Remove lots of useless/misplaced includes (#7999)

Follow-Up of 7db3fa94a1 .

This was done by setting `CMAKE_C_INCLUDE_WHAT_YOU_USE` and
`CMAKE_CXX_INCLUDE_WHAT_YOU_USE` to (broken down into multiple lines here,
note, all below `FL/x.h` is not required for C):

```
include-what-you-use;
    -Xiwyu;--mapping_file=/usr/share/include-what-you-use/qt5_11.imp;
    -Xiwyu;--keep=*/xmmintrin.h;
    -Xiwyu;--keep=*/lmmsconfig.h;
    -Xiwyu;--keep=*/weak_libjack.h;
    -Xiwyu;--keep=*/sys/*;
    -Xiwyu;--keep=*/debug.h;
    -Xiwyu;--keep=*/SDL/*;
    -Xiwyu;--keep=*/alsa/*;
    -Xiwyu;--keep=*/FL/x.h;
    -Xiwyu;--keep=*/MidiApple.h;
    -Xiwyu;--keep=*/MidiWinMM.h;
    -Xiwyu;--keep=*/AudioSoundIo.h;
    -Xiwyu;--keep=*/OpulenZ/adplug/*;
    -Xiwyu;--keep=QPainterPath;
    -Xiwyu;--keep=QtTest
```

FAQ:

* Q: Does this speed-up a completely fresh compile?
* A: No, I measured it.

* Q: Does it speed up anything else?
* A: Yes. If you change one header, it can reduce the number of CPP files
     that your compiler needs to recompile, or your IDE has to re-scan.

* Q: What other reasons are for this PR?
* A: It's idiomatic to only include headers if you need them. Also, it will
     reduce output for those who want to use IWYU for new PRs.

Background:

This is just a remainder PR of what I planned. My original idea was to setup
a CI which warns you of useless includes (but not of all issues that IWYU
complains about). However, I could not see that this was favored on Discord.
A full IWYU CI also has the problem that it (possibly??) needs to compile
with `make -j 1`, which would make CI really slow.

However, for that plan, I had to fix the whole code base to be IWYU
compliant - which it now is.

include/AudioEngine.h

@@ -45,9 +45,8 @@
 namespace lmms
 {
 
-class AudioDevice;
 class MidiClient;
-class AudioBusHandle;
+class AudioBusHandle;  // IWYU pragma: keep
 class AudioEngineWorkerThread;
 
 constexpr fpp_t MINIMUM_BUFFER_SIZE = 32;

include/AudioPortAudio.h

@@ -69,7 +69,6 @@ public:
 namespace gui
 {
 class ComboBox;
-class LcdSpinBox;
 }
 
 

include/AudioSoundIo.h

@@ -25,10 +25,9 @@
 #ifndef LMMS_AUDIO_SOUNDIO_H
 #define LMMS_AUDIO_SOUNDIO_H
 
-#include <QObject>
 
 #include "lmmsconfig.h"
-#include "ComboBoxModel.h"
+#include "ComboBoxModel.h"  // IWYU pragma: keep
 
 #ifdef LMMS_HAVE_SOUNDIO
 

include/AutomatableButton.h

@@ -1,5 +1,5 @@
 /*
- * AutomatableButton.h - class automatableButton, the base for all buttons
+ * AutomatableButton.h - class AutomatableButton, the base for all buttons
  *
  * Copyright (c) 2006-2008 Tobias Doerffel <tobydox/at/users.sourceforge.net>
  *
@@ -32,7 +32,7 @@
 namespace lmms::gui
 {
 
-class automatableButtonGroup;
+class AutomatableButtonGroup;
 
 
 class LMMS_EXPORT AutomatableButton : public QPushButton, public BoolModelView
@@ -69,10 +69,10 @@ protected:
 
 
 private:
-	automatableButtonGroup * m_group;
+	AutomatableButtonGroup * m_group;
 
 
-	friend class automatableButtonGroup;
+	friend class AutomatableButtonGroup;
 
 	using QPushButton::setChecked;
 	using QPushButton::isChecked;
@@ -80,13 +80,13 @@ private:
 
 
 
