diff --git a/python/core/auto_generated/symbology/qgsfillsymbollayer.sip.in b/python/core/auto_generated/symbology/qgsfillsymbollayer.sip.in
index 881ae2e5ea5..2f77d100756 100644
--- a/python/core/auto_generated/symbology/qgsfillsymbollayer.sip.in
+++ b/python/core/auto_generated/symbology/qgsfillsymbollayer.sip.in
@@ -45,7 +45,7 @@ Caller takes ownership of the returned symbol layer.
     virtual void stopRender( QgsSymbolRenderContext &context );
 
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
 
     virtual QgsStringMap properties() const;
@@ -214,7 +214,7 @@ Caller takes ownership of the returned symbol layer.
     virtual void stopRender( QgsSymbolRenderContext &context );
 
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
 
     virtual QgsStringMap properties() const;
@@ -374,7 +374,7 @@ Caller takes ownership of the returned symbol layer.
     virtual void stopRender( QgsSymbolRenderContext &context );
 
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
 
     virtual QgsStringMap properties() const;
@@ -686,7 +686,7 @@ Base class for polygon renderers generating texture images*
   public:
 
     QgsImageFillSymbolLayer();
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
 
     virtual QgsSymbol *subSymbol();
@@ -806,7 +806,7 @@ Used internally when reading/writing symbols.
 
     virtual QString layerType() const;
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
     virtual void startRender( QgsSymbolRenderContext &context );
 
@@ -1952,7 +1952,7 @@ Caller takes ownership of the returned symbol layer.
 
     virtual void stopRender( QgsSymbolRenderContext &context );
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
     virtual QgsStringMap properties() const;
 
@@ -2139,7 +2139,7 @@ Caller takes ownership of the returned symbol layer.
     virtual void stopRender( QgsSymbolRenderContext &context );
 
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
 
     virtual QgsStringMap properties() const;
diff --git a/python/core/auto_generated/symbology/qgslinesymbollayer.sip.in b/python/core/auto_generated/symbology/qgslinesymbollayer.sip.in
index 7de6431c415..9a92e86f4cb 100644
--- a/python/core/auto_generated/symbology/qgslinesymbollayer.sip.in
+++ b/python/core/auto_generated/symbology/qgslinesymbollayer.sip.in
@@ -52,7 +52,7 @@ Creates a new QgsSimpleLineSymbolLayer from an SLD XML DOM ``element``.
 
     virtual void renderPolyline( const QPolygonF &points, QgsSymbolRenderContext &context );
 
-    virtual void renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
     virtual QgsStringMap properties() const;
 
@@ -506,7 +506,7 @@ calculating individual symbol angles.
 
     virtual void renderPolyline( const QPolygonF &points, QgsSymbolRenderContext &context ) ${SIP_FINAL};
 
-    virtual void renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) ${SIP_FINAL};
+    virtual void renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) ${SIP_FINAL};
 
     virtual QgsUnitTypes::RenderUnit outputUnit() const ${SIP_FINAL};
 
diff --git a/python/core/auto_generated/symbology/qgssymbol.sip.in b/python/core/auto_generated/symbology/qgssymbol.sip.in
index 9d52954af1c..bed4207ccdc 100644
--- a/python/core/auto_generated/symbology/qgssymbol.sip.in
+++ b/python/core/auto_generated/symbology/qgssymbol.sip.in
@@ -548,7 +548,7 @@ If ``correctRingOrientation`` is ``True`` then the ring will be oriented to matc
 clockwise for exterior rings and counter-clockwise for interior rings.
 %End
 
-    static void _getPolygon( QPolygonF &pts, QList<QPolygonF> &holes, QgsRenderContext &context, const QgsPolygon &polygon, bool clipToExtent = true, bool correctRingOrientation = false );
+    static void _getPolygon( QPolygonF &pts, QVector<QPolygonF> &holes, QgsRenderContext &context, const QgsPolygon &polygon, bool clipToExtent = true, bool correctRingOrientation = false );
 %Docstring
 Creates a polygon in screen coordinates from a QgsPolygonXYin map coordinates
 
@@ -1206,7 +1206,7 @@ Ownership of the ``layers`` are transferred to the symbol.
 %End
     void setAngle( double angle );
 
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, const QgsFeature *f, QgsRenderContext &context, int layer = -1, bool selected = false );
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, const QgsFeature *f, QgsRenderContext &context, int layer = -1, bool selected = false );
 %Docstring
 Renders the symbol using the given render ``context``.
 
diff --git a/python/core/auto_generated/symbology/qgssymbollayer.sip.in b/python/core/auto_generated/symbology/qgssymbollayer.sip.in
index 7cb68f80d9e..6233069b41f 100644
--- a/python/core/auto_generated/symbology/qgssymbollayer.sip.in
+++ b/python/core/auto_generated/symbology/qgssymbollayer.sip.in
@@ -979,7 +979,7 @@ Renders the line symbol layer along the line joining ``points``, using the given
 .. seealso:: :py:func:`renderPolygonStroke`
 %End
 
-    virtual void renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 %Docstring
 Renders the line symbol layer along the outline of polygon, using the given render ``context``.
 
