From 11a2d8e9371b2a1b456f05af7cd4adc0bf212e62 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Fri, 22 Aug 2025 11:33:48 -0700
Subject: [PATCH] fix: only emit `for_await_track_reactivity_loss` in async
 mode (#16644)

Helps with #16610  (but does not fix it yet)
---
 .changeset/tender-masks-bow.md                             | 5 +++++
 .../phases/3-transform/client/visitors/ForOfStatement.js   | 7 ++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/tender-masks-bow.md

diff --git a/.changeset/tender-masks-bow.md b/.changeset/tender-masks-bow.md
new file mode 100644
index 0000000000..224db5fc37
--- /dev/null
+++ b/.changeset/tender-masks-bow.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: only emit `for_await_track_reactivity_loss` in async mode
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ForOfStatement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ForOfStatement.js
index a5d2751812..8ae67f49d1 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ForOfStatement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ForOfStatement.js
@@ -8,7 +8,12 @@ import { dev, is_ignored } from '../../../../state.js';
  * @param {ComponentContext} context
  */
 export function ForOfStatement(node, context) {
-	if (node.await && dev && !is_ignored(node, 'await_reactivity_loss')) {
+	if (
+		node.await &&
+		dev &&
+		!is_ignored(node, 'await_reactivity_loss') &&
+		context.state.options.experimental.async
+	) {
 		const left = /** @type {VariableDeclaration | Pattern} */ (context.visit(node.left));
 		const argument = /** @type {Expression} */ (context.visit(node.right));
 		const body = /** @type {Statement} */ (context.visit(node.body));