Iterator return type not constraining typed arrays literals

[oguimbal]

Bug Report

🕗 Version & Regression Information

It has always been there. (tested with every Typescript version available in the playground since the support or typing for iterator return types)

⏯ Playground Link

👉 Reproduction link in playground

💻 Code

export type It = Iterator<[string, number], [string, number]>;

function *it(): It {
    yield ['', 0]; // this works ✔️
    return ['', 0]; // this fails ❌
}

🙁 Actual behavior

The return statement does not constraint the array literal to the right type. Instead, it takes its... I dont know how to put it... its "natural" type ?

🙂 Expected behavior

Both yield & return statements should compile.

👉 Workaround: Force the array to be correctly typed via return ['', 0] as const.

[rbuckton]

This looks to have been fixed in TypeScript 4.8 as a result of #49736.