> But type declaration may not be in the view port.

Type declaration doesn't have to be in the view; the very point of type annotations is to support static type systems, which you can query about any type. For example, if you use mypy, you can add `reveal_type( any_kind_of_expr )` anywhere in your code and you'll get the most precise type available, be it inferred or declared manually, for that expression at given point in code.