tribute DOMString foo; };");
        context.add_idls("interface C { [Default] object toJSON(); attribute long foo; };");
        var map = context.members.A.default_to_json_operation();
        assert_equals(map.size, 1);
        assert_true(map.has("foo"));
        assert_equals(map.get("foo").idlType, "DOMString");
    }, 'attributes declared further away in the inheritance hierarchy should be masked by attributes declared closer');

    test(function() {
        var context = new IdlArray();
        con