@@ -1167,9 +1167,11 @@ class QgsFillSymbolLayer : QgsSymbolLayer
 
 
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) = 0;
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) = 0;
 %Docstring
-QgsFillSymbolLayer cannot be copied
+Renders the fill symbol layer for the polygon whose outer ring is defined by ``points``, using the given render ``context``.
+
+The ``rings`` argument optionally specifies a list of polygon rings to render as holes.
 %End
 
     virtual void drawPreviewIcon( QgsSymbolRenderContext &context, QSize size );
@@ -1180,7 +1182,7 @@ QgsFillSymbolLayer cannot be copied
 
   protected:
     QgsFillSymbolLayer( bool locked = false );
-    void _renderPolygon( QPainter *p, const QPolygonF &points, const QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    void _renderPolygon( QPainter *p, const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 %Docstring
 Default method to render polygon
 %End
diff --git a/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in b/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in
index 260aa6fa9f1..a252bffa3c2 100644
--- a/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in
+++ b/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in
@@ -713,7 +713,7 @@ Determines an SVG symbol's name from its ``path``.
 Calculate the centroid point of a QPolygonF
 %End
 
-    static QPointF polygonPointOnSurface( const QPolygonF &points, QList<QPolygonF> *rings = 0 );
+    static QPointF polygonPointOnSurface( const QPolygonF &points, const QVector<QPolygonF> *rings = 0 );
 %Docstring
 Calculate a point on the surface of a QPolygonF
 %End
diff --git a/src/core/annotations/qgsannotation.cpp b/src/core/annotations/qgsannotation.cpp
index 3d2002ecf4b..ca10aea16cd 100644
--- a/src/core/annotations/qgsannotation.cpp
+++ b/src/core/annotations/qgsannotation.cpp
@@ -358,7 +358,7 @@ void QgsAnnotation::drawFrame( QgsRenderContext &context ) const
 
   QPolygonF poly;
   poly.reserve( 9 + ( mHasFixedMapPosition ? 3 : 0 ) );
-  QList<QPolygonF> rings; //empty list
+  QVector<QPolygonF> rings; //empty list
   for ( int i = 0; i < 4; ++i )
   {
     QLineF currentSegment = segment( i, &context );
diff --git a/src/core/layout/qgslayoutitemmapoverview.cpp b/src/core/layout/qgslayoutitemmapoverview.cpp
index 8e5283ec653..e2753d3cc1a 100644
--- a/src/core/layout/qgslayoutitemmapoverview.cpp
+++ b/src/core/layout/qgslayoutitemmapoverview.cpp
@@ -127,7 +127,7 @@ void QgsLayoutItemMapOverview::draw( QPainter *painter )
   QPolygonF intersectPolygon;
   intersectPolygon = mapTransform.map( intersectExtent );
 
-  QList<QPolygonF> rings; //empty list
+  QVector<QPolygonF> rings; //empty list
   if ( !mInverted )
   {
     //Render the intersecting map extent
diff --git a/src/core/layout/qgslayoutitempage.cpp b/src/core/layout/qgslayoutitempage.cpp
index 4582e446dfb..5b7d62c3d17 100644
--- a/src/core/layout/qgslayoutitempage.cpp
+++ b/src/core/layout/qgslayoutitempage.cpp
@@ -280,7 +280,7 @@ void QgsLayoutItemPage::draw( QgsLayoutItemRenderContext &context )
     // round up
     QPolygonF pagePolygon = QPolygonF( QRectF( maxBleedPixels, maxBleedPixels,
                                        std::ceil( rect().width() * scale ) - 2 * maxBleedPixels, std::ceil( rect().height() * scale ) - 2 * maxBleedPixels ) );
-    QList<QPolygonF> rings; //empty list
+    QVector<QPolygonF> rings; //empty list
 
     symbol->renderPolygon( pagePolygon, &rings, nullptr, context.renderContext() );
     symbol->stopRender( context.renderContext() );
diff --git a/src/core/layout/qgslayoutitempolygon.cpp b/src/core/layout/qgslayoutitempolygon.cpp
index 4657b0e2a1b..879d0fdc03d 100644
--- a/src/core/layout/qgslayoutitempolygon.cpp
+++ b/src/core/layout/qgslayoutitempolygon.cpp
@@ -117,7 +117,7 @@ void QgsLayoutItemPolygon::_draw( QgsLayoutItemRenderContext &context, const QSt
   double scale = context.renderContext().convertToPainterUnits( 1, QgsUnitTypes::RenderMillimeters );
   QTransform t = QTransform::fromScale( scale, scale );
 
-  QList<QPolygonF> rings; //empty
+  QVector<QPolygonF> rings; //empty
   QPainterPath polygonPath;
   polygonPath.addPolygon( mPolygon );
 
diff --git a/src/core/layout/qgslayoutitemshape.cpp b/src/core/layout/qgslayoutitemshape.cpp
index 9c70f1caf52..97f303ce9a4 100644
--- a/src/core/layout/qgslayoutitemshape.cpp
+++ b/src/core/layout/qgslayoutitemshape.cpp
@@ -217,7 +217,7 @@ void QgsLayoutItemShape::draw( QgsLayoutItemRenderContext &context )
     }
   }
 
-  QList<QPolygonF> rings; //empty list
+  QVector<QPolygonF> rings; //empty list
 
   symbol()->startRender( context.renderContext() );
   symbol()->renderPolygon( shapePolygon, &rings, nullptr, context.renderContext() );
diff --git a/src/core/symbology/qgsfillsymbollayer.cpp b/src/core/symbology/qgsfillsymbollayer.cpp
index 7784b6eea50..ee5d5b71979 100644
--- a/src/core/symbology/qgsfillsymbollayer.cpp
+++ b/src/core/symbology/qgsfillsymbollayer.cpp
@@ -263,7 +263,7 @@ void QgsSimpleFillSymbolLayer::stopRender( QgsSymbolRenderContext &context )
   Q_UNUSED( context )
 }
 
-void QgsSimpleFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsSimpleFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   QPainter *p = context.renderContext().painter();
   if ( !p )
@@ -842,7 +842,7 @@ void QgsGradientFillSymbolLayer::stopRender( QgsSymbolRenderContext &context )
   Q_UNUSED( context )
 }
 
-void QgsGradientFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsGradientFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   QPainter *p = context.renderContext().painter();
   if ( !p )
@@ -1129,7 +1129,7 @@ void QgsShapeburstFillSymbolLayer::stopRender( QgsSymbolRenderContext &context )
   Q_UNUSED( context )
 }
 
-void QgsShapeburstFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsShapeburstFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   QPainter *p = context.renderContext().painter();
   if ( !p )
@@ -1560,7 +1560,7 @@ QgsImageFillSymbolLayer::QgsImageFillSymbolLayer()
   setSubSymbol( new QgsLineSymbol() );
 }
 
