找出这个导入用户类型及构造函数为何无法建立可用的标识符契约。
TypeScript
type StoredUser = { id: string; name: string };
type ImportMetadata = { id: number; source: string };
type ImportedUser = StoredUser & ImportMetadata;
function importedUser(
rawId: string,
name: string,
): ImportedUser {
const value = { id: Number(rawId), name, source: "csv" };
return value as unknown as ImportedUser;
}