code: function isSelectWithModel (node) {
    return (
      node.type === 1 &&
      node.tag === 'select' &&
      node.directives != null &&
      node.directives.some(function (d) { return d.name === 'model'; })
    )
  }
docs: <select v-model> cannot be optimized because it requires a runtime check to determine proper selected option