Switch to using the new rooted!/RootedGuard API for rooting.

28 files changed, 238 insertions, 237 deletions

diff --git a/components/script/devtools.rs b/components/script/devtools.rs
index 7533b159771..20394bf367a 100644
--- a/components/script/devtools.rs
+++ b/components/script/devtools.rs
@@ -22,7 +22,7 @@ use dom::element::Element;
 use dom::node::Node;
 use dom::window::Window;
 use ipc_channel::ipc::IpcSender;
-use js::jsapi::{JSAutoCompartment, ObjectClassName, RootedObject, RootedValue};
+use js::jsapi::{JSAutoCompartment, ObjectClassName};
 use js::jsval::UndefinedValue;
 use msg::constellation_msg::PipelineId;
 use script_thread::get_browsing_context;
@@ -38,24 +38,24 @@ pub fn handle_evaluate_js(global: &GlobalRef, eval: String, reply: IpcSender<Eva
         let cx = global.get_cx();
         let globalhandle = global.reflector().get_jsobject();
         let _ac = JSAutoCompartment::new(cx, globalhandle.get());
-        let mut rval = RootedValue::new(cx, UndefinedValue());
+        rooted!(in(cx) let mut rval = UndefinedValue());
         global.evaluate_js_on_global_with_result(&eval, rval.handle_mut());
 
-        if rval.ptr.is_undefined() {
+        if rval.is_undefined() {
             EvaluateJSReply::VoidValue
-        } else if rval.ptr.is_boolean() {
-            EvaluateJSReply::BooleanValue(rval.ptr.to_boolean())
-        } else if rval.ptr.is_double() || rval.ptr.is_int32() {
+        } else if rval.is_boolean() {
+            EvaluateJSReply::BooleanValue(rval.to_boolean())
+        } else if rval.is_double() || rval.is_int32() {
             EvaluateJSReply::NumberValue(FromJSValConvertible::from_jsval(cx, rval.handle(), ())
                                              .unwrap())
-        } else if rval.ptr.is_string() {
-            EvaluateJSReply::StringValue(String::from(jsstring_to_str(cx, rval.ptr.to_string())))
-        } else if rval.ptr.is_null() {
+        } else if rval.is_string() {
+            EvaluateJSReply::StringValue(String::from(jsstring_to_str(cx, rval.to_string())))
+        } else if rval.is_null() {
             EvaluateJSReply::NullValue
         } else {
-            assert!(rval.ptr.is_object());
+            assert!(rval.is_object());
 
-            let obj = RootedObject::new(cx, rval.ptr.to_object());
+            rooted!(in(cx) let obj = rval.to_object());
             let class_name = CStr::from_ptr(ObjectClassName(cx, obj.handle()));
             let class_name = str::from_utf8(class_name.to_bytes()).unwrap();
 
diff --git a/components/script/dom/bindings/callback.rs b/components/script/dom/bindings/callback.rs
index c9424adf5b2..cc1266d27ab 100644
--- a/components/script/dom/bindings/callback.rs
+++ b/components/script/dom/bindings/callback.rs
@@ -9,14 +9,14 @@ use dom::bindings::global::global_root_from_object;
 use dom::bindings::reflector::Reflectable;
 use js::jsapi::GetGlobalForObjectCrossCompartment;
 use js::jsapi::JSAutoCompartment;
-use js::jsapi::{Heap, MutableHandleObject, RootedObject, RootedValue};
+use js::jsapi::{Heap, MutableHandleObject, RootedObject};
 use js::jsapi::{IsCallable, JSContext, JSObject, JS_WrapObject};
 use js::jsapi::{JSCompartment, JS_EnterCompartment, JS_LeaveCompartment};
 use js::jsapi::{JS_GetProperty, JS_IsExceptionPending, JS_ReportPendingException};
 use js::jsval::{JSVal, UndefinedValue};
+use js::rust::RootedGuard;
 use std::default::Default;
 use std::ffi::CString;
-use std::intrinsics::return_address;
 use std::ptr;
 use std::rc::Rc;
 
@@ -114,20 +114,20 @@ impl CallbackInterface {
     /// Returns the property with the given `name`, if it is a callable object,
     /// or an error otherwise.
     pub fn get_callable_property(&self, cx: *mut JSContext, name: &str) -> Fallible<JSVal> {
-        let mut callable = RootedValue::new(cx, UndefinedValue());
-        let obj = RootedObject::new(cx, self.callback());
+        rooted!(in(cx) let mut callable = UndefinedValue());
+        rooted!(in(cx) let obj = self.callback());
         unsafe {
             let c_name = CString::new(name).unwrap();
             if !JS_GetProperty(cx, obj.handle(), c_name.as_ptr(), callable.handle_mut()) {
                 return Err(Error::JSFailed);
             }
 
-            if !callable.ptr.is_object() || !IsCallable(callable.ptr.to_object()) {
+            if !callable.is_object() || !IsCallable(callable.to_object()) {
                 return Err(Error::Type(format!("The value of the {} property is not callable",
                                                name)));
             }
         }
-        Ok(callable.ptr)
+        Ok(callable.get())
     }
 }
 
@@ -147,11 +147,9 @@ pub fn wrap_call_this_object<T: Reflectable>(cx: *mut JSContext,
 
 /// A class that performs whatever setup we need to safely make a call while
 /// this class is on the stack. After `new` returns, the call is safe to make.
-pub struct CallSetup {
+pub struct CallSetup<'a> {
     /// The compartment for reporting exceptions.
-    /// As a RootedObject, this must be the first field in order to
-    /// determine the final address on the stack correctly.
-    exception_compartment: RootedObject,
+    exception_compartment: RootedGuard<'a, *mut JSObject>,
     /// The `JSContext` used for the call.
     cx: *mut JSContext,
     /// The compartment we were in before the call.
@@ -160,20 +158,21 @@ pub struct CallSetup {
     handling: ExceptionHandling,
 }
 
-impl CallSetup {
+impl<'a> CallSetup<'a> {
     /// Performs the setup needed to make a call.
     #[allow(unrooted_must_root)]
-    pub fn new<T: CallbackContainer>(callback: &T, handling: ExceptionHandling) -> CallSetup {
+    pub fn new<T: CallbackContainer>(exception_compartment: &'a mut RootedObject,
+                                     callback: &T,
+                                     handling: ExceptionHandling)
+                                     -> CallSetup<'a> {
         let global = unsafe { global_root_from_object(callback.callback()) };
         let cx = global.r().get_cx();
 
-        let exception_compartment = unsafe {
+        exception_compartment.ptr = unsafe {
             GetGlobalForObjectCrossCompartment(callback.callback())
         };
         CallSetup {
-            exception_compartment: RootedObject::new_with_addr(cx,
-                                                               exception_compartment,
-                                                               unsafe { return_address() }),
+            exception_compartment: RootedGuard::new(cx, exception_compartment),
             cx: cx,
             old_compartment: unsafe { JS_EnterCompartment(cx, callback.callback()) },
             handling: handling,
@@ -186,7 +185,7 @@ impl CallSetup {
     }
 }
 
-impl Drop for CallSetup {
+impl<'a> Drop for CallSetup<'a> {
     fn drop(&mut self) {
         unsafe {
             JS_LeaveCompartment(self.cx, self.old_compartment);
@@ -195,7 +194,7 @@ impl Drop for CallSetup {
                                           unsafe { JS_IsExceptionPending(self.cx) };
         if need_to_deal_with_exception {
             unsafe {
-                let _ac = JSAutoCompartment::new(self.cx, self.exception_compartment.ptr);
+                let _ac = JSAutoCompartment::new(self.cx, *self.exception_compartment);
                 JS_ReportPendingException(self.cx);
             }
         }
diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 76aab6b9b53..ef50ebeb71d 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -2278,34 +2278,33 @@ def CreateBindingJSObject(descriptor, parent=None):
         assert not descriptor.isGlobal()
         create += """
 let handler = RegisterBindings::proxy_handlers[PrototypeList::Proxies::%s as usize];
-let private = RootedValue::new(cx, PrivateValue(raw as *const libc::c_void));
+rooted!(in(cx) let private = PrivateValue(raw as *const libc::c_void));
 let obj = NewProxyObject(cx, handler,
                          private.handle(),
-                         proto.ptr, %s.get(),
+                         proto.get(), %s.get(),
                          ptr::null_mut(), ptr::null_mut());
 assert!(!obj.is_null());
-let obj = RootedObject::new(cx, obj);\
+rooted!(in(cx) let obj = obj);\
 """ % (descriptor.name, parent)
     elif descriptor.isGlobal():
-        create += ("let obj = RootedObject::new(\n"
-                   "    cx,\n"
+        create += ("rooted!(in(cx) let obj =\n"
                    "    create_dom_global(\n"
                    "        cx,\n"
                    "        &Class.base as *const js::jsapi::Class as *const JSClass,\n"
                    "        raw as *const libc::c_void,\n"
                    "        Some(%s))\n"
                    ");\n"
-                   "assert!(!obj.ptr.is_null());" % TRACE_HOOK_NAME)
+                   "assert!(!obj.is_null());" % TRACE_HOOK_NAME)
     else:
-        create += ("let obj = RootedObject::new(cx, JS_NewObjectWithGivenProto(\n"
+        create += ("rooted!(in(cx) let obj = JS_NewObjectWithGivenProto(\n"
                    "    cx, &Class.base as *const js::jsapi::Class as *const JSClass, proto.handle()));\n"
-                   "assert!(!obj.ptr.is_null());\n"
+                   "assert!(!obj.is_null());\n"
                    "\n"
-                   "JS_SetReservedSlot(obj.ptr, DOM_OBJECT_SLOT,\n"
+                   "JS_SetReservedSlot(obj.get(), DOM_OBJECT_SLOT,\n"
                    "                   PrivateValue(raw as *const libc::c_void));")
     if descriptor.weakReferenceable:
         create += """
-JS_SetReservedSlot(obj.ptr, DOM_WEAK_SLOT, PrivateValue(ptr::null()));"""
+JS_SetReservedSlot(obj.get(), DOM_WEAK_SLOT, PrivateValue(ptr::null()));"""
     return create
 
