🔎 Search Terms

widening return unique symbol

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play?ts=5.3.0-dev.20230814&ssl=6&ssc=2&pln=1&pc=1#code/KYDwDg9gTgLgBAYwgOwM7xsdcC8cDKAngLYBGEANgBQCUAUHaJLHAGYCuyCMAlim8lpwA3nTjjEKbAEMKPaagBccGITDAIrFVnh5M6ANxiJUYDHZRkcWfNR0AvkA

💻 Code

export const test = Symbol()

export function fn() {
    const alias: typeof test = test;
    return alias
}

🙁 Actual behavior

this declaration file is emitted:

export declare const test: unique symbol;
export declare function fn(): symbol;

🙂 Expected behavior

this declaration file to be emitted:

export declare const test: unique symbol;
export declare function fn(): typeof test;

Additional information

getWidenedLiteralLikeTypeForContextualReturnTypeIfNeeded calls getWidenedLiteralLikeTypeForContextualType and that calls getWidenedUniqueESSymbolType when there is no contextual type provided.

some issues that are (partially~) related:
#32242
#35896 (comment)
#36876