Issue #1742 - Part 1: Refactor rooting base class templates

Based on Bug 1325406

21 files changed, 227 insertions, 484 deletions

diff --git a/js/public/GCHashTable.h b/js/public/GCHashTable.h
index 4de1c39a81..3e647ed100 100644
--- a/js/public/GCHashTable.h
+++ b/js/public/GCHashTable.h
@@ -133,13 +133,13 @@ class GCRekeyableHashMap : public JS::GCHashMap<Key, Value, HashPolicy, AllocPol
     }
 };
 
-template <typename Outer, typename... Args>
-class GCHashMapOperations
+template <typename Wrapper, typename... Args>
+class WrappedPtrOperations<JS::GCHashMap<Args...>, Wrapper>
 {
     using Map = JS::GCHashMap<Args...>;
     using Lookup = typename Map::Lookup;
 
-    const Map& map() const { return static_cast<const Outer*>(this)->get(); }
+    const Map& map() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     using AddPtr = typename Map::AddPtr;
@@ -162,18 +162,18 @@ class GCHashMapOperations
     }
 };
 
-template <typename Outer, typename... Args>
-class MutableGCHashMapOperations
-  : public GCHashMapOperations<Outer, Args...>
+template <typename Wrapper, typename... Args>
+class MutableWrappedPtrOperations<JS::GCHashMap<Args...>, Wrapper>
+  : public WrappedPtrOperations<JS::GCHashMap<Args...>, Wrapper>
 {
     using Map = JS::GCHashMap<Args...>;
     using Lookup = typename Map::Lookup;
 
-    Map& map() { return static_cast<Outer*>(this)->get(); }
+    Map& map() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     using AddPtr = typename Map::AddPtr;
-    struct Enum : public Map::Enum { explicit Enum(Outer& o) : Map::Enum(o.map()) {} };
+    struct Enum : public Map::Enum { explicit Enum(Wrapper& o) : Map::Enum(o.map()) {} };
     using Ptr = typename Map::Ptr;
     using Range = typename Map::Range;
 
@@ -210,26 +210,6 @@ class MutableGCHashMapOperations
     }
 };
 
-template <typename A, typename B, typename C, typename D, typename E>
-class RootedBase<JS::GCHashMap<A,B,C,D,E>>
-  : public MutableGCHashMapOperations<JS::Rooted<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
-{};
-
-template <typename A, typename B, typename C, typename D, typename E>
-class MutableHandleBase<JS::GCHashMap<A,B,C,D,E>>
-  : public MutableGCHashMapOperations<JS::MutableHandle<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
-{};
-
-template <typename A, typename B, typename C, typename D, typename E>
-class HandleBase<JS::GCHashMap<A,B,C,D,E>>
-  : public GCHashMapOperations<JS::Handle<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
-{};
-
-template <typename A, typename B, typename C, typename D, typename E>
-class WeakCacheBase<JS::GCHashMap<A,B,C,D,E>>
-  : public MutableGCHashMapOperations<JS::WeakCache<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
-{};
-
 } // namespace js
 
 namespace JS {
@@ -291,13 +271,13 @@ class GCHashSet : public js::HashSet<T, HashPolicy, AllocPolicy>
 
 namespace js {
 
-template <typename Outer, typename... Args>
-class GCHashSetOperations
+template <typename Wrapper, typename... Args>
+class WrappedPtrOperations<JS::GCHashSet<Args...>, Wrapper>
 {
     using Set = JS::GCHashSet<Args...>;
     using Lookup = typename Set::Lookup;
 
-    const Set& set() const { return static_cast<const Outer*>(this)->get(); }
+    const Set& set() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     using AddPtr = typename Set::AddPtr;
@@ -321,19 +301,19 @@ class GCHashSetOperations
     }
 };
 
-template <typename Outer, typename... Args>
-class MutableGCHashSetOperations
-  : public GCHashSetOperations<Outer, Args...>
+template <typename Wrapper, typename... Args>
+class MutableWrappedPtrOperations<JS::GCHashSet<Args...>, Wrapper>
+  : public WrappedPtrOperations<JS::GCHashSet<Args...>, Wrapper>
 {
     using Set = JS::GCHashSet<Args...>;
     using Lookup = typename Set::Lookup;
 
-    Set& set() { return static_cast<Outer*>(this)->get(); }
+    Set& set() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     using AddPtr = typename Set::AddPtr;
     using Entry = typename Set::Entry;
-    struct Enum : public Set::Enum { explicit Enum(Outer& o) : Set::Enum(o.set()) {} };
+    struct Enum : public Set::Enum { explicit Enum(Wrapper& o) : Set::Enum(o.set()) {} };
     using Ptr = typename Set::Ptr;
     using Range = typename Set::Range;
 
@@ -369,30 +349,6 @@ class MutableGCHashSetOperations
     }
 };
 
-template <typename T, typename HP, typename AP>
-class RootedBase<JS::GCHashSet<T, HP, AP>>
-  : public MutableGCHashSetOperations<JS::Rooted<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
-{
-};
-
-template <typename T, typename HP, typename AP>
-class MutableHandleBase<JS::GCHashSet<T, HP, AP>>
-  : public MutableGCHashSetOperations<JS::MutableHandle<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
-{
-};
-
-template <typename T, typename HP, typename AP>
-class HandleBase<JS::GCHashSet<T, HP, AP>>
-  : public GCHashSetOperations<JS::Handle<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
-{
-};
-
-template <typename T, typename HP, typename AP>
-class WeakCacheBase<JS::GCHashSet<T, HP, AP>>
-  : public MutableGCHashSetOperations<JS::WeakCache<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
-{
-};
-
 } /* namespace js */
 
 #endif /* GCHashTable_h */
diff --git a/js/public/GCVariant.h b/js/public/GCVariant.h
index 43f2957fee..3ec40df5ca 100644
--- a/js/public/GCVariant.h
+++ b/js/public/GCVariant.h
@@ -123,13 +123,13 @@ struct GCPolicy<mozilla::Variant<Ts...>>
 
 namespace js {
 
-template <typename Outer, typename... Ts>
-class GCVariantOperations
+template <typename Wrapper, typename... Ts>
+class WrappedPtrOperations<mozilla::Variant<Ts...>, Wrapper>
 {
     using Impl = JS::detail::GCVariantImplementation<Ts...>;
     using Variant = mozilla::Variant<Ts...>;
 
-    const Variant& variant() const { return static_cast<const Outer*>(this)->get(); }
+    const Variant& variant() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     template <typename T>
@@ -149,15 +149,15 @@ class GCVariantOperations
     }
 };
 
-template <typename Outer, typename... Ts>
-class MutableGCVariantOperations
-  : public GCVariantOperations<Outer, Ts...>
+template <typename Wrapper, typename... Ts>
+class MutableWrappedPtrOperations<mozilla::Variant<Ts...>, Wrapper>
+  : public WrappedPtrOperations<mozilla::Variant<Ts...>, Wrapper>
 {
     using Impl = JS::detail::GCVariantImplementation<Ts...>;
     using Variant = mozilla::Variant<Ts...>;
 
-    const Variant& variant() const { return static_cast<const Outer*>(this)->get(); }
-    Variant& variant() { return static_cast<Outer*>(this)->get(); }
+    const Variant& variant() const { return static_cast<const Wrapper*>(this)->get(); }
+    Variant& variant() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     template <typename T>
@@ -172,26 +172,6 @@ class MutableGCVariantOperations
     }
 };
 
