diff --git a/components/selectors/parser.rs b/components/selectors/parser.rs
index a7f3d259fbd..c613d741eb6 100644
--- a/components/selectors/parser.rs
+++ b/components/selectors/parser.rs
@@ -62,7 +62,7 @@ macro_rules! with_all_bounds {
         /// NB: We need Clone so that we can derive(Clone) on struct with that
         /// are parameterized on SelectorImpl. See
         /// https://github.com/rust-lang/rust/issues/26925
-        pub trait SelectorImpl: Clone + Sized {
+        pub trait SelectorImpl: Clone + Sized + 'static {
             type AttrValue: $($InSelector)*;
             type Identifier: $($InSelector)* + PrecomputedHash;
             type ClassName: $($InSelector)* + PrecomputedHash;
diff --git a/components/servo_arc/lib.rs b/components/servo_arc/lib.rs
index 5d91c9bc44f..4fbc094d070 100644
--- a/components/servo_arc/lib.rs
+++ b/components/servo_arc/lib.rs
@@ -69,22 +69,64 @@ macro_rules! offset_of {
 /// necessarily) at _exactly_ `MAX_REFCOUNT + 1` references.
 const MAX_REFCOUNT: usize = (isize::MAX) as usize;
 
-pub struct Arc<T: ?Sized> {
-    // FIXME(bholley): When NonZero/Shared/Unique are stabilized, we should use
-    // Shared here to get the NonZero optimization. Gankro is working on this.
-    //
-    // If we need a compact Option<Arc<T>> beforehand, we can make a helper
-    // class that wraps the result of Arc::into_raw.
-    //
-    // https://github.com/rust-lang/rust/issues/27730
-    ptr: *mut ArcInner<T>,
+/// Wrapper type for pointers to get the non-zero optimization. When
+/// NonZero/Shared/Unique are stabilized, we should just use Shared
+/// here to get the same effect. Gankro is working on this in [1].
+///
+/// It's unfortunate that this needs to infect all the caller types
+/// with 'static. It would be nice to just use a &() and a PhantomData<T>
+/// instead, but then the compiler can't determine whether the &() should
+/// be thin or fat (which depends on whether or not T is sized). Given
+/// that this is all a temporary hack, this restriction is fine for now.
+///
+/// [1] https://github.com/rust-lang/rust/issues/27730
+pub struct NonZeroPtrMut<T: ?Sized + 'static>(&'static mut T);
+impl<T: ?Sized> NonZeroPtrMut<T> {
+    pub fn new(ptr: *mut T) -> Self {
+        assert!(!(ptr as *mut u8).is_null());
+        NonZeroPtrMut(unsafe { mem::transmute(ptr) })
+    }
+
+    pub fn ptr(&self) -> *mut T {
+        self.0 as *const T as *mut T
+    }
+}
+
+impl<T: ?Sized + 'static> Clone for NonZeroPtrMut<T> {
+    fn clone(&self) -> Self {
+        NonZeroPtrMut::new(self.ptr())
+    }
+}
+
+impl<T: ?Sized + 'static> fmt::Pointer for NonZeroPtrMut<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&self.ptr(), f)
+    }
+}
+
+impl<T: ?Sized + 'static> fmt::Debug for NonZeroPtrMut<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        <Self as fmt::Pointer>::fmt(self, f)
+    }
+}
+
+impl<T: ?Sized + 'static> PartialEq for NonZeroPtrMut<T> {
+    fn eq(&self, other: &Self) -> bool {
+        self.ptr() == other.ptr()
+    }
+}
+
+impl<T: ?Sized + 'static> Eq for NonZeroPtrMut<T> {}
+
+pub struct Arc<T: ?Sized + 'static> {
+    p: NonZeroPtrMut<ArcInner<T>>,
 }
 
 /// An Arc that is known to be uniquely owned
 ///
 /// This lets us build arcs that we can mutate before
 /// freezing, without needing to change the allocation
-pub struct UniqueArc<T: ?Sized>(Arc<T>);
+pub struct UniqueArc<T: ?Sized + 'static>(Arc<T>);
 
 impl<T> UniqueArc<T> {
     #[inline]
@@ -110,7 +152,7 @@ impl<T> Deref for UniqueArc<T> {
 impl<T> DerefMut for UniqueArc<T> {
     fn deref_mut(&mut self) -> &mut T {
         // We know this to be uniquely owned
-        unsafe { &mut (*self.0.ptr).data }
+        unsafe { &mut (*self.0.ptr()).data }
     }
 }
 
@@ -132,11 +174,11 @@ impl<T> Arc<T> {
             count: atomic::AtomicUsize::new(1),
             data: data,
         });
-        Arc { ptr: Box::into_raw(x) }
+        Arc { p: NonZeroPtrMut::new(Box::into_raw(x)) }
     }
 
     pub fn into_raw(this: Self) -> *const T {
-        let ptr = unsafe { &((*this.ptr).data) as *const _ };
+        let ptr = unsafe { &((*this.ptr()).data) as *const _ };
         mem::forget(this);
         ptr
     }
@@ -146,7 +188,7 @@ impl<T> Arc<T> {
         // to subtract the offset of the `data` field from the pointer.
         let ptr = (ptr as *const u8).offset(-offset_of!(ArcInner<T>, data));
         Arc {
-            ptr: ptr as *mut ArcInner<T>,
+            p: NonZeroPtrMut::new(ptr as *mut ArcInner<T>),
         }
     }
 }
@@ -159,19 +201,23 @@ impl<T: ?Sized> Arc<T> {
         // `ArcInner` structure itself is `Sync` because the inner data is
         // `Sync` as well, so we're ok loaning out an immutable pointer to these
         // contents.
-        unsafe { &*self.ptr }
+        unsafe { &*self.ptr() }
     }
 
     // Non-inlined part of `drop`. Just invokes the destructor.
     #[inline(never)]
     unsafe fn drop_slow(&mut self) {
-        let _ = Box::from_raw(self.ptr);
+        let _ = Box::from_raw(self.ptr());
     }
 
 
     #[inline]
     pub fn ptr_eq(this: &Self, other: &Self) -> bool {
-        this.ptr == other.ptr
+        this.ptr() == other.ptr()
+    }
+
+    fn ptr(&self) -> *mut ArcInner<T> {
+        self.p.ptr()
     }
 }
 
@@ -210,7 +256,7 @@ impl<T: ?Sized> Clone for Arc<T> {
             panic!();
         }
 
-        Arc { ptr: self.ptr }
+        Arc { p: NonZeroPtrMut::new(self.ptr()) }
     }
 }
 
@@ -237,7 +283,7 @@ impl<T: Clone> Arc<T> {
             // reference count is guaranteed to be 1 at this point, and we required
             // the Arc itself to be `mut`, so we're returning the only possible
             // reference to the inner data.
-            &mut (*this.ptr).data
+            &mut (*this.ptr()).data
         }
     }
 }
@@ -248,7 +294,7 @@ impl<T: ?Sized> Arc<T> {
         if this.is_unique() {
             unsafe {
                 // See make_mut() for documentation of the threadsafety here.
-                Some(&mut (*this.ptr).data)
+                Some(&mut (*this.ptr()).data)
             }
         } else {
             None
@@ -357,7 +403,7 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for Arc<T> {
 
 impl<T: ?Sized> fmt::Pointer for Arc<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Pointer::fmt(&self.ptr, f)
+        fmt::Pointer::fmt(&self.ptr(), f)
     }
 }
 
