modernize: use [[fallthrough]] instead of Q_FALLTHROUGH

CMakeLists.txt

@@ -147,7 +147,7 @@ add_compile_flag_if_supported(-Wno-missing-field-initializers)
 add_compile_flag_if_supported(-Werror=switch)
 add_compile_flag_if_supported(-Werror=undefined-bool-conversion)
 add_compile_flag_if_supported(-Werror=tautological-undefined-compare)
-add_compile_flag_if_supported(-Werror=implicit-fallthrough)    # Use Q_FALLTHROUGH for false positives.
+add_compile_flag_if_supported(-Werror=implicit-fallthrough)    # Use [[fallthrough]] for false positives.
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     add_compile_flag_if_supported(-Wdocumentation)
     add_compile_flag_if_supported(-Wcovered-switch-default)

kdevplatform/language/duchain/navigation/abstractnavigationcontext.cpp

@@ -194,7 +194,7 @@ NavigationContextPointer AbstractNavigationContext::execute(const NavigationActi
             browser->showUses(action.decl);
             return NavigationContextPointer(this);
         }
-        Q_FALLTHROUGH();
+        [[fallthrough]];
     }
     case NavigationAction::ShowUses: {
         return registerChild(new UsesNavigationContext(action.decl.data(), this));

kdevplatform/language/duchain/stringhelpers.cpp

@@ -125,7 +125,7 @@ int findClose(const QString& str, int pos)
         case '>':
             if (last == QLatin1Char('-'))
                 break;
-            Q_FALLTHROUGH();
+            [[fallthrough]];
         case ')':
         case ']':
         case '}':
@@ -182,7 +182,7 @@ int findCommaOrEnd(const QString& str, int pos, QChar validEnd)
         case '>':
             if (validEnd != QLatin1Char(' ') && validEnd != str[a])
                 continue;
-            Q_FALLTHROUGH();
+            [[fallthrough]];
         case ',':
             return a;
         }

plugins/ghprovider/ghproviderwidget.cpp

@@ -153,7 +153,7 @@ void ProviderWidget::searchRepo()
     case 2: /* Known organization */
         text = m_combo->currentText();
         enabled = false;
-        Q_FALLTHROUGH();
+        [[fallthrough]];
     default:/* Looking for some organization's repo. */
         uri = QStringLiteral("/orgs/%1/repos").arg(text);
         break;

plugins/quickopen/quickopenwidget.cpp

@@ -452,7 +452,7 @@ bool QuickOpenWidget::eventFilter(QObject* watched, QEvent* event)
                 }
                 break;
             }
-            Q_FALLTHROUGH();
+            [[fallthrough]];
         case Qt::Key_PageUp:
         case Qt::Key_PageDown:
             if (watched == ui.list) {