/content_mapblock.h
@@ -19,7 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #ifndef CONTENT_MAPBLOCK_HEADER
 #define CONTENT_MAPBLOCK_HEADER
-#include "util/numeric.h"
+
 #include "nodedef.h"
 #include <IMeshManipulator.h>
 
diff --git a/src/environment.h b/src/environment.h
index 1b1cfc50a..6c45592dc 100644
--- a/src/environment.h
+++ b/src/environment.h
@@ -36,9 +36,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <atomic>
 #include <mutex>
 #include "irr_v3d.h"
-#include "activeobject.h"
-#include "util/numeric.h"
 #include "network/networkprotocol.h" // for AccessDeniedCode
+#include "util/basic_macros.h"
 
 class IGameDef;
 class Map;
diff --git a/src/game.cpp b/src/game.cpp
index 4588e21e0..cdbd92301 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -3445,8 +3445,7 @@ void Game::updateCamera(u32 busy_time, f32 dtime)
 	float tool_reload_ratio = runData.time_from_last_punch / full_punch_interval;
 
 	tool_reload_ratio = MYMIN(tool_reload_ratio, 1.0);
-	camera->update(player, dtime, busy_time / 1000.0f, tool_reload_ratio,
-		      client->getEnv());
+	camera->update(player, dtime, busy_time / 1000.0f, tool_reload_ratio);
 	camera->step(dtime);
 
 	v3f camera_position = camera->getPosition();
diff --git a/src/gettext.h b/src/gettext.h
index 885d7ca2d..b87bdd9cc 100644
--- a/src/gettext.h
+++ b/src/gettext.h
@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define GETTEXT_HEADER
 
 #include "config.h" // for USE_GETTEXT
+#include <string>
 
 #if USE_GETTEXT
 	#include <libintl.h>
diff --git a/src/guiKeyChangeMenu.h b/src/guiKeyChangeMenu.h
index 84d3fffcd..84807c79f 100644
--- a/src/guiKeyChangeMenu.h
+++ b/src/guiKeyChangeMenu.h
@@ -24,7 +24,6 @@
 
 #include "irrlichttypes_extrabloated.h"
 #include "modalMenu.h"
-#include "client.h"
 #include "gettext.h"
 #include "keycode.h"
 #include <string>
diff --git a/src/guiPasswordChange.cpp b/src/guiPasswordChange.cpp
index ce1b66fd0..69db4e6b2 100644
--- a/src/guiPasswordChange.cpp
+++ b/src/guiPasswordChange.cpp
@@ -17,9 +17,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
 #include "guiPasswordChange.h"
-#include "debug.h"
-#include "serialization.h"
-#include <string>
+#include "client.h"
 #include <IGUICheckBox.h>
 #include <IGUIEditBox.h>
 #include <IGUIButton.h>
diff --git a/src/guiPasswordChange.h b/src/guiPasswordChange.h
index d9d21e7c4..bb678fe2c 100644
--- a/src/guiPasswordChange.h
+++ b/src/guiPasswordChange.h
@@ -21,9 +21,10 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include "irrlichttypes_extrabloated.h"
 #include "modalMenu.h"
-#include "client.h"
 #include <string>
 
+class Client;
+
 class GUIPasswordChange : public GUIModalMenu
 {
 public:
diff --git a/src/guiVolumeChange.h b/src/guiVolumeChange.h
index 98731c673..0a743dcdb 100644
--- a/src/guiVolumeChange.h
+++ b/src/guiVolumeChange.h
@@ -22,7 +22,6 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include "irrlichttypes_extrabloated.h"
 #include "modalMenu.h"
-#include "client.h"
 #include <string>
 
 class GUIVolumeChange : public GUIModalMenu
@@ -32,7 +31,7 @@ public:
 			gui::IGUIElement* parent, s32 id,
 			IMenuManager *menumgr);
 	~GUIVolumeChange();
-	
+
 	void removeChildren();
 	/*
 		Remove and re-add (or reposition) stuff
@@ -42,7 +41,7 @@ public:
 	void drawMenu();
 
 	bool OnEvent(const SEvent& event);
-	
+
 	bool pausesGame() { return true; }
 };
 
diff --git a/src/irrlichttypes.h b/src/irrlichttypes.h
index dedebd45b..33bfa9ee9 100644
--- a/src/irrlichttypes.h
+++ b/src/irrlichttypes.h
@@ -28,7 +28,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
  *       regardless of the compiler.
  */
 #ifndef _MSC_VER
-#	include <stdint.h>
+#	include <cstdint>
 #endif
 
