From 92a4ab25569b52cfc56c9b7be5a6b12556652a09 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Sat, 4 Oct 2025 22:43:36 -0700
Subject: [PATCH] fix: correctly transform `$derived` private fields on server

---
 .changeset/seven-flies-drop.md                              | 5 +++++
 .../phases/3-transform/server/visitors/MemberExpression.js  | 6 +-----
 .../samples/class-state-derived-private/main.svelte         | 3 ++-
 3 files changed, 8 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/seven-flies-drop.md

diff --git a/.changeset/seven-flies-drop.md b/.changeset/seven-flies-drop.md
new file mode 100644
index 0000000000..fed9c7dcac
--- /dev/null
+++ b/.changeset/seven-flies-drop.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly transform `$derived` private fields on server
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/MemberExpression.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/MemberExpression.js
index 50b5ae793f..6326e9efe2 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/MemberExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/MemberExpression.js
@@ -7,11 +7,7 @@ import * as b from '#compiler/builders';
  * @param {Context} context
  */
 export function MemberExpression(node, context) {
-	if (
-		context.state.analysis.runes &&
-		node.object.type === 'ThisExpression' &&
-		node.property.type === 'PrivateIdentifier'
-	) {
+	if (context.state.analysis.runes && node.property.type === 'PrivateIdentifier') {
 		const field = context.state.state_fields?.get(`#${node.property.name}`);
 
 		if (field?.type === '$derived' || field?.type === '$derived.by') {
diff --git a/packages/svelte/tests/runtime-runes/samples/class-state-derived-private/main.svelte b/packages/svelte/tests/runtime-runes/samples/class-state-derived-private/main.svelte
index d971566396..92a1f5ab94 100644
--- a/packages/svelte/tests/runtime-runes/samples/class-state-derived-private/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/class-state-derived-private/main.svelte
@@ -9,7 +9,8 @@
 		}
 
 		get embiggened1() {
-			return this.#doubled;
+			const self = this;
+			return self.#doubled;
 		}
 
 		get embiggened2() {