--- a/servo/components/style/matching.rs
+++ b/servo/components/style/matching.rs
@@ -571,39 +571,41 @@ trait PrivateMatchMethods: TElement {
             pseudo_style.as_mut().map_or_else(|| primary_style.values.take(), |p| p.1.values.take());
 
         // Compute the new values.
         let mut new_values = self.cascade_internal(context, primary_style,
                                                    &mut pseudo_style, &booleans);
 
         // Handle animations.
         if booleans.animate {
-            if let Some(ref mut old) = old_values {
-                self.update_animations_for_cascade(shared_context, old,
-                                                   possibly_expired_animations);
-            }
+            if cfg!(feature = "servo") {
+                if let Some(ref mut old) = old_values {
+                    self.update_animations_for_cascade(shared_context, old,
+                                                       possibly_expired_animations);
+                }
 
-            let new_animations_sender = &context.thread_local.new_animations_sender;
-            let this_opaque = self.as_node().opaque();
-            // Trigger any present animations if necessary.
-            animation::maybe_start_animations(&shared_context,
-                                              new_animations_sender,
-                                              this_opaque, &new_values);
+                let new_animations_sender = &context.thread_local.new_animations_sender;
+                let this_opaque = self.as_node().opaque();
+                // Trigger any present animations if necessary.
+                animation::maybe_start_animations(&shared_context,
+                                                  new_animations_sender,
+                                                  this_opaque, &new_values);
 
-            // Trigger transitions if necessary. This will reset `new_values` back
-            // to its old value if it did trigger a transition.
-            if let Some(ref values) = old_values {
-                animation::start_transitions_if_applicable(
-                    new_animations_sender,
-                    this_opaque,
-                    self.as_node().to_unsafe(),
-                    &**values,
-                    &mut new_values,
-                    &shared_context.timer,
-                    &possibly_expired_animations);
+                // Trigger transitions if necessary. This will reset `new_values` back
+                // to its old value if it did trigger a transition.
+                if let Some(ref values) = old_values {
+                    animation::start_transitions_if_applicable(
+                        new_animations_sender,
+                        this_opaque,
+                        self.as_node().to_unsafe(),
+                        &**values,
+                        &mut new_values,
+                        &shared_context.timer,
+                        &possibly_expired_animations);
+                }
             }
         }
 
         // Accumulate restyle damage.
         if let Some(old) = old_values {
             self.accumulate_damage(restyle.unwrap(), &old, &new_values, pseudo);
         }