 #include <irrTypes.h>
diff --git a/src/localplayer.h b/src/localplayer.h
index ffaa83f33..5c52a9c0e 100644
--- a/src/localplayer.h
+++ b/src/localplayer.h
@@ -144,7 +144,9 @@ public:
 	void setCollisionbox(const aabb3f &box) { m_collisionbox = box; }
 
 private:
+	// clang-format off
 	void accelerateHorizontal(const v3f &target_speed, f32 max_increase, bool slippery);
+	// clang-format on
 	void accelerateVertical(const v3f &target_speed, const f32 max_increase);
 	bool updateSneakNode(Map *map, const v3f &position, const v3f &sneak_max);
 
diff --git a/src/main.cpp b/src/main.cpp
index b9530c55e..ee391cf68 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "mainmenumanager.h"
 #include "irrlichttypes_extrabloated.h"
+#include "chat_interface.h"
 #include "debug.h"
 #include "unittest/test.h"
 #include "server.h"
@@ -34,10 +35,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "quicktune.h"
 #include "httpfetch.h"
 #include "guiEngine.h"
-#include "map.h"
-#include "player.h"
-#include "mapsector.h"
-#include "fontengine.h"
 #include "gameparams.h"
 #include "database.h"
 #include "config.h"
@@ -47,7 +44,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #endif
 #ifndef SERVER
 #include "client/clientlauncher.h"
-
 #endif
 
 #ifdef HAVE_TOUCHSCREENGUI
diff --git a/src/mapblock_mesh.cpp b/src/mapblock_mesh.cpp
index 67195cab3..5ab96a156 100644
--- a/src/mapblock_mesh.cpp
+++ b/src/mapblock_mesh.cpp
@@ -18,6 +18,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "mapblock_mesh.h"
+#include "client.h"
 #include "mapblock.h"
 #include "map.h"
 #include "profiler.h"
diff --git a/src/mg_ore.cpp b/src/mg_ore.cpp
index 36100f762..044d58db8 100644
--- a/src/mg_ore.cpp
+++ b/src/mg_ore.cpp
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "noise.h"
 #include "map.h"
 #include "log.h"
+#include "util/numeric.h"
 #include <algorithm>
 
 
diff --git a/src/minimap.cpp b/src/minimap.cpp
index 71a4c9c67..dab5f3aa5 100644
--- a/src/minimap.cpp
+++ b/src/minimap.cpp
@@ -18,16 +18,10 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "minimap.h"
-#include "threading/mutex_auto_lock.h"
-#include "threading/semaphore.h"
+#include "client.h"
 #include "clientmap.h"
 #include "settings.h"
-#include "nodedef.h"
-#include "porting.h"
-#include "util/numeric.h"
-#include "util/string.h"
 #include "mapblock.h"
-#include <math.h>
 #include "client/renderingengine.h"
 
 
@@ -37,16 +31,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 MinimapUpdateThread::~MinimapUpdateThread()
 {
-	for (std::map<v3s16, MinimapMapblock *>::iterator
-			it = m_blocks_cache.begin();
-			it != m_blocks_cache.end(); ++it) {
-		delete it->second;
+	for (auto &it : m_blocks_cache) {
+		delete it.second;
 	}
 
-	for (std::deque<QueuedMinimapUpdate>::iterator
-			it = m_update_queue.begin();
-			it != m_update_queue.end(); ++it) {
-		QueuedMinimapUpdate &q = *it;
+	for (auto &q : m_update_queue) {
 		delete q.data;
 	}
 }
diff --git a/src/minimap.h b/src/minimap.h
index 01eafbe59..f087dbfab 100644
--- a/src/minimap.h
+++ b/src/minimap.h
@@ -21,18 +21,19 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define MINIMAP_HEADER
 
 #include "irrlichttypes_extrabloated.h"
-#include "client.h"
+#include "util/thread.h"
 #include "voxel.h"
-#include "threading/semaphore.h"
 #include <map>
 #include <string>
 #include <vector>
-#include "camera.h"
+
+class Client;
+class ITextureSource;
+class IShaderSource;
 
