diff --git a/components/style/values/computed/mod.rs b/components/style/values/computed/mod.rs
index af6d416a20d..94cc1706c4a 100644
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@@ -312,26 +312,6 @@ impl<T> ToComputedValue for Box<[T]>
     }
 }
 
-/// A marker trait to represent that the specified value is also the computed
-/// value.
-pub trait ComputedValueAsSpecified {}
-
-impl<T> ToComputedValue for T
-    where T: ComputedValueAsSpecified + Clone,
-{
-    type ComputedValue = T;
-
-    #[inline]
-    fn to_computed_value(&self, _context: &Context) -> T {
-        self.clone()
-    }
-
-    #[inline]
-    fn from_computed_value(computed: &T) -> Self {
-        computed.clone()
-    }
-}
-
 trivial_to_computed_value!(());
 trivial_to_computed_value!(bool);
 trivial_to_computed_value!(f32);
diff --git a/components/style/values/generics/image.rs b/components/style/values/generics/image.rs
index 874511330d4..a0b2cb1b281 100644
--- a/components/style/values/generics/image.rs
+++ b/components/style/values/generics/image.rs
@@ -34,11 +34,7 @@ pub enum Image<Gradient, MozImageRect, ImageUrl> {
     PaintWorklet(PaintWorklet),
 }
 
-// Can't just use derive(ToComputedValue) on Image, because when trying to do
-// "impl<T> ToComputedValue for Box<T>" the Rust compiler complains that
-// "impl<T> ToComputedValue for T where T: ComputedValueAsSpecified + Clone"
-// aleady implements ToComputedValue for std::boxed::Box<_> and hence we have
-// conflicting implementations.
+// FIXME(nox): Implement TCV for Box<T> and derive this.
 impl<Gradient: ToComputedValue,
      MozImageRect: ToComputedValue,
      ImageUrl: ToComputedValue> ToComputedValue for Image<Gradient, MozImageRect, ImageUrl> {