diff --git a/components/style/values/specified/basic_shape.rs b/components/style/values/specified/basic_shape.rs
index e4c0544af9d..52343621b5e 100644
--- a/components/style/values/specified/basic_shape.rs
+++ b/components/style/values/specified/basic_shape.rs
@@ -97,7 +97,6 @@ impl Parse for FloatAreaShape {
 impl<ReferenceBox, ImageOrUrl> ShapeSource<BasicShape, ReferenceBox, ImageOrUrl>
 where
     ReferenceBox: Parse,
-    ImageOrUrl: Parse,
 {
     /// The internal parser for ShapeSource.
     fn parse_common<'i, 't>(