Using forward and partialCheck like the password compare example results in multiple type errors

[matthew-dean]

Reproduction example here

const FormSchema = pipe(
  object({
    password: pipe(string(), minLength(6), maxLength(18)),
    confirmPassword: string(),
  }),
  forward(
    partialCheck(
      [['password'], ['confirmPassword']],
      (input) => input.password === input.confirmPassword,
      'The two passwords do not match.'
    ),
    ['confirmPassword']
  )
);

I don't get errors in TypeScript language services, but the reproduction example fails to compile in tsc / vue-tsc.

The two errors are:

• error TS2589: Type instantiation is excessively deep and possibly infinite.
• error TS2339: Property 'confirmPassword' does not exist on type '{ password: string; }'

[matthew-dean]

Workaround:

I got this working with this workaround (which also compiled much, much faster):

const FormSchema = pipe(
  object({
    password: pipe(string(), minLength(6), maxLength(18)),
    confirmPassword: string()
  }),
  forward<{
    password: string
    confirmPassword: string
  }, PartialCheckIssue<{
    password: string
    confirmPassword: string
  }>>(
    partialCheck(
      [['password'], ['confirmPassword']],
      input => input.password === input.confirmPassword,
      'The two passwords do not match.'
    ),
    ['confirmPassword']
  )
)

So it seems like type-inference from partialCheck + type inference into forward is just too complex with this simple example.

[fabian-hiller]

Not sure there is anything we can do about this. Having the path argument of partialCheck and forward typesafe is a great DX, but also results in a complex TS type that can cause such problems.