Function that returns never doesn't work when placed inside an object

[LeoAso]

Bug Report

🔎 Search Terms

never, throw, error, unreachable

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about functions returning never

⏯ Playground Link

Playground link with relevant code

💻 Code

function panic(): never {
  throw new Error('Oh no!');
}

export const errors = {
  panic(): never { throw new Error('Oh no!'); },
  // also tried these
  // panic: (): never => { throw new Error('Oh no!'); },
  // panic,
}
// also tried these
//} as const;
//} satisfies Record<string, (() => never)>;

function maybeGetString(): string | null {
  return "I'm a string!";
}

function test() {
  const a = maybeGetString();
  if (!a) errors.panic();
  // if (!a) panic(); // the error goes away if you use this instead

  const b: string = a;
  console.log(b);
}

🙁 Actual behavior

A function returning never is being treated differently when it is called from inside an object i.e. panic vs errors.panic. This is despite the fact that they both resolve to the same type () => never.

🙂 Expected behavior

The function should work the same way regardless of how it is called. It should work the same as a throw statement, so that in the code snippet above, the type of a is narrowed from string | never to string, and there should be no error on the statement const b: string = a

[MartinJohns]

Duplicate of #36753 and many many others. It's working as intended and documented.

[nmain]

As detailed above, you'd have to remove the inference on errors to fix this.

export const errors: { panic: () => never } = {
  panic(): never { throw new Error('Oh no!'); },
}