Microsoft/TypeScript
View on GitHubUnable to resolve generic type when using an overloaded function as parameter
Open
#52,305 opened on Jan 19, 2023
BugDomain: check: Type InferenceHelp Wanted
Description
Bug Report
🔎 Search Terms
overload parameter function
🕗 Version & Regression Information
Using the playground, the code works when I choose version 3.3.3. After that version, the problem comes up.
💻 Code
type SpecialType<T> = () => void & { value: T };
function specialFunction<T>(): SpecialType<T>;
function specialFunction<T>(source: Record<string, T>): Record<string, T>;
function specialFunction<T>(source?: Record<string, T>): SpecialType<T> | Record<string, T> {
return source as any;
}
const otherFunction = <K extends keyof T, T>(source: Record<string, T>, property: K): Record<string, T[K]> => ({ source, property }) as any;
const obj: Record<string, { label: string }> = { value: { label: 'hello world' } };
const defined = specialFunction(obj);
const working = otherFunction(defined, 'label');
const nonworking = otherFunction(specialFunction(obj), 'label');
const alsoworking = otherFunction(specialFunction<{ label: string }>(obj), 'label');
🙁 Actual behavior
The non-inlined call chain works and label is recognized as a property name. The inlined call as a parameter states, that the second parameter type is never(instead of keyof T).
🙂 Expected behavior
No different type resolution regardless of the call type.