diff --git a/components/style/font_face.rs b/components/style/font_face.rs
index 4b3f6934f90..0d4bc4f8a09 100644
--- a/components/style/font_face.rs
+++ b/components/style/font_face.rs
@@ -21,7 +21,7 @@ use values::specified::url::SpecifiedUrl;
 
 /// A source for a font-face rule.
 #[derive(Clone, Debug, PartialEq, Eq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 pub enum Source {
     /// A `url()` source.
     Url(UrlSource),
@@ -54,7 +54,7 @@ impl OneOrMoreCommaSeparated for Source {}
 ///
 /// https://drafts.csswg.org/css-fonts/#src-desc
 #[derive(Clone, Debug, PartialEq, Eq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf, Deserialize, Serialize))]
+#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 pub struct UrlSource {
     /// The specified url.
     pub url: SpecifiedUrl,
@@ -184,7 +184,6 @@ macro_rules! font_face_descriptors {
         ///
         /// https://drafts.csswg.org/css-fonts/#font-face-rule
         #[derive(Debug, PartialEq, Eq)]
-        #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
         pub struct FontFaceRule {
             $(
                 #[$m_doc]
diff --git a/components/style/keyframes.rs b/components/style/keyframes.rs
index 40d8ef60b09..048d9904043 100644
--- a/components/style/keyframes.rs
+++ b/components/style/keyframes.rs
@@ -70,8 +70,7 @@ impl KeyframePercentage {
 
 /// A keyframes selector is a list of percentages or from/to symbols, which are
 /// converted at parse time to percentages.
-#[derive(Debug, Clone, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug, PartialEq)]
 pub struct KeyframeSelector(Vec<KeyframePercentage>);
 impl KeyframeSelector {
     /// Return the list of percentages this selector contains.
@@ -93,8 +92,7 @@ impl KeyframeSelector {
 }
 
 /// A keyframe.
-#[derive(Debug, Clone)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(Debug)]
 pub struct Keyframe {
     /// The selector this keyframe was specified from.
     pub selector: KeyframeSelector,
@@ -103,7 +101,6 @@ pub struct Keyframe {
     ///
     /// Note that `!important` rules in keyframes don't apply, but we keep this
     /// `Arc` just for convenience.
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "Arc")]
     pub block: Arc<RwLock<PropertyDeclarationBlock>>,
 }
 
@@ -148,7 +145,7 @@ impl Keyframe {
 /// declarations to apply.
 ///
 /// TODO: Find a better name for this?
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum KeyframesStepValue {
     /// A step formed by a declaration block specified by the CSS.
@@ -163,7 +160,7 @@ pub enum KeyframesStepValue {
 }
 
 /// A single step from a keyframe animation.
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct KeyframesStep {
     /// The percentage of the animation duration when this step starts.
@@ -235,7 +232,7 @@ impl KeyframesStep {
 /// of keyframes, in order.
 ///
 /// It only takes into account animable properties.
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct KeyframesAnimation {
     /// The difference steps of the animation.
diff --git a/components/style/properties/declaration_block.rs b/components/style/properties/declaration_block.rs
index b21fa79e3ec..243bc7cbc5c 100644
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@@ -49,12 +49,10 @@ impl Default for Importance {
 
 /// Overridden declarations are skipped.
 #[derive(Debug, PartialEq, Clone)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct PropertyDeclarationBlock {
     /// The group of declarations, along with their importance.
     ///
     /// Only deduplicated declarations appear here.
-    #[cfg_attr(feature = "servo", ignore_heap_size_of = "#7038")]
     pub declarations: Vec<(PropertyDeclaration, Importance)>,
 
     /// The number of entries in `self.declaration` with `Importance::Important`
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 642b56ff851..9b2c94798d5 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -563,7 +563,6 @@ impl ShorthandId {
 /// Servo's representation of a declared value for a given `T`, which is the
 /// declared value for that property.
 #[derive(Clone, PartialEq, Eq, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum DeclaredValue<T> {
     /// A known specified value from the stylesheet.
     Value(T),
@@ -574,8 +573,7 @@ pub enum DeclaredValue<T> {
 }
 
 /// An unparsed property value that contains `var()` functions.
-#[derive(Clone, PartialEq, Eq, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+#[derive(PartialEq, Eq, Debug)]
 pub struct UnparsedValue {
     /// The css serialization for this value.
     css: String,
@@ -854,7 +852,6 @@ impl ParsedDeclaration {
 
 /// Servo's representation for a property declaration.
 #[derive(PartialEq, Clone)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum PropertyDeclaration {
     % for property in data.longhands:
         /// ${property.name}
diff --git a/components/style/stylesheets.rs b/components/style/stylesheets.rs
index 6ee7b6843a0..758d81125b2 100644
--- a/components/style/stylesheets.rs
+++ b/components/style/stylesheets.rs
@@ -52,7 +52,6 @@ pub enum Origin {
 
 /// A set of namespaces applying to a given stylesheet.
 #[derive(Default, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub struct Namespaces {
     pub default: Option<Namespace>,
@@ -389,7 +388,6 @@ impl ToCss for CssRule {
 }
 
 #[derive(Debug, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 #[allow(missing_docs)]
 pub struct NamespaceRule {
     /// `None` for the default Namespace