peration();
        assert_equals(map.size, 1);
        assert_true(map.has("b"));
        assert_equals(map.get("b").idlType, "long");
        assert_array_equals([...map.keys()], ["b"]);
    }, 'should not include attributes of the current interface when the [Default] toJSON method in inherited');

    test(function() {
        var context = new IdlArray();
        context.add_idls("interface A : B { [Default] object toJSON(); };");
        context.add_idls("interface B : C { [Default] object toJSON(); at