From 31472878130a5b508f4875a6423f5e8a0709e3c9 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 25 Oct 2024 00:04:34 +0200
Subject: [PATCH] fix: prevent var name clashing for delegated events without
 params (#13896)

---
 .changeset/smooth-dragons-push.md                  |  5 +++++
 .../compiler/phases/3-transform/client/utils.js    |  2 +-
 .../samples/event-without-params-clash/_config.js  | 14 ++++++++++++++
 .../samples/event-without-params-clash/main.svelte |  6 ++++++
 4 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/smooth-dragons-push.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/event-without-params-clash/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/event-without-params-clash/main.svelte

diff --git a/.changeset/smooth-dragons-push.md b/.changeset/smooth-dragons-push.md
new file mode 100644
index 0000000000..6e02748b47
--- /dev/null
+++ b/.changeset/smooth-dragons-push.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent var name clashing for delegated events without params
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/utils.js
index 9463d909bc..2647f0a3be 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/utils.js
@@ -136,7 +136,7 @@ export function build_hoisted_params(node, context) {
 	if (node.params.length === 0) {
 		if (hoisted_params.length > 0) {
 			// For the event object
-			params.push(b.id('_'));
+			params.push(b.id(context.state.scope.generate('_')));
 		}
 	} else {
 		for (const param of node.params) {
diff --git a/packages/svelte/tests/runtime-runes/samples/event-without-params-clash/_config.js b/packages/svelte/tests/runtime-runes/samples/event-without-params-clash/_config.js
new file mode 100644
index 0000000000..3dc265319d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/event-without-params-clash/_config.js
@@ -0,0 +1,14 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	test({ assert, target, logs }) {
+		const btn = target.querySelector('button');
+
+		flushSync(() => {
+			btn?.click();
+		});
+		assert.deepEqual(logs, ['test']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/event-without-params-clash/main.svelte b/packages/svelte/tests/runtime-runes/samples/event-without-params-clash/main.svelte
new file mode 100644
index 0000000000..eea08b3473
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/event-without-params-clash/main.svelte
@@ -0,0 +1,6 @@
+<svelte:options runes />
+<script>
+	let _ = "test"
+</script>
+
+<button onclick={() => { console.log(_)} }></button>
\ No newline at end of file