diff --git a/components/plugins/jstraceable.rs b/components/plugins/jstraceable.rs
index 7f4757816e0..4c23a1897a5 100644
--- a/components/plugins/jstraceable.rs
+++ b/components/plugins/jstraceable.rs
@@ -42,6 +42,7 @@ pub fn expand_jstraceable(cx: &mut ExtCtxt, span: Span, mitem: &MetaItem, item:
                 args: vec!(ty::Ptr(box ty::Literal(ty::Path::new(vec!("js","jsapi","JSTracer"))), ty::Raw(ast::MutMutable))),
                 ret_ty: ty::nil_ty(),
                 attributes: vec![quote_attr!(cx, #[inline(always)])],
+                is_unsafe: false,
                 combine_substructure: combine_substructure(box jstraceable_substructure)
             }
         ],