diff --git a/src/app/main.cpp b/src/app/main.cpp
index 5421862db8d1..0684ed852c11 100644
--- a/src/app/main.cpp
+++ b/src/app/main.cpp
@@ -1172,7 +1172,7 @@ int main( int argc, char *argv[] )
     }
     else
     {
-      Q_FOREACH ( QgsMapLayer *ml, QgsMapLayerRegistry::instance()->mapLayers().values() )
+      Q_FOREACH ( QgsMapLayer *ml, QgsMapLayerRegistry::instance()->mapLayers() )
       {
         QgsVectorLayer *vl = qobject_cast<QgsVectorLayer *>( ml );
         if ( !vl )
diff --git a/src/app/nodetool/qgsmaptoolnodetool.cpp b/src/app/nodetool/qgsmaptoolnodetool.cpp
index 27bf53a815e3..d2edb3cae7b7 100644
--- a/src/app/nodetool/qgsmaptoolnodetool.cpp
+++ b/src/app/nodetool/qgsmaptoolnodetool.cpp
@@ -67,7 +67,7 @@ void QgsMapToolNodeTool::createTopologyRubberBands()
     // Snap vertex
     QMultiMap<double, QgsSnappingResult> snapResults;
     vlayer->snapWithContext( vertexEntry->pointV1(), ZERO_TOLERANCE, snapResults, QgsSnapper::SnapToVertex );
-    Q_FOREACH ( const QgsSnappingResult& snapResult, snapResults.values() )
+    Q_FOREACH ( const QgsSnappingResult& snapResult, snapResults )
     {
       // Get geometry of snapped feature
       QgsFeatureId snapFeatureId = snapResult.snappedAtGeometry;
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
index 29494b32dd87..4c4785c08a2c 100644
--- a/src/app/qgisapp.cpp
+++ b/src/app/qgisapp.cpp
@@ -4798,7 +4798,7 @@ bool QgisApp::openLayer( const QString & fileName, bool allowInteractive )
   if ( QgsRasterLayer::isValidRasterFileName( fileName ) )
   {
     // open .adf as a directory
-    if ( fileName.toLower().endsWith( ".adf" ) )
+    if ( fileName.endsWith( ".adf", Qt::CaseInsensitive ) )
     {
       QString dirName = fileInfo.path();
       ok  = addRasterLayer( dirName, QFileInfo( dirName ).completeBaseName() );
@@ -10337,7 +10337,7 @@ QgsRasterLayer* QgisApp::addRasterLayerPrivate(
   // XXX ya know QgsRasterLayer can snip out the basename on its own;
   // XXX why do we have to pass it in for it?
   // ET : we may not be getting "normal" files here, so we still need the baseName argument
-  if ( !providerKey.isEmpty() && uri.toLower().endsWith( ".adf" ) )
+  if ( !providerKey.isEmpty() && uri.endsWith( ".adf", Qt::CaseInsensitive ) )
   {
     QFileInfo fileInfo( uri );
     QString dirName = fileInfo.path();
diff --git a/src/app/qgsalignrasterdialog.cpp b/src/app/qgsalignrasterdialog.cpp
index 53e8b7dfe75a..a86b46ac5b2b 100644
--- a/src/app/qgsalignrasterdialog.cpp
+++ b/src/app/qgsalignrasterdialog.cpp
@@ -36,7 +36,7 @@
 static QgsMapLayer* _rasterLayer( const QString& filename )
 {
   QMap<QString, QgsMapLayer*> layers = QgsMapLayerRegistry::instance()->mapLayers();
-  Q_FOREACH ( QgsMapLayer* layer, layers.values() )
+  Q_FOREACH ( QgsMapLayer* layer, layers )
   {
     if ( layer->type() == QgsMapLayer::RasterLayer && layer->source() == filename )
       return layer;
@@ -457,7 +457,7 @@ void QgsAlignRasterLayerConfigDialog::browseOutputFilename()
   if ( !fileName.isEmpty() )
   {
     // ensure the user never ommited the extension from the file name
-    if ( !fileName.toLower().endsWith( ".tif" ) && !fileName.toLower().endsWith( ".tiff" ) )
+    if ( !fileName.endsWith( ".tif", Qt::CaseInsensitive ) && !fileName.endsWith( ".tiff", Qt::CaseInsensitive ) )
     {
       fileName += ".tif";
     }
diff --git a/src/app/qgsbookmarks.cpp b/src/app/qgsbookmarks.cpp
index 620936a5e715..1715001189ff 100644
--- a/src/app/qgsbookmarks.cpp
+++ b/src/app/qgsbookmarks.cpp
@@ -326,7 +326,7 @@ void QgsBookmarks::exportToXML()
   }
 
