Messages won't update if used inside a slot

[hdahlheim]

Messages won't update, if the language changes, as soon as they are rendered inside of a component slot. This happens with both APIs. When using the i18n-t component, a warning will appear in the console, but the behavior is the same as the function call, the message won't update.

Console warning:

 [vue-i18n] Not found parent composer. use the global composer.

vue & vue-i18n version

• vue: 3.0.0-beta.14
• vue-i18n: 9.0.0-alpha.10

Reproduction Link

Legacy global scope example updated with slot
https://gist.github.com/hdahlheim/cc3f74474f8040bbe7d68cd29fb7f639

Steps to reproduce

Place any $t()/t() calls or i18n-t components inside the slot of a custom component and change the language.

What is Expected?

The message inside of the slot updates.

What is actually happening?

The message stays the same as on the first render.