@memoize // ❌ The compiler should report an error
export class UserInfo {
	@memoize // ❌ report an error
	firstName?: string;
	lastName?: string;

	saveTo(@memoize /* ❌ report an error */ file: string) {
		// TODO
	}

	@memoize // ✅ support getter
	get name() {
		return `${this.firstName} ${this.lastName}`;
	}

	@memoize // ✅ support method
	toString() {
		return this.name;
	}
}