-template <typename... Ts>
-class RootedBase<mozilla::Variant<Ts...>>
-  : public MutableGCVariantOperations<JS::Rooted<mozilla::Variant<Ts...>>, Ts...>
-{ };
-
-template <typename... Ts>
-class MutableHandleBase<mozilla::Variant<Ts...>>
-  : public MutableGCVariantOperations<JS::MutableHandle<mozilla::Variant<Ts...>>, Ts...>
-{ };
-
-template <typename... Ts>
-class HandleBase<mozilla::Variant<Ts...>>
-  : public GCVariantOperations<JS::Handle<mozilla::Variant<Ts...>>, Ts...>
-{ };
-
-template <typename... Ts>
-class PersistentRootedBase<mozilla::Variant<Ts...>>
-  : public MutableGCVariantOperations<JS::PersistentRooted<mozilla::Variant<Ts...>>, Ts...>
-{ };
-
 } // namespace js
 
 #endif // js_GCVariant_h
diff --git a/js/public/GCVector.h b/js/public/GCVector.h
index 1c99252617..4acf0d1fc5 100644
--- a/js/public/GCVector.h
+++ b/js/public/GCVector.h
@@ -134,11 +134,11 @@ class GCVector
 
 namespace js {
 
-template <typename Outer, typename T, size_t Capacity, typename AllocPolicy>
-class GCVectorOperations
+template <typename Wrapper, typename T, size_t Capacity, typename AllocPolicy>
+class WrappedPtrOperations<JS::GCVector<T, Capacity, AllocPolicy>, Wrapper>
 {
     using Vec = JS::GCVector<T, Capacity, AllocPolicy>;
-    const Vec& vec() const { return static_cast<const Outer*>(this)->get(); }
+    const Vec& vec() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     const AllocPolicy& allocPolicy() const { return vec().allocPolicy(); }
@@ -154,13 +154,13 @@ class GCVectorOperations
     }
 };
 
-template <typename Outer, typename T, size_t Capacity, typename AllocPolicy>
-class MutableGCVectorOperations
-  : public GCVectorOperations<Outer, T, Capacity, AllocPolicy>
+template <typename Wrapper, typename T, size_t Capacity, typename AllocPolicy>
+class MutableWrappedPtrOperations<JS::GCVector<T, Capacity, AllocPolicy>, Wrapper>
+  : public WrappedPtrOperations<JS::GCVector<T, Capacity, AllocPolicy>, Wrapper>
 {
     using Vec = JS::GCVector<T, Capacity, AllocPolicy>;
-    const Vec& vec() const { return static_cast<const Outer*>(this)->get(); }
-    Vec& vec() { return static_cast<Outer*>(this)->get(); }
+    const Vec& vec() const { return static_cast<const Wrapper*>(this)->get(); }
+    Vec& vec() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     const AllocPolicy& allocPolicy() const { return vec().allocPolicy(); }
@@ -223,26 +223,6 @@ class MutableGCVectorOperations
     void erase(T* aBegin, T* aEnd) { vec().erase(aBegin, aEnd); }
 };
 
-template <typename T, size_t N, typename AP>
-class RootedBase<JS::GCVector<T,N,AP>>
-  : public MutableGCVectorOperations<JS::Rooted<JS::GCVector<T,N,AP>>, T,N,AP>
-{};
-
-template <typename T, size_t N, typename AP>
-class MutableHandleBase<JS::GCVector<T,N,AP>>
-  : public MutableGCVectorOperations<JS::MutableHandle<JS::GCVector<T,N,AP>>, T,N,AP>
-{};
-
-template <typename T, size_t N, typename AP>
-class HandleBase<JS::GCVector<T,N,AP>>
-  : public GCVectorOperations<JS::Handle<JS::GCVector<T,N,AP>>, T,N,AP>
-{};
-
-template <typename T, size_t N, typename AP>
-class PersistentRootedBase<JS::GCVector<T,N,AP>>
-  : public MutableGCVectorOperations<JS::PersistentRooted<JS::GCVector<T,N,AP>>, T,N,AP>
-{};
-
 } // namespace js
 
 #endif // js_GCVector_h
diff --git a/js/public/RootingAPI.h b/js/public/RootingAPI.h
index 5f0740d53a..120e1fcde0 100644
--- a/js/public/RootingAPI.h
+++ b/js/public/RootingAPI.h
@@ -112,17 +112,23 @@ template <typename T>
 struct BarrierMethods {
 };
 
-template <typename T>
-class RootedBase {};
+template <typename Element, typename Wrapper>
+class WrappedPtrOperations {};
 
-template <typename T>
-class HandleBase {};
+template <typename Element, typename Wrapper>
+class MutableWrappedPtrOperations : public WrappedPtrOperations<Element, Wrapper> {};
 
-template <typename T>
-class MutableHandleBase {};
+template <typename T, typename Wrapper>
+class RootedBase : public MutableWrappedPtrOperations<T, Wrapper> {};
 
-template <typename T>
-class HeapBase {};
+template <typename T, typename Wrapper>
+class HandleBase : public WrappedPtrOperations<T, Wrapper> {};
+
+template <typename T, typename Wrapper>
+class MutableHandleBase : public MutableWrappedPtrOperations<T, Wrapper> {};
+
+template <typename T, typename Wrapper>
+class HeapBase : public MutableWrappedPtrOperations<T, Wrapper> {};
 
 // Cannot use FOR_EACH_HEAP_ABLE_GC_POINTER_TYPE, as this would import too many macros into scope
 template <typename T> struct IsHeapConstructibleType    { static constexpr bool value = false; };
@@ -132,8 +138,8 @@ FOR_EACH_PUBLIC_GC_POINTER_TYPE(DECLARE_IS_HEAP_CONSTRUCTIBLE_TYPE)
 FOR_EACH_PUBLIC_TAGGED_GC_POINTER_TYPE(DECLARE_IS_HEAP_CONSTRUCTIBLE_TYPE)
 #undef DECLARE_IS_HEAP_CONSTRUCTIBLE_TYPE
 
-template <typename T>
-class PersistentRootedBase {};
+template <typename T, typename Wrapper>
+class PersistentRootedBase : public MutableWrappedPtrOperations<T, Wrapper> {};
 
 static void* const ConstNullValue = nullptr;
 
@@ -230,7 +236,7 @@ AssertGCThingIsNotAnObjectSubclass(js::gc::Cell* cell) {}
  * Type T must be a public GC pointer type.
  */
 template <typename T>
-class MOZ_NON_MEMMOVABLE Heap : public js::HeapBase<T>
+class MOZ_NON_MEMMOVABLE Heap : public js::HeapBase<T, Heap<T>>
 {
     // Please note: this can actually also be used by nsXBLMaybeCompiled<T>, for legacy reasons.
     static_assert(js::IsHeapConstructibleType<T>::value,
@@ -367,7 +373,7 @@ ScriptIsMarkedGray(const Heap<JSScript*>& script)
  *  - It is not possible to store flag bits in a Heap<T>.
  */
 template <typename T>
-class TenuredHeap : public js::HeapBase<T>
+class TenuredHeap : public js::HeapBase<T, TenuredHeap<T>>
 {
   public:
     TenuredHeap() : bits(0) {
@@ -451,7 +457,7 @@ class TenuredHeap : public js::HeapBase<T>
  * specialization, define a HandleBase<T> specialization containing them.
  */
 template <typename T>
-class MOZ_NONHEAP_CLASS Handle : public js::HandleBase<T>
+class MOZ_NONHEAP_CLASS Handle : public js::HandleBase<T, Handle<T>>
 {
     friend class JS::MutableHandle<T>;
 