 
@@ -2344,7 +2343,7 @@ def CopyUnforgeablePropertiesToInstance(descriptor):
     # reflector, so we can make sure we don't get confused by named getters.
     if descriptor.proxy:
         copyCode += """\
-let expando = RootedObject::new(cx, ensure_expando_object(cx, obj.handle()));
+rooted!(in(cx) let expando = ensure_expando_object(cx, obj.handle()));
 """
         obj = "expando"
     else:
@@ -2358,9 +2357,9 @@ let expando = RootedObject::new(cx, ensure_expando_object(cx, obj.handle()));
     else:
         copyFunc = "JS_InitializePropertiesFromCompatibleNativeObject"
     copyCode += """\
-let mut unforgeable_holder = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut unforgeable_holder = ptr::null_mut());
 unforgeable_holder.handle_mut().set(
-    JS_GetReservedSlot(proto.ptr, DOM_PROTO_UNFORGEABLE_HOLDER_SLOT).to_object());
+    JS_GetReservedSlot(proto.get(), DOM_PROTO_UNFORGEABLE_HOLDER_SLOT).to_object());
 assert!(%(copyFunc)s(cx, %(obj)s.handle(), unforgeable_holder.handle()));
 """ % {'copyFunc': copyFunc, 'obj': obj}
 
@@ -2393,25 +2392,25 @@ let scope = scope.reflector().get_jsobject();
 assert!(!scope.get().is_null());
 assert!(((*JS_GetClass(scope.get())).flags & JSCLASS_IS_GLOBAL) != 0);
 
-let mut proto = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut proto = ptr::null_mut());
 let _ac = JSAutoCompartment::new(cx, scope.get());
 GetProtoObject(cx, scope, proto.handle_mut());
-assert!(!proto.ptr.is_null());
+assert!(!proto.is_null());
 
 %(createObject)s
 
 %(copyUnforgeable)s
-(*raw).init_reflector(obj.ptr);
+(*raw).init_reflector(obj.get());
 
 Root::from_ref(&*raw)""" % {'copyUnforgeable': unforgeable, 'createObject': create})
         else:
             create = CreateBindingJSObject(self.descriptor)
             return CGGeneric("""\
 %(createObject)s
-(*raw).init_reflector(obj.ptr);
+(*raw).init_reflector(obj.get());
 
-let _ac = JSAutoCompartment::new(cx, obj.ptr);
-let mut proto = RootedObject::new(cx, ptr::null_mut());
+let _ac = JSAutoCompartment::new(cx, obj.get());
+rooted!(in(cx) let mut proto = ptr::null_mut());
 GetProtoObject(cx, obj.handle(), proto.handle_mut());
 JS_SetPrototype(cx, obj.handle(), proto.handle());
 
@@ -2525,29 +2524,29 @@ class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
         if self.descriptor.interface.isCallback():
             assert not self.descriptor.interface.ctor() and self.descriptor.interface.hasConstants()
             return CGGeneric("""\
-let mut interface = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut interface = ptr::null_mut());
 create_callback_interface_object(cx, global, sConstants, %(name)s, interface.handle_mut());
-assert!(!interface.ptr.is_null());
+assert!(!interface.is_null());
 assert!((*cache)[PrototypeList::Constructor::%(id)s as usize].is_null());
-(*cache)[PrototypeList::Constructor::%(id)s as usize] = interface.ptr;
+(*cache)[PrototypeList::Constructor::%(id)s as usize] = interface.get();
 <*mut JSObject>::post_barrier((*cache).as_mut_ptr().offset(PrototypeList::Constructor::%(id)s as isize),
                               ptr::null_mut(),
-                              interface.ptr);
+                              interface.get());
 """ % {"id": name, "name": str_to_const_array(name)})
 
         if len(self.descriptor.prototypeChain) == 1:
             if self.descriptor.interface.getExtendedAttribute("ExceptionClass"):
-                getPrototypeProto = "prototype_proto.ptr = JS_GetErrorPrototype(cx)"
+                getPrototypeProto = "prototype_proto.set(JS_GetErrorPrototype(cx))"
             else:
-                getPrototypeProto = "prototype_proto.ptr = JS_GetObjectPrototype(cx, global)"
+                getPrototypeProto = "prototype_proto.set(JS_GetObjectPrototype(cx, global))"
         else:
             getPrototypeProto = ("%s::GetProtoObject(cx, global, prototype_proto.handle_mut())" %
                                  toBindingNamespace(self.descriptor.prototypeChain[-2]))
 
         code = [CGGeneric("""\
-let mut prototype_proto = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut prototype_proto = ptr::null_mut());
 %s;
-assert!(!prototype_proto.ptr.is_null());""" % getPrototypeProto)]
+assert!(!prototype_proto.is_null());""" % getPrototypeProto)]
 
         properties = {
             "id": name,
@@ -2561,7 +2560,7 @@ assert!(!prototype_proto.ptr.is_null());""" % getPrototypeProto)]
                 properties[arrayName] = "&[]"
 
         code.append(CGGeneric("""
-let mut prototype = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut prototype = ptr::null_mut());
 create_interface_prototype_object(cx,
                                   prototype_proto.handle(),
                                   &PrototypeClass,
@@ -2570,12 +2569,12 @@ create_interface_prototype_object(cx,
                                   %(consts)s,
                                   %(unscopables)s,
                                   prototype.handle_mut());
-assert!(!prototype.ptr.is_null());
+assert!(!prototype.is_null());
 assert!((*cache)[PrototypeList::ID::%(id)s as usize].is_null());
-(*cache)[PrototypeList::ID::%(id)s as usize] = prototype.ptr;
+(*cache)[PrototypeList::ID::%(id)s as usize] = prototype.get();
 <*mut JSObject>::post_barrier((*cache).as_mut_ptr().offset(PrototypeList::ID::%(id)s as isize),
                               ptr::null_mut(),
-                              prototype.ptr);
+                              prototype.get());
 """ % properties))
 
         if self.descriptor.interface.hasInterfaceObject():
@@ -2587,15 +2586,15 @@ assert!((*cache)[PrototypeList::ID::%(id)s as usize].is_null());
             if self.descriptor.interface.parent:
                 parentName = toBindingNamespace(self.descriptor.getParentName())
                 code.append(CGGeneric("""
-let mut interface_proto = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut interface_proto = ptr::null_mut());
 %s::GetConstructorObject(cx, global, interface_proto.handle_mut());""" % parentName))
             else:
                 code.append(CGGeneric("""
-let interface_proto = RootedObject::new(cx, JS_GetFunctionPrototype(cx, global));"""))
+rooted!(in(cx) let interface_proto = JS_GetFunctionPrototype(cx, global));"""))
             code.append(CGGeneric("""\
-assert!(!interface_proto.ptr.is_null());
+assert!(!interface_proto.is_null());
 
-let mut interface = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut interface = ptr::null_mut());
 create_noncallback_interface_object(cx,
                                     global,
                                     interface_proto.handle(),
@@ -2607,14 +2606,14 @@ create_noncallback_interface_object(cx,
                                     %(name)s,
                                     %(length)s,
                                     interface.handle_mut());
-assert!(!interface.ptr.is_null());""" % properties))
+assert!(!interface.is_null());""" % properties))
             if self.descriptor.hasDescendants():
                 code.append(CGGeneric("""\
 assert!((*cache)[PrototypeList::Constructor::%(id)s as usize].is_null());
-(*cache)[PrototypeList::Constructor::%(id)s as usize] = interface.ptr;
+(*cache)[PrototypeList::Constructor::%(id)s as usize] = interface.get();
 <*mut JSObject>::post_barrier((*cache).as_mut_ptr().offset(PrototypeList::Constructor::%(id)s as isize),
                               ptr::null_mut(),
-                              interface.ptr);
+                              interface.get());
 """ % properties))
 
         constructors = self.descriptor.interface.namedConstructors
@@ -2649,15 +2648,15 @@ assert!((*cache)[PrototypeList::Constructor::%(id)s as usize].is_null());
                 holderClass = "&Class.base as *const js::jsapi::Class as *const JSClass"
                 holderProto = "prototype.handle()"
             code.append(CGGeneric("""
-let mut unforgeable_holder = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut unforgeable_holder = ptr::null_mut());
 unforgeable_holder.handle_mut().set(
     JS_NewObjectWithoutMetadata(cx, %(holderClass)s, %(holderProto)s));
-assert!(!unforgeable_holder.ptr.is_null());
+assert!(!unforgeable_holder.is_null());
 """ % {'holderClass': holderClass, 'holderProto': holderProto}))
             code.append(InitUnforgeablePropertiesOnHolder(self.descriptor, self.properties))
             code.append(CGGeneric("""\
-JS_SetReservedSlot(prototype.ptr, DOM_PROTO_UNFORGEABLE_HOLDER_SLOT,
-                   ObjectValue(&*unforgeable_holder.ptr))"""))
+JS_SetReservedSlot(prototype.get(), DOM_PROTO_UNFORGEABLE_HOLDER_SLOT,
+                   ObjectValue(&*unforgeable_holder.get()))"""))
 
         return CGList(code, "\n")
 
@@ -2826,9 +2825,9 @@ class CGDefineDOMInterfaceMethod(CGAbstractMethod):
         return CGGeneric("""\
 assert!(!global.get().is_null());
 %s
-let mut proto = RootedObject::new(cx, ptr::null_mut());
+rooted!(in(cx) let mut proto = ptr::null_mut());
 %s(cx, global, proto.handle_mut());
-assert!(!proto.ptr.is_null());""" % (getCheck(self.descriptor), function))
+assert!(!proto.is_null());""" % (getCheck(self.descriptor), function))
 
 
 def needCx(returnType, arguments, considerTypes):
@@ -3277,15 +3276,15 @@ class CGSpecializedForwardingSetter(CGSpecializedSetter):
         assert all(ord(c) < 128 for c in attrName)
         assert all(ord(c) < 128 for c in forwardToAttrName)
         return CGGeneric("""\
-let mut v = RootedValue::new(cx, UndefinedValue());
+rooted!(in(cx) let mut v = UndefinedValue());
 if !JS_GetProperty(cx, obj, %s as *const u8 as *const libc::c_char, v.handle_mut()) {
     return false;
 }
-if !v.ptr.is_object() {
+if !v.is_object() {
     throw_type_error(cx, "Value.%s is not an object.");
     return false;
 }
-let target_obj = RootedObject::new(cx, v.ptr.to_object());
+rooted!(in(cx) let target_obj = v.to_object());
 JS_SetProperty(cx, target_obj.handle(), %s as *const u8 as *const libc::c_char, args.get(0))
 """ % (str_to_const_array(attrName), attrName, str_to_const_array(forwardToAttrName)))
 
@@ -4342,7 +4341,7 @@ class CGProxySpecialOperation(CGPerSignatureCall):
             }
             self.cgRoot.prepend(instantiateJSToNativeConversionTemplate(
                 template, templateValues, declType, argument.identifier.name))
-            self.cgRoot.prepend(CGGeneric("let value = RootedValue::new(cx, desc.get().value);"))
+            self.cgRoot.prepend(CGGeneric("rooted!(in(cx) let value = desc.value);"))
         elif operation.isGetter():
             self.cgRoot.prepend(CGGeneric("let mut found = false;"))
 
