Fix -Wimplicit-fallthrough for clang

Clang's `-Wimplicit-fallthrough` warnings are a little stricter than
gcc's interpretation:

switch (i) {
case 0:
    foo();
case 4:
    break;
}

While gcc accepts the implicit fallthrough, if the following statement
is a trivial `break`, clang will warn about it.

Change-Id: I38e0817f1bc034fbb552aeac21de1516edcbcbb0
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit c26994ff1551aa5450383cc51bed9b4d39f973f7)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/3rdparty/tinycbor/src/cborparser.c

@@ -232,7 +232,7 @@ static CborError preparse_value(CborValue *it)
         case SinglePrecisionFloat:
         case DoublePrecisionFloat:
             it->flags |= CborIteratorFlag_IntegerValueTooLarge;
-            /* fall through */
+            Q_FALLTHROUGH();
         case TrueValue:
         case NullValue:
         case UndefinedValue:

src/corelib/text/qunicodetools.cpp

@@ -1355,6 +1355,7 @@ static qsizetype indic_nextSyllableBoundary(QChar::Script script, const char16_t
                 // ### needs proper testing for correct two/three part matras
                 break;
             }
+            Q_FALLTHROUGH();
         case IndependentVowel:
         case Invalid:
         case Other:

src/corelib/time/qdatetimeparser.cpp

@@ -709,6 +709,7 @@ int QDateTimeParser::sectionMaxSize(Section s, int count) const
     case DaySectionMask:
         qWarning("QDateTimeParser::sectionMaxSize: Invalid section %s",
                  SectionNode::name(s).toLatin1().constData());
+        break;
 
     case NoSectionIndex:
     case FirstSectionIndex:

src/gui/kernel/qguiapplication.cpp

@@ -2027,6 +2027,7 @@ bool QGuiApplication::event(QEvent *e)
                 return true;
             }
         }
+        break;
     default:
         break;
     }

src/gui/painting/qcssutil.cpp

@@ -268,6 +268,7 @@ void qDrawEdge(QPainter *p, qreal x1, qreal y1, qreal x2, qreal y2, qreal dw1, q
         default:
             break;
         }
+        break;
     }
     default:
         break;

src/gui/text/qfontengine.cpp

@@ -1234,6 +1234,7 @@ const uchar *QFontEngine::getCMap(const uchar *table, uint tableSize, bool *isSy
             default:
                 break;
             }
+            break;
         default:
             break;
         }

src/network/access/http2/http2frames.cpp

@@ -135,6 +135,7 @@ FrameStatus Frame::validateHeader() const
         // 6.6 PUSH_PROMISE
         if (framePayloadSize < 4)
             return FrameStatus::sizeError;
+        break;
     default:
         // DATA/HEADERS/CONTINUATION will be verified
         // when we have payload.

src/network/socket/qnativesocketengine_unix.cpp

@@ -436,6 +436,7 @@ bool QNativeSocketEnginePrivate::nativeConnect(const QHostAddress &addr, quint16
         case EFAULT:
         case ENOTSOCK:
             socketState = QAbstractSocket::UnconnectedState;
+            break;
         default:
             break;
         }

src/platformsupport/input/evdevtouch/qevdevtouchhandler.cpp

@@ -194,6 +194,7 @@ QEvdevTouchScreenHandler::QEvdevTouchScreenHandler(const QString &device, const
                 case 180:
                 case 270:
                     rotationAngle = argValue;
+                    break;
                 default:
                     break;
                 }

src/plugins/generic/tuiotouch/qtuiohandler.cpp

@@ -59,6 +59,7 @@ QTuioHandler::QTuioHandler(const QString &specification)
             case 180:
             case 270:
                 rotationAngle = argValue;
+                break;
             default:
                 break;
             }

src/plugins/imageformats/jpeg/qjpeghandler.cpp

@@ -1146,6 +1146,7 @@ void QJpegHandler::setOption(ImageOption option, const QVariant &value)
         int transformation = value.toInt();
         if (transformation > 0 && transformation < 8)
             d->transformation = QImageIOHandler::Transformations(transformation);
+        break;
     }
     default:
         break;

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -135,6 +135,7 @@ void QXcbWindow::setImageFormatForVisual(const xcb_visualtype_t *visual)
     case 16:
         qWarning("Using RGB16 fallback, if this works your X11 server is reporting a bad screen format.");
         m_imageFormat = QImage::Format_RGB16;
+        break;
     default:
         break;
     }

src/widgets/accessible/itemviews.cpp

@@ -352,6 +352,7 @@ bool QAccessibleTable::unselectRow(int row)
             //the ones which are down the current row will be deselected
             selection = QItemSelection(index, theModel->index(rowCount() - 1, 0, rootIndex));
         }
+        break;
     default:
         break;
     }
@@ -392,6 +393,7 @@ bool QAccessibleTable::unselectColumn(int column)
             //of the current rown, the ones which are at the right will be deselected
             selection = QItemSelection(index, theModel->index(0, columnCount() - 1, rootIndex));
         }
+        break;
     default:
         break;
     }