-class LMMS_EXPORT automatableButtonGroup : public QWidget, public IntModelView
+class LMMS_EXPORT AutomatableButtonGroup : public QWidget, public IntModelView
 {
 	Q_OBJECT
 public:
-	automatableButtonGroup( QWidget * _parent, const QString & _name
+	AutomatableButtonGroup( QWidget * _parent, const QString & _name
 			= QString() );
-	~automatableButtonGroup() override;
+	~AutomatableButtonGroup() override;
 
 	void addButton( AutomatableButton * _btn );
 	void removeButton( AutomatableButton * _btn );

include/AutomatableModel.h

@@ -28,7 +28,6 @@
 #include <cmath>
 #include <QMap>
 #include <QMutex>
-#include <QRegularExpression>
 
 #include "JournallingObject.h"
 #include "Model.h"

include/AutomationClip.h

@@ -29,9 +29,6 @@
 
 #include <QMap>
 #include <QPointer>
-#if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
-	#include <QRecursiveMutex>
-#endif
 
 #include "AutomationNode.h"
 #include "Clip.h"

include/AutomationEditor.h

@@ -26,7 +26,6 @@
 #ifndef LMMS_GUI_AUTOMATION_EDITOR_H
 #define LMMS_GUI_AUTOMATION_EDITOR_H
 
-#include <QPushButton>
 #include <QWidget>
 #include <array>
 
@@ -34,26 +33,24 @@
 #include "ComboBoxModel.h"
 #include "Editor.h"
 #include "JournallingObject.h"
-#include "MidiClip.h"
 #include "SampleClip.h"
 #include "TimePos.h"
 #include "LmmsTypes.h"
 #include "SampleThumbnail.h"
 
-class QPainter;
-class QPixmap;
+class QPushButton;
 class QScrollBar;
 
 namespace lmms
 {
 
-class NotePlayHandle;
+class MidiClip;
 
 namespace gui
 {
 
-class Knob;
 class ComboBox;
+class Knob;
 class TimeLineWidget;
 
 

include/Clip.h

@@ -36,7 +36,6 @@ namespace lmms
 {
 
 class Track;
-class TrackContainer;
 
 namespace gui
 {

include/ClipView.h

@@ -35,13 +35,11 @@
 
 
 class QMenu;
-class QContextMenuEvent;
 
 namespace lmms
 {
 
 class DataFile;
-class Clip;
 
 namespace gui
 {

include/ConfigManager.h

@@ -40,8 +40,6 @@ namespace lmms
 {
 
 
-class Engine;
-
 const QString PROJECTS_PATH = "projects/";
 const QString TEMPLATE_PATH = "templates/";
 const QString PRESETS_PATH = "presets/";

include/ControlLayout.h

@@ -78,8 +78,6 @@
 #include <QStyle>
 
 class QLayoutItem;
-class QRect;
-class QString;
 class QLineEdit;
 
 

include/ControllerRackView.h

@@ -26,7 +26,6 @@
 #define LMMS_GUI_CONTROLLER_RACK_VIEW_H
 
 #include <QWidget>
-#include <QCloseEvent>
 
 #include "SerializingObject.h"
 

include/Controls.h

@@ -37,8 +37,6 @@ class QLabel;
 namespace lmms
 {
 
-class AutomatableModel;
-
 namespace gui
 {
 

include/EffectRackView.h

@@ -32,7 +32,6 @@
 #include "ModelView.h"
 
 class QScrollArea;
-class QVBoxLayout;
 
 namespace lmms::gui
 {

include/EffectSelectDialog.h

@@ -29,15 +29,13 @@
 #include "Effect.h"
 
 #include <QDialog>
-#include <QHeaderView>
-#include <QKeyEvent>
-#include <QMouseEvent>
-#include <QPushButton>
 #include <QRegularExpression>
-#include <QScrollArea>
 #include <QSortFilterProxyModel>
 #include <QStandardItemModel>
-#include <QTableView>
+
+class QScrollArea;
+class QTableView;
+class QLineEdit;
 
 namespace lmms::gui
 {

include/EnvelopeAndLfoParameters.h

@@ -26,7 +26,6 @@
 #define LMMS_ENVELOPE_AND_LFO_PARAMETERS_H
 
 #include <memory>
-#include <vector>
 
 #include "JournallingObject.h"
 #include "AutomatableModel.h"

include/EnvelopeAndLfoView.h

@@ -38,7 +38,7 @@ class EnvelopeAndLfoParameters;
 namespace gui
 {
 
-class automatableButtonGroup;
+class AutomatableButtonGroup;
 class Knob;
 class LedCheckBox;
 class PixmapButton;
@@ -87,7 +87,7 @@ private:
 	TempoSyncKnob * m_lfoSpeedKnob;
 	Knob * m_lfoAmountKnob;
 	PixmapButton * m_userLfoBtn;
-	automatableButtonGroup * m_lfoWaveBtnGrp;
+	AutomatableButtonGroup * m_lfoWaveBtnGrp;
 
