fix: ignore as type expressions on property definitions (#14181)

fixes #14179

Author: dummdidumm

.changeset/dull-laws-end.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ignore `as` type expressions on property definitions

packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js

@@ -56,13 +56,14 @@ const visitors = {
 		if (node.exportKind === 'type') return b.empty;
 		return node;
 	},
-	PropertyDefinition(node) {
+	PropertyDefinition(node, { next }) {
 		if (node.accessor) {
 			e.typescript_invalid_feature(
 				node,
 				'accessor fields (related TSC proposal is not stage 4 yet)'
 			);
 		}
+		return next();
 	},
 	TSAsExpression(node, context) {
 		return context.visit(node.expression);
@@ -97,7 +98,7 @@ const visitors = {
 		if ((node.readonly || node.accessibility) && context.path.at(-2)?.kind === 'constructor') {
 			e.typescript_invalid_feature(node, 'accessibility modifiers on constructor parameters');
 		}
-		return node.parameter;
+		return context.visit(node.parameter);
 	},
 	FunctionExpression: remove_this_param,
 	FunctionDeclaration: remove_this_param,

packages/svelte/tests/runtime-runes/samples/typescript/_config.js

@@ -1,6 +1,7 @@
 import { flushSync } from 'svelte';
 import { test } from '../../test';
 
+// This test mainly checks that all types are properly ignored by the compiler
 export default test({
 	html: '<button>clicks: 0</button>',
 

packages/svelte/tests/runtime-runes/samples/typescript/main.svelte

@@ -10,6 +10,7 @@
 
 	class Foo {
 		public name: string;
+		x = 'x' as const;
 		constructor(name: string) {
 			this.name = name;
 		}