@@ -481,6 +527,8 @@ impl<H, T> Arc<HeaderSlice<H, [T]>> {
             //
             // To avoid alignment issues, we allocate words rather than bytes,
             // rounding up to the nearest word size.
+            assert!(mem::align_of::<T>() <= mem::align_of::<usize>(),
+                    "We don't handle over-aligned types");
             let words_to_allocate = divide_rounding_up(size, size_of::<usize>());
             let mut vec = Vec::<usize>::with_capacity(words_to_allocate);
             vec.set_len(words_to_allocate);
@@ -496,6 +544,9 @@ impl<H, T> Arc<HeaderSlice<H, [T]>> {
             ptr = fake_slice as *mut [T] as *mut ArcInner<HeaderSlice<H, [T]>>;
 
             // Write the data.
+            //
+            // Note that any panics here (i.e. from the iterator) are safe, since
+            // we'll just leak the uninitialized memory.
             ptr::write(&mut ((*ptr).count), atomic::AtomicUsize::new(1));
             ptr::write(&mut ((*ptr).data.header), header);
             let mut current: *mut T = &mut (*ptr).data.slice[0];
@@ -511,7 +562,7 @@ impl<H, T> Arc<HeaderSlice<H, [T]>> {
 
         // Return the fat Arc.
         assert_eq!(size_of::<Self>(), size_of::<usize>() * 2, "The Arc will be fat");
-        Arc { ptr: ptr }
+        Arc { p: NonZeroPtrMut::new(ptr) }
     }
 }
 
@@ -536,8 +587,9 @@ impl<H> HeaderWithLength<H> {
     }
 }
 
-pub struct ThinArc<H, T> {
-    ptr: *mut ArcInner<HeaderSlice<HeaderWithLength<H>, [T; 1]>>,
+type HeaderSliceWithLength<H, T> = HeaderSlice<HeaderWithLength<H>, T>;
+pub struct ThinArc<H: 'static, T: 'static> {
+    ptr: *mut ArcInner<HeaderSliceWithLength<H, [T; 1]>>,
 }
 
 unsafe impl<H: Sync + Send, T: Sync + Send> Send for ThinArc<H, T> {}
@@ -546,27 +598,27 @@ unsafe impl<H: Sync + Send, T: Sync + Send> Sync for ThinArc<H, T> {}
 // Synthesize a fat pointer from a thin pointer.
 //
 // See the comment around the analogous operation in from_header_and_iter.
-fn thin_to_thick<H, T>(thin: *mut ArcInner<HeaderSlice<HeaderWithLength<H>, [T; 1]>>)
-    -> *mut ArcInner<HeaderSlice<HeaderWithLength<H>, [T]>>
+fn thin_to_thick<H, T>(thin: *mut ArcInner<HeaderSliceWithLength<H, [T; 1]>>)
+    -> *mut ArcInner<HeaderSliceWithLength<H, [T]>>
 {
     let len = unsafe { (*thin).data.header.length };
     let fake_slice: *mut [T] = unsafe {
         slice::from_raw_parts_mut(thin as *mut T, len)
     };
 
-    fake_slice as *mut ArcInner<HeaderSlice<HeaderWithLength<H>, [T]>>
+    fake_slice as *mut ArcInner<HeaderSliceWithLength<H, [T]>>
 }
 
-impl<H, T> ThinArc<H, T> {
+impl<H: 'static, T: 'static> ThinArc<H, T> {
     /// Temporarily converts |self| into a bonafide Arc and exposes it to the
     /// provided callback. The refcount is not modified.
     #[inline(always)]
     pub fn with_arc<F, U>(&self, f: F) -> U
-        where F: FnOnce(&Arc<HeaderSlice<HeaderWithLength<H>, [T]>>) -> U
+        where F: FnOnce(&Arc<HeaderSliceWithLength<H, [T]>>) -> U
     {
         // Synthesize transient Arc, which never touches the refcount of the ArcInner.
         let transient = NoDrop::new(Arc {
-            ptr: thin_to_thick(self.ptr)
+            p: NonZeroPtrMut::new(thin_to_thick(self.ptr))
         });
 