@@ -4450,7 +4449,7 @@ class CGProxyUnwrap(CGAbstractMethod):
     obj = js::UnwrapObject(obj);
 }*/
 //MOZ_ASSERT(IsProxy(obj));
-let box_ = GetProxyPrivate(*obj.ptr).to_private() as *const %s;
+let box_ = GetProxyPrivate(obj.get()).to_private() as *const %s;
 return box_;""" % self.descriptor.concreteType)
 
 
@@ -4458,7 +4457,7 @@ class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
     def __init__(self, descriptor):
         args = [Argument('*mut JSContext', 'cx'), Argument('HandleObject', 'proxy'),
                 Argument('HandleId', 'id'),
-                Argument('MutableHandle<PropertyDescriptor>', 'desc')]
+                Argument('MutableHandle<PropertyDescriptor>', 'desc', mutable=True)]
         CGAbstractExternMethod.__init__(self, descriptor, "getOwnPropertyDescriptor",
                                         "bool", args)
         self.descriptor = descriptor
@@ -4475,13 +4474,14 @@ class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
             attrs = "JSPROP_ENUMERATE"
             if self.descriptor.operations['IndexedSetter'] is None:
                 attrs += " | JSPROP_READONLY"
-            fillDescriptor = ("desc.get().value = result_root.ptr;\n"
-                              "fill_property_descriptor(&mut *desc.ptr, *proxy.ptr, %s);\n"
+            # FIXME(#11868) Should assign to desc.value, desc.get() is a copy.
+            fillDescriptor = ("desc.get().value = result_root.get();\n"
+                              "fill_property_descriptor(&mut desc, proxy.get(), %s);\n"
                               "return true;" % attrs)
             templateValues = {
                 'jsvalRef': 'result_root.handle_mut()',
                 'successCode': fillDescriptor,
-                'pre': 'let mut result_root = RootedValue::new(cx, UndefinedValue());'
+                'pre': 'rooted!(in(cx) let mut result_root = UndefinedValue());'
             }
             get += ("if let Some(index) = index {\n" +
                     "    let this = UnwrapProxy(proxy);\n" +
@@ -4500,13 +4500,14 @@ class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
                 attrs = " | ".join(attrs)
             else:
                 attrs = "0"
-            fillDescriptor = ("desc.get().value = result_root.ptr;\n"
-                              "fill_property_descriptor(&mut *desc.ptr, *proxy.ptr, %s);\n"
+            # FIXME(#11868) Should assign to desc.value, desc.get() is a copy.
+            fillDescriptor = ("desc.get().value = result_root.get();\n"
+                              "fill_property_descriptor(&mut desc, proxy.get(), %s);\n"
                               "return true;" % attrs)
             templateValues = {
                 'jsvalRef': 'result_root.handle_mut()',
                 'successCode': fillDescriptor,
-                'pre': 'let mut result_root = RootedValue::new(cx, UndefinedValue());'
+                'pre': 'rooted!(in(cx) let mut result_root = UndefinedValue());'
             }
             # Once we start supporting OverrideBuiltins we need to make
             # ResolveOwnProperty or EnumerateOwnProperties filter out named
@@ -4518,16 +4519,17 @@ class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
         else:
             namedGet = ""
 
+        # FIXME(#11868) Should assign to desc.obj, desc.get() is a copy.
         return get + """\
-let expando = RootedObject::new(cx, get_expando_object(proxy));
+rooted!(in(cx) let expando = get_expando_object(proxy));
 //if (!xpc::WrapperFactory::IsXrayWrapper(proxy) && (expando = GetExpandoObject(proxy))) {
-if !expando.ptr.is_null() {
+if !expando.is_null() {
     if !JS_GetPropertyDescriptorById(cx, expando.handle(), id, desc) {
         return false;
     }
-    if !desc.get().obj.is_null() {
+    if !desc.obj.is_null() {
         // Pretend the property lives on the wrapper.
-        desc.get().obj = *proxy.ptr;
+        desc.get().obj = proxy.get();
         return true;
     }
 }
@@ -4637,7 +4639,7 @@ class CGDOMJSProxyHandler_ownPropertyKeys(CGAbstractExternMethod):
             body += dedent(
                 """
                 for i in 0..(*unwrapped_proxy).Length() {
-                    let rooted_jsid = RootedId::new(cx, int_to_jsid(i as i32));
+                    rooted!(in(cx) let rooted_jsid = int_to_jsid(i as i32));
                     AppendToAutoIdVector(props, rooted_jsid.handle().get());
                 }
                 """)
@@ -4648,9 +4650,9 @@ class CGDOMJSProxyHandler_ownPropertyKeys(CGAbstractExternMethod):
                 for name in (*unwrapped_proxy).SupportedPropertyNames() {
                     let cstring = CString::new(name).unwrap();
                     let jsstring = JS_AtomizeAndPinString(cx, cstring.as_ptr());
-                    let rooted = RootedString::new(cx, jsstring);
+                    rooted!(in(cx) let rooted = jsstring);
                     let jsid = INTERNED_STRING_TO_JSID(cx, rooted.handle().get());
-                    let rooted_jsid = RootedId::new(cx, jsid);
+                    rooted!(in(cx) let rooted_jsid = jsid);
                     AppendToAutoIdVector(props, rooted_jsid.handle().get());
                 }
                 """)
@@ -4659,7 +4661,7 @@ class CGDOMJSProxyHandler_ownPropertyKeys(CGAbstractExternMethod):
             """
             let expando = get_expando_object(proxy);
             if !expando.is_null() {
-                let rooted_expando = RootedObject::new(cx, expando);
+                rooted!(in(cx) let rooted_expando = expando);
                 GetPropertyKeys(cx, rooted_expando.handle(), JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS, props);
             }
 
@@ -4693,7 +4695,7 @@ class CGDOMJSProxyHandler_getOwnEnumerablePropertyKeys(CGAbstractExternMethod):
             body += dedent(
                 """
                 for i in 0..(*unwrapped_proxy).Length() {
-                    let rooted_jsid = RootedId::new(cx, int_to_jsid(i as i32));
+                    rooted!(in(cx) let rooted_jsid = int_to_jsid(i as i32));
                     AppendToAutoIdVector(props, rooted_jsid.handle().get());
                 }
                 """)
@@ -4702,7 +4704,7 @@ class CGDOMJSProxyHandler_getOwnEnumerablePropertyKeys(CGAbstractExternMethod):
             """
             let expando = get_expando_object(proxy);
             if !expando.is_null() {
-                let rooted_expando = RootedObject::new(cx, expando);
+                rooted!(in(cx) let rooted_expando = expando);
                 GetPropertyKeys(cx, rooted_expando.handle(), JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS, props);
             }
 
@@ -4748,8 +4750,8 @@ class CGDOMJSProxyHandler_hasOwn(CGAbstractExternMethod):
             named = ""
 
         return indexed + """\
-let expando = RootedObject::new(cx, get_expando_object(proxy));
-if !expando.ptr.is_null() {
+rooted!(in(cx) let expando = get_expando_object(proxy));
+if !expando.is_null() {
     let ok = JS_HasPropertyById(cx, expando.handle(), id, bp);
     if !ok || *bp {
         return ok;
@@ -4773,8 +4775,8 @@ class CGDOMJSProxyHandler_get(CGAbstractExternMethod):
 
     def getBody(self):
         getFromExpando = """\
-let expando = RootedObject::new(cx, get_expando_object(proxy));
-if !expando.ptr.is_null() {
+rooted!(in(cx) let expando = get_expando_object(proxy));
+if !expando.is_null() {
     let mut hasProp = false;
     if !JS_HasPropertyById(cx, expando.handle(), id, &mut hasProp) {
         return false;
@@ -4829,7 +4831,7 @@ if found {
     return true;
 }
 %s
-*vp.ptr = UndefinedValue();
+vp.set(UndefinedValue());
 return true;""" % (getIndexedOrExpando, getNamed)
 
     def definition_body(self):
@@ -5297,7 +5299,7 @@ class CGDictionary(CGThing):
             return CGGeneric("%s: %s,\n" % (name, conversion.define()))
 
         def varInsert(varName, dictionaryName):
-            insertion = ("let mut %s_js = RootedValue::new(cx, UndefinedValue());\n"
+            insertion = ("rooted!(in(cx) let mut %s_js = UndefinedValue());\n"
                          "%s.to_jsval(cx, %s_js.handle_mut());\n"
                          "set_dictionary_property(cx, obj.handle(), \"%s\", %s_js.handle()).unwrap();"
                          % (varName, varName, varName, dictionaryName, varName))
@@ -5324,13 +5326,14 @@ class CGDictionary(CGThing):
             "    }\n"
             "    pub unsafe fn new(cx: *mut JSContext, val: HandleValue) -> Result<${selfName}, ()> {\n"
             "        let object = if val.get().is_null_or_undefined() {\n"
-            "            RootedObject::new(cx, ptr::null_mut())\n"
+            "            ptr::null_mut()\n"
             "        } else if val.get().is_object() {\n"
-            "            RootedObject::new(cx, val.get().to_object())\n"
+            "            val.get().to_object()\n"
             "        } else {\n"
             "            throw_type_error(cx, \"Value not an object.\");\n"
             "            return Err(());\n"
             "        };\n"
+            "        rooted!(in(cx) let object = object);\n"
             "        Ok(${selfName} {\n"
             "${initParent}"
             "${initMembers}"
@@ -5348,9 +5351,9 @@ class CGDictionary(CGThing):
             "\n"
             "impl ToJSValConvertible for ${selfName} {\n"
             "    unsafe fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {\n"
-            "        let obj = RootedObject::new(cx, JS_NewObject(cx, ptr::null()));\n"
+            "        rooted!(in(cx) let obj = JS_NewObject(cx, ptr::null()));\n"
             "${insertMembers}"
-            "        rval.set(ObjectOrNullValue(obj.ptr))\n"
+            "        rval.set(ObjectOrNullValue(obj.get()))\n"
             "    }\n"
             "}\n").substitute({
                 "selfName": self.makeClassName(d),
@@ -5400,7 +5403,7 @@ class CGDictionary(CGThing):
 
         conversion = (
             "{\n"
-            "let mut rval = RootedValue::new(cx, UndefinedValue());\n"
+            "rooted!(in(cx) let mut rval = UndefinedValue());\n"
             "match try!(get_dictionary_property(cx, object.handle(), \"%s\", rval.handle_mut())) {\n"
             "    true => {\n"
             "%s\n"
@@ -5548,8 +5551,8 @@ class CGBindingRoot(CGThing):
             'js::jsapi::{JSNative, JSObject, JSNativeWrapper, JSPropertySpec}',
             'js::jsapi::{JSString, JSTracer, JSType, JSTypedMethodJitInfo, JSValueType}',
             'js::jsapi::{ObjectOpResult, JSJitInfo_OpType, MutableHandle, MutableHandleObject}',
-            'js::jsapi::{MutableHandleValue, PropertyDescriptor, RootedId, RootedObject}',
-            'js::jsapi::{RootedString, RootedValue, SymbolCode, jsid}',
+            'js::jsapi::{MutableHandleValue, PropertyDescriptor, RootedObject}',
+            'js::jsapi::{SymbolCode, jsid}',
             'js::jsval::JSVal',
             'js::jsval::{ObjectValue, ObjectOrNullValue, PrivateValue}',
             'js::jsval::{NullValue, UndefinedValue}',
@@ -5769,16 +5772,17 @@ class CGCallback(CGClass):
         args.insert(0, Argument(None, "&self"))
         argsWithoutThis.insert(0, Argument(None, "&self"))
 
