fix: transform `$bindable` after `await` expressions (#17066)

Fixes #17064

.changeset/hot-crews-notice.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: transform `$bindable` after `await` expressions

packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js

@@ -55,7 +55,7 @@ export function transform_body(instance_body, runner, transform) {
 
 				if (visited.declarations.length === 1) {
 					return b.thunk(
-						b.assignment('=', s.node.id, visited.declarations[0].init ?? b.void0),
+						b.assignment('=', visited.declarations[0].id, visited.declarations[0].init ?? b.void0),
 						s.has_await
 					);
 				}

packages/svelte/tests/runtime-runes/samples/async-bindable-prop/Child.svelte

@@ -0,0 +1,8 @@
+<script>
+	await Promise.resolve();
+	let { value = $bindable("test") } = $props();
+</script>
+
+<button onclick={() => value = 'updated'}>update</button>
+{value}
+

packages/svelte/tests/runtime-runes/samples/async-bindable-prop/_config.js

@@ -0,0 +1,35 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['async-server', 'client', 'hydrate'],
+	ssrHtml: `
+		<button>update</button> initial <p>initial</p>
+	`,
+
+	async test({ assert, target }) {
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>update</button>
+				initial
+				<p>initial</p>
+			`
+		);
+
+		const button = target.querySelector('button');
+		button?.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>update</button>
+				updated
+				<p>updated</p>
+			`
+		);
+	}
+});

packages/svelte/tests/runtime-runes/samples/async-bindable-prop/main.svelte

@@ -0,0 +1,9 @@
+<script>
+	import Child from './Child.svelte';
+
+	let value = $state('initial');
+</script>
+
+<Child bind:value />
+<p>{value}</p>
+