-void QgsImageFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsImageFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   QPainter *p = context.renderContext().painter();
   if ( !p )
@@ -1606,8 +1606,7 @@ void QgsImageFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPol
     mStroke->renderPolyline( points, context.feature(), context.renderContext(), -1, SELECT_FILL_BORDER && context.selected() );
     if ( rings )
     {
-      QList<QPolygonF>::const_iterator ringIt = rings->constBegin();
-      for ( ; ringIt != rings->constEnd(); ++ringIt )
+      for ( auto ringIt = rings->constBegin(); ringIt != rings->constEnd(); ++ringIt )
       {
         mStroke->renderPolyline( *ringIt, context.feature(), context.renderContext(), -1, SELECT_FILL_BORDER && context.selected() );
       }
@@ -3507,7 +3506,7 @@ void QgsCentroidFillSymbolLayer::stopRender( QgsSymbolRenderContext &context )
   mMarker->stopRender( context.renderContext() );
 }
 
-void QgsCentroidFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsCentroidFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   if ( !mPointOnAllParts )
   {
@@ -3758,7 +3757,7 @@ QString QgsRasterFillSymbolLayer::layerType() const
   return QStringLiteral( "RasterFill" );
 }
 
-void QgsRasterFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsRasterFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   QPainter *p = context.renderContext().painter();
   if ( !p )
@@ -4009,7 +4008,7 @@ void QgsRandomMarkerFillSymbolLayer::stopRender( QgsSymbolRenderContext &context
   mMarker->stopRender( context.renderContext() );
 }
 
-void QgsRandomMarkerFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsRandomMarkerFillSymbolLayer::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   Part part;
   part.exterior = points;
diff --git a/src/core/symbology/qgsfillsymbollayer.h b/src/core/symbology/qgsfillsymbollayer.h
index c90f6d72ee8..96cecb6e112 100644
--- a/src/core/symbology/qgsfillsymbollayer.h
+++ b/src/core/symbology/qgsfillsymbollayer.h
@@ -65,7 +65,7 @@ class CORE_EXPORT QgsSimpleFillSymbolLayer : public QgsFillSymbolLayer
 
     void stopRender( QgsSymbolRenderContext &context ) override;
 
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
 
     QgsStringMap properties() const override;
 
@@ -229,7 +229,7 @@ class CORE_EXPORT QgsGradientFillSymbolLayer : public QgsFillSymbolLayer
 
     void stopRender( QgsSymbolRenderContext &context ) override;
 
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
 
     QgsStringMap properties() const override;
 
@@ -391,7 +391,7 @@ class CORE_EXPORT QgsShapeburstFillSymbolLayer : public QgsFillSymbolLayer
 
     void stopRender( QgsSymbolRenderContext &context ) override;
 
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
 
     QgsStringMap properties() const override;
 
@@ -648,7 +648,7 @@ class CORE_EXPORT QgsImageFillSymbolLayer: public QgsFillSymbolLayer
   public:
 
     QgsImageFillSymbolLayer();
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
 
     QgsSymbol *subSymbol() override { return mStroke.get(); }
     bool setSubSymbol( QgsSymbol *symbol SIP_TRANSFER ) override;
@@ -754,7 +754,7 @@ class CORE_EXPORT QgsRasterFillSymbolLayer: public QgsImageFillSymbolLayer
 
     // implemented from base classes
     QString layerType() const override;
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
     void startRender( QgsSymbolRenderContext &context ) override;
     void stopRender( QgsSymbolRenderContext &context ) override;
     QgsStringMap properties() const override;
@@ -1759,7 +1759,7 @@ class CORE_EXPORT QgsRandomMarkerFillSymbolLayer : public QgsFillSymbolLayer
     QString layerType() const override;
     void startRender( QgsSymbolRenderContext &context ) override;
     void stopRender( QgsSymbolRenderContext &context ) override;
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
     QgsStringMap properties() const override;
     QgsRandomMarkerFillSymbolLayer *clone() const override SIP_FACTORY;
 
@@ -1895,7 +1895,7 @@ class CORE_EXPORT QgsRandomMarkerFillSymbolLayer : public QgsFillSymbolLayer
     struct Part
     {
       QPolygonF exterior;
-      QList<QPolygonF> rings;
+      QVector<QPolygonF> rings;
     };
 
     QVector< Part > mCurrentParts;
@@ -1942,7 +1942,7 @@ class CORE_EXPORT QgsCentroidFillSymbolLayer : public QgsFillSymbolLayer
 
     void stopRender( QgsSymbolRenderContext &context ) override;
 
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
 
     QgsStringMap properties() const override;
 
diff --git a/src/core/symbology/qgslinesymbollayer.cpp b/src/core/symbology/qgslinesymbollayer.cpp
index 3485da28ac9..99428045d4d 100644
--- a/src/core/symbology/qgslinesymbollayer.cpp
+++ b/src/core/symbology/qgslinesymbollayer.cpp
@@ -238,7 +238,7 @@ void QgsSimpleLineSymbolLayer::stopRender( QgsSymbolRenderContext &context )
   Q_UNUSED( context )
 }
 
-void QgsSimpleLineSymbolLayer::renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsSimpleLineSymbolLayer::renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   QPainter *p = context.renderContext().painter();
   if ( !p )
@@ -263,8 +263,7 @@ void QgsSimpleLineSymbolLayer::renderPolygonStroke( const QPolygonF &points, QLi
         if ( rings )
         {
           //add polygon rings
-          QList<QPolygonF>::const_iterator it = rings->constBegin();
-          for ( ; it != rings->constEnd(); ++it )
+          for ( auto it = rings->constBegin(); it != rings->constEnd(); ++it )
           {
             QPolygonF ring = *it;
             clipPath.addPolygon( ring );
@@ -867,7 +866,7 @@ void QgsTemplatedLineSymbolLayerBase::renderPolyline( const QPolygonF &points, Q
   context.renderContext().painter()->restore();
 }
 
