fix: prevent false positive non-state warnings for bind:this (#10674)

`bind:this` doesn't need to be a state reference if it will never change
fixes #10435

Author: dummdidumm

packages/svelte/src/compiler/phases/2-analyze/index.js

@@ -460,6 +460,25 @@ export function analyze_component(root, options) {
 						) {
 							continue inner;
 						}
+						// bind:this doesn't need to be a state reference if it will never change
+						if (
+							type === 'BindDirective' &&
+							/** @type {import('#compiler').BindDirective} */ (path[i]).name === 'this'
+						) {
+							for (let j = i - 1; j >= 0; j -= 1) {
+								const type = path[j].type;
+								if (
+									type === 'IfBlock' ||
+									type === 'EachBlock' ||
+									type === 'AwaitBlock' ||
+									type === 'KeyBlock'
+								) {
+									warn(warnings, binding.node, [], 'non-state-reference', name);
+									continue outer;
+								}
+							}
+							continue inner;
+						}
 					}
 
 					warn(warnings, binding.node, [], 'non-state-reference', name);

packages/svelte/tests/validator/samples/runes-referenced-nonstate-bind-this/_config.js

@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});

packages/svelte/tests/validator/samples/runes-referenced-nonstate-bind-this/input.svelte

@@ -0,0 +1,11 @@
+<script>
+	let no_need;
+	let does_need1;
+	let does_need2 = $state();
+</script>
+
+<div bind:this={no_need}></div>
+{#if true}
+	<div bind:this={does_need1}></div>
+	<div bind:this={does_need2}></div>
+{/if}

packages/svelte/tests/validator/samples/runes-referenced-nonstate-bind-this/warnings.json

@@ -0,0 +1,14 @@
+[
+	{
+		"code": "non-state-reference",
+		"message": "does_need1 is updated, but is not declared with $state(...). Changing its value will not correctly trigger updates.",
+		"start": {
+			"column": 5,
+			"line": 3
+		},
+		"end": {
+			"column": 15,
+			"line": 3
+		}
+	}
+]