diff --git a/servo/components/script/dom/bindings/trace.rs b/servo/components/script/dom/bindings/trace.rs
index df681e3add9f..b566e972ec2d 100644
--- a/servo/components/script/dom/bindings/trace.rs
+++ b/servo/components/script/dom/bindings/trace.rs
@@ -425,6 +425,13 @@ unsafe impl<A, B> JSTraceable for fn(A) -> B {
     }
 }
 
+unsafe impl<'a, A, B> JSTraceable for fn(&A) -> B {
+    #[inline]
+    unsafe fn trace(&self, _: *mut JSTracer) {
+        // Do nothing
+    }
+}
+
 unsafe impl<T> JSTraceable for IpcSender<T> where T: for<'de> Deserialize<'de> + Serialize {
     #[inline]
     unsafe fn trace(&self, _: *mut JSTracer) {
diff --git a/servo/components/script_plugins/utils.rs b/servo/components/script_plugins/utils.rs
index 4f6fce2d0edf..45a348ea14f8 100644
--- a/servo/components/script_plugins/utils.rs
+++ b/servo/components/script_plugins/utils.rs
@@ -29,7 +29,7 @@ pub fn match_def_path(cx: &LateContext, def_id: DefId, path: &[&str]) -> bool {
 }
 
 pub fn in_derive_expn(span: Span) -> bool {
-    if let Some(i) = span.ctxt.outer().expn_info() {
+    if let Some(i) = span.ctxt().outer().expn_info() {
         if let ExpnFormat::MacroAttribute(n) = i.callee.format {
             n.as_str().contains("derive")
         } else {
diff --git a/servo/rust-toolchain b/servo/rust-toolchain
index 202c6314dd99..009c84eceb4f 100644
--- a/servo/rust-toolchain
+++ b/servo/rust-toolchain
@@ -1 +1 @@
-nightly-2017-08-30
+nightly-2017-08-31