         // Expose the transient Arc to the callback, which may clone it if it wants.
@@ -581,35 +633,35 @@ impl<H, T> ThinArc<H, T> {
 }
 
 impl<H, T> Deref for ThinArc<H, T> {
-    type Target = HeaderSlice<HeaderWithLength<H>, [T]>;
+    type Target = HeaderSliceWithLength<H, [T]>;
     fn deref(&self) -> &Self::Target {
         unsafe { &(*thin_to_thick(self.ptr)).data }
     }
 }
 
-impl<H, T> Clone for ThinArc<H, T> {
+impl<H: 'static, T: 'static> Clone for ThinArc<H, T> {
     fn clone(&self) -> Self {
         ThinArc::with_arc(self, |a| Arc::into_thin(a.clone()))
     }
 }
 
-impl<H, T> Drop for ThinArc<H, T> {
+impl<H: 'static, T: 'static> Drop for ThinArc<H, T> {
     fn drop(&mut self) {
         let _ = Arc::from_thin(ThinArc { ptr: self.ptr });
     }
 }
 
-impl<H, T> Arc<HeaderSlice<HeaderWithLength<H>, [T]>> {
+impl<H: 'static, T: 'static> Arc<HeaderSliceWithLength<H, [T]>> {
     /// Converts an Arc into a ThinArc. This consumes the Arc, so the refcount
     /// is not modified.
     pub fn into_thin(a: Self) -> ThinArc<H, T> {
         assert!(a.header.length == a.slice.len(),
                 "Length needs to be correct for ThinArc to work");
-        let fat_ptr: *mut ArcInner<HeaderSlice<HeaderWithLength<H>, [T]>> = a.ptr;
+        let fat_ptr: *mut ArcInner<HeaderSliceWithLength<H, [T]>> = a.ptr();
         mem::forget(a);
         let thin_ptr = fat_ptr as *mut [usize] as *mut usize;
         ThinArc {
-            ptr: thin_ptr as *mut ArcInner<HeaderSlice<HeaderWithLength<H>, [T; 1]>>
+            ptr: thin_ptr as *mut ArcInner<HeaderSliceWithLength<H, [T; 1]>>
         }
     }
 
@@ -619,12 +671,12 @@ impl<H, T> Arc<HeaderSlice<HeaderWithLength<H>, [T]>> {
         let ptr = thin_to_thick(a.ptr);
         mem::forget(a);
         Arc {
-            ptr: ptr
+            p: NonZeroPtrMut::new(ptr)
         }
     }
 }
 
-impl<H: PartialEq, T: PartialEq> PartialEq for ThinArc<H, T> {
+impl<H: PartialEq + 'static, T: PartialEq + 'static> PartialEq for ThinArc<H, T> {
     fn eq(&self, other: &ThinArc<H, T>) -> bool {
         ThinArc::with_arc(self, |a| {
             ThinArc::with_arc(other, |b| {
@@ -634,7 +686,7 @@ impl<H: PartialEq, T: PartialEq> PartialEq for ThinArc<H, T> {
     }
 }
 
-impl<H: Eq, T: Eq> Eq for ThinArc<H, T> {}
+impl<H: Eq + 'static, T: Eq + 'static> Eq for ThinArc<H, T> {}
 
 #[cfg(test)]
 mod tests {
@@ -649,13 +701,7 @@ mod tests {
 
     impl Drop for Canary {
         fn drop(&mut self) {
-            unsafe {
-                match *self {
-                    Canary(c) => {
-                        (*c).fetch_add(1, SeqCst);
-                    }
-                }
-            }
+            unsafe { (*self.0).fetch_add(1, SeqCst); }
         }
     }
 
diff --git a/components/style/gecko_bindings/sugar/ownership.rs b/components/style/gecko_bindings/sugar/ownership.rs
index 6c4746013b3..0b5111b3870 100644
--- a/components/style/gecko_bindings/sugar/ownership.rs
+++ b/components/style/gecko_bindings/sugar/ownership.rs
@@ -11,7 +11,7 @@ use std::ptr;
 use stylearc::Arc;
 
