Reactive, destructured declarations aren't recognised by TypeScript in certain combinations

[sxxov]

Describe the bug

When writing reactive, destructured declarations (using the $: directive), with certain combinations of renames & default initialisers, TypeScript would be confused into thinking it's a variable assignment expression instead of a declaration statement.

Reproduction

<script lang="ts">
	// 1. OK  → $: ({ a = 1, c: d = 2 } = { a: 0, c: 0 });
	// 2. OK  → $: ({ a: b = 1, c: d } = { a: 0, c: 0 });
	// 3. OK  → $: ({ a: b = 1, c = 2 } = { a: 0, c: 0 });
	// 4. OK  → $: ({ a: b = 1, c: d, e: f = 2 } = { a: 0, c: 0, e: 0 });
	// 5. NOK → $: ({ a: b = 1 } = { a: 0 });
	// 6. NOK → $: ({ a: b = 1, c: d = 2 } = { a: 0, c: 0 });

	// Using no. 5 as a runnable example that fails:
	$: ({ a: b = 1 } = { a: 0 });
	//       ^ Cannot find name 'b'. ts(2304)
</script>

Expected behaviour

<script lang="ts">
	// 1. OK  → $: ({ a = 1, c: d = 2 } = { a: 0, c: 0 });
	// 2. OK  → $: ({ a: b = 1, c: d } = { a: 0, c: 0 });
	// 3. OK  → $: ({ a: b = 1, c = 2 } = { a: 0, c: 0 });
	// 4. OK  → $: ({ a: b = 1, c: d, e: f = 2 } = { a: 0, c: 0, e: 0 });
	// 5. OK  → $: ({ a: b = 1 } = { a: 0 });
	// 6. OK  → $: ({ a: b = 1, c: d = 2 } = { a: 0, c: 0 });

	// Using no. 5 as a runnable example that shouldn't fail:
	$: ({ a: b = 1 } = { a: 0 });
	//       ^ let b: number
</script>

System Info

• OS: Windows 11 21H2
• IDE: VSCode 1.70.1

Which package is the issue about?

svelte-language-server

Additional Information, eg. Screenshots