 #define MINIMAP_MAX_SX 512
 #define MINIMAP_MAX_SY 512
 
-
 enum MinimapMode {
 	MINIMAP_MODE_OFF,
 	MINIMAP_MODE_SURFACEx1,
diff --git a/src/network/clientopcodes.h b/src/network/clientopcodes.h
index 43a93bb4f..789c9c0bb 100644
--- a/src/network/clientopcodes.h
+++ b/src/network/clientopcodes.h
@@ -23,7 +23,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "client.h"
 #include "networkprotocol.h"
-#include "networkpacket.h"
+
+class NetworkPacket;
 
 enum ToClientConnectionState {
 	TOCLIENT_STATE_NOT_CONNECTED,
diff --git a/src/network/connection.cpp b/src/network/connection.cpp
index d1ab948db..c93971cac 100644
--- a/src/network/connection.cpp
+++ b/src/network/connection.cpp
@@ -563,6 +563,20 @@ void IncomingSplitBuffer::removeUnreliableTimedOuts(float dtime, float timeout)
 	}
 }
 
+/*
+	ConnectionCommand
+ */
+
+void ConnectionCommand::send(u16 peer_id_, u8 channelnum_, NetworkPacket *pkt,
+	bool reliable_)
+{
+	type = CONNCMD_SEND;
+	peer_id = peer_id_;
+	channelnum = channelnum_;
+	data = pkt->oldForgePacket();
+	reliable = reliable_;
+}
+
 /*
 	Channel
 */
diff --git a/src/network/connection.h b/src/network/connection.h
index 289c79125..3dc87b489 100644
--- a/src/network/connection.h
+++ b/src/network/connection.h
@@ -24,7 +24,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "socket.h"
 #include "exceptions.h"
 #include "constants.h"
-#include "network/networkpacket.h"
 #include "util/pointer.h"
 #include "util/container.h"
 #include "util/thread.h"
@@ -433,15 +432,8 @@ struct ConnectionCommand
 		type = CONNCMD_DISCONNECT_PEER;
 		peer_id = peer_id_;
 	}
-	void send(u16 peer_id_, u8 channelnum_,
-			NetworkPacket* pkt, bool reliable_)
-	{
-		type = CONNCMD_SEND;
-		peer_id = peer_id_;
-		channelnum = channelnum_;
-		data = pkt->oldForgePacket();
-		reliable = reliable_;
-	}
+
+	void send(u16 peer_id_, u8 channelnum_, NetworkPacket* pkt, bool reliable_);
 
 	void ack(u16 peer_id_, u8 channelnum_, const SharedBuffer<u8> &data_)
 	{
diff --git a/src/network/networkpacket.cpp b/src/network/networkpacket.cpp
index 78c73d253..ab7ddfb57 100644
--- a/src/network/networkpacket.cpp
+++ b/src/network/networkpacket.cpp
@@ -18,7 +18,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "networkpacket.h"
-#include "debug.h"
+#include <sstream>
 #include "exceptions.h"
 #include "util/serialize.h"
 
diff --git a/src/network/networkpacket.h b/src/network/networkpacket.h
index 7eb8cc3ff..40a20eb2e 100644
--- a/src/network/networkpacket.h
+++ b/src/network/networkpacket.h
@@ -20,9 +20,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef NETWORKPACKET_HEADER
 #define NETWORKPACKET_HEADER
 
+#include <SColor.h>
 #include "util/pointer.h"
 #include "util/numeric.h"
-#include "networkprotocol.h"
 
 class NetworkPacket
 {
diff --git a/src/network/serveropcodes.h b/src/network/serveropcodes.h
index 72323ae24..296b7d471 100644
--- a/src/network/serveropcodes.h
+++ b/src/network/serveropcodes.h
@@ -23,7 +23,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "server.h"
 #include "networkprotocol.h"
-#include "networkpacket.h"
+
+class NetworkPacket;
 
 enum ToServerConnectionState {
 	TOSERVER_STATE_NOT_CONNECTED,
diff --git a/src/nodedef.h b/src/nodedef.h
index 66296016a..6ae729409 100644
--- a/src/nodedef.h
+++ b/src/nodedef.h
@@ -25,7 +25,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <iostream>
 #include <map>
 #include <list>
-#include "util/numeric.h"
 #include "mapnode.h"
 #ifndef SERVER
 #include "client/tile.h"
diff --git a/src/noise.h b/src/noise.h
index d5aca4def..53cab5754 100644
--- a/src/noise.h
+++ b/src/noise.h
@@ -111,7 +111,7 @@ struct NoiseParams {
 	float lacunarity = 2.0f;
 	u32 flags = NOISE_FLAG_DEFAULTS;
 