 /// Indicates that a given Servo type has a corresponding Gecko FFI type.
-pub unsafe trait HasFFI : Sized {
+pub unsafe trait HasFFI : Sized + 'static {
     /// The corresponding Gecko type that this rust type represents.
     ///
     /// See the examples in `components/style/gecko/conversions.rs`.
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 4114b2f2b22..1ec0dee0ef7 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -2193,7 +2193,7 @@ pub fn get_writing_mode(inheritedbox_style: &style_structs::InheritedBox) -> Wri
 }
 
 /// A reference to a style struct of the parent, or our own style struct.
-pub enum StyleStructRef<'a, T: 'a> {
+pub enum StyleStructRef<'a, T: 'static> {
     /// A borrowed struct from the parent, for example, for inheriting style.
     Borrowed(&'a Arc<T>),
     /// An owned struct, that we've already mutated.
diff --git a/components/style/rule_tree/mod.rs b/components/style/rule_tree/mod.rs
index 2557b4c77e5..37e7334b9db 100644
--- a/components/style/rule_tree/mod.rs
+++ b/components/style/rule_tree/mod.rs
@@ -14,7 +14,7 @@ use smallvec::SmallVec;
 use std::io::{self, Write};
 use std::ptr;
 use std::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
-use stylearc::Arc;
+use stylearc::{Arc, NonZeroPtrMut};
 use stylesheets::StyleRule;
 use stylist::ApplicableDeclarationList;
 use thread_state;
@@ -637,7 +637,7 @@ impl RuleNode {
             current: if first_child.is_null() {
                 None
             } else {
-                Some(WeakRuleNode { ptr: first_child })
+                Some(WeakRuleNode::from_ptr(first_child))
             }
         }
     }
@@ -645,15 +645,13 @@ impl RuleNode {
 
 #[derive(Clone)]
 struct WeakRuleNode {
-    ptr: *mut RuleNode,
+    p: NonZeroPtrMut<RuleNode>,
 }
 
 /// A strong reference to a rule node.
 #[derive(Debug, PartialEq)]
 pub struct StrongRuleNode {
-    // TODO: Mark this as NonZero once stable to save space inside Option.
-    // https://github.com/rust-lang/rust/issues/27730
-    ptr: *mut RuleNode,
+    p: NonZeroPtrMut<RuleNode>,
 }
 
 #[cfg(feature = "servo")]
@@ -670,15 +668,17 @@ impl StrongRuleNode {
 
         debug!("Creating rule node: {:p}", ptr);
 
+        StrongRuleNode::from_ptr(ptr)
+    }
+
+    fn from_ptr(ptr: *mut RuleNode) -> Self {
         StrongRuleNode {
-            ptr: ptr,
+            p: NonZeroPtrMut::new(ptr)
         }
     }
 
     fn downgrade(&self) -> WeakRuleNode {
-        WeakRuleNode {
-            ptr: self.ptr,
-        }
+        WeakRuleNode::from_ptr(self.ptr())
     }
 
     fn next_sibling(&self) -> Option<WeakRuleNode> {
@@ -688,9 +688,7 @@ impl StrongRuleNode {
         if ptr.is_null() {
             None
         } else {
-            Some(WeakRuleNode {
-                ptr: ptr
-            })
+            Some(WeakRuleNode::from_ptr(ptr))
         }
     }
 
@@ -748,7 +746,7 @@ impl StrongRuleNode {
 
                 // Existing is not null: some thread inserted a child node since
                 // we accessed `last`.
-                strong = WeakRuleNode { ptr: existing }.upgrade();
+                strong = WeakRuleNode::from_ptr(existing).upgrade();
 
                 if strong.get().source.as_ref().unwrap().ptr_equals(&source) {
                     // That node happens to be for the same style source, use
@@ -764,15 +762,15 @@ impl StrongRuleNode {
 
