setQueryData updater loses discriminated-union fields when spreading inferred NoInfer data

[ryoid]

Describe the bug

With @tanstack/react-query 5.104.0, an updater passed to setQueryData(queryOptions(...).queryKey, updater) fails when it narrows a discriminated union and spreads the narrowed value. The tagged key supplies the correct data type, but the inferred updater parameter is wrapped in NoInfer<Data>. The spread loses the variant-specific fields.

Explicitly annotating the updater parameter as Data | undefined makes the same update compile. This appears related to #11018, but affects the QueryClient cache updater rather than the useQuery result.

Minimal reproduction

import { QueryClient, queryOptions } from '@tanstack/react-query'

type Data =
  | { kind: 'a'; value: number; requiredA: number }
  | { kind: 'b'; value: number; requiredB: number }

const query = queryOptions({
  queryKey: ['example'],
  queryFn: async (): Promise<Data> => ({ kind: 'a', value: 1, requiredA: 1 }),
})
const client = new QueryClient()

// Correctly inferred from the tagged key.
const inferred: Data | undefined = client.getQueryData(query.queryKey)

// Fails with TS2345.
client.setQueryData(query.queryKey, (prev) => {
  if (!prev || prev.kind !== 'a') return prev
  return { ...prev, value: prev.value + 1 }
})

// The same update passes with an explicit parameter annotation.
client.setQueryData(query.queryKey, (prev: Data | undefined) => {
  if (!prev || prev.kind !== 'a') return prev
  return { ...prev, value: prev.value + 1 }
})

Steps to reproduce

Typecheck the example with TypeScript 5.8.3:

tsc --noEmit --strict --skipLibCheck --target es2023 --moduleResolution bundler --module esnext repro.ts

The unannotated updater fails with a return type containing { value: number; kind: "a" | "b" }, missing requiredA and requiredB. The annotated updater compiles.

Expected behavior

After prev.kind !== 'a' returns, spreading prev should preserve kind: 'a' and requiredA. The documented query-options key inference should allow this update without repeating the data type on the parameter.

Versions

• @tanstack/react-query: 5.104.0
• @tanstack/query-core: 5.104.0
• TypeScript: 5.8.3
• Platform: macOS; compile-time only

Additional context

The reproducer uses no application-specific wrappers, key registration, or casts. The reverse-inference guard should remain intact; this report is about preserving normal union narrowing and spread behavior while retaining that guard.