JSX element type 'FormItem' is not a constructor function for JSX elements.

react 16.13.1
@types/react 16.9.34

升级迁移 兼容V3时 Form & FormItem报错

// tsconfig
{
"compilerOptions": {
"baseUrl": "src",
"target": "es5",
"lib": [
"dom",
"dom.iterable",
"esnext"
],
"allowJs": true,
"skipLibCheck": true,
"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
"strict": true,
"forceConsistentCasingInFileNames": true,
"module": "esnext",
"moduleResolution": "node",
"resolveJsonModule": true,
"isolatedModules": true,
"noEmit": true,
"jsx": "react",
"experimentalDecorators": true,
"noImplicitThis": false
},
"include": [
"src"
],
"extends": "./paths.json"
}

{form.getFieldDecorator(`departmentIds[_${item}]`, {
rules: required === false ? [] : [{ required: true, message: '请选择部门' }],
initialValue: index < (departmentList || []).length ? initDepartmentObj[item] : undefined
})(
label.join(' - ')}
getPopupContainer={(triggerNode:{parentNode:React.ReactNode}) => triggerNode.parentNode}
{...rst}
/>
)}

The issue provides a tsconfig and a LegacyForm.Item usage example, but names no source file or test. Start by reproducing the JSX type error with React 16.13.1 and @types/react 16.9.34, then trace the Form and FormItem compatibility path. Done means the migration example type-checks without the constructor-function error.

Written by the indexing model from the issue text.