Generics attribute with const modifier on script tag do not type check props

[Nick-Mazuk]

Describe the bug

When you have a generics attribute on a script tag (introduced in #2020), it turns off type checking anytime that generic is used as the type of a prop.

Reproduction

Let's say you have a component items.svelte

<script lang="ts" generics="const T extends readonly string[]">
    export let items: T
    export let currentItem: T[number]
</script>

You can now use this component with any nonsense props. For instance, all of the following pass type checking when none of them should:

<script lang='ts'>
    import Items from './items.svelte'
</script>

<!-- here currentItem is invalid -->
<Items items="{['item 1', 'item 2']}" currentItem="foobar" />
<Items items="{['item 1', 'item 2']}" currentItem="{3}" />
<Items items="{['item 1', 'item 2']}" currentItem="{{ foo: 'bar' }}" />

<!-- here items is invalid -->
<Items items="{['item 1', 'item 2', { foo: 'bar' }]}" currentItem="item 1" />
<Items items="{{ foo: 'bar' }}" currentItem="item 1" />
<Items items="foo bar" currentItem="item 1" />

Expected behaviour

None of the above reproduction cases should type check.

However the following case should type check:

<Items items="{['item 1', 'item 2']}" currentItem="item 2" />

Here's the equivalent TypeScript code in the TypeScript playground.

System Info

• OS: macOS
• IDE: VS Code (also reproduced using svelte-check CLI directly)

Relevant packages:

• svelte: 4.0.4
• svelte-check: 3.4.4
• typescript 5.1.6

Which package is the issue about?

svelte-check

Additional Information, eg. Screenshots

No response