Support C++17 fallthrough attribute

Replaces our mix of comments for annotating intended absence of break
in switches with the C++17 attribute [[fallthrough]], or its earlier
a clang extension counterpart.

Change-Id: I4b2d0b9b5e4425819c7f1bf01608093c536b6d14
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

6 files changed, 10 insertions, 9 deletions

diff --git a/src/plugins/bearer/qnetworksession_impl.cpp b/src/plugins/bearer/qnetworksession_impl.cpp
index 426cca139d..85942b56f1 100644
--- a/src/plugins/bearer/qnetworksession_impl.cpp
+++ b/src/plugins/bearer/qnetworksession_impl.cpp
@@ -111,10 +111,10 @@ void QNetworkSessionPrivateImpl::syncStateWithInterface()
     case QNetworkConfiguration::ServiceNetwork:
         serviceConfig = publicConfig;
         // Defer setting engine and signals until open().
-        // fall through
+        Q_FALLTHROUGH();
     case QNetworkConfiguration::UserChoice:
         // Defer setting serviceConfig and activeConfig until open().
-        // fall through
+        Q_FALLTHROUGH();
     default:
         engine = 0;
     }
diff --git a/src/plugins/platforms/android/qandroidplatformtheme.cpp b/src/plugins/platforms/android/qandroidplatformtheme.cpp
index 3949113240..b9009fe704 100644
--- a/src/plugins/platforms/android/qandroidplatformtheme.cpp
+++ b/src/plugins/platforms/android/qandroidplatformtheme.cpp
@@ -489,7 +489,7 @@ QVariant QAndroidPlatformTheme::themeHint(ThemeHint hint) const
             if (ret > 0)
                 return ret;
 
-            // fall through
+            Q_FALLTHROUGH();
     }
     default:
         return QPlatformTheme::themeHint(hint);
diff --git a/src/plugins/platforms/cocoa/qprintengine_mac.mm b/src/plugins/platforms/cocoa/qprintengine_mac.mm
index 3d0c91c36c..0b5b06c44f 100644
--- a/src/plugins/platforms/cocoa/qprintengine_mac.mm
+++ b/src/plugins/platforms/cocoa/qprintengine_mac.mm
@@ -200,7 +200,7 @@ int QMacPrintEngine::metric(QPaintDevice::PaintDeviceMetric m) const
             val = (int)resolution.vRes;
             break;
         }
-        //otherwise fall through
+        Q_FALLTHROUGH();
     }
     case QPaintDevice::PdmDpiY:
         val = (int)d->resolution.vRes;
diff --git a/src/plugins/platforms/direct2d/qwindowsdirect2dpaintengine.cpp b/src/plugins/platforms/direct2d/qwindowsdirect2dpaintengine.cpp
index 730d5de450..0ea2fcfa74 100644
--- a/src/plugins/platforms/direct2d/qwindowsdirect2dpaintengine.cpp
+++ b/src/plugins/platforms/direct2d/qwindowsdirect2dpaintengine.cpp
@@ -563,7 +563,7 @@ public:
             if (newPen.widthF() <= 1.0)
                 props.startCap = props.endCap = props.dashCap = D2D1_CAP_STYLE_FLAT;
 
-            // fall through
+            Q_FALLTHROUGH();
         default:
             props.dashStyle = D2D1_DASH_STYLE_CUSTOM;
             break;
diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 3a683bd7a0..d4cdf3ef3c 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -945,7 +945,8 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
     switch (et) {
     case QtWindows::KeyboardLayoutChangeEvent:
         if (QWindowsInputContext *wic = windowsInputContext())
-            wic->handleInputLanguageChanged(wParam, lParam); // fallthrough intended.
+            wic->handleInputLanguageChanged(wParam, lParam);
+        Q_FALLTHROUGH();
     case QtWindows::KeyDownEvent:
     case QtWindows::KeyEvent:
     case QtWindows::InputMethodKeyEvent:
diff --git a/src/plugins/platforms/windows/qwindowstheme.cpp b/src/plugins/platforms/windows/qwindowstheme.cpp
index 79befc56c2..841464391d 100644
--- a/src/plugins/platforms/windows/qwindowstheme.cpp
+++ b/src/plugins/platforms/windows/qwindowstheme.cpp
@@ -551,14 +551,14 @@ QPixmap QWindowsTheme::standardPixmap(StandardPixmap sp, const QSizeF &pixmapSiz
         break;
     case FileLinkIcon:
         stockFlags = SHGSI_LINKOVERLAY;
-        // Fall through
+        Q_FALLTHROUGH();
     case FileIcon:
         stockId = SIID_DOCNOASSOC;
         resourceId = 1;
         break;
     case DirLinkIcon:
         stockFlags = SHGSI_LINKOVERLAY;
-        // Fall through
+        Q_FALLTHROUGH();
     case DirClosedIcon:
     case DirIcon:
         stockId = SIID_FOLDER;
@@ -572,7 +572,7 @@ QPixmap QWindowsTheme::standardPixmap(StandardPixmap sp, const QSizeF &pixmapSiz
         break;
     case DirLinkOpenIcon:
         stockFlags = SHGSI_LINKOVERLAY;
-        // Fall through
+        Q_FALLTHROUGH();
     case DirOpenIcon:
         stockId = SIID_FOLDEROPEN;
         resourceId = 5;