 	LedCheckBox * m_x100Cb;
 	LedCheckBox * m_controlEnvAmountCb;

include/FileBrowser.h

@@ -25,28 +25,25 @@
 #ifndef LMMS_GUI_FILE_BROWSER_H
 #define LMMS_GUI_FILE_BROWSER_H
 
-#include <QCheckBox>
 #include <QDir>
 #include <QMutex>
-#include <QProgressBar>
 #include <memory>
 
-#include "FileSearch.h"
 #include "embed.h"
 
-#if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
-	#include <QRecursiveMutex>
-#endif
 #include <QTreeWidget>
 
 #include "SideBarWidget.h"
 #include "lmmsconfig.h"
 
+class QCheckBox;
 class QLineEdit;
+class QProgressBar;
 
 namespace lmms
 {
 
+class FileSearch;
 class InstrumentTrack;
 class PlayHandle;
 class TrackContainer;
@@ -54,8 +51,8 @@ class TrackContainer;
 namespace gui
 {
 
-class FileItem;
 class FileBrowserTreeWidget;
+class FileItem;
 
 class FileBrowser : public SideBarWidget
 {

include/GuiApplication.h

@@ -26,12 +26,12 @@
 #define LMMS_GUI_GUI_APPLICATION_H
 
 #include <QObject>
-#include <QSocketNotifier>
 
 #include "lmms_export.h"
 #include "lmmsconfig.h"
 
 class QLabel;
+class QSocketNotifier;
 
 namespace lmms::gui
 {

include/InstrumentFunctions.h

@@ -35,7 +35,7 @@
 namespace lmms
 {
 
-class InstrumentTrack;
+class InstrumentTrack;  // IWYU pragma: keep
 class NotePlayHandle;
 
 namespace gui

include/InstrumentSoundShapingView.h

@@ -27,11 +27,12 @@
 
 #include <QWidget>
 
-#include "InstrumentSoundShaping.h"
 #include "ModelView.h"
 
 class QLabel;
 
+namespace lmms { class InstrumentSoundShaping; }
+
 namespace lmms::gui
 {
 

include/InstrumentTrack.h

@@ -26,7 +26,6 @@
 #ifndef LMMS_INSTRUMENT_TRACK_H
 #define LMMS_INSTRUMENT_TRACK_H
 
-#include <limits>
 
 #include "AudioBusHandle.h"
 #include "InstrumentFunctions.h"

include/InstrumentTrackView.h

@@ -25,7 +25,6 @@
 #ifndef LMMS_GUI_INSTRUMENT_TRACK_VIEW_H
 #define LMMS_GUI_INSTRUMENT_TRACK_VIEW_H
 
-#include "MixerChannelLcdSpinBox.h"
 #include "TrackView.h"
 
 #include "InstrumentTrack.h"
@@ -38,6 +37,7 @@ namespace lmms::gui
 class InstrumentTrackWindow;
 class Knob;
 class MidiCCRackView;
+class MixerChannelLcdSpinBox;
 class TrackContainerView;
 class TrackLabelButton;
 

include/InstrumentTrackWindow.h

@@ -27,24 +27,21 @@
 
 #include <QWidget>
 
-#include "AutomatableButton.h"
+#include "InstrumentTrack.h"
 #include "ModelView.h"
 #include "SerializingObject.h"
-#include "PluginView.h"
 
 class QLabel;
 class QLineEdit;
-class QWidget;
 class QMdiSubWindow;
 
 namespace lmms
 {
 
-class InstrumentTrack;
-
 namespace gui
 {
 
+class AutomatableButton;
 class EffectRackView;
 class MixerChannelLcdSpinBox;
 class InstrumentFunctionArpeggioView;
@@ -52,7 +49,6 @@ class InstrumentFunctionNoteStackingView;
 class InstrumentMidiIOView;
 class InstrumentTuningView;
 class InstrumentSoundShapingView;
-class InstrumentTrackShapingView;
 class InstrumentTrackView;
 class Knob;
 class LcdSpinBox;

include/Knob.h

@@ -26,19 +26,15 @@
 #define LMMS_GUI_KNOB_H
 
 #include <memory>
-#include <QTextDocument>
 
 #include "FloatModelEditorBase.h"
 
