template src reference not supported

[StarHosea]

Describe the bug

A.vue

<template src="./B.vue">
</template>
<script>
export default {
  
}
</script>

B.vue

<template>
   <div>This is real template </div>
</template>

When Vite build the A.vue in library mod , A Component's render compile result like this

function render(_ctx, _cache, $props, $setup, $data, $options) {
  return openBlock(), createElementBlock("template", null, _hoisted_2);
}

That will create a template tag in html. By the way, vue-cli service build works properly

Reproduction

the repo is
https://github.com/StarHosea/vite-template-build-issue.git

System Info

System:
    OS: Windows 10 10.0.19043
    CPU: (8) x64 Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
    Memory: 4.43 GB / 15.85 GB
  Binaries:
    Node: 12.18.4 - E:\DevEnv\nodejs\node.EXE
    Yarn: 1.17.3 - D:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 6.14.6 - E:\DevEnv\nodejs\npm.CMD
  Browsers:
    Chrome: 93.0.4577.82
    Edge: Spartan (44.19041.1023.0), Chromium (94.0.992.31)
    Internet Explorer: 11.0.19041.1202

Used Package Manager

yarn

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/vue-next instead.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

Closing as this isn't expected to work.
vuejs/core#6929