diff --git a/examples/charts/audio/widget.h b/examples/charts/audio/widget.h
index c442e51..edb6c8a 100644
--- a/examples/charts/audio/widget.h
+++ b/examples/charts/audio/widget.h
@@ -30,7 +30,10 @@ QT_CHARTS_END_NAMESPACE
 QT_CHARTS_USE_NAMESPACE
 
 class XYSeriesIODevice;
+
+QT_BEGIN_NAMESPACE
 class QAudioInput;
+QT_END_NAMESPACE
 
 class Widget : public QWidget
 {
diff --git a/examples/charts/callout/callout.h b/examples/charts/callout/callout.h
index b4a0e35..10988c7 100644
--- a/examples/charts/callout/callout.h
+++ b/examples/charts/callout/callout.h
@@ -22,7 +22,9 @@
 #include <QtWidgets/QGraphicsItem>
 #include <QtGui/QFont>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsSceneMouseEvent;
+QT_END_NAMESPACE
 
 class Callout : public QGraphicsItem
 {
diff --git a/examples/charts/callout/view.h b/examples/charts/callout/view.h
index 22fd2b2..c1a6e0d 100644
--- a/examples/charts/callout/view.h
+++ b/examples/charts/callout/view.h
@@ -21,14 +21,17 @@
 #include <QtWidgets/QGraphicsView>
 #include <QtCharts/QChartGlobal>
 
+QT_BEGIN_NAMESPACE
+class QGraphicsScene;
+class QMouseEvent;
+class QResizeEvent;
+QT_END_NAMESPACE
+
 QT_CHARTS_BEGIN_NAMESPACE
 class QChart;
 QT_CHARTS_END_NAMESPACE
 
-class QGraphicsScene;
-class QResizeEvent;
 class Callout;
-class QMouseEvent;
 
 QT_CHARTS_USE_NAMESPACE
 
diff --git a/examples/charts/chartthemes/themewidget.h b/examples/charts/chartthemes/themewidget.h
index 3471773..a863a67 100644
--- a/examples/charts/chartthemes/themewidget.h
+++ b/examples/charts/chartthemes/themewidget.h
@@ -22,8 +22,10 @@
 #include <QtWidgets/QWidget>
 #include <QtCharts/QChartGlobal>
 
+QT_BEGIN_NAMESPACE
 class QComboBox;
 class QCheckBox;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 class QChartView;
diff --git a/examples/charts/nesteddonuts/widget.h b/examples/charts/nesteddonuts/widget.h
index 997a365..1f2e056 100644
--- a/examples/charts/nesteddonuts/widget.h
+++ b/examples/charts/nesteddonuts/widget.h
@@ -21,7 +21,9 @@
 #include <QtWidgets/QWidget>
 #include <QtCharts/QPieSeries>
 
+QT_BEGIN_NAMESPACE
 class QTimer;
+QT_END_NAMESPACE
 
 QT_CHARTS_USE_NAMESPACE
 
diff --git a/examples/charts/piechartcustomization/brushtool.h b/examples/charts/piechartcustomization/brushtool.h
index 71403f5..07a66ba 100644
--- a/examples/charts/piechartcustomization/brushtool.h
+++ b/examples/charts/piechartcustomization/brushtool.h
@@ -21,8 +21,10 @@
 #include <QtWidgets/QWidget>
 #include <QtGui/QBrush>
 
+QT_BEGIN_NAMESPACE
 class QPushButton;
 class QComboBox;
+QT_END_NAMESPACE
 
 class BrushTool : public QWidget
 {
diff --git a/examples/charts/piechartcustomization/mainwidget.h b/examples/charts/piechartcustomization/mainwidget.h
index 5ca1b09..3d68bb7 100644
--- a/examples/charts/piechartcustomization/mainwidget.h
+++ b/examples/charts/piechartcustomization/mainwidget.h
@@ -21,11 +21,14 @@
 #include <QtWidgets/QWidget>
 #include <QtCharts/QChartGlobal>
 
