Aliased optional chain calls don't narrow like their inline equivalents

🔎 Search Terms

aliased conditions control flow analysis cfa optional chain call

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.6.0-dev.20240704#code/GYVwdgxgLglg9mABAJwKYGc4BsBuqCMAFDACYBci6UyMYA5ogD6LgmrC2okCUiA3gChEiCAiqIY6AEKssXRAF4JJAPwA6WhCwg26QgCIA+gCNZXfdwDcQicETFpZnvxvDRYcVWQUvtBktJrYQBfAVCBUEhYBBQMbDwAJmJySmo-JhYwNg4wLl5BYRg7ZPVNbV0DEycLfNcRMShU7yb0gJIgxFDgoA

💻 Code

function resolve1(id: string | undefined) {
  const isBundled = id?.includes("_bundled");
  if (isBundled) {
    const str: string = id; // error
  }
}

function resolve2(id: string | undefined) {
  if (id?.includes("_bundled")) {
    const str: string = id; // ok
  }
}

🙁 Actual behavior

resolve1 errors within the if block

🙂 Expected behavior

I'd expect it to be OK. Just like resolve2 is OK with it here - the condition is exactly the same and TS supports Control Flow Analysis of Aliased Conditions and Discriminant since 4.4

Additional information about the issue

No response

Comienza con la reproducción enlazada en TypeScript Playground y compara resolve1 con resolve2. Después, sigue el análisis de control de flujo para las condiciones con alias y las llamadas con optional chaining. Añade o actualiza una prueba de regresión que muestre que la condición con alias estrecha id igual que la condición inline, y verifica que ambas asignaciones de string tengan éxito.