diff --git a/source b/source
index 4d3eee86ebe..68eea5ec21f 100644
--- a/source
+++ b/source
@@ -59921,7 +59921,7 @@ interface CanvasFillStrokeStyles {
attribute (DOMString or CanvasGradient or CanvasPattern) fillStyle; // (default black)
CanvasGradient createLinearGradient(double x0, double y0, double x1, double y1);
CanvasGradient createRadialGradient(double x0, double y0, double r0, double x1, double y1, double r1);
- CanvasPattern createPattern(CanvasImageSource image, [TreatNullAs=EmptyString] DOMString repetition);
+ CanvasPattern? createPattern(CanvasImageSource image, [TreatNullAs=EmptyString] DOMString repetition);