Get another function's parameter types for use in another function's rest parameter

[STofone]

🔎 Search Terms

Rest parameter

🕗 Version & Regression Information

TypeScript Version 5.5.2

⏯ Playground Link

No response

💻 Code

type AnyFunction = (...args: any[]) => any;
interface TestService {
  [key: string]: {
    [key: string]: AnyFunction;
  };
}
declare function f<S extends keyof TestService , F extends keyof TestService[S], A extends Parameters<TestService[S][F]>>(k1: S, k2: F, ...args: A): void;

🙁 Actual behavior

❌report at A : Rest parameter must be an array type or a generic with array constraint

🙂 Expected behavior

It can infer another function's params tuple as a rest param type

Additional information about the issue

#29919 seems similar
found in stackoverflow https://stackoverflow.com/questions/76772628/get-another-functions-parameter-types-for-use-in-another-functions-rest-par

[MartinJohns]

You forgot to fill out the issue template completely.

The code does not show any error in the playground.

[STofone]

same code in idea

I tried in ts playground, it works fine.

ts playground
may be is a problem of idea

[STofone]

Weird difference between each way of function definition inside object

[MartinJohns]

Weird difference between each way of function definition inside object

Properties and methods have different variance when strictFunctionTypes is enabled. And functions and lambdas have different this context.

[STofone]

Properties and methods

playground
I understand the different this context, but it seems has no difference of input param types.
And it works fine in playground.