diff --git a/js/src/irregexp/imported/regexp-compiler.h b/js/src/irregexp/imported/regexp-compiler.h
index 88dc915ece02..65e2111cf51f 100644
--- a/imported/regexp-compiler.h
+++ b/imported/regexp-compiler.h
@@ -344,4 +344,7 @@ class Trace {
     bool operator==(const ConstIterator& other) const {
       return trace_ == other.trace_;
     }
+    bool operator!=(const ConstIterator& other) const {
+      return !(*this == other);
+    }
     const Trace* operator*() const { return trace_; }

    private: