3 files changed, 20 insertions, 29 deletions
diff --git a/components/script/dom/bindings/js.rs b/components/script/dom/bindings/js.rs
index 1736758e739..d171715d474 100644
--- a/components/script/dom/bindings/js.rs
+++ b/components/script/dom/bindings/js.rs
@@ -606,6 +606,12 @@ impl<T: Reflectable> PartialEq for Root<T> {
     }
 }
 
+impl<T: Reflectable> Clone for Root<T> {
+    fn clone(&self) -> Root<T> {
+        Root::from_ref(&*self)
+    }
+}
+
 impl<T: Reflectable> Drop for Root<T> {
     fn drop(&mut self) {
         unsafe {
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 99648369357..748b7b8249e 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -1166,34 +1166,20 @@ impl Iterator for PrecedingNodeIterator {
             Some(current) => current,
         };
 
-        if self.root == current {
-            self.current = None;
-            return None
-        }
-
-        let node = current;
-        if let Some(previous_sibling) = node.GetPreviousSibling() {
+        self.current = if self.root == current {
+            None
+        } else if let Some(previous_sibling) = current.GetPreviousSibling() {
             if self.root == previous_sibling {
-                self.current = None;
-                return None
-            }
-
-            if let Some(last_child) = previous_sibling.descending_last_children().last() {
-                self.current = Some(last_child);
-                return previous_sibling.descending_last_children().last()
+                None
+            } else if let Some(last_child) = previous_sibling.descending_last_children().last() {
+                Some(last_child)
+            } else {
+                Some(previous_sibling)
             }
-
-            self.current = Some(previous_sibling);
-            return node.GetPreviousSibling()
+        } else {
+            current.GetParentNode()
         };
-
-        if let Some(parent_node) = node.GetParentNode() {
-            self.current = Some(parent_node);
-            return node.GetParentNode()
-        }
-
-        self.current = None;
-        None
+        self.current.clone()
     }
 }
 
diff --git a/components/script/dom/xmldocument.rs b/components/script/dom/xmldocument.rs
index 8f614a0442c..9d156682fa2 100644
--- a/components/script/dom/xmldocument.rs
+++ b/components/script/dom/xmldocument.rs
@@ -4,7 +4,6 @@
 
 use document_loader::DocumentLoader;
 use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
-use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::Bindings::XMLDocumentBinding::{self, XMLDocumentMethods};
 use dom::bindings::global::GlobalRef;
 use dom::bindings::inheritance::Castable;
@@ -77,16 +76,16 @@ impl XMLDocument {
 impl XMLDocumentMethods for XMLDocument {
     // https://html.spec.whatwg.org/multipage/#dom-document-location
     fn GetLocation(&self) -> Option<Root<Location>> {
-        self.document.GetLocation()
+        self.upcast::<Document>().GetLocation()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-tree-accessors:supported-property-names
     fn SupportedPropertyNames(&self) -> Vec<DOMString> {
-        self.document.SupportedPropertyNames()
+        self.upcast::<Document>().SupportedPropertyNames()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-tree-accessors:dom-document-nameditem-filter
     fn NamedGetter(&self, _cx: *mut JSContext, name: DOMString, found: &mut bool) -> *mut JSObject {
-        self.document.NamedGetter(_cx, name, found)
+        self.upcast::<Document>().NamedGetter(_cx, name, found)
     }
 }