Suspense incorrectly warns that it supports single root node only #4016
Description
Version
3.1.2
Reproduction link
https://codesandbox.io/s/agitated-saha-hu5uf?file=/src/App.vue
Steps to reproduce
The linked repro is a very basic router suspense component:is setup, like so:
<router-view v-slot="{ Component }">
<suspense>
<component :is="Component" />
</suspense>
</router-view>Look at the CodeSandbox console.
What is expected?
No warning.
What is actually happening?
It warns "<Suspense> slots expect a single root node."
I have debugged into filterSingleRoot(children).
It seems the children array (after slot invocation) contains a single item representing <Component :is> (that's expected).
For a reason unknown to me, at this point this vnode is a comment; and comments other than v-if are ignored by filterSingleRoot.