-        setupCall = ("let s = CallSetup::new(self, aExceptionHandling);\n"
+        setupCall = ("let mut s_ec = RootedObject::new_unrooted(ptr::null_mut());\n"
+                     "let s = CallSetup::new(&mut s_ec, self, aExceptionHandling);\n"
                      "if s.get_context().is_null() {\n"
                      "    return Err(JSFailed);\n"
                      "}\n")
 
         bodyWithThis = string.Template(
             setupCall +
-            "let mut thisObjJS = RootedObject::new(s.get_context(), ptr::null_mut());\n"
+            "rooted!(in(s.get_context()) let mut thisObjJS = ptr::null_mut());\n"
             "wrap_call_this_object(s.get_context(), thisObj, thisObjJS.handle_mut());\n"
-            "if thisObjJS.ptr.is_null() {\n"
+            "if thisObjJS.is_null() {\n"
             "    return Err(JSFailed);\n"
             "}\n"
             "return ${methodName}(${callArgs});").substitute({
@@ -5787,7 +5791,7 @@ class CGCallback(CGClass):
             })
         bodyWithoutThis = string.Template(
             setupCall +
-            "let thisObjJS = RootedObject::new(s.get_context(), ptr::null_mut());"
+            "rooted!(in(s.get_context()) let thisObjJS = ptr::null_mut());"
             "return ${methodName}(${callArgs});").substitute({
                 "callArgs": ", ".join(argnamesWithoutThis),
                 "methodName": 'self.' + method.name,
@@ -6006,8 +6010,8 @@ class CallbackMember(CGNativeMember):
 
         conversion = wrapForType(
             "argv_root.handle_mut()", result=argval,
-            successCode="argv[%s] = argv_root.ptr;" % jsvalIndex,
-            pre="let mut argv_root = RootedValue::new(cx, UndefinedValue());")
+            successCode="argv[%s] = argv_root.get();" % jsvalIndex,
+            pre="rooted!(in(cx) let mut argv_root = UndefinedValue());")
         if arg.variadic:
             conversion = string.Template(
                 "for idx in 0..${arg}.len() {\n" +
@@ -6077,7 +6081,7 @@ class CallbackMethod(CallbackMember):
                                 needThisHandling)
 
     def getRvalDecl(self):
-        return "let mut rval = RootedValue::new(cx, UndefinedValue());\n"
+        return "rooted!(in(cx) let mut rval = UndefinedValue());\n"
 
     def getCall(self):
         replacements = {
@@ -6092,7 +6096,7 @@ class CallbackMethod(CallbackMember):
             replacements["argc"] = "0"
         return string.Template(
             "${getCallable}"
-            "let rootedThis = RootedObject::new(cx, ${thisObj});\n"
+            "rooted!(in(cx) let rootedThis = ${thisObj});\n"
             "let ok = JS_CallFunctionValue(\n"
             "    cx, rootedThis.handle(), callable.handle(),\n"
             "    &HandleValueArray {\n"
@@ -6116,7 +6120,7 @@ class CallCallback(CallbackMethod):
         return "aThisObj.get()"
 
     def getCallableDecl(self):
-        return "let callable = RootedValue::new(cx, ObjectValue(&*self.parent.callback()));\n"
+        return "rooted!(in(cx) let callable = ObjectValue(&*self.parent.callback()));\n"
 
 
 class CallbackOperationBase(CallbackMethod):
@@ -6141,17 +6145,17 @@ class CallbackOperationBase(CallbackMethod):
             "methodName": self.methodName
         }
         getCallableFromProp = string.Template(
-            'RootedValue::new(cx, try!(self.parent.get_callable_property(cx, "${methodName}")))'
+            'try!(self.parent.get_callable_property(cx, "${methodName}"))'
         ).substitute(replacements)
         if not self.singleOperation:
-            return 'JS::Rooted<JS::Value> callable(cx);\n' + getCallableFromProp
+            return 'rooted!(in(cx) let callable =\n' + getCallableFromProp + ');\n'
         return (
             'let isCallable = IsCallable(self.parent.callback());\n'
-            'let callable =\n' +
+            'rooted!(in(cx) let callable =\n' +
             CGIndenter(
                 CGIfElseWrapper('isCallable',
-                                CGGeneric('RootedValue::new(cx, ObjectValue(&*self.parent.callback()))'),
-                                CGGeneric(getCallableFromProp))).define() + ';\n')
+                                CGGeneric('ObjectValue(&*self.parent.callback())'),
+                                CGGeneric(getCallableFromProp))).define() + ');\n')
 
 
 class CallbackOperation(CallbackOperationBase):
diff --git a/components/script/dom/bindings/error.rs b/components/script/dom/bindings/error.rs
index ed0b81c4d64..161e477a85a 100644
--- a/components/script/dom/bindings/error.rs
+++ b/components/script/dom/bindings/error.rs
@@ -10,7 +10,7 @@ use dom::bindings::global::GlobalRef;
 use dom::domexception::{DOMErrorName, DOMException};
 use js::error::{throw_range_error, throw_type_error};
 use js::jsapi::JSAutoCompartment;
-use js::jsapi::{JSContext, JSObject, RootedValue};
+use js::jsapi::{JSContext, JSObject};
 use js::jsapi::{JS_IsExceptionPending, JS_ReportPendingException, JS_SetPendingException};
 use js::jsval::UndefinedValue;
 
@@ -115,7 +115,7 @@ pub unsafe fn throw_dom_exception(cx: *mut JSContext, global: GlobalRef, result:
 
     assert!(!JS_IsExceptionPending(cx));
     let exception = DOMException::new(global, code);
-    let mut thrown = RootedValue::new(cx, UndefinedValue());
+    rooted!(in(cx) let mut thrown = UndefinedValue());
     exception.to_jsval(cx, thrown.handle_mut());
     JS_SetPendingException(cx, thrown.handle());
 }
diff --git a/components/script/dom/bindings/interface.rs b/components/script/dom/bindings/interface.rs
index 500f262f3af..c61a3f211c4 100644
--- a/components/script/dom/bindings/interface.rs
+++ b/components/script/dom/bindings/interface.rs
@@ -19,8 +19,8 @@ use js::jsapi::{JS_DefineProperty2, JS_DefineProperty4, JS_DefinePropertyById3};
 use js::jsapi::{JS_GetClass, JS_GetFunctionObject, JS_GetPrototype, JS_LinkConstructorAndPrototype};
 use js::jsapi::{JS_NewFunction, JS_NewObject, JS_NewObjectWithUniqueType};
 use js::jsapi::{JS_NewPlainObject, JS_NewStringCopyN, MutableHandleObject};
-use js::jsapi::{MutableHandleValue, ObjectOps, RootedId, RootedObject};
-use js::jsapi::{RootedString, RootedValue, SymbolCode, TrueHandleValue, Value};
+use js::jsapi::{MutableHandleValue, ObjectOps};
+use js::jsapi::{SymbolCode, TrueHandleValue, Value};
 use js::jsval::{BooleanValue, DoubleValue, Int32Value, JSVal, NullValue, UInt32Value};
 use js::rust::{define_methods, define_properties};
 use libc;
@@ -74,7 +74,7 @@ fn define_constants(
         obj: HandleObject,
         constants: &[ConstantSpec]) {
     for spec in constants {
-        let value = RootedValue::new(cx, spec.get_value());
+        rooted!(in(cx) let value = spec.get_value());
         unsafe {
             assert!(JS_DefineProperty(cx,
                                       obj,
@@ -243,13 +243,13 @@ pub unsafe fn create_interface_prototype_object(
     create_object(cx, proto, class, regular_methods, regular_properties, constants, rval);
 
     if !unscopable_names.is_empty() {
-        let mut unscopable_obj = RootedObject::new(cx, ptr::null_mut());
+        rooted!(in(cx) let mut unscopable_obj = ptr::null_mut());
         create_unscopable_object(cx, unscopable_names, unscopable_obj.handle_mut());
 
         let unscopable_symbol = GetWellKnownSymbol(cx, SymbolCode::unscopables);
         assert!(!unscopable_symbol.is_null());
 
-        let unscopable_id = RootedId::new(cx, RUST_SYMBOL_TO_JSID(unscopable_symbol));
+        rooted!(in(cx) let unscopable_id = RUST_SYMBOL_TO_JSID(unscopable_symbol));
         assert!(JS_DefinePropertyById3(
             cx, rval.handle(), unscopable_id.handle(), unscopable_obj.handle(),
             JSPROP_READONLY, None, None))
@@ -288,7 +288,7 @@ pub unsafe fn create_named_constructors(
         global: HandleObject,
         named_constructors: &[(NonNullJSNative, &[u8], u32)],
         interface_prototype_object: HandleObject) {
-    let mut constructor = RootedObject::new(cx, ptr::null_mut());
+    rooted!(in(cx) let mut constructor = ptr::null_mut());
 
     for &(native, name, arity) in named_constructors {
         assert!(*name.last().unwrap() == b'\0');
@@ -299,8 +299,8 @@ pub unsafe fn create_named_constructors(
                                  JSFUN_CONSTRUCTOR,
                                  name.as_ptr() as *const libc::c_char);
         assert!(!fun.is_null());
-        constructor.ptr = JS_GetFunctionObject(fun);
-        assert!(!constructor.ptr.is_null());
+        constructor.set(JS_GetFunctionObject(fun));
+        assert!(!constructor.is_null());
 
         assert!(JS_DefineProperty1(cx,
                                    constructor.handle(),
@@ -339,12 +339,13 @@ unsafe fn has_instance(
         // Step 1.
         return Ok(false);
     }
-    let mut value = RootedObject::new(cx, value.to_object());
+    rooted!(in(cx) let mut value = value.to_object());
 
     let js_class = JS_GetClass(interface_object.get());
     let object_class = &*(js_class as *const NonCallbackInterfaceObjectClass);
 
