With options API, I used to inject "global" variables into the render context with:

Vue.mixin({
	computed: {
		$store: () => store,
	},
})

declare module 'vue/types/vue' {
	interface Vue {
		$store: Store
	}
}

and then refer to it with:

<template>
  <div>store = {{ $store }}</div>
</template>

How would I do the same with composition API? node_modules/@vue/composition-api/dist/component/component.d.ts seems to be exporting a non-augmentable type ComponentRenderProxy with hardcoded set of properties:

export declare type ComponentRenderProxy<P = {}, S = {}, PublicProps = P> = {
    $data: S;
    $props: PublicProps;
    $attrs: Data;
    $refs: Data;
    $slots: Data;
    $root: ComponentInstance | null;
    $parent: ComponentInstance | null;
    $emit: (event: string, ...args: unknown[]) => void;
} & P & S;

so the template fails to validate:

Any ideas?

Also (I'm sure I'm missing something!) why doesn't ComponentRenderProxy simply extend Vue?