From acd9eaf2ec8d964fa5770fdbcd76e41809197848 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 22 Aug 2025 22:37:57 +0200
Subject: [PATCH] fix: ensure correct order of template effect values (#16655)

Compiler does sync then async but `memoizer.apply` did it the other way around
---
 .changeset/healthy-crabs-marry.md               |  5 +++++
 .../3-transform/client/visitors/shared/utils.js |  2 +-
 .../async-template-async-sync-mixed/_config.js  |  9 +++++++++
 .../async-template-async-sync-mixed/main.svelte | 17 +++++++++++++++++
 4 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/healthy-crabs-marry.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/main.svelte

diff --git a/.changeset/healthy-crabs-marry.md b/.changeset/healthy-crabs-marry.md
new file mode 100644
index 0000000000..eab29dae4a
--- /dev/null
+++ b/.changeset/healthy-crabs-marry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ensure correct order of template effect values
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
index 014547cf2d..ba140a153e 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
@@ -34,7 +34,7 @@ export class Memoizer {
 	}
 
 	apply() {
-		return [...this.#async, ...this.#sync].map((memo, i) => {
+		return [...this.#sync, ...this.#async].map((memo, i) => {
 			memo.id.name = `$${i}`;
 			return memo.id;
 		});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/_config.js b/packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/_config.js
new file mode 100644
index 0000000000..709b88578f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/_config.js
@@ -0,0 +1,9 @@
+import { tick } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>foo bar</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/main.svelte
new file mode 100644
index 0000000000..2e0ae46f1f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-template-async-sync-mixed/main.svelte
@@ -0,0 +1,17 @@
+<script>
+	function foo() {
+		return 'foo';
+	}
+
+	async function bar() {
+		return Promise.resolve('bar');
+	}
+</script>
+
+<svelte:boundary>
+	<p>{foo()} {await bar()}</p>
+
+	{#snippet pending()}
+		<p>pending</p>
+	{/snippet}
+</svelte:boundary>