diff --git a/components/style/cbindgen.toml b/components/style/cbindgen.toml
index c0eeee9b968..46162e43db5 100644
--- a/components/style/cbindgen.toml
+++ b/components/style/cbindgen.toml
@@ -23,5 +23,11 @@ derive_helper_methods = true
 
 [export]
 prefix = "Style"
-include = ["StyleDisplay", "StyleAppearance", "StyleDisplayMode", "StylePathCommand"]
+include = [
+  "StyleAppearance",
+  "StyleDisplay",
+  "StyleDisplayMode",
+  "StyleFillRule",
+  "StylePathCommand"
+]
 item_types = ["enums", "structs", "typedefs"]
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 596dc29fb19..76d61838708 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -4986,10 +4986,10 @@ fn static_assert() {
     pub fn set_${ident}(&mut self, v: longhands::${ident}::computed_value::T) {
         use gecko_bindings::bindings::{Gecko_NewBasicShape, Gecko_DestroyShapeSource};
         use gecko_bindings::structs::{StyleBasicShape, StyleBasicShapeType, StyleShapeSourceType};
-        use gecko_bindings::structs::{StyleFillRule, StyleGeometryBox, StyleShapeSource};
+        use gecko_bindings::structs::{StyleGeometryBox, StyleShapeSource};
         use gecko::conversions::basic_shape::set_corners_from_radius;
         use gecko::values::GeckoStyleCoordConvertible;
-        use values::generics::basic_shape::{BasicShape, FillRule, ShapeSource};
+        use values::generics::basic_shape::{BasicShape, ShapeSource};
 
         let ref mut ${ident} = self.gecko.${gecko_ffi_name};
 
@@ -5083,11 +5083,8 @@ fn static_assert() {
                             coord.0.to_gecko_style_coord(&mut shape.mCoordinates[2 * i]);
                             coord.1.to_gecko_style_coord(&mut shape.mCoordinates[2 * i + 1]);
                         }
-                        shape.mFillRule = if poly.fill == FillRule::Evenodd {
-                            StyleFillRule::Evenodd
-                        } else {
-                            StyleFillRule::Nonzero
-                        };
+                        // unsafe: cbindgen ensures the representation is the same.
+                        shape.mFillRule = unsafe { transmute(poly.fill) };
                     }
                 }
 
diff --git a/components/style/values/generics/basic_shape.rs b/components/style/values/generics/basic_shape.rs
index 274673b9c61..ee7455e777d 100644
--- a/components/style/values/generics/basic_shape.rs
+++ b/components/style/values/generics/basic_shape.rs
@@ -138,6 +138,7 @@ pub struct PolygonCoord<LengthOrPercentage>(pub LengthOrPercentage, pub LengthOr
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq,
          SpecifiedValueInfo, ToComputedValue, ToCss)]
+#[repr(u8)]
 pub enum FillRule {
     Nonzero,
     Evenodd,