[Bug]: Documentation is not generated when using React.FC in TypeScript

[kyletsang]

Describe the bug

When using React.FC to specify the component type, the documentation will not be generated.

Here is minimal repro of a component:

export interface AppProps {
  /**
   * A string paramter.
   */
  param1: string

  /**
   * A number parameter.
   */
  param2: number
}

/**
 * This is a component.
 */
const App: React.FC<AppProps> = ({ param1, param2 }) => {
  return (
    <div>
      <div>Param 1: {param1}</div>
      <div>Param 2: {param2}</div>
    </div>
  )
}

export default App

If I use the above snippet and substitute the declaration using the following, it works properly

const App = ({ param1, param2 }: AppProps) => {

This used to work in the earlier betas (Beta 33 I think?), but stopped working at some point after that. When I get a chance, I'll try to find the earliest version in which this started occurring.

To Reproduce

https://github.com/kyletsang/storybook-ts-docs-repro

System

Environment Info:

  System:
    OS: macOS 13.2.1
    CPU: (8) x64 Intel(R) Core(TM) i7-1068NG7 CPU @ 2.30GHz
  Binaries:
    Node: 16.19.0 - ~/.nvm/versions/node/v16.19.0/bin/node
    Yarn: 1.22.15 - /usr/local/bin/yarn
    npm: 8.19.4
  Browsers:
    Chrome: 111.0.5563.146
    Edge: 111.0.1661.62
    Firefox: 109.0.1
    Safari: 16.3

Additional context

No response

[nuxcodes]

Similar to #21801. React.forwardRef also breaks ArgTypes type inference.

The type inference works once I remove React.FC, and the control becomes radio buttons for union types. But if the union type includes both null and undefined, the control would remain text controls.

[kasperpeulen]

Somehow using a named export fixes this issue.
Even though that the component is still imported as a default export...
cc @shilman

[shilman]

Jeepers creepers!! I just released https://github.com/storybookjs/storybook/releases/tag/v7.1.0-alpha.1 containing PR #22024 that references this issue. Upgrade today to the @future NPM tag to try it out!

npx sb@next upgrade --tag future

[shilman]

Yay!! I just released https://github.com/storybookjs/storybook/releases/tag/v7.0.3 containing PR #22024 that references this issue. Upgrade today to the @latest NPM tag to try it out!

npx sb@latest upgrade