Is it possible to write generic type level map function for tuples?

Question

I want to do this

const tuple = ["foo", "bar"] as const

const convert = <T>(x: T): {item: T} => ({item: x})

const convertedTuple: [{item: "foo"}, {item: "bar"}] = tupleMap(tuple, convert)

I have tried this

type TupleMap<T extends readonly any[], Fn extends (item: any) => any> 
  = T extends readonly [infer Head, ...infer Tail]
      ? (Fn extends (item: Head) => infer R
        ? [R, ...TupleMap<Tail, Fn>]
        : never)
      : []

function tupleMap<T extends readonly any[], 
  Fn extends (item: any) => any>(a: T, fn: Fn): TupleMap<T, Fn> {
  return a.map(fn) as any
}

But convertedTuple type is inferenced as [{item: unknown}, {item: unknown}] and I am not sure why.