diff --git a/src/widgets/kernel/qboxlayout.cpp b/src/widgets/kernel/qboxlayout.cpp
index 157fa55d2e..a186326551 100644
--- a/src/widgets/kernel/qboxlayout.cpp
+++ b/src/widgets/kernel/qboxlayout.cpp
@@ -51,20 +51,6 @@
 
 QT_BEGIN_NAMESPACE
 
-/*
-    Returns \c true if the \a widget can be added to the \a layout;
-    otherwise returns \c false.
-*/
-static bool checkWidget(QLayout *layout, QWidget *widget)
-{
-    if (!widget) {
-        qWarning("QLayout: Cannot add null widget to %s/%s", layout->metaObject()->className(),
-                  layout->objectName().toLocal8Bit().data());
-        return false;
-    }
-    return true;
-}
-
 struct QBoxLayoutItem
 {
     QBoxLayoutItem(QLayoutItem *it, int stretch_ = 0)
@@ -958,6 +944,8 @@ void QBoxLayout::insertSpacerItem(int index, QSpacerItem *spacerItem)
 void QBoxLayout::insertLayout(int index, QLayout *layout, int stretch)
 {
     Q_D(QBoxLayout);
+    if (!d->checkLayout(layout))
+        return;
     if (!adoptLayout(layout))
         return;
     if (index < 0)                                // append
@@ -991,7 +979,7 @@ void QBoxLayout::insertWidget(int index, QWidget *widget, int stretch,
                               Qt::Alignment alignment)
 {
     Q_D(QBoxLayout);
-    if (!checkWidget(this, widget))
+    if (!d->checkWidget(widget))
          return;
     addChildWidget(widget);
     if (index < 0)                                // append
diff --git a/src/widgets/kernel/qformlayout.cpp b/src/widgets/kernel/qformlayout.cpp
index 239e1ce1e2..9f545b858a 100644
--- a/src/widgets/kernel/qformlayout.cpp
+++ b/src/widgets/kernel/qformlayout.cpp
@@ -1280,6 +1280,8 @@ void QFormLayout::addRow(QLayout *layout)
 void QFormLayout::insertRow(int row, QWidget *label, QWidget *field)
 {
     Q_D(QFormLayout);
+    if ((label && !d->checkWidget(label)) || (field && !d->checkWidget(field)))
+        return;
 
     row = d->insertRow(row);
     if (label)
@@ -1295,6 +1297,8 @@ void QFormLayout::insertRow(int row, QWidget *label, QWidget *field)
 void QFormLayout::insertRow(int row, QWidget *label, QLayout *field)
 {
     Q_D(QFormLayout);
+    if ((label && !d->checkWidget(label)) || (field && !d->checkLayout(field)))
+        return;
 
     row = d->insertRow(row);
     if (label)
@@ -1313,6 +1317,10 @@ void QFormLayout::insertRow(int row, QWidget *label, QLayout *field)
 */
 void QFormLayout::insertRow(int row, const QString &labelText, QWidget *field)
 {
+    Q_D(QFormLayout);
+    if (field && !d->checkWidget(field))
+        return;
+
     QLabel *label = 0;
     if (!labelText.isEmpty()) {
         label = new QLabel(labelText);
@@ -1331,6 +1339,10 @@ void QFormLayout::insertRow(int row, const QString &labelText, QWidget *field)
 */
 void QFormLayout::insertRow(int row, const QString &labelText, QLayout *field)
 {
+    Q_D(QFormLayout);
+    if (field && !d->checkLayout(field))
+        return;
+
     insertRow(row, labelText.isEmpty() ? 0 : new QLabel(labelText), field);
 }
 
@@ -1344,11 +1356,8 @@ void QFormLayout::insertRow(int row, const QString &labelText, QLayout *field)
 void QFormLayout::insertRow(int row, QWidget *widget)
 {
     Q_D(QFormLayout);
-
-    if (!widget) {
-        qWarning("QFormLayout: Cannot add null field to %s", qPrintable(objectName()));
+    if (!d->checkWidget(widget))
         return;
-    }
 
     row = d->insertRow(row);
     d->setWidget(row, SpanningRole, widget);
@@ -1365,11 +1374,8 @@ void QFormLayout::insertRow(int row, QWidget *widget)
 void QFormLayout::insertRow(int row, QLayout *layout)
 {
     Q_D(QFormLayout);
-
-    if (!layout) {
-        qWarning("QFormLayout: Cannot add null field to %s", qPrintable(objectName()));
+    if (!d->checkLayout(layout))
         return;
-    }
 