     /// Raw pointer to the RuleNode
     pub fn ptr(&self) -> *mut RuleNode {
-        self.ptr
+        self.p.ptr()
     }
 
     fn get(&self) -> &RuleNode {
         if cfg!(debug_assertions) {
-            let node = unsafe { &*self.ptr };
+            let node = unsafe { &*self.ptr() };
             assert!(node.refcount.load(Ordering::Relaxed) > 0);
         }
-        unsafe { &*self.ptr }
+        unsafe { &*self.ptr() }
     }
 
     /// Get the style source corresponding to this rule node. May return `None`
@@ -808,7 +806,7 @@ impl StrongRuleNode {
     unsafe fn pop_from_free_list(&self) -> Option<WeakRuleNode> {
         // NB: This can run from the root node destructor, so we can't use
         // `get()`, since it asserts the refcount is bigger than zero.
-        let me = &*self.ptr;
+        let me = &*self.ptr();
 
         debug_assert!(me.is_root());
 
@@ -831,7 +829,7 @@ impl StrongRuleNode {
         debug_assert!(!current.is_null(),
                       "Multiple threads are operating on the free list at the \
                        same time?");
-        debug_assert!(current != self.ptr,
+        debug_assert!(current != self.ptr(),
                       "How did the root end up in the free list?");
 
         let next = (*current).next_free.swap(ptr::null_mut(), Ordering::Relaxed);
@@ -843,17 +841,17 @@ impl StrongRuleNode {
 
         debug!("Popping from free list: cur: {:?}, next: {:?}", current, next);
 
-        Some(WeakRuleNode { ptr: current })
+        Some(WeakRuleNode::from_ptr(current))
     }
 
     unsafe fn assert_free_list_has_no_duplicates_or_null(&self) {
         assert!(cfg!(debug_assertions), "This is an expensive check!");
         use std::collections::HashSet;
 
-        let me = &*self.ptr;
+        let me = &*self.ptr();
         assert!(me.is_root());
 
-        let mut current = self.ptr;
+        let mut current = self.ptr();
         let mut seen = HashSet::new();
         while current != FREE_LIST_SENTINEL {
             let next = (*current).next_free.load(Ordering::Relaxed);
@@ -872,7 +870,7 @@ impl StrongRuleNode {
 
         // NB: This can run from the root node destructor, so we can't use
         // `get()`, since it asserts the refcount is bigger than zero.
-        let me = &*self.ptr;
+        let me = &*self.ptr();
 
         debug_assert!(me.is_root(), "Can't call GC on a non-root node!");
 
@@ -1237,19 +1235,17 @@ impl Clone for StrongRuleNode {
         debug!("{:?}: {:?}+", self.ptr(), self.get().refcount.load(Ordering::Relaxed));
         debug_assert!(self.get().refcount.load(Ordering::Relaxed) > 0);
         self.get().refcount.fetch_add(1, Ordering::Relaxed);
-        StrongRuleNode {
-            ptr: self.ptr,
-        }
+        StrongRuleNode::from_ptr(self.ptr())
     }
 }
 
 impl Drop for StrongRuleNode {
     fn drop(&mut self) {
-        let node = unsafe { &*self.ptr };
+        let node = unsafe { &*self.ptr() };
 
         debug!("{:?}: {:?}-", self.ptr(), node.refcount.load(Ordering::Relaxed));
         debug!("Dropping node: {:?}, root: {:?}, parent: {:?}",
-               self.ptr,
+               self.ptr(),
                node.root.as_ref().map(|r| r.ptr()),
                node.parent.as_ref().map(|p| p.ptr()));
         let should_drop = {
@@ -1330,9 +1326,7 @@ impl Drop for StrongRuleNode {
 
 impl<'a> From<&'a StrongRuleNode> for WeakRuleNode {
     fn from(node: &'a StrongRuleNode) -> Self {
-        WeakRuleNode {
-            ptr: node.ptr(),
-        }
+        WeakRuleNode::from_ptr(node.ptr())
     }
 }
 
