return (`Async component${name ? ` <${name}>` : `s`} should be explicitly created via \`defineAsyncComponent()\` ` +
                            `in Vue 3. Plain functions will be treated as functional components in ` +
                            `non-compat build. If you have already migrated all async component ` +
                            `usage and intend to use plain functions for functional components, ` +
                            `you can disable the compat behavior and suppress this ` +