Feature or enhancement

After 6bc65c3 is merged, there's one more case we can handle. See this todo:

What happens? assert does not allow := without () in its body.
We need to improve the error message, because current state is not really clear for the user. Why there's a syntax error? How to fix it?

Refs #136616

Linked PRs

• gh-138716: Fix assert a := b syntax error message #138718