fix: allow to access private fields after this reassignment (#11487)

Fixes #11480
Fixes #11476

Author: paoloricciuti

.changeset/gentle-toys-chew.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: allow to access private fields after `this` reassignment

packages/svelte/src/compiler/phases/3-transform/client/visitors/global.js

@@ -13,15 +13,13 @@ export const global_visitors = {
 		}
 	},
 	MemberExpression(node, { state, next }) {
-		if (node.object.type === 'ThisExpression') {
-			// rewrite `this.#foo` as `this.#foo.v` inside a constructor
-			if (node.property.type === 'PrivateIdentifier') {
-				const field = state.private_state.get(node.property.name);
-				if (field) {
-					return state.in_constructor ? b.member(node, b.id('v')) : b.call('$.get', node);
-				}
+		// rewrite `this.#foo` as `this.#foo.v` inside a constructor
+		if (node.property.type === 'PrivateIdentifier') {
+			const field = state.private_state.get(node.property.name);
+			if (field) {
+				return state.in_constructor ? b.member(node, b.id('v')) : b.call('$.get', node);
 			}
-
+		} else if (node.object.type === 'ThisExpression') {
 			// rewrite `this.foo` as `this.#foo.v` inside a constructor
 			if (node.property.type === 'Identifier' && !node.computed) {
 				const field = state.public_state.get(node.property.name);

packages/svelte/tests/runtime-runes/samples/class-private-fields-reassigned-this/_config.js

@@ -0,0 +1,10 @@
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		dev: true
+	},
+	async test({ assert, logs }) {
+		assert.deepEqual(logs, ['init', 1, 'init', 1]);
+	}
+});

packages/svelte/tests/runtime-runes/samples/class-private-fields-reassigned-this/main.svelte

@@ -0,0 +1,23 @@
+<script>
+	class Counter {
+		#count = $state();
+
+		constructor(){
+			const instance = this;
+			instance.#count = 1;
+		}
+
+		get count(){
+			return this.#count;
+		}
+
+		get count2() {
+			const instance = this;
+			return instance.#count;
+		}
+	}
+	const counter = new Counter();
+
+	$inspect(counter.count)
+	$inspect(counter.count2)
+</script>