diff --git a/components/layout/flow.rs b/components/layout/flow.rs
index 05512724843..fbcf7866931 100644
--- a/components/layout/flow.rs
+++ b/components/layout/flow.rs
@@ -44,7 +44,7 @@ use multicol::MulticolFlow;
 use parallel::FlowParallelInfo;
 use serde::ser::{Serialize, SerializeStruct, Serializer};
 use servo_geometry::{au_rect_to_f32_rect, f32_rect_to_au_rect, max_rect};
-use std::{fmt, mem, raw};
+use std::{fmt, mem};
 use std::iter::Zip;
 use std::slice::IterMut;
 use std::sync::Arc;
@@ -453,7 +453,7 @@ pub trait Flow: fmt::Debug + Sync + Send + 'static {
 #[allow(unsafe_code)]
 pub fn base<T: ?Sized + Flow>(this: &T) -> &BaseFlow {
     unsafe {
-        let obj = mem::transmute::<&&T, &raw::TraitObject>(&this);
+        let obj = mem::transmute::<&&T, &::TraitObject>(&this);
         mem::transmute::<*mut (), &BaseFlow>(obj.data)
     }
 }
@@ -467,7 +467,7 @@ pub fn child_iter<'a>(flow: &'a Flow) -> FlowListIterator {
 #[allow(unsafe_code)]
 pub fn mut_base<T: ?Sized + Flow>(this: &mut T) -> &mut BaseFlow {
     unsafe {
-        let obj = mem::transmute::<&&mut T, &raw::TraitObject>(&this);
+        let obj = mem::transmute::<&&mut T, &::TraitObject>(&this);
         mem::transmute::<*mut (), &mut BaseFlow>(obj.data)
     }
 }
@@ -1422,7 +1422,7 @@ impl OpaqueFlow {
     #[allow(unsafe_code)]
     pub fn from_flow(flow: &Flow) -> OpaqueFlow {
         unsafe {
-            let object = mem::transmute::<&Flow, raw::TraitObject>(flow);
+            let object = mem::transmute::<&Flow, ::TraitObject>(flow);
             OpaqueFlow(object.data as usize)
         }
     }
diff --git a/components/layout/lib.rs b/components/layout/lib.rs
index eb337c4b015..ab8beba722a 100644
--- a/components/layout/lib.rs
+++ b/components/layout/lib.rs
@@ -4,7 +4,6 @@
 
 #![deny(unsafe_code)]
 #![feature(box_patterns)]
-#![feature(raw)]
 
 extern crate app_units;
 extern crate atomic_refcell;
@@ -92,3 +91,12 @@ pub use self::data::LayoutData;
 // We can't use servo_arc for everything in layout, because the Flow stuff uses
 // weak references.
 use servo_arc::Arc as ServoArc;
+
+/// Stable copy of std::raw::TraitObject
+/// test/unit/layout/lib.rs asserts that the memory layout matches.
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct TraitObject {
+    pub data: *mut (),
+    pub vtable: *mut (),
+}
diff --git a/components/servo/Cargo.toml b/components/servo/Cargo.toml
index 27358a388b1..3f7f3c82598 100644
--- a/components/servo/Cargo.toml
+++ b/components/servo/Cargo.toml
@@ -20,8 +20,8 @@ googlevr = ["webvr/googlevr"]
 oculusvr = ["webvr/oculusvr"]
 unstable = [
     "euclid/unstable",
-    "msg/unstable",
     "gfx/unstable",
+    "msg/unstable",
     "profile/unstable",
 ]
 
diff --git a/tests/unit/layout/lib.rs b/tests/unit/layout/lib.rs
index a763135260a..bc1d9dfd464 100644
--- a/tests/unit/layout/lib.rs
+++ b/tests/unit/layout/lib.rs
@@ -2,7 +2,36 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#![feature(raw)]
+
 extern crate layout;
 #[macro_use] extern crate size_of_test;
 
 #[cfg(all(test, target_pointer_width = "64"))] mod size_of;
+
+use std::mem;
+use std::ptr;
+use std::raw;
+
+#[test]
+fn test_trait_object_layout() {
+    assert_eq!(mem::size_of::<raw::TraitObject>(), mem::size_of::<layout::TraitObject>());
+    let null: *mut () = ptr::null_mut();
+    let a = raw::TraitObject {
+        data: null,
+        vtable: null,
+    };
+    let b = layout::TraitObject {
+        data: null,
+        vtable: null,
+    };
+
+    fn offset<T, U>(struct_: &T, field: &U) -> usize {
+        let addr_struct = struct_ as *const T as usize;
+        let addr_field = field as *const U as usize;
+        addr_field - addr_struct
+    }
+
+    assert_eq!(offset(&a, &a.data), offset(&b, &b.data));
+    assert_eq!(offset(&a, &a.vtable), offset(&b, &b.vtable));
+}