From a41bdb61847516cf99795e97c6cdb4ef8436662f Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 15 Feb 2024 18:04:39 +0100
Subject: [PATCH] fix: check that component wasn't instantiated (#10466)

fixes #10454
---
 .changeset/gentle-owls-hug.md                     | 5 +++++
 packages/svelte/src/runtime/internal/Component.js | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/gentle-owls-hug.md

diff --git a/.changeset/gentle-owls-hug.md b/.changeset/gentle-owls-hug.md
new file mode 100644
index 0000000000..b6c218afa8
--- /dev/null
+++ b/.changeset/gentle-owls-hug.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: check that component wasn't instantiated in `connectedCallback`
diff --git a/packages/svelte/src/runtime/internal/Component.js b/packages/svelte/src/runtime/internal/Component.js
index 3b9848772f..e417176421 100644
--- a/packages/svelte/src/runtime/internal/Component.js
+++ b/packages/svelte/src/runtime/internal/Component.js
@@ -227,7 +227,7 @@ if (typeof HTMLElement === 'function') {
 			if (!this.$$c) {
 				// We wait one tick to let possible child slot elements be created/mounted
 				await Promise.resolve();
-				if (!this.$$cn) {
+				if (!this.$$cn || this.$$c) {
 					return;
 				}
 				function create_slot(name) {