-void QgsTemplatedLineSymbolLayerBase::renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsTemplatedLineSymbolLayerBase::renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   const QgsCurvePolygon *curvePolygon = dynamic_cast<const QgsCurvePolygon *>( context.renderContext().geometry() );
 
diff --git a/src/core/symbology/qgslinesymbollayer.h b/src/core/symbology/qgslinesymbollayer.h
index 7afb0b80af0..431f879c7f2 100644
--- a/src/core/symbology/qgslinesymbollayer.h
+++ b/src/core/symbology/qgslinesymbollayer.h
@@ -68,7 +68,7 @@ class CORE_EXPORT QgsSimpleLineSymbolLayer : public QgsLineSymbolLayer
     void stopRender( QgsSymbolRenderContext &context ) override;
     void renderPolyline( const QPolygonF &points, QgsSymbolRenderContext &context ) override;
     //overridden so that clip path can be set when using draw inside polygon option
-    void renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
+    void renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) override;
     QgsStringMap properties() const override;
     QgsSimpleLineSymbolLayer *clone() const override SIP_FACTORY;
     void toSld( QDomDocument &doc, QDomElement &element, const QgsStringMap &props ) const override;
@@ -467,7 +467,7 @@ class CORE_EXPORT QgsTemplatedLineSymbolLayerBase : public QgsLineSymbolLayer
     const QgsMapUnitScale &averageAngleMapUnitScale() const { return mAverageAngleLengthMapUnitScale; }
 
     void renderPolyline( const QPolygonF &points, QgsSymbolRenderContext &context ) FINAL;
-    void renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) FINAL;
+    void renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) FINAL;
     QgsUnitTypes::RenderUnit outputUnit() const FINAL;
     void setMapUnitScale( const QgsMapUnitScale &scale ) FINAL;
     QgsMapUnitScale mapUnitScale() const FINAL;
diff --git a/src/core/symbology/qgssymbol.cpp b/src/core/symbology/qgssymbol.cpp
index 81d13baa94d..a8121bdd63e 100644
--- a/src/core/symbology/qgssymbol.cpp
+++ b/src/core/symbology/qgssymbol.cpp
@@ -214,15 +214,18 @@ QPolygonF QgsSymbol::_getPolygonRing( QgsRenderContext &context, const QgsCurve
   return poly;
 }
 
-void QgsSymbol::_getPolygon( QPolygonF &pts, QList<QPolygonF> &holes, QgsRenderContext &context, const QgsPolygon &polygon, const bool clipToExtent, const bool correctRingOrientation )
+void QgsSymbol::_getPolygon( QPolygonF &pts, QVector<QPolygonF> &holes, QgsRenderContext &context, const QgsPolygon &polygon, const bool clipToExtent, const bool correctRingOrientation )
 {
   holes.clear();
 
   pts = _getPolygonRing( context, *polygon.exteriorRing(), clipToExtent, true, correctRingOrientation );
-  for ( int idx = 0; idx < polygon.numInteriorRings(); idx++ )
+  const int ringCount = polygon.numInteriorRings();
+  holes.reserve( ringCount );
+  for ( int idx = 0; idx < ringCount; idx++ )
   {
     const QPolygonF hole = _getPolygonRing( context, *( polygon.interiorRing( idx ) ), clipToExtent, false, correctRingOrientation );
-    if ( !hole.isEmpty() ) holes.append( hole );
+    if ( !hole.isEmpty() )
+      holes.append( hole );
   }
 }
 
@@ -560,7 +563,7 @@ void QgsSymbol::drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext
 
         for ( const QList< QPolygonF > &poly : polys )
         {
-          QList< QPolygonF > rings;
+          QVector< QPolygonF > rings;
           for ( int i = 1; i < poly.size(); ++i )
             rings << poly.at( i );
           lsl->renderPolygonStroke( poly.value( 0 ), &rings, symbolContext );
@@ -878,8 +881,13 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
 
   QgsGeometry renderedBoundsGeom;
 
-  startFeatureRender( feature, context, layer );
-
+  // Step 1 - collect the set of painter coordinate geometries to render.
+  // We do this upfront, because we only want to ever do this once, regardless how many symbol layers we need to render.
+  QVector< QPointF > pointsToRender;
+  QVector< QPolygonF > linesToRender;
+  QVector< QPolygonF > polygonsToRender;
+  QVector< QVector< QPolygonF > > polygonRingsToRender;
+  std::map<double, QList<unsigned int> > mapAreaToPartNum;
   switch ( QgsWkbTypes::flatType( segmentizedGeometry.constGet()->wkbType() ) )
   {
     case QgsWkbTypes::Point:
@@ -892,7 +900,8 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
 
       const QgsPoint *point = static_cast< const QgsPoint * >( segmentizedGeometry.constGet() );
       const QPointF pt = _getPoint( context, *point );
-      static_cast<QgsMarkerSymbol *>( this )->renderPoint( pt, &feature, context, layer, selected );
+
+      pointsToRender << pt;
 
       if ( context.hasRenderedFeatureHandlers() || context.testFlag( QgsRenderContext::DrawSymbolBounds ) )
       {
@@ -914,8 +923,9 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       {
         markers << pt;
       }
+      break;
     }
-    break;
+
     case QgsWkbTypes::LineString:
     {
       if ( mType != QgsSymbol::Line )
@@ -925,7 +935,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       }
       const QgsCurve &curve = dynamic_cast<const QgsCurve &>( *segmentizedGeometry.constGet() );
       const QPolygonF pts = _getLineString( context, curve, !tileMapRendering && clipFeaturesToExtent() );
-      static_cast<QgsLineSymbol *>( this )->renderPolyline( pts, &feature, context, layer, selected );
+      linesToRender << pts;
 
