We did not change anything in transform. However, we have made changes to the validation functions such as minValue. I will check if this causes the problem and if there is a solution. What you can do alternatively until this is fixed is to pass a schema with a pipe instead of just a pipe as the third argument.

const n = parse(
  transform(string(), (input) => parseInt(input, 10), number([minValue(0)])),
  '1'
);

If you stick with the generics as a workaround, I recommend changing the second generic to the first argument of minValue:

const n = parse(
  transform(string(), (input) => parseInt(input, 10), [minValue<number, 0>(0)]),
  "1",
);

I can use the schema workaround for now, it helps, thanks!

Unfortunately, I haven't found a solution other than the workaround, and I'm not sure there is one. The problem is that TypeScript no longer resolves the types correctly since the internal change from a function to an object. I'll take another look at the problem in the next few weeks.

Thanks for the effort. I'm totally fine with the workaround. But IMO if using pipes as the third argument of transform is an allowed usage maybe this should be addressed somewhere if not here? Is this an issue that should be raised and fixed in TypeScript? Or is there already one where I can track?

Yes, that is why I did not close this issue. I think it is not a TypeScript bug, just a different behavior than expected on our end. I will investigate this again in the coming weeks. If there is no solution, we could simply not allow a pipe as a third argument.

Again, thanks for your effort and appreciate your time! @fabian-hiller

This should no longer be a problem with the latest version.