-    if let Ok(dom_class) = get_dom_class(UncheckedUnwrapObject(value.ptr, /* stopAtWindowProxy = */ 0)) {
+    if let Ok(dom_class) = get_dom_class(UncheckedUnwrapObject(value.get(),
+                                                               /* stopAtWindowProxy = */ 0)) {
         if dom_class.interface_chain[object_class.proto_depth as usize] == object_class.proto_id {
             // Step 4.
             return Ok(true);
@@ -355,15 +356,15 @@ unsafe fn has_instance(
     let global = GetGlobalForObjectCrossCompartment(interface_object.get());
     assert!(!global.is_null());
     let proto_or_iface_array = get_proto_or_iface_array(global);
-    let prototype = RootedObject::new(cx, (*proto_or_iface_array)[object_class.proto_id as usize]);
-    assert!(!prototype.ptr.is_null());
+    rooted!(in(cx) let prototype = (*proto_or_iface_array)[object_class.proto_id as usize]);
+    assert!(!prototype.is_null());
     // Step 3 only concern legacy callback interface objects (i.e. NodeFilter).
 
     while JS_GetPrototype(cx, value.handle(), value.handle_mut()) {
-        if value.ptr.is_null() {
+        if value.is_null() {
             // Step 5.2.
             return Ok(false);
-        } else if value.ptr as *const _ == prototype.ptr {
+        } else if value.get() as *const _ == prototype.get() {
             // Step 5.3.
             return Ok(true);
         }
@@ -433,9 +434,8 @@ pub unsafe fn define_guarded_properties(
 
 unsafe fn define_name(cx: *mut JSContext, obj: HandleObject, name: &[u8]) {
     assert!(*name.last().unwrap() == b'\0');
-    let name = RootedString::new(
-        cx, JS_AtomizeAndPinString(cx, name.as_ptr() as *const libc::c_char));
-    assert!(!name.ptr.is_null());
+    rooted!(in(cx) let name = JS_AtomizeAndPinString(cx, name.as_ptr() as *const libc::c_char));
+    assert!(!name.is_null());
     assert!(JS_DefineProperty2(cx,
                                obj,
                                b"name\0".as_ptr() as *const libc::c_char,
diff --git a/components/script/dom/bindings/proxyhandler.rs b/components/script/dom/bindings/proxyhandler.rs
index f7505b77fc7..9db30d8835c 100644
--- a/components/script/dom/bindings/proxyhandler.rs
+++ b/components/script/dom/bindings/proxyhandler.rs
@@ -13,7 +13,7 @@ use js::glue::InvokeGetOwnPropertyDescriptor;
 use js::glue::{GetProxyHandler, SetProxyExtra};
 use js::jsapi::GetObjectProto;
 use js::jsapi::JS_GetPropertyDescriptorById;
-use js::jsapi::{Handle, HandleId, HandleObject, MutableHandle, ObjectOpResult, RootedObject};
+use js::jsapi::{Handle, HandleId, HandleObject, MutableHandle, ObjectOpResult};
 use js::jsapi::{JSContext, JSObject, JSPROP_GETTER, PropertyDescriptor};
 use js::jsapi::{JSErrNum, JS_StrictPropertyStub};
 use js::jsapi::{JS_DefinePropertyById, JS_NewObjectWithGivenProto};
@@ -36,12 +36,13 @@ pub unsafe extern "C" fn get_property_descriptor(cx: *mut JSContext,
     if !InvokeGetOwnPropertyDescriptor(handler, cx, proxy, id, desc) {
         return false;
     }
-    if !desc.get().obj.is_null() {
+    if !desc.obj.is_null() {
         return true;
     }
 
-    let mut proto = RootedObject::new(cx, ptr::null_mut());
+    rooted!(in(cx) let mut proto = ptr::null_mut());
     if !GetObjectProto(cx, proxy, proto.handle_mut()) {
+        // FIXME(#11868) Should assign to desc.obj, desc.get() is a copy.
         desc.get().obj = ptr::null_mut();
         return true;
     }
@@ -65,7 +66,7 @@ pub unsafe extern "C" fn define_property(cx: *mut JSContext,
         return true;
     }
 
-    let expando = RootedObject::new(cx, ensure_expando_object(cx, proxy));
+    rooted!(in(cx) let expando = ensure_expando_object(cx, proxy));
     JS_DefinePropertyById(cx, expando.handle(), id, desc, result)
 }
 
@@ -75,8 +76,8 @@ pub unsafe extern "C" fn delete(cx: *mut JSContext,
                                 id: HandleId,
                                 bp: *mut ObjectOpResult)
                                 -> bool {
-    let expando = RootedObject::new(cx, get_expando_object(proxy));
-    if expando.ptr.is_null() {
+    rooted!(in(cx) let expando = get_expando_object(proxy));
+    if expando.is_null() {
         (*bp).code_ = 0 /* OkCode */;
         return true;
     }
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index 1d1433b2693..8816da8b099 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -465,7 +465,7 @@ impl RootedTraceableSet {
 /// Roots any JSTraceable thing
 ///
 /// If you have a valid Reflectable, use Root.
-/// If you have GC things like *mut JSObject or JSVal, use jsapi::Rooted.
+/// If you have GC things like *mut JSObject or JSVal, use rooted!.
 /// If you have an arbitrary number of Reflectables to root, use RootedVec<JS<T>>
 /// If you know what you're doing, use this.
 #[derive(JSTraceable)]
diff --git a/components/script/dom/bindings/utils.rs b/components/script/dom/bindings/utils.rs
index 0f0d5bcf00e..e7085bf424a 100644
--- a/components/script/dom/bindings/utils.rs
+++ b/components/script/dom/bindings/utils.rs
@@ -29,8 +29,8 @@ use js::jsapi::{JS_ForwardGetPropertyTo, JS_GetClass, JS_GetLatin1StringCharsAnd
 use js::jsapi::{JS_GetProperty, JS_GetPrototype, JS_GetReservedSlot, JS_HasProperty};
 use js::jsapi::{JS_HasPropertyById, JS_IsExceptionPending, JS_IsGlobalObject, JS_NewGlobalObject};
 use js::jsapi::{JS_ResolveStandardClass, JS_SetProperty, ToWindowProxyIfWindow};
-use js::jsapi::{JS_SetReservedSlot, JS_StringHasLatin1Chars, MutableHandleValue, ObjectOpResult};
-use js::jsapi::{OnNewGlobalHookOption, RootedObject, RootedValue};
+use js::jsapi::{JS_SetReservedSlot, JS_StringHasLatin1Chars, MutableHandleValue};
+use js::jsapi::{ObjectOpResult, OnNewGlobalHookOption};
 use js::jsval::{JSVal, ObjectValue, PrivateValue, UndefinedValue};
 use js::rust::{GCMethods, ToString};
 use libc;
@@ -135,8 +135,8 @@ pub fn get_property_on_prototype(cx: *mut JSContext,
                                  -> bool {
     unsafe {
         // let proto = GetObjectProto(proxy);
-        let mut proto = RootedObject::new(cx, ptr::null_mut());
-        if !JS_GetPrototype(cx, proxy, proto.handle_mut()) || proto.ptr.is_null() {
+        rooted!(in(cx) let mut proto = ptr::null_mut());
+        if !JS_GetPrototype(cx, proxy, proto.handle_mut()) || proto.is_null() {
             *found = false;
             return true;
         }
@@ -150,7 +150,7 @@ pub fn get_property_on_prototype(cx: *mut JSContext,
             return true;
         }
 
-        let receiver = RootedValue::new(cx, ObjectValue(&**proxy.ptr));
+        rooted!(in(cx) let receiver = ObjectValue(&*proxy.get()));
         JS_ForwardGetPropertyTo(cx, proto.handle(), id, receiver.handle(), vp)
     }
 }
@@ -305,29 +305,28 @@ pub fn create_dom_global(cx: *mut JSContext,
         options.creationOptions_.traceGlobal_ = trace;
         options.creationOptions_.sharedMemoryAndAtomics_ = true;
 
-        let obj =
-            RootedObject::new(cx,
-                              JS_NewGlobalObject(cx,
-                                                 class,
-                                                 ptr::null_mut(),
-                                                 OnNewGlobalHookOption::DontFireOnNewGlobalHook,
-                                                 &options));
-        if obj.ptr.is_null() {
+        rooted!(in(cx) let obj =
+            JS_NewGlobalObject(cx,
+                               class,
+                               ptr::null_mut(),
+                               OnNewGlobalHookOption::DontFireOnNewGlobalHook,
+                               &options));
+        if obj.is_null() {
             return ptr::null_mut();
         }
 
         // Initialize the reserved slots before doing amything that can GC, to
         // avoid getting trace hooks called on a partially initialized object.
-        JS_SetReservedSlot(obj.ptr, DOM_OBJECT_SLOT, PrivateValue(private));
+        JS_SetReservedSlot(obj.get(), DOM_OBJECT_SLOT, PrivateValue(private));
         let proto_array: Box<ProtoOrIfaceArray> =
             box [0 as *mut JSObject; PROTO_OR_IFACE_LENGTH];
-        JS_SetReservedSlot(obj.ptr,
+        JS_SetReservedSlot(obj.get(),
                            DOM_PROTOTYPE_SLOT,
                            PrivateValue(Box::into_raw(proto_array) as *const libc::c_void));
 
-        let _ac = JSAutoCompartment::new(cx, obj.ptr);
+        let _ac = JSAutoCompartment::new(cx, obj.get());
         JS_FireOnNewGlobalObject(cx, obj.handle());
-        obj.ptr
+        obj.get()
     }
 }
 
