Autosubscribe to nested stores without intermediate assignment

[johnnysprinkles]

Describe the problem

I sometimes have nested stores, i.e. a store that has properties which are themselves stores. To get at the value, I assign to an intermediate variable like so:

let barStore = $foo.barStore;
if (someExpression > $barStore) {
   ...
}

But it would be pretty natural to allow this inline, as in:

if (someExpression > $($foo.barStore)) {
  ...
}

I imagine this has been proposed but couldn't find the issue number.

Describe the proposed solution

An update to the syntax and compiler to allow the above.

Alternatives considered

The status quo.

Importance

nice to have

[Conduitry]

Duplicate of #4079.

#6373 might be another possible way towards this, but that would probably be a Svelte 4 thing.