`{ params } = $props()` doesn't work

[craig-jennings]

Describe the bug

#13999 added better typing for params that are used when destructuring the $props rune, however it appears this doesn't actually work. I get undefined when I $inspect params and the server 500s when I try to access a param.

Reproduction

1. sv create test
   • Choose minimal option
   • Choose typescript option
   • Skip add-ons
   • Use pnpm
2. Create a src/routes/[x]/+page.svelte file with the following content

<script>
	let { params } = $props();
</script>

<p>x: {params.x}</p>

3. Run pnpm dev
4. Navigate to http://localhost:5173/test
5. Notice the server gives a 500 error TypeError: Cannot read properties of undefined (reading 'x')

Logs

System Info

System:
    OS: Linux 6.6 Ubuntu 24.04.2 LTS 24.04.2 LTS (Noble Numbat)
    CPU: (12) x64 AMD Ryzen 5 5600X 6-Core Processor
    Memory: 22.29 GB / 31.31 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 22.17.1 - ~/.nvm/versions/node/v22.17.1/bin/node
    Yarn: 1.22.22 - ~/.nvm/versions/node/v22.17.1/bin/yarn
    npm: 10.9.2 - ~/.nvm/versions/node/v22.17.1/bin/npm
    pnpm: 10.13.1 - ~/.nvm/versions/node/v22.17.1/bin/pnpm
  npmPackages:
    @sveltejs/adapter-auto: ^6.0.0 => 6.0.1
    @sveltejs/kit: ^2.22.0 => 2.25.0
    @sveltejs/vite-plugin-svelte: ^6.0.0 => 6.1.0
    svelte: ^5.0.0 => 5.36.7
    vite: ^7.0.4 => 7.0.5

Severity

serious, but I can work around it

Additional Information

No response