@@ -459,14 +458,14 @@ unsafe fn generic_call(cx: *mut JSContext,
     } else {
         GetGlobalForObjectCrossCompartment(JS_CALLEE(cx, vp).to_object_or_null())
     };
-    let obj = RootedObject::new(cx, obj);
+    rooted!(in(cx) let obj = obj);
     let info = RUST_FUNCTION_VALUE_TO_JITINFO(JS_CALLEE(cx, vp));
     let proto_id = (*info).protoID;
     let depth = (*info).depth;
     let proto_check = |class: &'static DOMClass| {
         class.interface_chain[depth as usize] as u16 == proto_id
     };
-    let this = match private_from_proto_check(obj.ptr, proto_check) {
+    let this = match private_from_proto_check(obj.get(), proto_check) {
         Ok(val) => val,
         Err(()) => {
             if is_lenient {
diff --git a/components/script/dom/browsingcontext.rs b/components/script/dom/browsingcontext.rs
index 1b78fb7572d..4c0914ddf3c 100644
--- a/components/script/dom/browsingcontext.rs
+++ b/components/script/dom/browsingcontext.rs
@@ -22,7 +22,7 @@ use js::jsapi::{Handle, HandleId, HandleObject, HandleValue, JSAutoCompartment};
 use js::jsapi::{JSContext, JSPROP_READONLY, JSErrNum, JSObject, PropertyDescriptor, JS_DefinePropertyById};
 use js::jsapi::{JS_ForwardGetPropertyTo, JS_ForwardSetPropertyTo, JS_GetClass, JSTracer, FreeOp};
 use js::jsapi::{JS_GetOwnPropertyDescriptorById, JS_HasPropertyById, MutableHandle};
-use js::jsapi::{MutableHandleValue, ObjectOpResult, RootedObject, RootedValue};
+use js::jsapi::{MutableHandleValue, ObjectOpResult};
 use js::jsval::{UndefinedValue, PrivateValue};
 use msg::constellation_msg::{PipelineId, SubpageId};
 use std::cell::Cell;
@@ -74,16 +74,15 @@ impl BrowsingContext {
             assert!(!parent.get().is_null());
             assert!(((*JS_GetClass(parent.get())).flags & JSCLASS_IS_GLOBAL) != 0);
             let _ac = JSAutoCompartment::new(cx, parent.get());
-            let window_proxy = RootedObject::new(cx,
-                NewWindowProxy(cx, parent, handler));
-            assert!(!window_proxy.ptr.is_null());
+            rooted!(in(cx) let window_proxy = NewWindowProxy(cx, parent, handler));
+            assert!(!window_proxy.is_null());
 
             let object = box BrowsingContext::new_inherited(frame_element, id);
 
             let raw = Box::into_raw(object);
-            SetProxyExtra(window_proxy.ptr, 0, &PrivateValue(raw as *const _));
+            SetProxyExtra(window_proxy.get(), 0, &PrivateValue(raw as *const _));
 
-            (*raw).init_reflector(window_proxy.ptr);
+            (*raw).init_reflector(window_proxy.get());
 
             Root::from_ref(&*raw)
         }
@@ -235,7 +234,7 @@ unsafe fn GetSubframeWindow(cx: *mut JSContext,
                             -> Option<Root<Window>> {
     let index = get_array_index_from_id(cx, id);
     if let Some(index) = index {
-        let target = RootedObject::new(cx, GetProxyPrivate(*proxy.ptr).to_object());
+        rooted!(in(cx) let target = GetProxyPrivate(*proxy.ptr).to_object());
         let win = root_from_handleobject::<Window>(target.handle()).unwrap();
         let mut found = false;
         return win.IndexedGetter(index, &mut found);
@@ -248,25 +247,26 @@ unsafe fn GetSubframeWindow(cx: *mut JSContext,
 unsafe extern "C" fn getOwnPropertyDescriptor(cx: *mut JSContext,
                                               proxy: HandleObject,
                                               id: HandleId,
-                                              desc: MutableHandle<PropertyDescriptor>)
+                                              mut desc: MutableHandle<PropertyDescriptor>)
                                               -> bool {
     let window = GetSubframeWindow(cx, proxy, id);
     if let Some(window) = window {
-        let mut val = RootedValue::new(cx, UndefinedValue());
+        rooted!(in(cx) let mut val = UndefinedValue());
         window.to_jsval(cx, val.handle_mut());
-        (*desc.ptr).value = val.ptr;
-        fill_property_descriptor(&mut *desc.ptr, *proxy.ptr, JSPROP_READONLY);
+        desc.value = val.get();
+        fill_property_descriptor(&mut desc, proxy.get(), JSPROP_READONLY);
         return true;
     }
 
-    let target = RootedObject::new(cx, GetProxyPrivate(*proxy.ptr).to_object());
+    rooted!(in(cx) let target = GetProxyPrivate(proxy.get()).to_object());
     if !JS_GetOwnPropertyDescriptorById(cx, target.handle(), id, desc) {
         return false;
     }
 
-    assert!(desc.get().obj.is_null() || desc.get().obj == target.ptr);
-    if desc.get().obj == target.ptr {
-        desc.get().obj = *proxy.ptr;
+    assert!(desc.obj.is_null() || desc.obj == target.get());
+    if desc.obj == target.get() {
+        // FIXME(#11868) Should assign to desc.obj, desc.get() is a copy.
+        desc.get().obj = proxy.get();
     }
 
     true
@@ -288,7 +288,7 @@ unsafe extern "C" fn defineProperty(cx: *mut JSContext,
         return true;
     }
 
-    let target = RootedObject::new(cx, GetProxyPrivate(*proxy.ptr).to_object());
+    rooted!(in(cx) let target = GetProxyPrivate(*proxy.ptr).to_object());
     JS_DefinePropertyById(cx, target.handle(), id, desc, res)
 }
 
@@ -304,7 +304,7 @@ unsafe extern "C" fn has(cx: *mut JSContext,
         return true;
     }
 
-    let target = RootedObject::new(cx, GetProxyPrivate(*proxy.ptr).to_object());
+    rooted!(in(cx) let target = GetProxyPrivate(*proxy.ptr).to_object());
     let mut found = false;
     if !JS_HasPropertyById(cx, target.handle(), id, &mut found) {
         return false;
@@ -327,7 +327,7 @@ unsafe extern "C" fn get(cx: *mut JSContext,
         return true;
     }
 
-    let target = RootedObject::new(cx, GetProxyPrivate(*proxy.ptr).to_object());
+    rooted!(in(cx) let target = GetProxyPrivate(*proxy.ptr).to_object());
     JS_ForwardGetPropertyTo(cx, target.handle(), id, receiver, vp)
 }
 
@@ -345,7 +345,7 @@ unsafe extern "C" fn set(cx: *mut JSContext,
         return true;
     }
 
-    let target = RootedObject::new(cx, GetProxyPrivate(*proxy.ptr).to_object());
+    rooted!(in(cx) let target = GetProxyPrivate(*proxy.ptr).to_object());
     JS_ForwardSetPropertyTo(cx,
                             target.handle(),
                             id,
diff --git a/components/script/dom/dedicatedworkerglobalscope.rs b/components/script/dom/dedicatedworkerglobalscope.rs
index dfa1672715b..87ac897a4e4 100644
--- a/components/script/dom/dedicatedworkerglobalscope.rs
+++ b/components/script/dom/dedicatedworkerglobalscope.rs
@@ -25,7 +25,7 @@ use dom::workerglobalscope::WorkerGlobalScopeInit;
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
 use js::jsapi::{HandleValue, JS_SetInterruptCallback};
-use js::jsapi::{JSAutoCompartment, JSContext, RootedValue};
+use js::jsapi::{JSAutoCompartment, JSContext};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
 use msg::constellation_msg::PipelineId;
@@ -290,7 +290,7 @@ impl DedicatedWorkerGlobalScope {
                 let target = self.upcast();
                 let _ac = JSAutoCompartment::new(scope.get_cx(),
                                                  scope.reflector().get_jsobject().get());
-                let mut message = RootedValue::new(scope.get_cx(), UndefinedValue());
+                rooted!(in(scope.get_cx()) let mut message = UndefinedValue());
                 data.read(GlobalRef::Worker(scope), message.handle_mut());
                 MessageEvent::dispatch_jsval(target, GlobalRef::Worker(scope), message.handle());
             },
diff --git a/components/script/dom/errorevent.rs b/components/script/dom/errorevent.rs
index f6c5802ca29..61db675f551 100644
--- a/components/script/dom/errorevent.rs
+++ b/components/script/dom/errorevent.rs
@@ -13,7 +13,7 @@ use dom::bindings::js::{MutHeapJSVal, Root};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::{Event, EventBubbles, EventCancelable};
-use js::jsapi::{RootedValue, HandleValue, JSContext};
+use js::jsapi::{HandleValue, JSContext};
 use js::jsval::JSVal;
 use std::cell::Cell;
 use string_cache::Atom;
@@ -93,7 +93,7 @@ impl ErrorEvent {
 
         // Dictionaries need to be rooted
         // https://github.com/servo/servo/issues/6381
-        let error = RootedValue::new(global.get_cx(), init.error);
+        rooted!(in(global.get_cx()) let error = init.error);
         let event = ErrorEvent::new(global, Atom::from(type_),
                                 bubbles, cancelable,
                                 msg, file_name,
diff --git a/components/script/dom/eventtarget.rs b/components/script/dom/eventtarget.rs
index 9f41abee7d7..0175023deb1 100644
--- a/components/script/dom/eventtarget.rs
+++ b/components/script/dom/eventtarget.rs
@@ -29,7 +29,7 @@ use dom::virtualmethods::VirtualMethods;
 use dom::window::Window;
 use fnv::FnvHasher;
 use heapsize::HeapSizeOf;
-use js::jsapi::{CompileFunction, JS_GetFunctionObject, RootedValue, RootedFunction, JSAutoCompartment};
+use js::jsapi::{CompileFunction, JS_GetFunctionObject, JSAutoCompartment};
 use js::rust::{AutoObjectVectorWrapper, CompileOptionsWrapper};
 use libc::{c_char, size_t};
 use std::collections::HashMap;
@@ -156,7 +156,7 @@ impl CompiledEventListener {
                         if let Some(event) = event.downcast::<ErrorEvent>() {
                             let global = object.global();
                             let cx = global.r().get_cx();
-                            let error = RootedValue::new(cx, event.Error(cx));
+                            rooted!(in(cx) let error = event.Error(cx));
                             let return_value = handler.Call_(object,
                                                              EventOrString::String(event.Message()),
                                                              Some(event.Filename()),
@@ -166,7 +166,7 @@ impl CompiledEventListener {
                                                              exception_handle);
                             // Step 4
                             if let Ok(return_value) = return_value {
-                                let return_value = RootedValue::new(cx, return_value);
+                                rooted!(in(cx) let return_value = return_value);
                                 if return_value.handle().is_boolean() && return_value.handle().to_boolean() == true {
                                     event.upcast::<Event>().PreventDefault();
                                 }
@@ -203,7 +203,7 @@ impl CompiledEventListener {
                         if let Ok(value) = handler.Call_(object, event, exception_handle) {
                             let global = object.global();
                             let cx = global.r().get_cx();
-                            let value = RootedValue::new(cx, value);
+                            rooted!(in(cx) let value = value);
                             let value = value.handle();
 
