diff --git a/src/AutoPilotPlugins/APM/APMSensorsComponentController.cc b/src/AutoPilotPlugins/APM/APMSensorsComponentController.cc
index 1d45eb05abbbb949b9489ab5e723147db7f5eb36..14d54704aed17aa4a9c2bea791df56193c1daa3c 100644
--- a/src/AutoPilotPlugins/APM/APMSensorsComponentController.cc
+++ b/src/AutoPilotPlugins/APM/APMSensorsComponentController.cc
@@ -782,7 +782,7 @@ void APMSensorsComponentController::_handleMagCalProgress(mavlink_message_t& mes
             }
         }
 
-        if (magCalProgress.compass_id < 3) {
+        if (magCalProgress.compass_id < 3 && compassCalCount != 0) {
             // Each compass gets a portion of the overall progress
             _rgCompassCalProgress[magCalProgress.compass_id] = magCalProgress.completion_pct / compassCalCount;
         }
diff --git a/src/AutoPilotPlugins/AutoPilotPlugin.cc b/src/AutoPilotPlugins/AutoPilotPlugin.cc
index 4da3426b1da4ff4beb842423b2fadeae32852c96..40fd4713abe8d820e8d15efc2773b5fa66c841f5 100644
--- a/src/AutoPilotPlugins/AutoPilotPlugin.cc
+++ b/src/AutoPilotPlugins/AutoPilotPlugin.cc
@@ -33,7 +33,7 @@ void AutoPilotPlugin::_recalcSetupComplete(void)
 {
     bool newSetupComplete = true;
 
-    for(const QVariant componentVariant: vehicleComponents()) {
+    for(const QVariant& componentVariant: vehicleComponents()) {
         VehicleComponent* component = qobject_cast<VehicleComponent*>(qvariant_cast<QObject *>(componentVariant));
         if (component) {
             if (!component->setupComplete()) {
diff --git a/src/Camera/QGCCameraControl.cc b/src/Camera/QGCCameraControl.cc
index f7aab027bc6816caec39d800c9692e9933c26826..a457204db21938dc9b2d02217024616a95627de4 100644
--- a/src/Camera/QGCCameraControl.cc
+++ b/src/Camera/QGCCameraControl.cc
@@ -1153,7 +1153,7 @@ void
 QGCCameraControl::_requestAllParameters()
 {
     //-- Reset receive list
-    for(QString paramName: _paramIO.keys()) {
+    for(const QString& paramName: _paramIO.keys()) {
         if(_paramIO[paramName]) {
             _paramIO[paramName]->setParamRequest();
         } else {
@@ -1391,7 +1391,7 @@ QGCCameraControl::_updateRanges(Fact* pFact)
     }
     //-- Parameter update requests
     if(_requestUpdates.contains(pFact->name())) {
-        for(QString param: _requestUpdates[pFact->name()]) {
+        for(const QString& param: _requestUpdates[pFact->name()]) {
             if(!_updatesToRequest.contains(param)) {
                 _updatesToRequest << param;
             }
@@ -1406,7 +1406,7 @@ QGCCameraControl::_updateRanges(Fact* pFact)
 void
 QGCCameraControl::_requestParamUpdates()
 {
-    for(QString param: _updatesToRequest) {
+    for(const QString& param: _updatesToRequest) {
         _paramIO[param]->paramRequest();
     }
     _updatesToRequest.clear();
@@ -1831,7 +1831,6 @@ QGCCameraControl::_loadRanges(QDomNode option, const QString factName, QString p
         for(int i = 0; i < parameterRanges.size(); i++) {
             QString param;
             QString condition;
-            QMap<QString, QVariant> rangeList;
             QDomNode paramRange = parameterRanges.item(i);
             if(!read_attribute(paramRange, kParameter, param)) {
                 qCritical() << QString("Malformed option range for parameter %1").arg(factName);
@@ -2003,7 +2002,7 @@ QGCCameraControl::_dataReady(QByteArray data)
 void
 QGCCameraControl::_paramDone()
 {
-    for(QString param: _paramIO.keys()) {
+    for(const QString& param: _paramIO.keys()) {
         if(!_paramIO[param]->paramDone()) {
             return;
         }
diff --git a/src/QtLocationPlugin/QGeoTiledMappingManagerEngineQGC.cpp b/src/QtLocationPlugin/QGeoTiledMappingManagerEngineQGC.cpp
index 51d2f49a30535785a5860f4b87aec24149308eaf..a58fe028caf282116a601c5b2ad450a86f5f9e81 100644
--- a/src/QtLocationPlugin/QGeoTiledMappingManagerEngineQGC.cpp
+++ b/src/QtLocationPlugin/QGeoTiledMappingManagerEngineQGC.cpp
@@ -217,14 +217,14 @@ QGeoTiledMappingManagerEngineQGC::_setCache(const QVariantMap &parameters)
         cacheDir = parameters.value(QStringLiteral("mapping.cache.directory")).toString();
     else {
         cacheDir = getQGCMapEngine()->getCachePath();
-        if(!QFileInfo(cacheDir).exists()) {
+        if(!QFileInfo::exists(cacheDir)) {
             if(!QDir::root().mkpath(cacheDir)) {
                 qWarning() << "Could not create mapping disk cache directory: " << cacheDir;
                 cacheDir = QDir::homePath() + QStringLiteral("/.qgcmapscache/");
             }
         }
     }
-    if(!QFileInfo(cacheDir).exists()) {
+    if(!QFileInfo::exists(cacheDir)) {
         if(!QDir::root().mkpath(cacheDir)) {
             qWarning() << "Could not create mapping disk cache directory: " << cacheDir;
             cacheDir.clear();
diff --git a/src/Terrain/TerrainQuery.cc b/src/Terrain/TerrainQuery.cc
index 52687493587b0036794cd13261c88229b0df612a..4a25d2a0536ec2f960173eb33dd5cead69f0088e 100644
--- a/src/Terrain/TerrainQuery.cc
+++ b/src/Terrain/TerrainQuery.cc
@@ -501,6 +501,7 @@ void TerrainTileManager::_terrainDone(QByteArray responseBytes, QNetworkReply::N
         }
         _tilesMutex.unlock();
     } else {
+        delete terrainTile;
         qCWarning(TerrainQueryLog) << "Received invalid tile";
     }
     reply->deleteLater();
diff --git a/src/VehicleSetup/PX4FirmwareUpgradeThread.cc b/src/VehicleSetup/PX4FirmwareUpgradeThread.cc
index 7b70c2922463f8ad6f562cbd15833553d89f12ee..5da788997b8859c9094b14c630adcbe3b012c36b 100644
--- a/src/VehicleSetup/PX4FirmwareUpgradeThread.cc
+++ b/src/VehicleSetup/PX4FirmwareUpgradeThread.cc
@@ -119,7 +119,7 @@ void PX4FirmwareUpgradeThreadWorker::_findBoardOnce(void)
 
