fix: support es2022 class features (#8355)

Follow up to #8349. We also have to bump the parsing ECMAScript version here. Fixes #6900, fixes #6592.

src/compiler/parse/acorn.ts

@@ -3,12 +3,12 @@ import * as code_red from 'code-red';
 
 export const parse = (source: string): Node => code_red.parse(source, {
 	sourceType: 'module',
-	ecmaVersion: 12,
+	ecmaVersion: 13,
 	locations: true
 });
 
 export const parse_expression_at = (source: string, index: number): Node => code_red.parseExpressionAt(source, index, {
 	sourceType: 'module',
-	ecmaVersion: 12,
+	ecmaVersion: 13,
 	locations: true
 });

test/js/samples/class-field/expected.js

@@ -0,0 +1,25 @@
+/* generated by Svelte vX.Y.Z */
+import { SvelteComponent, init, safe_not_equal } from "svelte/internal";
+
+function instance($$self) {
+	class A {
+		p1;
+		p2 = 1;
+		#p3 = 2;
+
+		#getP3() {
+			return this.#p3;
+		}
+	}
+
+	return [];
+}
+
+class Component extends SvelteComponent {
+	constructor(options) {
+		super();
+		init(this, options, instance, null, safe_not_equal, {});
+	}
+}
+
+export default Component;

test/js/samples/class-field/input.svelte

@@ -0,0 +1,12 @@
+<script>
+	class A {
+		p1;
+		p2 = 1;
+
+		#p3 = 2;
+
+		#getP3() {
+			return this.#p3;
+		}
+	}
+</script>