Inconsistent enum literal types

[Andarist]

🔎 Search Terms

return type inference enum union literal fresh regular

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.8.0-dev.20250216#code/KYOwrgtgBAolDeUCCAaKAhKBfAUDgLgJ4AOwGA9gB4A8AKgHxQC8COUUA5sPgFxQAUASmaNaAbjZQAztz78AbgEMANmGB9awpo3nkAlgBMJWCTgPAAxssUAnMgDMwIC-j3kQUAEZU69BSrUNQT50HwZTC3cpfC8QAEZmLyp+AAZBMSgAekyKGnAIT2AbehxIkGjYgCYQn3zC4sTvSlT0rJyAeQBrPDKKwoSWJv4YADokVuzc6hgS3pjC6qmZxuTR8YzJmBsbchs0JumxxhByGMUpKT0OEEVPZTJ8ciWSoA

💻 Code

enum E { A, B }

type Box<T> = {
  get: () => T;
  set: (value: T) => void;
};

declare function box<T>(value: T): Box<T>;

const bn1 = box(0); // Box<number>
const bn2: Box<number> = box(0); // Ok

const be1 = box(E.A); // Box<E>
const be2: Box<E> = box(E.A); // Error, box<E.A> not assignable to Box<E>

🙁 Actual behavior

be2 errors

🙂 Expected behavior

be2 shouldn't error

Additional information about the issue

This is an enum-based variant of #48363 . As such it relates to the open #59754 too