fix: adjust scope parent for named slots (#10843)

fixes #10802

Author: dummdidumm

.changeset/mighty-cooks-scream.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: adjust scope parent for named slots

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

@@ -400,9 +400,9 @@ export function create_scopes(ast, root, allow_reactive_declarations, parent) {
 						(attribute) => attribute.type === 'Attribute' && attribute.name === 'slot'
 					)
 				) {
-					// <div slot="..."> inherits the scope above the component, because slots are hella weird
-					scopes.set(child, state.scope);
-					visit(child);
+					// <div slot="..."> inherits the scope above the component unless the component is a named slot itself, because slots are hella weird
+					scopes.set(child, is_default_slot ? state.scope : scope);
+					visit(child, { scope: is_default_slot ? state.scope : scope });
 				} else {
 					if (child.type === 'ExpressionTag') {
 						// expression tag is a special case — we don't visit it directly, but via process_children,

packages/svelte/tests/runtime-legacy/samples/component-slot-let-scope-4/Nested.svelte

@@ -0,0 +1 @@
+<slot name="inner" text="hello world" />

packages/svelte/tests/runtime-legacy/samples/component-slot-let-scope-4/Nested2.svelte

@@ -0,0 +1,9 @@
+<script>
+	export let text;
+</script>
+
+<div>
+	{text}
+	<hr />
+	<slot name="footer" />
+</div>

packages/svelte/tests/runtime-legacy/samples/component-slot-let-scope-4/_config.js

@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	html: `
+	<div>hello world <hr> <div slot="footer">hello world</div></div>
+	`
+});

packages/svelte/tests/runtime-legacy/samples/component-slot-let-scope-4/main.svelte

@@ -0,0 +1,12 @@
+<script>
+	import Nested from "./Nested.svelte"
+	import Nested2 from "./Nested2.svelte"
+</script>
+
+<Nested>
+	<Nested2 slot="inner" let:text {text}>
+		<div slot="footer">
+			{text}
+		</div>
+	</Nested2>
+</Nested>