function MyClass() {
    if (_biInPrototype) return;
    BiComponent.call(this);

    var x = new BiComboBox();
    x = new BiLabel();              // Should complain here about redeclaration

    this._y = new BiComboBox();
}
_p = _biExtend(MyClass, BiComponent, "MyClass");

_p.someMethod = function() {
    this._y = new BiLabel();        // should complain here about redeclaration
};