@@ -540,7 +546,7 @@ class MOZ_NONHEAP_CLASS Handle : public js::HandleBase<T>
  * them.
  */
 template <typename T>
-class MOZ_STACK_CLASS MutableHandle : public js::MutableHandleBase<T>
+class MOZ_STACK_CLASS MutableHandle : public js::MutableHandleBase<T, MutableHandle<T>>
 {
   public:
     inline MOZ_IMPLICIT MutableHandle(Rooted<T>* root);
@@ -753,7 +759,7 @@ namespace JS {
  * specialization, define a RootedBase<T> specialization containing them.
  */
 template <typename T>
-class MOZ_RAII Rooted : public js::RootedBase<T>
+class MOZ_RAII Rooted : public js::RootedBase<T, Rooted<T>>
 {
     inline void registerWithRootLists(js::RootedListHeads& roots) {
         this->stack = &roots[JS::MapTypeToRootKind<T>::kind];
@@ -853,8 +859,8 @@ namespace js {
  *   Rooted<StringObject*> rooted(cx, &obj->as<StringObject*>());
  *   Handle<StringObject*> h = rooted;
  */
-template <>
-class RootedBase<JSObject*>
+template <typename Container>
+class RootedBase<JSObject*, Container> : public MutableWrappedPtrOperations<JSObject*, Container>
 {
   public:
     template <class U>
@@ -871,8 +877,8 @@ class RootedBase<JSObject*>
  *   Rooted<StringObject*> rooted(cx, &obj->as<StringObject*>());
  *   Handle<StringObject*> h = rooted;
  */
-template <>
-class HandleBase<JSObject*>
+template <typename Container>
+class HandleBase<JSObject*, Container> : public WrappedPtrOperations<JSObject*, Container>
 {
   public:
     template <class U>
@@ -881,7 +887,7 @@ class HandleBase<JSObject*>
 
 /** Interface substitute for Rooted<T> which does not root the variable's memory. */
 template <typename T>
-class MOZ_RAII FakeRooted : public RootedBase<T>
+class MOZ_RAII FakeRooted : public RootedBase<T, FakeRooted<T>>
 {
   public:
     template <typename CX>
@@ -908,7 +914,7 @@ class MOZ_RAII FakeRooted : public RootedBase<T>
 
 /** Interface substitute for MutableHandle<T> which is not required to point to rooted memory. */
 template <typename T>
-class FakeMutableHandle : public js::MutableHandleBase<T>
+class FakeMutableHandle : public js::MutableHandleBase<T, FakeMutableHandle<T>>
 {
   public:
     MOZ_IMPLICIT FakeMutableHandle(T* t) {
@@ -1075,7 +1081,7 @@ MutableHandle<T>::MutableHandle(PersistentRooted<T>* root)
  * marked when the object itself is marked.
  */
 template<typename T>
-class PersistentRooted : public js::PersistentRootedBase<T>,
+class PersistentRooted : public js::RootedBase<T, PersistentRooted<T>>,
                          private mozilla::LinkedListElement<PersistentRooted<T>>
 {
     using ListBase = mozilla::LinkedListElement<PersistentRooted<T>>;
@@ -1240,10 +1246,10 @@ class JS_PUBLIC_API(ObjectPtr)
 
 namespace js {
 
-template <typename Outer, typename T, typename D>
-class UniquePtrOperations
+template <typename T, typename D, typename Container>
+class WrappedPtrOperations<UniquePtr<T, D>, Container>
 {
-    const UniquePtr<T, D>& uniquePtr() const { return static_cast<const Outer*>(this)->get(); }
+    const UniquePtr<T, D>& uniquePtr() const { return static_cast<const Container*>(this)->get(); }
 
   public:
     explicit operator bool() const { return !!uniquePtr(); }
@@ -1252,36 +1258,17 @@ class UniquePtrOperations
     T& operator*() const { return *uniquePtr(); }
 };
 
-template <typename Outer, typename T, typename D>
-class MutableUniquePtrOperations : public UniquePtrOperations<Outer, T, D>
+template <typename T, typename D, typename Container>
+class MutableWrappedPtrOperations<UniquePtr<T, D>, Container>
+  : public WrappedPtrOperations<UniquePtr<T, D>, Container>
 {
-    UniquePtr<T, D>& uniquePtr() { return static_cast<Outer*>(this)->get(); }
+    UniquePtr<T, D>& uniquePtr() { return static_cast<Container*>(this)->get(); }
 
   public:
     MOZ_MUST_USE typename UniquePtr<T, D>::Pointer release() { return uniquePtr().release(); }
     void reset(T* ptr = T()) { uniquePtr().reset(ptr); }
 };
 
-template <typename T, typename D>
-class RootedBase<UniquePtr<T, D>>
-  : public MutableUniquePtrOperations<JS::Rooted<UniquePtr<T, D>>, T, D>
-{ };
-
-template <typename T, typename D>
-class MutableHandleBase<UniquePtr<T, D>>
-  : public MutableUniquePtrOperations<JS::MutableHandle<UniquePtr<T, D>>, T, D>
-{ };
-
-template <typename T, typename D>
-class HandleBase<UniquePtr<T, D>>
-  : public UniquePtrOperations<JS::Handle<UniquePtr<T, D>>, T, D>
-{ };
-
-template <typename T, typename D>
-class PersistentRootedBase<UniquePtr<T, D>>
-  : public MutableUniquePtrOperations<JS::PersistentRooted<UniquePtr<T, D>>, T, D>
-{ };
-
 namespace gc {
 
 template <typename T, typename TraceCallbacks>
diff --git a/js/public/SweepingAPI.h b/js/public/SweepingAPI.h
index 39abb0fc0e..bbc1ec279b 100644
--- a/js/public/SweepingAPI.h
+++ b/js/public/SweepingAPI.h
@@ -8,11 +8,6 @@
 
 #include "js/HeapAPI.h"
 
-namespace js {
-template <typename T>
-class WeakCacheBase {};
-} // namespace js
-
 namespace JS {
 template <typename T> class WeakCache;
 
@@ -24,7 +19,7 @@ RegisterWeakCache(JS::Zone* zone, JS::WeakCache<void*>* cachep);
 // A WeakCache stores the given Sweepable container and links itself into a
 // list of such caches that are swept during each GC.
 template <typename T>
-class WeakCache : public js::WeakCacheBase<T>,
+class WeakCache : public js::MutableWrappedPtrOperations<T, WeakCache<T>>,
                   private mozilla::LinkedListElement<WeakCache<T>>
 {
     friend class mozilla::LinkedListElement<WeakCache<T>>;
diff --git a/js/public/Value.h b/js/public/Value.h
index 087d178efd..c645f07733 100644
--- a/js/public/Value.h
+++ b/js/public/Value.h
@@ -1340,20 +1340,18 @@ struct BarrierMethods<JS::Value>
     }
 };
 
-template <class Outer> class MutableValueOperations;
+template <class Wrapper> class MutableValueOperations;
 
