unstable_data with LoaderFunction using unstable_singleFetch breaks type inference

[0t4u]

Reproduction

https://stackblitz.com/edit/remix-run-remix-qkcaqv?file=app%2Froot.tsx%3AL44

System Info

System:
    OS: Windows 11 10.0.22631
    CPU: (32) x64 Intel(R) Core(TM) i9-14900HX
    Memory: 5.18 GB / 31.73 GB
Binaries:
    Node: 20.17.0 - ~\AppData\Local\Volta\tools\image\node\20.17.0\node.EXE
    npm: 10.8.2 - ~\AppData\Local\Volta\tools\image\node\20.17.0\npm.CMD
    pnpm: 9.7.1 - C:\Program Files\Volta\pnpm.EXE
    bun: 1.1.20 - ~\.bun\bin\bun.EXE
Browsers:
    Edge: Chromium (127.0.2651.74)
    Internet Explorer: 11.0.22621.3527
npmPackages:
    @remix-run/dev: ^2.12.0 => 2.12.0
    @remix-run/node: ^2.12.0 => 2.12.0
    @remix-run/react: ^2.12.0 => 2.12.0
    @remix-run/serve: ^2.12.0 => 2.12.0
    vite: ^5.4.3 => 5.4.3

Used Package Manager

npm

Expected Behavior

Types of data returned from LoaderFunction should be inferred correctly.

Actual Behavior

Types are being incorrectly inferred by useLoaderData<typeof loader>(), resulting in {}.

[brophdawg11]

This looks like the same issue as #7700. By using const loader: LoaderFunction you are telling TS the return type is the underlying looser type for any loader and prevents TS from inferring the type this specific loader returns.

Using const loader = (args: LoaderFunctionArgs) allows TS to properly infer as does satisfies LoaderFunction.

https://stackblitz.com/edit/remix-run-remix-jfrnfq?file=app%2Froot.tsx