 
-class QPixmap;
 
 namespace lmms::gui
 {
 
 
-class SimpleTextFloat;
-
 enum class KnobType
 {
 	Dark28, Bright26, Small17, Vintage32, Styled

include/LedCheckBox.h

@@ -28,7 +28,6 @@
 #include "AutomatableButton.h"
 
 
-class QPixmap;
 
 
 namespace lmms::gui

include/LfoController.h

@@ -25,9 +25,7 @@
 #ifndef LMMS_LFO_CONTROLLER_H
 #define LMMS_LFO_CONTROLLER_H
 
-#include <QWidget>
 
-#include "Model.h"
 #include "AutomatableModel.h"
 #include "Controller.h"
 #include "ControllerDialog.h"
@@ -40,8 +38,7 @@ namespace lmms
 namespace gui
 {
 
-class automatableButtonGroup;
-class LedCheckBox;
+class AutomatableButtonGroup;
 class PixmapButton;
 class Knob;
 class TempoSyncKnob;
@@ -120,8 +117,8 @@ protected:
 	Knob * m_amountKnob;
 	Knob * m_phaseKnob;
 	PixmapButton * m_userLfoBtn;
-	automatableButtonGroup * m_waveBtnGrp;
-	automatableButtonGroup * m_multiplierBtnGrp;
+	AutomatableButtonGroup * m_waveBtnGrp;
+	AutomatableButtonGroup * m_multiplierBtnGrp;
 
 
 private:

include/LinkedModelGroupViews.h

@@ -40,7 +40,7 @@ class LinkedModelGroups;
 namespace gui
 {
 
-class Control;
+class Control;  // IWYU pragma: keep
 
 /**
 	@file LinkedModelGroupViews.h

include/LmmsSemaphore.h

@@ -40,7 +40,6 @@
 #    include <semaphore.h>
 #endif
 
-#include <system_error>
 
 namespace lmms {
 

include/Lv2ControlBase.h

@@ -32,7 +32,6 @@
 #include <lilv/lilv.h>
 #include <memory>
 
-#include "DataFile.h"
 #include "LinkedModelGroups.h"
 #include "lmms_export.h"
 #include "Plugin.h"

include/Lv2Features.h

@@ -32,8 +32,8 @@
 #include <map>
 #include <string_view>
 #include <vector>
-#include "Lv2Manager.h"
 
+#include <lv2/core/lv2.h>
 
 namespace lmms
 {

include/Lv2Proc.h

@@ -57,10 +57,6 @@ namespace Lv2Ports
 	struct Audio;
 	struct PortBase;
 	struct AtomSeq;
-
-	enum class Type;
-	enum class Flow;
-	enum class Vis;
 }
 
 

include/Lv2ViewBase.h

@@ -37,7 +37,6 @@
 
 class QPushButton;
 class QMdiSubWindow;
-class QLabel;
 namespace lmms
 {
 
@@ -49,7 +48,6 @@ class Lv2ControlBase;
 namespace gui
 {
 
-class LedCheckBox;
 
 //! View for one processor, Lv2ViewBase contains 2 of those for mono plugins
 class Lv2ViewProc : public LinkedModelGroupView

include/Lv2Worker.h

@@ -29,7 +29,6 @@
 
 #ifdef LMMS_HAVE_LV2
 
-#include <lilv/lilv.h>
 #include <lv2/worker/worker.h>
 #include <thread>
 #include <vector>

include/MainWindow.h

@@ -36,21 +36,16 @@
 class QAction;
 class QDomElement;
 class QGridLayout;
-class QMdiArea;
 
 namespace lmms
 {
 
-class ConfigManager;
-
 namespace gui
 {
 
-class FileBrowser;
 class PluginView;
 class SubWindow;
 class ToolButton;
-class GuiApplication;
 
 
 class MainWindow : public QMainWindow

include/MidiAlsaRaw.h

@@ -31,7 +31,6 @@
 
 #include <alsa/asoundlib.h>
 
-#include <QMap>
 #include <QThread>
 
 #include "MidiClient.h"

include/MidiAlsaSeq.h

@@ -39,7 +39,6 @@
 #include "MidiClient.h"
 