       if ( context.hasRenderedFeatureHandlers() )
         renderedBoundsGeom = QgsGeometry::fromQPolygonF( pts );
@@ -934,13 +944,14 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       {
         markers = pts;
       }
+      break;
     }
-    break;
+
     case QgsWkbTypes::Polygon:
     case QgsWkbTypes::Triangle:
     {
       QPolygonF pts;
-      QList<QPolygonF> holes;
+      QVector<QPolygonF> holes;
       if ( mType != QgsSymbol::Fill )
       {
         QgsDebugMsg( QStringLiteral( "polygon can be drawn only with fill symbol!" ) );
@@ -953,7 +964,8 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         break;
       }
       _getPolygon( pts, holes, context, polygon, !tileMapRendering && clipFeaturesToExtent(), mForceRHR );
-      static_cast<QgsFillSymbol *>( this )->renderPolygon( pts, ( !holes.isEmpty() ? &holes : nullptr ), &feature, context, layer, selected );
+      polygonsToRender << pts;
+      polygonRingsToRender << holes;
 
       if ( context.hasRenderedFeatureHandlers() )
         renderedBoundsGeom = QgsGeometry::fromQPolygonF( pts ); // TODO - consider holes?
@@ -968,8 +980,8 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
           markers << hole;
         }
       }
+      break;
     }
-    break;
 
     case QgsWkbTypes::MultiPoint:
     {
@@ -980,24 +992,13 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       }
 
       const QgsMultiPoint &mp = static_cast< const QgsMultiPoint & >( *segmentizedGeometry.constGet() );
-
-      if ( drawVertexMarker && !usingSegmentizedGeometry )
-      {
-        markers.reserve( mp.numGeometries() );
-      }
+      markers.reserve( mp.numGeometries() );
 
       for ( int i = 0; i < mp.numGeometries(); ++i )
       {
-        if ( context.renderingStopped() )
-          break;
-
-        mSymbolRenderContext->setGeometryPartNum( i + 1 );
-        if ( needsExpressionContext )
-          mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QgsExpressionContext::EXPR_GEOMETRY_PART_NUM, i + 1, true ) );
-
         const QgsPoint &point = static_cast< const QgsPoint & >( *mp.geometryN( i ) );
         const QPointF pt = _getPoint( context, point );
-        static_cast<QgsMarkerSymbol *>( this )->renderPoint( pt, &feature, context, layer, selected );
+        pointsToRender << pt;
 
         if ( context.hasRenderedFeatureHandlers() )
         {
@@ -1010,8 +1011,8 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
           markers.append( pt );
         }
       }
+      break;
     }
-    break;
 
     case QgsWkbTypes::MultiCurve:
     case QgsWkbTypes::MultiLineString:
@@ -1030,14 +1031,9 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         if ( context.renderingStopped() )
           break;
 
-        mSymbolRenderContext->setGeometryPartNum( i + 1 );
-        if ( needsExpressionContext )
-          mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QgsExpressionContext::EXPR_GEOMETRY_PART_NUM, i + 1, true ) );
-
-        context.setGeometry( geomCollection.geometryN( i ) );
         const QgsCurve &curve = dynamic_cast<const QgsCurve &>( *geomCollection.geometryN( i ) );
         const QPolygonF pts = _getLineString( context, curve, !tileMapRendering && clipFeaturesToExtent() );
-        static_cast<QgsLineSymbol *>( this )->renderPolyline( pts, &feature, context, layer, selected );
+        linesToRender << pts;
 
         if ( context.hasRenderedFeatureHandlers() )
         {
@@ -1049,8 +1045,8 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
           markers << pts;
         }
       }
+      break;
     }
-    break;
 
     case QgsWkbTypes::MultiSurface:
     case QgsWkbTypes::MultiPolygon:
@@ -1062,14 +1058,13 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       }
 
       QPolygonF pts;
-      QList<QPolygonF> holes;
+      QVector<QPolygonF> holes;
 
       const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
       const unsigned int num = geomCollection.numGeometries();
 
       // Sort components by approximate area (probably a bit faster than using
       // area() )
-      std::map<double, QList<unsigned int> > mapAreaToPartNum;
       for ( unsigned int i = 0; i < num; ++i )
       {
         const QgsPolygon &polygon = dynamic_cast<const QgsPolygon &>( *geomCollection.geometryN( i ) );
@@ -1086,21 +1081,14 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         const QList<unsigned int> &listPartIndex = iter->second;
         for ( int idx = 0; idx < listPartIndex.size(); ++idx )
         {
-          if ( context.renderingStopped() )
-            break;
-
           const unsigned i = listPartIndex[idx];
-          mSymbolRenderContext->setGeometryPartNum( i + 1 );
-          if ( needsExpressionContext )
-            mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QgsExpressionContext::EXPR_GEOMETRY_PART_NUM, i + 1, true ) );
-
-          context.setGeometry( geomCollection.geometryN( i ) );
           const QgsPolygon &polygon = dynamic_cast<const QgsPolygon &>( *geomCollection.geometryN( i ) );
           if ( !polygon.exteriorRing() )
             break;
 
           _getPolygon( pts, holes, context, polygon, !tileMapRendering && clipFeaturesToExtent(), mForceRHR );
-          static_cast<QgsFillSymbol *>( this )->renderPolygon( pts, ( !holes.isEmpty() ? &holes : nullptr ), &feature, context, layer, selected );
+          polygonsToRender << pts;
+          polygonRingsToRender << holes;
 
           if ( context.hasRenderedFeatureHandlers() )
           {
@@ -1121,6 +1109,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       }
       break;
     }
+
     case QgsWkbTypes::GeometryCollection:
     {
       const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
@@ -1132,6 +1121,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
 
       FALLTHROUGH
     }
+
     default:
       QgsDebugMsg( QStringLiteral( "feature %1: unsupported wkb type %2/%3 for rendering" )
                    .arg( feature.id() )
@@ -1139,7 +1129,175 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
                    .arg( geom.wkbType(), 0, 16 ) );
   }
 
