diff --git a/components/layout/context.rs b/components/layout/context.rs
index dd88741aed5..b329a20221d 100644
--- a/components/layout/context.rs
+++ b/components/layout/context.rs
@@ -99,24 +99,24 @@ impl<'a> LayoutContext<'a> {
     #[inline(always)]
     pub fn font_context<'a>(&'a self) -> &'a mut FontContext {
         unsafe {
-            let cached_context = &*self.cached_local_layout_context;
-            mem::transmute(&cached_context.font_context)
+            let cached_context = &mut *self.cached_local_layout_context;
+            &mut cached_context.font_context
         }
     }
 
     #[inline(always)]
     pub fn applicable_declarations_cache<'a>(&'a self) -> &'a mut ApplicableDeclarationsCache {
         unsafe {
-            let cached_context = &*self.cached_local_layout_context;
-            mem::transmute(&cached_context.applicable_declarations_cache)
+            let cached_context = &mut *self.cached_local_layout_context;
+            &mut cached_context.applicable_declarations_cache
         }
     }
 
     #[inline(always)]
     pub fn style_sharing_candidate_cache<'a>(&'a self) -> &'a mut StyleSharingCandidateCache {
         unsafe {
-            let cached_context = &*self.cached_local_layout_context;
-            mem::transmute(&cached_context.style_sharing_candidate_cache)
+            let cached_context = &mut *self.cached_local_layout_context;
+            &mut cached_context.style_sharing_candidate_cache
         }
     }
 }
diff --git a/components/layout/css/matching.rs b/components/layout/css/matching.rs
index e453d36f7ae..8606c575146 100644
--- a/components/layout/css/matching.rs
+++ b/components/layout/css/matching.rs
@@ -55,13 +55,9 @@ pub struct ApplicableDeclarationsCacheEntry {
 }
 
 impl ApplicableDeclarationsCacheEntry {
-    fn new(slice: &[DeclarationBlock]) -> ApplicableDeclarationsCacheEntry {
-        let mut entry_declarations = Vec::new();
-        for declarations in slice.iter() {
-            entry_declarations.push(declarations.clone());
-        }
+    fn new(declarations: Vec<DeclarationBlock>) -> ApplicableDeclarationsCacheEntry {
         ApplicableDeclarationsCacheEntry {
-            declarations: entry_declarations,
+            declarations: declarations,
         }
     }
 }
@@ -138,7 +134,7 @@ impl ApplicableDeclarationsCache {
         }
     }
 
-    fn insert(&mut self, declarations: &[DeclarationBlock], style: Arc<ComputedValues>) {
+    fn insert(&mut self, declarations: Vec<DeclarationBlock>, style: Arc<ComputedValues>) {
         self.cache.insert(ApplicableDeclarationsCacheEntry::new(declarations), style)
     }
 }
@@ -438,7 +434,7 @@ impl<'ln> PrivateMatchMethods for LayoutNode<'ln> {
 
         // Cache the resolved style if it was cacheable.
         if cacheable {
-            applicable_declarations_cache.insert(applicable_declarations, this_style.clone());
+            applicable_declarations_cache.insert(applicable_declarations.to_vec(), this_style.clone());
         }
 
         // Calculate style difference and write.