                             //Step 4
@@ -411,7 +411,7 @@ impl EventTarget {
         let scopechain = AutoObjectVectorWrapper::new(cx);
 
         let _ac = JSAutoCompartment::new(cx, window.reflector().get_jsobject().get());
-        let mut handler = RootedFunction::new(cx, ptr::null_mut());
+        rooted!(in(cx) let mut handler = ptr::null_mut());
         let rv = unsafe {
             CompileFunction(cx,
                             scopechain.ptr,
@@ -423,7 +423,7 @@ impl EventTarget {
                             body.len() as size_t,
                             handler.handle_mut())
         };
-        if !rv || handler.ptr.is_null() {
+        if !rv || handler.get().is_null() {
             // Step 1.8.2
             unsafe {
                 report_pending_exception(cx, self.reflector().get_jsobject().get());
@@ -433,7 +433,7 @@ impl EventTarget {
         }
 
         // TODO step 1.11-13
-        let funobj = unsafe { JS_GetFunctionObject(handler.ptr) };
+        let funobj = unsafe { JS_GetFunctionObject(handler.get()) };
         assert!(!funobj.is_null());
         // Step 1.14
         if is_error {
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index 2c71488c5dc..8289edd3081 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -36,7 +36,7 @@ use dom::urlhelper::UrlHelper;
 use dom::virtualmethods::VirtualMethods;
 use dom::window::{ReflowReason, Window};
 use ipc_channel::ipc;
-use js::jsapi::{JSAutoCompartment, RootedValue, JSContext, MutableHandleValue};
+use js::jsapi::{JSAutoCompartment, JSContext, MutableHandleValue};
 use js::jsval::{UndefinedValue, NullValue};
 use msg::constellation_msg::{FrameType, LoadData, NavigationDirection, PipelineId, SubpageId};
 use net_traits::response::HttpsState;
@@ -171,7 +171,7 @@ impl HTMLIFrameElement {
             let custom_event = unsafe {
                 let cx = window.get_cx();
                 let _ac = JSAutoCompartment::new(cx, window.reflector().get_jsobject().get());
-                let mut detail = RootedValue::new(cx, UndefinedValue());
+                rooted!(in(cx) let mut detail = UndefinedValue());
                 let event_name = Atom::from(event.name());
                 self.build_mozbrowser_event_detail(event, cx, detail.handle_mut());
                 CustomEvent::new(GlobalRef::Window(window.r()),
diff --git a/components/script/dom/htmlscriptelement.rs b/components/script/dom/htmlscriptelement.rs
index f280f670e4b..5aeb607ee93 100644
--- a/components/script/dom/htmlscriptelement.rs
+++ b/components/script/dom/htmlscriptelement.rs
@@ -30,7 +30,6 @@ use html5ever::tree_builder::NextParserState;
 use hyper::http::RawStatus;
 use ipc_channel::ipc;
 use ipc_channel::router::ROUTER;
-use js::jsapi::RootedValue;
 use js::jsval::UndefinedValue;
 use net_traits::{AsyncResponseListener, AsyncResponseTarget, Metadata, NetworkError};
 use network_listener::{NetworkListener, PreInvoke};
@@ -441,7 +440,7 @@ impl HTMLScriptElement {
         // Step 2.b.6.
         // TODO: Create a script...
         let window = window_from_node(self);
-        let mut rval = RootedValue::new(window.get_cx(), UndefinedValue());
+        rooted!(in(window.get_cx()) let mut rval = UndefinedValue());
         window.evaluate_script_on_global_with_result(&*source,
                                                          url.as_str(),
                                                          rval.handle_mut());
diff --git a/components/script/dom/messageevent.rs b/components/script/dom/messageevent.rs
index 8d638adae06..b5b46fba5d8 100644
--- a/components/script/dom/messageevent.rs
+++ b/components/script/dom/messageevent.rs
@@ -13,7 +13,7 @@ use dom::bindings::reflector::reflect_dom_object;
 use dom::bindings::str::DOMString;
 use dom::event::Event;
 use dom::eventtarget::EventTarget;
-use js::jsapi::{RootedValue, HandleValue, Heap, JSContext};
+use js::jsapi::{HandleValue, Heap, JSContext};
 use js::jsval::JSVal;
 use std::default::Default;
 use string_cache::Atom;
@@ -66,7 +66,7 @@ impl MessageEvent {
                        -> Fallible<Root<MessageEvent>> {
         // Dictionaries need to be rooted
         // https://github.com/servo/servo/issues/6381
-        let data = RootedValue::new(global.get_cx(), init.data);
+        rooted!(in(global.get_cx()) let data = init.data);
         let ev = MessageEvent::new(global, Atom::from(type_), init.parent.bubbles, init.parent.cancelable,
                                    data.handle(),
                                    init.origin.clone(), init.lastEventId.clone());
diff --git a/components/script/dom/serviceworker.rs b/components/script/dom/serviceworker.rs
index 5122bcf5f0d..ad303d45915 100644
--- a/components/script/dom/serviceworker.rs
+++ b/components/script/dom/serviceworker.rs
@@ -20,7 +20,6 @@ use dom::eventtarget::EventTarget;
 use dom::serviceworkerglobalscope::ServiceWorkerGlobalScope;
 use dom::workerglobalscope::prepare_workerscope_init;
 use ipc_channel::ipc;
-use js::jsapi::RootedValue;
 use js::jsval::UndefinedValue;
 use script_thread::Runnable;
 use std::cell::Cell;
@@ -91,7 +90,7 @@ impl ServiceWorker {
         }
 
         let global = worker.r().global();
-        let error = RootedValue::new(global.r().get_cx(), UndefinedValue());
+        rooted!(in(global.r().get_cx()) let error = UndefinedValue());
         let errorevent = ErrorEvent::new(global.r(), atom!("error"),
                                          EventBubbles::Bubbles, EventCancelable::Cancelable,
                                          message, filename, lineno, colno, error.handle());
diff --git a/components/script/dom/serviceworkerglobalscope.rs b/components/script/dom/serviceworkerglobalscope.rs
index 4039be05403..a0f328aa607 100644
--- a/components/script/dom/serviceworkerglobalscope.rs
+++ b/components/script/dom/serviceworkerglobalscope.rs
@@ -23,7 +23,7 @@ use dom::workerglobalscope::WorkerGlobalScope;
 use dom::workerglobalscope::WorkerGlobalScopeInit;
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
-use js::jsapi::{JS_SetInterruptCallback, JSAutoCompartment, JSContext, RootedValue};
+use js::jsapi::{JS_SetInterruptCallback, JSAutoCompartment, JSContext};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
 use msg::constellation_msg::PipelineId;
@@ -283,7 +283,7 @@ impl ServiceWorkerGlobalScope {
                 let target = self.upcast();
                 let _ac = JSAutoCompartment::new(scope.get_cx(),
                                                  scope.reflector().get_jsobject().get());
-                let mut message = RootedValue::new(scope.get_cx(), UndefinedValue());
+                rooted!(in(scope.get_cx()) let mut message = UndefinedValue());
                 data.read(GlobalRef::Worker(scope), message.handle_mut());
                 MessageEvent::dispatch_jsval(target, GlobalRef::Worker(scope), message.handle());
             },
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index 686bf43178f..cf814068b22 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -33,7 +33,7 @@ use dom::webgltexture::{TexParameterValue, WebGLTexture};
 use dom::webgluniformlocation::WebGLUniformLocation;
 use euclid::size::Size2D;
 use ipc_channel::ipc::{self, IpcSender};
-use js::jsapi::{JSContext, JS_GetArrayBufferViewType, JSObject, RootedValue, Type};
+use js::jsapi::{JSContext, JS_GetArrayBufferViewType, JSObject, Type};
 use js::jsval::{BooleanValue, DoubleValue, Int32Value, JSVal, NullValue, UndefinedValue};
 use net_traits::image::base::PixelFormat;
 use net_traits::image_cache_thread::ImageResponse;
@@ -522,11 +522,11 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
             WebGLParameter::Float(val) => DoubleValue(val as f64),
             WebGLParameter::FloatArray(_) => panic!("Parameter should not be float array"),
             WebGLParameter::String(val) => {
-                let mut rval = RootedValue::new(cx, UndefinedValue());
+                rooted!(in(cx) let mut rval = UndefinedValue());
                 unsafe {
                     val.to_jsval(cx, rval.handle_mut());
                 }
-                rval.ptr
+                rval.get()
             }
             WebGLParameter::Invalid => NullValue(),
         }
@@ -1267,13 +1267,13 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
     fn GetVertexAttrib(&self, cx: *mut JSContext, index: u32, pname: u32) -> JSVal {
         if index == 0 && pname == constants::CURRENT_VERTEX_ATTRIB {
-            let mut result = RootedValue::new(cx, UndefinedValue());
+            rooted!(in(cx) let mut result = UndefinedValue());
             let (x, y, z, w) = self.current_vertex_attrib_0.get();
             let attrib = vec![x, y, z, w];
             unsafe {
                 attrib.to_jsval(cx, result.handle_mut());
             }
-            return result.ptr
+            return result.get()
         }
 
         let (sender, receiver) = ipc::channel().unwrap();
@@ -1285,11 +1285,11 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
             WebGLParameter::String(_) => panic!("Vertex attrib should not be string"),
             WebGLParameter::Float(_) => panic!("Vertex attrib should not be float"),
             WebGLParameter::FloatArray(val) => {
-                let mut result = RootedValue::new(cx, UndefinedValue());
+                rooted!(in(cx) let mut result = UndefinedValue());
                 unsafe {
                     val.to_jsval(cx, result.handle_mut());
                 }
-                result.ptr
+                result.get()
             }
             WebGLParameter::Invalid => NullValue(),
         }
diff --git a/components/script/dom/websocket.rs b/components/script/dom/websocket.rs
index 1409936c6c7..cc8c6f74d54 100644
--- a/components/script/dom/websocket.rs
+++ b/components/script/dom/websocket.rs
@@ -23,7 +23,7 @@ use dom::eventtarget::EventTarget;
 use dom::messageevent::MessageEvent;
 use dom::urlhelper::UrlHelper;
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
-use js::jsapi::{JSAutoCompartment, RootedValue};
+use js::jsapi::JSAutoCompartment;
 use js::jsapi::{JS_GetArrayBufferData, JS_NewArrayBuffer};
 use js::jsval::UndefinedValue;
 use libc::{uint32_t, uint8_t};
@@ -585,7 +585,7 @@ impl Runnable for MessageReceivedTask {
         unsafe {
             let cx = global.r().get_cx();
             let _ac = JSAutoCompartment::new(cx, ws.reflector().get_jsobject().get());
-            let mut message = RootedValue::new(cx, UndefinedValue());
+            rooted!(in(cx) let mut message = UndefinedValue());
             match self.message {
                 MessageData::Text(text) => text.to_jsval(cx, message.handle_mut()),
                 MessageData::Binary(data) => {
diff --git a/components/script/dom/worker.rs b/components/script/dom/worker.rs
index a136f4ec8ca..2cf1d1c4e46 100644
--- a/components/script/dom/worker.rs
+++ b/components/script/dom/worker.rs
@@ -23,7 +23,7 @@ use dom::eventtarget::EventTarget;
 use dom::messageevent::MessageEvent;
 use dom::workerglobalscope::prepare_workerscope_init;
 use ipc_channel::ipc;
-use js::jsapi::{HandleValue, JSContext, RootedValue, JSAutoCompartment};
+use js::jsapi::{HandleValue, JSContext, JSAutoCompartment};
 use js::jsval::UndefinedValue;
 use script_thread::Runnable;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -115,7 +115,7 @@ impl Worker {
         let global = worker.r().global();
         let target = worker.upcast();
         let _ac = JSAutoCompartment::new(global.r().get_cx(), target.reflector().get_jsobject().get());
-        let mut message = RootedValue::new(global.r().get_cx(), UndefinedValue());
+        rooted!(in(global.r().get_cx()) let mut message = UndefinedValue());
         data.read(global.r(), message.handle_mut());
         MessageEvent::dispatch_jsval(target, global.r(), message.handle());
     }
@@ -134,7 +134,7 @@ impl Worker {
         }
 