+QT_BEGIN_NAMESPACE
 class QLineEdit;
 class QPushButton;
 class QCheckBox;
 class QComboBox;
 class QDoubleSpinBox;
+QT_END_NAMESPACE
+
 class PenTool;
 class BrushTool;
 class CustomSlice;
diff --git a/examples/charts/piechartcustomization/pentool.h b/examples/charts/piechartcustomization/pentool.h
index 009c58d..62776bc 100644
--- a/examples/charts/piechartcustomization/pentool.h
+++ b/examples/charts/piechartcustomization/pentool.h
@@ -21,9 +21,11 @@
 #include <QtWidgets/QWidget>
 #include <QtGui/QPen>
 
+QT_BEGIN_NAMESPACE
 class QPushButton;
 class QDoubleSpinBox;
 class QComboBox;
+QT_END_NAMESPACE
 
 class PenTool : public QWidget
 {
diff --git a/examples/charts/qmloscilloscope/datasource.h b/examples/charts/qmloscilloscope/datasource.h
index 6029700..16c1724 100644
--- a/examples/charts/qmloscilloscope/datasource.h
+++ b/examples/charts/qmloscilloscope/datasource.h
@@ -22,7 +22,9 @@
 #include <QtCore/QObject>
 #include <QtCharts/QAbstractSeries>
 
+QT_BEGIN_NAMESPACE
 class QQuickView;
+QT_END_NAMESPACE
 
 QT_CHARTS_USE_NAMESPACE
 
diff --git a/examples/charts/zoomlinechart/chart.h b/examples/charts/zoomlinechart/chart.h
index b86a31e..b294146 100644
--- a/examples/charts/zoomlinechart/chart.h
+++ b/examples/charts/zoomlinechart/chart.h
@@ -21,7 +21,9 @@
 
 #include <QtCharts/QChart>
 
+QT_BEGIN_NAMESPACE
 class QGestureEvent;
+QT_END_NAMESPACE
 
 QT_CHARTS_USE_NAMESPACE
 
diff --git a/src/charts/axis/datetimeaxis/qdatetimeaxis.h b/src/charts/axis/datetimeaxis/qdatetimeaxis.h
index 5172b53..5da78e7 100644
--- a/src/charts/axis/datetimeaxis/qdatetimeaxis.h
+++ b/src/charts/axis/datetimeaxis/qdatetimeaxis.h
@@ -21,7 +21,9 @@
 
 #include <QtCharts/QAbstractAxis>
 
+QT_BEGIN_NAMESPACE
 class QDateTime;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/axis/logvalueaxis/qlogvalueaxis.h b/src/charts/axis/logvalueaxis/qlogvalueaxis.h
index 6b73986..d1f26fd 100644
--- a/src/charts/axis/logvalueaxis/qlogvalueaxis.h
+++ b/src/charts/axis/logvalueaxis/qlogvalueaxis.h
@@ -21,7 +21,9 @@
 
 #include <QtCharts/QAbstractAxis>
 
+QT_BEGIN_NAMESPACE
 class QDateTime;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/axis/qabstractaxis_p.h b/src/charts/axis/qabstractaxis_p.h
index 9a3f95e..edb699e 100644
--- a/src/charts/axis/qabstractaxis_p.h
+++ b/src/charts/axis/qabstractaxis_p.h
@@ -33,7 +33,9 @@
 #include <QtCharts/QChart>
 #include <QtCore/QDebug>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsItem;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/barchart/qbarmodelmapper.h b/src/charts/barchart/qbarmodelmapper.h
index 7bd1bae..d14d39e 100644
--- a/src/charts/barchart/qbarmodelmapper.h
+++ b/src/charts/barchart/qbarmodelmapper.h
@@ -22,7 +22,9 @@
 #include <QtCharts/QChartGlobal>
 #include <QtCore/QObject>
 
+QT_BEGIN_NAMESPACE
 class QAbstractItemModel;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/barchart/qbarmodelmapper_p.h b/src/charts/barchart/qbarmodelmapper_p.h
index 6e4f486..930d8fe 100644
--- a/src/charts/barchart/qbarmodelmapper_p.h
+++ b/src/charts/barchart/qbarmodelmapper_p.h
@@ -31,7 +31,9 @@
 #include <QtCore/QObject>
 #include <QtCharts/QBarModelMapper>
 
