v- without directive name accidentally parsed as v-slot

[HerringtonDarkholme]

Version

3.2.7

Reproduction link

vue-next-template-explorer.netlify.app

Steps to reproduce

Input code like <template v->123</template> in template explorer or sfc playground.

What is expected?

Vue should report missing directive name error and treat v- as a plain attribute.

What is actually happening?

v- is parsed as v-slot.

---

It's probably an implementation specific behavior. When the regex v- matches nothing, vue fallbacks to slot
https://github.com/vuejs/vue-next/blob/master/packages/compiler-core/src/parse.ts#L779-L791

[yyx990803]

closed via #4495