     row = d->insertRow(row);
     d->setLayout(row, SpanningRole, layout);
diff --git a/src/widgets/kernel/qgridlayout.cpp b/src/widgets/kernel/qgridlayout.cpp
index 5434c40f97..6782e4a9f8 100644
--- a/src/widgets/kernel/qgridlayout.cpp
+++ b/src/widgets/kernel/qgridlayout.cpp
@@ -1430,20 +1430,6 @@ void QGridLayout::addItem(QLayoutItem *item, int row, int column, int rowSpan, i
     invalidate();
 }
 
-/*
-  Returns \c true if the widget \a w can be added to the layout \a l;
-  otherwise returns \c false.
-*/
-static bool checkWidget(QLayout *l, QWidget *w)
-{
-    if (!w) {
-        qWarning("QLayout: Cannot add null widget to %s/%s", l->metaObject()->className(),
-                  l->objectName().toLocal8Bit().data());
-        return false;
-    }
-    return true;
-}
-
 /*!
     Adds the given \a widget to the cell grid at \a row, \a column. The
     top-left position is (0, 0) by default.
@@ -1454,7 +1440,8 @@ static bool checkWidget(QLayout *l, QWidget *w)
 */
 void QGridLayout::addWidget(QWidget *widget, int row, int column, Qt::Alignment alignment)
 {
-    if (!checkWidget(this, widget))
+    Q_D(QGridLayout);
+    if (!d->checkWidget(widget))
         return;
     if (row < 0 || column < 0) {
         qWarning("QGridLayout: Cannot add %s/%s to %s/%s at row %d column %d",
@@ -1483,7 +1470,7 @@ void QGridLayout::addWidget(QWidget *widget, int fromRow, int fromColumn,
                             int rowSpan, int columnSpan, Qt::Alignment alignment)
 {
     Q_D(QGridLayout);
-    if (!checkWidget(this, widget))
+    if (!d->checkWidget(widget))
         return;
     int toRow = (rowSpan < 0) ? -1 : fromRow + rowSpan - 1;
     int toColumn = (columnSpan < 0) ? -1 : fromColumn + columnSpan - 1;
@@ -1518,6 +1505,8 @@ void QGridLayout::addWidget(QWidget *widget, int fromRow, int fromColumn,
 void QGridLayout::addLayout(QLayout *layout, int row, int column, Qt::Alignment alignment)
 {
     Q_D(QGridLayout);
+    if (!d->checkLayout(layout))
+        return;
     if (!adoptLayout(layout))
         return;
     QGridBox *b = new QGridBox(layout);
@@ -1538,6 +1527,8 @@ void QGridLayout::addLayout(QLayout *layout, int row, int column,
                                       int rowSpan, int columnSpan, Qt::Alignment alignment)
 {
     Q_D(QGridLayout);
+    if (!d->checkLayout(layout))
+        return;
     if (!adoptLayout(layout))
         return;
     QGridBox *b = new QGridBox(layout);
diff --git a/src/widgets/kernel/qlayout.cpp b/src/widgets/kernel/qlayout.cpp
index eb21a580b1..778514f47a 100644
--- a/src/widgets/kernel/qlayout.cpp
+++ b/src/widgets/kernel/qlayout.cpp
@@ -857,6 +857,47 @@ void QLayoutPrivate::reparentChildWidgets(QWidget *mw)
     }
 }
 
