Uncaught TypeError when using SubMenu in h function

[Ljzn]

• I have searched the issues of this repository and believe that this is not a duplicate.

Version

undefined

Environment

macOS Big Sur, Chrome 89

Reproduction link

https://github.com/Ljzn/vue3-default-slot-error/blob/main/src/main.js

Steps to reproduce

use default slot in a-menu-item, under a-sub-menu

import { h, createApp, resolveComponent } from 'vue'
import antd from 'ant-design-vue'

const titleSlot = () => h('span', null, 'submenu')

// following causes typeError

const menuItems = () => [
  h(resolveComponent('a-menu-item'), {
    key: 1
  }, { default: () => 'item1' })
]

// following code causes warning, but no error

// const menuItems = () => [
//   h(resolveComponent('a-menu-item'), {
//     key: 1
//   }, 'item1')
// ]

const app = (props, ctx) => h(
  resolveComponent('a-menu'),
  {
    mode: 'inline'
  },
  {
    default: () => [
      h(
        resolveComponent('a-sub-menu'),
        {},
        {
          default: menuItems,
          title: titleSlot
        }
      )
    ]
  }
)

createApp(app)
  .use(antd)
  .mount('#app')

What is expected?

no error

What is actually happening?

Uncaught TypeError: children.forEach is not a function
at loopMenuItemRecursively (util.js:33)
at util.js:48
at Array.forEach (<anonymous>)
at loopMenuItemRecursively (util.js:33)
at Proxy.isChildrenSelected2 (SubMenu.js:200)
at Proxy.render39 (SubMenu.js:494)
at renderComponentRoot (runtime-core.esm-bundler.js:846)
at componentEffect (runtime-core.esm-bundler.js:4280)
at reactiveEffect (reactivity.esm-bundler.js:42)
at effect (reactivity.esm-bundler.js:17)

[Ljzn]

can be temporary fixed by return an array in menu-item

const menuItems = () => [
  h(resolveComponent('a-menu-item'), {
    key: 1
  }, { default: () => ['item1'] })
]