 
-struct pollfd;
 
 
 namespace lmms

include/MidiJack.h

@@ -39,7 +39,6 @@
 
 #include "MidiClient.h"
 
-class QLineEdit;
 
 namespace lmms
 {

include/MixerChannelView.h

@@ -25,26 +25,26 @@
 #ifndef LMMS_GUI_MIXER_CHANNEL_VIEW_H
 #define LMMS_GUI_MIXER_CHANNEL_VIEW_H
 
-#include <QGraphicsView>
-#include <QLabel>
-#include <QLineEdit>
-#include <QPixmap>
-#include <QStackedWidget>
 #include <QWidget>
 
-#include "EffectRackView.h"
-#include "Fader.h"
-#include "Knob.h"
-#include "LcdWidget.h"
-#include "PixmapButton.h"
-#include "SendButtonIndicator.h"
+class QGraphicsView;
+class QLabel;
+class QLineEdit;
+class QStackedWidget;
 
 namespace lmms {
 class MixerChannel;
 }
 
 namespace lmms::gui {
+class AutomatableButton;
+class EffectRackView;
+class Fader;
+class Knob;
+class LcdWidget;
+class MixerView;
 class PeakIndicator;
+class SendButtonIndicator;
 
 
 class MixerChannelView : public QWidget

include/MixerView.h

@@ -26,17 +26,16 @@
 #define LMMS_GUI_MIXER_VIEW_H
 
 #include <QWidget>
-#include <QHBoxLayout>
-#include <QStackedLayout>
-#include <QScrollArea>
 
 #include "MixerChannelView.h"
 #include "ModelView.h"
-#include "Engine.h"
-#include "Fader.h"
-#include "PixmapButton.h"
-#include "embed.h"
-#include "EffectRackView.h"
+#include "SerializingObject.h"
+
+class QDomDocument;  // IWYU pragma: keep
+class QDomElement;  // IWYU pragma: keep
+class QHBoxLayout;
+class QStackedLayout;
+class QScrollArea;
 
 namespace lmms
 {

include/PatternTrack.h

@@ -37,7 +37,6 @@ class TrackContainer;
 namespace gui
 {
 
-class TrackLabelButton;
 class PatternTrackView;
 
 } // namespace gui

include/PianoRoll.h

@@ -40,11 +40,8 @@
 #include "StepRecorder.h"
 #include "StepRecorderWidget.h"
 
-class QPainter;
-class QPixmap;
 class QPushButton;
 class QScrollBar;
-class QString;
 class QMenu;
 class QToolButton;
 
@@ -52,7 +49,6 @@ namespace lmms
 {
 
 
-class NotePlayHandle;
 class MidiClip;
 
 

include/PluginBrowser.h

@@ -30,7 +30,6 @@
 #include "SideBarWidget.h"
 #include "Plugin.h"
 
-class QLineEdit;
 class QTreeWidget;
 
 namespace lmms::gui

include/PluginFactory.h

@@ -30,14 +30,13 @@
 #include <vector>
 
 #include <QFileInfo>
-#include <QHash>
 #include <QList>
 #include <QString>
 
 #include "lmms_export.h"
 #include "Plugin.h"
 
-class QLibrary;
+class QLibrary;  // IWYU pragma: keep
 
 namespace lmms
 {

include/RemotePlugin.h

@@ -25,17 +25,20 @@
 #ifndef LMMS_REMOTE_PLUGIN_H
 #define LMMS_REMOTE_PLUGIN_H
 
+#include <QThread>
+#include <QProcess>
+#if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
+#include <QRecursiveMutex>  // IWYU pragma: keep
+#endif
+
 #include "RemotePluginBase.h"
 #include "SharedMemory.h"
-
-#if (QT_VERSION >= QT_VERSION_CHECK(5,14,0))
-	#include <QRecursiveMutex>
-#endif
+#include "LmmsTypes.h"
 
 namespace lmms
 {
 
-
+class MidiEvent;
 class RemotePlugin;
 class SampleFrame;
 

include/RemotePluginBase.h

@@ -25,17 +25,14 @@
 #ifndef LMMS_REMOTE_PLUGIN_BASE_H
 #define LMMS_REMOTE_PLUGIN_BASE_H
 
