bogus warning

since...

commit 9c79945c
Date:   Sun Jun 12 20:11:20 2016 +0200

    convert DBG_ASSERT in vcl

Change-Id: I67b2f0d21965a70980c4f0c522a0431107216a27

vcl/source/gdi/bitmapex.cxx

@@ -380,7 +380,7 @@ bool BitmapEx::Scale( const double& rScaleX, const double& rScaleY, BmpScaleFlag
 
         aBitmapSize = aBitmap.GetSizePixel();
 
-        SAL_WARN_IF( !aMask || aBitmap.GetSizePixel() == aMask.GetSizePixel(), "vcl",
+        SAL_WARN_IF( !!aMask && aBitmap.GetSizePixel() != aMask.GetSizePixel(), "vcl",
                     "BitmapEx::Scale(): size mismatch for bitmap and alpha mask." );
     }