 /**
  * A class designed for CRTP use in implementing the non-mutating parts of the
- * Value interface in Value-like classes.  Outer must be a class inheriting
- * ValueOperations<Outer> with a visible get() method returning a const
- * reference to the Value abstracted by Outer.
+ * Value interface in Value-like classes.  Wrapper must be a class inheriting
+ * ValueOperations<Wrapper> with a visible get() method returning a const
+ * reference to the Value abstracted by Wrapper.
  */
-template <class Outer>
-class ValueOperations
+template <class Wrapper>
+class WrappedPtrOperations<JS::Value, Wrapper>
 {
-    friend class MutableValueOperations<Outer>;
-
-    const JS::Value& value() const { return static_cast<const Outer*>(this)->get(); }
+    const JS::Value& value() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     bool isUndefined() const { return value().isUndefined(); }
@@ -1398,17 +1396,17 @@ class ValueOperations
 
 /**
  * A class designed for CRTP use in implementing all the mutating parts of the
- * Value interface in Value-like classes.  Outer must be a class inheriting
- * MutableValueOperations<Outer> with visible get() methods returning const and
- * non-const references to the Value abstracted by Outer.
+ * Value interface in Value-like classes.  Wrapper must be a class inheriting
+ * MutableWrappedPtrOperations<Wrapper> with visible get() methods returning const and
+ * non-const references to the Value abstracted by Wrapper.
  */
-template <class Outer>
-class MutableValueOperations : public ValueOperations<Outer>
+template <class Wrapper>
+class MutableWrappedPtrOperations<JS::Value, Wrapper> : public WrappedPtrOperations<JS::Value, Wrapper>
 {
   protected:
     void set(const JS::Value& v) {
       // Call Outer::set to trigger any barriers.
-      static_cast<Outer*>(this)->set(v);
+      static_cast<Wrapper*>(this)->set(v);
     }
 
   public:
@@ -1434,13 +1432,9 @@ class MutableValueOperations : public ValueOperations<Outer>
  * Augment the generic Heap<T> interface when T = Value with
  * type-querying, value-extracting, and mutating operations.
  */
-template <>
-class HeapBase<JS::Value> : public MutableValueOperations<JS::Heap<JS::Value> >
+template <typename Wrapper>
+class HeapBase<JS::Value, Wrapper> : public MutableWrappedPtrOperations<JS::Value, Wrapper>
 {
-    typedef JS::Heap<JS::Value> Outer;
-
-    friend class ValueOperations<Outer>;
-
   public:
     void setNumber(uint32_t ui) {
         if (ui > JSVAL_INT_MAX) {
@@ -1460,22 +1454,6 @@ class HeapBase<JS::Value> : public MutableValueOperations<JS::Heap<JS::Value> >
     }
 };
 
-template <>
-class HandleBase<JS::Value> : public ValueOperations<JS::Handle<JS::Value> >
-{};
-
-template <>
-class MutableHandleBase<JS::Value> : public MutableValueOperations<JS::MutableHandle<JS::Value> >
-{};
-
-template <>
-class RootedBase<JS::Value> : public MutableValueOperations<JS::Rooted<JS::Value> >
-{};
-
-template <>
-class PersistentRootedBase<JS::Value> : public MutableValueOperations<JS::PersistentRooted<JS::Value>>
-{};
-
 /*
  * If the Value is a GC pointer type, convert to that type and call |f| with
  * the pointer. If the Value is not a GC type, calls F::defaultValue.
diff --git a/js/src/builtin/MapObject.h b/js/src/builtin/MapObject.h
index 5382adfd25..a9f685ea00 100644
--- a/js/src/builtin/MapObject.h
+++ b/js/src/builtin/MapObject.h
@@ -52,14 +52,22 @@ class HashableValue
     }
 };
 
-template <>
-class RootedBase<HashableValue> {
+template <typename Wrapper>
+class WrappedPtrOperations<HashableValue, Wrapper>
+{
   public:
-    MOZ_MUST_USE bool setValue(JSContext* cx, HandleValue v) {
-        return static_cast<JS::Rooted<HashableValue>*>(this)->get().setValue(cx, v);
-    }
     Value value() const {
-        return static_cast<const JS::Rooted<HashableValue>*>(this)->get().get();
+        return static_cast<const Wrapper*>(this)->get().get();
+    }
+};
+
+template <typename Wrapper>
+class MutableWrappedPtrOperations<HashableValue, Wrapper>
+  : public WrappedPtrOperations<HashableValue, Wrapper>
+{
+  public:
+    MOZ_MUST_USE bool setValue(JSContext* cx, HandleValue v) {
+        return static_cast<Wrapper*>(this)->get().setValue(cx, v);
     }
 };
 
diff --git a/js/src/ds/TraceableFifo.h b/js/src/ds/TraceableFifo.h
index 04f67da151..0f94b93cbd 100644
--- a/js/src/ds/TraceableFifo.h
+++ b/js/src/ds/TraceableFifo.h
@@ -51,11 +51,11 @@ class TraceableFifo : public js::Fifo<T, MinInlineCapacity, AllocPolicy>
     }
 };
 
-template <typename Outer, typename T, size_t Capacity, typename AllocPolicy>
-class TraceableFifoOperations
+template <typename Wrapper, typename T, size_t Capacity, typename AllocPolicy>
+class WrappedPtrOperations<TraceableFifo<T, Capacity, AllocPolicy>, Wrapper>
 {
     using TF = TraceableFifo<T, Capacity, AllocPolicy>;
-    const TF& fifo() const { return static_cast<const Outer*>(this)->extract(); }
+    const TF& fifo() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     size_t length() const { return fifo().length(); }
@@ -63,12 +63,12 @@ class TraceableFifoOperations
     const T& front() const { return fifo().front(); }
 };
 
-template <typename Outer, typename T, size_t Capacity, typename AllocPolicy>
-class MutableTraceableFifoOperations
-  : public TraceableFifoOperations<Outer, T, Capacity, AllocPolicy>
+template <typename Wrapper, typename T, size_t Capacity, typename AllocPolicy>
+class MutableWrappedPtrOperations<TraceableFifo<T, Capacity, AllocPolicy>, Wrapper>
+  : public WrappedPtrOperations<TraceableFifo<T, Capacity, AllocPolicy>, Wrapper>
 {
     using TF = TraceableFifo<T, Capacity, AllocPolicy>;
-    TF& fifo() { return static_cast<Outer*>(this)->extract(); }
+    TF& fifo() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     T& front() { return fifo().front(); }
@@ -82,46 +82,6 @@ class MutableTraceableFifoOperations
     void clear() { fifo().clear(); }
 };
 