   // ensure the user never ommited the extension from the file name
-  if ( !fileName.toLower().endsWith( ".xml" ) )
+  if ( !fileName.endsWith( ".xml", Qt::CaseInsensitive ) )
   {
     fileName += ".xml";
   }
diff --git a/src/app/qgsconfigureshortcutsdialog.cpp b/src/app/qgsconfigureshortcutsdialog.cpp
index 1b8f0193e924..7e37e7ef64d2 100644
--- a/src/app/qgsconfigureshortcutsdialog.cpp
+++ b/src/app/qgsconfigureshortcutsdialog.cpp
@@ -107,7 +107,7 @@ void QgsConfigureShortcutsDialog::saveShortcuts()
     return;
 
   // ensure the user never omitted the extension from the file name
-  if ( !fileName.toLower().endsWith( ".xml" ) )
+  if ( !fileName.endsWith( ".xml", Qt::CaseInsensitive ) )
   {
     fileName += ".xml";
   }
diff --git a/src/app/qgsnewspatialitelayerdialog.cpp b/src/app/qgsnewspatialitelayerdialog.cpp
index a4c555bb766c..2f1657e23137 100644
--- a/src/app/qgsnewspatialitelayerdialog.cpp
+++ b/src/app/qgsnewspatialitelayerdialog.cpp
@@ -117,7 +117,7 @@ void QgsNewSpatialiteLayerDialog::on_toolButtonNewDatabase_clicked()
   if ( fileName.isEmpty() )
     return;
 
-  if ( !fileName.toLower().endsWith( ".sqlite" ) && !fileName.toLower().endsWith( ".db" ) )
+  if ( !fileName.endsWith( ".sqlite", Qt::CaseInsensitive ) && !fileName.endsWith( ".db", Qt::CaseInsensitive ) )
   {
     fileName += ".sqlite";
   }
diff --git a/src/app/qgsoptions.cpp b/src/app/qgsoptions.cpp
index a6e4bb5f332c..558001801710 100644
--- a/src/app/qgsoptions.cpp
+++ b/src/app/qgsoptions.cpp
@@ -2001,7 +2001,7 @@ void QgsOptions::on_pbnExportScales_clicked()
   }
 
   // ensure the user never ommited the extension from the file name
-  if ( !fileName.toLower().endsWith( ".xml" ) )
+  if ( !fileName.endsWith( ".xml", Qt::CaseInsensitive ) )
   {
     fileName += ".xml";
   }
@@ -2160,7 +2160,7 @@ void QgsOptions::on_mButtonExportColors_clicked()
   }
 
   // ensure filename contains extension
-  if ( !fileName.toLower().endsWith( ".gpl" ) )
+  if ( !fileName.endsWith( ".gpl", Qt::CaseInsensitive ) )
   {
     fileName += ".gpl";
   }
diff --git a/src/app/qgsprojectproperties.cpp b/src/app/qgsprojectproperties.cpp
index ff261e21c767..cef458c45698 100644
--- a/src/app/qgsprojectproperties.cpp
+++ b/src/app/qgsprojectproperties.cpp
@@ -643,7 +643,7 @@ QgsProjectProperties::QgsProjectProperties( QgsMapCanvas* mapCanvas, QWidget *pa
   mTabRelations->layout()->addWidget( mRelationManagerDlg );
 
   QList<QgsVectorLayer*> vectorLayers;
-  Q_FOREACH ( QgsMapLayer* mapLayer, mapLayers.values() )
+  Q_FOREACH ( QgsMapLayer* mapLayer, mapLayers )
   {
     if ( QgsMapLayer::VectorLayer == mapLayer->type() )
     {
@@ -1482,7 +1482,7 @@ void QgsProjectProperties::on_pbnLaunchOWSChecker_clicked()
 
   QStringList duplicateNames, regExpMessages;
   QRegExp snRegExp = QgsApplication::shortNameRegExp();
-  Q_FOREACH ( QString name, owsNames )
+  Q_FOREACH ( const QString& name, owsNames )
   {
     if ( !snRegExp.exactMatch( name ) )
       regExpMessages << tr( "Use short name for \"%1\"" ).arg( name );
@@ -1583,7 +1583,7 @@ void QgsProjectProperties::on_pbnExportScales_clicked()
   }
 