+/*!
+    Returns \c true if the \a widget can be added to the \a layout;
+    otherwise returns \c false.
+*/
+bool QLayoutPrivate::checkWidget(QWidget *widget) const
+{
+    Q_Q(const QLayout);
+    if (!widget) {
+        qWarning("QLayout: Cannot add a null widget to %s/%s", q->metaObject()->className(),
+                  qPrintable(q->objectName()));
+        return false;
+    }
+    if (widget == q->parentWidget()) {
+        qWarning("QLayout: Cannot add parent widget %s/%s to its child layout %s/%s",
+                  widget->metaObject()->className(), qPrintable(widget->objectName()),
+                  q->metaObject()->className(), qPrintable(q->objectName()));
+        return false;
+    }
+    return true;
+}
+
+/*!
+    Returns \c true if the \a otherLayout can be added to the \a layout;
+    otherwise returns \c false.
+*/
+bool QLayoutPrivate::checkLayout(QLayout *otherLayout) const
+{
+    Q_Q(const QLayout);
+    if (!otherLayout) {
+        qWarning("QLayout: Cannot add a null layout to %s/%s", q->metaObject()->className(),
+                  qPrintable(q->objectName()));
+        return false;
+    }
+    if (otherLayout == q) {
+        qWarning("QLayout: Cannot add layout %s/%s to itself", q->metaObject()->className(),
+                  qPrintable(q->objectName()));
+        return false;
+    }
+    return true;
+}
+
 /*!
     This function is called from \c addWidget() functions in
     subclasses to add \a w as a managed widget of a layout.
diff --git a/src/widgets/kernel/qlayout_p.h b/src/widgets/kernel/qlayout_p.h
index 2100d86aba..71e0f9bcd3 100644
--- a/src/widgets/kernel/qlayout_p.h
+++ b/src/widgets/kernel/qlayout_p.h
@@ -76,6 +76,8 @@ public:
     void getMargin(int *result, int userMargin, QStyle::PixelMetric pm) const;
     void doResize(const QSize &);
     void reparentChildWidgets(QWidget *mw);
+    bool checkWidget(QWidget *widget) const;
+    bool checkLayout(QLayout *otherLayout) const;
 
     static QWidgetItem *createWidgetItem(const QLayout *layout, QWidget *widget);
     static QSpacerItem *createSpacerItem(const QLayout *layout, int w, int h, QSizePolicy::Policy hPolicy = QSizePolicy::Minimum, QSizePolicy::Policy vPolicy = QSizePolicy::Minimum);
diff --git a/tests/auto/widgets/kernel/qboxlayout/tst_qboxlayout.cpp b/tests/auto/widgets/kernel/qboxlayout/tst_qboxlayout.cpp
index 850bedd9cc..4167d633b0 100644
--- a/tests/auto/widgets/kernel/qboxlayout/tst_qboxlayout.cpp
+++ b/tests/auto/widgets/kernel/qboxlayout/tst_qboxlayout.cpp
@@ -79,6 +79,8 @@ private slots:
 
     void taskQTBUG_7103_minMaxWidthNotRespected();
     void taskQTBUG_27420_takeAtShouldUnparentLayout();
+    void taskQTBUG_40609_addingWidgetToItsOwnLayout();
+    void taskQTBUG_40609_addingLayoutToItself();
     void replaceWidget();
 };
 
@@ -329,6 +331,36 @@ void tst_QBoxLayout::taskQTBUG_27420_takeAtShouldUnparentLayout()
         QVERIFY(!inner.isNull());
 }
 
+void tst_QBoxLayout::taskQTBUG_40609_addingWidgetToItsOwnLayout(){
+    QWidget widget;
+    widget.setObjectName("347b469225a24a0ef05150a");
+    QVBoxLayout layout(&widget);
+    layout.setObjectName("ef9e2b42298e0e6420105bb");
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add a null widget to QVBoxLayout/ef9e2b42298e0e6420105bb");
+    layout.addWidget(Q_NULLPTR);
+    QCOMPARE(layout.count(), 0);
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add parent widget QWidget/347b469225a24a0ef05150a to its child layout QVBoxLayout/ef9e2b42298e0e6420105bb");
+    layout.addWidget(&widget);
+    QCOMPARE(layout.count(), 0);
+}
+
+void tst_QBoxLayout::taskQTBUG_40609_addingLayoutToItself(){
+    QWidget widget;
+    widget.setObjectName("fe44e5cb6c08006597126a");
+    QVBoxLayout layout(&widget);
+    layout.setObjectName("cc751dd0f50f62b05a62da");
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add a null layout to QVBoxLayout/cc751dd0f50f62b05a62da");
+    layout.addLayout(Q_NULLPTR);
+    QCOMPARE(layout.count(), 0);
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add layout QVBoxLayout/cc751dd0f50f62b05a62da to itself");
+    layout.addLayout(&layout);
+    QCOMPARE(layout.count(), 0);
+}
+
 struct Descr
 {
     Descr(int min, int sh, int max = -1, bool exp= false, int _stretch = 0, bool _empty = false)
diff --git a/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp b/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp
index 9df7e1662d..962e472606 100644
--- a/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp
+++ b/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp
@@ -135,6 +135,8 @@ private slots:
 */
 
     void taskQTBUG_27420_takeAtShouldUnparentLayout();
+    void taskQTBUG_40609_addingWidgetToItsOwnLayout();
+    void taskQTBUG_40609_addingLayoutToItself();
 