-	NoiseParams() {}
+	NoiseParams() = default;
 
 	NoiseParams(float offset_, float scale_, v3f spread_, s32 seed_,
 		u16 octaves_, float persist_, float lacunarity_,
diff --git a/src/script/cpp_api/s_async.h b/src/script/cpp_api/s_async.h
index 94b55db6e..aa1559ed1 100644
--- a/src/script/cpp_api/s_async.h
+++ b/src/script/cpp_api/s_async.h
@@ -24,8 +24,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <deque>
 #include <map>
 
-#include "threading/thread.h"
 #include "threading/semaphore.h"
+#include "threading/thread.h"
 #include "debug.h"
 #include "lua.h"
 #include "cpp_api/s_base.h"
@@ -39,7 +39,7 @@ class AsyncEngine;
 // Data required to queue a job
 struct LuaJobInfo
 {
-	LuaJobInfo() {};
+	LuaJobInfo() = default;
 
 	// Function to be called in async environment
 	std::string serializedFunction = "";
diff --git a/src/script/cpp_api/s_base.h b/src/script/cpp_api/s_base.h
index 28fefdd37..ff92bdf93 100644
--- a/src/script/cpp_api/s_base.h
+++ b/src/script/cpp_api/s_base.h
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <iostream>
 #include <string>
 #include <thread>
+#include <mutex>
 #include "util/basic_macros.h"
 
 extern "C" {
@@ -30,7 +31,6 @@ extern "C" {
 }
 
 #include "irrlichttypes.h"
-#include "threading/mutex_auto_lock.h"
 #include "common/c_types.h"
 #include "common/c_internal.h"
 
diff --git a/src/script/cpp_api/s_internal.h b/src/script/cpp_api/s_internal.h
index 315561e08..b493cb6fa 100644
--- a/src/script/cpp_api/s_internal.h
+++ b/src/script/cpp_api/s_internal.h
@@ -30,6 +30,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <thread>
 #include "common/c_internal.h"
 #include "cpp_api/s_base.h"
+#include "threading/mutex_auto_lock.h"
 
 #ifdef SCRIPTAPI_LOCK_DEBUG
 #include "debug.h" // assert()
diff --git a/src/script/lua_api/l_base.h b/src/script/lua_api/l_base.h
index af89afd93..e9b28b36a 100644
--- a/src/script/lua_api/l_base.h
+++ b/src/script/lua_api/l_base.h
@@ -30,7 +30,7 @@ extern "C" {
 }
 
 #ifndef SERVER
-#include "client.h"
+class Client;
 #endif
 
 class ScriptApiBase;
diff --git a/src/script/lua_api/l_camera.cpp b/src/script/lua_api/l_camera.cpp
index ef842a222..49622df00 100644
--- a/src/script/lua_api/l_camera.cpp
+++ b/src/script/lua_api/l_camera.cpp
@@ -3,6 +3,7 @@
 #include "l_internal.h"
 #include "content_cao.h"
 #include "camera.h"
+#include "client.h"
 
 LuaCamera::LuaCamera(Camera *m) : m_camera(m)
 {
diff --git a/src/script/lua_api/l_client.cpp b/src/script/lua_api/l_client.cpp
index 6f9240466..81dfdb1e9 100644
--- a/src/script/lua_api/l_client.cpp
+++ b/src/script/lua_api/l_client.cpp
@@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "l_client.h"
 #include "chatmessage.h"
+#include "client.h"
 #include "clientenvironment.h"
 #include "common/c_content.h"
 #include "common/c_converter.h"
diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index 2a57ca59b..9a2ce334b 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -37,6 +37,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "emerge.h"
 #include "pathfinder.h"
 #include "face_position_cache.h"
+#ifndef SERVER
+#include "client.h"
+#endif
 
 struct EnumString ModApiEnvMod::es_ClearObjectsMode[] =
 {
diff --git a/src/script/lua_api/l_localplayer.cpp b/src/script/lua_api/l_localplayer.cpp
index 7f932cbca..da560c3ac 100644
--- a/src/script/lua_api/l_localplayer.cpp
+++ b/src/script/lua_api/l_localplayer.cpp
@@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "l_localplayer.h"
 #include "l_internal.h"
 #include "script/common/c_converter.h"
+#include "localplayer.h"
 
