parseBindingElementList_(elements) {
    this.parseElisionOpt_(elements);
    elements.push(this.parseBindingElement_());
    while (this.eatIf_(COMMA)) {
      this.parseElisionOpt_(elements);
      elements.push(this.parseBindingElement_());
    }
  }
BindingElementList :
  Elisionopt BindingElement
  BindingElementList , Elisionopt BindingElement