   // ensure the user never ommited the extension from the file name
-  if ( !fileName.toLower().endsWith( ".xml" ) )
+  if ( !fileName.endsWith( ".xml", Qt::CaseInsensitive ) )
   {
     fileName += ".xml";
   }
@@ -2015,7 +2015,7 @@ void QgsProjectProperties::on_mButtonExportColors_clicked()
   }
 
   // ensure filename contains extension
-  if ( !fileName.toLower().endsWith( ".gpl" ) )
+  if ( !fileName.endsWith( ".gpl", Qt::CaseInsensitive ) )
   {
     fileName += ".gpl";
   }
diff --git a/src/gui/editorwidgets/qgsvaluemapconfigdlg.cpp b/src/gui/editorwidgets/qgsvaluemapconfigdlg.cpp
index 8fc5f95e5343..97377079721f 100644
--- a/src/gui/editorwidgets/qgsvaluemapconfigdlg.cpp
+++ b/src/gui/editorwidgets/qgsvaluemapconfigdlg.cpp
@@ -111,7 +111,7 @@ void QgsValueMapConfigDlg::removeSelectedButtonPushed()
       }
     }
   }
-  for ( i = 0; i < rowsToRemove.values().size(); i++ )
+  for ( i = 0; i < rowsToRemove.size(); i++ )
   {
     tableWidget->removeRow( rowsToRemove.values().at( i ) - removed );
     removed++;
diff --git a/src/gui/qgisgui.cpp b/src/gui/qgisgui.cpp
index a86910142fba..894a49891026 100644
--- a/src/gui/qgisgui.cpp
+++ b/src/gui/qgisgui.cpp
@@ -168,7 +168,7 @@ namespace QgisGui
 #endif
 
     // Add the file type suffix to the fileName if required
-    if ( !ext.isNull() && !outputFileName.toLower().endsWith( '.' + ext.toLower() ) )
+    if ( !ext.isNull() && !outputFileName.endsWith( '.' + ext.toLower(), Qt::CaseInsensitive ) )
     {
       outputFileName += '.' + ext;
     }
diff --git a/src/gui/qgscolordialog.cpp b/src/gui/qgscolordialog.cpp
index 9abf82e1dfd8..bf065e0d7d54 100644
--- a/src/gui/qgscolordialog.cpp
+++ b/src/gui/qgscolordialog.cpp
@@ -572,7 +572,7 @@ void QgsColorDialogV2::exportColors()
   }
 
   // ensure filename contains extension
-  if ( !fileName.toLower().endsWith( ".gpl" ) )
+  if ( !fileName.endsWith( ".gpl", Qt::CaseInsensitive ) )
   {
     fileName += ".gpl";
   }
diff --git a/src/gui/qgsmanageconnectionsdialog.cpp b/src/gui/qgsmanageconnectionsdialog.cpp
index f6bb97f74f62..22a338d51807 100644
--- a/src/gui/qgsmanageconnectionsdialog.cpp
+++ b/src/gui/qgsmanageconnectionsdialog.cpp
@@ -99,7 +99,7 @@ void QgsManageConnectionsDialog::doExportImport()
     }
 
     // ensure the user never ommited the extension from the file name
-    if ( !fileName.toLower().endsWith( ".xml" ) )
+    if ( !fileName.endsWith( ".xml", Qt::CaseInsensitive ) )
     {
       fileName += ".xml";
     }
diff --git a/src/gui/qgsprojectionselector.cpp b/src/gui/qgsprojectionselector.cpp
index 96bf5b00c57a..acfcfa849e4c 100644
--- a/src/gui/qgsprojectionselector.cpp
+++ b/src/gui/qgsprojectionselector.cpp
@@ -172,7 +172,7 @@ QString QgsProjectionSelector::ogcWmsCrsFilterAsSqlExpression( QSet<QString> * c
 
   // iterate through all incoming CRSs
 
-  Q_FOREACH ( const QString& auth_id, crsFilter->values() )
+  Q_FOREACH ( const QString& auth_id, *crsFilter )
   {
     QStringList parts = auth_id.split( ':' );
 
diff --git a/src/gui/qgsrasterlayersaveasdialog.cpp b/src/gui/qgsrasterlayersaveasdialog.cpp
index cfa43018b235..89bce90f45af 100644
--- a/src/gui/qgsrasterlayersaveasdialog.cpp
+++ b/src/gui/qgsrasterlayersaveasdialog.cpp
@@ -204,7 +204,7 @@ void QgsRasterLayerSaveAsDialog::on_mBrowseButton_clicked()
   if ( !fileName.isEmpty() )
   {
     // ensure the user never ommited the extension from the file name
-    if ( !fileName.toLower().endsWith( ".tif" ) && !fileName.toLower().endsWith( ".tiff" ) )
+    if ( !fileName.endsWith( ".tif", Qt::CaseInsensitive ) && !fileName.endsWith( ".tiff", Qt::CaseInsensitive ) )
     {
       fileName += ".tif";
     }
diff --git a/src/gui/symbology-ng/qgssmartgroupeditordialog.cpp b/src/gui/symbology-ng/qgssmartgroupeditordialog.cpp
index 384982e0f237..b6f7bb3b8a36 100644
--- a/src/gui/symbology-ng/qgssmartgroupeditordialog.cpp
+++ b/src/gui/symbology-ng/qgssmartgroupeditordialog.cpp
@@ -106,7 +106,7 @@ void QgsSmartGroupEditorDialog::addCondition()
   // enable the remove buttons when 2nd condition is added
   if ( mConditionMap.count() == 1 )
   {
-    Q_FOREACH ( QgsSmartGroupCondition *condition, mConditionMap.values() )
+    Q_FOREACH ( QgsSmartGroupCondition *condition, mConditionMap )
     {
       condition->hideRemoveButton( false );
     }
@@ -128,7 +128,7 @@ void QgsSmartGroupEditorDialog::removeCondition( int id )
   // hide the remove button of the last condition when 2nd last is removed
   if ( mConditionMap.count() == 2 )
   {
-    Q_FOREACH ( QgsSmartGroupCondition* condition, mConditionMap.values() )
+    Q_FOREACH ( QgsSmartGroupCondition* condition, mConditionMap )
     {
       condition->hideRemoveButton( true );
     }
@@ -142,7 +142,7 @@ QgsSmartConditionMap QgsSmartGroupEditorDialog::conditionMap()
 {
   QgsSmartConditionMap conditions;
 
-  Q_FOREACH ( QgsSmartGroupCondition* condition, mConditionMap.values() )
+  Q_FOREACH ( QgsSmartGroupCondition* condition, mConditionMap )
   {
     conditions.insert( condition->constraint(), condition->parameter() );
   }
diff --git a/src/gui/symbology-ng/qgsstylev2exportimportdialog.cpp b/src/gui/symbology-ng/qgsstylev2exportimportdialog.cpp
index 298ab250d217..692f1d8e886c 100644
--- a/src/gui/symbology-ng/qgsstylev2exportimportdialog.cpp
+++ b/src/gui/symbology-ng/qgsstylev2exportimportdialog.cpp
@@ -134,7 +134,7 @@ void QgsStyleV2ExportImportDialog::doExportImport()
     }
 
     // ensure the user never ommited the extension from the file name
-    if ( !fileName.toLower().endsWith( ".xml" ) )
+    if ( !fileName.endsWith( ".xml", Qt::CaseInsensitive ) )
     {
       fileName += ".xml";
     }
diff --git a/src/plugins/dxf2shp_converter/dxf2shpconvertergui.cpp b/src/plugins/dxf2shp_converter/dxf2shpconvertergui.cpp
index 637b2018636e..4c276e5e541d 100644
--- a/src/plugins/dxf2shp_converter/dxf2shpconvertergui.cpp
+++ b/src/plugins/dxf2shp_converter/dxf2shpconvertergui.cpp
@@ -163,7 +163,7 @@ void dxf2shpConverterGui::getOutputDir()
 
   if ( !s.isEmpty() )
   {
-    if ( !s.toLower().endsWith( ".shp" ) )
+    if ( !s.endsWith( ".shp", Qt::CaseInsensitive ) )
     {
       s += ".shp";
     }
diff --git a/src/plugins/gps_importer/qgsgpsplugin.cpp b/src/plugins/gps_importer/qgsgpsplugin.cpp
index cffb39ed8f7e..b367d4e20f1d 100644
--- a/src/plugins/gps_importer/qgsgpsplugin.cpp
+++ b/src/plugins/gps_importer/qgsgpsplugin.cpp
@@ -174,7 +174,7 @@ void QgsGPSPlugin::createGPX()
                                   tr( "GPS eXchange file" ) + " (*.gpx)" );
   if ( !fileName.isEmpty() )
   {
-    if ( !fileName.toLower().endsWith( ".gpx" ) )
+    if ( !fileName.endsWith( ".gpx", Qt::CaseInsensitive ) )
     {
       fileName += ".gpx";
     }
diff --git a/src/plugins/gps_importer/qgsgpsplugingui.cpp b/src/plugins/gps_importer/qgsgpsplugingui.cpp
index a4fe4d1c88ec..9e1d23ed6ac3 100644
--- a/src/plugins/gps_importer/qgsgpsplugingui.cpp
+++ b/src/plugins/gps_importer/qgsgpsplugingui.cpp
@@ -116,7 +116,7 @@ void QgsGPSPluginGui::on_buttonBox_accepted()
       int featureType = cmbDLFeatureType->currentIndex();
 
