1 files changed, 16 insertions, 0 deletions
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index 4fecf083737..ae1a9e6e3b4 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -61,6 +61,7 @@ use html5ever::{LocalName, Namespace, Prefix, QualName};
 use http::header::HeaderMap;
 use hyper::Method;
 use hyper::StatusCode;
+use indexmap::IndexMap;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use js::glue::{CallObjectTracer, CallValueTracer};
 use js::jsapi::{GCTraceKindToAscii, Heap, JSObject, JSTracer, TraceKind};
@@ -356,6 +357,21 @@ unsafe impl<K: Ord + JSTraceable, V: JSTraceable> JSTraceable for BTreeMap<K, V>
     }
 }
 
+unsafe impl<K, V, S> JSTraceable for IndexMap<K, V, S>
+where
+    K: Hash + Eq + JSTraceable,
+    V: JSTraceable,
+    S: BuildHasher,
+{
+    #[inline]
+    unsafe fn trace(&self, trc: *mut JSTracer) {
+        for (k, v) in &*self {
+            k.trace(trc);
+            v.trace(trc);
+        }
+    }
+}
+
 unsafe impl<A: JSTraceable, B: JSTraceable> JSTraceable for (A, B) {
     #[inline]
     unsafe fn trace(&self, trc: *mut JSTracer) {