diff --git a/js/src/jsapi-tests/testOps.cpp b/js/src/jsapi-tests/testOps.cpp
new file mode 100644
index 000000000000..e58b14a4f822
--- /dev/null
+++ b/js/src/jsapi-tests/testOps.cpp
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sw=4 et tw=99:
+ *
+ * Tests for operators and implicit type conversion.
+ */
+
+#include "tests.h"
+
+static JSBool
+my_convert(JSContext* context, JSObject* obj, JSType type, jsval* rval)
+{
+    if (type == JSTYPE_VOID || type == JSTYPE_STRING || type == JSTYPE_NUMBER || type == JSTYPE_BOOLEAN)
+        return JS_NewNumberValue(context, 123, rval);
+    return JS_FALSE;
+}
+
+static JSClass myClass = {
+    "MyClass",
+    0,
+    JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_PropertyStub,
+    JS_EnumerateStub, JS_ResolveStub, my_convert, JS_FinalizeStub,
+    JSCLASS_NO_OPTIONAL_MEMBERS
+};
+
+static JSBool
+createMyObject(JSContext* context, JSObject* obj, uintN argc, jsval *argv, jsval* rval)
+{
+    JS_BeginRequest(context);
+
+    //JS_GC(context); //<- if we make GC here, all is ok
+
+    JSObject* myObject = JS_NewObject(context, &myClass, NULL, NULL);
+    *rval = OBJECT_TO_JSVAL(myObject);
+
+    JS_EndRequest(context);
+
+    return JS_TRUE;
+}
+
+static JSFunctionSpec s_functions[] =
+{
+    { "createMyObject", createMyObject, 0 },
+    { 0,0,0,0,0 }
+};
+
+BEGIN_TEST(testOps_bug559006)
+{
+    CHECK(JS_DefineFunctions(cx, global, s_functions));
+
+    EXEC("function main() { while(1) return 0 + createMyObject(); }");
+
+    for (int i = 0; i < 9; i++) {
+        jsvalRoot rval(cx);
+        CHECK(JS_CallFunctionName(cx, global, "main", 0, NULL, rval.addr()));
+        CHECK_SAME(rval, INT_TO_JSVAL(123));
+    }
+    return true;
+}
+END_TEST(testOps_bug559006)
+