+QT_BEGIN_NAMESPACE
 class QModelIndex;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/boxplotchart/qboxplotmodelmapper.h b/src/charts/boxplotchart/qboxplotmodelmapper.h
index 91ee6f6..0a179bf 100644
--- a/src/charts/boxplotchart/qboxplotmodelmapper.h
+++ b/src/charts/boxplotchart/qboxplotmodelmapper.h
@@ -22,7 +22,9 @@
 #include <QtCharts/QChartGlobal>
 #include <QtCore/QObject>
 
+QT_BEGIN_NAMESPACE
 class QAbstractItemModel;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/boxplotchart/qboxplotmodelmapper_p.h b/src/charts/boxplotchart/qboxplotmodelmapper_p.h
index efdf754..758f8ec 100644
--- a/src/charts/boxplotchart/qboxplotmodelmapper_p.h
+++ b/src/charts/boxplotchart/qboxplotmodelmapper_p.h
@@ -31,7 +31,9 @@
 #include <QtCore/QObject>
 #include <QtCharts/QBoxPlotModelMapper>
 
+QT_BEGIN_NAMESPACE
 class QModelIndex;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/chartbackground_p.h b/src/charts/chartbackground_p.h
index 8fec472..8a5694f 100644
--- a/src/charts/chartbackground_p.h
+++ b/src/charts/chartbackground_p.h
@@ -31,7 +31,10 @@
 #include <QtCharts/QChartGlobal>
 #include <QtWidgets/QGraphicsRectItem>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsDropShadowEffect;
+QT_END_NAMESPACE
+
 QT_CHARTS_BEGIN_NAMESPACE
 
 class ChartBackground: public QGraphicsRectItem
diff --git a/src/charts/piechart/piechartitem_p.h b/src/charts/piechart/piechartitem_p.h
index 3f952cc..4d6d84d 100644
--- a/src/charts/piechart/piechartitem_p.h
+++ b/src/charts/piechart/piechartitem_p.h
@@ -33,7 +33,10 @@
 #include <private/piesliceitem_p.h>
 #include <QtCore/QPointer>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsItem;
+QT_END_NAMESPACE
+
 QT_CHARTS_BEGIN_NAMESPACE
 class QPieSlice;
 class ChartPresenter;
diff --git a/src/charts/piechart/qpiemodelmapper.h b/src/charts/piechart/qpiemodelmapper.h
index dde48c9..9daf1e0 100644
--- a/src/charts/piechart/qpiemodelmapper.h
+++ b/src/charts/piechart/qpiemodelmapper.h
@@ -22,7 +22,9 @@
 #include <QtCharts/QChartGlobal>
 #include <QtCore/QObject>
 
+QT_BEGIN_NAMESPACE
 class QAbstractItemModel;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/piechart/qpiemodelmapper_p.h b/src/charts/piechart/qpiemodelmapper_p.h
index 0691042..9c94c38 100644
--- a/src/charts/piechart/qpiemodelmapper_p.h
+++ b/src/charts/piechart/qpiemodelmapper_p.h
@@ -31,7 +31,9 @@
 #include <QtCore/QObject>
 #include <QtCharts/QPieModelMapper>
 
+QT_BEGIN_NAMESPACE
 class QModelIndex;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/qabstractseries_p.h b/src/charts/qabstractseries_p.h
index 1e72c23..160297c 100644
--- a/src/charts/qabstractseries_p.h
+++ b/src/charts/qabstractseries_p.h
@@ -32,7 +32,9 @@
 #include <QtCharts/QChart>
 #include <private/abstractdomain_p.h>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsItem;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/qchart.h b/src/charts/qchart.h
index 1836f65..6634581 100644
--- a/src/charts/qchart.h
+++ b/src/charts/qchart.h
@@ -24,7 +24,9 @@
 #include <QtWidgets/QGraphicsWidget>
 #include <QtCore/QMargins>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsSceneResizeEvent;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/qchartview.h b/src/charts/qchartview.h
index 37c45d9..6de8b6c 100644
--- a/src/charts/qchartview.h
+++ b/src/charts/qchartview.h
@@ -24,8 +24,10 @@
 #include <QtCharts/QChart>
 #include <QtWidgets/QGraphicsView>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsScene;
 class QRubberBand;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/qchartview_p.h b/src/charts/qchartview_p.h
index 659b4fe..59de3dd 100644
--- a/src/charts/qchartview_p.h
+++ b/src/charts/qchartview_p.h
@@ -30,12 +30,14 @@
 
