fix: silence false-positive statel value warning (#14958)

fixes #14687

.changeset/tough-guests-sniff.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: silence false-positive stale value warning

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

@@ -171,6 +171,7 @@ function build_assignment(operator, left, right, context) {
 
 	// special case — ignore `bind:prop={getter, (v) => (...)}` / `bind:value={x.y}`
 	if (
+		path.at(-1) === 'BindDirective' ||
 		path.at(-1) === 'Component' ||
 		path.at(-1) === 'SvelteComponent' ||
 		(path.at(-1) === 'ArrowFunctionExpression' &&

packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/_config.js

@@ -1,21 +1,33 @@
 import { flushSync } from 'svelte';
-import { test } from '../../test';
+import { ok, test } from '../../test';
 
 export default test({
 	compileOptions: {
 		dev: true
 	},
 
-	html: `<button>items: null</button> <div>x</div>`,
+	html: `<button>items: null</button> <div>x</div> <input type="checkbox" value="1"><input type="checkbox" value="2">`,
 
 	test({ assert, target, warnings }) {
 		const btn = target.querySelector('button');
+		ok(btn);
 
-		flushSync(() => btn?.click());
-		assert.htmlEqual(target.innerHTML, `<button>items: []</button> <div>x</div>`);
+		flushSync(() => btn.click());
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>items: []</button> <div>x</div> <input type="checkbox" value="1"><input type="checkbox" value="2">`
+		);
 
-		flushSync(() => btn?.click());
-		assert.htmlEqual(target.innerHTML, `<button>items: [0]</button> <div>x</div>`);
+		flushSync(() => btn.click());
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>items: [0]</button> <div>x</div> <input type="checkbox" value="1"><input type="checkbox" value="2">`
+		);
+
+		const input = target.querySelector('input');
+		ok(input);
+		input.checked = true;
+		flushSync(() => input.dispatchEvent(new Event('change', { bubbles: true })));
 
 		assert.deepEqual(warnings, [
 			'Assignment to `items` property (main.svelte:8:24) will evaluate to the right-hand side, not the value of `items` following the assignment. This may result in unexpected behaviour.'

packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/main.svelte

@@ -2,7 +2,7 @@
 	import Test from './Test.svelte';
 
 	let entries = $state([]);
-	let object = $state({ items: null });
+	let object = $state({ items: null, group: [] });
 </script>
 
 <button onclick={() => (object.items ??= []).push(object.items.length)}>
@@ -11,6 +11,8 @@
 
 <!-- these should not emit warnings -->
 <div bind:this={entries[0]}>x</div>
+<input type="checkbox" value=1 bind:group={object.group}>
+<input type="checkbox" value=2 bind:group={object.group}>
 <Test bind:this={entries[1]}></Test>
 <Test bind:this={() => entries[2], (v) => (entries[2] = v)}></Test>
 <Test bind:x={entries[3]}></Test>