Missing types from PageServerParentData if parent layout load returns void

[eltigerchino]

Describe the bug

If a layout load function returns void at any part of the function, the types for parent() in child load functions will be broken.

Reproduction

https://stackblitz.com/github/s3812497/sveltekit-load-types-bug?file=src%2Froutes%2Fabout%2F%2Bpage.server.ts

Expected:
src/routes/about/+page.server.ts has types when retrieving data from the parent load function src/routes/+layout.server.ts

Actual:
src/routes/about/+page.server.ts shows an error stating the property does not exist when retrieving the data from parent()
e.g.
Property 'b' does not exist on type 'PageServerParentData'.(2339)

Logs

No response

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 16.14.2 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.84 
    @sveltejs/kit: next => 1.0.0-next.525 
    svelte: ^3.44.0 => 3.52.0 
    vite: ^3.1.0 => 3.2.0

Severity

annoyance

Additional Information

A workaround is to avoid returning void in the parent load function and return an empty object instead.