 #include <QtCharts/QChartView>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsScene;
-class ChartPresenter;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
 class QChart;
+class ChartPresenter;
 class QChartView;
 
 class QChartViewPrivate
diff --git a/src/charts/scroller_p.h b/src/charts/scroller_p.h
index 77b3352..d94d711 100644
--- a/src/charts/scroller_p.h
+++ b/src/charts/scroller_p.h
@@ -34,7 +34,9 @@
 #include <QtCore/QTime>
 #include <QtCore/QPointF>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsSceneMouseEvent;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/xychart/qxymodelmapper.h b/src/charts/xychart/qxymodelmapper.h
index d0e0d9d..e357ebf 100644
--- a/src/charts/xychart/qxymodelmapper.h
+++ b/src/charts/xychart/qxymodelmapper.h
@@ -22,7 +22,9 @@
 #include <QtCharts/QChartGlobal>
 #include <QtCore/QObject>
 
+QT_BEGIN_NAMESPACE
 class QAbstractItemModel;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/xychart/qxymodelmapper_p.h b/src/charts/xychart/qxymodelmapper_p.h
index c38df0c..0c16396 100644
--- a/src/charts/xychart/qxymodelmapper_p.h
+++ b/src/charts/xychart/qxymodelmapper_p.h
@@ -31,9 +31,11 @@
 #include <QtCharts/QXYModelMapper>
 #include <QtCore/QObject>
 
+QT_BEGIN_NAMESPACE
 class QModelIndex;
 class QAbstractItemModel;
 class QPointF;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/src/charts/xychart/qxyseries.h b/src/charts/xychart/qxyseries.h
index 4e3d876..53a7a93 100644
--- a/src/charts/xychart/qxyseries.h
+++ b/src/charts/xychart/qxyseries.h
@@ -24,7 +24,9 @@
 #include <QtGui/QPen>
 #include <QtGui/QBrush>
 
+QT_BEGIN_NAMESPACE
 class QModelIndex;
+QT_END_NAMESPACE
 
 QT_CHARTS_BEGIN_NAMESPACE
 
diff --git a/tests/auto/inc/tst_definitions.h b/tests/auto/inc/tst_definitions.h
index fe14ea1..e2e73af 100644
--- a/tests/auto/inc/tst_definitions.h
+++ b/tests/auto/inc/tst_definitions.h
@@ -23,6 +23,7 @@
 #include <QtTest/QtTest>
 #include <QtWidgets/QPushButton>
 
+QT_BEGIN_NAMESPACE
 namespace QTest
 {
     // This was deprecated in Qt5. This is a small hack for the sake of compatibility.
@@ -31,6 +32,7 @@ namespace QTest
         return QTest::qWaitForWindowExposed(window);
     }
 }
+QT_END_NAMESPACE
 
 #define TRY_COMPARE(actual, expected) { \
     do { \
diff --git a/tests/manual/boxplottester/mainwidget.h b/tests/manual/boxplottester/mainwidget.h
index 5e65642..b4b4c42 100644
--- a/tests/manual/boxplottester/mainwidget.h
+++ b/tests/manual/boxplottester/mainwidget.h
@@ -29,7 +29,10 @@
 #include <QtWidgets/QCheckBox>
 #include <QtWidgets/QDoubleSpinBox>
 
+QT_BEGIN_NAMESPACE
 class QGridLayout;
+QT_END_NAMESPACE
+
 class CustomTableModel;
 class PenTool;
 
diff --git a/tests/manual/boxplottester/pentool.h b/tests/manual/boxplottester/pentool.h
index 009c58d..62776bc 100644
--- a/tests/manual/boxplottester/pentool.h
+++ b/tests/manual/boxplottester/pentool.h
@@ -21,9 +21,11 @@
 #include <QtWidgets/QWidget>
 #include <QtGui/QPen>
 