 bool PX4FirmwareUpgradeThreadWorker::_findBoardFromPorts(QGCSerialPortInfo& portInfo, QGCSerialPortInfo::BoardType_t& boardType, QString& boardName)
 {
-    for (QGCSerialPortInfo info: QGCSerialPortInfo::availablePorts()) {
+    for (const QGCSerialPortInfo& info: QGCSerialPortInfo::availablePorts()) {
         info.getBoardInfo(boardType, boardName);
 
         qCDebug(FirmwareUpgradeVerboseLog) << "Serial Port --------------";
diff --git a/src/comm/LinkManager.cc b/src/comm/LinkManager.cc
index 43e46a8c552451544649af01a2f0512caf10c36f..9724cab9c75dd71fa9f0ab81bf6e3bb14c7367a3 100644
--- a/src/comm/LinkManager.cc
+++ b/src/comm/LinkManager.cc
@@ -518,7 +518,7 @@ void LinkManager::_updateAutoConnectLinks(void)
 #endif
 
     // Iterate Comm Ports
-    for (QGCSerialPortInfo portInfo: portList) {
+    for (const QGCSerialPortInfo& portInfo: portList) {
         qCDebug(LinkManagerVerboseLog) << "-----------------------------------------------------";
         qCDebug(LinkManagerVerboseLog) << "portName:          " << portInfo.portName();
         qCDebug(LinkManagerVerboseLog) << "systemLocation:    " << portInfo.systemLocation();
@@ -931,7 +931,7 @@ void LinkManager::_activeLinkCheck(void)
         QSignalSpy spy(link, SIGNAL(bytesReceived(LinkInterface*, QByteArray)));
         if (spy.wait(100)) {
             QList<QVariant> arguments = spy.takeFirst();
-            if (arguments[1].value<QByteArray>().contains("nsh>")) {
+            if (arguments[1].toByteArray().contains("nsh>")) {
                 foundNSHPrompt = true;
             }
         }
diff --git a/src/comm/MAVLinkProtocol.cc b/src/comm/MAVLinkProtocol.cc
index 2d4e08da1c2c571eb1cab8b1c39d956cf19781c9..398b013b9262fa811ad528fb54f466d34bee2fd0 100644
--- a/src/comm/MAVLinkProtocol.cc
+++ b/src/comm/MAVLinkProtocol.cc
@@ -461,7 +461,7 @@ void MAVLinkProtocol::checkForLostLogFiles(void)
     QFileInfoList fileInfoList = tempDir.entryInfoList(QStringList(filter), QDir::Files);
     //qDebug() << "Orphaned log file count" << fileInfoList.count();
 
-    for(const QFileInfo fileInfo: fileInfoList) {
+    for(const QFileInfo& fileInfo: fileInfoList) {
         //qDebug() << "Orphaned log file" << fileInfo.filePath();
         if (fileInfo.size() == 0) {
             // Delete all zero length files
diff --git a/src/comm/UDPLink.cc b/src/comm/UDPLink.cc
index 58fe36da5341d6ac68115be1ee787ec787acc6d9..e24b45885af1a10802dbb37c85247f24b116712a 100644
--- a/src/comm/UDPLink.cc
+++ b/src/comm/UDPLink.cc
@@ -55,7 +55,6 @@ static QString get_ip_address(const QString& address)
     if (info.error() == QHostInfo::NoError)
     {
         QList<QHostAddress> hostAddresses = info.addresses();
-        QHostAddress address;
         for (int i = 0; i < hostAddresses.size(); i++)
         {
             // Exclude all IPv6 addresses