Question: Strange behavior on generic functions return `Result`

[ForkKILLET]

const raise = <E>(err: E): Result<never, E> => Result.error(err)

Error:

Type 'Error<E>' is not assignable to type 'Error$1<E>'.

Version: [email protected]

[gyg-persien]

Same here but with Result.Ok(res) in a generic function: Type 'Ok<T>' is not assignable to type 'Result<T, Error>'. This keeps us from upgrading to even 3.3.0 from 3.1.1, where everything is fine.

[everweij]

Thanks @ForkKILLET and @gyg-persien for raising this issue!

I have a repro here

Result.Error<E> should equal Result<never, E>, so I need to do some digging to see what's going on here.

[everweij]

I've worked on a fix: https://github.com/everweij/typescript-result/releases/tag/v3.5.3-beta.1

When you have time, please check whether this beta release fixes the issues you are having and let me know.

[vdawg-git]

I tried out v3.5.3-beta.1 , but I still get those errors where Result.ok(<T>) is not assignable to Result<T, unknown>.

I am on Typescript ^5.9.2.

And thank you for this awesome library! :)

      Type '{ data: Result.Ok<T>; isFetching: boolean; isLoading: false; }' is not assignable to type '{ data: Result<T, unknown>; isFetching: boolean; isLoading: false; }'.
        Types of property 'data' are incompatible.
          Type 'Ok<T>' is not assignable to type 'Result<T, unknown>'.
            Type 'Result$1<T, never>' is not assignable to type 'Ok<T>'.

[everweij]

Hey @vdawg-git, thanks for checking the beta release. Could you please share some code (that triggers the error message you've shared earlier) so I can identify the error and debug it locally? Feel free to use the playground (still runs v3.5.2). Thanks!