-#include "MidiEvent.h"
-
-#include "lmmsconfig.h"
-
-#include <atomic>
+#include <atomic>  // IWYU pragma: keep
 #include <vector>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <string>
-#include <cassert>
+
+#include "lmmsconfig.h"
 
 #if !(defined(LMMS_HAVE_SYS_IPC_H) && defined(LMMS_HAVE_SEMAPHORE_H))
 #define SYNC_WITH_SHM_FIFO
@@ -50,7 +47,7 @@
 #endif // !(LMMS_HAVE_SYS_IPC_H && LMMS_HAVE_SEMAPHORE_H)
 
 #ifdef LMMS_HAVE_LOCALE_H
-#include <clocale>
+#include <clocale>  // IWYU pragma: keep
 #endif
 
 #ifdef LMMS_HAVE_PTHREAD_H
@@ -69,14 +66,11 @@
 
 #else // BUILD_REMOTE_PLUGIN_CLIENT
 #include "lmms_export.h"
-#include <QMutex>
-#include <QProcess>
-#include <QThread>
 #include <QString>
 
 #ifndef SYNC_WITH_SHM_FIFO
 #include <poll.h>
-#include <unistd.h>
+#include <unistd.h>  // IWYU pragma: keep
 #endif // SYNC_WITH_SHM_FIFO
 
 #endif // BUILD_REMOTE_PLUGIN_CLIENT

include/RemotePluginClient.h

@@ -38,6 +38,8 @@
 #	include <unistd.h>
 #endif
 
+#include "LmmsTypes.h"
+#include "MidiEvent.h"
 #include "SharedMemory.h"
 #include "VstSyncData.h"
 

include/Sample.h

@@ -25,7 +25,6 @@
 #ifndef LMMS_SAMPLE_H
 #define LMMS_SAMPLE_H
 
-#include <cmath>
 #include <memory>
 
 #include "AudioResampler.h"

include/SampleBuffer.h

@@ -25,11 +25,8 @@
 #ifndef LMMS_SAMPLE_BUFFER_H
 #define LMMS_SAMPLE_BUFFER_H
 
-#include <QByteArray>
 #include <QString>
 #include <memory>
-#include <optional>
-#include <samplerate.h>
 #include <vector>
 
 #include "AudioEngine.h"

include/SampleDecoder.h

@@ -26,7 +26,6 @@
 #define LMMS_SAMPLE_DECODER_H
 
 #include <QString>
-#include <functional>
 #include <optional>
 #include <string>
 #include <vector>

include/SamplePlayHandle.h

@@ -27,7 +27,6 @@
 #define LMMS_SAMPLE_PLAY_HANDLE_H
 
 #include "Sample.h"
-#include "SampleBuffer.h"
 #include "AutomatableModel.h"
 #include "PlayHandle.h"
 
@@ -38,7 +37,6 @@ namespace lmms
 class PatternTrack;
 class SampleClip;
 class Track;
-class AudioBusHandle;
 
 
 class LMMS_EXPORT SamplePlayHandle : public PlayHandle

include/SampleThumbnail.h

@@ -27,15 +27,19 @@
 #define LMMS_SAMPLE_THUMBNAIL_H
 
 #include <QDateTime>
-#include <QPainter>
 #include <QRect>
 #include <memory>
 
-#include "Sample.h"
 #include "lmms_export.h"
+#include "SampleBuffer.h"
+#include "SampleFrame.h"
+
+class QPainter;
 
 namespace lmms {
 
+class Sample;
+
 /**
    Allows for visualizing sample data.
 

