fix: adjust parse return type

It returns the root which contains the Svelte nodes

.changeset/sour-weeks-fix.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: adjust `parse` return type

packages/svelte/src/compiler/index.js

@@ -91,7 +91,7 @@ function handle_compile_error(error, filename, source) {
  * https://svelte.dev/docs/svelte-compiler#svelte-parse
  * @param {string} source
  * @param {{ filename?: string; modern?: boolean }} [options]
- * @returns {import('#compiler').SvelteNode | import('./types/legacy-nodes.js').LegacySvelteNode}
+ * @returns {import('#compiler').Root | import('./types/legacy-nodes.js').LegacyRoot}
  */
 export function parse(source, options = {}) {
 	/** @type {import('#compiler').Root} */
@@ -108,7 +108,7 @@ export function parse(source, options = {}) {
 
 	if (options.modern) {
 		// remove things that we don't want to treat as public API
-		return walk(/** @type {import('#compiler').SvelteNode} */ (ast), null, {
+		return walk(ast, null, {
 			_(node, { next }) {
 				// @ts-ignore
 				delete node.parent;

packages/svelte/src/compiler/legacy.js

@@ -33,15 +33,15 @@ function remove_surrounding_whitespace_nodes(nodes) {
  * Transform our nice modern AST into the monstrosity emitted by Svelte 4
  * @param {string} source
  * @param {import('#compiler').Root} ast
- * @returns {import('./types/legacy-nodes.js').LegacySvelteNode}
+ * @returns {import('./types/legacy-nodes.js').LegacyRoot}
  */
 export function convert(source, ast) {
 	const root =
 		/** @type {import('./types/template.js').SvelteNode | import('./types/legacy-nodes.js').LegacySvelteNode} */ (
 			ast
 		);
 
-	return /** @type {import('./types/legacy-nodes.js').LegacySvelteNode} */ (
+	return /** @type {import('./types/legacy-nodes.js').LegacyRoot} */ (
 		walk(root, null, {
 			_(node, { next }) {
 				// @ts-ignore

packages/svelte/src/compiler/types/legacy-nodes.d.ts

@@ -21,6 +21,13 @@ interface BaseElement extends BaseNode {
 	children: Array<LegacyElementLike>;
 }
 
+export interface LegacyRoot extends BaseNode {
+	html: LegacySvelteNode;
+	css?: any;
+	instance?: any;
+	module?: any;
+}
+
 export interface LegacyAction extends BaseNode {
 	type: 'Action';
 	/** The 'x' in `use:x` */

packages/svelte/types/index.d.ts

@@ -514,7 +514,7 @@ declare module 'svelte/compiler' {
 	export function parse(source: string, options?: {
 		filename?: string | undefined;
 		modern?: boolean | undefined;
-	} | undefined): SvelteNode | LegacySvelteNode;
+	} | undefined): Root | LegacyRoot;
 	/**
 	 * @deprecated Replace this with `import { walk } from 'estree-walker'`
 	 * */
@@ -779,6 +779,13 @@ declare module 'svelte/compiler' {
 		children: Array<LegacyElementLike>;
 	}
 
+	interface LegacyRoot extends BaseNode_1 {
+		html: LegacySvelteNode;
+		css?: any;
+		instance?: any;
+		module?: any;
+	}
+
 	interface LegacyAction extends BaseNode_1 {
 		type: 'Action';
 		/** The 'x' in `use:x` */