 };
 
@@ -949,6 +951,28 @@ void tst_QFormLayout::taskQTBUG_27420_takeAtShouldUnparentLayout()
         QVERIFY(!inner.isNull());
 }
 
+void tst_QFormLayout::taskQTBUG_40609_addingWidgetToItsOwnLayout(){
+    QWidget widget;
+    widget.setObjectName("6435cbada60548b4522cbb6");
+    QFormLayout layout(&widget);
+    layout.setObjectName("c03c0e22c0b6d019a93a248");
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add parent widget QWidget/6435cbada60548b4522cbb6 to its child layout QFormLayout/c03c0e22c0b6d019a93a248");
+    layout.addRow(QLatin1String("48c81f39b7320082f8"), &widget);
+    QCOMPARE(layout.count(), 0);
+}
+
+void tst_QFormLayout::taskQTBUG_40609_addingLayoutToItself(){
+    QWidget widget;
+    widget.setObjectName("2bc425637d084c07ce65956");
+    QFormLayout layout(&widget);
+    layout.setObjectName("60e31de0c8800eaba713a4f2");
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add layout QFormLayout/60e31de0c8800eaba713a4f2 to itself");
+    layout.addRow(QLatin1String("9a2cd4f40c06b489f889"), &layout);
+    QCOMPARE(layout.count(), 0);
+}
+
 void tst_QFormLayout::replaceWidget()
 {
     QWidget w;
diff --git a/tests/auto/widgets/kernel/qgridlayout/tst_qgridlayout.cpp b/tests/auto/widgets/kernel/qgridlayout/tst_qgridlayout.cpp
index 3b7c2ac14d..0dcae2fbcc 100644
--- a/tests/auto/widgets/kernel/qgridlayout/tst_qgridlayout.cpp
+++ b/tests/auto/widgets/kernel/qgridlayout/tst_qgridlayout.cpp
@@ -101,6 +101,8 @@ private slots:
     void distributeMultiCell();
 
     void taskQTBUG_27420_takeAtShouldUnparentLayout();
+    void taskQTBUG_40609_addingWidgetToItsOwnLayout();
+    void taskQTBUG_40609_addingLayoutToItself();
     void replaceWidget();
 
 private:
@@ -1660,6 +1662,36 @@ void tst_QGridLayout::taskQTBUG_27420_takeAtShouldUnparentLayout()
         QVERIFY(!inner.isNull());
 }
 
