Nested inference fails if function is called inline

Bug Report

🔎 Search Terms

Nested inference, function call

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about nested function call inference

⏯ Playground Link

With libraries
Minimal reproduction

💻 Code

type NoInfer<T> = [T][T extends any ? 0 : never]

type ErrorFn = (error: unknown) => void

declare const genericFn: <T>(args: {
  parser: (p: unknown, errorFn: ErrorFn) => T
  handler: (data: { body: NoInfer<T> }) => unknown
}) => T

declare const createParser: <T>(arg: T) => (p: unknown, errorFn: ErrorFn) => NoInfer<T>;

genericFn({
  parser: createParser(1 as const),
  handler: ({ body: _ }) => {
    //         ^?
    // unknown, should be 1
  }
})

🙁 Actual behavior

Handler body is not inferred, becomes default of unknown.

🙂 Expected behavior

Handler body should be inferred from parser, and be 1.

Inizia con la riproduzione minima collegata in TypeScript Playground, quindi confrontala con la versione che usa librerie. Traccia come la chiamata inline a createParser contribuisce all’inferenza dei generics e verifica il tipo del corpo dell'handler. Il lavoro è completato quando il caso riprodotto inferisce body come 1 anziché unknown.