include/SampleTrackView.h

@@ -26,19 +26,17 @@
 #define LMMS_GUI_SAMPLE_TRACK_VIEW_H
 
 
-#include "MixerChannelLcdSpinBox.h"
+#include "SampleTrack.h"
 #include "TrackView.h"
 
 namespace lmms
 {
 
-class SampleTrack;
-
-
 namespace gui
 {
 
 class Knob;
+class MixerChannelLcdSpinBox;
 class SampleTrackWindow;
 class TrackLabelButton;
 

include/SampleTrackWindow.h

@@ -30,13 +30,13 @@
 #include "ModelView.h"
 #include "SampleTrack.h"
 #include "SerializingObject.h"
-#include "AutomatableButton.h"
 
 class QLineEdit;
 
 namespace lmms::gui
 {
 
+class AutomatableButton;
 class EffectRackView;
 class Knob;
 class MixerChannelLcdSpinBox;

include/Song.h

@@ -28,8 +28,8 @@
 #include <array>
 #include <memory>
 
-#include <QHash>
 #include <QString>
+#include <QHash>  // IWYU pragma: keep
 
 #include "AudioEngine.h"
 #include "Controller.h"
@@ -50,11 +50,8 @@ class Scale;
 
 namespace gui
 {
-
-class TimeLineWidget;
 class SongEditor;
 class ControllerRackView;
-
 }
 
 

include/SongEditor.h

@@ -26,7 +26,6 @@
 #ifndef LMMS_GUI_SONG_EDITOR_H
 #define LMMS_GUI_SONG_EDITOR_H
 
-#include "AutomatableModel.h"
 #include "Editor.h"
 #include "TrackContainerView.h"
 
@@ -36,6 +35,7 @@ class QScrollBar;
 namespace lmms
 {
 
+class IntModel;
 class Song;
 class ComboBoxModel;
 

include/StepRecorder.h

@@ -21,7 +21,6 @@
 #ifndef LMMS_STEP_RECORDER_H
 #define LMMS_STEP_RECORDER_H
 
-#include <QColor>
 #include <QElapsedTimer>
 #include <QTimer>
 #include <QObject>

include/SubWindow.h

@@ -34,9 +34,7 @@
 
 class QGraphicsDropShadowEffect;
 class QLabel;
-class QMoveEvent;
 class QPushButton;
-class QResizeEvent;
 class QWidget;
 
 namespace lmms::gui

include/TimeLineWidget.h

@@ -27,7 +27,6 @@
 
 #include <array>
 
-#include <QBrush>
 #include <QSize>
 #include <QWidget>
 
@@ -35,7 +34,6 @@
 #include "embed.h"
 
 
-class QPixmap;
 class QToolBar;
 
 namespace lmms {
@@ -47,9 +45,7 @@ class Timeline;
 namespace lmms::gui
 {
 
-class NStateButton;
 class TextFloat;
-class SongEditor;
 
 
 class TimeLineWidget : public QWidget

include/TrackContentWidget.h

@@ -30,8 +30,8 @@
 #include "JournallingObject.h"
 #include "TimePos.h"
 
+class QMimeData;  // IWYU pragma: keep
 
-class QMimeData;
 
 namespace lmms
 {
@@ -41,8 +41,8 @@ class Track;
 namespace gui
 {
 
+class ClipView;  // IWYU pragma: keep
 class TrackView;
-class ClipView;
 
 class TrackContentWidget : public QWidget, public JournallingObject
 {

include/TrackOperationsWidget.h

@@ -26,14 +26,13 @@
 #define LMMS_GUI_TRACK_OPERATIONS_WIDGET_H
 
 #include <QWidget>
-#include "AutomatableButton.h"
 
 class QPushButton;
 
 namespace lmms::gui
 {
 
-class PixmapButton;
+class AutomatableButton;
 class TrackGrip;
 class TrackView;
 

include/VstSyncController.h

@@ -29,12 +29,11 @@
 #include <QObject>
 
 #include "SharedMemory.h"
-#include "VstSyncData.h"
+#include "VstSyncData.h"  // IWYU pragma: keep
 
 namespace lmms
 {
 
-
 class VstSyncController : public QObject
 {
 	Q_OBJECT

include/embed.h

@@ -32,8 +32,9 @@
 #include <QString>
 
 #include "lmms_export.h"
+#ifdef PLUGIN_NAME
 #include "LmmsCommonMacros.h"
-
+#endif
 
 namespace lmms {