--- a/servo/components/style/properties/longhand/svg.mako.rs
+++ b/servo/components/style/properties/longhand/svg.mako.rs
@@ -23,30 +23,30 @@
     "stop-color", "RGBAColor",
     "RGBA::new(0, 0, 0, 255)",
     products="gecko",
     animation_value_type="none",
     spec="https://www.w3.org/TR/SVGTiny12/painting.html#StopColorProperty")}
 
 ${helpers.predefined_type("stop-opacity", "Opacity", "1.0",
                           products="gecko",
-                          animation_value_type="none",
+                          animation_value_type="ComputedValue",
                           spec="https://www.w3.org/TR/SVGTiny12/painting.html#propdef-stop-opacity")}
 
 // Section 15 - Filter Effects
 
 ${helpers.predefined_type(
     "flood-color", "RGBAColor",
     "RGBA::new(0, 0, 0, 255)",
     products="gecko",
     animation_value_type="none",
     spec="https://www.w3.org/TR/SVG/filters.html#FloodColorProperty")}
 
 ${helpers.predefined_type("flood-opacity", "Opacity",
-                          "1.0", products="gecko", animation_value_type="none",
+                          "1.0", products="gecko", animation_value_type="ComputedValue",
                           spec="https://www.w3.org/TR/SVG/filters.html#FloodOpacityProperty")}
 
 ${helpers.predefined_type(
     "lighting-color", "RGBAColor",
     "RGBA::new(255, 255, 255, 255)",
     products="gecko",
     animation_value_type="none",
     spec="https://www.w3.org/TR/SVG/filters.html#LightingColorProperty")}