@@ -1340,15 +1334,19 @@ impl WeakRuleNode {
     fn upgrade(&self) -> StrongRuleNode {
         debug!("Upgrading weak node: {:p}", self.ptr());
 
-        let node = unsafe { &*self.ptr };
+        let node = unsafe { &*self.ptr() };
         node.refcount.fetch_add(1, Ordering::Relaxed);
-        StrongRuleNode {
-            ptr: self.ptr,
+        StrongRuleNode::from_ptr(self.ptr())
+    }
+
+    fn from_ptr(ptr: *mut RuleNode) -> Self {
+        WeakRuleNode {
+            p: NonZeroPtrMut::new(ptr)
         }
     }
 
     fn ptr(&self) -> *mut RuleNode {
-        self.ptr
+        self.p.ptr()
     }
 }
 
diff --git a/tests/unit/script/size_of.rs b/tests/unit/script/size_of.rs
index 3368271d8e1..c7c04b4aac1 100644
--- a/tests/unit/script/size_of.rs
+++ b/tests/unit/script/size_of.rs
@@ -31,10 +31,10 @@ macro_rules! sizeof_checker (
 // Update the sizes here
 sizeof_checker!(size_event_target, EventTarget, 40);
 sizeof_checker!(size_node, Node, 184);
-sizeof_checker!(size_element, Element, 352);
-sizeof_checker!(size_htmlelement, HTMLElement, 368);
-sizeof_checker!(size_div, HTMLDivElement, 368);
-sizeof_checker!(size_span, HTMLSpanElement, 368);
+sizeof_checker!(size_element, Element, 344);
+sizeof_checker!(size_htmlelement, HTMLElement, 360);
+sizeof_checker!(size_div, HTMLDivElement, 360);
+sizeof_checker!(size_span, HTMLSpanElement, 360);
 sizeof_checker!(size_text, Text, 216);
 sizeof_checker!(size_characterdata, CharacterData, 216);
 sizeof_checker!(size_servothreadsafelayoutnode, ServoThreadSafeLayoutNode, 16);
diff --git a/tests/unit/stylo/size_of.rs b/tests/unit/stylo/size_of.rs
index 3344a65c075..31b6d70b32f 100644
--- a/tests/unit/stylo/size_of.rs
+++ b/tests/unit/stylo/size_of.rs
@@ -3,9 +3,13 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use selectors::gecko_like_types as dummies;
+use servo_arc::Arc;
 use std::mem::{size_of, align_of};
 use style;
+use style::data::{ComputedStyle, ElementData, ElementStyles};
 use style::gecko::selector_parser as real;
+use style::properties::ComputedValues;
+use style::rule_tree::StrongRuleNode;
 
 #[test]
 fn size_of_selectors_dummy_types() {
@@ -24,6 +28,12 @@ fn size_of_selectors_dummy_types() {
 // selectors (with the inline hashes) with as few cache misses as possible.
 size_of_test!(test_size_of_rule, style::stylist::Rule, 40);
 
+size_of_test!(test_size_of_option_arc_cv, Option<Arc<ComputedValues>>, 8);
+size_of_test!(test_size_of_option_rule_node, Option<StrongRuleNode>, 8);
+size_of_test!(test_size_of_computed_style, ComputedStyle, 32);
+size_of_test!(test_size_of_element_styles, ElementStyles, 48);
+size_of_test!(test_size_of_element_data, ElementData, 56);
+
 size_of_test!(test_size_of_property_declaration, style::properties::PropertyDeclaration, 32);
 
 // This is huge, but we allocate it on the stack and then never move it,