diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index ab25f16e87d..9d7247130f2 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -467,10 +467,18 @@ impl ShorthandId {
         }
     }
 
-    // Overflow does not behave like a normal shorthand. When overflow-x and overflow-y are not of equal
-    // values, they no longer use the shared property name "overflow".
-    pub fn overflow_longhands_to_css<'a, W, I>(&self, declarations: I, dest: &mut W) -> fmt::Result
-        where W: fmt::Write, I: Iterator<Item=&'a PropertyDeclaration> {
+    /// Overflow does not behave like a normal shorthand. When overflow-x and
+    /// overflow-y are not of equal values, they no longer use the shared
+    /// property name "overflow".
+    ///
+    /// We use this function as a special-case for that.
+    pub fn overflow_longhands_to_css<'a, W, I>(&self,
+                                               declarations: I,
+                                               dest: &mut W)
+                                               -> fmt::Result
+        where W: fmt::Write,
+              I: Iterator<Item=&'a PropertyDeclaration>,
+    {
         match *self {
             ShorthandId::Overflow => {
                 match shorthands::overflow::LonghandsToSerialize::from_iter(declarations) {