[BUG] Sequence Expression in umi3 cause error.

[Mistrain-y-y]

Recently, I'm using babel-plugin-istanbul, which will generate code with Sequence Expression (Comma Operator). And encountered a problem (I simplify it):

import {Form} from 'antd';

let a = 1;
const b = (a++, Form);// use Comma Operator

I think Form should be like these:

But I get these code:

Error:

I found the same issue in babel-plugin-import, but I don't know how to fix it when I use umi3. I use umi@3.5.41.
feat: conditional expression supports comma operator #593

[fz6m]

umi 3 不维护了，建议升级到 umi 4 。

[Mistrain-y-y]

But is there any solution for this problem?