Describe the bug

I got red squigly line when putting async in onServerValidate. But it run normally in runtime.
Type Promise <string | undefined> is not assignable to type ValidationError

Your minimal, reproducible example

https://www.typescriptlang.org/play/?#code/PTAEHUFMBsGMHsC2lQBd5oBYoCoE8AHSAZVgCcBLA1UABWgEM8BzM AVwDsATAGiwoBnUENANQAd0gAjQRVSQAUCEmYKsTKGYUAbpGF4OY0BoadYKdJMoL gzAzIoz3UNEiPOofEVKVqAHSKymAAmkYI7NCuqGqcANag8ABmIjQUXrFOKBJMggBcISGgoAC0oACCbvCwDKgU8JkY7p7ehCTkVDQS2E6gnPCxGcwmZqDSTgzxxWWVoASMFmgYkAAeRJTInN3ymj4d-jSCeNsMq-wuoPaOltigAKoASgAywhK7SbGQZIIz5VWCFzSeCrZagNYbChbHaxUDcCjJZLfSDbExIAgUdxkUBIursJzCFJtXydaiKKEEeBkGgAb1A7EEkAAYlTEKAAL44thsgBEAAFUGZBILYPFgJNYKhSslWTyANzBBCcYU41mgAC89MZLLIiAAFDTFCUStxIMkGFFUAA1BjQdiQfKgQ3Gl39BjIR08nlG43s3jBF2NYjfPRkG3QCjcOoOsTHcygA2gHS2 0cgCUGoAfE6fa7QCoACIYCpx2CgYNkUOgcORuoNTi5jmKdlp4IqHDNDxkLyIKnOYHsGhfNxmZjsBjMSD8WAR0ViYF6EReHkAUVW7oW h5SWxPPADlQAHJhAA5SASHlBFQAeS ZHejP4k6OgupkFc0jwoCcvZ0wyw goAgiDQsIlzDhIVLRCIBgcNiCxMKwHA8EEihAA

Steps to reproduce

1. Put async in the onServerValidate
2. Got Type error

Expected behavior

No Type Error.

How often does this bug happen?

Every time

Screenshots or Videos

Platform

• OS: Windows
• Browser: OperaGX

TanStack Form adapter

react-form

TanStack Form version

v0.20.2

TypeScript version

v5.4.2

Additional context

No response