-template <typename A, size_t B, typename C>
-class RootedBase<TraceableFifo<A,B,C>>
-  : public MutableTraceableFifoOperations<JS::Rooted<TraceableFifo<A,B,C>>, A,B,C>
-{
-    using TF = TraceableFifo<A,B,C>;
-
-    friend class TraceableFifoOperations<JS::Rooted<TF>, A,B,C>;
-    const TF& extract() const { return *static_cast<const JS::Rooted<TF>*>(this)->address(); }
-
-    friend class MutableTraceableFifoOperations<JS::Rooted<TF>, A,B,C>;
-    TF& extract() { return *static_cast<JS::Rooted<TF>*>(this)->address(); }
-};
-
-template <typename A, size_t B, typename C>
-class MutableHandleBase<TraceableFifo<A,B,C>>
-  : public MutableTraceableFifoOperations<JS::MutableHandle<TraceableFifo<A,B,C>>, A,B,C>
-{
-    using TF = TraceableFifo<A,B,C>;
-
-    friend class TraceableFifoOperations<JS::MutableHandle<TF>, A,B,C>;
-    const TF& extract() const {
-        return *static_cast<const JS::MutableHandle<TF>*>(this)->address();
-    }
-
-    friend class MutableTraceableFifoOperations<JS::MutableHandle<TF>, A,B,C>;
-    TF& extract() { return *static_cast<JS::MutableHandle<TF>*>(this)->address(); }
-};
-
-template <typename A, size_t B, typename C>
-class HandleBase<TraceableFifo<A,B,C>>
-  : public TraceableFifoOperations<JS::Handle<TraceableFifo<A,B,C>>, A,B,C>
-{
-    using TF = TraceableFifo<A,B,C>;
-
-    friend class TraceableFifoOperations<JS::Handle<TF>, A,B,C>;
-    const TF& extract() const {
-        return *static_cast<const JS::Handle<TF>*>(this)->address();
-    }
-};
-
 } // namespace js
 
 #endif // js_TraceableFifo_h
diff --git a/js/src/gc/Barrier.h b/js/src/gc/Barrier.h
index 681ccc9c4c..d10fb4321c 100644
--- a/js/src/gc/Barrier.h
+++ b/js/src/gc/Barrier.h
@@ -324,18 +324,12 @@ struct InternalBarrierMethods<jsid>
     static void postBarrier(jsid* idp, jsid prev, jsid next) {}
 };
 
-// Barrier classes can use Mixins to add methods to a set of barrier
-// instantiations, to make the barriered thing look and feel more like the
-// thing itself.
-template <typename T>
-class BarrieredBaseMixins {};
-
 // Base class of all barrier types.
 //
 // This is marked non-memmovable since post barriers added by derived classes
 // can add pointers to class instances to the store buffer.
 template <typename T>
-class MOZ_NON_MEMMOVABLE BarrieredBase : public BarrieredBaseMixins<T>
+class MOZ_NON_MEMMOVABLE BarrieredBase
 {
   protected:
     // BarrieredBase is not directly instantiable.
@@ -356,9 +350,12 @@ class MOZ_NON_MEMMOVABLE BarrieredBase : public BarrieredBaseMixins<T>
 
 // Base class for barriered pointer types that intercept only writes.
 template <class T>
-class WriteBarrieredBase : public BarrieredBase<T>
+class WriteBarrieredBase : public BarrieredBase<T>,
+                           public WrappedPtrOperations<T, WriteBarrieredBase<T>>
 {
   protected:
+    using BarrieredBase<T>::value;
+
     // WriteBarrieredBase is not directly instantiable.
     explicit WriteBarrieredBase(const T& v) : BarrieredBase<T>(v) {}
 
@@ -580,8 +577,12 @@ class ReadBarrieredBase : public BarrieredBase<T>
 // insert manual post-barriers on the table for rekeying if the key is based in
 // any way on the address of the object.
 template <typename T>
-class ReadBarriered : public ReadBarrieredBase<T>
+class ReadBarriered : public ReadBarrieredBase<T>,
+                      public WrappedPtrOperations<T, ReadBarriered<T>>
 {
+  protected:
+    using ReadBarrieredBase<T>::value;
+
   public:
     ReadBarriered() : ReadBarrieredBase<T>(JS::GCPolicy<T>::initial()) {}
 
@@ -649,12 +650,6 @@ class ReadBarriered : public ReadBarrieredBase<T>
 template <typename T>
 using WeakRef = ReadBarriered<T>;
 
-// Add Value operations to all Barrier types. Note, this must be defined before
-// HeapSlot for HeapSlot's base to get these operations.
-template <>
-class BarrieredBaseMixins<JS::Value> : public ValueOperations<WriteBarrieredBase<JS::Value>>
-{};
-
 // A pre- and post-barriered Value that is specialized to be aware that it
 // resides in a slots or elements vector. This allows it to be relocated in
 // memory, but with substantially less overhead than a HeapPtr.
diff --git a/js/src/jsapi-tests/testGCExactRooting.cpp b/js/src/jsapi-tests/testGCExactRooting.cpp
index aff65014a9..6d41d374b5 100644
--- a/js/src/jsapi-tests/testGCExactRooting.cpp
+++ b/js/src/jsapi-tests/testGCExactRooting.cpp
@@ -56,19 +56,10 @@ struct MyContainer
 };
 
 namespace js {
-template <>
-struct RootedBase<MyContainer> {
-    HeapPtr<JSObject*>& obj() { return static_cast<Rooted<MyContainer>*>(this)->get().obj; }
-    HeapPtr<JSString*>& str() { return static_cast<Rooted<MyContainer>*>(this)->get().str; }
-};
-template <>
-struct PersistentRootedBase<MyContainer> {
-    HeapPtr<JSObject*>& obj() {
-        return static_cast<PersistentRooted<MyContainer>*>(this)->get().obj;
-    }
-    HeapPtr<JSString*>& str() {
-        return static_cast<PersistentRooted<MyContainer>*>(this)->get().str;
-    }
+template <typename Wrapper>
+struct MutableWrappedPtrOperations<MyContainer, Wrapper> {
+    HeapPtr<JSObject*>& obj() { return static_cast<Wrapper*>(this)->get().obj; }
+    HeapPtr<JSString*>& str() { return static_cast<Wrapper*>(this)->get().str; }
 };
 } // namespace js
 
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 1eecdbf749..8e70cc152b 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -2546,10 +2546,14 @@ struct JS_PUBLIC_API(PropertyDescriptor) {
     void trace(JSTracer* trc);
 };
 
-template <typename Outer>
-class PropertyDescriptorOperations
+} // namespace JS
+
+namespace js {
+
+template <typename Wrapper>
+class WrappedPtrOperations<JS::PropertyDescriptor, Wrapper>
 {
-    const PropertyDescriptor& desc() const { return static_cast<const Outer*>(this)->get(); }
+    const JS::PropertyDescriptor& desc() const { return static_cast<const Wrapper*>(this)->get(); }
 
     bool has(unsigned bit) const {
         MOZ_ASSERT(bit != 0);
@@ -2678,10 +2682,11 @@ class PropertyDescriptorOperations
     }
 };
 
-template <typename Outer>
-class MutablePropertyDescriptorOperations : public PropertyDescriptorOperations<Outer>
+template <typename Wrapper>
+class MutableWrappedPtrOperations<JS::PropertyDescriptor, Wrapper>
+    : public js::WrappedPtrOperations<JS::PropertyDescriptor, Wrapper>
 {
-    PropertyDescriptor& desc() { return static_cast<Outer*>(this)->get(); }
+    JS::PropertyDescriptor& desc() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     void clear() {
@@ -2692,7 +2697,7 @@ class MutablePropertyDescriptorOperations : public PropertyDescriptorOperations<
         value().setUndefined();
     }
 
-    void initFields(HandleObject obj, HandleValue v, unsigned attrs,
+    void initFields(JS::HandleObject obj, JS::HandleValue v, unsigned attrs,
                     JSGetterOp getterOp, JSSetterOp setterOp) {
         MOZ_ASSERT(getterOp != JS_PropertyStub);
         MOZ_ASSERT(setterOp != JS_StrictPropertyStub);
@@ -2704,7 +2709,7 @@ class MutablePropertyDescriptorOperations : public PropertyDescriptorOperations<
         setSetter(setterOp);
     }
 
-    void assign(PropertyDescriptor& other) {
+    void assign(JS::PropertyDescriptor& other) {
         object().set(other.obj);
         setAttributes(other.attrs);
         setGetter(other.getter);
@@ -2712,7 +2717,7 @@ class MutablePropertyDescriptorOperations : public PropertyDescriptorOperations<
         value().set(other.value);
     }
 
-    void setDataDescriptor(HandleValue v, unsigned attrs) {
+    void setDataDescriptor(JS::HandleValue v, unsigned attrs) {
         MOZ_ASSERT((attrs & ~(JSPROP_ENUMERATE |
                               JSPROP_PERMANENT |
                               JSPROP_READONLY |
@@ -2787,26 +2792,7 @@ class MutablePropertyDescriptorOperations : public PropertyDescriptorOperations<
     }
 };
 
-} /* namespace JS */
-
-namespace js {
-
-template <>
-class RootedBase<JS::PropertyDescriptor>
-  : public JS::MutablePropertyDescriptorOperations<JS::Rooted<JS::PropertyDescriptor>>
-{};
-
-template <>
-class HandleBase<JS::PropertyDescriptor>
-  : public JS::PropertyDescriptorOperations<JS::Handle<JS::PropertyDescriptor>>
-{};
-
-template <>
-class MutableHandleBase<JS::PropertyDescriptor>
-  : public JS::MutablePropertyDescriptorOperations<JS::MutableHandle<JS::PropertyDescriptor>>
-{};
-
-} /* namespace js */
+} // namespace js
 
 namespace JS {
 
diff --git a/js/src/jscompartment.cpp b/js/src/jscompartment.cpp
index ebf2d178fc..5e33f27f7d 100644
--- a/js/src/jscompartment.cpp
+++ b/js/src/jscompartment.cpp
@@ -722,8 +722,9 @@ JSCompartment::sweepAfterMinorGC(JSTracer* trc)
 {
     globalWriteBarriered = 0;
 
-    if (innerViews.needsSweepAfterMinorGC())
-        innerViews.sweepAfterMinorGC();
+    InnerViewTable& table = innerViews.get();
+    if (table.needsSweepAfterMinorGC())
+        table.sweepAfterMinorGC();
 
     crossCompartmentWrappers.sweepAfterMinorGC(trc);
 }
diff --git a/js/src/jsobj.h b/js/src/jsobj.h
index ca48f8de7c..52be7e8188 100644
--- a/js/src/jsobj.h
+++ b/js/src/jsobj.h
@@ -587,21 +587,23 @@ class JSObject : public js::gc::Cell
     void operator=(const JSObject& other) = delete;
 };
 
-template <class U>
+template <typename Wrapper>
+template <typename U>
 MOZ_ALWAYS_INLINE JS::Handle<U*>
-js::RootedBase<JSObject*>::as() const
+js::RootedBase<JSObject*, Wrapper>::as() const
 {
-    const JS::Rooted<JSObject*>& self = *static_cast<const JS::Rooted<JSObject*>*>(this);
-    MOZ_ASSERT(self->is<U>());
+    const Wrapper& self = *static_cast<const Wrapper*>(this);
+    MOZ_ASSERT(self->template is<U>());
     return Handle<U*>::fromMarkedLocation(reinterpret_cast<U* const*>(self.address()));
 }
 
+template <typename Wrapper>
 template <class U>
 MOZ_ALWAYS_INLINE JS::Handle<U*>
-js::HandleBase<JSObject*>::as() const
+js::HandleBase<JSObject*, Wrapper>::as() const
 {
     const JS::Handle<JSObject*>& self = *static_cast<const JS::Handle<JSObject*>*>(this);
-    MOZ_ASSERT(self->is<U>());
+    MOZ_ASSERT(self->template is<U>());
     return Handle<U*>::fromMarkedLocation(reinterpret_cast<U* const*>(self.address()));
 }
 
diff --git a/js/src/vm/ArrayBufferObject.cpp b/js/src/vm/ArrayBufferObject.cpp
index 1de3d3b1ec..5d355ada9d 100644
--- a/js/src/vm/ArrayBufferObject.cpp
+++ b/js/src/vm/ArrayBufferObject.cpp
@@ -352,7 +352,7 @@ ArrayBufferObject::detach(JSContext* cx, Handle<ArrayBufferObject*> buffer,
     // Update all views of the buffer to account for the buffer having been
     // detached, and clear the buffer's data and list of views.
 
-    auto& innerViews = cx->compartment()->innerViews;
+    auto& innerViews = cx->compartment()->innerViews.get();
     if (InnerViewTable::ViewVector* views = innerViews.maybeViewsUnbarriered(buffer)) {
         for (size_t i = 0; i < views->length(); i++)
             NoteViewBufferWasDetached((*views)[i], newContents, cx);
@@ -427,7 +427,7 @@ ArrayBufferObject::changeContents(JSContext* cx, BufferContents newContents,
     setNewData(cx->runtime()->defaultFreeOp(), newContents, ownsState);
 
     // Update all views.
-    auto& innerViews = cx->compartment()->innerViews;
+    auto& innerViews = cx->compartment()->innerViews.get();
     if (InnerViewTable::ViewVector* views = innerViews.maybeViewsUnbarriered(this)) {
         for (size_t i = 0; i < views->length(); i++)
             changeViewContents(cx, (*views)[i], oldDataPointer, newContents);
diff --git a/js/src/vm/ArrayBufferObject.h b/js/src/vm/ArrayBufferObject.h
index e6dbd30961..87dce34ba1 100644
--- a/js/src/vm/ArrayBufferObject.h
+++ b/js/src/vm/ArrayBufferObject.h
@@ -541,7 +541,6 @@ class InnerViewTable
     typedef Vector<ArrayBufferViewObject*, 1, SystemAllocPolicy> ViewVector;
 
     friend class ArrayBufferObject;
-    friend class WeakCacheBase<InnerViewTable>;
 
   private:
     struct MapGCPolicy {
@@ -602,23 +601,15 @@ class InnerViewTable
     size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf);
 };
 
-template <>
-class WeakCacheBase<InnerViewTable>
+template <typename Wrapper>
+class MutableWrappedPtrOperations<InnerViewTable, Wrapper>
+    : public WrappedPtrOperations<InnerViewTable, Wrapper>
 {
     InnerViewTable& table() {
-        return static_cast<JS::WeakCache<InnerViewTable>*>(this)->get();
-    }
-    const InnerViewTable& table() const {
-        return static_cast<const JS::WeakCache<InnerViewTable>*>(this)->get();
+        return static_cast<Wrapper*>(this)->get();
     }
 
   public:
-    InnerViewTable::ViewVector* maybeViewsUnbarriered(ArrayBufferObject* obj) {
-        return table().maybeViewsUnbarriered(obj);
-    }
-    void removeViews(ArrayBufferObject* obj) { table().removeViews(obj); }
-    void sweepAfterMinorGC() { table().sweepAfterMinorGC(); }
-    bool needsSweepAfterMinorGC() const { return table().needsSweepAfterMinorGC(); }
     size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) {
         return table().sizeOfExcludingThis(mallocSizeOf);
     }
diff --git a/js/src/vm/Interpreter.cpp b/js/src/vm/Interpreter.cpp
index 56f715e2be..7e3f2a7f1b 100644
--- a/js/src/vm/Interpreter.cpp
+++ b/js/src/vm/Interpreter.cpp
@@ -1613,11 +1613,7 @@ GetSuperEnvFunction(JSContext* cx, InterpreterRegs& regs)
  */
 
 template<typename T>
-class ReservedRootedBase {
-};
-
-template<typename T>
-class ReservedRooted : public ReservedRootedBase<T>
+class ReservedRooted : public RootedBase<T, ReservedRooted<T>>
 {
     Rooted<T>* savedRoot;
 
@@ -1645,14 +1641,6 @@ class ReservedRooted : public ReservedRootedBase<T>
     DECLARE_POINTER_ASSIGN_OPS(ReservedRooted, T)
 };
 
-template <>
-class ReservedRootedBase<Value> : public ValueOperations<ReservedRooted<Value>>
-{};
-
-template <>
-class ReservedRootedBase<Scope*> : public ScopeCastOperation<ReservedRooted<Scope*>>
-{};
-
 static MOZ_NEVER_INLINE bool
 Interpret(JSContext* cx, RunState& state)
 {
diff --git a/js/src/vm/JSONParser.h b/js/src/vm/JSONParser.h
index 6f91391db0..70ed86f58e 100644
--- a/js/src/vm/JSONParser.h
+++ b/js/src/vm/JSONParser.h
@@ -255,10 +255,13 @@ class MOZ_STACK_CLASS JSONParser : public JSONParserBase
     void operator=(const JSONParser& other) = delete;
 };
 
-template <typename CharT>
-struct RootedBase<JSONParser<CharT>> {
+template <typename CharT, typename Wrapper>
+class MutableWrappedPtrOperations<JSONParser<CharT>, Wrapper>
+  : public WrappedPtrOperations<JSONParser<CharT>, Wrapper>
+{
+  public:
     bool parse(MutableHandleValue vp) {
-        return static_cast<Rooted<JSONParser<CharT>>*>(this)->get().parse(vp);
+        return static_cast<Wrapper*>(this)->get().parse(vp);
     }
 };
 
diff --git a/js/src/vm/SavedStacks.h b/js/src/vm/SavedStacks.h
index c6bda2831b..3ea6c40874 100644
--- a/js/src/vm/SavedStacks.h
+++ b/js/src/vm/SavedStacks.h
@@ -265,24 +265,6 @@ class SavedStacks {
         uint32_t column;
     };
 
-    template <typename Outer>
-    struct LocationValueOperations {
-        JSAtom* source() const { return loc().source; }
-        size_t line() const { return loc().line; }
-        uint32_t column() const { return loc().column; }
-      private:
-        const LocationValue& loc() const { return static_cast<const Outer*>(this)->get(); }
-    };
-
-    template <typename Outer>
-    struct MutableLocationValueOperations : public LocationValueOperations<Outer> {
-        void setSource(JSAtom* v) { loc().source = v; }
-        void setLine(size_t v) { loc().line = v; }
-        void setColumn(uint32_t v) { loc().column = v; }
-      private:
-        LocationValue& loc() { return static_cast<Outer*>(this)->get(); }
-    };
-
   private:
     struct PCLocationHasher : public DefaultHasher<PCKey> {
         using ScriptPtrHasher = DefaultHasher<JSScript*>;
@@ -313,15 +295,32 @@ class SavedStacks {
                                   MutableHandle<LocationValue> locationp);
 };
 
-template <>
-class RootedBase<SavedStacks::LocationValue>
-  : public SavedStacks::MutableLocationValueOperations<JS::Rooted<SavedStacks::LocationValue>>
-{};
+template <typename Wrapper>
+struct WrappedPtrOperations<SavedStacks::LocationValue, Wrapper>
+{
+    JSAtom* source() const { return loc().source; }
+    size_t line() const { return loc().line; }
+    uint32_t column() const { return loc().column; }
+
+  private:
+    const SavedStacks::LocationValue& loc() const {
+        return static_cast<const Wrapper*>(this)->get();
+    }
+};
+
+template <typename Wrapper>
+struct MutableWrappedPtrOperations<SavedStacks::LocationValue, Wrapper>
+    : public WrappedPtrOperations<SavedStacks::LocationValue, Wrapper>
+{
+    void setSource(JSAtom* v) { loc().source = v; }
+    void setLine(size_t v) { loc().line = v; }
+    void setColumn(uint32_t v) { loc().column = v; }
 
-template <>
-class MutableHandleBase<SavedStacks::LocationValue>
-  : public SavedStacks::MutableLocationValueOperations<JS::MutableHandle<SavedStacks::LocationValue>>
-{};
+  private:
+    SavedStacks::LocationValue& loc() {
+        return static_cast<Wrapper*>(this)->get();
+    }
+};
 
 UTF8CharsZ
 BuildUTF8StackString(JSContext* cx, HandleObject stack);
diff --git a/js/src/vm/Scope.h b/js/src/vm/Scope.h
index 4f0edcc133..fc1419bb89 100644
--- a/js/src/vm/Scope.h
+++ b/js/src/vm/Scope.h
@@ -22,6 +22,7 @@
 namespace js {
 
 class ModuleObject;
+class Scope;
 
 enum class BindingKind : uint8_t
 {
@@ -224,6 +225,21 @@ class BindingLocation
 };
 
 //
+// Allow using is<T> and as<T> on Rooted<Scope*> and Handle<Scope*>.
+//
+template <typename Wrapper>
+class WrappedPtrOperations<Scope*, Wrapper>
+{
+  public:
+    template <class U>
+    JS::Handle<U*> as() const {
+        const Wrapper& self = *static_cast<const Wrapper*>(this);
+        MOZ_ASSERT_IF(self, self->template is<U>());
+        return Handle<U*>::fromMarkedLocation(reinterpret_cast<U* const*>(self.address()));
+    }
+};
+
+//
 // The base class of all Scopes.
 //
 class Scope : public js::gc::TenuredCell
@@ -1338,10 +1354,10 @@ class MOZ_STACK_CLASS ScopeIter
 // Specializations of Rooted containers for the iterators.
 //
 
-template <typename Outer>
-class BindingIterOperations
+template <typename Wrapper>
+class WrappedPtrOperations<BindingIter, Wrapper>
 {
-    const BindingIter& iter() const { return static_cast<const Outer*>(this)->get(); }
+    const BindingIter& iter() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     bool done() const { return iter().done(); }
@@ -1361,19 +1377,20 @@ class BindingIterOperations
     uint32_t nextEnvironmentSlot() const { return iter().nextEnvironmentSlot(); }
 };
 
-template <typename Outer>
-class MutableBindingIterOperations : public BindingIterOperations<Outer>
+template <typename Wrapper>
+class MutableWrappedPtrOperations<BindingIter, Wrapper>
+  : public WrappedPtrOperations<BindingIter, Wrapper>
 {
-    BindingIter& iter() { return static_cast<Outer*>(this)->get(); }
+    BindingIter& iter() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     void operator++(int) { iter().operator++(1); }
 };
 
-template <typename Outer>
-class ScopeIterOperations
+template <typename Wrapper>
+class WrappedPtrOperations<ScopeIter, Wrapper>
 {
-    const ScopeIter& iter() const { return static_cast<const Outer*>(this)->get(); }
+    const ScopeIter& iter() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     bool done() const { return iter().done(); }
@@ -1384,69 +1401,16 @@ class ScopeIterOperations
     bool hasSyntacticEnvironment() const { return iter().hasSyntacticEnvironment(); }
 };
 
-template <typename Outer>
-class MutableScopeIterOperations : public ScopeIterOperations<Outer>
+template <typename Wrapper>
+class MutableWrappedPtrOperations<ScopeIter, Wrapper>
+  : public WrappedPtrOperations<ScopeIter, Wrapper>
 {
-    ScopeIter& iter() { return static_cast<Outer*>(this)->get(); }
+    ScopeIter& iter() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     void operator++(int) { iter().operator++(1); }
 };
 
-#define SPECIALIZE_ROOTING_CONTAINERS(Iter, BaseIter)                    \
-    template <>                                                          \
-    class RootedBase<Iter>                                               \
-      : public Mutable##BaseIter##Operations<JS::Rooted<Iter>>           \
-    { };                                                                 \
-                                                                         \
-    template <>                                                          \
-    class MutableHandleBase<Iter>                                        \
-      : public Mutable##BaseIter##Operations<JS::MutableHandle<Iter>>    \
-    { };                                                                 \
-                                                                         \
-    template <>                                                          \
-    class HandleBase<Iter>                                               \
-      : public BaseIter##Operations<JS::Handle<Iter>>                    \
-    { };                                                                 \
-                                                                         \
-    template <>                                                          \
-    class PersistentRootedBase<Iter>                                     \
-      : public Mutable##BaseIter##Operations<JS::PersistentRooted<Iter>> \
-    { }
-
-SPECIALIZE_ROOTING_CONTAINERS(BindingIter, BindingIter);
-SPECIALIZE_ROOTING_CONTAINERS(PositionalFormalParameterIter, BindingIter);
-SPECIALIZE_ROOTING_CONTAINERS(ScopeIter, ScopeIter);
-
-#undef SPECIALIZE_ROOTING_CONTAINERS
-
-//
-// Allow using is<T> and as<T> on Rooted<Scope*> and Handle<Scope*>.
-//
-
-template <typename Outer>
-struct ScopeCastOperation
-{
-    template <class U>
-    JS::Handle<U*> as() const {
-        const Outer& self = *static_cast<const Outer*>(this);
-        MOZ_ASSERT_IF(self, self->template is<U>());
-        return Handle<U*>::fromMarkedLocation(reinterpret_cast<U* const*>(self.address()));
-    }
-};
-
-template <>
-class RootedBase<Scope*> : public ScopeCastOperation<JS::Rooted<Scope*>>
-{ };
-
-template <>
-class HandleBase<Scope*> : public ScopeCastOperation<JS::Handle<Scope*>>
-{ };
-
-template <>
-class MutableHandleBase<Scope*> : public ScopeCastOperation<JS::MutableHandle<Scope*>>
-{ };
-
 } // namespace js
 
 namespace JS {
diff --git a/js/src/vm/Shape.h b/js/src/vm/Shape.h
index 52b9197da6..b292bd58f2 100644
--- a/js/src/vm/Shape.h
+++ b/js/src/vm/Shape.h
@@ -1264,9 +1264,10 @@ struct InitialShapeEntry
 
     bool needsSweep() {
         Shape* ushape = shape.unbarrieredGet();
-        JSObject* protoObj = proto.proto().raw();
+        TaggedProto uproto = proto.proto().unbarrieredGet();
+        JSObject* protoObj = uproto.raw();
         return (gc::IsAboutToBeFinalizedUnbarriered(&ushape) ||
-                (proto.proto().isObject() && gc::IsAboutToBeFinalizedUnbarriered(&protoObj)));
+                (uproto.isObject() && gc::IsAboutToBeFinalizedUnbarriered(&protoObj)));
     }
 };
 
@@ -1356,9 +1357,10 @@ struct StackShape
     void trace(JSTracer* trc);
 };
 
-template <typename Outer>
-class StackShapeOperations {
-    const StackShape& ss() const { return static_cast<const Outer*>(this)->get(); }
+template <typename Wrapper>
+class WrappedPtrOperations<StackShape, Wrapper>
+{
+    const StackShape& ss() const { return static_cast<const Wrapper*>(this)->get(); }
 
   public:
     bool hasSlot() const { return ss().hasSlot(); }
@@ -1370,9 +1372,11 @@ class StackShapeOperations {
     uint8_t attrs() const { return ss().attrs; }
 };
 
-template <typename Outer>
-class MutableStackShapeOperations : public StackShapeOperations<Outer> {
-    StackShape& ss() { return static_cast<Outer*>(this)->get(); }
+template <typename Wrapper>
+class MutableWrappedPtrOperations<StackShape, Wrapper>
+  : public WrappedPtrOperations<StackShape, Wrapper>
+{
+    StackShape& ss() { return static_cast<Wrapper*>(this)->get(); }
 
   public:
     void updateGetterSetter(GetterOp rawGetter, SetterOp rawSetter) {
@@ -1383,19 +1387,6 @@ class MutableStackShapeOperations : public StackShapeOperations<Outer> {
     void setAttrs(uint8_t attrs) { ss().attrs = attrs; }
 };
 
-template <>
-class RootedBase<StackShape> : public MutableStackShapeOperations<JS::Rooted<StackShape>>
-{};
-
-template <>
-class HandleBase<StackShape> : public StackShapeOperations<JS::Handle<StackShape>>
-{};
-
-template <>
-class MutableHandleBase<StackShape>
-  : public MutableStackShapeOperations<JS::MutableHandle<StackShape>>
-{};
-
 inline
 Shape::Shape(const StackShape& other, uint32_t nfixed)
   : base_(other.base),
diff --git a/js/src/vm/TaggedProto.h b/js/src/vm/TaggedProto.h
index de3e86a7f5..5b9fe5c7e8 100644
--- a/js/src/vm/TaggedProto.h
+++ b/js/src/vm/TaggedProto.h
@@ -77,11 +77,11 @@ struct InternalBarrierMethods<TaggedProto>
     }
 };
 
-template<class Outer>
-class TaggedProtoOperations
+template <class Wrapper>
+class WrappedPtrOperations<TaggedProto, Wrapper>
 {
     const TaggedProto& value() const {
-        return static_cast<const Outer*>(this)->get();
+        return static_cast<const Wrapper*>(this)->get();
     }
 
   public:
@@ -95,18 +95,6 @@ class TaggedProtoOperations
     uint64_t uniqueId() const { return value().uniqueId(); }
 };
 
-template <>
-class HandleBase<TaggedProto> : public TaggedProtoOperations<Handle<TaggedProto>>
-{};
-
-template <>
-class RootedBase<TaggedProto> : public TaggedProtoOperations<Rooted<TaggedProto>>
-{};
-
-template <>
-class BarrieredBaseMixins<TaggedProto> : public TaggedProtoOperations<GCPtr<TaggedProto>>
-{};
-
 // If the TaggedProto is a JSObject pointer, convert to that type and call |f|
 // with the pointer. If the TaggedProto is lazy, calls F::defaultValue.
 template <typename F, typename... Args>