When using keyof typeof, downstream code inference breaks in unexpected ways #23649

export function Set<K extends string>(...keys: K[]): Record<K, true | undefined> {
  const result = {} as Record<K, true | undefined>
  keys.forEach(key => result[key] = true)
  return result
}

export function keys<K extends string, V>(obj: Record<K, V>): K[] {
  return Object.keys(obj) as K[]
}

type Obj = { code: LangCode }


/* No duplication - Derived */
const langCodeSet = Set('fr', 'en', 'es', 'it', 'nl')
export type LangCode = keyof typeof langCodeSet
export const langCodes = keys(langCodeSet)

// Does not compile (???)
const arr: Obj[] = langCodes.map(code => ({ code }))



/* Duplication */
export type LangCode2 = 'fr' | 'en' | 'es' | 'it' | 'nl'
export const langCodes2: LangCode2[] = ['fr', 'en', 'es', 'it', 'nl']

// Compiles
const arr2: Obj[] = langCodes2.map(code => ({ code }))