+QT_BEGIN_NAMESPACE
 class QPushButton;
 class QDoubleSpinBox;
 class QComboBox;
+QT_END_NAMESPACE
 
 class PenTool : public QWidget
 {
diff --git a/tests/manual/chartviewer/grid.h b/tests/manual/chartviewer/grid.h
index 74eec0e..42a6b8e 100644
--- a/tests/manual/chartviewer/grid.h
+++ b/tests/manual/chartviewer/grid.h
@@ -23,7 +23,10 @@
 #include <QtWidgets/QGraphicsWidget>
 #include <QtCharts/QChartGlobal>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsGridLayout;
+QT_END_NAMESPACE
+
 class Chart;
 
 QT_CHARTS_BEGIN_NAMESPACE
diff --git a/tests/manual/chartviewer/view.h b/tests/manual/chartviewer/view.h
index a5bac1b..b5cdcdc 100644
--- a/tests/manual/chartviewer/view.h
+++ b/tests/manual/chartviewer/view.h
@@ -20,8 +20,10 @@
 #define VIEW_H
 #include <QtWidgets/QGraphicsView>
 
+QT_BEGIN_NAMESPACE
 class QGraphicsScene;
 class QResizeEvent;
+QT_END_NAMESPACE
 
 class View: public QGraphicsView
 {
diff --git a/tests/manual/chartviewer/window.h b/tests/manual/chartviewer/window.h
index 7419735..1c9f6ac 100644
--- a/tests/manual/chartviewer/window.h
+++ b/tests/manual/chartviewer/window.h
@@ -23,15 +23,17 @@
 #include <QtCore/QHash>
 #include <QtWidgets/QComboBox>
 
+QT_BEGIN_NAMESPACE
 class QCheckBox;
+class QGraphicsLinearLayout;
 class QGraphicsRectItem;
 class QGraphicsScene;
 class QGraphicsWidget;
+QT_END_NAMESPACE
+
 class View;
-class QGraphicsLinearLayout;
 class Chart;
 class Grid;
-class QPushButton;
 
 QT_CHARTS_BEGIN_NAMESPACE
 class QChart;
diff --git a/tests/manual/chartwidgettest/dataseriedialog.h b/tests/manual/chartwidgettest/dataseriedialog.h
index f90b9ae..f5f1d74 100644
--- a/tests/manual/chartwidgettest/dataseriedialog.h
+++ b/tests/manual/chartwidgettest/dataseriedialog.h
@@ -21,8 +21,10 @@
 
 #include <QtWidgets/QDialog>
 
+QT_BEGIN_NAMESPACE
 class QGroupBox;
 class QCheckBox;
+QT_END_NAMESPACE
 
 class DataSerieDialog : public QDialog
 {
diff --git a/tests/manual/chartwidgettest/mainwidget.h b/tests/manual/chartwidgettest/mainwidget.h
index c27f811..b11bd53 100644
--- a/tests/manual/chartwidgettest/mainwidget.h
+++ b/tests/manual/chartwidgettest/mainwidget.h
@@ -24,9 +24,11 @@
 #include <QtCharts/QChartView>
 #include <QtWidgets/QWidget>
 
+QT_BEGIN_NAMESPACE
 class QSpinBox;
 class QCheckBox;
 class QGridLayout;
+QT_END_NAMESPACE
 
 QT_CHARTS_USE_NAMESPACE
 
diff --git a/tests/manual/polarcharttest/mainwindow.h b/tests/manual/polarcharttest/mainwindow.h
index 237e262..1e6f21c 100644
--- a/tests/manual/polarcharttest/mainwindow.h
+++ b/tests/manual/polarcharttest/mainwindow.h
@@ -28,14 +28,17 @@
 #include <QtCharts/QSplineSeries>
 #include <QtCharts/QAreaSeries>
 
+QT_BEGIN_NAMESPACE
+class QBrush;
+class QPen;
+
 namespace Ui {
 class MainWindow;
 }
+QT_END_NAMESPACE
 
-QT_CHARTS_USE_NAMESPACE
 
-class QBrush;
-class QPen;
+QT_CHARTS_USE_NAMESPACE
 
 class MainWindow : public QMainWindow
 {