 LuaLocalPlayer::LuaLocalPlayer(LocalPlayer *m) : m_localplayer(m)
 {
diff --git a/src/script/lua_api/l_minimap.cpp b/src/script/lua_api/l_minimap.cpp
index be981c884..b59e79095 100644
--- a/src/script/lua_api/l_minimap.cpp
+++ b/src/script/lua_api/l_minimap.cpp
@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_minimap.h"
 #include "lua_api/l_internal.h"
 #include "common/c_converter.h"
+#include "client.h"
 #include "minimap.h"
 #include "settings.h"
 
diff --git a/src/server.cpp b/src/server.cpp
index 4ccac5748..41493a862 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -61,6 +61,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/hex.h"
 #include "database.h"
 #include "chatmessage.h"
+#include "chat_interface.h"
 
 class ClientNotFoundException : public BaseException
 {
diff --git a/src/server.h b/src/server.h
index ac7ba4f61..aae589f9a 100644
--- a/src/server.h
+++ b/src/server.h
@@ -34,16 +34,17 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/thread.h"
 #include "util/basic_macros.h"
 #include "serverenvironment.h"
-#include "chat_interface.h"
 #include "clientiface.h"
 #include "remoteplayer.h"
-#include "network/networkpacket.h"
 #include "chatmessage.h"
 #include <string>
 #include <list>
 #include <map>
 #include <vector>
 
+class ChatEvent;
+struct ChatEventChat;
+struct ChatInterface;
 class IWritableItemDefManager;
 class IWritableNodeDefManager;
 class IWritableCraftDefManager;
diff --git a/src/serverenvironment.h b/src/serverenvironment.h
index 4cfe7f7d6..c9f80a4c4 100644
--- a/src/serverenvironment.h
+++ b/src/serverenvironment.h
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "environment.h"
 #include "mapnode.h"
 #include "mapblock.h"
+#include "activeobject.h"
 #include <set>
 
 class IGameDef;
diff --git a/src/terminal_chat_console.cpp b/src/terminal_chat_console.cpp
index a8c4ebaef..222c08646 100644
--- a/src/terminal_chat_console.cpp
+++ b/src/terminal_chat_console.cpp
@@ -25,6 +25,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "settings.h"
 #include "util/numeric.h"
 #include "util/string.h"
+#include "chat_interface.h"
 
 TerminalChatConsole g_term_console;
 
diff --git a/src/terminal_chat_console.h b/src/terminal_chat_console.h
index 8f6abe295..b656f8872 100644
--- a/src/terminal_chat_console.h
+++ b/src/terminal_chat_console.h
@@ -22,11 +22,13 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "chat.h"
 #include "threading/thread.h"
-#include "chat_interface.h"
+#include "util/container.h"
 #include "log.h"
-
 #include <sstream>
 
+
+struct ChatInterface;
+
 class TermLogOutput : public ILogOutput {
 public:
 
diff --git a/src/unittest/test.cpp b/src/unittest/test.cpp
index 911b647f7..b52189cb4 100644
--- a/src/unittest/test.cpp
+++ b/src/unittest/test.cpp
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "itemdef.h"
 #include "gamedef.h"
 #include "mods.h"
+#include "util/numeric.h"
 
 content_t t_CONTENT_STONE;
 content_t t_CONTENT_GRASS;
diff --git a/src/unittest/test_connection.cpp b/src/unittest/test_connection.cpp
index 3ea3d7444..c23d2a068 100644
--- a/src/unittest/test_connection.cpp
+++ b/src/unittest/test_connection.cpp
@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "settings.h"
 #include "util/serialize.h"
 #include "network/connection.h"
+#include "network/networkpacket.h"
 
 class TestConnection : public TestBase {
 public: