optional component props with default value typescript regression

[DanConwayDev]

Describe the bug

In svelte 4 I could do this without any typescript errors:

// Component.svelte
<script lang="ts">
export let name: 'alice'|'bob' = 'alice';
</script>
<h1>{name} is {name.length} letters!</h1>

// +page.svelte
<Component />

In svelte 5 I do this:

// Component.svelte
<script lang="ts">
  let { name ='alice' }: {name: 'alice'|'bob'}  = $props();
</script>
<h1>{name} is {name.length} letters!</h1>

// +page.svelte
<Component />

but get a type error on +page.svelte:

Type '{ name: "alice"|"bob" }' is missing the following properties from type '$$ComponentProps': name

So i must do this to make the compiler happy:

// Component.svelte
<script lang="ts">
  let { name ='alice' }: {name?: 'alice'|'bob'}  = $props();
</script>
...
<h1>{name} is {name ? name.length | 0} letters!</h1>

// +page.svelte
<Component />

Am I missing something?

Reproduction

https://svelte.dev/playground/a560df440aff4b7db0f45c20bfcfc154?version=5.17.3

Logs

No response

System Info

System:
    OS: Linux 6.6 Debian GNU/Linux 12 (bookworm) 12 (bookworm)
    CPU: (3) x64 12th Gen Intel(R) Core(TM) i7-1260P
    Memory: 26.06 GB / 29.99 GB
    Container: Yes
    Shell: 5.2.15 - /bin/bash
  Binaries:
    Node: 22.11.0 - /nix/store/fkyp1bm5gll9adnfcj92snyym524mdrj-nodejs-22.11.0/bin/node
    Yarn: 1.22.22 - ~/.nix-profile/bin/yarn
    npm: 10.9.0 - /nix/store/fkyp1bm5gll9adnfcj92snyym524mdrj-nodejs-22.11.0/bin/npm
    pnpm: 9.15.3 - /nix/store/p7r1k66dzs1qpkas0jx5v20asih9y37q-pnpm-9.15.3/bin/pnpm
  Browsers:
    Brave Browser: 131.1.73.104
  npmPackages:
    svelte: ^5.0.0 => 5.14.4

Severity

annoyance

[DanConwayDev]

never mind. there was an issue with my setup.