       QString fileName = leDLOutput->text();
-      if ( !fileName.toLower().endsWith( ".gpx" ) )
+      if ( !fileName.endsWith( ".gpx", Qt::CaseInsensitive ) )
       {
         fileName += ".gpx";
       }
@@ -166,7 +166,7 @@ void QgsGPSPluginGui::on_pbnDLOutput_clicked()
                                   tr( "GPS eXchange format" ) + " (*.gpx)" );
   if ( !myFileNameQString.isEmpty() )
   {
-    if ( !myFileNameQString.toLower().endsWith( ".gpx" ) )
+    if ( !myFileNameQString.endsWith( ".gpx", Qt::CaseInsensitive ) )
     {
       myFileNameQString += ".gpx";
     }
@@ -316,7 +316,7 @@ void QgsGPSPluginGui::on_pbnIMPOutput_clicked()
                                   tr( "GPS eXchange format" ) + " (*.gpx)" );
   if ( !myFileNameQString.isEmpty() )
   {
-    if ( !myFileNameQString.toLower().endsWith( ".gpx" ) )
+    if ( !myFileNameQString.endsWith( ".gpx", Qt::CaseInsensitive ) )
     {
       myFileNameQString += ".gpx";
     }
@@ -423,7 +423,7 @@ void QgsGPSPluginGui::on_pbnCONVOutput_clicked()
                                   tr( "GPS eXchange format" ) + " (*.gpx)" );
   if ( !myFileNameQString.isEmpty() )
   {
-    if ( !myFileNameQString.toLower().endsWith( ".gpx" ) )
+    if ( !myFileNameQString.endsWith( ".gpx", Qt::CaseInsensitive ) )
     {
       myFileNameQString += ".gpx";
     }
diff --git a/src/plugins/offline_editing/offline_editing_plugin_gui.cpp b/src/plugins/offline_editing/offline_editing_plugin_gui.cpp
index 5b84b986e1d4..7dd54af84c6b 100644
--- a/src/plugins/offline_editing/offline_editing_plugin_gui.cpp
+++ b/src/plugins/offline_editing/offline_editing_plugin_gui.cpp
@@ -117,7 +117,7 @@ void QgsOfflineEditingPluginGui::on_mBrowseButton_clicked()
 
   if ( !fileName.isEmpty() )
   {
-    if ( !fileName.toLower().endsWith( ".sqlite" ) )
+    if ( !fileName.endsWith( ".sqlite", Qt::CaseInsensitive ) )
     {
       fileName += ".sqlite";
     }
diff --git a/src/providers/virtual/qgsvirtuallayersourceselect.cpp b/src/providers/virtual/qgsvirtuallayersourceselect.cpp
index a901f169cd4a..1bcb3d6ce7b3 100644
--- a/src/providers/virtual/qgsvirtuallayersourceselect.cpp
+++ b/src/providers/virtual/qgsvirtuallayersourceselect.cpp
@@ -87,7 +87,7 @@ QgsVirtualLayerSourceSelect::QgsVirtualLayerSourceSelect( QWidget* parent, Qt::W
   }
 
   // configure auto completion with table and column names
-  Q_FOREACH ( QgsMapLayer* l, QgsMapLayerRegistry::instance()->mapLayers().values() )
+  Q_FOREACH ( QgsMapLayer* l, QgsMapLayerRegistry::instance()->mapLayers() )
   {
     if ( l->type() == QgsMapLayer::VectorLayer )
     {
diff --git a/tests/src/gui/testprojectionissues.cpp b/tests/src/gui/testprojectionissues.cpp
index 6d4d3c199422..2f76121c444a 100644
--- a/tests/src/gui/testprojectionissues.cpp
+++ b/tests/src/gui/testprojectionissues.cpp
@@ -68,7 +68,7 @@ void TestProjectionIssues::initTestCase()
 
   // Add all layers in registry to the canvas
   QList<QgsMapCanvasLayer> canvasLayers;
-  Q_FOREACH ( QgsMapLayer* layer, QgsMapLayerRegistry::instance()->mapLayers().values() )
+  Q_FOREACH ( QgsMapLayer* layer, QgsMapLayerRegistry::instance()->mapLayers() )
   {
     canvasLayers.append( QgsMapCanvasLayer( layer ) );
   }