父组件把data里的a值与子组件的b值进行绑定，子组件再将b值与孙组件的c值进行绑定，当父组件改变a值时，微信小程序报错，而h5却没有报错
报错信息：
VM124:1 [Vue warn]: Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders. Instead, use a data or computed property based on the prop's value. Prop being mutated: "isb"