         let global = worker.r().global();
-        let error = RootedValue::new(global.r().get_cx(), UndefinedValue());
+        rooted!(in(global.r().get_cx()) let error = UndefinedValue());
         let errorevent = ErrorEvent::new(global.r(), atom!("error"),
                                          EventBubbles::Bubbles, EventCancelable::Cancelable,
                                          message, filename, lineno, colno, error.handle());
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index a9106d36206..2e1c983bfd4 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -21,7 +21,7 @@ use dom::workerlocation::WorkerLocation;
 use dom::workernavigator::WorkerNavigator;
 use ipc_channel::ipc::{self, IpcSender};
 use ipc_channel::router::ROUTER;
-use js::jsapi::{HandleValue, JSContext, JSRuntime, RootedValue};
+use js::jsapi::{HandleValue, JSContext, JSRuntime};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
 use msg::constellation_msg::{PipelineId, ReferrerPolicy, PanicMsg};
@@ -309,7 +309,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
             };
         }
 
-        let mut rval = RootedValue::new(self.runtime.cx(), UndefinedValue());
+        rooted!(in(self.runtime.cx()) let mut rval = UndefinedValue());
         for url in urls {
             let (url, source) = match load_whole_resource(LoadContext::Script,
                                                           &self.resource_threads.sender(),
@@ -420,7 +420,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
 impl WorkerGlobalScope {
     #[allow(unsafe_code)]
     pub fn execute_script(&self, source: DOMString) {
-        let mut rval = RootedValue::new(self.runtime.cx(), UndefinedValue());
+        rooted!(in(self.runtime.cx()) let mut rval = UndefinedValue());
         match self.runtime.evaluate_script(
             self.reflector().get_jsobject(), &source, self.worker_url.as_str(), 1, rval.handle_mut()) {
             Ok(_) => (),
diff --git a/components/script/dom/xmlhttprequest.rs b/components/script/dom/xmlhttprequest.rs
index af424fb83d7..1e95250149d 100644
--- a/components/script/dom/xmlhttprequest.rs
+++ b/components/script/dom/xmlhttprequest.rs
@@ -40,7 +40,7 @@ use hyper::mime::{self, Mime, Attr as MimeAttr, Value as MimeValue};
 use ipc_channel::ipc;
 use ipc_channel::router::ROUTER;
 use js::jsapi::JS_ClearPendingException;
-use js::jsapi::{JSContext, JS_ParseJSON, RootedValue};
+use js::jsapi::{JSContext, JS_ParseJSON};
 use js::jsval::{JSVal, NullValue, UndefinedValue};
 use msg::constellation_msg::{PipelineId, ReferrerPolicy};
 use net_traits::CoreResourceMsg::Fetch;
@@ -772,7 +772,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
     // https://xhr.spec.whatwg.org/#the-response-attribute
     fn Response(&self, cx: *mut JSContext) -> JSVal {
         unsafe {
-            let mut rval = RootedValue::new(cx, UndefinedValue());
+            rooted!(in(cx) let mut rval = UndefinedValue());
             match self.response_type.get() {
                 XMLHttpRequestResponseType::_empty | XMLHttpRequestResponseType::Text => {
                     let ready_state = self.ready_state.get();
@@ -809,7 +809,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
                     self.response.borrow().to_jsval(cx, rval.handle_mut());
                 }
             }
-            rval.ptr
+            rval.get()
         }
     }
 
@@ -1177,7 +1177,7 @@ impl XMLHttpRequest {
         let json_text = UTF_8.decode(&bytes, DecoderTrap::Replace).unwrap();
         let json_text: Vec<u16> = json_text.encode_utf16().collect();
         // Step 5
-        let mut rval = RootedValue::new(cx, UndefinedValue());
+        rooted!(in(cx) let mut rval = UndefinedValue());
         unsafe {
             if !JS_ParseJSON(cx,
                              json_text.as_ptr(),
@@ -1188,7 +1188,7 @@ impl XMLHttpRequest {
             }
         }
         // Step 6
-        self.response_json.set(rval.ptr);
+        self.response_json.set(rval.get());
         self.response_json.get()
     }
 
diff --git a/components/script/lib.rs b/components/script/lib.rs
index 4823b2f475f..ebc5b4a1686 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -50,6 +50,7 @@ extern crate html5ever;
 extern crate hyper;
 extern crate image;
 extern crate ipc_channel;
+#[macro_use]
 extern crate js;
 extern crate libc;
 #[macro_use]
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 96555524c5d..7a23867fc8b 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -58,7 +58,7 @@ use hyper::mime::{Mime, SubLevel, TopLevel};
 use ipc_channel::ipc::{self, IpcSender};
 use ipc_channel::router::ROUTER;
 use js::glue::GetWindowProxyClass;
-use js::jsapi::{DOMProxyShadowsResult, HandleId, HandleObject, RootedValue};
+use js::jsapi::{DOMProxyShadowsResult, HandleId, HandleObject};
 use js::jsapi::{JSAutoCompartment, JSContext, JS_SetWrapObjectCallbacks};
 use js::jsapi::{JSTracer, SetWindowProxyClass};
 use js::jsval::UndefinedValue;
@@ -1747,7 +1747,7 @@ impl ScriptThread {
             // Script source is ready to be evaluated (11.)
             unsafe {
                 let _ac = JSAutoCompartment::new(self.get_cx(), window.reflector().get_jsobject().get());
-                let mut jsval = RootedValue::new(self.get_cx(), UndefinedValue());
+                rooted!(in(self.get_cx()) let mut jsval = UndefinedValue());
                 window.evaluate_js_on_global_with_result(&script_source, jsval.handle_mut());
                 let strval = DOMString::from_jsval(self.get_cx(),
                                                    jsval.handle(),
diff --git a/components/script/timers.rs b/components/script/timers.rs
index 989382e80fe..f2562bdf9d5 100644
--- a/components/script/timers.rs
+++ b/components/script/timers.rs
@@ -13,7 +13,7 @@ use dom::xmlhttprequest::XHRTimeoutCallback;
 use euclid::length::Length;
 use heapsize::HeapSizeOf;
 use ipc_channel::ipc::IpcSender;
-use js::jsapi::{HandleValue, Heap, RootedValue};
+use js::jsapi::{HandleValue, Heap};
 use js::jsval::{JSVal, UndefinedValue};
 use script_traits::{MsDuration, precise_time_ms};
 use script_traits::{TimerEvent, TimerEventId, TimerEventRequest, TimerSource};
@@ -488,7 +488,7 @@ impl JsTimerTask {
         match *&self.callback {
             InternalTimerCallback::StringTimerCallback(ref code_str) => {
                 let cx = this.global().r().get_cx();
-                let mut rval = RootedValue::new(cx, UndefinedValue());
+                rooted!(in(cx) let mut rval = UndefinedValue());
 
                 this.evaluate_js_on_global_with_result(code_str, rval.handle_mut());
             },
diff --git a/components/script/webdriver_handlers.rs b/components/script/webdriver_handlers.rs
index 1c320b5be06..fe19f52fafa 100644
--- a/components/script/webdriver_handlers.rs
+++ b/components/script/webdriver_handlers.rs
@@ -28,8 +28,7 @@ use euclid::point::Point2D;
 use euclid::rect::Rect;
 use euclid::size::Size2D;
 use ipc_channel::ipc::{self, IpcSender};
-use js::jsapi::JSContext;
-use js::jsapi::{HandleValue, RootedValue};
+use js::jsapi::{JSContext, HandleValue};
 use js::jsval::UndefinedValue;
 use msg::constellation_msg::PipelineId;
 use msg::webdriver_msg::WebDriverCookieError;
@@ -77,7 +76,7 @@ pub fn handle_execute_script(context: &BrowsingContext,
     let window = context.active_window();
     let result = unsafe {
         let cx = window.get_cx();
-        let mut rval = RootedValue::new(cx, UndefinedValue());
+        rooted!(in(cx) let mut rval = UndefinedValue());
         window.evaluate_js_on_global_with_result(&eval, rval.handle_mut());
         jsval_to_webdriver(cx, rval.handle())
     };
@@ -92,7 +91,7 @@ pub fn handle_execute_async_script(context: &BrowsingContext,
     let window = context.active_window();
     let cx = window.get_cx();
     window.set_webdriver_script_chan(Some(reply));
-    let mut rval = RootedValue::new(cx, UndefinedValue());
+    rooted!(in(cx) let mut rval = UndefinedValue());
     window.evaluate_js_on_global_with_result(&eval, rval.handle_mut());
 }
 
diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index 7103bee63c9..c9eeb43ceed 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -1074,7 +1074,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.3"
-source = "git+https://github.com/servo/rust-mozjs#707bfb4ff4fe2c0abde1cc2bb87ac35ff8f40aaa"
+source = "git+https://github.com/servo/rust-mozjs#7ccfee50f407841b8cd03b6520a2b9db866ac90a"
 dependencies = [
  "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index 8f36c4363c7..28d1484a9c5 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -983,7 +983,7 @@ dependencies = [
 [[package]]
 name = "js"
 version = "0.1.3"
-source = "git+https://github.com/servo/rust-mozjs#707bfb4ff4fe2c0abde1cc2bb87ac35ff8f40aaa"
+source = "git+https://github.com/servo/rust-mozjs#7ccfee50f407841b8cd03b6520a2b9db866ac90a"
 dependencies = [
  "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",