+void tst_QGridLayout::taskQTBUG_40609_addingWidgetToItsOwnLayout(){
+    QWidget widget;
+    widget.setObjectName("9bb37ca762aeb7269b8");
+    QGridLayout layout(&widget);
+    layout.setObjectName("d631e91a35f2b66a6dff35");
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add a null widget to QGridLayout/d631e91a35f2b66a6dff35");
+    layout.addWidget(Q_NULLPTR, 0, 0);
+    QCOMPARE(layout.count(), 0);
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add parent widget QWidget/9bb37ca762aeb7269b8 to its child layout QGridLayout/d631e91a35f2b66a6dff35");
+    layout.addWidget(&widget, 0, 0);
+    QCOMPARE(layout.count(), 0);
+}
+
+void tst_QGridLayout::taskQTBUG_40609_addingLayoutToItself(){
+    QWidget widget;
+    widget.setObjectName("0373d417fffe2c59c6fe543");
+    QGridLayout layout(&widget);
+    layout.setObjectName("5d79e1b0aed83f100e3c2");
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add a null layout to QGridLayout/5d79e1b0aed83f100e3c2");
+    layout.addLayout(Q_NULLPTR, 0, 0);
+    QCOMPARE(layout.count(), 0);
+
+    QTest::ignoreMessage(QtWarningMsg, "QLayout: Cannot add layout QGridLayout/5d79e1b0aed83f100e3c2 to itself");
+    layout.addLayout(&layout, 0, 0);
+    QCOMPARE(layout.count(), 0);
+}
+
 void tst_QGridLayout::replaceWidget()
 {
     QWidget wdg;
diff --git a/tests/manual/qlayout/gridwidget.cpp b/tests/manual/qlayout/gridwidget.cpp
index 31f0094182..6d7de3c763 100644
--- a/tests/manual/qlayout/gridwidget.cpp
+++ b/tests/manual/qlayout/gridwidget.cpp
@@ -53,6 +53,7 @@ GridWidget::GridWidget(QWidget *parent) :
     QWidget(parent)
 {
     QGridLayout *hb = new QGridLayout(this);
+    hb->setObjectName("GridWidget");
     QComboBox *combo = new QComboBox();
     combo->addItem("123");
     QComboBox *combo2 = new QComboBox();
@@ -71,4 +72,11 @@ GridWidget::GridWidget(QWidget *parent) :
     hb->addWidget(new QPushButton("123"), 1, 4);
     hb->addWidget(new QSpinBox(), 0, 5);
     hb->addWidget(new QSpinBox(), 1, 5);
+
+    qDebug("There should be four warnings, but no crash or freeze:");
+    hb->addWidget(this, 6, 6); ///< This command should print a warning, but should not add "this"
+    hb->addWidget(Q_NULLPTR, 6, 7); ///< This command should print a warning, but should not add "NULL"
+    hb->addLayout(hb, 7, 6); ///< This command should print a warning, but should not add "hb"
+    hb->addLayout(Q_NULLPTR, 7, 7); ///< This command should print a warning, but should not add "NULL"
+    qDebug("Neither crashed nor frozen");
 }
diff --git a/tests/manual/qlayout/hbwidget.cpp b/tests/manual/qlayout/hbwidget.cpp
index e8bb07f4a4..743b420b0d 100644
--- a/tests/manual/qlayout/hbwidget.cpp
+++ b/tests/manual/qlayout/hbwidget.cpp
@@ -53,6 +53,7 @@ HbWidget::HbWidget(QWidget *parent) :
     QWidget(parent)
 {
     QHBoxLayout *hb = new QHBoxLayout(this);
+    hb->setObjectName("HbWidget");
     QComboBox *combo = new QComboBox(this);
     combo->addItem("123");
     QComboBox *combo2 = new QComboBox();
@@ -67,4 +68,11 @@ HbWidget::HbWidget(QWidget *parent) :
     hb->addWidget(new QDateTimeEdit());
     hb->addWidget(new QPushButton("123"));
     hb->addWidget(new QSpinBox());
+
+    qDebug("There should be four warnings, but no crash or freeze:");
+    hb->addWidget(this); ///< This command should print a warning, but should not add "this"
+    hb->addWidget(Q_NULLPTR); ///< This command should print a warning, but should not add "NULL"
+    hb->addLayout(hb); ///< This command should print a warning, but should not add "hb"
+    hb->addLayout(Q_NULLPTR); ///< This command should print a warning, but should not add "NULL"
+    qDebug("Neither crashed nor frozen");
 }
diff --git a/tests/manual/qlayout/vbwidget.cpp b/tests/manual/qlayout/vbwidget.cpp
index 063176625d..ffd918b955 100644
--- a/tests/manual/qlayout/vbwidget.cpp
+++ b/tests/manual/qlayout/vbwidget.cpp
@@ -53,6 +53,7 @@ VbWidget::VbWidget(QWidget *parent) :
     QWidget(parent)
 {
     QVBoxLayout *hb = new QVBoxLayout(this);
+    hb->setObjectName("VbWidget");
     QComboBox *combo = new QComboBox(this);
     combo->addItem("123");
     QComboBox *combo2 = new QComboBox();
@@ -67,4 +68,11 @@ VbWidget::VbWidget(QWidget *parent) :
     hb->addWidget(new QDateTimeEdit());
     hb->addWidget(new QPushButton("123"));
     hb->addWidget(new QSpinBox());
+
+    qDebug("There should be four warnings, but no crash or freeze:");
+    hb->addWidget(this); ///< This command should print a warning, but should not add "this"
+    hb->addWidget(Q_NULLPTR); ///< This command should print a warning, but should not add "NULL"
+    hb->addLayout(hb); ///< This command should print a warning, but should not add "hb"
+    hb->addLayout(Q_NULLPTR); ///< This command should print a warning, but should not add "NULL"
+    qDebug("Neither crashed nor frozen");
 }