fix, add test

Author: Rich-Harris

packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js

@@ -298,18 +298,13 @@ export function EachBlock(node, context) {
 	let key_function = b.id('$.index');
 
 	if (node.metadata.keyed) {
-		const pattern = node.context;
 		const expression = /** @type {Expression} */ (
 			context.visit(/** @type {Expression} */ (node.key), key_state)
 		);
-		/** @type {Pattern[]} */
-		const args = [];
-		if (pattern) {
-			args.push(pattern);
-		}
-		if (key_uses_index) {
-			args.push(index);
-		}
+
+		const args = [node.context ?? b.id('$$')];
+		if (key_uses_index) args.push(index);
+
 		key_function = b.arrow(args, expression);
 	}
 

packages/svelte/tests/runtime-runes/samples/each-without-as-keyed/_config.js

@@ -0,0 +1,13 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `<button>update</button><p>3</p><p>2</p><p>1</p>`,
+
+	async test({ target, assert }) {
+		const [button] = target.querySelectorAll('button');
+
+		flushSync(() => button.click());
+		assert.htmlEqual(target.innerHTML, `<button>update</button><p>1</p><p>2</p><p>3</p>`);
+	}
+});

packages/svelte/tests/runtime-runes/samples/each-without-as-keyed/main.svelte

@@ -0,0 +1,11 @@
+<script>
+	let items = $state([{ id: 3 }, { id: 2 }, { id: 1 }]);
+</script>
+
+<button onclick={() => items = [{ id: 1 }, { id: 2 }, { id: 3 }]}>
+	update
+</button>
+
+{#each items, i (items[i].id)}
+	<p>{items[i].id}</p>
+{/each}