fix: correctly apply scope on component children (#9824)

Co-authored-by: Rich Harris <rich.harris@vercel.com>

.changeset/unlucky-boxes-obey.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly apply scope on component children

packages/svelte/src/compiler/phases/scope.js

@@ -370,7 +370,6 @@ export function create_scopes(ast, root, allow_reactive_declarations, parent) {
 			}
 
 			const scope = analyze_let_directives(node, state.scope);
-			scopes.set(node, scope);
 
 			for (const child of node.fragment.nodes) {
 				if (
@@ -382,9 +381,15 @@ export function create_scopes(ast, root, allow_reactive_declarations, parent) {
 					// <div slot="..."> inherits the scope above the component, because slots are hella weird
 					scopes.set(child, state.scope);
 					visit(child);
-				} else if (child.type === 'SnippetBlock') {
-					visit(child, { scope });
 				} else {
+					if (child.type === 'ExpressionTag') {
+						// expression tag is a special case — we don't visit it directly, but via process_children,
+						// so we need to set the scope on the expression rather than the tag itself
+						scopes.set(child.expression, scope);
+					} else {
+						scopes.set(child, scope);
+					}
+
 					visit(child, { scope });
 				}
 			}

packages/svelte/tests/runtime-runes/samples/slot-static/Child.svelte

@@ -0,0 +1,5 @@
+<script>
+	let { message } = $props();
+</script>
+
+<slot {message} />

packages/svelte/tests/runtime-runes/samples/slot-static/_config.js

@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<p>message: hello</p>`
+});

packages/svelte/tests/runtime-runes/samples/slot-static/main.svelte

@@ -0,0 +1,9 @@
+<script>
+	import Child from './Child.svelte';
+
+	let message = 'hello';
+</script>
+
+<Child message={message} let:message>
+	<p>message: {message}</p>
+</Child>