diff --git a/src/imports/qtcanvas3d/context3d.cpp b/src/imports/qtcanvas3d/context3d.cpp
index b3a99b4cec810b393a4d84177ceb6a5881a3f506..0b15a556f838524b6b847d204166299b47c5ddfa 100644
--- a/src/imports/qtcanvas3d/context3d.cpp
+++ b/src/imports/qtcanvas3d/context3d.cpp
@@ -6120,7 +6120,7 @@ QVariantList CanvasContext::getSupportedExtensions()
 /*!
  * \internal
  */
-bool CanvasContext::isOfType(const QJSValue &value, const QString &classname) const
+bool CanvasContext::isOfType(const QJSValue &value, const char *classname) const
 {
     if (!value.isQObject()) {
         return false;
@@ -6131,7 +6131,7 @@ bool CanvasContext::isOfType(const QJSValue &value, const QString &classname) co
     if (!obj)
         return false;
 
-    if (!obj->inherits(classname.toLocal8Bit().constData())) {
+    if (!obj->inherits(classname)) {
         return false;
     }
 
diff --git a/src/imports/qtcanvas3d/context3d_p.h b/src/imports/qtcanvas3d/context3d_p.h
index 37b021eb5f941ae2a9b12317ab677eab459dbe58..d34ca39552012b0cad306982b764af819d0a69e9 100644
--- a/src/imports/qtcanvas3d/context3d_p.h
+++ b/src/imports/qtcanvas3d/context3d_p.h
@@ -1225,7 +1225,7 @@ private:
     uchar *unpackPixels(uchar *srcData, bool useSrcDataAsDst,
                         int bytesPerPixel, int width, int height);
 
-    bool isOfType(const QJSValue &value, const QString &classname) const;
+    bool isOfType(const QJSValue &value, const char *classname) const;
 
     bool isValidTextureBound(glEnums target, const QString &funcName);
     bool checkParent(QObject *jsObj, const char *function);