No, that's just because the example I used was Rust. In Ruby it would be `if user = User.find(..)` and the same goes for Go and plenty of other languages.
If the construct is not allowed when user is already in scope, it reflects the designer's view that an assignment in a conditional isn't a good thing.
If the construct is allowed when user exists already, with no diagnostic, then it carries the pitfalls that this thread is about.