src/widgets/dialogs/qmessagebox.cpp

@@ -2768,6 +2768,7 @@ QPixmap QMessageBoxPrivate::standardIcon(QMessageBox::Icon icon, QMessageBox *mb
         break;
     case QMessageBox::Question:
         tmpIcon = style->standardIcon(QStyle::SP_MessageBoxQuestion, nullptr, mb);
+        break;
     default:
         break;
     }

src/widgets/graphicsview/qgraphicsscene.cpp

@@ -3253,6 +3253,7 @@ bool QGraphicsScene::event(QEvent *event)
         // ### this should only be cleared if we received a new mouse move event,
         // which relies on us fixing the replay mechanism in QGraphicsView.
         d->cachedItemsUnderMouse.clear();
+        break;
     default:
         break;
     }

src/widgets/itemviews/qabstractitemview.cpp

@@ -4301,6 +4301,7 @@ QItemSelectionModel::SelectionFlags QAbstractItemViewPrivate::extendedSelectionC
             default:
                 break;
             }
+            break;
         }
         default:
             break;

src/widgets/kernel/qapplication.cpp

@@ -2645,6 +2645,7 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
         Q_FALLTHROUGH();
     case QEvent::Leave:
         d->toolTipWakeUp.stop();
+        break;
     default:
         break;
     }
@@ -2669,6 +2670,7 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
                     || key == Qt::Key_Up
                     || key == Qt::Key_Right
                     || key == Qt::Key_Down);
+        break;
     }
     default:
         break;

src/widgets/kernel/qtooltip.cpp

@@ -329,6 +329,7 @@ bool QTipLabel::eventFilter(QObject *o, QEvent *e)
     case QEvent::MouseMove:
         if (o == widget && !rect.isNull() && !rect.contains(static_cast<QMouseEvent*>(e)->position().toPoint()))
             hideTip();
+        break;
     default:
         break;
     }

src/widgets/styles/qcommonstyle.cpp

@@ -4224,6 +4224,7 @@ QRect QCommonStyle::subControlRect(ComplexControl cc, const QStyleOptionComplex
                 break;
             case SC_SpinBoxFrame:
                 ret = spinbox->rect;
+                break;
             default:
                 break;
             }

src/widgets/styles/qfusionstyle.cpp

@@ -3309,6 +3309,7 @@ QRect QFusionStyle::subControlRect(ComplexControl control, const QStyleOptionCom
                 break;
             case SC_SpinBoxFrame:
                 rect = spinbox->rect;
+                break;
             default:
                 break;
             }

src/widgets/styles/qstyleanimation.cpp

@@ -256,6 +256,7 @@ static QImage blendedImage(const QImage &start, const QImage &end, float alpha)
                 front_data += bpl;
             }
         }
+        break;
     default:
         break;
     }

src/widgets/styles/qstylesheetstyle.cpp

@@ -4871,6 +4871,7 @@ void QStyleSheetStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *op
             w = w->parentWidget(); //match on the QTabBar instead of the CloseButton
         }
         pseudoElement = PseudoElement_TabBarTabCloseButton;
+        break;
 #endif
 
     default:

src/widgets/widgets/qabstractspinbox.cpp

@@ -2043,6 +2043,7 @@ QVariant operator-(const QVariant &arg1, const QVariant &arg2)
                 dt.setTime(dt.time().addMSecs(msecs));
             ret = QVariant(dt);
         }
+        break;
     }
     default: break;
     }

src/widgets/widgets/qcalendarwidget.cpp

@@ -3099,6 +3099,7 @@ bool QCalendarWidget::event(QEvent *event)
         case QEvent::StyleChange:
             d->cachedSizeHint = QSize();
             d->m_view->updateGeometry();
+            break;
         default:
             break;
     }

src/widgets/widgets/qdatetimeedit.cpp

@@ -1331,6 +1331,7 @@ void QDateTimeEdit::focusInEvent(QFocusEvent *event)
     case Qt::ActiveWindowFocusReason:
         if (oldHasHadFocus)
             return;
+        break;
     case Qt::ShortcutFocusReason:
     case Qt::TabFocusReason:
     default:

src/widgets/widgets/qeffects.cpp

@@ -292,6 +292,7 @@ void QAlphaWidget::alphaBlend()
                 back_data += bpl;
                 front_data += bpl;
             }
+            break;
         }
     default:
         break;

src/widgets/widgets/qmainwindowlayout.cpp

@@ -338,6 +338,7 @@ bool QDockWidgetGroupWindow::event(QEvent *e)
     case QEvent::Resize:
         updateCurrentGapRect();
         emit resized();
+        break;
     default:
         break;
     }

src/widgets/widgets/qtoolbar.cpp

@@ -1084,6 +1084,7 @@ bool QToolBar::event(QEvent *event)
             d->layout->setExpanded(false);
             break;
         }
+        break;
     default:
         break;
     }

src/widgets/widgets/qwidgetlinecontrol.cpp

@@ -1638,6 +1638,7 @@ void QWidgetLineControl::processKeyEvent(QKeyEvent* event)
                     setText(m_completer->currentCompletion());
                     inlineCompletionAccepted = true;
                 }
+                break;
             default:
                 break; // normal key processing
             }