diff --git a/components/style/stylesheets/mod.rs b/components/style/stylesheets/mod.rs
index 6c30de2c3a2..91d1bbc30c4 100644
--- a/components/style/stylesheets/mod.rs
+++ b/components/style/stylesheets/mod.rs
@@ -178,25 +178,25 @@ impl UrlExtraData {
     }
 }
 
-macro_rules! define_debug_struct {
-    ($struct_name:ident, $gecko_class:ident, $debug_fn:ident) => {
-        struct $struct_name(*mut structs::$gecko_class);
-        impl fmt::Debug for $struct_name {
-            fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-                use nsstring::nsCString;
-                let mut spec = nsCString::new();
-                unsafe {
-                    bindings::$debug_fn(self.0, &mut spec);
-                }
-                spec.fmt(formatter)
-            }
-        }
-    }
-}
-
 #[cfg(feature = "gecko")]
 impl fmt::Debug for UrlExtraData {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        macro_rules! define_debug_struct {
+            ($struct_name:ident, $gecko_class:ident, $debug_fn:ident) => {
+                struct $struct_name(*mut structs::$gecko_class);
+                impl fmt::Debug for $struct_name {
+                    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                        use nsstring::nsCString;
+                        let mut spec = nsCString::new();
+                        unsafe {
+                            bindings::$debug_fn(self.0, &mut spec);
+                        }
+                        spec.fmt(formatter)
+                    }
+                }
+            }
+        }
+
         define_debug_struct!(DebugURI, nsIURI, Gecko_nsIURI_Debug);
         define_debug_struct!(DebugReferrerInfo, nsIReferrerInfo, Gecko_nsIReferrerInfo_Debug);