fix: Don't skip closure captures after let-else

[jDomantas]

As I understand that return was left there by accident. It caused capture analysis to skip the rest of the block after a let-else, and then missed captures caused incorrect results in borrowck, closure hints, layout calculation, etc.

Fixes #15623

I didn't understand why I using the example from #15623 as-is doesn't work - I don't get the warnings unless I remove the call_me() call, even on the same commit as my own RA version which does show those warnings.

[HKalbasi]

Thanks! Can you also add a test for captures themselves? Something like this:

let a = 2;
let b = 3;
let c = 5;
|| {
  let x = a else { return b; };
  let y = c;
};

The closure should capture all variables. You can (ab)use hover tests as IIRC there is no infrastructure for testing closure captures directly.

I didn't understand why I using the example from #15623 as-is doesn't work - I don't get the warnings unless I remove the call_me() call, even on the same commit as my own RA version which does show those warnings.

You probably need to add minicore flags needed for Fn traits.

[jDomantas]

I added an indirect test for captures via layout test, if that's not ok I can look into redoing it with a hover test a bit later.

[HKalbasi]

That works as well. We probably need dedicated capture tests in future.
@bors r+

[bors]

📌 Commit a961068 has been approved by HKalbasi

It is now in the queue for this repository.

[bors]

⌛ Testing commit a961068 with merge 0566644...

[bors]

☀️ Test successful - checks-actions
Approved by: HKalbasi
Pushing 0566644 to master...