-  stopFeatureRender( feature, context, layer );
+  // step 2 - determine which layers to render
+  std::vector< int > layers;
+  if ( layer == -1 )
+  {
+    layers.reserve( mLayers.count() );
+    for ( int i = 0; i < mLayers.count(); ++i )
+      layers.emplace_back( i );
+  }
+  else
+  {
+    layers.emplace_back( layer );
+  }
+
+  // step 3 - render these geometries using the desired symbol layers.
+
+  if ( needsExpressionContext )
+    mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "symbol_layer_count" ), mLayers.count(), true ) );
+
+  for ( const int symbolLayerIndex : layers )
+  {
+    QgsSymbolLayer *symbolLayer = mLayers.value( symbolLayerIndex );
+    if ( !symbolLayer || !symbolLayer->enabled() )
+      continue;
+
+    if ( needsExpressionContext )
+      mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "symbol_layer_index" ), symbolLayerIndex + 1, true ) );
+
+    symbolLayer->startFeatureRender( feature, context );
+    switch ( QgsWkbTypes::flatType( segmentizedGeometry.constGet()->wkbType() ) )
+    {
+      case QgsWkbTypes::Point:
+      {
+        if ( pointsToRender.empty() )
+        {
+          break;
+        }
+
+        static_cast<QgsMarkerSymbol *>( this )->renderPoint( pointsToRender.at( 0 ), &feature, context, symbolLayerIndex, selected );
+        break;
+      }
+
+      case QgsWkbTypes::LineString:
+      {
+        if ( linesToRender.empty() )
+        {
+          break;
+        }
+
+        static_cast<QgsLineSymbol *>( this )->renderPolyline( linesToRender.at( 0 ), &feature, context, symbolLayerIndex, selected );
+        break;
+      }
+
+      case QgsWkbTypes::Polygon:
+      case QgsWkbTypes::Triangle:
+      {
+        if ( polygonsToRender.empty() )
+        {
+          break;
+        }
+
+        static_cast<QgsFillSymbol *>( this )->renderPolygon( polygonsToRender.at( 0 ), ( !polygonRingsToRender.at( 0 ).isEmpty() ? &polygonRingsToRender.at( 0 ) : nullptr ), &feature, context, symbolLayerIndex, selected );
+        break;
+      }
+
+      case QgsWkbTypes::MultiPoint:
+      {
+        if ( pointsToRender.empty() )
+        {
+          break;
+        }
+
+        const QgsMultiPoint &mp = static_cast< const QgsMultiPoint & >( *segmentizedGeometry.constGet() );
+        for ( int i = 0; i < mp.numGeometries(); ++i )
+        {
+          if ( context.renderingStopped() )
+            break;
+
+          mSymbolRenderContext->setGeometryPartNum( i + 1 );
+          if ( needsExpressionContext )
+            mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QgsExpressionContext::EXPR_GEOMETRY_PART_NUM, i + 1, true ) );
+
+          static_cast<QgsMarkerSymbol *>( this )->renderPoint( pointsToRender.at( i ), &feature, context, symbolLayerIndex, selected );
+        }
+        break;
+      }
+
+      case QgsWkbTypes::MultiCurve:
+      case QgsWkbTypes::MultiLineString:
+      {
+        if ( linesToRender.empty() )
+        {
+          break;
+        }
+
+        const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
+
+        const unsigned int num = geomCollection.numGeometries();
+        for ( unsigned int i = 0; i < num; ++i )
+        {
+          if ( context.renderingStopped() )
+            break;
+
+          mSymbolRenderContext->setGeometryPartNum( i + 1 );
+          if ( needsExpressionContext )
+            mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QgsExpressionContext::EXPR_GEOMETRY_PART_NUM, i + 1, true ) );
+
+          context.setGeometry( geomCollection.geometryN( i ) );
+          static_cast<QgsLineSymbol *>( this )->renderPolyline( linesToRender.at( 0 ), &feature, context, symbolLayerIndex, selected );
+        }
+        break;
+      }
+
+      case QgsWkbTypes::MultiSurface:
+      case QgsWkbTypes::MultiPolygon:
+      {
+        if ( polygonsToRender.empty() )
+        {
+          break;
+        }
+
+        // Draw starting with larger parts down to smaller parts, so that in
+        // case of a part being incorrectly inside another part, it is drawn
+        // on top of it (#15419)
+        std::map<double, QList<unsigned int> >::const_reverse_iterator iter = mapAreaToPartNum.rbegin();
+        int polyIndex = 0;
+        for ( ; iter != mapAreaToPartNum.rend(); ++iter )
+        {
+          const QList<unsigned int> &listPartIndex = iter->second;
+          for ( int idx = 0; idx < listPartIndex.size(); ++idx )
+          {
+            if ( context.renderingStopped() )
+              break;
+
+            const unsigned i = listPartIndex[idx];
+            mSymbolRenderContext->setGeometryPartNum( i + 1 );
+            if ( needsExpressionContext )
+              mSymbolRenderContext->expressionContextScope()->addVariable( QgsExpressionContextScope::StaticVariable( QgsExpressionContext::EXPR_GEOMETRY_PART_NUM, i + 1, true ) );
+
+            const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
+            context.setGeometry( geomCollection.geometryN( i ) );
+
+            static_cast<QgsFillSymbol *>( this )->renderPolygon( polygonsToRender.at( polyIndex ), ( !polygonRingsToRender.at( polyIndex ).isEmpty() ? &polygonRingsToRender.at( polyIndex ) : nullptr ), &feature, context, symbolLayerIndex, selected );
+            polyIndex++;
+          }
+        }
+        break;
+      }
+
+      case QgsWkbTypes::GeometryCollection:
+      {
+        const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
+        if ( geomCollection.numGeometries() == 0 )
+        {
+          // skip noise from empty geometry collections from simplification
+          break;
+        }
+
+        FALLTHROUGH
+      }
+
+      default:
+        QgsDebugMsg( QStringLiteral( "feature %1: unsupported wkb type %2/%3 for rendering" )
+                     .arg( feature.id() )
+                     .arg( QgsWkbTypes::displayString( geom.constGet()->wkbType() ) )
+                     .arg( geom.wkbType(), 0, 16 ) );
+    }
+
+    symbolLayer->stopFeatureRender( feature, context );
+  }
 
   if ( context.hasRenderedFeatureHandlers() )
   {
@@ -2055,7 +2213,7 @@ QgsFillSymbol::QgsFillSymbol( const QgsSymbolLayerList &layers )
     mLayers.append( new QgsSimpleFillSymbolLayer() );
 }
 
