When a unknown variable is narrowed to a specific type, assigning another value with the same type resets the first back to unknown

[AlCalzone]

Bug Report

🔎 Search Terms

unknown, number, assign

🕗 Version & Regression Information

On the playground this behavior goes back to at least 3.3.3333

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about unknown
• I was unable to test this on prior versions because there is no earlier version on the playground

⏯ Playground Link

Playground link with relevant code

💻 Code

declare function takesNumber(value: number): void;

function test(value: unknown) {
  if (typeof value !== "number") return;
  takesNumber(value); // ok
  value = 1; // assign the same type!
  takesNumber(value); // error (value is unknown, although we narrowed it to number before)
}

🙁 Actual behavior

value is unknown after the assignment

🙂 Expected behavior

value should still be number

[whzx5byb]

Related: #27706 (comment), #16976 (comment)

[AlCalzone]

Huh, seems like this is an exact duplicate of #27706. Man, unknown is really still awkward.