diff --git a/geom/geom/inc/TGeoExtension.h b/geom/geom/inc/TGeoExtension.h
index 8b9cd4fcddc813a7f0abdf27db3ac1eac7fd3f24..e68d572d5827a183b07a4cda1ab3b059045d5fbb 100644
--- a/geom/geom/inc/TGeoExtension.h
+++ b/geom/geom/inc/TGeoExtension.h
@@ -71,7 +71,7 @@ public:
 private:
    // Copy constructor and assignment not allowed
    TGeoRCExtension(const TGeoRCExtension &); // Not implemented
-   TGeoRCExtension &operator =(const TGeoRCExtension &) {return *this;}
+   TGeoRCExtension &operator =(const TGeoRCExtension &); // Not implemented
    mutable Int_t        fRC;           // Reference counter
    TObject             *fUserObject;   // Attached user object