Describe the bug

This is a common hack to use a comma to declare generics without default or extends in TSX file. It's seems that some part of the build chain (in dev mode) drop the comma, making the file invalid.

Reproduction

https://github.com/ArnaudBarre/vite-generic-bug

Equivalent to yarn create @vitejs/app --template react-ts + update main.tsx to:

const App = <T,>(props: {value: T}) => {
    return <div>Hello {typeof props.value}</div>
}

ReactDOM.render(
  <React.StrictMode>
    <App value="string" />
  </React.StrictMode>,
  document.getElementById('root')
)

System Info

• vite version: 2.0.4 (esbuild 0.8.53)
• Operating System: Mac
• Node version: 14.13.1
• Package manager: yarn 1.22.10