diff --git a/python/core/geometry/qgsabstractgeometry.sip b/python/core/geometry/qgsabstractgeometry.sip
index 022b6e3dd9d..aaec9451374 100644
--- a/python/core/geometry/qgsabstractgeometry.sip
+++ b/python/core/geometry/qgsabstractgeometry.sip
@@ -26,31 +26,31 @@ class QgsAbstractGeometry
 %End
 
 %ConvertToSubClassCode
-    if ( dynamic_cast<QgsPoint *>( sipCpp ) != NULL )
+    if ( qgsgeometry_cast<QgsPoint *>( sipCpp ) != nullptr )
       sipType = sipType_QgsPoint;
-    else if ( qgsgeometry_cast<QgsLineString *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsLineString *>( sipCpp ) != nullptr )
       sipType = sipType_QgsLineString;
-    else if ( qgsgeometry_cast<QgsCircularString *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsCircularString *>( sipCpp ) != nullptr )
       sipType = sipType_QgsCircularString;
-    else if ( qgsgeometry_cast<QgsCompoundCurve *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsCompoundCurve *>( sipCpp ) != nullptr )
       sipType = sipType_QgsCompoundCurve;
-    else if ( qgsgeometry_cast<QgsTriangle *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsTriangle *>( sipCpp ) != nullptr )
       sipType = sipType_QgsTriangle;
-    else if ( qgsgeometry_cast<QgsPolygonV2 *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsPolygonV2 *>( sipCpp ) != nullptr )
       sipType = sipType_QgsPolygonV2;
-    else if ( qgsgeometry_cast<QgsCurvePolygon *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsCurvePolygon *>( sipCpp ) != nullptr )
       sipType = sipType_QgsCurvePolygon;
-    else if ( qgsgeometry_cast<QgsMultiPointV2 *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiPointV2 *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiPointV2;
-    else if ( qgsgeometry_cast<QgsMultiLineString *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiLineString *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiLineString;
-    else if ( qgsgeometry_cast<QgsMultiPolygonV2 *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiPolygonV2 *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiPolygonV2;
-    else if ( qgsgeometry_cast<QgsMultiSurface *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiSurface *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiSurface;
-    else if ( qgsgeometry_cast<QgsMultiCurve *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiCurve *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiCurve;
-    else if ( qgsgeometry_cast<QgsGeometryCollection *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsGeometryCollection *>( sipCpp ) != nullptr )
       sipType = sipType_QgsGeometryCollection;
     else
       sipType = 0;
diff --git a/src/core/geometry/qgsabstractgeometry.h b/src/core/geometry/qgsabstractgeometry.h
index 31027738164..3d5e35ad566 100644
--- a/src/core/geometry/qgsabstractgeometry.h
+++ b/src/core/geometry/qgsabstractgeometry.h
@@ -53,31 +53,31 @@ class CORE_EXPORT QgsAbstractGeometry
 
 #ifdef SIP_RUN
     SIP_CONVERT_TO_SUBCLASS_CODE
-    if ( qgsgeometry_cast<QgsPoint *>( sipCpp ) != NULL )
+    if ( qgsgeometry_cast<QgsPoint *>( sipCpp ) != nullptr )
       sipType = sipType_QgsPoint;
-    else if ( qgsgeometry_cast<QgsLineString *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsLineString *>( sipCpp ) != nullptr )
       sipType = sipType_QgsLineString;
-    else if ( qgsgeometry_cast<QgsCircularString *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsCircularString *>( sipCpp ) != nullptr )
       sipType = sipType_QgsCircularString;
-    else if ( qgsgeometry_cast<QgsCompoundCurve *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsCompoundCurve *>( sipCpp ) != nullptr )
       sipType = sipType_QgsCompoundCurve;
-    else if ( qgsgeometry_cast<QgsTriangle *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsTriangle *>( sipCpp ) != nullptr )
       sipType = sipType_QgsTriangle;
-    else if ( qgsgeometry_cast<QgsPolygonV2 *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsPolygonV2 *>( sipCpp ) != nullptr )
       sipType = sipType_QgsPolygonV2;
-    else if ( qgsgeometry_cast<QgsCurvePolygon *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsCurvePolygon *>( sipCpp ) != nullptr )
       sipType = sipType_QgsCurvePolygon;
-    else if ( qgsgeometry_cast<QgsMultiPointV2 *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiPointV2 *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiPointV2;
-    else if ( qgsgeometry_cast<QgsMultiLineString *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiLineString *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiLineString;
-    else if ( qgsgeometry_cast<QgsMultiPolygonV2 *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiPolygonV2 *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiPolygonV2;
-    else if ( qgsgeometry_cast<QgsMultiSurface *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiSurface *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiSurface;
-    else if ( qgsgeometry_cast<QgsMultiCurve *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsMultiCurve *>( sipCpp ) != nullptr )
       sipType = sipType_QgsMultiCurve;
-    else if ( qgsgeometry_cast<QgsGeometryCollection *>( sipCpp ) != NULL )
+    else if ( qgsgeometry_cast<QgsGeometryCollection *>( sipCpp ) != nullptr )
       sipType = sipType_QgsGeometryCollection;
     else
       sipType = 0;