antd 3.26.19 mapPropsToFields and Form validation

[backloz]

The antd website has the following code example:
https://codesandbox.io/s/hx459?file=/index.js

In documentation for the mapPropsToFields function it is written:
Please note that the form fields will become controlled components. Properties like errors will not be automatically mapped and need to be manually passed in.

The above example uses the mapPropsToFields function.
Please explain why form field validation works. (how errors manually passed in)