--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -4547,17 +4547,17 @@ class ShellAutoEntryMonitor : JS::dbg::A
     void Entry(JSContext* cx, JSScript* script) override {
         MOZ_ASSERT(!enteredWithoutExit);
         enteredWithoutExit = true;
 
         UniqueChars label(JS_smprintf("eval:%s", JS_GetScriptFilename(script)));
         oom = !label || !log.append(mozilla::Move(label));
     }
 
-    void Exit(JSContext* cx) {
+    void Exit(JSContext* cx) override {
         MOZ_ASSERT(enteredWithoutExit);
         enteredWithoutExit = false;
     }
 
     bool buildResult(JSContext *cx, MutableHandleValue resultValue) {
         if (oom) {
             JS_ReportOutOfMemory(cx);
             return false;