-void QgsFillSymbol::renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, const QgsFeature *f, QgsRenderContext &context, int layerIdx, bool selected )
+void QgsFillSymbol::renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, const QgsFeature *f, QgsRenderContext &context, int layerIdx, bool selected )
 {
   QgsSymbolRenderContext symbolContext( context, QgsUnitTypes::RenderUnknownUnit, mOpacity, selected, mRenderHints, f );
   symbolContext.setOriginalGeometryType( QgsWkbTypes::PolygonGeometry );
@@ -2091,7 +2249,7 @@ void QgsFillSymbol::renderPolygon( const QPolygonF &points, QList<QPolygonF> *ri
   }
 }
 
-void QgsFillSymbol::renderPolygonUsingLayer( QgsSymbolLayer *layer, const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsFillSymbol::renderPolygonUsingLayer( QgsSymbolLayer *layer, const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   if ( layer->dataDefinedProperties().hasActiveProperties() && !layer->dataDefinedProperties().valueAsBool( QgsSymbolLayer::PropertyLayerEnabled, context.renderContext().expressionContext(), true ) )
     return;
@@ -2102,7 +2260,7 @@ void QgsFillSymbol::renderPolygonUsingLayer( QgsSymbolLayer *layer, const QPolyg
   if ( effect && effect->enabled() )
   {
     QRectF bounds = polygonBounds( points, rings );
-    QList<QPolygonF> *translatedRings = translateRings( rings, -bounds.left(), -bounds.top() );
+    QVector<QPolygonF> *translatedRings = translateRings( rings, -bounds.left(), -bounds.top() );
 
     QgsEffectPainter p( context.renderContext() );
     p->translate( bounds.topLeft() );
@@ -2130,13 +2288,12 @@ void QgsFillSymbol::renderPolygonUsingLayer( QgsSymbolLayer *layer, const QPolyg
   }
 }
 
-QRectF QgsFillSymbol::polygonBounds( const QPolygonF &points, const QList<QPolygonF> *rings ) const
+QRectF QgsFillSymbol::polygonBounds( const QPolygonF &points, const QVector<QPolygonF> *rings ) const
 {
   QRectF bounds = points.boundingRect();
   if ( rings )
   {
-    QList<QPolygonF>::const_iterator it = rings->constBegin();
-    for ( ; it != rings->constEnd(); ++it )
+    for ( auto it = rings->constBegin(); it != rings->constEnd(); ++it )
     {
       bounds = bounds.united( ( *it ).boundingRect() );
     }
@@ -2144,14 +2301,14 @@ QRectF QgsFillSymbol::polygonBounds( const QPolygonF &points, const QList<QPolyg
   return bounds;
 }
 
-QList<QPolygonF> *QgsFillSymbol::translateRings( const QList<QPolygonF> *rings, double dx, double dy ) const
+QVector<QPolygonF> *QgsFillSymbol::translateRings( const QVector<QPolygonF> *rings, double dx, double dy ) const
 {
   if ( !rings )
     return nullptr;
 
-  QList<QPolygonF> *translatedRings = new QList<QPolygonF>;
-  QList<QPolygonF>::const_iterator it = rings->constBegin();
-  for ( ; it != rings->constEnd(); ++it )
+  QVector<QPolygonF> *translatedRings = new QVector<QPolygonF>;
+  translatedRings->reserve( rings->size() );
+  for ( auto it = rings->constBegin(); it != rings->constEnd(); ++it )
   {
     translatedRings->append( ( *it ).translated( dx, dy ) );
   }
diff --git a/src/core/symbology/qgssymbol.h b/src/core/symbology/qgssymbol.h
index 50bf6046c8a..b7fab05994e 100644
--- a/src/core/symbology/qgssymbol.h
+++ b/src/core/symbology/qgssymbol.h
@@ -589,7 +589,7 @@ class CORE_EXPORT QgsSymbol
      * clockwise for exterior rings and counter-clockwise for interior rings.
      *
      */
-    static void _getPolygon( QPolygonF &pts, QList<QPolygonF> &holes, QgsRenderContext &context, const QgsPolygon &polygon, bool clipToExtent = true, bool correctRingOrientation = false );
+    static void _getPolygon( QPolygonF &pts, QVector<QPolygonF> &holes, QgsRenderContext &context, const QgsPolygon &polygon, bool clipToExtent = true, bool correctRingOrientation = false );
 
     /**
      * Retrieve a cloned list of all layers that make up this symbol.
@@ -1242,17 +1242,17 @@ class CORE_EXPORT QgsFillSymbol : public QgsSymbol
      * If \a selected is true then the symbol will be drawn using the "selected feature"
      * style and colors instead of the symbol's normal style.
      */
-    void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, const QgsFeature *f, QgsRenderContext &context, int layer = -1, bool selected = false );
+    void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, const QgsFeature *f, QgsRenderContext &context, int layer = -1, bool selected = false );
 
     QgsFillSymbol *clone() const override SIP_FACTORY;
 
   private:
 
-    void renderPolygonUsingLayer( QgsSymbolLayer *layer, const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    void renderPolygonUsingLayer( QgsSymbolLayer *layer, const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
     //! Calculates the bounds of a polygon including rings
-    QRectF polygonBounds( const QPolygonF &points, const QList<QPolygonF> *rings ) const;
+    QRectF polygonBounds( const QPolygonF &points, const QVector<QPolygonF> *rings ) const;
     //! Translates the rings in a polygon by a set distance
-    QList<QPolygonF> *translateRings( const QList<QPolygonF> *rings, double dx, double dy ) const;
+    QVector<QPolygonF> *translateRings( const QVector<QPolygonF> *rings, double dx, double dy ) const;
 };
 
 #endif
diff --git a/src/core/symbology/qgssymbollayer.cpp b/src/core/symbology/qgssymbollayer.cpp
index 3aafec3e75f..03211f339c0 100644
--- a/src/core/symbology/qgssymbollayer.cpp
+++ b/src/core/symbology/qgssymbollayer.cpp
@@ -657,7 +657,7 @@ void QgsLineSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSize
   stopRender( context );
 }
 
-void QgsLineSymbolLayer::renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsLineSymbolLayer::renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   switch ( mRingFilter )
   {
@@ -712,7 +712,7 @@ void QgsFillSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSize
 
   for ( const QList< QPolygonF > &poly : polys )
   {
-    QList< QPolygonF > rings;
+    QVector< QPolygonF > rings;
     for ( int i = 1; i < poly.size(); ++i )
       rings << poly.at( i );
     renderPolygon( poly.value( 0 ), &rings, context );
@@ -723,7 +723,7 @@ void QgsFillSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSize
   stopRender( context );
 }
 
-void QgsFillSymbolLayer::_renderPolygon( QPainter *p, const QPolygonF &points, const QList<QPolygonF> *rings, QgsSymbolRenderContext &context )
+void QgsFillSymbolLayer::_renderPolygon( QPainter *p, const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context )
 {
   if ( !p )
   {
@@ -757,8 +757,7 @@ void QgsFillSymbolLayer::_renderPolygon( QPainter *p, const QPolygonF &points, c
 
     if ( rings )
     {
-      QList<QPolygonF>::const_iterator it = rings->constBegin();
-      for ( ; it != rings->constEnd(); ++it )
+      for ( auto it = rings->constBegin(); it != rings->constEnd(); ++it )
       {
         QPolygonF ring = *it;
         path.addPolygon( ring );
diff --git a/src/core/symbology/qgssymbollayer.h b/src/core/symbology/qgssymbollayer.h
index 64ebe2b2642..cf140e4382d 100644
--- a/src/core/symbology/qgssymbollayer.h
+++ b/src/core/symbology/qgssymbollayer.h
@@ -929,7 +929,7 @@ class CORE_EXPORT QgsLineSymbolLayer : public QgsSymbolLayer
      *
      * \see renderPolyline()
      */
-    virtual void renderPolygonStroke( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    virtual void renderPolygonStroke( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
     /**
      * Sets the \a width of the line symbol layer.
@@ -1098,7 +1098,12 @@ class CORE_EXPORT QgsFillSymbolLayer : public QgsSymbolLayer
     //! QgsFillSymbolLayer cannot be copied
     QgsFillSymbolLayer &operator=( const QgsFillSymbolLayer &other ) = delete;
 
-    virtual void renderPolygon( const QPolygonF &points, QList<QPolygonF> *rings, QgsSymbolRenderContext &context ) = 0;
+    /**
+     * Renders the fill symbol layer for the polygon whose outer ring is defined by \a points, using the given render \a context.
+     *
+     * The \a rings argument optionally specifies a list of polygon rings to render as holes.
+     */
+    virtual void renderPolygon( const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context ) = 0;
 
     void drawPreviewIcon( QgsSymbolRenderContext &context, QSize size ) override;
 
@@ -1108,7 +1113,7 @@ class CORE_EXPORT QgsFillSymbolLayer : public QgsSymbolLayer
   protected:
     QgsFillSymbolLayer( bool locked = false );
     //! Default method to render polygon
-    void _renderPolygon( QPainter *p, const QPolygonF &points, const QList<QPolygonF> *rings, QgsSymbolRenderContext &context );
+    void _renderPolygon( QPainter *p, const QPolygonF &points, const QVector<QPolygonF> *rings, QgsSymbolRenderContext &context );
 
     double mAngle = 0.0;
 
diff --git a/src/core/symbology/qgssymbollayerutils.cpp b/src/core/symbology/qgssymbollayerutils.cpp
index 94956f99a4b..59d29c0d999 100644
--- a/src/core/symbology/qgssymbollayerutils.cpp
+++ b/src/core/symbology/qgssymbollayerutils.cpp
@@ -4008,7 +4008,7 @@ QPointF QgsSymbolLayerUtils::polygonCentroid( const QPolygonF &points )
   return QPointF( cx, cy );
 }
 
-QPointF QgsSymbolLayerUtils::polygonPointOnSurface( const QPolygonF &points, QList<QPolygonF> *rings )
+QPointF QgsSymbolLayerUtils::polygonPointOnSurface( const QPolygonF &points, const QVector<QPolygonF> *rings )
 {
   QPointF centroid = QgsSymbolLayerUtils::polygonCentroid( points );
 
@@ -4022,8 +4022,7 @@ QPointF QgsSymbolLayerUtils::polygonPointOnSurface( const QPolygonF &points, QLi
     {
       if ( rings )
       {
-        QList<QPolygonF>::const_iterator ringIt = rings->constBegin();
-        for ( ; ringIt != rings->constEnd(); ++ringIt )
+        for ( auto ringIt = rings->constBegin(); ringIt != rings->constEnd(); ++ringIt )
         {
           pointCount = ( *ringIt ).count();
           QgsPolylineXY polyline( pointCount );
diff --git a/src/core/symbology/qgssymbollayerutils.h b/src/core/symbology/qgssymbollayerutils.h
index 322f80dc12c..1513616749c 100644
--- a/src/core/symbology/qgssymbollayerutils.h
+++ b/src/core/symbology/qgssymbollayerutils.h
@@ -643,7 +643,7 @@ class CORE_EXPORT QgsSymbolLayerUtils
     static QPointF polygonCentroid( const QPolygonF &points );
 
     //! Calculate a point on the surface of a QPolygonF
-    static QPointF polygonPointOnSurface( const QPolygonF &points, QList<QPolygonF> *rings = nullptr );
+    static QPointF polygonPointOnSurface( const QPolygonF &points, const QVector<QPolygonF> *rings = nullptr );
 
     //! Calculate whether a point is within of a QPolygonF
     static bool pointInPolygon( const QPolygonF &points, QPointF point );